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Find video protocols related to scientific articles indexed in Pubmed.
Solar cells: understanding the charge-transfer state and singlet exciton emission from solution-processed small-molecule organic solar cells (adv. Mater. 43/2014).
Adv. Mater. Weinheim
PUBLISHED: 11-14-2014
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World-record-performing bulk-heterojunction (BHJ) small molecule solar cells are realized by careful optimization of their solid-state morphology. These BHJ films are transformed from an intimate mixture of the donor and acceptor phases to films with well-defined donor crystallites. In addition to correlating with a high photovoltaic response, the donor crystallites also appear to be linked with the emergence of donor singlet electroluminescence at low applied biases, where only charge-transfer-state emission is expected. On page 7405, T.-Q. Nguyen and co-workers study three blends of high-performing small-molecule solar-cell systems that show the same trend of emerging singlet emission upon an optimized photovoltaic response.
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High open circuit voltage in regioregular narrow band gap polymer solar cells.
J. Am. Chem. Soc.
PUBLISHED: 08-27-2014
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The regioregular narrow band gap (E(g) ~1.5 eV) conjugated polymer PIPCP was designed and synthesized. PIPCP contains a backbone comprised of CPDT-PT-IDT-PT repeat units (CPDT = cyclopentadithiophene, PT = pyridyl[2,1,3]thiadiazole, IDT = indacenodithiophene) and strictly organized PT orientations, such that the pyridyl N-atoms point toward the CPDT fragment. Comparison of PIPCP with the regiorandom counterpart PIPC-RA illustrates that the higher level of molecular order translates to higher power conversion efficiencies (PCEs) when incorporated into bulk heterojunction (BHJ) organic solar cells. Examination of thin films via absorption spectroscopy and grazing incidence wide-angle X-ray diffraction (GIWAXS) experiments provides evidence of higher order within thin films obtained by spin coating. Most significantly, we find that PIPCP:PC61BM blends yield devices with an open circuit voltage (V(oc)) of 0.86 V, while maintaining a PCE of ~6%. Comparison against a wide range of analogous narrow band gap conjugated polymers reveals that this V(oc) value is particularly high for a BHJ system with band gaps in the 1.4-1.5 eV range thereby indicating a very low E(g) - eV(oc) loss.
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Ratiometric Activatable Cell-Penetrating Peptides Label Pancreatic Cancer, Enabling Fluorescence-Guided Surgery, Which Reduces Metastases and Recurrence in Orthotopic Mouse Models.
Ann. Surg. Oncol.
PUBLISHED: 08-11-2014
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The aim of this study was to evaluate the efficacy of using matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9)-cleavable ratiometric activatable cell-penetrating peptides (RACPPs) conjugated to Cy5 and Cy7 fluorophores to accurately label pancreatic cancer for fluorescence-guided surgery (FGS) in an orthotopic mouse model.
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Striking effect of intra- versus intermolecular hydrogen bonding on zwitterions: physical and electronic properties.
J. Am. Chem. Soc.
PUBLISHED: 08-07-2014
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We report the synthesis, characterization, and application of novel zwitterions. The zwitterionic structures consist of a positively charged cyanine and negatively charged dienolate moieties, confirmed by experimental observations and theoretical calculations. Single crystal X-ray studies revealed that BIT-(NPh)2 is a coplanar molecule that forms 1-D chains via ?-? interactions. In contrast, BIT-(NHexyl)2 is a twisted molecule with a dihedral angle of 78° between the charged planes. In charge transport studies, thin films of the flat zwitterion show semiconducting properties, with a hole mobility of 2.1 × 10(-4) cm(2) V(-1) s(-1) while the twisted zwitterion is a high resistivity insulator.
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Matrix-metalloproteinases in head and neck carcinoma-cancer genome atlas analysis and fluorescence imaging in mice.
Otolaryngol Head Neck Surg
PUBLISHED: 08-04-2014
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(1) Obtain matrix-metalloproteinase (MMP) expression profiles for head and neck squamous cell carcinoma (HNSCC) specimens from the Cancer Genomic Atlas (TCGA). (2) Demonstrate HNSCC imaging using MMP-cleavable, fluorescently labeled ratiometric activatable cell-penetrating peptide (RACPP).
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Mapping orientational order in a bulk heterojunction solar cell with polarization-dependent photoconductive atomic force microscopy.
ACS Nano
PUBLISHED: 07-31-2014
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New methods connecting molecular structure, self-organization, and optoelectronic performance are important for understanding the current generation of organic photovoltaic (OPV) materials. In high power conversion efficiency (PCE) OPVs, light-harvesting small-molecules or polymers are typically blended with fullerene derivatives and deposited in thin films, forming a bulk heterojunction (BHJ), a self-assembled three-dimensional nanostructure of electron donors and acceptors that separates and transports charges. Recent data suggest micrometer-scale orientational order of donor domains exists within this complex nanomorphology, but the link to the optoelectronic properties is yet unexplored. Here we introduce polarization-dependent, photoconductive atomic force microscopy (pd-pcAFM) as a combined probe of orientational order and nanoscale optoelectronic properties (?20 nm resolution). Using the donor 7,7'-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl)bis(6-fluoro-4-(5'-hexyl[2,2'-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazole), p-DTS(FBTTh2)2, we show significant spatial dependence of the nanoscale photocurrent with polarized light in both pristine and BHJ blends (up to 7.0% PCE) due to the local alignment of the molecular transition dipoles. By mapping the polarization dependence of the nanoscale photocurrent, we estimate the molecular orientation and orientational order parameter. Liquid crystalline disclinations are observed in all films, in agreement with complementary electron microscopy experiments, and the order parameter exceeds 0.3. The results demonstrate the utility of pd-pcAFM to investigate the optical/structural anisotropy that exists within a well-performing BHJ system and its relationship to optoelectronic properties on both the nanometer and micrometer length scales.
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Operational mechanism of conjugated polyelectrolytes.
J. Am. Chem. Soc.
PUBLISHED: 06-03-2014
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Conjugated polyelectrolytes (CPEs) are versatile materials used in a range of organic optoelectronic applications. Because of their ionic/electronic nature, characterizing these materials is nontrivial, and their operational mechanism is not fully understood. In this work we use a methodology that combines constant-voltage-driven current-density transient measurements with fast current vs voltage scans to allow decoupling of ionic and electronic phenomena. This technique is applied to diodes prepared with cationic CPEs having different charge-compensating anions. Our results indicate that the operational mechanism of these devices is governed by electrochemical doping of the CPE. On the basis of the notion that the saturated depletion layer for the anions consists of the same ?-conjugated backbone material, we discern how the extent and speed of formation of the doped region depend on the anion structure. Apart from addressing fundamental transport questions, this work provides a tool for future characterization of different CPEs and other similar systems.
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Understanding the charge-transfer state and singlet exciton emission from solution-processed small-molecule organic solar cells.
