bluuebunny/crossref_metadata_2025 huggingface dataset:
Early Screening for Cardiovascular Abnormalities With Preparticipation Echocardiography
Authors: Yim Eugene S. , Basilico Frederick , Corrado Gianmichel
Published: January 2014

Objectives

We have developed the Early Screening for Cardiovascular Abnormalities With Preparticipation Echocardiography protocol to improve false‐positive rates, reduce referrals, and broaden the spectrum of disease that can be captured through preparticipation screening of athletes. This study documents the first application of this protocol and uses case analysis to discuss the potential utility of portable sonography in screening.

Methods

Sixty‐five male collegiate athletes, aged 18 to 25 years, were prospectively enrolled. Each athlete was screened with a history and physical examination, electrocardiography (ECG), and focused echocardiography performed by a noncardiologist sports medicine physician. The history and physical examination were based on the 12‐element American Heart Association recommendations; 2010 European Society of Cardiology criteria were used to screen ECGs. Focused physician‐operated echocardiography was performed to assess for hypertrophic cardiomyopathy and aortic root dilatation. Athletes screening positive were referred to a cardiologist.

Results

Most of the athletes (n = 59) did not screen positive by any screening modality. Three athletes screened positive on ECG but had normal focused echocardiographic findings. Three athletes screened positive by history and physical examination but had normal ECG and focused echocardiographic findings. All athletes screening positive were referred to a cardiologist and eventually cleared for sports participation. No athlete screened positive by focused echocardiography alone. Focused echocardiography was able to reduce the referral rate for hypertrophic cardiomyopathy by 33% and obtained measurements statistically similar to those of formal echocardiography.

Conclusions

This study provides evidence that focused physician‐operated echocardiography can improve false‐positive rates and broaden the spectrum of disease that is detectable through preparticipation screening of athletes.
Extended Transvaginal Sonography in Deep Infiltrating Endometriosis
Authors: León Mauricio , Vaccaro Humberto , Alcázar Juan Luis , Martinez Jaime , Gutierrez Jorge , Amor Fernando , Iturra Alberto , Sovino Hugo
Published: January 2014

Objectives

The purpose of this study was to assess the diagnostic performance of extended transvaginal sonography for diagnosing deep infiltrating endometriosis.

Methods

A prospective study was conducted comprising 51 women (mean age, 32.9 years; range, 23–43 years) with suspected deep infiltrating endometriosis based on clinical symptoms. All women underwent extended transvaginal sonography, which included assessment of 2 pelvic compartments (anterior compartment: bladder and distal ureters; and posterior compartment: posterior vaginal fornix, retrocervical area, pouch of Douglas, and rectosigmoid). The sliding sign for detecting pouch of Douglas obliteration was also assessed. All patients received bowel preparation before sonographic examinations. A single examiner performed all examinations. All women underwent laparoscopic surgery, and histologic confirmation of endometriosis was done. The sensitivity, specificity, positive likelihood ratio (LR+) and negative likelihood ratio (LR−) were calculated.

Results

Some women had more than 1 lesion, giving a total of 55 histologically confirmed lesions (rectosigmoid, n = 13; vagina, n = 5; retrocervical, n = 32; bladder, n = 5). The sensitivity, specificity, and LR+ for rectosigmoid involvement were 100%, 93%, and 14.0, respectively. The sensitivity, specificity, LR+, and LR− for vaginal involvement were 60%, 98%, 30.0, and 0.41. The sensitivity, specificity, LR+, and LR− for retrocervical involvement were 84%, 96%, 19.4, and 0.16. The sensitivity, specificity, and LR− for bladder involvement were 20%, 100%, and 0.80. The sensitivity, specificity, LR+, and LR− of the sliding sign for diagnosing pouch of Douglas obliteration were 89%, 92%, 10.7, and 0.12.

Conclusions

Except for bladder involvement, extended transvaginal sonography has good diagnostic performance for deep infiltrating endometriosis.
Fetal Left Ventricular Mass Determination on 2‐Dimensional Echocardiography Using Area‐Length Calculation Methods
Authors: Zheng Xiao-Zhi , Yang Bin , Wu Jing
Published: January 2014

Objectives

Fetal cardiac examination is an important part of fetal malformation screening. The purposes of this study were to describe the left ventricular (LV) mass in the second and third trimesters by 2‐dimensional echocardiography using area‐length calculation methods and to examine the clinical usefulness of this procedure in evaluation of gestational age (GA)‐ and fetal weight‐related LV mass changes.

Methods

Five hundred healthy fetuses were divided into 2 groups (250 participants per group): second‐ and third‐trimester groups. The estimated fetal weight (EFW) was computed according to the Hadlock formula (Radiology 1984; 150:535–540). The LV mass at end diastole (LVd mass) and LV mass at end systole (LVs mass) were measured, and the difference between the LVd mass and LVs mass [LV(d‐s) mass], LVd mass/EFW ratio, and LVs mass/EFW ratio were calculated.

Results

The EFW, LVd mass, LVs mass, and LV(d‐s) mass were all significantly greater in the third‐trimester group than the second‐trimester group (P < .05), whereas the LVd mass/EFW and LVs mass/EFW ratios did not differ between the groups (P > .05). The LVd mass, LVs mass, and LV(d‐s) mass all significantly correlated with GA and weight (P< .001), but the LVd mass/EFW and LVs mass/EFW ratios did not (P > .05).

