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Find video protocols related to scientific articles indexed in Pubmed.
Outcomes of persistently active neovascular age-related macular degeneration treated with VEGF inhibitors: observational study data.
Br J Ophthalmol
PUBLISHED: 09-25-2014
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To describe outcomes of eyes with wet age-related macular degeneration (AMD) subdivided by lesion activity in a large multicentre cohort study.
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Mixed-Metal MIL-100(Sc,M) (M=Al, Cr, Fe) for Lewis Acid Catalysis and Tandem C?C Bond Formation and Alcohol Oxidation.
Chemistry
PUBLISHED: 07-13-2014
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The trivalent metal cations Al(3+) , Cr(3+) , and Fe(3+) were each introduced, together with Sc(3+) , into MIL-100(Sc,M) solid solutions (M=Al, Cr, Fe) by direct synthesis. The substitution has been confirmed by powder X-ray diffraction (PXRD) and solid-state NMR, UV/Vis, and X-ray absorption (XAS) spectroscopy. Mixed Sc/Fe MIL-100 samples were prepared in which part of the Fe is present as ?-Fe2 O3 nanoparticles within the mesoporous cages of the MOF, as shown by XAS, TGA, and PXRD. The catalytic activity of the mixed-metal catalysts in Lewis acid catalysed Friedel-Crafts additions increases with the amount of Sc present, with the attenuating effect of the second metal decreasing in the order Al>Fe>Cr. Mixed-metal Sc,Fe materials give acceptable activity: 40?% Fe incorporation only results in a 20?% decrease in activity over the same reaction time and pure product can still be obtained and filtered off after extended reaction times. Supported ?-Fe2 O3 nanoparticles were also active Lewis acid species, although less active than Sc(3+) in trimer sites. The incorporation of Fe(3+) into MIL-100(Sc) imparts activity for oxidation catalysis and tandem catalytic processes (Lewis acid+oxidation) that make use of both catalytically active framework Sc(3+) and Fe(3+) . A procedure for using these mixed-metal heterogeneous catalysts has been developed for making ketones from (hetero)aromatics and a hemiacetal.
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Influence of the Purkinje-muscle junction on transmural repolarization heterogeneity.
Cardiovasc. Res.
PUBLISHED: 07-03-2014
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To elucidate the properties of the PMJ and myocardium underlying these effects. Transmural heterogeneity of action potential duration (APD) is known to play an important role in arrhythmogenesis. Regions of non-uniformities of APD gradients often overlap considerably with the location of Purkinje-muscle junctions (PMJs). We therefore hypothesized that such junctions are novel sources of local endocardial and transmural heterogeneity of repolarization, and that remodelling due to heart failure modulates this response.
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Water-splitting electrocatalysis in acid conditions using ruthenate-iridate pyrochlores.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 06-28-2014
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The pyrochlore solid solution (Na(0.33)Ce(0.67))2(Ir(1-x)Ru(x))2O7 (0?x?1), containing B-site Ru(IV) and Ir(IV) is prepared by hydrothermal synthesis and used as a catalyst layer for electrochemical oxygen evolution from water at pH<7. The materials have atomically mixed Ru and Ir and their nanocrystalline form allows effective fabrication of electrode coatings with improved charge densities over a typical (Ru,Ir)O2 catalyst. An in?situ study of the catalyst layers using XANES spectroscopy at the Ir L(III) and Ru K?edges shows that both Ru and Ir participate in redox chemistry at oxygen evolution conditions and that Ru is more active than Ir, being oxidized by almost one oxidation state at maximum applied potential, with no evidence for ruthenate or iridate in +6 or higher oxidation states.
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Synthesis, characterization and properties of a family of lead(II)-organic frameworks based on a multi-functional ligand 2-amino-4-sulfobenzoic acid exhibiting auxiliary ligand-dependent dehydration-rehydration behaviours.
Dalton Trans
PUBLISHED: 06-18-2014
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A systematic investigation is reported of the use of the multi-functional ligand 2-amino-4-sulfobenzoate (asba(2-)) to construct lead(II)-organic frameworks in the presence and absence of N-donor auxiliary ligands phen, bipy and bix [phen = 1,10-phenanthroline, bipy = 2,2'-bipyridine and bix = 1,4-(methylene-benzene)bisimidazole]. Under ambient, aqueous conditions the assembly of asba(2-) with Pb(II) and phen or bipy leads to two iso-structural 2D double-layer frameworks, {[Pb2(asba)2(phen)2(H2O)]·2H2O}n (1) and {[Pb2(asba)2(bipy)2(H2O)]·2H2O}n (2). [Pb2(asba)2(bix)2(H2O)2]n (3) is obtained in the presence of the auxiliary ligand bix and possesses a 3D network built up from 2D Pb(II)-asba(2-)-bridged double-layer pillared by bix. A 2D (4,4) topological network [Pb(asba)(H2O)]n (4) is obtained in the absence of any second ligand or presence of some bistriazole bridging spacers. The coordination modes of the ligand asba(2-) in 1-4 are greatly dependent on the type of auxiliary ligand and the compounds exhibit auxiliary ligand-dependent dehydration-rehydration behaviours; 1 shows in situ rapid and reversible dehydration-rehydration behaviour in air, while the iso-structural compound 2 loses crystallinity in air and transforms into {[Pb2(asba)2(bipy)2(H2O)]·H2O}n (2A) verified by TGA, elemental analysis and powder X-ray diffraction analysis (PXRD). 3 also shows reversible dehydration-rehydration behaviour, but it takes around one week to rehydrate even after exposure to water vapor, while the dehydrated phase of 4 rehydrates to a new crystalline material. 1 and 3 fall within the category of the "recoverable collapsing" and "guest-induced re-formation" frameworks. The water molecules in 1 and 3 have some influence on their solid state fluorescent emission intensity.
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Efficient capture of high-quality data on outcomes of treatment for macular diseases: the fight retinal blindness! Project.
Retina (Philadelphia, Pa.)
PUBLISHED: 04-17-2014
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To describe the development of a web-based high-quality data collection tool to track the outcomes of treatment of macular disease in routine practice.
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Conformation-controlled sorption properties and breathing of the aliphatic Al-MOF [Al(OH)(CDC)].
Inorg Chem
PUBLISHED: 04-10-2014
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The Al-MOF CAU-13 ([Al(OH)(trans-CDC)]; trans-H2CDC = trans-1,4-cyclohexanedicarboxylic acid) is structurally related to the MIL-53 compounds that are well-known for their "breathing" behavior, i.e., the framework flexibility upon external stimuli such as the presence of adsorbate molecules. The adsorption properties of CAU-13 were investigated in detail. The sorption isotherms of N2, H2, CH4, CO, CO2, and water were recorded, and the adsorption enthalpies for the gases were determined by microcalorimetry. The structural changes upon adsorption of CO2 were followed with in situ synchrotron powder X-ray diffraction (PXRD). The patterns were analyzed by parametric unit cell refinement, and the preferential arrangement of the CO2 molecules was modeled by density functional theory calculations. The adsorption and separation of mixtures of o-, m-, and p-xylene from mesitylene showed a preferred adsorption of o-xylene. The structures of o/m/p-xylene-loaded CAU-13 were determined from PXRD data. The adsorption of xylene isomers induces a larger pore opening than that in the thermal activation of CAU-13. In the crystal structure of the activated sample CAU-13(empty pore), half of the linkers adopt the a,a confirmation and the other half the e,e conformation, and the presence of a,a-CDC(2-) ions hampers the structural flexibility of CAU-13. However, after the adsorption of xylene, all linkers are present in the e,e conformation, allowing for a wider pore opening by this new type of "breathing".
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What factors are predictive of surgical resection and survival from localised non-small cell lung cancer?
Med. J. Aust.
PUBLISHED: 03-14-2014
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To investigate opportunities to reduce lung cancer mortality after diagnosis of localised non-small cell lung cancer (NSCLC) in New South Wales through surgical resection.
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Reporting of harms by randomised controlled trials in ophthalmology.
