bluuebunny/crossref_metadata_2025_split huggingface dataset:
Occupational hazards of endoscopic surgery
Authors: Little Rachel M. , Deal Allison M. , Zanation Adam M. , McKinney Kibwei , Senior Brent A. , Ebert Charles S. 
Published: December 2011

AbstractBackground:Minimally invasive surgery has taken its toll on the physical well‐being of surgeons. There have been many physical consequences for surgeons. However, few have been investigated, specifically for otolaryngologists performing endoscopic endonasal surgery (EES). The purpose of this study is to define the prevalence, quality, and severity of physical symptoms that otolaryngologists experience as they relate to the surgeons' use of ergonomically designed endoscopic instruments in endonasal surgery.Methods:A 25‐question survey was administered between September 2010 and March 2011 to practicing otolaryngologists. The questions addressed demographics, physical symptoms, ergonomics, and operating room environment. Data were analyzed using Fisher's exact, Wilcoxon rank sum, and Jonckheere‐Terpstra statistics.Results:Sixty‐two surgeons responded with a median age of 36 years. Responders performed a median of 150 EESs per year and 37% had completed an endoscopic fellowship. The majority (77%) of responders had experienced physical discomfort or symptoms that they attributed to EES. Thirteen percent (13%) of those who had experienced symptoms felt that their symptoms were persistent. Only 23% of those experiencing symptoms had sought medical care. No significant associations were seen between surgeon age, number of cases, standing, or having adjustable video display with experiencing discomfort (all p > 0.49). Interestingly, fewer surgeons completing an endoscopic fellowship experienced discomfort (70% vs 82%, p = 0.35).Conclusion:Our data showed that 77% of physicians who regularly perform EES suffer physical discomfort or symptoms attributable to EES. As expanded endonasal procedures become more prevalent, additional data and ergonomic analysis are necessary to reverse this trend and reduce possible long‐term damage for surgeons. © 2011 ARS‐AAOA, LLC.
Paranasal sinus and skull base fibro‐osseous lesions: when is biopsy indicated for diagnosis?
Authors: Efune Guy , Perez Carlos L. , Tong Liyue , Rihani Jordan , Batra Pete S. 
Published: December 2011

AbstractBackground:Paranasal sinus fibro‐osseous (FO) lesions represent a heterogeneous group, often sharing overlapping radiographic and pathologic features posing a dilemma in accurate diagnosis. The objective of this study was to correlate preoperative radiologic and postoperative histologic diagnosis to help guide a diagnostic algorithm.Methods:Retrospective analysis of 60 FO lesions between 1994 and 2010.Results:The mean age was 42.3 years with average follow‐up of 12.5 months. The preliminary radiologic diagnosis was osteoma in 22 (36.7%), fibrous dysplasia (FD) in 9 (15%), ossifying fibroma (OF) vs FD in 5 (8.3%), and OF in 3 (5%) cases. The diagnosis was indeterminate in 21 (35%) cases. Management consisted of excision in 29 (48.3%), observation in 17 (28.3%), and biopsy in 14 (23.3%) patients. For patients undergoing resection or biopsy, positive predictive value of preoperative radiology was 100% (10/10) for osteoma, 85.7% (6/7) for FD, and 33.3% (1/3) for OF cases. For the indeterminate lesions, most common pathologic diagnoses for 21 patients included osteoma in 4 (17.4%), arrested pneumatization in 3 (14.3%), OF in 3 (14.3%), and FD in 2 (9.5%). For FD vs OF cases, 3 underwent surgery, revealing osteoma, FD, and OF in 1 patient each.Conclusion:In this series, radiologic‐histopathologic correlation was high for osteoma and FD and low for OF and OF vs FD. This data suggests that patients with classic radiologic characteristics of osteoma and FD may be observed, unless resection is warranted based on clinical symptomatology. Preoperative diagnosis of OF, OF vs FD, or indeterminate lesions may warrant a biopsy to establish firm diagnosis to guide definitive management, especially if preoperative computed tomography (CT) imaging is concerning for an aggressive FO neoplasm. © 2011 ARS‐AAOA, LLC.
Targeted endoscopic salvage nasopharyngectomy for recurrent nasopharyngeal carcinoma
Authors: Ho Allen S. , Kaplan Michael J. , Fee Willard E. , Yao Mike , Sunwoo John B. , Hwang Peter H. 
Published: December 2011

