bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chondroid Syringoma at Tip of the Nose: A Rare Site
Authors: Dhanda Sunil Kumar 
Published: April 2012

ABSTRACT
Chondroid syringoma is an uncommon, benign, sweat gland tumor. The usual presentation is of an asymptomatic, slowly growing mass. Preoperative diagnosis is difficult and generally histopathology examination confirms the diagnosis. We report a case of chondroid syringoma in 24-year-old male for its rarity at the tip of the nose.
Hairy Polyp of Nasopharynx
Authors: Singh Digvijay , Daharwal Ajit , Banjara Hansa , Sarkar Sutanu 
Published: April 2012

ABSTRACT
Hairy polyps are rare benign congenital malformations occurring in the nasopharynx or oropharynx. They arise during early embryogenesis and are invariably benign. They usually present at or soon after birth with signs of airway obstruction or feeding difficulties. Hairy polyps rarely present in older patients and only few cases have been reported in adults. We report a case of hairy polyp of nasopharynx in a 22-year-old female.
Pyogenic Granuloma of Nasal Septum
Authors: Kulkarni Anuja Santosh 
Published: April 2012

ABSTRACT
Pyogenic granuloma also known as lobular capillary hemangioma is although rare but well-documented clinical entity. However, it is more commonly reported in cases pertaining to lesions of oral cavity and especially in female patients during pregnancy usually in third decade of life. But, here we report a very uncommon presentation of pyogenic granuloma arising from nasal septum in a 52-year-old male patient who presented to us with history of epistaxis and left-sided nasal obstruction since 4 months.
Squamous Cell Carcinoma of Nose: An Unusual Presentation
Authors: Mishra Aseem , Nagle Smita K , Oberoi Vikram , Jagade Mohan Vasant , Kasbekar Vimal 
Published: April 2012

ABSTRACT
Most commonly, a carcinoma of nose is a basal cell carcinoma and a squamous cell carcinoma commonly arise from the dorsum of the nose. We present here a case of 35-year-old female with a squamous cell carcinoma of the nasal vestibule, which started as a wart and was very slowly progressive, until it was excised by a practitioner in a village. It then progressed rapidly and presented to us. The mass appeared a squamous cell carcinoma arising from nasal vestibule. The wart-like presentation also associates the etiology of squamous cell carcinoma to human papilloma virus and the disadvantages of excision of mass without proper histopathological diagnosis. The case was successfully managed with wide local excision with reconstruction by buccal and Estlander's flap.
The Challenges of the Detection of Subclinical Keratoconus at Its Earliest Stage
Authors: Saad Alain 
Published: April 2012

ABSTRACT
Undetected subclinical keratoconus (KC) is the main risk factor for iatrogenic ectasia. Many parameters have been proposed to help differentiate normal from subclinical KC corneas. Linear discriminant analysis is a technique that models the difference between different classes of data by looking for linear combinations of variables which best explain the data. The association of surfaces elevation, corneal thickness profile and anterior curvature indices leads to the best sensitivity and specificity for the discrimination between normal and early subclinical KC corneas.

How to cite this article
Gatinel D, Saad A. The Challenges of the Detection of Subclinical Keratoconus at Its Earliest Stage. Int J Keratoco Ectatic Corneal Dis 2012;1(1):36-43.
Collagen Corneal Cross-Linking followed by Intac Implantation in a Case of Post-PRK Ectasia
Authors: Abdelaziz Lamis , Zadok David , Pikkel Joseph , Garzozi Hanna , Marcovich Arie , Nasser Orwa 
Published: April 2012

ABSTRACT
Collagen corneal cross-linking (CXL) has proved to be effective in halting the progression of keratoconus and post-LASIK ectasia.
Post-photorefractive keratectomy (PRK) ectasia, a rare PRK complication, has been reported in only a few cases, although PRK is the oldest form of laser refractive surgery. CXL for post- PRK ectasia has not been reported yet.
Here is a case of a 22-year-old male who developed post- PRK ectasia more than 1 year after the procedure and was treated using CXL. A few months after CXL, an Intac (Addition Technology) was implanted due to contact lens intolerance.