Adv. Mater. Weinheim
PUBLISHED: 05-30-2014
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Electroluminescence (EL) from the charge-transfer state and singlet excitons is observed at low applied voltages from high-performing small-molecule bulk-heterojunction solar cells. Singlet emission from the blends emerges upon altering the processing conditions, such as thermal annealing and processing with a solvent additive, and correlates with improved photovoltaic performance. Low-temperature EL measurements are utilized to access the physics behind the singlet emission.
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Interplay of solvent additive concentration and active layer thickness on the performance of small molecule solar cells.
Adv. Mater. Weinheim
PUBLISHED: 05-29-2014
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A relationship between solvent additive concentration and active layer thickness in small-molecule solar cells is investigated. Specifically, the additive concentration must scale with the amount of semiconductor material and not as absolute concentration in solution. Devices with a wide range of active layers with thickness up to 200 nm can readily achieve efficiencies close to 6% when the right concentration of additive is used.
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Direct observation of doping sites in temperature-controlled, p-doped P3HT thin films by conducting atomic force microscopy.
Adv. Mater. Weinheim
PUBLISHED: 05-05-2014
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The distribution of dopant sites in doped poly(3-hexylthiophene) (P3HT) thin films is characterized using optical absorption, grazing-incidence X-ray diffraction, and conducting atomic force microscopy (c-AFM). It is shown that dopant sites can be directly observed using c-AFM and that the solution temperature dramatically impacts phase separation and conductivity in spin-cast films.
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Mobility guidelines for high fill factor solution-processed small molecule solar cells.
Adv. Mater. Weinheim
PUBLISHED: 04-16-2014
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Analysis of measured charge-carrier mobilities and fill factors in solution-processable small-molecule bulk-heterojunction solar cells reveals that in order to achieve a high FF, the hole and electron mobilities must be >10(-4) cm 2 V(-1) s(-1) . Neat-film mobility measurements are also found to be a useful predictor of the maximum blend film mobility and FF obtained in blend film solar cells.
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Topological considerations for the design of molecular donors with multiple absorbing units.
J. Am. Chem. Soc.
PUBLISHED: 04-02-2014
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The molecule AT1, with two weakly conjugated chromophores, was designed, synthesized, and examined within the context of its film forming tendencies. While the addition of the second chromophore to the central core enables broadening of the absorption spectrum, this change is mostly apparent in films that are grown slowly. Grazing incidence X-ray scattering (GIWAXS) analysis indicates that these spectral characteristics correspond to an increase in solid state ordering. This information, in combination with differential scanning calorimetry, suggests that the overall molecular shape provides a kinetic barrier to crystallization. As a result, one finds the absence of molecular order when AT1 is combined with PC71BM in solution-cast blends. These findings highlight the importance of molecular topology when designing molecular components for solar cell devices.
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Multi-tiered genomic analysis of head and neck cancer ties TP53 mutation to 3p loss.
Nat. Genet.
PUBLISHED: 03-20-2014
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Head and neck squamous cell carcinoma (HNSCC) is characterized by aggressive behavior with a propensity for metastasis and recurrence. Here we report a comprehensive analysis of the molecular and clinical features of HNSCC that govern patient survival. We find that TP53 mutation is frequently accompanied by loss of chromosome 3p and that the combination of these events is associated with a surprising decrease in survival time (1.9 years versus >5 years for TP53 mutation alone). The TP53-3p interaction is specific to chromosome 3p and validates in HNSCC and pan-cancer cohorts. In human papillomavirus (HPV)-positive tumors, in which HPV inactivates TP53, 3p deletion is also common and is associated with poor outcomes. The TP53-3p event is modified by mir-548k expression, which decreases survival further, and is mutually exclusive with mutations affecting RAS signaling. Together, the identified markers underscore the molecular heterogeneity of HNSCC and enable a new multi-tiered classification of this disease.
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Development of a Suzuki cross-coupling reaction between 2-azidoarylboronic pinacolate esters and vinyl triflates to enable the synthesis of [2,3]-fused indole heterocycles.
J. Org. Chem.
PUBLISHED: 03-12-2014
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The scope and limitations of a Suzuki reaction between 2-azidoarylboronic acid pinacolate esters and vinyl triflates are reported. This cross-coupling reaction enables the regioselective synthesis of indoles after a subsequent Rh(II)2-catalyzed sp(2)-C-H bond amination reaction.
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Maintenance of the enteric stem cell niche by bacterial lipopolysaccharides? Evidence and perspectives.
J. Cell. Mol. Med.
PUBLISHED: 02-27-2014
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The enteric nervous system (ENS) has to respond to continuously changing microenvironmental challenges within the gut and is therefore dependent on a neural stem cell niche to keep the ENS functional throughout life. In this study, we hypothesize that this stem cell niche is also affected during inflammation and therefore investigated lipopolysaccharides (LPS) effects on enteric neural stem/progenitor cells (NSPCs). NSPCs were derived from the ENS and cultured under the influence of different LPS concentrations. LPS effects upon proliferation and differentiation of enteric NSPC cultures were assessed using immunochemistry, flow cytometry, western blot, Multiplex ELISA and real-time PCR. LPS enhances the proliferation of enteric NSPCs in a dose-dependent manner. It delays and modifies the differentiation of these cells. The expression of the LPS receptor toll-like receptor 4 on NSPCs could be demonstrated. Moreover, LPS induces the secretion of several cytokines. Flow cytometry data gives evidence for individual subgroups within the NSPC population. ENS-derived NSPCs respond to LPS in maintaining at least partially their stem cell character. In the case of inflammatory disease or trauma where the liberation and exposure to LPS will be increased, the expansion of NSPCs could be a first step towards regeneration of the ENS. The reduced and altered differentiation, as well as the induction of cytokine signalling, demonstrates that the stem cell niche may take part in the LPS-transmitted inflammatory processes in a direct and defined way.
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Silaindacenodithiophene-based molecular donor: morphological features and use in the fabrication of compositionally tolerant, high-efficiency bulk heterojunction solar cells.