Br J Ophthalmol
PUBLISHED: 02-10-2014
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To evaluate the reporting of harms by randomised controlled trials investigating intravitreal therapies for diabetic macular oedema. A thorough literature search identified eligible reports. Two authors independently extracted data from these articles using a prospectively created checklist. The main outcome measure was compliance with the 10 recommendations of the 2004 Consolidated Standards of Reporting Trials statement extension for better harms reporting. Secondary outcomes were the predictors of the number of recommendations met and the amount of space devoted to harms reporting. Thirty-six reports involving 7246 eyes met the criteria for analysis. The fidelity of the data extraction was excellent, with Cohen's ? coefficient of 0.90 for all items extracted. The median number of recommendations met was six, IQR 5-7. Recommendation 4 (describe how harms-related information was collected) was met by 97% of articles and recommendation 8 (present the absolute risk of each adverse event) by 92%. The least frequently met recommendations were numbers 3 (list addressed adverse events with definitions of each), 31%, and 6 (describe participant withdrawals because of harms), 36%. The mean percentage of the results section devoted to harms-related data was 25.8%, SD 10.8%. Harms reporting in published reports of trials of intravitreal therapies for diabetic macular oedema is still not entirely adequate despite increased attention and efforts to standardise it.
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Ruthenium(V) oxides from low-temperature hydrothermal synthesis.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 01-21-2014
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Low-temperature (200?°C) hydrothermal synthesis of the ruthenium oxides Ca1.5 Ru2 O7 , SrRu2 O6 , and Ba2 Ru3 O9 (OH) is reported. Ca1.5 Ru2 O7 is a defective pyrochlore containing Ru(V/VI) ; SrRu2 O6 is a layered Ru(V) oxide with a PbSb2 O6 structure, whilst Ba2 Ru3 O9 (OH) has a previously unreported structure type with orthorhombic symmetry solved from synchrotron X-ray and neutron powder diffraction. SrRu2 O6 exhibits unusually high-temperature magnetic order, with antiferromagnetism persisting to at least 500?K, and refinement using room temperature neutron powder diffraction data provides the magnetic structure. All three ruthenates are metastable and readily collapse to mixtures of other oxides upon heating in air at temperatures around 300-500?°C, suggesting they would be difficult, if not impossible, to isolate under conventional high-temperature solid-state synthesis conditions.
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Distortions of a flexible metal-organic framework from substituted pendant ligands.
Acta Crystallogr B Struct Sci Cryst Eng Mater
PUBLISHED: 01-21-2014
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Four new variants of the 1,4-benzenedicarboxylate MIL-53 structure have been prepared for Co(II) under solvothermal conditions and their structures solved and refined from single-crystal X-ray data. All materials contain pendant pyridine-N-oxide ligands that bridge pairs of Co(II) atoms in the inorganic backbone of the structure via O. By the use of the ligands 3-bromopyridine-N-oxide, 4-methoxypyridine-N-oxide, isoquinoline-N-oxide and 4-phenylpyridine-N-oxide, materials are prepared with the same topology but distinct structures. These illustrate how the MIL-53 structure is able to distort to accommodate the bulk of the various substituents on the pyridine ring. The bulkiest pendant ligand, 4-phenylpyridine-N-oxide, results in a distortion of the diamond-shaped channels in an opposite sense to that seen previously in expanded forms of the parent MIL-53 structure. By comparison with published crystal structures for MIL-53 with various occluded guests, the structural distortions that take place to accommodate the pendant ligands are quantified and it is shown how a twisting of the 1,4-benzenedicarboxylate ligand, instead of a hinging about the ?(2)-carboxylate-metal connection, allows the new structures that are observed.
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Total neutron scattering investigation of the structure of a cobalt gallium oxide spinel prepared by solvothermal oxidation of gallium metal.
J Phys Condens Matter
PUBLISHED: 10-18-2013
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A new solvothermal synthesis route to mixed-metal gallium oxides with the spinel structure has been developed for ternary oxides of ideal composition Ga(3-x)M(x)O(4-y) (M=Co, Zn, Ni). The structure of the novel cobalt gallate produced in this manner, Ga(1.767(8))Co(0.973(8))O(3.752(8)), has been determined from total neutron scattering to be a partially defective spinel with mixed-valent cobalt (approximately 25% Co(3+) and 75% Co(2+)) and with vacancies on approximately 6% of oxygen sites. Pair distribution function (PDF) analysis reveals significant local deviations from the average cubic structure, which are attributed to the conflicting coordination preferences of the Co(2+) (potential Jahn-Teller distortion) and Ga(3+) (Ga off-centring). Reverse Monte Carlo (RMC) modelling supports this conclusion since different metal-oxygen bond-distance distributions are found for the two cations in the refined configuration. An investigation of magnetic properties shows evidence of short-range magnetic order and spin-glass-like behaviour, consistent with the structural disorder of the material.
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A novel approach for deriving global activation maps from non-averaged cardiac optical signals.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 10-11-2013
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Cardiac arrhythmias are often characterized by non-repetitive complex activation sequences. The properties of electrical activity in cardiac tissue, such as activation time (AT), can be accurately determined using optical imaging of electrical signals using voltage-sensitive dyes. The electrical AT of optical action potentials is known to accurately correlate with the time of the maximal derivative (dF/dtmax) of the upstroke of ensemble averaged optical signals. The sensitivity of dF/dtmax to noise is therefore problematic for mapping AT from non-repetitive activity.
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DT-MRI measurement of myolaminar structure: Accuracy and sensitivity to time post-fixation, b-value and number of directions.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 10-11-2013
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DT-MRI has been widely used to quantify myocardial fiber and laminar orientations. These structural orientations influence both the spread of excitation and the reorganization of the myocardium during contraction and are altered in disease states. Studies have sought to validate DT-MRI but questions remain about the accuracy of the method and its sensitivity to the time post-fixation and imaging parameters, including b-value, number of diffusion directions and image voxel size. The advent of high-spatial resolution ex vivo MRI and structure tensor (ST) analysis provides a means of direct validation of DT-MRI and assessment of sensitivity to the b-value, the number of diffusion directions and the image voxel size. We find that, with the fixation method we used, structure does not change with time (up to 72 hours). We show that DT-MRI and ST/HR-MRI are markedly similar measures of fiber orientation but DT-MRI and ST are much less similar measures of laminar orientation. DT-MRI performance is not sensitive to the number of directions, with similar structural orientations measured with 6 or 12 directions. Likewise, DT-MRI performance is generally insensitive to b-value, but laminar measurement is moderately more accurate at b = 500 than for higher b-values.
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Structures and Magnetism of the Rare-Earth Orthochromite Perovskite Solid Solution LaxSm1-xCrO3.
Inorg Chem
PUBLISHED: 10-08-2013
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A new mixed rare-earth orthochromite series, LaxSm1-xCrO3, prepared through single-step hydrothermal synthesis is reported. Solid solutions (x = 0, 0.25, 0.5, 0.625, 0.75, 0.875, and 1.0) were prepared by the hydrothermal treatment of amorphous mixed-metal hydroxides at 370 °C for 48 h. Transmission electron microscopy (TEM) reveals the formation of highly crystalline particles with dendritic-like morphologies. Rietveld refinements against high-resolution powder X-ray diffraction (PXRD) data show that the distorted perovskite structures are described by the orthorhombic space group Pnma over the full composition range. Unit cell volumes and Cr-O-Cr bond angles decrease monotonically with increasing samarium content, consistent with the presence of the smaller lanthanide in the structure. Raman spectroscopy confirms the formation of solid solutions, the degree of their structural distortion. With the aid of shell-model calculations the complex mixing of Raman modes below 250 cm(-1) is clarified. Magnetometry as a function of temperature reveals the onset of low-temperature antiferromagnetic ordering of Cr(3+) spins with weak ferromagnetic component at Néel temperatures (TN) that scale linearly with unit cell volume and structural distortion. Coupling effects between Cr(3+) and Sm(3+) ions are examined with enhanced susceptibilities below TN due to polarization of Sm(3+) moments. At low temperatures the Cr(3+) sublattice is shown to undergo a second-order spin reorientation observed as a rapid decrease of susceptibility.