AbstractBackground:Despite modern radiotherapy and open surgical techniques, treatment of recurrent nasopharyngeal carcinoma (NPC) remains challenging, with substantial morbidity involved. Targeted endoscopic nasopharyngectomy was evaluated as a viable oncologic alternative to open nasopharyngectomy or radiation for recurrent NPC.Methods:Thirteen patients who underwent endoscopic nasopharyngectomy for recurrent NPC between August 2005 and August 2010 were retrospectively reviewed. Average age at surgery was 55.7 years, with mean follow‐up period 24.2 months. Two‐year disease‐free survival, 2‐year overall survival, margin status, and complication rate were measured.Results:Including resections for subsequent recurrences, 19 endoscopic procedures were performed with curative intent. Mean operating room (OR) time was 278 minutes, mean estimated blood loss was 197 mL, and mean length of hospitalization was 1.0 days. Negative margins were obtained in 78.9% of procedures: positive margins involved the parapharyngeal space, oropharynx, fossa of Rosenmuller, and infratemporal fossa. Stereotactic radiation was given postoperatively for localized positive margins. Four patients required repeat endoscopic nasopharyngectomy for re‐recurrence, despite having their margins cleared or controlled with adjuvant treatment. Two‐year local disease‐free and overall survival rates were 69.2% and 100.0%, respectively. The overall minor complication rate was 52.6%, with no major complications.Conclusion:Targeted endoscopic nasopharyngectomy is beneficial in locally recurrent NPC, with favorable morbidity and complication rates. Endoscopic surveillance and serial imaging together facilitate the early identification of re‐recurrences, which often may be treated with additional directed resection. Postoperative stereotactic radiation may serve as an appropriate adjunct modality for disease control at positive margins. © 2011 ARS‐AAOA, LLC.
Chiral separation of D,L‐tyrosine through nitrocellulose membrane
Authors: Jiang Yun‐Dong , Zhang Jun‐Hui , Xie Sheng‐Ming , Lv Yin‐Chun , Zhang Mei , Ma Chao , Yuan Li‐Ming 
Published: December 2011

AbstractEnantioselective membrane was prepared using nitrocellulose as membrane material. The flux and permselective properties of membrane using water solution of D,L‐tyrosine as feed solution were studied. The top surface and cross‐section morphology of the resulting membrane were examined by scanning electron microscopy. The optical resolution of over 85% enantiomeric excess was achieved when the enantioselective membrane was prepared with 25 wt % nitrocellulose and 15 wt % N,N‐dimethylformamide in the casting solution of methanol, 10°C temperature of water bath for the gelation of the membrane, and the operating pressure and the feed concentration of the D,L‐tyrosine were 6 kgf/cm2 and 0.25 mg/mL, respectively. Since the nitrocellulose contains a large amount of chirality active carbons on the backbone structure and is possible to form helical structure, it is considered to be the reason for the enantioselectivity of the membrane. This is the first report that nitrocellulose can be used as a membrane material. This work indicates that the large‐scale purification of chiral molecules from racemic mixtures will be realized by the enantioselective membrane technique in the near future and that the enantioselective nitrocellulose membrane could soon become very attractive for industrial uses. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Modification and characterization of poly (ethylene terephthalate)‐grafted‐acrylic acid/acryl amide fiber for removal of lead from human plasma and environmental samples
Authors: Ahmad Panahi Homayon , Abdouss Majid , Ghiabi Frozan , Moniri Elham , Mousavi Shoushtari Ahmad 
Published: December 2011