J. Am. Chem. Soc.
PUBLISHED: 02-21-2014
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A novel solution-processable small molecule, namely, benzo[1,2-b:4,5-b]bis(4,4'-dihexyl-4H-silolo[3,2-b]thiophene-2,2'-diyl)bis(6-fluoro-4-(5'-hexyl-[2,2'-bithiophene]-5-yl)benzo[c][1,2,5]thiadiazole (p-SIDT(FBTTh2)2), was designed and synthesized by utilizing the silaindacenodithiophene (SIDT) framework as the central D(2) donor unit within the D(1)AD(2)AD(1) chromophore configuration. Relative to the widely studied 7,7'-[4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b']dithiophene-2,6-diyl]bis[6-fluoro-4-(5'-hexyl-[2,2'-bithiophene]-5-yl)benzo[c][1,2,5]thiadiazole] (p-DTS(FBTTh2)2), which contains the stronger donor fragment dithienosilole (DTS) as D(2), one finds that p-SIDT(FBTTh2)2 exhibits a wider band gap and can be used to fabricate bulk heterojunction solar cells with higher open circuit voltage (0.91 V). Most remarkably, thin films comprising p-SIDT(FBTTh2)2 can achieve exceptional levels of self-organization directly via solution deposition. For example, high-resolution transmission electron microscopy analysis shows that p-SIDT(FBTTh2)2 spin-cast from chlorobenzene organizes into crystalline domains with lattice planes that extend over length scales on the order of hundreds of nanometers. Such features suggest liquid crystalline properties during the evolution of the film. Moreover, grazing incidence wide-angle X-ray scattering analysis shows a strong tendency for the molecules to exist with a strong "face-on" orientation relative to the substrate plane. Similar structural features, albeit of more restricted dimensions, can be observed within p-SIDT(FBTTh2)2:PC71BM bulk heterojunction thin films when the films are processed with 0.4% diiodooctane (DIO) solvent additive. DIO use also increases the solar cell power conversion efficiencies (PCEs) from 1.7% to 6.4%. Of significance from a practical device fabrication perspective is that, for p-SIDT(FBTTh2)2:PC71BM blends, there is a wide range of compositions (from 20:80 to 70:30 p-SIDT(FBTTh2)2:PC71BM) that provide good photovoltaic response, i.e., PCE = 4-6%, indicating a robust tendency to form the necessary continuous phases for charge carrier collection. Light intensity photocurrent measurements, charge selective diode fabrication, and internal quantum efficiency determinations were carried out to obtain insight into the mechanism of device operation. Inclusion of DIO in the casting solution results in films that exhibit much lower photocurrent dependence on voltage and a concomitant increase in fill factor. At the optimum blend ratio, devices show high charge carrier mobilities, while mismatched hole and electron mobilities in blends with high or low donor content result in reduced fill factors and device performance.
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Electronic properties of conjugated polyelectrolyte/single-walled carbon nanotube composites.
Adv. Mater. Weinheim
PUBLISHED: 02-07-2014
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Two narrow-bandgap conjugated polyelectrolytes (CPEs) of identical backbone structure but different pendant charges are used to disperse single-walled carbon nanotubes (SWNTs) in MeOH. Films of the resulting CPE:SWNT composites have electrical conductivity dependent on the SWNT loading, which can be increased with acid vapor treatment. The anionic CPE gives higher electrical conductivity for the composite immediately after deposition, whereas a more-significant increase is observed for the cationic counterpart after acid treatment.
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High-mobility field-effect transistors fabricated with macroscopic aligned semiconducting polymers.
Adv. Mater. Weinheim
PUBLISHED: 02-06-2014
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A record high OFET hole mobility, as high as 23.7 cm(2) /Vs, is achieved in macroscopic aligned semiconducting polymers. The high mobility is insensitive to the polymer molecular weight. Polymer chains are aligned along the fiber to facilitate intrachain charge transport.
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Increased mobility induced by addition of a Lewis acid to a Lewis basic conjugated polymer.
Adv. Mater. Weinheim
PUBLISHED: 02-05-2014
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Through simple addition of a Lewis acid to a conjugated polymer bearing a Lewis basic heteroatom, the hole transport of the polymer can be effectively p-doped resulting in a two-orders increase in hole mobility. The temperature dependent hole transport of a variety of Lewis acid concentrations are explored.
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Sumatriptan-associated ischemic colitis: case report and review of the literature and FAERS.
Drug Saf
PUBLISHED: 01-21-2014
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Ischemic colitis (IC) is being increasingly recognized, although specific etiological causes are observed in a minority of patients. While several drugs have been associated with IC, most remain anecdotal reports. We recently treated a patient with IC thought to be related to sumatriptan for migraines, and performed a literature review along with a review of the FDA Adverse Event Reporting System (FAERS) database to identify additional cases.
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Associations between alcohol use disorders and adherence to antiretroviral treatment and quality of life amongst people living with HIV/AIDS.
BMC Public Health
PUBLISHED: 01-05-2014
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We examined the association of alcohol use disorders (AUD) with adherence to and health-related quality of life (HRQOL) outcomes of antiretroviral treatment (ART) for HIV/AIDS patients.
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An optimized triple modality reporter for quantitative in vivo tumor imaging and therapy evaluation.
PLoS ONE
PUBLISHED: 01-01-2014
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We present an optimized triple modality reporter construct combining a far-red fluorescent protein (E2-Crimson), enhanced firefly luciferase enzyme (Luc2), and truncated wild type herpes simplex virus I thymidine kinase (wttk) that allows for sensitive, long-term tracking of tumor growth in vivo by fluorescence, bioluminescence, and positron emission tomography. Two human cancer cell lines (MDA-MB-231 breast cancer and HT-1080 fibrosarcoma cancer) were successfully transduced to express this triple modality reporter. Fluorescence and bioluminescence imaging of the triple modality reporter were used to accurately quantify the therapeutic responses of MDA-MB-231 tumors to the chemotherapeutic agent monomethyl auristatin E in vivo in athymic nude mice. Positive correlation was observed between the fluorescence and bioluminescence signals, and these signals were also positively correlated with the ex vivo tumor weights. This is the first reported use of both fluorescence and bioluminescence signals from a multi-modality reporter construct to measure drug efficacy in vivo.
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Disparities in the severity of influenza illness: a descriptive study of hospitalized and nonhospitalized novel H1N1 influenza-positive patients in New York City: 2009-2010 influenza season.
J Public Health Manag Pract
PUBLISHED: 12-18-2013
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To investigate the association between socioeconomic status (SES) and hospitalization for 2009 H1N1 influenza, independently of access to care and known risk factors for severe influenza illness, among New York City residents during the 2009-2010 influenza season.
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Corticosteroids for dengue - why dont they work?
PLoS Negl Trop Dis
PUBLISHED: 12-01-2013
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Dysregulated immune responses may contribute to the clinical complications that occur in some patients with dengue.
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A structure-property-performance investigation of perylenediimides as electron accepting materials in organic solar cells.
Phys Chem Chem Phys
PUBLISHED: 10-05-2013
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Solution-processed perylenediimides (PDIs) with varying peri and bay substituents are characterized in order to better understand the relationships between molecular structure, solid state order, charge transport, and photovoltaic performance. It was found that bulky bay substituents interfere with molecular packing, leading to low charge transport and photovoltaic efficiencies compared to PDIs with fewer or less disruptive substituents. We assessed the potential of PDIs as acceptors for organic photovoltaics (OPVs) by utilizing a solution-processed bilayer OPV device architecture with the donor benzoporphyrin. At AM1.5G illumination, power conversion efficiencies (PCEs) up to 2.0% are obtained for solution-processed bilayer OPVs employing PDIs as acceptors. These results demonstrate the potential of PDIs as photovoltaic acceptor materials while elucidating the relationships between molecular structure and material properties.
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Dirhodium(II) Carboxylate Catalyzed Formation of 1,2,3-Trisubstituted Indoles from Styryl Azides.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 10-02-2013
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Dirhodium(II)-carboxylate complexes were discovered to promote the selective migration of acyl groups in trisubstituted styryl azides to form 1,2,3-trisubstituted indoles. The styryl azides are readily available in three steps from cyclobutanone and 2-iodoaniline.