Conclusions

Two‐dimensional echocardiography using area‐length calculation methods can effectively provide measurements for LV mass and can sensitively indicate fetal weight‐ and GA ‐related changes in LV mass. Fetal cardiac mass measurement is a useful parameter for evaluation of fetal heart development.
Variability and spatial fine structure of precipitating and trapped medium‐energy electron fluxes in the noon sector
Authors: Hargreaves J. K. , Birch M. J. , Evans D. S.
Published: January 2014

The relationships between the precipitating and trapped components of magnetospheric electron flux for energy ranges exceeding 30 and 100 keV have been investigated using data from polar orbiting satellites, the study being restricted to a limited geographic region at auroral latitudes in the noon sector. The electron flux of these energies is the cause of auroral radio absorption. The data are analyzed at two levels of detail. Variations between different passes are studied using their median values, and variations within passes are derived from individual data points at 2 s intervals, equivalent to about 10 km in distance. Several types of behavior are recognized. Basically, the ratio of precipitating to trapped flux at energies exceeding 30 keV varies in proportion to the trapped flux, though there is a limiting upper value where the two components are approximately equal. The precipitating flux never exceeds the trapped flux by any significant amount. These types appear to be consistent with weak and strong pitch angle scatterings, respectively. The precipitation at >100 keV varies somewhat with the >100 keV trapped flux but more strongly with the >30 keV component, consistent with scattering by chorus waves produced by electrons less energetic than those being scattered. Comparison between the two energy ranges shows that the precipitating component is always softer than the trapped. The detailed relationship between the precipitating and trapped components varies from pass to pass by an amount related to the east‐west component of the interplanetary magnetic field. Superimposed on the above behavior are large reductions of precipitation, spatial rather than temporal in nature, during which the trapped flux remains virtually unchanged. These reductions appear to be due to structures some tens of kilometers across, perhaps related to “ducts” within the magnetosphere. Some theoretical considerations based on the Kennel and Petscheck theory of scattering are given in an Appendix.
A two‐way nested simulation of the oceanic circulation in the Southwestern Atlantic
Authors: Combes Vincent , Matano Ricardo P.
Published: January 2014

This article presents the results of a high‐resolution (1/12°), two‐way nested simulation of the oceanic circulation in the southwestern Atlantic region. A comparison between the model results and extant observations indicates that the nested model has skill in reproducing the best‐known aspects of the regional circulation, e.g., the volume transport of the ACC, the latitudinal position of the BMC, the shelf break upwelling of Patagonia, and the Zapiola Anticyclone. Sensitivity experiments indicate that the bottom stress parameterization significantly impacts the mean location of the Brazil/Malvinas Confluence and the transport of the Zapiola Anticyclone. The transport of the Brazil Current strengthens during the austral summer and weakens during the austral winter. These variations are driven by the wind stress curl over the southwestern Atlantic. The variations of the transport of the Malvinas Current are out of phase with those of the Brazil Current. Most of the seasonal variability of this current is concentrated in the offshore portion of the jet, the inshore portion has a weak seasonality that modulates the magnitude of the Patagonian shelf break upwelling. Using passive tracers we show that most of the entrainment of deep waters into the shelf occurs in the southernmost portion of the Patagonian shelf and along the inshore boundary of the Brazil Current. Shelf waters are preferentially detrained near the Brazil/Malvinas Confluence. Consistent with previous studies, our simulation also shows that south of ∼42°S the Malvinas Current is composed of two jets, which merge near 42°S to form a single jet farther north.
Spectra and waveforms of ELF transients in the Earth‐ionosphere cavity with small losses
Authors: Nickolaenko A. P. , Hayakawa M.
Published: January 2014

Spectra and the waveforms are computed of the pulsed radio signals arriving from different distances to an observer in the Earth‐ionosphere cavity with the single‐scale exponential profile of air conductivity. The data were obtained for the cavity with exceptionally small losses. Spectra are compared of the signals in the realistic and an idealistic Earth‐ionosphere cavities. The waveforms are computed for such cavities and the pulse propagation velocities are evaluated. Studies of the Schumann resonance started from the ideal cavity model. Subsequent works dealt with the realistic propagation parameters and the ionosphere models on the Earth and other planets. However, the case of small losses is missing in the literature. We model ELF radio signals in such a cavity and demonstrate their noticeable distinctions from the customary records. In particular, the sinusoidal signals do not appear in the cavity with small losses, and instead, we obtain the sharp and large pulses. Computations show that the waveform propagating in the spherical cavity expands in time and reduces in amplitude. The time domain pulsed amplitudes were found at the source antipode and at the source point for the round‐the‐world wave. The latter becomes rather small even in the cavity with minor losses, so that autotriggering is unrealistic of a consecutive lightning discharge by the round‐the‐world echo even in a cavity with minor losses.
The Science Behind Laboratory‐Scale Models of the Earth
Authors: Leever Karen , Galland Olivier , Acocella Valerio
Published: January 2014

Deformation processes involve systems of tens to hundreds of kilometers moving at highly variable rates. Because direct kinematic observations have proven difficult, geoscientists are sometimes found in the lab creating analogs, or laboratory models of the Earth. The main scope—and a key challenge—of laboratory modeling of Earth systems is to provide a quantitative approach for understanding geological processes. Since the last decade, various image analysis techniques in laboratory modeling have been designed and used to constrain the kinematics of the simulated processes at an unprecedented resolution. These techniques prove to be the key quantification tools in experimental modeling, not only allowing mechanical analysis of the experiments but also producing experimental data sets that are directly comparable to geophysical and geodetic data in nature and numerical models.
A DNA Device that Mediates Selective Endosomal Escape and Intracellular Delivery of Drugs and Biologicals
Authors: Muro Silvia
Published: January 2014