How to cite this article
Barbara R, Zadok D, Pikkel J, Marcovich A, Garzozi H, Nasser O, Abdelaziz L, Barbara A. Collagen Corneal Cross-Linking followed by Intac Implantation in a Case of Post-PRK Ectasia. Int J Keratoco Ectatic Corneal Dis 2012;1(1):68-72.
One‐Pot Hydroacetylation of Menadione (Vitamin K3) to Menadiol Diacetate (Vitamin K4) by Heterogeneous Catalysis
Authors: Dobrinescu Claudiu , Iorgulescu Elena E. , Mihailciuc Constantin , Macovei Dan , Wuttke Stefan , Kemnitz Erhard , Parvulescu Vasile I. , Coman Simona M. 
Published: April 2012

AbstractVitamin K4 (menadiol diacetate, MDD) can be easily synthesized through cleaner and more efficient catalytic alternatives following the green chemistry principles. Ionic gold‐based hydroxylated fluorides are active bi‐functional catalysts for the one‐pot hydroacetylation of menadione leading to MDD with 77% selectivity. Unprecedent results were obtained in the presence of oxide‐fluoride catalysts by using a microwave‐assisted hydrogen‐transfer (Meerwein–Ponndorf–Verley reaction) coupled with an acetylation approach, yielding very high selectivities for the target product (95%).
Modeling Nonlinearities in the U.S. Soybean‐to‐Corn Price Ratio: A Smooth Transition Autoregression Approach
Authors: Ubilava David 
Published: April 2012

ABSTRACTThe soybean‐to‐corn price ratio has long been considered one of the triggers that farmers use in the decision to produce corn or soybeans, but little has been done to analyze its dynamics. Recently, the soybean‐to‐corn price ratio options were introduced on the Chicago Board of Trade, providing the market participants with an opportunity to trade the relative prices of the crops. In this study, the author investigates potentially nonlinear dynamics of the soybean‐to‐corn price ratio by applying the smooth transition autoregression (STAR) modeling framework to the soybean‐to‐corn price ratio, derived from monthly futures prices of corn and soybeans. The estimated model demonstrates nonlinear dynamics, resulting in asymmetries in the adjustment to the long‐run equilibrium of the soybean‐to‐corn price ratio. The findings of this research provide insightful implications to crop producers, input suppliers, and other market participants.
Variable‐temperature Fourier transform infrared studies of matrix–nanofiller interactions in amorphous polyamide/layered silicate nanocomposites
Authors: Zhang Xingui , Loo Leslie S. 
Published: April 2012

AbstractVariable‐temperature Fourier transform infrared spectroscopy was used to investigate matrix–nanofiller interactions in amorphous semiaromatic polyamide/layered silicate nanocomposites prepared by melt intercalation. The types of polymer–nanofiller interactions were found to be strongly dependent on the nature of the polymer matrix and the surfactant‐modified layered silicate. Improved compatibility resulted when hydrogen‐bonding interactions occurred between the surfactant and polymer chains. The presence of surfactants with phenyl groups also led to a more stable molecular structure of the polymer matrix because of the enhanced resonance effect between aromatic groups. SiO stretching vibrations in the layered silicate shifted to lower wavenumbers with increasing temperature; this indicated the presence of weaker polymer‐layered silicate interactions. The results of this study demonstrate that for the polymer nanocomposites prepared by melting intercalation, more important interfacial interactions existed between the polymer and the surfactant. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation, characterization, and dyeing properties of calcium alginate fibers
Authors: Lv Fangbing , Zhu Ping , Wang Chaoxia , Zheng Limin 
Published: April 2012

AbstractA novel attempt has been investigated in this article to dye calcium alginate fibers with acid dyes. The calcium alginate fibers were prepared by wet spinning and their dyeing properties were studied. Scanning electron microscopy analysis revealed that the surface of calcium alginate fibers was relatively smooth and uniform with many small grooves. The X‐ray diffraction results indicated that the crystallinity of the fibers was 61%. The dyeing conditions were optimized by testing the exhaustion (%). Moreover, the kinetics of dyeing calcium alginate fibers was determined as a function of dyeing time with various acid dyes. The results also showed that the calcium alginate fibers exhibited good dyeability with the fastnesses to washing and dry rubbing around 4 grades. At the same time, the dyeing process had no significant influence on the mechanical properties of the fibers with the strength loss only around 0.3 cN/dtex. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation and properties of cyclic olefin copolymers multiwalled carbon nanotube nanocomposites
Authors: Chen Zhen‐hua , Zeng Changchun , Zhang Chuck , Wang Ben , Cao Kun , Yao Zhen 
Published: April 2012