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Preparation, structural diversity and characterization of a family of Cd(II)-organic frameworks.
Dalton Trans
PUBLISHED: 07-17-2013
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Two Cd(II)-organic frameworks based on 5-iodoisophthalate (IIP(2-)), {[Cd(IIP)(bte)(H2O)]·H2O}n (1) and [Cd(IIP)(bpp)(H2O)]n (2), were obtained either at an ambient temperature or under solvothermal conditions at 120 °C in the presence of 1,4-bis(1,2,4-triazol-1-yl)ethane (bte) and 1,3-bis(4-pyridyl)propane (bpp) as auxiliary ligands, respectively. 1 is a novel discrete single-walled Cd(II)-organic tube (SWCOT) which further extends into a 3D supramolecular interdigitated microporous columnar architecture supported by C-I···I halogen bonds and hydrogen bonds, while 2 exhibits an interesting two-fold interpenetrated 3D diamond network architecture. When the auxiliary ligands bte or bpp were replaced by a longer spacer ligand with more flexibility, 1,4-bis(triazol-1-ylmethyl)benzene (bbtz), the unique discrete single-walled Cd(II)-organic nanotube (SWCONT), {[Cd(IIP)(bbtz)(H2O)]·H2O}n (3), which further extends into a 3D supramolecular microporous framework supported by face-to-face ?···? stacking interactions and hydrogen bonds, was generated at room temperature. Under solvothermal conditions at 120 °C, an interesting two-fold 2D "embracing" (4,4) topological network, [Cd(IIP)(bbtz)(H2O)] (4), which further extends into a two-fold 3D "embracing" supramolecular framework through O-H···O hydrogen bonds, is obtained. 4 loses crystallinity in air, leading to the formation of [Cd(IIP)(bbtz)]·0.5H2O (4A) evidenced by elemental analysis, thermogravimetric analysis (TGA) and powder X-ray diffraction (PXRD). Remarkably, in situ rapid and reversible dehydration-rehydration in static air occurs in 1-3, indicating their potential applications as water absorbent and sensing materials. Dehydrated 1 and 3 show selective gas adsorption of CO2 over N2 and dehydrated 3 can adsorb methanol and ethanol vapors strongly. These compounds exhibit blue fluorescence in the solid state.
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Comparison of Outcomes from a Phase 3 Study of Age-Related Macular Degeneration with a Matched, Observational Cohort.
Ophthalmology
PUBLISHED: 07-11-2013
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To compare outcomes of intravitreal therapy from an observational study cohort with those of participants receiving treatment in the Minimally Classic/Occult Trial of the Anti-VEGF Antibody Ranibizumab (MARINA) for the treatment of neovascular age-related macular degeneration (wet AMD).
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Prospective audit of exudative age-related macular degeneration: 12-month outcomes in treatment-naive eyes.
Invest. Ophthalmol. Vis. Sci.
PUBLISHED: 07-04-2013
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We report the 12-month outcomes of 1140 treatment-naïve eyes with exudative age-related macular degeneration (wet AMD) who were treated for 12 months with intravitreal anti-VEGF drugs in routine clinical practice.
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Isomorphous substitution in a flexible metal-organic framework: mixed-metal, mixed-valent MIL-53 type materials.
Inorg Chem
PUBLISHED: 07-01-2013
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Mixed-metal iron-vanadium analogues of the 1,4-benzenedicarboxylate (BDC) metal-organic framework MIL-53 have been synthesized solvothermally in N,N-dimethylformamide (DMF) from metal chlorides using initial Fe:V ratios of 2:1 and 1:1. At 200 °C and short reaction time (1 h), materials (Fe,V)(II/III)BDC(DMF(1-x)F(x)) crystallize directly, whereas the use of longer reaction times (3 days) at 170 °C yields phases of composition [(Fe,V)(III)0.5(Fe,V)0.5(II)(BDC)(OH,F)](0.5-)·0.5DMA(+) (DMA = dimethylammonium). The identity of the materials is confirmed using high-resolution powder X-ray diffraction, with refined unit cell parameters compared to known pure iron analogues of the same phases. The oxidation states of iron and vanadium in all samples are verified using X-ray absorption near edge structure (XANES) spectroscopy at the metal K-edges. This shows that in the two sets of materials each of the vanadium and the iron centers are present in both +2 and +3 oxidation states. The local environment and oxidation state of iron is confirmed by (57)Fe Mössbauer spectrometry. Infrared and Raman spectroscopies as a function of temperature allowed the conditions for removal of extra-framework species to be identified, and the evolution of ?2-hydroxyls to be monitored. Thus calcination of the mixed-valent, mixed-metal phases [(Fe,V)(III)0.5(Fe,V)0.5(II)(BDC)(OH,F)](0.5-)·0.5DMA(+) yields single-phase MIL-53-type materials, (Fe,V)(III)(BDC)(OH,F). The iron-rich, mixed-metal MIL-53 shows structural flexibility that is distinct from either the pure Fe material or the pure V material, with a thermally induced pore opening upon heating that is reversible upon cooling. In contrast, the material with a Fe:V content of 1:1 shows an irreversible expansion upon heating, akin to the pure vanadium analogue, suggesting the presence of some domains of vanadium-rich regions that can be permanently oxidized to V(IV).
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Critical evaluation of mixed treatment comparison meta-analyses using examples assessing antidepressants and opioid detoxification treatments.
Int J Methods Psychiatr Res
PUBLISHED: 06-06-2013
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Comparing multiple treatment options using meta-analytical methods requires complex statistical methods called mixed treatment comparisons (MTCs). Such methods offer the possibility to summarize data from many clinical trials comparing the different available options. However, those methods are based on a number of assumptions and inherent difficulties that are discussed and illustrated with examples from the psychiatric literature to help readers to understand the strengths and weaknesses of these methods. This review will help enable readers to critically appraise the methodology and results of publications that use MTCs.
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Outcomes.
Pediatr Dent
PUBLISHED: 05-03-2013
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Outcomes encompass multiple factors, not just success and failure. They include other considerations such as being workable and profitable to the dentist and safe and acceptable to the patient. The more biological outcomes are most frequently measured. These measurements are on a scale from least to most predictable outcomes of treatment by the dentist, as shown on the evidence pyramid. Impact trauma is an example of a general scarcity of high-level evidence with treatment because of the nature and individuality of the injuries and the difficulty (or impossibility) of designing controlled clinical trials in humans. Much of the evidence is cohort (retrospective or observational studies), case reports, animal studies, and "expert" opinion. Thus, guidelines are largely based on lower levels of evidence. Nonetheless, the current guidelines provide the clinician with the best evidence that is available. The best opportunity for randomized controlled trials is in prevention. Specifically, mouthguard design and usage can be subjected to higher levels of controlled research. Revitalization and regeneration are relatively new procedures. To date, there is a lack of high levels of evidence to be able to substantiate whether these are clinically feasible to become a routine in practice.
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Outcomes.
J Endod
PUBLISHED: 02-27-2013
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Outcomes encompass multiple factors, not just success and failure. They include other considerations such as being workable and profitable to the dentist and safe and acceptable to the patient. The more biological outcomes are most frequently measured. These measurements are on a scale from least to most predictable outcomes of treatment by the dentist, as shown on the evidence pyramid. Impact trauma is an example of a general scarcity of high-level evidence with treatment because of the nature and individuality of the injuries and the difficulty (or impossibility) of designing controlled clinical trials in humans. Much of the evidence is cohort (retrospective or observational studies), case reports, animal studies, and "expert" opinion. Thus, guidelines are largely based on lower levels of evidence. Nonetheless, the current guidelines provide the clinician with the best evidence that is available. The best opportunity for randomized controlled trials is in prevention. Specifically, mouthguard design and usage can be subjected to higher levels of controlled research. Revitalization and regeneration are relatively new procedures. To date, there is a lack of high levels of evidence to be able to substantiate whether these are clinically feasible to become a routine in practice.