Design of materials to aid intracellular delivery of agents can greatly improve medical treatments. While DNA is a molecule difficult to introduce into cells, DNA can be engineered into devices capable of intracellular delivery. However, transport mediated by DNA devices void of other structural materials, with sizes greater than that associated with non‐specific penetration, and a targeting capacity enough to overcome non‐specific pathways has not yet been achived. This study demonstrates that this is possible. Submicrometer (200 nm) dendrimers built of DNA (nucleodendrimers (NDs)) are coupled to antibodies against selected cell‐surface receptors and compared to polymer nanoparticles (NPs). NDs and NPs bind specifically to cells expressing these targets and efficiently enter cells via the pathway associated with the selected receptor. While NPs traffic to perinuclear endo‐lysosomes, NDs remain scattered throughout the cell, suggesting endosomal escape. This is confirmed in vitro, where NDs disrupt membranous vesicles at endosomal‐like pH and in cell culture, where they provide endosomal escape of model drugs, sugars, proteins, and nucleic acids; allow access to other intracellular compartments; result in measurable effects of cargoes, and; do not cause cytotoxicity. Therefore, these DNA nanodevices can be used to selectively overcome intracellular barriers, underscoring the growing range of applications of DNA materials.
Near‐Infrared Light Photovoltaic Detector Based on GaAs Nanocone Array/Monolayer Graphene Schottky Junction
Authors: Luo Lin‐Bao , Chen Jing‐Jing , Wang Ming‐Zheng , Hu Han , Wu Chun‐Yan , Li Qiang , Wang Li , Huang Jian‐An , Liang Feng‐Xia
Published: January 2014

Near infrared light photodiodes have been attracting increasing research interest due to their wide application in various fields. In this study, the fabrication of a new n‐type GaAs nanocone (GaAsNCs) array/monolayer graphene (MLG) Schottky junction is reported for NIR light detection. The NIR photodetector (NIRPD) shows obvious rectifying behavior with a turn‐on voltage of 0.6 V. Further device analysis reveals that the photovoltaic NIRPDs are highly sensitive to 850 nm light illumination, with a fast response speed and good spectral selectivity at zero bias voltage. It is also revealed that the NIRPD is capable of monitoring high‐switching frequency optical signals (∼2000 Hz) with a high relative balance. Theoretical simulations based on finite difference time domain (FDTD) analysis finds that the high device performance is partially associated with the optical property, which can trap most incident photons in an efficient way. It is expected that such a self‐driven NIRPD will have potential application in future optoelectronic devices.
Novel Meso‐Superstructured Solar Cells with a High Efficiency Exceeding 12%
Authors: Hu Yun Hang
Published: January 2014

The dye‐sensitized solar cell (DSSC) is representative of next generation photovoltaic devices. State‐of‐the‐art DSSCs have been established for two decades. However, the recent application of organic‐inorganic hybrid perovskites on nanoparticle Al2O3 film has totally changed the DSSC structure, leading to a new type of solar cell — meso‐superstructured solar cells (MSSCs) with a high power conversion efficiency exceeding 12%. This article summarizes this impressive progress and discusses the challenges of MSSCs.
Safety and efficacy of topical bacteriophage and ethylenediaminetetraacetic acid treatment of Staphylococcus aureus infection in a sheep model of sinusitis
Authors: Drilling Amanda , Morales Sandra , Boase Samuel , Jervis‐Bardy Joshua , James Craig , Jardeleza Camille , Tan Neil Cheng‐Wen , Cleland Edward , Speck Peter , Vreugde Sarah , Wormald Peter‐John
Published: January 2014

Background

Treatment of sinonasal bacterial biofilms continues to be a challenge in modern rhinology. This study's objective was to assess the safety and efficacy of topically applied Cocktail of S. aureus specific phage (CTSA) alone and in combination with ethylenediaminetetraacetic acid (EDTA) for treatment of Staphylococcus aureus biofilms in vivo.

Methods

Using a sheep model of sinusitis, frontal sinuses (n = 6 per treatment) were flushed once daily with a CTSA (2 × 106 plaque forming units [PFU]/mL), with or without EDTA (0.075 mg/mL), and compared to a control flush containing saline and heat‐inactivated CTSA. Safety was assessed using histology and scanning electron microscopy (SEM) after treatment for 3 days. Efficacy was assessed by quantifying the generation of S. aureus biofilms in the frontal sinuses after 5 days of treatment. Biofilm mass was compared between treatment groups and controls using LIVE/DEAD BacLight staining and confocal scanning laser microscopy to visualize the tissue sections. COMSTAT2 software was used to compute the biofilm mass present on tissue sections.

Results

Tissue morphology was conserved, with no significant signs of inflammation, when comparing control and test treatments. Furthermore, SEM analysis indicated test treatments were not toxic or damaging to mucosal cilia. COMSTAT2 quantification of biofilm showed a significant reduction in biofilm levels when comparing the control with CTSA (p = 0.0043), EDTA (p = 0.0095), and CTSA‐EDTA (p = 0.0022) treatments.

Conclusion

Results indicate that CTSA and EDTA are safe and efficacious for short‐term topical application against S. aureus infection in a sheep sinusitis model, and have the potential to be translated to a clinical setting.
Conductive olfactory losses in chronic rhinosinusitis? A computational fluid dynamics study of 29 patients
Authors: Zhao Kai , Jiang Jianbo , Pribitkin Edmund A. , Dalton Pamela , Rosen David , Lyman Brian , Yee Karen K. , Rawson Nancy E. , Cowart Beverly J.
Published: January 2014

Background

Besides sensorineural factors, conductive impediments likely contribute to olfactory losses in chronic rhinosinusitis (CRS) patients, yet no conclusive evidence exists. We aimed to examine possible conductive factors using computational fluid dynamics (CFD) models.