AbstractNanocomposites of cyclic olefin copolymer (COC) and two types of multiwalled carbon nanotubes (MWCNTs) with different aspect ratios were prepared. The morphology, thermal behavior, and electrical conductivity of the nanocomposites were investigated by scanning electron microscopy, differential scanning calorimetry, thermal gravimetric analysis, and the DC conductivity measurement. It was found that the developed nanocomposite preparation method resulted in good nanotubes dispersion in the polymer matrix for both types of MWCNTs. No appreciable differences in glass transition temperatures were observed between the pure COC and nanocomposites. On the other hand, CNTs significantly improved the thermo‐oxidative stability of the COC. The nanocomposites showed significant delay in onset of degradation and the degradation temperature was ∼ 40°C higher than that of the pure COC. The nanocomposites also showed substantially higher DC conductivity, which increased with the nanotube concentration and aspect ratio. An increase of DC electrical conductivity over 109 times can be achieved by the addition of 2 wt % CNTs. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
An easy‐to‐obtain silicone‐containing flame retardant and its effects on the combustion of polycarbonate
Authors: Ding Liping , Song Rongjun , Li Bin 
Published: April 2012

AbstractA novel silicone‐containing flame retardant (HSOBA) synthesized from hydrogen‐containing silicone oil and Bisphenol A via a simple approach has been incorporated into polycarbonate (PC) matrix to study its effects on the flame retardancy. The flame retardancy of PC/HSOBA composites is investigated by limiting oxygen index (LOI), vertical burning tests (UL‐94), and cone calorimeter measurement. The LOI value of the composites is 31.7 and the UL‐94 rating reaches V‐0, when the content of HSOBA is 3 wt %. Cone calorimeter data confirm that the HSOBA acts as an effective additive functioning both as flame retardants and as smoke suppressant. Evolution of the thermal behaviors of the composites tested by TGA, the morphological structures, and the constituent of char residue after LOI tests characterized by scanning electronic microscopy‐energy‐dispersive X‐ray analysis were used to explain the possible flame‐retardant mode. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Sustained release of an antitumoral drug from alginate‐chitosan hydrogel beads and its potential use as colonic drug delivery
Authors: Torelli‐Souza Rebecca R. , Cavalcante Bastos Layanna A. , Nunes Hermano G. L. , Camara Celso A. , Amorim Rosa Valéria S. 
Published: April 2012

AbstractFew researches are directed at drug delivery systems for β‐lapachone (β‐lap), a powerful anticancer agent but with limited pharmaceutical use. To overcome its limitations, we investigated controlled delivery systems of β‐lap in simulated gastric fluids in vitro from chitosan (CS) and alginate (AL) hydrogel beads with purpose for oral administration. The AL‐CS hydrogel beads were formed by coacervation and were characterized by morphology, swelling ratio, and their physicochemical properties. The hydrogel beads, with sizes of roughly 1 mm, presented good stability, and low porosity. The in vitro drug release profile was in good agreement with kinetics profiles and the Fickian model indicating diffusion as the release mechanism, with low burst effect, especially in an acid medium and allowing a prolonged release of ∼ 72 h (pH 1.2; k2 = 0.19 ± 0.04) and (pH 7.4; k2 = 0.20 ± 0.01). The beads were resistant to the acid medium and may be an alternative for β‐lap therapy of colorectal cancer. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Heterocycles 27. Microwave Assisted Synthesis and Antitumour Activity of Novel Phenothiazinyl‐Thiazolyl‐Hydrazine Derivatives
Authors: Ignat Adriana , Lovasz Tamas , Vasilescu Mihai , Fischer‐Fodor Eva , Tatomir Corina Bianca , Cristea Castelia , Silaghi‐Dumitrescu Luminiţa , Zaharia Valentin 
Published: April 2012

AbstractA series of new phenothiazinyl‐thiazolyl‐hydrazine derivatives were synthesized by Hantzsch cyclization of 1‐(10‐ethyl‐10H‐phenothiazin‐3‐yl)‐methylidene‐thiosemicarbazide with α‐halocarbonyl derivatives. Comparison between classical and microwave assisted synthesis emphasizes the great advantages induced by microwaves irradiation which afforded high reaction yields in much shorter reaction time. Structural assignments were based on spectroscopic methods (high resolution NMR, FTIR, MS). The new compounds were tested in vitro for their antiproliferative activity against tumor cell lines using spectrometric methods. Most of the compounds exhibit cytotoxicity against hepatic and colon tumor cells in a dose‐dependent mode and a relationship between the structure and their biological activity was observed.
2‐Benzazepine Nitrones Protect Dopaminergic Neurons against 6‐Hydroxydopamine‐Induced Oxidative Toxicity
Authors: Soto‐Otero Ramón , Méndez‐Álvarez Estefanía , Sánchez‐Iglesias Sofía , Labandeira‐García José Luís , Rodríguez‐Pallares Jannette , Zubkov Fedor I. , Zaytsev Vladimir P. , Voskressensky Leonid G. , Varlamov Alexey V. , de Candia Modesto , Fiorella Filomena , Altomare Cosimo 
Published: April 2012