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Adsorption of N/S heterocycles in the flexible metal-organic framework MIL-53(Fe(III)) studied by in situ energy dispersive X-ray diffraction.
Phys Chem Chem Phys
PUBLISHED: 02-25-2013
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The adsorption of N/S-containing heterocyclic organic molecules in the flexible iron(III) terephthalate MIL-53, Fe(III)(OH)(0.6)F(0.4)(O2C-C6H4-CO2)·(H2O), from the liquid phase was studied with in situ energy dispersive X-ray diffraction (EDXRD), in order to follow the adsorption-induced expansion of the structure. For comparison with the diffraction data, liquid phase adsorption isotherms were recorded for uptake of benzothiophene, benzothiazole and indole in isopropanol and in heptane. The solvent not only influences pore opening but is also a competing guest. The in situ EDXRD experiments allow the kinetics of guest uptake and the competition with solvent to be monitored directly. Indole uptake is limited; this adsorbate is barely capable of opening the closed, either hydrated or dehydrated, MIL-53(Fe) structure, or of penetrating the isopropanol-containing material in the concentration range under study. When isopropanol is used as a solvent, the guest molecules benzothiophene and benzothiazole must be present at a certain threshold concentration before substantial adsorption into the metal-organic framework takes place, eventually resulting in full opening of the structure. The fully expanded structures of benzothiophene or benzothiazole loaded MIL-53(Fe) materials have Imcm symmetry and a unit cell volume of ca. 1600 Å(3), and upon uptake of the guest molecules by the closed form (unit cell volume ~1000 Å(3)) no intermediate crystalline phases are seen. Successful uptake by MIL-53(Fe) requires that the adsorbate is primarily a good hydrogen bond acceptor; additionally, based on UV-visible spectroscopy, a charge-transfer interaction between the S atoms of benzothiophene and the aromatic rings in the MOF pore wall is proposed.
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Histologic examination of condensing osteitis in cadaver specimens.
J Endod
PUBLISHED: 02-12-2013
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Condensing osteitis is a radiographic finding, but with no reported histologic investigations in humans. The objectives of this study were to evaluate and describe histologically condensing osteitis in human cadaver jaws. Patterns of bone formation and presence/absence and nature of inflammation were examined.
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Structures of uncharacterised polymorphs of gallium oxide from total neutron diffraction.
Chemistry
PUBLISHED: 01-10-2013
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A structural investigation is reported of polymorphs of Ga(2)O(3) that, despite much interest in their properties, have hitherto remained uncharacterised due to structural disorder. The most crystalline sample yet reported of ?-Ga(2)O(3) was prepared by solvothermal oxidation of gallium metal in ethanolamine. Structure refinement using the Rietveld method reveals ?-Ga(2)O(3) has a defect Fd3m spinel structure, while pair distribution function analysis shows that the short-range structure is better modelled with local F43m symmetry. In further solvothermal oxidation reactions a novel gallium oxyhydroxide, Ga(5)O(7)(OH), is formed, the thermal decomposition of which reveals a new, transient gallium oxide polymorph, ?-Ga(2)O(3), before transformation into ?-Ga(2)O(3). In contrast, the thermal decomposition of Ga(NO(3))(3)·9H(2)O first forms ?-Ga(2)O(3) and then ?-Ga(2)O(3). Examination of in situ thermodiffraction data shows that ?-Ga(2)O(3) is always contaminated with ?-Ga(2)O(3) and with this knowledge a model for its structure was deduced and refined--space group P6(3)mc with a ratio of tetrahedral/octahedral gallium of 2.2:1 in close-packed oxide layers. Importantly, thermodiffraction provides no evidence for the existence of the speculated bixbyite structured ?-Ga(2)O(3); at the early stages of thermal decomposition of Ga(NO(3))(3)·9H(2)O the first distinct phase formed is merely small particles of ?-Ga(2)O(3).
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Electrophysiological and structural determinants of electrotonic modulation of repolarization by the activation sequence.
Front Physiol
PUBLISHED: 01-01-2013
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Spatial dispersion of repolarization is known to play an important role in arrhythmogenesis. Electrotonic modulation of repolarization by the activation sequence has been observed in some species and tissue preparations, but to varying extents. Our study sought to determine the mechanisms underlying species- and tissue-dependent electrotonic modulation of repolarization in ventricles. Epi-fluorescence optical imaging of whole rat hearts and pig left ventricular wedges were used to assess epicardial spatial activation and repolarization characteristics. Experiments were supported by computer simulations using realistic geometries. Tight coupling between activation times (AT) and action potential duration (APD) were observed in rat experiments but not in pig. Linear correlation analysis found slopes of -1.03 ± 0.59 and -0.26 ± 0.13 for rat and pig, respectively (p < 0.0001). In rat, maximal dispersion of APD was 11.0 ± 3.1 ms but dispersion of repolarization time (RT) was relatively homogeneous (8.2 ± 2.7, p < 0.0001). However, in pig no such difference was observed between the dispersion of APD and RT (17.8 ± 6.1 vs. 17.7 ± 6.5, respectively). Localized elevations of APD (12.9 ± 8.3%) were identified at ventricular insertion sites of rat hearts both in experiments and simulations. Tissue geometry and action potential (AP) morphology contributed significantly to determining influence of electrotonic modulation. Simulations of a rat AP in a pig geometry decreased the slope of AT and APD relationships by 70.6% whereas slopes were increased by 75.0% when implementing a pig AP in a rat geometry. A modified pig AP, shortened to match the rat APD, showed little coupling between AT and APD with greatly reduced slope compared to the rat AP. Electrotonic modulation of repolarization by the activation sequence is especially pronounced in small hearts with murine-like APs. Tissue architecture and AP morphology play an important role in electrotonic modulation of repolarization.
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Dissolution kinetics of polycrystalline calcium sulfate-based materials: influence of chemical modification.
ACS Appl Mater Interfaces
PUBLISHED: 09-07-2011
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Using a channel flow cell (CFC) system, the dissolution kinetics of polycrystalline gypsum-based materials have been examined with the aim of understanding their interaction with water, a property that limits the applications of the material in many situations. ICP (inductively coupled plasma) analysis of elemental concentrations in solution as a function of time yields surface fluxes by using a finite element modeling approach to simulate the hydrodynamic behavior within the CFC. After correction for surface roughness, a value for the intrinsic dissolution flux into water of pure polycrystalline gypsum, CaSO(4).2H(2)O, of 1.1 (±0.4) × 10(-8) mol cm(-2) s(-1) has been obtained. The addition of known humid creep inhibitors to the gypsum samples, including boric acid, tartaric acid and 3,4,5-trihydroxybenzoic acid (gallic acid), was found to have little measurable effect on the dissolution kinetics of gypsum: all yielded dissolution fluxes of 1.4 (±0.6) × 10(-8) mol cm(-2) s(-1). However, trisodium trimetaphosphate (STMP) was found to have a small detectable inhibitory effect relative to pure gypsum yielding a flux of 7.4 (±2.0) × 10(-9) mol cm(-2) s(-1). The data strongly suggest that models for humid creep inhibition that involve dissolution-crystallization of gypsum crystallites are less likely than those that involve a hindered ingress of water into the gypsum matrix. For comparison, composite materials that comprised of calcium sulfate anhydrite (CaSO(4)) crystallites bound by a polyphosphate matrix were also studied. For some of these samples, Ca(2+) surface fluxes were observed to be ?1 order of magnitude lower than values for polycrystalline gypsum control substrates, suggesting a useful way to impart water resistance to gypsum-based materials.