Methods

A total of 29 CRS patients were assessed via odorant detection thresholds (ODTs), rhinomanometry (nasal resistance [NR]), acoustic rhinometry (minimum‐cross‐sectional area [MCA]) and computed tomography (CT) staging. CFD simulations of nasal airflow and odorant absorption to olfactory region were carried out based on individual CTs. Biopsies of olfactory epithelium (OE) were collected, cryosectioned, stained, and scored for erosion.

Results

Significant correlations to ODTs were found for 3 variables: odor absorption in the olfactory region (r = −0.60, p < 0.01), MCA (r = −0.40, p < 0.05), and CT staging (r = 0.42, p < 0.05). However, significant findings were limited to ODTs of the highly soluble l‐carvone. Multiple regression analysis revealed that these variables combined, with the addition of NR, can account for 65% of the total variance in ODTs. CT staging correlated significantly with OE erosion (r = 0.77, p < 0.01) and can replace the latter in the regression with comparable outcomes. Partial correlations suggest the contributions of both conductive and sensorineural variables are more prominent if adjusted for the effects of the other. Olfactory loss and inflammatory factors have strong bilateral involvement, whereas conductive factors are independent between sides. As validation, CFD‐simulated NRs significantly correlated with rhinomanometrically assessed NRs (r = 0.60, p < 0.01).

Conclusion

Both conductive and sensorineural mechanisms can contribute to olfactory losses in CRS. CFD modeling provides critical guidance in understanding the role of conductive impediments in olfactory dysfunction in CRS.
The safety and efficacy of short‐term budesonide delivered via mucosal atomization device for chronic rhinosinusitis without nasal polyposis
Authors: Thamboo Andrew , Manji Jamil , Szeitz András , Santos Rachelle Dar , Hathorn Iain , Gan Eng Cern , Alsaleh Saad , Javer Amin R.
Published: January 2014

Background

Budesonide is a potent corticosteroid commonly prescribed for management of inflammation in chronic rhinosinusitis (CRS). The standard for prescribing budesonide is via impregnated nasal saline irrigation (INSI), although recently the mucosal atomization device (MAD) has emerged as a theoretically superior method of distributing medication into the sinuses. The MAD atomizes medication into small droplets and this is thought to enhance absorption and improve bioavailability. However, no studies have shown whether enhanced absorption and improved bioavailability of budesonide via MAD causes adrenal suppression. The objective of this study is to determine whether budesonide via MAD affects the hypothalamic‐pituitary‐adrenal (HPA) axis.

Methods

Twenty CRS patients were recruited from a tertiary rhinology clinic and randomized to take budesonide (1 mg) via MAD or via INSI twice a day for 60 days. The adrenocorticotropic hormone (ACTH) stimulation test and 22‐item Sinonasal Outcomes Test (SNOT‐22) questionnaire were administered on days 1, 30, and 60 of the study. Plasma budesonide and cortisol levels were simultaneously quantified using a high‐performance liquid chromatography–tandem mass spectrometry technique.

Results

There was no indication of adrenal suppression in either group (n = 20) based on ACTH stimulation test results nor was there significant plasma budesonide levels detected in either group. Quality of life, as indicated by SNOT‐22, did not differ between groups at 60 days (p = 0.404; 95% confidence interval [CI], −37.2 to 15.9), but SNOT‐22 scores for patients using MAD did show statistically significant improvement at 60 days compared to baseline (p = 0.02).

Conclusion

The MAD is likely a safe and effective method of delivering budesonide to the sinuses in the short term.
Markers of disease severity and socioeconomic factors in allergic fungal rhinosinusitis
Authors: Miller Justin D. , Deal Allison M. , McKinney Kibwei A. , McClurg Stanley W. , Rodriguez Kenneth D. , Thorp Brian D. , Senior Brent A. , Zanation Adam M. , Ebert Charles S.
Published: January 2014

Background

Allergic fungal rhinosinusitis (AFRS) is a refractory subtype of chronic rhinosinusitis. There is a paucity of data investigating the association of epidemiologic markers of disease severity. The primary objective of this study is to evaluate components of disease severity with socioeconomic status and health care access.

Methods

A retrospective analysis was performed on patients diagnosed with AFRS by Bent and Kuhn criteria from 2000 to 2013. Severity of disease was measured by orbitocranial involvement, bone erosion, Lund‐Mackay score, serum immunoglobulin E (IgE), and mold hypersensitivity. The North Carolina State Data Center provided county‐specific socioeconomic and demographic data. Fisher's exact test, Wilcoxon rank sum test, Pearson correlations, and multivariable linear regression models were used to explore associations between variables.

Results

Of 93 patients, 58% were African American and 39% Caucasian with a male:female ratio of 1.4:1 and average age at presentation of 29 years. Race, age, insurance status, and gender were not associated with severity of disease. Bone erosion was correlated with residence in counties with lower income per capita (p = 0.01). Patients with orbitocranial involvement resided in more rural counties (p = 0.01) with less primary care providers per capita (p = 0.02). Residence in counties with older or poorer quality housing was associated with a higher prevalence of bone erosion (p = 0.02).