AbstractA number of C‐3 spirocyclic 2‐benzazepine analogs of α‐phenyl‐N‐tert‐butyl nitrone (PBN) were synthesized and tested for their activity in protecting rat brain mitochondria and dopaminergic (DA) neurons against 6‐hydroxydopamine (6‐OHDA), a toxin inducing destruction of the DA nigro‐striatal pathway in rodent models of Parkinson's disease. The newly synthesized nitrone derivatives were firstly investigated for their activity in decreasing the level of hydroxyl radicals generated during 6‐OHDA oxidation, and inhibit lipid peroxidation (TBARS assay) and protein carbonyl content (PCC) in rat brain mitochondria. Most of the studied 2‐benzazepine nitrones showed inhibitory potencies in both TBARS and PCC assays at least two magnitude orders higher than that of PBN. The data obtained usefully complemented the known structure–activity relationships. In particular, 5 and 10, bearing C‐3 spiro cyclopentyl and tetrahydropyranyl moieties, respectively, at 8 µM concentration proved to be significantly more effective than PBN in protecting cultured DA neurons exposed to 6‐OHDA, which alone causes about 45% cell loss in 24 h. In addition, we found that 5 inhibited butyrylcholinesterase with an IC50 value of 16.8 µM, which would enhance its potential as neuroprotective agent in Alzheimer's neurodegeneration. These findings extend the utility of benzazepine‐based PBN analogs in the treatment of age‐related free radical‐mediated disorders.
Theoretical Study of Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Amino Acid‐Derived Rhodium Complexes
Authors: Nordin Mikael , Liao Rong‐Zhen , Ahlford Katrin , Adolfsson Hans , Himo Fahmi 
Published: April 2012

AbstractDensity functional theory calculations are employed to study the asymmetric transfer hydrogenation of ketones catalyzed by rhodium–arene complexes containing hydroxamic acid‐functionalized amino acid ligands. Firstly, the ligand–metal binding is investigated and it is shown that both the N,N and O,O binding modes Are viable. For each of these, the full free energy profile for the transfer hydrogenation is calculated according to the outer‐sphere reaction mechanism. Three factors are demonstrated to influence the stereoselectivity of the process, namely the energy difference between the metal–ligand binding modes, the energy difference between the intermediate hydrogenated catalyst, and the existence of a stabilizing CH–π interaction between the Cp* ligand of the catalyst and the phenyl moiety of the substrate. Theoretical reproduction of the selectivity of a slightly modified ligand that is shown experimentally to yield the opposite enantioselectivity corroborates these results. Finally, a technical observation made is that inclusion of dispersion interactions (using the B3LYP‐D2 correction or the M06 functional) proved to be very important for reproducing the enantioselectivity.
Site‐Selected Doping of Upconversion Luminescent Er3+ into SrTiO3 for Visible‐Light‐Driven Photocatalytic H2 or O2 Evolution
Authors: Shi Jinwen , Ye Jinhua , Ma Lijing , Ouyang Shuxin , Jing Dengwei , Guo Liejin 
Published: April 2012

AbstractA series of upconversion luminescent erbium‐doped SrTiO3 (ABO3‐type) photocatalysts with different initial molar ratios of Sr/Ti have been prepared by a facile polymerized complex method. Er3+ ions, which were gradually transferred from the A to the B site with increasing Sr/Ti, enabled the absorption of visible light and the generation of high‐energy excited states populated by upconversion processes. The local internal fields arising from the dipole moments of the distorted BO6 octahedra promoted energy transfer from the high‐energy excited states of Er3+ with B‐site occupancy to the host SrTiO3 and thus enhanced the band‐to‐band transition of the host SrTiO3. Consequently, the erbium‐doped SrTiO3 species with B‐site occupancy showed higher photocatalytic activity than those with A‐site occupancy for visible‐light‐driven H2 or O2 evolution in the presence of the corresponding sacrificial reagents. The results generally suggest that the introduction of upconversion luminescent agents into host semiconductors is a promising approach to simultaneously harnessing low‐energy photons and maintaining redox ability for photocatalytic H2 and O2 evolution and that the site occupancy of doped elements in ABO3‐type perovskite oxides greatly determines the photocatalytic activity.
Axial Ligand and Spin‐State Influence on the Formation and Reactivity of Hydroperoxo–Iron(III) Porphyrin Complexes
Authors: Franke Alicja , Fertinger Christoph , van Eldik Rudi 
Published: April 2012