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Facile doping of anionic narrow-band-gap conjugated polyelectrolytes during dialysis.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 08-31-2013
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PCPDTBTSO3 K, an anionic, narrow-band-gap conjugated polyelectrolyte, was found to be doped after dialysis. The proposed doping mechanism involves protonation of the polymer backbone, followed by electron transfer from a neutral chain, to generate radical cations, which are stabilized by the pendant sulfonate anions. Formation of polarons is supported by spectroscopy and electrical-conductivity measurements.
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Fluorescence-guided surgery with live molecular navigation--a new cutting edge.
Nat. Rev. Cancer
PUBLISHED: 08-08-2013
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A glowing new era in cancer surgery may be dawning. Using fluorescently labelled markers, surgical molecular navigation means that tumours and nerves can be displayed in real time intra-operatively in contrasting pseudocolours, which allows more complete tumour resection while preserving important structures. These advances can potentially cause a paradigm shift in cancer surgery, improving patient outcome and decreasing overall health-care costs.
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Enhancement of the photoresponse in organic field-effect transistors by incorporating thin DNA layers.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 08-01-2013
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A mechanistic study of the DNA interfacial layer that enhances the photoresponse in n-type field-effect transistors (FET) and lateral photoconductors using a solution-processed fullerene derivative embedded with disperse-red dye, namely PCBDR, is reported. Incorporation of the thin DNA layer simultaneously leads to increasing the electron injection from non-Ohmic contacts into the PCBDR active layer in dark and to increasing the photocurrent under irradiation. Such features lead to the observation of the enhancement of the photoresponsivity in PCBDR FETs up to 10(3) . Kelvin probe microscopy displays that in the presence of the DNA layer, the surface potential of PCBDR has a greater change in response to irradiation, which is rationalized by a larger number of photoinduced surface carriers. Transient absorption spectroscopy confirms that the increase in photoinduced carriers in PCBDR under irradiation is primarily ascribed to the increase in exciton dissociation rates through the PCBDR/DNA interface and this process can be assisted by the interfacial dipole interaction.
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Understanding TiO2 Size-Dependent Electron Transport Properties of a Graphene-TiO2 Photoanode in Dye-Sensitized Solar Cells Using Conducting Atomic Force Microscopy.
Adv. Mater. Weinheim
PUBLISHED: 07-18-2013
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Conducting AFM reveals a continuous conduction network of a TiO2 -graphene composite in DSSC due to a more intimate contact between the smaller sized TiO2 -graphene composite nanosheets,which reduces the internal resistance at TiO2 /TiO2 and TiO2 /FTO interfaces and ultimately leads to a faster and more efficient electron transport in the photoanode.
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Improved light harvesting and improved efficiency by insertion of an optical spacer (ZnO) in solution-processed small-molecule solar cells.
Nano Lett.
PUBLISHED: 07-03-2013
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We demonstrate that the power conversion efficiency can be significantly improved in solution-processed small-molecule solar cells by tuning the thickness of the active layer and inserting an optical spacer (ZnO) between the active layer and the Al electrode. The enhancement in light absorption in the cell was measured with UV-vis absorption spectroscopy and by measurements of the photoinduced carriers generation rate. The ZnO layer used to improve the light-harvesting increases the charge collection efficiency, serves as a blocking layer for holes, and reduces the recombination rate. The combined optical and electrical improvements raise the power conversion efficiency of solution-processed small-molecule solar cells to 8.9%, that is, comparable to that of polymer counterparts.
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Conductive Conjugated Polyelectrolyte as Hole-Transporting Layer for Organic Bulk Heterojunction Solar Cells.
Adv. Mater. Weinheim
PUBLISHED: 06-22-2013
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Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been extensively used as the hole-transporting layer (HTL) in bulk heterojunction (BHJ) solar cells, however, its anisotropic electrical conduction and intrinsic aciditic nature generally limit the device performance. Here we demonstrate the application of a water/alcohol soluble CPE (CPE-K) as HTLs in BHJ solar cells, achieving a PCE up to 8.2%. The more superior and uniform vertical electrical conductivity found in CPE-K reduces the series resistance and provides efficient hole extraction.
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Regioregular pyridyl[2,1,3]thiadiazole-co-indacenodithiophene conjugated polymers.
Chem. Commun. (Camb.)
PUBLISHED: 06-14-2013
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Regioregular conjugated polymers containing alternating pyridyl[2,1,3]thiadiazole (PT) and indacenodithiophene (IDT) structural units were synthesized. In these copolymers, the pyridyl nitrogen atoms on PT are precisely arranged along the backbone so that each one has an adjacent proximal and an adjacent distal counterpart across the two IDT flanking units. We find that despite the absence of obvious differences in orbital energy levels and optical bandgap, the regioregular materials exhibit larger charge carrier mobilities, as determined by using field effect transistor devices, and can yield higher solar cell power conversion efficiencies when mixed with fullerenes in bulk heterojunction active layers.
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Molecular imaging for cancer diagnosis and surgery.
Adv. Drug Deliv. Rev.
PUBLISHED: 06-13-2013
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Novel molecular imaging techniques have the potential to significantly enhance the diagnostic and therapeutic approaches for cancer treatment. For solid tumors in particular, novel molecular enhancers for imaging modalities such as US, CT, MRI and PET may facilitate earlier and more accurate diagnosis and staging which are prerequisites for successful surgical therapy. Enzymatically activatable "smart" molecular MRI probes seem particularly promising because of their potential to image tumors before and after surgical removal without re-administration of the probe to evaluate completeness of surgical resection. Furthermore, the use of "smart" MR probes as part of screening programs may enable detection of small tumors throughout the body in at-risk patient populations. Dual labeling of molecular MR probes with fluorescent dyes can add real time intraoperative guidance facilitating complete tumor resection and preservation of important structures. A truly theranostic approach with the further addition of therapeutic agents to the molecular probe for adjuvant therapy is conceivable for the future.
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Solvent additive effects on small molecule crystallization in bulk heterojunction solar cells probed during spin casting.
Adv. Mater. Weinheim
PUBLISHED: 05-25-2013
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Solvent additive processing can lead to drastic improvements in the power conversion efficiency (PCE) in solution processable small molecule (SPSM) bulk heterojunction solar cells. In situ grazing incidence wide-angle X-ray scattering is used to investigate the kinetics of crystallite formation during and shortly after spin casting. The additive is shown to have a complex effect on structural evolution invoking polymorphism and enhanced crystalline quality of the donor SPSM.