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Slowed propagation across the compacta-trabeculata interface: a consequence of fiber and sheet anisotropy.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 08-29-2011
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Transmural myocardial activation is influenced by myocardial structure, including structural differences between the compacta (Cta) and the trabeculata (Tta), although this has not been fully explained. Hearts from rats were Langendorff perfused, stained with DI-4-ANEPPS, the apex was cut off and fluorescence acquired from the exposed short-axis surface. The hearts were stimulated at 160 ms cycle length at the anterior, lateral, posterior left ventricle (LV) and septal sub-epicardial sites. Conduction velocity perpendicular to the wave front orientation was measured in each pixel using a gradient-based approach. After optical mapping the cut surface was imaged using a light microscope and the extent of the Cta and Tta mapped and validated against 50 u, m isotropic MRI images. We used a 3D rat ventricle computational model, with architecture obtained from 200 u, m isotropic diffusion tensor MRI and kinetics from the modified Pandit model to determine the relative roles of fibers and sheets on propagation. We show in the experimental study that circumferential propagation around the LV cavity is fast in the Cta: 63.2±19.5 and is slower in the Tta: 32.7±11.0(?) (mean ± s.d cms-1, ? p < 0.01 by two sample t test). In the simulation study the pattern and velocity are not replicated in an isotropic model (I), are partially replicated in a simulation study including fiber anisotropy (A) and is more fully replicated in orthotropic (O) ventricles (fiber and sheet anisotropy), where the circumferential propagation velocity is, I: Cta: 54.2±3.9; Tta:54.3±3.9; A: Cta:43.6±3.2; Tta: 40.6±6.6; O: Cta: 63.2±19.5; Tta: 32.7±11.9(?). We show that sheet orientation is important in understanding activation differences between Cta and Tta.
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Experimental validation of alternating transillumination for imaging intramural wave propagation.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 08-29-2011
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Current techniques to map intramural activation patterns in ex vivo cardiac tissue have limited spatial resolution. Here, we report on the experimental validation of a novel optical technique that was recently proposed to resolve the size and depth of intramural wave fronts using alternating transillumination (AT). AT was achieved by simultaneously mapping the epi- and endocardial surfaces with two synchronized CCD cameras and rapidly alternating LED illumination between both surfaces. Optical phantoms were made based on tissue optical properties measured using a hybrid optical spectrometer. Spherical fluorescent sources (Scarlet microspheres, Invitrogen, UK) of varying sizes were embedded at known depths in the phantoms. Coronary-perfused procine left ventricular slab preparations were stained with DI-4-ANBDQBS (n = 3) and paced at known intramural depths. In phantoms we were able to reliably estimate the depth of the center of fluorescent sources (9.6 ± 5.4% error), as well as their transmural extent (15.7 ± 11.5% error). In ventricular slabs we were able to localize the sites of origin of intramural excitation waves with a precision of ± 1.6 mm. Transmural conduction velocities were, for the first time, measured optically from the surfaces and found to be 21.0 ± 12.4 cm/s. In conclusion, alternating transillumination is a promising technique for reliable reconstruction of depth and expansion rate of intramural activation wave fronts in cardiac tissue.
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Clinical and functional outcomes in patients with major depressive disorder and painful physical symptoms switched to treatment with duloxetine.
Hum Psychopharmacol
PUBLISHED: 06-18-2011
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This post hoc analysis of a multicenter, single-arm, open-label trial (the Attributes of Response in Depressed Patients Switched to Treatment with Duloxetine [ARDENT] study) assessed the relationship between functional improvement in the Sheehan Disability Scale (SDS) and clinical outcomes of mood, pain, and anxiety over 8 weeks after switching treatment to duloxetine in patients with major depressive disorder.
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Uptake of liquid alcohols by the flexible Fe(III) metal-organic framework MIL-53 observed by time-resolved in situ X-ray diffraction.
Chemistry
PUBLISHED: 05-09-2011
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A comprehensive, time-resolved, energy-dispersive X-ray diffraction study of the uptake of liquid alcohols (methanol, ethanol, propan-1-ol and propan-2-ol) by the flexible metal-organic framework solid MIL-53(Fe)[H(2)O] is reported. In the case of the primary alcohols, a fluorinated version of the MIL-53(Fe) host (C2/c symmetry V ca. 1000 Å(3)), in which a fraction of framework hydroxides are replaced by fluoride, shows uptake of alcohols to give initially a partially expanded phase (C2/c symmetry, V ca. 1200 Å(3)) followed by an expanded form of the material (either Imcm or Pnam symmetry, V ca. 1600 Å(3)). In the case of methanol-water mixtures, the EDXRD data show that the partially open intermediate phase undergoes volume expansion during its existence, before switching to a fully open structure if concentrated methanol is used; analogous behaviour is seen if the initial guest is propan-2-ol, which then is replaced by pyridine, where a continuous shift of Bragg peaks within C2/c symmetry is observed. In contrast to the partially fluorinated materials, the purely hydroxylated host materials show little tendency to stabilise partially open forms of MIL-53(Fe) with primary alcohols and the kinetics of guest introduction are markedly slower without the framework fluorination: this is exemplified by the exchange of water by propan-2-ol, where a partially open C2/c phase is formed in a step-wise manner. Our study defines the various possible pathways of liquid-phase uptake of molecular guests by flexible solid MIL-53(Fe).
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Apical morphology of the palatal roots of maxillary molars by using micro-computed tomography.
J Endod
PUBLISHED: 05-03-2011
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The apical constriction (AC) has been a traditional landmark as an end point of canal preparation and obturation. However, the morphology and incidence of this structure have not been definitively determined. The purpose of this study was to determine these factors by using a noninvasive technology, micro-computed tomography.
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93Nb NMR and DFT investigation of the polymorphs of NaNbO3.
Phys Chem Chem Phys
PUBLISHED: 03-21-2011
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Sodium niobate (NaNbO(3)) has a particularly complex phase diagram, with a series of phase transitions as a function of temperature and pressure, and even at room temperature a number of different structural variations have been suggested. Recent work has demonstrated that bulk powders of NaNbO(3), prepared using a variety of synthetic approaches, contain a mixture of perovskite phases; the commonly reported Pbcm phase and a second, polar phase tentatively identified as belonging to space group P2(1)ma. The two phases exhibit very similar (23)Na MAS NMR spectra, although high-resolution MQMAS spectra were able to distinguish between them. Here, we investigate whether different perovskite polymorphs can be distinguished and/or identified using a variety of (93)Nb NMR methods, including MAS, MQMAS and wideline experiments. We compare the experimental results obtained for these more common perovskite materials to those for the metastable ilmenite polymorph of NaNbO(3). Our experimental results are supported by first-principles calculations of NMR parameters using a planewave pseudopotential approach. The calculated NMR parameters appear very different for each of the phases investigated, but high forces on the atoms indicate many of the structural models derived from diffraction require optimisation of the atomic coordinates. After geometry optimisation, most of these perovskite phases exhibit very similar NMR parameters, in contrast to recent work where it was suggested that (93)Nb provides a useful tool for distinguishing NaNbO(3) polymorphs. Finally, we consider the origin of the quadrupolar coupling in these materials, and its dependence on the deviation from ideality of the NbO(6) octahedra.
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The integral inventory for depression, a new, self-rated clinimetric instrument for the emotional and painful dimensions in major depressive disorder.
Int J Psychiatry Clin Pract
PUBLISHED: 02-08-2011
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To assess the reliability and validity of the Integral Inventory for Depression (IID) scale using post hoc analyses of data from a multi-country study (ClinicalTrials.gov: NCT00561509) of patients with major depressive disorder (MDD).
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How oppositionality, inattention, and hyperactivity affect response to atomoxetine versus methylphenidate: a pooled meta-analysis.
J Atten Disord
PUBLISHED: 02-02-2011
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To assess how threshold oppositional defiant disorder (ODD), inattention, and hyperactivity-impulsivity affect the response to atomoxetine versus methylphenidate.
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A randomized, open-label assessment of response to various doses of atomoxetine in korean pediatric outpatients with attention-deficit/hyperactivity disorder.
Psychiatry Investig
PUBLISHED: 01-19-2011
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This multicenter, randomized, open-label, parallel trial aimed to provide a detailed dose-response profile for atomoxetine in Korean pediatric outpatients with attention-deficit/hyperactivity disorder (ADHD).
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Rapid and reversible formation of a crystalline hydrate of a metal-organic framework containing a tube of hydrogen-bonded water.
Chem. Commun. (Camb.)