AbstractA new fibrous adsorbent was prepared by grafting acrylic acid/acryl amide (AA/AAm) comonomers onto poly (ethylene terephthalate) (PET) fibers. The resulting sorbent has been characterized by Fourier transform infrared (FT‐IR), elemental analysis, thermogravimetric analysis (TGA), FT‐Raman, and scanning electron microscopy (SEM) and studied for the preconcentration and determination of trace Pb (II) ion from human biological fluid and environmental water samples. The optimum pH value for sorption of the metal ion was 8. The sorption capacity of functionalized resin is 44.1 mg g−1. The chelating sorbent can be reused for 20 cycles of sorption–desorption without any significant change in sorption capacity. A recovery of 100.2% was obtained for the metal ion with 0.5M nitric acid as eluting agent. Effect of grafting yield, shaking time, shape of sorbent, and pH of the medium on adsorption of the metal ion were investigated. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The equilibrium adsorption data of Pb (II) on modified fiber were analyzed by Langmuir, Freundlich, Temkin, and Redlich‐Peterson models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined as 0.236, 10.544, and 9.497 at pH 8 and 20°C, respectively. The method was applied for lead ions determination from human plasma and sea water sample. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Increased recycling of polyamines is associated with global DNA hypomethylation in rheumatoid arthritis synovial fibroblasts
Authors: Karouzakis Emmanuel , Gay Renate E. , Gay Steffen , Neidhart Michel 
Published: December 2011

AbstractObjectiveGlobal DNA hypomethylation in rheumatoid arthritis synovial fibroblasts (RASFs) contributes to their intrinsic activation. The aim of this study was to investigate whether increased polyamine metabolism is associated with a decreased level of S‐adenosyl methionine (SAM), causing global DNA hypomethylation.MethodsSynovial fibroblasts were isolated from synovial tissue obtained from 12 patients with RA and from 6 patients with osteoarthritis (OA). The cells were stained for S‐adenosyl methionine decarboxylase (AMD), spermidine/spermine N1‐acetyltransferase (SSAT1), polyamine‐modulated factor 1–binding protein 1 (PMFBP1), solute carrier family 3 member 2 (SLC3A2), DNA methyltransferase 1 (DNMT‐1), α9 integrin, and β1 integrin and analyzed by flow cytometry. Nuclear 5‐methylcytosine (5‐MeC) was measured by flow cytometry, the expression of diacetylspermine (DASp) in cell culture supernatants and cell extracts was determined by enzyme‐linked immunosorbent assay, and SAM expression in cell extracts was measured by fluorometry.ResultsThe expression of SSAT1, AMD, and PMFBP1 was significantly increased in RASFs compared with OASFs. The expression of DASp in cell culture supernatants and the expression of SLC3A2 were significantly elevated in RASFs. The levels of SAM in cell culture extracts, as well as the levels of DNMT‐1 protein and 5‐MeC, were significantly reduced in RASFs. Parameters of polyamine metabolism were negatively correlated with the expression of SAM, DNMT‐1, and 5‐MeC.ConclusionThese data clearly show that intrinsic elevations of PMFBP1 and SSAT1 enhance the catabolism and recycling of polyamines in RASFs and suggest that high consumption of SAM via this pathway is an important factor contributing to global DNA hypomethylation in these cells.
Interactions of surfactants with a water treatment protein from Moringa oleifera seeds in solution studied by zeta‐potential and light scattering measurements
Authors: Kwaambwa Habauka M. , Rennie Adrian R. 
Published: December 2011