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Host and viral features of human dengue cases shape the population of infected and infectious Aedes aegypti mosquitoes.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 05-14-2013
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Dengue is the most prevalent arboviral disease of humans. The host and virus variables associated with dengue virus (DENV) transmission from symptomatic dengue cases (n = 208) to Aedes aegypti mosquitoes during 407 independent exposure events was defined. The 50% mosquito infectious dose for each of DENV-1-4 ranged from 6.29 to 7.52 log10 RNA copies/mL of plasma. Increasing day of illness, declining viremia, and rising antibody titers were independently associated with reduced risk of DENV transmission. High early DENV plasma viremia levels in patients were a marker of the duration of human infectiousness, and blood meals containing high concentrations of DENV were positively associated with the prevalence of infectious mosquitoes 14 d after blood feeding. Ambulatory dengue cases had lower viremia levels compared with hospitalized dengue cases but nonetheless at levels predicted to be infectious to mosquitoes. These data define serotype-specific viremia levels that vaccines or drugs must inhibit to prevent DENV transmission.
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Molecular doping enhances photoconductivity in polymer bulk heterojunction solar cells.
Adv. Mater. Weinheim
PUBLISHED: 05-12-2013
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Addition of low concentrations (<1:100, dopant:donor) of a fluorinated p-type dopant, F4-TCNQ leads to a considerable enhancement of the photocurrent in PCDTBT:PC70 BM bulk heterojunction solar cells. As a result, the power conversion efficiency increases from 6.41% to 7.94 %.
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[Perivascular epithelioid cell tumours of the uterus].
Ugeskr. Laeg.
PUBLISHED: 05-09-2013
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Perivascular epithelioid cell tumours (PEComas) are rare tumours with unknown malignant potential. We report a case of a 48-year-old woman, who had had many tumours, initially diagnosed as leiomyomas, removed from her uterus and vagina over 16 years. A recurrent tumour and revision of prior specimens revealed PEComa. As free surgical margins could not be obtained, the woman is regularly controlled by magnetic resonance imaging. So far recurrence has not been detected. This case shows that knowledge of PEComas is important to ensure relevant follow-up as these are low malignant tumours that tend to reoccur.
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Tri-Diketopyrrolopyrrole Molecular Donor Materials for High-Performance Solution-Processed Bulk Heterojunction Solar Cells.
Adv. Mater. Weinheim
PUBLISHED: 05-03-2013
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Two new high-performance DPP-containing donor molecules employing a molecular architecture with three DPP chromorphores (tri-DPP) in conjugated backbones are synthesized and characterized. The two tri-DPP molecules with only a structural difference on alkyl substitutions, when blended with PC71 BM, lead to power conversion efficiencies up to 4.8 and 5.5%, respectively.
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Addressing safety liabilities of TfR bispecific antibodies that cross the blood-brain barrier.
Sci Transl Med
PUBLISHED: 05-03-2013
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Bispecific antibodies using the transferrin receptor (TfR) have shown promise for boosting antibody uptake in brain. Nevertheless, there are limited data on the therapeutic properties including safety liabilities that will enable successful development of TfR-based therapeutics. We evaluate TfR/BACE1 bispecific antibody variants in mouse and show that reducing TfR binding affinity improves not only brain uptake but also peripheral exposure and the safety profile of these antibodies. We identify and seek to address liabilities of targeting TfR with antibodies, namely, acute clinical signs and decreased circulating reticulocytes observed after dosing. By eliminating Fc effector function, we ameliorated the acute clinical signs and partially rescued a reduction in reticulocytes. Furthermore, we show that complement mediates a residual decrease in reticulocytes observed after Fc effector function is eliminated. These data raise important safety concerns and potential mitigation strategies for the development of TfR-based therapies that are designed to cross the blood-brain barrier.
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A high-performing solution-processed small molecule:perylene diimide bulk heterojunction solar cell.
Adv. Mater. Weinheim
PUBLISHED: 03-14-2013
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By combining the molecular donor p-DTS(FBTTh2 )2 with a readily produced perylene diimide acceptor we are able to achieve a power conversion efficiency of 3.0%, making this one of the most efficient non-fullerene organic solar cells to date. The reduced power conversion efficiency of the present system compared to the use of phenyl-C71 -butyric acid methyl ester as an electron acceptor is shown to primarily be related to a significant reduction in the internal quantum efficiency. These results indicate the potential of small-molecule:non-fullerene bulk-heterojunction organic photovoltaics.
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Synthesis and properties of two cationic narrow band gap conjugated polyelectrolytes.
J. Am. Chem. Soc.
PUBLISHED: 03-12-2013
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We report the design, synthesis, and optical and electronic properties of two novel narrow band gap conjugated polyelectrolytes (NBGCPEs) based on a poly[2,6-(4,4-bis-alkyl-4H-cyclopenta[2,1-b;3,4-b]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] donor/acceptor backbone. Comparison with the properties of the neutral precursor material shows that the ionic component in these cationic NBGCPEs leads to a red-shift in the absorption spectra and to a modification of the polymer electronic energy levels. Both the HOMO and the LUMO are lowered in energy, with the net effect being dependent on the choice of counterion, i.e. bromide vs tetrakis(1-imidazolyl)borate. Moreover, we unexpectedly find n-type transport in thin-film transistors, as opposed to the widely studied p-type transport in neutral systems with isoelectronic backbones. From these observations we conclude that introduction of ionic functionalities adjacent to semiconducting polymers that exhibit charge-transfer excitations offers unique opportunities for materials design.
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Photoresponse of donor/acceptor blends in organic transistors: a tool for understanding field-assisted charge separation in small molecule bulk heterojunction solar cells.
ACS Appl Mater Interfaces
PUBLISHED: 02-22-2013
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Photoresponse and ambipolar charge transport in organic bulk heterojunctions (BHJ) is investigated using field-effect transistors (FET) based on two donors, poly(3-hexylthiophene) (P3HT) and 3,6-bis(5-(benzofuran-2-yl)thiophen-2-yl)-2,5-bis(2-ethylhexyl)pyrrolo[3,4-c]pyrrole-1,4-dione (DPP(TBFu)2) blends with [6,6]-phenyl-C70-butyric acid methyl ester (PC70BM) acceptor. Upon 100 mW/cm2 AM 1.5 G illumination, P3HT:PC70BM shows an equivalent hole and electron current together with a largely enhanced photoresponse in the FET. The DPP(TBFu)2:PC70BM blends display an electron-dominating transport along with showing a relatively poor photoresponse in FETs upon irradiation. By comparing the two systems, it suggests that DPP(TBFu)2:PC70BM possesses a less-efficient charge separation assisted by electric fields after exciton dissociation. The FET results correlate well to the solar cell device performance and provide further understanding and optimizing of solution-processed DPP small molecule solar cells.
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Genetic variants of MICB and PLCE1 and associations with non-severe dengue.
PLoS ONE
PUBLISHED: 02-11-2013
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A recent genome-wide association study (GWAS) identified susceptibility loci for dengue shock syndrome (DSS) at MICB rs3132468 and PLCE1 rs3740360. The aim of this study was to define the extent to which MICB (rs3132468) and PLCE1 (rs3740360) were associated with less severe clinical phenotypes of pediatric and adult dengue.
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High-efficiency polymer solar cells enhanced by solvent treatment.