PUBLISHED: 11-11-2010
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The flexible metal-organic framework MIL-53(Cr) undergoes a dramatic volume expansion upon immersion in water at room temperature to form a crystalline hydrate in which water is held as a hydrogen-bonded tube: the hydration is readily reversible under ambient conditions as shown by time-resolved powder X-ray diffraction.
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High conductivity in hydrothermally grown AgCuO(2) single crystals verified using focused-ion-beam-deposited nanocontacts.
Inorg Chem
PUBLISHED: 11-04-2010
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The silver-copper mixed oxide AgCuO(2) (also formulated as Ag(2)Cu(2)O(4)) possesses a peculiar electronic structure in which both Ag and Cu are partially oxidized, with the charge being delocalized among the three elements in the oxide. Accordingly, a quasi-metallic behavior should be expected for this oxide, and indeed bulk transport measurements show conductivity values that are orders of magnitude higher than for other members of this novel oxide family. The presence of silver makes thermal sintering an inadequate method to evaluate true conductivity, and thus such measurements were performed on low density pellets, giving an underestimated value for the conductivity. In the present work we present a new synthetic route for AgCuO(2) based on mild hydrothermal reactions that has yielded unprecedented large AgCuO(2) single-crystals well over 1 ?m in size using temperatures as low as 88 °C. We have used a dual beam instrument to apply nanocontacts to those crystals, allowing the in situ measurement of transport properties of AgCuO(2) single crystals. The results show a linear relationship between applied current and measured voltage. The conductivity values obtained are 50 to 300 times higher than those obtained for bulk low density AgCuO(2) pellets, thus confirming the high conductivity of this oxide and therefore supporting the delocalized charge observed by spectroscopic techniques.
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Core ADHD symptom improvement with atomoxetine versus methylphenidate: a direct comparison meta-analysis.
J Atten Disord
PUBLISHED: 09-13-2010
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Previous studies comparing atomoxetine and methylphenidate to treat ADHD symptoms have been equivocal. This noninferiority meta-analysis compared core ADHD symptom response between atomoxetine and methylphenidate in children and adolescents.
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Construction and validation of anisotropic and orthotropic ventricular geometries for quantitative predictive cardiac electrophysiology.
Interface Focus
PUBLISHED: 09-10-2010
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Reaction-diffusion computational models of cardiac electrophysiology require both dynamic excitation models that reconstruct the action potentials of myocytes as well as datasets of cardiac geometry and architecture that provide the electrical diffusion tensor D, which determines how excitation spreads through the tissue. We illustrate an experimental pipeline we have developed in our laboratories for constructing and validating such datasets. The tensor D changes with location in the myocardium, and is determined by tissue architecture. Diffusion tensor magnetic resonance imaging (DT-MRI) provides three eigenvectors e(i) and eigenvalues ?(i) at each voxel throughout the tissue that can be used to reconstruct this architecture. The primary eigenvector e(1) is a histologically validated measure of myocyte orientation (responsible for anisotropic propagation). The secondary and tertiary eigenvectors (e(2) and e(3)) specify the directions of any orthotropic structure if ?(2) is significantly greater than ?(3)-this orthotropy has been identified with sheets or cleavage planes. For simulations, the components of D are scaled in the fibre and cross-fibre directions for anisotropic simulations (or fibre, sheet and sheet normal directions for orthotropic tissues) so that simulated conduction velocities match values from optical imaging or plunge electrode experiments. The simulated pattern of propagation of action potentials in the models is partially validated by optical recordings of spatio-temporal activity on the surfaces of hearts. We also describe several techniques that enhance components of the pipeline, or that allow the pipeline to be applied to different areas of research: Q ball imaging provides evidence for multi-modal orientation distributions within a fraction of voxels, infarcts can be identified by changes in the anisotropic structure-irregularity in myocyte orientation and a decrease in fractional anisotropy, clinical imaging provides human ventricular geometry and can identify ischaemic and infarcted regions, and simulations in human geometries examine the roles of anisotropic and orthotropic architecture in the initiation of arrhythmias.
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Relative association of treatment-emergent adverse events with quality of life of patients with schizophrenia: post hoc analysis from a 3-year observational study.
Hum Psychopharmacol
PUBLISHED: 08-26-2010
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To explore the relative association of adverse events with health-related quality of life (HRQL) in patients (N = 16 091) with schizophrenia, treated with antipsychotic medication.
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Yb3O(OH)6Cl·2H2O: an anion-exchangeable hydroxide with a cationic inorganic framework structure.
J. Am. Chem. Soc.
PUBLISHED: 07-10-2010
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The first anion-exchangeable framework hydroxide, Yb(3)O(OH)(6)Cl·2H(2)O, has been synthesized hydrothermally. This material has a three-dimensional cationic ytterbium oxyhydroxide framework with one-dimensional channels running through the structure in which the chloride anions and water molecules are located. The framework is thermally stable below 200 °C and can be reversibly dehydrated and rehydrated with no loss of crystallinity. Additionally, it is able to undergo anion-exchange reactions with small ions such as carbonate, oxalate, and succinate with retention of the framework structure.
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Dual excitation wavelength epifluorescence imaging of transmural electrophysiological properties in intact hearts.
Heart Rhythm
PUBLISHED: 06-08-2010
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Epifluorescence imaging using voltage-sensitive dyes has provided unique insights into cardiac electrical activity and arrhythmias. However, conventional dyes use blue-green excitation light, which has limited depth penetration.
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Solvothermal synthesis of perovskites and pyrochlores: crystallisation of functional oxides under mild conditions.
Chem Soc Rev
PUBLISHED: 06-07-2010
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In this critical review we consider the large literature that has accumulated in the past 5-10 years concerning solution-mediated crystallisation of complex oxide materials using hydrothermal, or more generally solvothermal, reaction conditions. The aim is to show how the synthesis of dense, mixed-metal oxide materials, usually prepared using the high temperatures associated with solid-chemistry, is perfectly feasible from solution in one step reactions, typically at temperatures as low as 200 °C, and that important families of oxide materials have now been reported to crystallise using such synthetic approaches. We will focus on two common structures seen in oxide chemistry, ABO(3) perovskites and A(2)B(2)O(6)O pyrochlores, and include a systematic survey of the variety of chemical elements now included in these two prototypical structure types, from transition metals, in families of materials that include titanates, niobates, manganites and ferrites, to main-group elements in stannates, plumbates and bismuthates. The significant advantages of solution-mediated crystallisation are well illustrated by the recent literature: examples are provided of elegant control of crystal form from the nanometre to the micron length scale to give thin films, anisotropic crystal morphologies, or hierarchical structures of materials with properties desirable for many important contemporary applications. In addition, new metastable materials have been reported, not stable once high temperatures and pressures are applied and hence not amenable using conventional synthesis. We critically discuss the possible control offered by solvothermal synthesis from crystal chemistry to crystal form and how the discovery of new materials may be achieved. Computer simulation, combinatorial synthesis approaches and in situ methods to follow crystallisation will be vital in providing the predictability in synthesis that is needed for rational design of new materials (232 references).
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Disordered lithium niobate rock-salt materials prepared by hydrothermal synthesis.
Dalton Trans
PUBLISHED: 05-04-2010
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An investigation of the one-step hydrothermal crystallisation of lithium niobates reveals that reaction between Nb(2)O(5) and aqueous LiOH at 240 degrees C yields materials with a disordered rock-salt structure where the metals are statistically distributed over the cation sites. This contrasts with the well-studied reaction between Nb(2)O(5) and NaOH or KOH that produces ANbO(3) (A = Na, K) perovskites. Powder neutron diffraction shows that materials prepared at short reaction times and lower LiOH concentration (2.5 M) are lithium deficient and have a slight excess of niobium, but that at longer periods of reaction in 5 M LiOH, close to the ideal, stoichiometric Li(0.75)Nb(0.25)O composition is produced. Upon annealing this phase cleanly transforms into the known ordered rock-salt material Li(3)NbO(4), a process we have followed using thermodiffractometry, which indicates that transformation begins at approximately 700 degrees C. Solid-state (93)Nb and (7)Li NMR of the disordered and ordered rock-salt phases shows that both contain single metal sites but there is clear evidence for local disorder in the disordered samples. For the ordered material, NMR parameters derived from experiment are also compared to those calculated using density functional theory and are shown to be in good agreement.