Conclusion

Within our cohort of patients residing in North Carolina, markers of disease severity (bone erosion and orbitocranial involvement) in AFRS were associated with lower income, rural counties, poor housing quality, and less health care access.
Biosynthesis of Streptolidine Involved Two Unexpected Intermediates Produced by a Dihydroxylase and a Cyclase through Unusual Mechanisms
Authors: Chang Chin‐Yuan , Lyu Syue‐Yi , Liu Yu‐Chen , Hsu Ning‐Shian , Wu Chih‐Chung , Tang Cheng‐Fong , Lin Kuan‐Hung , Ho Jin‐Yuan , Wu Chang‐Jer , Tsai Ming‐Daw , Li Tsung‐Lin
Published: January 2014

Streptothricin‐F (STT‐F), one of the early‐discovered antibiotics, consists of three components, a β‐lysine homopolymer, an aminosugar D‐gulosamine, and an unusual bicyclic streptolidine. The biosynthesis of streptolidine is a long‐lasting but unresolved puzzle. Herein, a combination of genetic/biochemical/structural approaches was used to unravel this problem. The STT gene cluster was first sequenced from a Streptomyces variant BCRC 12163, wherein two gene products OrfP and OrfR were characterized in vitro to be a dihydroxylase and a cyclase, respectively. Thirteen high‐resolution crystal structures for both enzymes in different reaction intermediate states were snapshotted to help elucidate their catalytic mechanisms. OrfP catalyzes an FeII‐dependent double hydroxylation reaction converting L‐Arg into (3R,4R)‐(OH)2‐L‐Arg via (3S)‐OH‐L‐Arg, while OrfR catalyzes an unusual PLP‐dependent elimination/addition reaction cyclizing (3R,4R)‐(OH)2‐L‐Arg to the six‐membered (4R)‐OH‐capreomycidine. The biosynthetic mystery finally comes to light as the latter product was incorporation into STT‐F by a feeding experiment.
Asymmetric Hydrogenation with Iridium C,N and N,P Ligand Complexes: Characterization of Dihydride Intermediates with a Coordinated Alkene
Authors: Gruber Stefan , Pfaltz Andreas
Published: January 2014

Previously elusive iridium dihydride alkene complexes have been identified and characterized by NMR spectroscopy in solution. Reactivity studies demonstrated that these complexes are catalytically competent intermediates. Additional H2 is required to convert the catalyst‐bound alkene into the hydrogenation product, supporting an IrIII/IrV cycle via an [IrIII(H)2(alkene)(H2)(L)]+ intermediate, as originally proposed based on DFT calculations. NMR analyses indicate a reaction pathway proceeding through rapidly equilibrating isomeric dihydride alkene intermediates with a subsequent slow enantioselectivity‐determining step. As in the classical example of asymmetric hydrogenation with rhodium diphosphine catalysts, it is a minor, less stable intermediate that is converted into the major product enantiomer.
[ReF6]2−: A Robust Module for the Design of Molecule‐Based Magnetic Materials
Authors: Pedersen Kasper S. , Sigrist Marc , Sørensen Mikkel A. , Barra Anne‐Laure , Weyhermüller Thomas , Piligkos Stergios , Thuesen Christian Aa. , Vinum Morten G. , Mutka Hannu , Weihe Høgni , Clérac Rodolphe , Bendix Jesper
Published: January 2014

A facile synthesis of the [ReF6]2− ion and its use as a building block to synthesize magnetic systems are reported. Using dc and ac magnetic susceptibility measurements, INS and EPR spectroscopies, the magnetic properties of the isolated [ReF6]2− unit in (PPh4)2[ReF6]⋅2 H2O (1) have been fully studied including the slow relaxation of the magnetization observed below ca. 4 K. This slow dynamic is preserved for the one‐dimensional coordination polymer [Zn(viz)4(ReF6)]∞ (2, viz=1‐vinylimidazole), demonstrating the irrelevance of low symmetry for such magnetization dynamics in systems with easy‐plane‐type anisotropy. The ability of fluoride to mediate significant exchange interactions is exemplified by the isostructural [Ni(viz)4(ReF6)]∞ (3) analogue in which the ferromagnetic NiII–ReIV interaction (+10.8 cm−1) dwarfs the coupling present in related cyanide‐bridged systems. These results reveal [ReF6]2− to be an unique new module for the design of molecule‐based magnetic materials.
Helical Propensity in an Intrinsically Disordered Protein Accelerates Ligand Binding
Authors: Iešmantavičius Vytautas , Dogan Jakob , Jemth Per , Teilum Kaare , Kjaergaard Magnus
Published: January 2014

Many intrinsically disordered proteins fold upon binding to other macromolecules. The secondary structure present in the well‐ordered complex is often formed transiently in the unbound state. The consequence of such transient structure for the binding process is, however, not clear. The activation domain of the activator for thyroid hormone and retinoid receptors (ACTR) is intrinsically disordered and folds upon binding to the nuclear coactivator binding domain (NCBD) of the CREB binding protein. A number of mutants was designed that selectively perturbs the amount of secondary structure in unbound ACTR without interfering with the intermolecular interactions between ACTR and NCBD. Using NMR spectroscopy and fluorescence‐monitored stopped‐flow kinetic measurements we show that the secondary structure content in helix 1 of ACTR indeed influences the binding kinetics. The results thus support the notion of preformed secondary structure as an important determinant for molecular recognition in intrinsically disordered proteins.
The Pauson–Khand Mechanism Revisited: Origin of CO in the Final Product
Authors: Lesage Denis , Milet Anne , Memboeuf Antony , Blu Jérôme , Greene Andrew E. , Tabet Jean‐Claude , Gimbert Yves
Published: January 2014