Adv. Mater. Weinheim
PUBLISHED: 01-28-2013
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A significant enhancement of efficiency in thieno[3,4-b]-thiophene/benzodithiophene:[6,6]-phenyl C71-butyric acid methyl ester (PTB7:PC70 BM) solar cells can be achieved by methanol treatment. The effects of methanol treatment are shown in an improvement of built-in voltage, a decrease in series resistance, an enhanced charge-transport property, an accelerated and enlarged charge extraction, and a reduced charge recombination, which induce a simultaneous enhancement in open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) in the devices.
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Effects of stereoisomerism on the crystallization behavior and optoelectrical properties of conjugated molecules.
Adv. Mater. Weinheim
PUBLISHED: 01-17-2013
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Three stereoisomers of DPP(TBFu)2 are separated and identified to investigate the effects of stereoisomerism on crystal structures and the optoelectrical properties. The crystal structures and FET mobility are sensitive to stereoisomers, in which the mesomer possesses the highest carrier mobility and the greatest crystallization tendency to dominate the crystallization in spin-cast films of the as-synthesized stereoisomeric mixture.
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Fluorescence imaging in surgery.
IEEE Rev Biomed Eng
PUBLISHED: 01-15-2013
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Although the modern surgical era is highlighted by multiple technological advances and innovations, one area that has remained constant is the dependence of the surgeons vision on white-light reflectance. This renders different body tissues in a limited palette of various shades of pink and red, thereby limiting the visual contrast available to the operating surgeon. Healthy tissue, anatomic variations, and diseased states are seen as slight discolorations relative to each other and differences are inherently limited in dynamic range. In the upcoming years, surgery will undergo a paradigm shift with the use of targeted fluorescence imaging probes aimed at augmenting the surgical armamentarium by expanding the "visible" spectrum available to surgeons. Such fluorescent "smart probes" will provide real-time, intraoperative, pseudo-color, high-contrast delineation of both normal and pathologic tissues. Fluorescent surgical molecular guidance promises another major leap forward to improve patient safety and clinical outcomes, and to reduce overall healthcare costs. This review provides an overview of current and future surgical applications of fluorescence imaging in diseased and nondiseased tissues and focus on the innovative fields of image processing and instrumentation.
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Iron(II) bromide-catalyzed intramolecular C-H bond amination [1,2]-shift tandem reactions of aryl azides.
J. Am. Chem. Soc.
PUBLISHED: 01-03-2013
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Iron(II) bromide catalyzes the transformation of ortho-substituted aryl azides into 2,3-disubstituted indoles through a tandem ethereal C-H bond amination [1,2]-shift reaction. The preference for the 1,2-shift component of the tandem reaction was established to be Me < 1° < 2° < Ph.
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DNA damage accumulation and TRF2 degradation in atypical Werner syndrome fibroblasts with LMNA mutations.
Front Genet
PUBLISHED: 01-01-2013
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Segmental progeroid syndromes are groups of disorders with multiple features suggestive of accelerated aging. One subset of adult-onset progeroid syndromes, referred to as atypical Werner syndrome, is caused by mutations in the LMNA gene, which encodes a class of nuclear intermediate filaments, lamin A/C. We previously described rapid telomere attrition and accelerated replicative senescence in cultured fibroblasts overexpressing mutant lamin A. In this study, we investigated the cellular phenotypes associated with accelerated telomere shortening in LMNA mutant primary fibroblasts. In early passage primary fibroblasts with R133L or L140R LMNA mutations, shelterin protein components were already reduced while cells still retained telomere lengths comparable to those of controls. There was a significant inverse correlation between the degree of abnormal nuclear morphology and the level of TRF2, a shelterin subunit, suggesting a potential causal relationship. Stabilization of the telomeres via the introduction of the catalytic subunit of human telomerase, hTERT (human telomerase reverse transcriptase), did not prevent degradation of shelterin components, indicating that reduced TRF2 in LMNA mutants is not mediated by short telomeres. Interestingly, ?-H2AX foci (reflecting double strand DNA damage) in early passage LMNA mutant primary fibroblasts and LMNA mutant hTERT fibroblasts were markedly increased in non-telomeric regions of DNA. Our results raise the possibility that mutant lamin A/C causes global genomic instability with accumulation of non-telomeric DNA damage as an early event, followed by TRF2 degradation and telomere shortening.
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Regioregular pyridal[2,1,3]thiadiazole ?-conjugated copolymers.
J. Am. Chem. Soc.
PUBLISHED: 09-28-2011
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?-Conjugated, narrow band gap copolymers containing pyridal[2,1,3]thiadiazole (PT) were synthesized via starting materials that prevent random incorporation of the PT heterocycles relative to the backbone vector. Two regioregular structures could be obtained: in one the PTs are oriented in the same direction, and in the other the orientation of the PTs alternates every other repeat unit. Compared to their regiorandom counterparts, the regioregular polymers exhibit a 2 orders of magnitude increase of the hole mobilites, from 0.005 to 0.6 cm(2) V(-1) s(-1), as determined by field-effect transistor measurements.
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The theoretical current-voltage dependence of a non-degenerate disordered organic material obtained with conductive atomic force microscopy.
J Chem Phys
PUBLISHED: 09-08-2011
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We develop a simple continuum model for the current voltage characteristics of a material as measured by the conducting atomic force microscopy, including space charge effects. We address the effect of the point contact on the magnitude of the current and on the transition voltages between the different current regimes by comparing these with the corresponding expressions obtained with planar electrodes.
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Inverting papilloma of the temporal bone: case report and meta-analysis of risk factors.
Otol. Neurotol.
PUBLISHED: 08-06-2011
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To review the literature on inverting papilloma of the middle ear and mastoid with a focus on familiarizing clinicians with its presentation and cause and to discuss its epidemiologic, diagnostic, and therapeutic issues.
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DNA electron injection interlayers for polymer light-emitting diodes.
J. Am. Chem. Soc.
PUBLISHED: 07-06-2011
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Introduction of a DNA interlayer adjacent to an Al cathode in a polymer light-emitting diode leads to lower turn-on voltages, higher luminance efficiencies, and characteristics comparable to those observed using a Ba electrode. The DNA serves to improve electron injection and also functions as a hole-blocking layer. The temporal characteristics of the devices are consistent with an interfacial dipole layer adjacent to the electrode being responsible for the reduction of the electron injection barrier.
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Comparative case series of exostoses and osteomas of the internal auditory canal.
Ann. Otol. Rhinol. Laryngol.
PUBLISHED: 05-19-2011
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Exostoses and osteomas are benign bony lesions of the auditory canal. Although common in the external auditory canal, they are rare and difficult to distinguish in the internal auditory canal (IAC). In this literature review and case presentation, we define radiologic and histologic criteria to differentiate exostoses from osteomas of the IAC. Two patients with exostoses and 1 patient with an osteoma of the IAC are described here. Patient 1 presented with disabling vertigo and was found to have bilateral exostoses with nerve impingement on the right. After removal of the right-sided exostoses via retrosigmoid craniotomy, the patient had complete resolution of her symptoms over 1 year. Patient 2 presented with bilateral pulsatile tinnitus and vertigo and was found to have bilateral IAC exostoses. Patient 3 presented with hearing loss and tinnitus, and a unilateral IAC osteoma was ultimately discovered. Because of the mild nature of their symptoms, patients 2 and 3 were managed without surgery. We show that IAC osteomas can be differentiated from exostoses by radiographic evidence of bone marrow in high-resolution computed tomography scans, or by the presence of fibrovascular channels on histologic analysis. Management of these rare entities is customized on the basis of patient symptoms.