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Chirality and diastereoselection in the mu-oxo diiron complexes L(2)Fe-O-FeL(2) (L = bidentate salicylaldiminato).
Dalton Trans
PUBLISHED: 01-14-2010
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A number of bis(salicylaldiminato) (Schiff base) complexes of Fe(II) i.e. L(2)Fe with a variety of ligand substituents and functionality are synthesised, usually by salt metathesis but on one occasion via the (sal)(2)Fe complex, and characterised by standard methods. Two molecular structure determinations indicate the expected tetrahedral geometry. Treatment with dry oxygen yielded the Fe(III) complexes [(FeL(2))(2)-mu-O], generally in high yield and in the absence of hydroxylated impurities; one bulky complex L(2)Fe gave no oxidation product for steric reasons, and one hydroxyl-substituted compound gave an insoluble product. Five molecular structures of these [(FeL(2))(2)-mu-O] compounds were determined. All were homochiral in the sense that the absolute configuration at Fe was the same for both atoms. Three of the structures - those based on optically pure salicylaldimine ligands - were diastereomeric. For two, the diastereomers observed are those predicted on the basis of steric considerations, while a third highly distorted and congested structure represents the unexpected diastereomer. Powder X-ray diffraction confirms high phase purity of the bulk samples (i.e. they are diastereomerically pure to the level detectable). These investigations, coupled with molecular structure and NMR studies on model gallium complexes, indicate that the diastereoselection arises from cooperative interactions across the oxo bridge.
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A novel near-infrared voltage-sensitive dye reveals the action potential wavefront orientation at increased depths of cardiac tissue.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 12-08-2009
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Recently, novel near-infrared (NIR) voltage-sensitive dyes were developed for imaging electrical activity in blood-perfused hearts and for tomographic applications. However, their usefulness for conventional surface mapping is unclear. The spectral shift to the NIR range significantly increases the penetration depth of light into the tissue, thus increasing the intramural volume contributing to the optical action potential (OAP). Here, we characterize both computationally and experimentally the effect of increased penetration depth on the OAP upstroke, the OAP component most sensitive to optical scattering and absorption, and the activation maps. Optical imaging of cardiac electrical activity was performed in isolated rat hearts (n = 5) paced from the LV mid free wall. We used the NIR dye JPW-6033 (excitation at 660nm, acquisition at >695nm). The conventional dye DI-4-ANEPPS (excitation at 532nm, acquisition at 700 DF50nm) was used for comparison. To simulate OAP we utilized a hybrid model that couples light transport equations with the model of electrical propagation. As expected, the switch from DI-4-ANEPPS to JPW-6033 significantly increased the upstroke duration: from 3.95 + or - 0.69ms to 5.39 + or - 0.82 ms, respectively. However, activation maps were largely unaffected. The correlation between the shape of the optical upstroke, and the averaged subsurface wave front orientation was also preserved. The computer simulations are in excellent agreement with the experimental data. In conclusion, our analysis suggests that despite significant increase in upstroke duration, the novel NIR dyes can be a useful alternative to conventional dyes in surface mapping applications.
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Electrotonic effects on action potential duration in perfused rat hearts.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 12-08-2009
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Electrotonic interactions in cardiac tissue have been shown previously to modulate dynamical properties of the myocardium such as action potential duration (APD) and action potential duration restitution. A recent computational study indicated that these electrotonic effects may be strongest in small murine hearts. In the present study, we investigate experimentally how APD is modulated by activation sequence and pacing rate using optical mapping in Langendorff perfused rat hearts. Our results show that following an epicardial point stimulus, a strong correlation exists between epicardial APD and activation time, with decreasing APD for increasing activation time. This effect is preserved for all pacing frequencies (6-14 Hz) investigated in this study. Our experimental results are validated by detailed three-dimensional computer simulations. These simulations also demonstrate a strong transmural APD dependence on activation sequence, which, near the pacing site, is sufficient to mask the intrinsic transmural gradient.
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Computational modeling of cardiac dual calcium-voltage optical mapping.
Conf Proc IEEE Eng Med Biol Soc
PUBLISHED: 12-08-2009
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Optical imaging allows mapping the complex spatiotemporal dynamics of transmembrane potential and intracellular calcium in cardiac tissue. Several studies have shown that the epi-fluorescent optical action potential contains contributions from the sub-epicardium, owing to scattering of photons in tissue. Hybrid electro-optical models have allowed careful quantification of these scattering effects and have lead to a better interpretation of the optical action potential. However, until now, these effects have not been investigated for optically recorded calcium transients. Here, we develop a hybrid model of cardiac dual calcium-voltage epi-fluorescence mapping. This model allows simulating both optical action potentials and optical calcium transients and investigating the effects of photon scattering on their synthesis. We find that optical calcium transients contain contributions from sub-epicardial layers up to 0.8 mm below the epicardium. These lead to significant differences in rise time and activation times between the optically acquired calcium signal and the epicardial intracellular calcium concentration. As has been the case with optically recording action potentials, these results should be taken into account in the interpretation of experimental optical measurements of intracellular calcium.
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Identify and define all diagnostic terms for periapical/periradicular health and disease states.
J Endod
PUBLISHED: 11-26-2009
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The purpose of this in-depth investigation was to identify, clarify, and substantiate clinical terminology relative to apical/periapical/periradicular diagnostic states, which is used routinely in the provision of endodontic care. Furthermore, the information gleaned from this investigation was used to link diagnostic categories to symptoms, pathogenesis, treatment, and prognosis wherever possible, along with establishing the basis for the metrics used in this diagnostic process.
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Polymorphism and variable structural dimensionality in the iron(III) phosphate oxalate system: a new polymorph of 3D [Fe2(HPO4)2(C2O4)(H2O)2] x 2 H2O and the layered material [Fe2(HPO4)2(C2O4)(H2O)2].
Dalton Trans
PUBLISHED: 09-03-2009
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Two new iron (III) phosphate oxalates have been isolated under hydrothermal conditions as phase-pure samples and their crystal structures determined from single crystal X-ray diffraction. [Fe(2)(HPO(4))(2)(C(2)O(4))(H(2)O)(2)] x 2 H(2)O, I, is a polymorph of a known phase and differs in the local arrangement of hydrophosphate, oxalate and coordinated water about iron, presenting a mer orientation of three coordinated phosphates, rather than fac as previously seen. The structure of I is three-dimensionally connected with similar network connectivity to the known phase but different overall topology. [Fe(2)(HPO(4))(2)(C(2)O(4))(H(2)O)(2)], II, has a layered structure constructed from octahedral Fe(III) centres coordinated by hydrophosphate, oxalate and water in a fac arrangement. The amount of water used in synthesis is one of the key experimental parameters in stabilising one phase over the other. Thermogravimetric analysis shows that both I and II ultimately collapse into dense tridymite type FePO(4) above 600 degrees C and variable temperature powder XRD shows that this occurs via crystalline intermediate phases. Variable temperature magnetisation measurements show that both materials order antiferromagnetically at low temperatures, with similar Néel temperatures (approximately 29 K) despite their long-range structural differences.
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Attention-deficit/hyperactivity disorder diagnosis, co-morbidities, treatment patterns, and quality of life in a pediatric population in central and eastern Europe and Asia.