AbstractProtein extracted from Moringa oleifera (MO) seeds has been advocated as a cheap and environmental friendly alternative to ionic flocculants for water purification. However, the nature and mechanism of its interaction with particles in water, as well as with dissolved surface‐active molecules, are not well understood. In this article, we report studies of the protein and its interaction with four surfactants using dynamic light scattering (DLS), zeta‐potential and turbidity measurements. Zeta‐potential measurements identified points of charge reversal and the turbidity and DLS measurements were used to characterize the microstructure and size of protein‐surfactant complexes. From the points of charge reversal, it was estimated that 7 anions are required to neutralize the positive charges of each protein molecule at pH 7. For protein mixtures with sodium dodecyl sulfate and dodecyl di‐acid sodium salt, the peak in turbidity corresponds to concentrations with a large change in zeta‐potential. No turbidity was observed for protein mixtures with either the nonionic surfactant Triton X‐100 or the zwitterionic surfactant N‐dodecyl‐N,N‐dimethyl‐3‐ammonio‐1‐propanesulfonate. Changes of pH in the range 4–10 have little effect on the zeta‐potential, turbidity, and the hydrodynamic radius reflecting the high isoelectric point of the protein. Addition of small amounts of salt has little effect on the size of protein in solution. These results are discussed in the context of the use of the MO protein in water treatment. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 209–218, 2012.
Novel structures of self‐associating stapled peptides
Authors: Bhattacharya Shibani , Zhang Hongtao , Cowburn David , Debnath Asim K. 
Published: December 2011

AbstractHydrocarbon stapling of peptides is a powerful technique to transform linear peptides into cell‐permeable helical structures that can bind to specific biological targets. In this study, we have used high resolution solution NMR techniques complemented by dynamic light scattering to characterize extensively a family of hydrocarbon stapled peptides with known inhibitory activity against HIV‐1 capsid assembly to evaluate the various factors that modulate activity. The helical peptides share a common binding motif but differ in charge, the length, and position of the staple. An important outcome of the study was to show the peptides, share a propensity to self‐associate into organized polymeric structures mediated predominantly by hydrophobic interactions between the olefinic chain and the aromatic side‐chains from the peptide. We have also investigated in detail the structural significance of the length and position of the staple, and of olefinic bond isomerization in stabilizing the helical conformation of the peptides as potential factors driving polymerization. This study presents the numerous challenges of designing biologically active stapled peptides and the conclusions have broad implications for optimizing a promising new class of compounds in drug discovery. © 2011 Wiley Periodicals, Inc. Biopolymers 97: 253–264, 2012.
Transgene delivery using poly(amino ether)‐gold nanorod assemblies
Authors: Ramos James , Rege Kaushal 
Published: December 2011

AbstractGold nanorods (GNRs) have emerged as promising nanomaterials for biosensing, imaging, photothermal treatment, and therapeutic delivery for several diseases, including cancer. We have generated poly(amino ether)‐functionalized gold nanorods (PAE‐GNRs) using a layer‐by‐layer deposition approach; polymers from a poly(amino ether) library recently synthesized in our laboratory were employed to generate the PAE‐GNR assemblies. PAE‐GNR assemblies demonstrate long‐term colloidal stability as well as the capacity to bind plasmid DNA by means of electrostatic interactions. Sub‐toxic concentrations of PAE‐GNRs were employed to deliver plasmid DNA to prostate cancer cells in vitro. PAE‐GNRs generated using 1,4C‐1,4Bis, a cationic polymer from our laboratory demonstrated significantly higher transgene expression and exhibited lower cytotoxicities when compared to similar assemblies generated using 25 kDa poly(ethylene imine) (PEI25k‐GNRs), a current standard for polymer‐mediated gene delivery. The roles of polyelectrolyte chemistry and zeta‐potential in determining transgene expression efficacies of PAE‐GNR assemblies were investigated. Our results indicate that stable and effective PAE‐GNR assemblies are a promising engineered platform for transgene delivery. PAE‐GNRs also have the potential to be used simultaneously for photothermal ablation, photothermally enhanced drug and gene delivery, and biological imaging, thus making them a powerful theranostic platform. Biotechnol. Bioeng. 2012; 109:1336–1346. © 2011 Wiley Periodicals, Inc.
Target concentration dependence of DNA melting temperature on oligonucleotide microarrays
Authors: Ozel Ayse Bilge , Srivannavit Onnop , Rouillard Jean‐Marie , Gulari Erdogan 
Published: December 2011