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Metal stress and decreased tree growth in response to biosolids application in greenhouse seedlings and in situ Douglas-fir stands.
Environ. Pollut.
PUBLISHED: 05-12-2011
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To assess physiological impacts of biosolids on trees, metal contaminants and phytochelatins were measured in Douglas-fir stands amended with biosolids in 1982. A subsequent greenhouse study compared these same soils to soils amended with fresh wastewater treatment plant biosolids. Biosolids-amended field soils had significantly higher organic matter, lower pH, and elevated metals even after 25 years. In the field study, no beneficial growth effects were detected in biosolids-amended stands and in the greenhouse study both fresh and historic biosolids amendments resulted in lower seedling growth rates. Phytochelatins - bioindicators of intracellular metal stress - were elevated in foliage of biosolids-amended stands, and significantly higher in roots of seedlings grown with fresh biosolids. These results demonstrate that biosolids amendments have short- and long-term negative effects that may counteract the expected tree growth benefits.
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Improved facial nerve identification with novel fluorescently labeled probe.
Laryngoscope
PUBLISHED: 02-16-2011
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By phage display, we have developed a novel peptide (NP41) that binds selectively to nerves following systemic administration. We evaluated the pattern of facial nerve labeling with fluorescently-labeled NP41 (F-NP41). We also tested whether F-NP41 highlights facial nerves well enough to identify nerve stumps accurately several weeks after nerve transection.
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Effects of mixing techniques on vancomycin-impregnated polymethylmethacrylate.
J Arthroplasty
PUBLISHED: 02-07-2011
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The use of antibiotic-impregnated polymethylmethacrylate in joint arthroplasty is widespread. The Food and Drug Administration has approved commercially prepared antibiotic bone cement, but in a climate of increasingly drug-resistant bacteria, orthopedic surgeons often hand-mix their own. A recent study reported the effects on drug elution of different mixing methods designed to decrease antibiotic particle size and distribute those particles more uniformly. Theoretically, these mixing techniques could also improve antibiotic cement strength; however, the actual effects of these techniques on cement strength are undefined. In the present study, 3 different methods of mixing vancomycin with bone cement were compared. We conclude that the addition of vancomycin to polymethylmethacrylate at commonly accepted concentrations does substantially decrease cement strength and that more complex mixing techniques do not improve cement strength significantly.
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Controlling ion motion in polymer light-emitting diodes containing conjugated polyelectrolyte electron injection layers.
J. Am. Chem. Soc.
PUBLISHED: 02-07-2011
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The properties and function of an anionic conjugated polyelectrolyte (CPE)-containing ion-conducting polyethylene oxide pendant (PF(PEO)CO(2)Na) as electron injection layers (EILs) in polymer light-emitting diodes (PLEDs) are investigated. A primary goal was to design a CPE structure that would enable acceleration of the device temporal response through facilitation of ion motion. Pristine PLEDs containing PF(PEO)CO(2)Na exhibit luminance response times on the order of tenths of seconds. This delay is attributed to the formation of ordered structures within the CPE film, as observed by atomic force microscopy. Complementary evidence is provided by electron transport measurements. The ordered structures are believed to slow ion migration within the CPE EIL and hence result in a longer temporal response time. It is possible to accelerate the response by a combination of thermal and voltage treatments that "lock" ions within the interfaces adjacent to PF(PEO)CO(2)Na. PLED devices with luminance response times of microseconds, a 10(5) fold enhancement, can therefore be achieved. Faster luminance response time opens up the application of PLEDs with CPE layers in display technologies.
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Fluorescent peptides highlight peripheral nerves during surgery in mice.
Nat. Biotechnol.
PUBLISHED: 01-04-2011
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Nerve preservation is an important goal during surgery because accidental transection or injury leads to significant morbidity, including numbness, pain, weakness or paralysis. Nerves are usually identified by their appearance and relationship to nearby structures or detected by local electrical stimulation (electromyography), but thin or buried nerves are sometimes overlooked. Here, we use phage display to select a peptide that binds preferentially to nerves. After systemic injection of a fluorescently labeled version of the peptide in mice, all peripheral nerves are clearly delineated within 2 h. Contrast between nerve and adjacent tissue is up to tenfold, and useful contrast lasts up to 8 h. No changes in behavior or activity are observed after treatment, indicating a lack of obvious toxicity. The fluorescent probe also labels nerves in human tissue samples. Fluorescence highlighting is independent of axonal integrity, suggesting that the probe could facilitate surgical repair of injured nerves and help prevent accidental transection.
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Erosive external otitis: a novel distinct clinical entity of the external auditory canal in nonimmunosuppressed individuals.
Otol. Neurotol.
PUBLISHED: 11-30-2010
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We introduce erosive external otitis (EEO) as a novel erosive process of the external auditory canal in the absence of diabetes or immune suppression.
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Electron injection barrier reduction for organic light-emitting devices by quinacridone derivatives.
Chem. Commun. (Camb.)
PUBLISHED: 09-27-2010
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Water/alcohol-soluble quinacridone derivatives have been synthesized and utilized as an electron injection layer in organic light-emitting diodes. Initial results are very promising, as a device with a layer of Na(+)QHSO(3)(-) adjacent to an Al cathode exhibited a luminance efficiency (1.65 cd A(-1)) that was significantly enhanced relative to the efficiency (0.85 cd A(-1)) of a control device with an unstable, lower work function Ba/Al cathode.
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Reconstruction of conjugated oligoelectrolyte electron injection layers.
J. Am. Chem. Soc.
PUBLISHED: 08-18-2010
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Surface reconstruction of electron injection layers based on conjugated oligoelectrolytes atop an electroluminescent layer occurs in the presence of air. The proposed mechanism involves hydration and concomitant increase of the interfacial energy with the underlying hydrophobic surface followed by dewetting via a nucleation process. No such changes are observed in the case of a conjugated polyelectrolyte, presumably because the lower mobility of the polymer chains leads to a kinetically locked bilayer.
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Large scale screening for haemoglobin disorders in southern Vietnam: implications for avoidance and management.
Br. J. Haematol.