The mechanism of the Pauson–Khand reaction has been studied by mass spectrometry and it has been found, through ion‐molecule reaction with 13CO, that the carbon monoxide incorporated into the product cyclopentenone is one that has been retained within the complex. Theoretical and kinetic calculations support this finding, which provides a complementary explanation for the effect of Pauson–Khand promoters.
Supramolecular Assemblies by Charge‐Transfer Interactions between Donor and Acceptor Chromophores
Authors: Das Anindita , Ghosh Suhrit
Published: January 2014

We have collated various supramolecular designs that utilize organic donor–acceptor CT complexation to generate noncovalently co‐assembled structures including fibrillar gels, micelles, vesicles, nanotubes, foldamers, conformationally restricted macromolecules, and liquid crystalline phases. Possibly inspired by nature, chemists have extensively used hydrogen bonding as a tool for supramolecular assemblies of a diverse range of abiotic building blocks. As a structural motif, CT complexes can be compared to hydrogen‐bonded complexes in its directional nature and complementarities. Additional advantages of CT interactions include wider solvent tolerance and easy spectroscopic probing. Nevertheless the major limitation is their low association constant. This article shows different strategies have evolved over the years to overcome this drawback by reinforcing the CT interactions with auxiliary noncovalent forces without hampering the alternate stacking mode. Emerging reports on promising CT complexes in organic electronics are intimately related to various supramolecular designs that one can postulate based on donor–acceptor CT interactions.
Using an Organic Molecule with Low Triplet Energy as a Host in a Highly Efficient Blue Electrophosphorescent Device
Authors: Fan Cong , Zhu Liping , Liu Tengxiao , Jiang Bei , Ma Dongge , Qin Jingui , Yang Chuluo
Published: January 2014

To achieve high efficiencies in blue phosphorescent organic light‐emitting diodes (PhOLEDs), the triplet energies (T1) of host materials are generally supposed to be higher than the blue phosphors. A small organic molecule with low singlet energy (S1) of 2.80 eV and triplet energy of 2.71 eV can be used as the host material for the blue phosphor, [bis(4,6‐difluorophenylpyridinato‐N,C2′)iridium(III)] tetrakis(1‐pyrazolyl)borate (FIr6; T1=2.73 eV). In both the photo‐ and electro‐excited processes, the energy transfer from the host material to FIr6 was found to be efficient. In a three organic‐layer device, the maximum current efficiency of 37 cd A−1 and power efficiency of 40 Lm W−1 were achieved for the FIr6‐based blue PhOLEDs.
TMEDA in Iron‐Catalyzed Kumada Coupling: Amine Adduct versus Homoleptic “ate” Complex Formation
Authors: Bedford Robin B. , Brenner Peter B. , Carter Emma , Cogswell Paul M. , Haddow Mairi F. , Harvey Jeremy N. , Murphy Damien M. , Nunn Joshua , Woodall Christopher H.
Published: January 2014

The reactions of iron chlorides with mesityl Grignard reagents and tetramethylethylenediamine (TMEDA) under catalytically relevant conditions tend to yield the homoleptic “ate” complex [Fe(mes)3]− (mes=mesityl) rather than adducts of the diamine, and it is this ate complex that accounts for the catalytic activity. Both [Fe(mes)3]− and the related complex [Fe(Bn)3]− (Bn=benzyl) react faster with representative electrophiles than the equivalent neutral [FeR2(TMEDA)] complexes. FeI species are observed under catalytically relevant conditions with both benzyl and smaller aryl Grignard reagents. The X‐ray structures of [Fe(Bn)3]− and [Fe(Bn)4]− were determined; [Fe(Bn)4]− is the first homoleptic σ‐hydrocarbyl FeIII complex that has been structurally characterized.
Synthetic Multivalent Glycopeptide‐Lipopeptide Antitumor Vaccines: Impact of the Cluster Effect on the Killing of Tumor Cells
Authors: Cai Hui , Sun Zhan‐Yi , Chen Mei‐Sha , Zhao Yu‐Fen , Kunz Horst , Li Yan‐Mei
Published: January 2014

Multivalent synthetic vaccines were obtained by solid‐phase synthesis of tumor‐associated MUC1 glycopeptide antigens and their coupling to a Pam3Cys lipopeptide through click reactions. These vaccines elicited immune responses in mice without the use of any external adjuvant. The vaccine containing four copies of a MUC1 sialyl‐TN antigen showed a significant cluster effect. It induced in mice prevailing IgG2a antibodies, which bind to MCF‐7 breast tumor cells and initiate the killing of these tumor cells by activation of the complement‐dependent cytotoxicity complex.
Mechanism of the Asymmetric Hydrogenation of Exocyclic α,β‐Unsaturated Carbonyl Compounds with an Iridium/BiphPhox Catalyst: NMR and DFT Studies
Authors: Liu Yuanyuan , Gridnev Ilya D. , Zhang Wanbin
Published: January 2014

The mechanism of the asymmetric hydrogenation of exocyclic α,β‐unsaturated carbonyl compounds with the (aS)‐Ir/iPr‐BiphPhox catalyst was studied by NMR experiments and DFT computational analyses. Computed optical yields of the asymmetric hydrogenation proceeding by an iridium(I)/iridium(III) mechanism involving a transition state stabilized through two intramolecular hydrogen bonds are in good accordance with the experimental ee values.
Recent advances in bio‐sourced polymeric carbohydrate/nanotube composites
Authors: Liu Dagang , Zhang Ying , Sun Xun , Chang Peter R.
Published: January 2014