AbstractThe design of microarrays is currently based on studies focusing on DNA hybridization reaction in bulk solution. However, the presence of a surface to which the probe strand is attached can make the solution‐based approximations invalid, resulting in sub‐optimum hybridization conditions. To determine the effect of surfaces on DNA duplex formation, the authors studied the dependence of DNA melting temperature (Tm) on target concentration. An automated system was developed to capture the melting profiles of a 25‐mer perfect‐match probe–target pair initially hybridized at 23°C. Target concentrations ranged from 0.0165 to 15 nM with different probe amounts (0.03–0.82 pmol on a surface area of 1018 Å2), a constant probe density (5 × 1012 molecules/cm2) and spacer length (15 dT). The authors found that Tm for duplexes anchored to a surface is lower than in‐solution, and this difference increases with increasing target concentration. In a representative set, a target concentration increase from 0.5 to 15 nM with 0.82 pmol of probe on the surface resulted in a Tm decrease of 6°C when compared with a 4°C increase in solution. At very low target concentrations, a multi‐melting process was observed in low temperature domains of the curves. This was attributed to the presence of truncated or mismatch probes. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Rapid Synthesis of New DNMT Inhibitors Derivatives of Procainamide
Authors: Halby Ludovic , Champion Christine , Sénamaud‐Beaufort Catherine , Ajjan Sophie , Drujon Thierry , Rajavelu Arumugam , Ceccaldi Alexandre , Jurkowska Renata , Lequin Olivier , Nelson William G. , Guy Alain , Jeltsch Albert , Guianvarc'h Dominique , Ferroud Clotilde , Arimondo Paola B. 
Published: December 2011

AbstractDNA methyltransferases (DNMTs) are responsible for DNA methylation, an epigenetic modification involved in gene regulation. Families of conjugates of procainamide, an inhibitor of DNMT1, were conceived and produced by rapid synthetic pathways. Six compounds resulted in potent inhibitors of the murine catalytic Dnmt3A/3L complex and of human DNMT1, at least 50 times greater than that of the parent compounds. The inhibitors showed selectivity for C5 DNA methyltransferases. The cytotoxicity of the inhibitors was validated on two tumour cell lines (DU145 and HCT116) and correlated with the DNMT inhibitory potency. The inhibition potency of procainamide conjugated to phthalimide through alkyl linkers depended on the length of the linker; the dodecane linker was the best.
Luminescent Organoplatinum(II) Complexes with Functionalized Cyclometalated C^N^C Ligands: Structures, Photophysical Properties, and Material Applications
Authors: Kui Steven C. F. , Hung Faan‐Fung , Lai Shiu‐Lun , Yuen Mai‐Yan , Kwok Chi‐Chung , Low Kam‐Hung , Chui Stephen Sin‐Yin , Che Chi‐Ming 
Published: December 2011