PUBLISHED: 05-20-2010
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In order to obtain an approximate assessment of the public health burden that will be posed by the inherited disorders of haemoglobin in southern Vietnam, several thousand individuals were screened for these conditions. A smaller sample was screened for glucose-6-phosphate dehydrogenase (G6PD) deficiency. The important haemoglobin disorders identified were beta thalassaemia, haemoglobin E and a variety of different forms of alpha thalassaemia. There were sufficient G6PD-deficient individuals to materially affect malaria control programme design. The most remarkable finding was wide variation in the gene frequencies of these conditions among the ethnic groups sampled. The approximate number of babies expected to be born with clinically significant haemoglobin disorders in Vietnam was estimated from the gene-frequency data. This study emphasizes the importance of wide-scale population screening, including ethnic subgroups, to establish the requirements for inherited haemoglobin disorder programmes in resource-limited settings.
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The human immune response to Dengue virus is dominated by highly cross-reactive antibodies endowed with neutralizing and enhancing activity.
Cell Host Microbe
PUBLISHED: 05-19-2010
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Antibodies protect against homologous Dengue virus (DENV) infection but can precipitate severe dengue by promoting heterotypic virus entry via Fc? receptors (Fc?R). We immortalized memory B cells from individuals after primary or secondary infection and analyzed anti-DENV monoclonal antibodies (mAbs) thus generated. MAbs to envelope (E) protein domain III (DIII) were either serotype specific or cross-reactive and potently neutralized DENV infection. DI/DII- or viral membrane protein prM-reactive mAbs neutralized poorly and showed broad cross-reactivity with the four DENV serotypes. All mAbs enhanced infection at subneutralizing concentrations. Three mAbs targeting distinct epitopes on the four DENV serotypes and engineered to prevent Fc?R binding did not enhance infection and neutralized DENV in vitro and in vivo as postexposure therapy in a mouse model of lethal DENV infection. Our findings reveal an unexpected degree of cross-reactivity in human antibodies against DENV and illustrate the potential for an antibody-based therapy to control severe dengue.
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Public health and environmental response to the first case of naturally acquired inhalational anthrax in the United States in 30 years: infection of a new york city resident who worked with dried animal hides.
J Public Health Manag Pract
PUBLISHED: 04-02-2010
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In Pennsylvania on February 16, 2006, a New York City resident collapsed with rigors and was hospitalized. On February 21, the Centers for Disease Control and Prevention and the New York City Department of Health and Mental Hygiene were notified that Bacillus anthracis had been identified in the patients blood. Although the patients history of working with dried animal hides to make African drums indicated the likelihood of a natural exposure to aerosolized anthrax spores, bioterrorism had to be ruled out first. Ultimately, this case proved to be the first case of naturally occurring inhalational anthrax in 30 years. This article describes the epidemiologic and environmental investigation to identify other cases and persons at risk and to determine the source of exposure and scope of contamination. Because stricter regulation of the importation of animal hides from areas where anthrax is enzootic is difficult, public healthcare officials should consider the possibility of future naturally occurring anthrax cases caused by contaminated hides. Federal protocols are needed to assist in the local response, which should be tempered by our growing understanding of the epidemiology of naturally acquired anthrax. These protocols should include recommended methods for reliable and efficient environmental sample collection and laboratory testing, and environmental risk assessments and remediation.
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Directly patternable, highly conducting polymers for broad applications in organic electronics.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 03-08-2010
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Postdeposition solvent annealing of water-dispersible conducting polymers induces dramatic structural rearrangement and improves electrical conductivities by more than two orders of magnitude. We attain electrical conductivities in excess of 50 S/cm when polyaniline films are exposed to dichloroacetic acid. Subjecting commercially available poly(ethylene dioxythiophene) to the same treatment yields a conductivity as high as 250 S/cm. This process has enabled the wide incorporation of conducting polymers in organic electronics; conducting polymers that are not typically processable can now be deposited from solution and their conductivities subsequently enhanced to practical levels via a simple and straightforward solvent annealing process. The treated conducting polymers are thus promising alternatives for metals as source and drain electrodes in organic thin-film transistors as well as for transparent metal oxide conductors as anodes in organic solar cells and light-emitting diodes.
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Are early human chorionic gonadotropin levels after methotrexate therapy a predictor of response in ectopic pregnancy?
Am. J. Obstet. Gynecol.
PUBLISHED: 03-01-2010
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The purpose of this study was to evaluate beta-human chorionic gonadotropin (beta-hCG) levels between days 0 and 4 as a predictor of methotrexate therapy success for ectopic pregnancy.
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Surgery with molecular fluorescence imaging using activatable cell-penetrating peptides decreases residual cancer and improves survival.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 02-16-2010
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The completeness of tumor removal during surgery is dependent on the surgeons ability to differentiate tumor from normal tissue using subjective criteria that are not easily quantifiable. A way to objectively assess tumor margins during surgery in patients would be of great value. We have developed a method to visualize tumors during surgery using activatable cell-penetrating peptides (ACPPs), in which the fluorescently labeled, polycationic cell-penetrating peptide (CPP) is coupled via a cleavable linker to a neutralizing peptide. Upon exposure to proteases characteristic of tumor tissue, the linker is cleaved, dissociating the inhibitory peptide and allowing the CPP to bind to and enter tumor cells. In mice, xenografts stably transfected with green fluorescent protein show colocalization with the Cy5-labeled ACPPs. In the same mouse models, Cy5-labeled free ACPPs and ACPPs conjugated to dendrimers (ACPPDs) delineate the margin between tumor and adjacent tissue, resulting in improved precision of tumor resection. Surgery guided by ACPPD resulted in fewer residual cancer cells left in the animal after surgery as measured by Alu PCR. A single injection of ACPPD dually labeled with Cy5 and gadolinium chelates enabled preoperative whole-body tumor detection by MRI, intraoperative guidance by real-time fluorescence, intraoperative histological analysis of margin status by fluorescence, and postoperative MRI tumor quantification. Animals whose tumors were resected with ACPPD guidance had better long-term tumor-free survival and overall survival than animals whose tumors were resected with traditional bright-field illumination only.
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Activatable cell penetrating peptides linked to nanoparticles as dual probes for in vivo fluorescence and MR imaging of proteases.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 02-16-2010
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High-resolution imaging of molecules intrinsically involved in malignancy and metastasis would be of great value for clinical detection and staging of tumors. We now report in vivo visualization of matrix metalloproteinase activities by MRI and fluorescence of dendrimeric nanoparticles coated with activatable cell penetrating peptides (ACPPs), labeled with Cy5, gadolinium, or both. Uptake of such nanoparticles in tumors is 4- to 15-fold higher than for unconjugated ACPPs. With fluorescent molecules, we are able to detect residual tumor and metastases as small as 200 microm, which can be resected under fluorescence guidance and analyzed histopathologically with fluorescence microscopy. We show that uptake via this mechanism is comparable to that of other near infrared protease sensors, with the added advantage that the approach is translatable to MRI. Once activated, the Gd-labeled nanoparticles deposit high levels (30-50 microM) of Gd in tumor parenchyma with even higher amounts deposited in regions of infiltrative tumor, resulting in useful T(1) contrast lasting several days after injection. These results should improve MRI-guided clinical staging, presurgical planning, and intraoperative fluorescence-guided surgery. The approach may be generalizable to deliver radiation-sensitizing and chemotherapeutic agents.
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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.