Nanotubes (NTs), especially carbon nanotubes (CNTs), have attracted much attention in recent years because of their large specific surface area, and their outstanding mechanical, thermal, and electrical properties. In this review we emphasize the development of fascinating properties of polymeric carbohydrate/CNT composites, particularly in terms of their mechanical and conductivity properties and potential applications. Many methods used to modify CNTs during preparation of polymeric carbohydrate/CNT composites are presented. Moreover, we also discuss the enhanced mechanical and electrical effectiveness when hybrid CNTs or halloysite nanotubes were incorporated into different carbohydrate polymer matrices. Finally, we give a future outlook for the development of polymeric carbohydrate/CNT composites as potential alternative materials for various applications including sensors, electroactive paper, electrodes, sorbents for environmental remediation, packaging film, specialty textile, and biomedical devices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40359.
The cell forming process of microcellular injection‐molded parts
Authors: Dong Guiwei , Zhao Guoqun , Guan Yanjin , Wang Guilong , Wang Xiaoxin
Published: January 2014

In this article, we studied the cell forming process of microcellular injection‐molded parts. Using a modified injection molding machine equipped with a Mucell® SCF delivery system, microcellular‐foamed acrylonitrile–butadiene–styrene parts with different shot sizes were molded. The cell structure on the fractured surfaces along the direction both vertical and parallel to melt flow in the molded parts was examined. The results showed that a regular spherical cells region and a distorted ellipsoidal cells region exist in the molded parts simultaneously. The length of the distorted cells region along the melt flow direction in the molded parts remained basically unchanged for different shot sizes and it is about 195 mm away from the flow front in this study's conditions. The cell formation mechanism was analyzed, two cell forming processes in microcellular injection molding, the “foam during filling” process and the “foam after filling” process, were proposed. It was also found that the melt pressure in the filling stage is the dominant factor affecting the cell forming process, and there is a critical melt pressure value in the filling stage, 20.9 MPa, as the dividing line of the two cell forming processes in this study. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40365.
Improvement in impact strength of modified cardanol‐bonded cellulose thermoplastic resin by adding modified silicones
Authors: Soyama Makoto , Kiuchi Yukihiro , Iji Masatoshi , Tanaka Shukichi , Toyama Kiyohiko
Published: January 2014

The impact strength of cellulose diacetate (CDA) bonded with a modified cardanol (3‐pentadecylphenoxy acetic acid: PAA) was greatly improved up to 9 kJ/m2 by adding a relatively small amount of modified silicones while suppressing a decrease in bending strength. In our recent research, this thermoplastic resin (PAA‐bonded CDA) exhibited high rigidity, glass transition temperature, and water resistance. However, its impact strength was insufficient for use in durable products. Therefore, silicones modified with polyether, amino, and epoxy groups were investigated as possible ways to improve the impact strength. The results show that adding polyether‐modified silicone (polyether silicone) with moderate polarity relative to PAA‐bonded CDA resulted in shearing deformation greatly enhances its impact strength while maintaining other properties, including glass transition temperature (Tg), water resistance, and thermoplasticity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40366.
Eco‐friendly, acrylic resin‐modified potassium silicate as water‐based vehicle for anticorrosive zinc‐rich primers
Authors: Goodarzi Iman Mirzaie , Farzam Mansour , Shishesaz Mohammad Reza , Zaarei Davood
Published: January 2014

Potassium silicate binder of zinc‐rich coating was modified by adding water‐based acrylic resin. Several series of coatings containing 5, 10, and 15 wt % of acrylic and acrylic/styrene binders were added to potassium silicate. The coatings were applied on steel and the corrosion resistance of coatings was evaluated by conventional methods such as electrochemical impedance spectroscopy, corrosion potential, salt spray, and scanning electron microscopy. The results indicated that the modification of silicate binder with acrylic and acrylic/styrene led to shortening the curing time, improved corrosion protection, better dispersion of zinc particles, and enhanced salt spray resistance of resultant coatings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40370.
Conformationally Restricted Aza‐Dipyrromethene Boron Difluorides (Aza‐BODIPYs) with High Fluorescent Quantum Yields
Authors: Jiao Lijuan , Wu Yayang , Ding Yin , Wang Sufan , Zhang Ping , Yu Changjiang , Wei Yun , Mu Xiaolong , Hao Erhong
Published: January 2014

A simple approach to the highly fluorescent near‐infrared aza‐BODIPY dyes with higher fluorescence quantum yields (up to 0.81 in toluene) in comparison with their known analogues is presented. Our approach is based on the restricted rotations of the 1,7‐phenyl groups to the mean plane of the aza‐BODIPYs, which is achieved through the installation of bulky substituents on the 1,7‐phenyl groups of aza‐BODIPYs and results in a reduced nonradiative relaxation process in solution. The large torsion angles between the 1,7‐phenyl groups and the aza‐BODIPY core (ϕ1 and ϕ2 in these novel conformationally restricted aza‐BODIPYs) were confirmed by X‐ray diffraction studies.
Self‐Assembly of π‐Conjugated Gelators into Emissive Chiral Nanotubes: Emission Enhancement and Chiral Detection
Authors: Wang Xiufeng , Duan Pengfei , Liu Minghua
Published: January 2014