J Child Adolesc Psychopharmacol
PUBLISHED: 08-26-2009
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Attention deficit/hyperactivity disorder (ADHD) is often poorly understood, and treatment practices are variable. This 12-month, prospective, observational study provides information about the diagnosis, co-morbidities, treatment patterns, and quality of life (QOL) of patients aged 6-17 years with ADHD symptoms from eastern Asia and central and eastern Europe. Here, we present baseline data for the 1068 enrolled and eligible patients in the study (median age 8 years, 82.2% male). Patients were grouped into two cohorts based on whether they were prescribed psycho- and/or pharmacotherapy (n = 794) or not (n = 274) at study entry. On average, patients receiving treatment were significantly older (9.1 vs. 8.4 years, p < 0.001), more severely ill (Clinical Global Impressions [CGI]-ADHD-S, 4.6 vs. 4.2, p < 0.001; Child Symptom Inventory-4 Parent Checklist (CSI-4) ADHD:C, 35.2 vs. 31.9, p < 0.001), and had significantly higher CSI-4 symptom severity scores relating to various co-morbidities than patients not receiving treatment. At study initiation, patients health-related QOL was significantly impaired as measured on the Child Health and Illness Profile-Child Edition (CHIP-CE) rating scale, with significantly more impairment in the treated group of patients for the Comfort, Risks Avoidance, and Achievement domains. These results provide a description of ADHD and treatment practices in these regions and establish a baseline for gauging changes over time in the study sample.
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Time and position resolved in situ X-ray diffraction study of the hydrothermal conversion of gypsum monoliths to hydroxyapatite.
Dalton Trans
PUBLISHED: 08-14-2009
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Time-resolved energy dispersive X-ray diffraction (EDXRD) data have been measured in situ from cast blocks of gypsum, CaSO(4) x 2 H(2)O, in the presence of reactive phosphate solutions under hydrothermal conditions (100 < or = T < or = 180 degrees C) in order to understand the formation of hydroxyapatite monoliths, for applications such as in artificial bone or dental materials. Measurement of data in short (60 s) intervals has thus permitted information about the kinetics and mechanism of transformation of gypsum to hydroxyapatite to be obtained in a non-invasive way, avoiding the irreversible conversion of hydrous intermediate phases that would occur on quenching. At the lower temperatures used gypsum first converts to an amorphous intermediate phase during reaction, but as the temperature is raised to 130 degrees C and above, hydrothermal dehydration to the subhydrate CaSO(4) x 1/2 H(2)O always occurs before hydroxyapatite crystallises. The final crystal size of the hydroxyapatite is estimated from the peak broadening of the EDXRD data and this reveals an increase in crystal dimension with increasing reaction temperature. Comparing measurements from the surface and from the core of the blocks shows that an additional phosphate phase, CaHPO(4), is observed in the core at two temperatures and also that the crystal growth of hydroxyapatite does not penetrate the core of the block on the time scales we have investigated (up to 6 hours). The observations have important implications in the fabrication of hydroxyapatite monoliths from cast gypsum for applications, since the conversion via several intermediate phases may compromise the integrity and mechanical properties of the monoliths.
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Control of polymorphism in NaNbO(3) by hydrothermal synthesis.
Chem. Commun. (Camb.)
PUBLISHED: 03-11-2009
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The metastable ilmenite polymorph of NaNbO(3), instead of the expected perovskite polymorph, may be prepared directly in one step under mild hydrothermal conditions by lowering pH and using close to stoichiometric amounts of metal precursors; in situ energy-dispersive X-ray diffraction shows that crystallisation occurs rapidly via a sequence of intermediate crystalline phases.
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Resin-based versus gutta-percha-based root canal obturation: influence on bacterial leakage in an in vitro model system.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod
PUBLISHED: 01-21-2009
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This study evaluated the ability of a resin-based system (Resilon/Epiphany) and gutta-percha/sealer with warm vertical or cold lateral compaction to prevent coronal leakage.
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The effect of initial duloxetine dosing strategy on nausea in korean patients with major depressive disorder.
Psychiatry Investig
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To assess the relative severity of nausea in patients from Korea with major depressive disorder (MDD) who were treated with duloxetine at low (30 mg) or high (60 mg) doses, with or without food, for the first week of an 8 week treatment.
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Efficacy of organic acids, bacteriocins, and the lactoperoxidase system in inhibiting the growth of Cronobacter spp. in rehydrated infant formula.
J. Food Prot.
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Thirty-three antimicrobial agents, including antimicrobial peptides (nisin, lacticin 3147, isracidin), organic acids, emulsifiers (organic acid esters), glycine, lysozyme, tocopherol, EDTA, milk fat globule membrane, and the lactoperoxidase system (LPOS) were screened for anti-Cronobacter sakazakii activity. The compounds were initially screened individually in parallel in synthetic media. Those showing antimicrobial activity were then tested in reconstituted whole milk and finally in reconstituted powdered infant formula (PIF), using mild temperatures of reconstitution and prolonged storage at room temperature. Propionic acid and monocaprylin (as POEM M-100) in combination showed inhibitory activity at sufficiently low concentrations (0.1 to 0.2%) in milk to be considered as potential antimicrobial additives for the inhibition of C. sakazakii in reconstituted PIF. More interestingly, LPOS, when combined with the broad-spectrum bacteriocins nisin or lacticin 3147, inhibited outgrowth of C. sakazakii at 37°C for 8 h. The combined effects of POEM M-100 and either acetate or propionate and LPOS with lacticin 3147 or nisin were evaluated under the Food and Agriculture Organization of the United Nations-World Health Organization high-risk scenario for PIF, i.e., low temperature of reconstitution and long storage or feeding times at ambient temperature. In the presence of LPOS and lacticin 3147, growth of Cronobacter spp. was inhibited for up to 12 h when the PIF was rehydrated at 40 or 50°C. These results highlight the potential of combinatory approaches to improving the safety of infant milk formula.
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A lithium-organic framework with coordinatively unsaturated metal sites that reversibly binds water.
Chem. Commun. (Camb.)
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The synthesis and characterisation of a three-dimensional lithium-organic framework MIL-145 is described, which upon thermal treatment yields a second open framework, MIL-146, that contains four and three-coordinate lithium centres: the coordinatively unsaturated trigonal planar lithium centres are able to reversibly bind water with crystallinity maintained, while the dehydrated phase shows preferential adsorption of CO(2) over N(2).
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Instant MOFs: continuous synthesis of metal-organic frameworks by rapid solvent mixing.
Chem. Commun. (Camb.)
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A continuous flow reactor allows the preparation of porous metal-organic framework materials with crystallisation induced by rapid mixing of streams of preheated water and solutions of reagents in organic solvent: this gives high volume production (132 g h(-1)) with crystallite size of the products from nanoscale to micron.
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Patient preferences regarding 1-visit versus 2-visit root canal therapy.
J Endod
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Patient preferences should be taken into account by clinicians when treatment planning. The purposes of this study were to describe the number of visits patients preferred when undergoing root canal therapy (RCT) and to assess whether their preferences were related to hypothetical treatment success rates.
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Tuning the breathing behaviour of MIL-53 by cation mixing.
Chem. Commun. (Camb.)
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A mixed cation MIL-53(Cr-Fe) MOF has been obtained by direct synthesis. Multiple experimental techniques have demonstrated the presence of a genuine mixed phase, leading to a breathing behaviour different from either of the single cation analogues.
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Extracting surface activation time from the optically recorded action potential in three-dimensional myocardium.
Biophys. J.
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Optical mapping has become an indispensible tool for studying cardiac electrical activity. However, due to the three-dimensional nature of the optical signal, the optical upstroke is significantly longer than the electrical upstroke. This raises the issue of how to accurately determine the activation time on the epicardial surface. The purpose of this study was to establish a link between the optical upstroke and exact surface activation time using computer simulations, with subsequent validation by a combination of microelectrode recordings and optical mapping experiments. To simulate wave propagation and associated optical signals, we used a hybrid electro-optical model. We found that the time of the surface electrical activation (t(E)) within the accuracy of our simulations coincided with the maximal slope of the optical upstroke (t(F)*) for a broad range of optical attenuation lengths. This was not the case when the activation time was determined at 50% amplitude (t(F50)) of the optical upstroke. The validation experiments were conducted in isolated Langendorff-perfused rat hearts and coronary-perfused pig left ventricles stained with either di-4-ANEPPS or the near-infrared dye di-4-ANBDQBS. We found that t(F)* was a more accurate measure of t(E) than was t(F50) in all experimental settings tested (P = 0.0002). Using t(F)* instead of t(F50) produced the most significant improvement in measurements of the conduction anisotropy and the transmural conduction time in pig ventricles.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.