AbstractA series of [(R′‐C^N^C‐R′′)Pt(L)] complexes with doubly deprotonated cyclometalated R′‐C^N^C‐R′′ ligands (R′‐C^N^C‐R′′=2,6‐diphenylpyridine derivatives) functionalized with carbazole, fluorene, or thiophene unit(s) have been synthesized and their photophysical properties studied. The X‐ray crystal structures reveal extensive intermolecular π⋅⋅⋅π and CH⋅⋅⋅π interactions between the cyclometalated C^N^C ligands. Compared to previously reported cyclometalated platinum(II) complexes [(C^N^C)Pt(L)], which are non‐emissive in solution at room temperature, the carbazole‐, fluorene‐ and thiophene‐functionalized [(R′‐C^N^C‐R′′)Pt(L)] (L=DMSO 1–9, CNAr, 1 a–9 a) complexes are emissive in solution at room temperature with λmax at 564–619 nm and Φ=0.02–0.26. The emissions of the [(R′‐C^N^C‐R′′)Pt(L)] complexes are attributed to electronic excited states with mixed 3MLCT and 3IL character. The carbazole/fluorene/thiophene unit(s) allow the tuning of the electronic properties of the [(R′‐C^N^C‐R′′)Pt] moiety, with the emission maxima in a range of 564–619 nm. These are the first examples of organoplatinum(II) complexes bearing doubly deprotonated cyclometalated C^N^C ligands that are emissive in solution at room temperature. In non‐degassed DMSO, the emission intensities of 6 a–9 a are enhanced upon exposure to ambient light. This phenomenon is caused by reacting photogenerated 1O2 with a DMSO molecule to form dimethyl sulfone, leading to the removal of dissolved oxygen in solution. Self‐assembled nanowires and nanorods are obtained from precipitation of 3 a in THF/H2O and 8 a in DMSO/Et2O, respectively. The [(R′‐C^N^C‐R′′)Pt(L)] complexes are soluble in common organic solvents with a high thermal stability (>300 °C), rendering them as phosphorescent dopants for organic light‐emitting diode (OLEDs) applications. Red OLEDs with CIE coordinates of (0.65±0.01, 0.35±0.01) were fabricated from 7 a or 8 a. A maximum external efficiency (ηExt) of 12.6 % was obtained for the device using 8 a as emitter.
Activation of Diboron Reagents with Brønsted Bases and Alcohols: An Experimental and Theoretical Perspective of the Organocatalytic Boron Conjugate Addition Reaction
Authors: Pubill‐Ulldemolins Cristina , Bonet Amadeu , Bo Carles , Gulyás Henrik , Fernández Elena 
Published: December 2011

AbstractBases play an important role in organocatalytic boron conjugate addition reactions. The sole use of MeOH and a base can efficiently transform acyclic and cyclic activated olefins into the corresponding β‐borated products in the presence of diboron reagents. Inorganic and organic bases deprotonate MeOH in the presence of diboron reagents. It is concluded, on the basis of theoretical calculations, NMR spectroscopic data, and ESI‐MS experiments, that the methoxide anion forms a Lewis acid–base adduct with the diboron reagent. The sp2 B atom of the methoxide–diboron adduct gains a strongly nucleophilic character, and attacks the electron‐deficient olefin. The methanol protonates the intermediate, generating the product and another methoxide anion. This appears to be the simplest method to activate diboron reagents and make them suitable for incorporation into target organic molecules.
Computational and Experimental Evidence of Through‐Space NMR Spectroscopic J Coupling of Hydrogen Atoms
Authors: Dračínský Martin , Jansa Petr , Bouř Petr 
Published: December 2011

AbstractJ coupling in NMR spectroscopy is conventionally associated with covalent bonds. A noncovalent contribution often called through‐space coupling (TSC) has been observed for heavy atoms. In this study, the TSC was detected and analyzed for the more common 1H1H coupling as well. In synthesized model molecules the hydrogen positions could be well controlled. For several coupling constants the through‐space mechanism was even found to be the predominant factor. The nature and magnitude of the phenomenon were also analyzed by density functional computations. Calculated carbon‐ and hydrogen‐coupling maps and perturbed electronic densities suggest that the aromatic system strongly participates in the noncovalent contribution. Unlike covalent coupling, which is usually governed by the Fermi contact, TSC is dominated by the diamagnetic term comprising interactions of nuclei with the electron orbital angular momentum. The computations further revealed a strong distance and conformational dependence of TSC. This suggests that the through‐space coupling can be explored in molecular structural studies in the same way as the covalent one.