A series of new π‐conjugated gelators that contain various aromatic rings (phenyl, naphthyl, 9‐anthryl) and amphiphilic L‐glutamide was designed, and their gel formation in organic solvents and self‐assembled nanostructures was investigated. The gelators showed good gelation ability in various organic solvents that ranged from polar to nonpolar. Those gelator molecules with small rings such as phenyl and naphthyl self‐assembled into nanotube structures in most organic solvents and showed strong blue emission. However, the 9‐anthryl derivative formed only a nanofiber structure in any organic solvent, probably owing to the larger steric hindrance. All of these gels showed enhanced fluorescence in organogels. Furthermore, during the gel formation, the chirality at the L‐glutamide moiety was transferred to the nanostructures, thus leading to the formation of chiral nanotubes. One of the nanotubes showed chiral recognition toward the chiral amines.
Bridge‐Localized HOMO‐Binding Character of Divinylanthracene‐Bridged Dinuclear Ruthenium Carbonyl Complexes: Spectroscopic, Spectroelectrochemical, and Computational Studies
Authors: Ou Ya‐Ping , Zhang Jing , Xu Meng , Xia Jianlong , Hartl František , Yin Jun , Yu Guang‐Ao , Liu Sheng Hua
Published: January 2014

The electronic properties of four divinylanthracene‐bridged diruthenium carbonyl complexes [{RuCl(CO)(PMe3)3}2(μCHCHArCHCH)] (Ar=9,10‐anthracene (1), 1,5‐anthracene (2), 2,6‐anthracene (3), 1,8‐anthracene (4)) obtained by molecular spectroscopic methods (IR, UV/Vis/near‐IR, and EPR spectroscopy) and DFT calculations are reported. IR spectroelectrochemical studies have revealed that these complexes are first oxidized at the noninnocent bridging ligand, which is in line with the very small ν(CO) wavenumber shift that accompanies this process and also supported by DFT calculations. Because of poor conjugation in complex 1, except oxidized 1+, the electronic absorption spectra of complexes 2+, 3+, and 4+ all display the characteristic near‐IR band envelopes that have been deconvoluted into three Gaussian sub‐bands. Two of the sub‐bands belong mainly to metal‐to‐ligand charge‐transfer (MLCT) transitions according to results from time‐dependent DFT calculations. EPR spectroscopy of chemically generated 1+–4+ proves largely ligand‐centered spin density, again in accordance with IR spectra and DFT calculations results.
Identification and analysis of novel R308K mutation in glucokinase of type 2 diabetic patient and its kinetic correlation
Authors: Yellapu Nanda Kumar , Valasani Koteswara Rao , Pasupuleti Santhosh Kumar , Gopal Sowjenya , Potukuchi Venkata Gurunadha Krishna Sarma , Matcha Bhaskar
Published: January 2014

Glucokinase (GK) plays a critical role in glucose homeostasis and the mutations in GK gene result in pathogenic complications known as Maturity Onset Diabetes of the Young 2, an autosomal dominant form of diabetic condition. In the present study, GK was purified from human liver tissue and the pure enzyme showed single band in SDS‐PAGE with a molecular weight of 50 kDa. The kinetics of pure GK showed enzyme activity of 0.423 ± 0.02 µM glucose‐6‐phosphate (G6P)/mL/Min and Km value of 6.66 ± 0.02 µM. These values were compared in the liver biopsy of a clinically proven type 2 diabetic patient, where GK kinetics showed decreased enzyme activity of 0.16 ± 0.025 µM G6P/mL/Min and increased Km of 23 ± 0.9 µM, indicating the hyperglycemic condition in the patient. The genetic analysis of 10th exon of GK gene from this patient showed a R308K mutation. To substantiate these results, comparative molecular dynamics and docking studies were carried out where a higher docking score (−10.218 kcal/mol) was observed in the mutated GK than wild‐type GK structure (−12.593 kcal/mol) indicating affinity variations for glucose. During the simulation process, glucose was expelled out from the mutant conformation but not from wild‐type GK, making glucose unavailable for phosphorylation. Therefore, these results conclusively explain hyperglycemic condition in this patient.
High‐throughput ion exchange purification of positively charged recombinant protein in the presence of negatively charged dextran sulfate
Authors: Markely Lam Raga A. , Kurt Lutfiye , Lau Janet , Mane Sarthak , Guan Bing , Ryll Thomas , Estes Scott , Prajapati Shashi , Bakhshayeshi Meisam , Pieracci John
Published: January 2014

Product quality analyses are critical for developing cell line and bioprocess producing therapeutic proteins with desired critical product quality attributes. To facilitate these analyses, a high‐throughput small‐scale protein purification (SSP) is required to quickly purify many samples in parallel. Here we develop an SSP using ion exchange resins to purify a positively charged recombinant growth factor P1 in the presence of negatively charged dextran sulfate supplemented to improve the cell culture performance. The major challenge in this work is that the strong ionic interaction between P1 and dextran sulfate disrupts interaction between P1 and chromatography resins. To solve this problem, we develop a two‐step SSP using Q Sepharose Fast Flow (QFF) and SP Sepharose XL (SPXL) resins to purify P1. The overall yield of this two‐step SSP is 78%. Moreover, the SSP does not affect the critical product quality attributes. The SSP was critical for developing the cell line and process producing P1. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:516–520, 2014
Redox‐Driven Host–Guest Interactions Allow the Controlled Release of Captured Cells on RGD‐Functionalized Surfaces
Authors: Thakar Dhruv , Coche‐Guérente Liliane , Claron Michaël , Wenk Christiane H. F. , Dejeu Jérôme , Dumy Pascal , Labbé Pierre , Boturyn Didier
Published: January 2014

A quartz crystal microbalance technique with dissipation monitoring and a complementary optical microscopy technique were used for monitoring the capture and release of specific cells on a surface displaying a bifunctional molecular device, composed of a molecular scaffold endowed with the cell recognition property of an RGD ligand and a β‐CD/Fc redox‐switchable system.