AbstractThe present study focuses on the formation and reactivity of hydroperoxo–iron(III) porphyrin complexes formed in the [FeIII(tpfpp)X]/H2O2/HOO− system (TPFPP=5,10,15,20‐tetrakis(pentafluorophenyl)‐21H,23H‐porphyrin; X=Cl− or CF3SO3−) in acetonitrile under basic conditions at −15 °C. Depending on the selected reaction conditions and the active form of the catalyst, the formation of high‐spin [FeIII(tpfpp)(OOH)] and low‐spin [FeIII(tpfpp)(OH)(OOH)] could be observed with the application of a low‐temperature rapid‐scan UV/Vis spectroscopic technique. Axial ligation and the spin state of the iron(III) center control the mode of OO bond cleavage in the corresponding hydroperoxo porphyrin species. A mechanistic changeover from homo‐ to heterolytic OO bond cleavage is observed for high‐ [FeIII(tpfpp)(OOH)] and low‐spin [FeIII(tpfpp)(OH)(OOH)] complexes, respectively. In contrast to other iron(III) hydroperoxo complexes with electron‐rich porphyrin ligands, electron‐deficient [FeIII(tpfpp)(OH)(OOH)] was stable under relatively mild conditions and could therefore be investigated directly in the oxygenation reactions of selected organic substrates. The very low reactivity of [FeIII(tpfpp)(OH)(OOH)] towards organic substrates implied that the ferric hydroperoxo intermediate must be a very sluggish oxidant compared with the iron(IV)–oxo porphyrin π‐cation radical intermediate in the catalytic oxygenation reactions of cytochrome P450.
Silicon‐Containing Formal 4π‐Electron Four‐Membered Ring Systems: Antiaromatic, Aromatic, or Nonaromatic?
Authors: Yang Yun‐Fang , Cheng Gui‐Juan , Zhu Jun , Zhang Xinhao , Inoue Shigeyoshi , Wu Yun‐Dong 
Published: April 2012

AbstractDensity functional theory calculations (B3LYP) have been carried out to investigate the 4π‐electron systems of 2,4‐disila‐1,3‐diphosphacyclobutadiene (compound 1) and the tetrasilacyclobutadiene dication (compound 2). The calculated nucleus‐independent chemical shift (NICS) values for these two compounds are negative, which indicates that the core rings of compounds 1 and 2 have a certain amount of aromaticity. However, deep electronic analysis reveals that neither of these two formal 4π‐electron four‐membered ring systems is aromatic. Compound 1 has very weak, almost negligible antiaromaticity, and the amidinate ligands attached to the Si atoms play an important role in stabilizing this conjugated 4π‐electron system. The monoanionic bidentate ligand interacts with the conjugated π system to cause π‐orbital splitting. This ligand‐induced π‐orbital splitting effect provides an opportunity to manipulate the gap between occupied and unoccupied π orbitals in conjugated systems. Conversely, compound 2 is nonaromatic because its core ring does not have a conjugated π ring system and does not fulfill the requirements of a Hückel system.
Additional Base‐Pair Formation in DNA Duplexes by a Double‐Headed Nucleotide
Authors: Madsen Charlotte S. , Witzke Sarah , Kumar Pawan , Negi Kushuma , Sharma Pawan K. , Petersen Michael , Nielsen Poul 
Published: April 2012

AbstractWe have designed and synthesised a double‐headed nucleotide that presents two nucleobases in the interior of a dsDNA duplex. This nucleotide recognises and forms Watson–Crick base pairs with two complementary adenosines in a Watson–Crick framework. Furthermore, with judicious positioning in complementary strands, the nucleotide recognises itself through the formation of a T:T base pair. Thus, two novel nucleic acid motifs can be defined by using our double‐headed nucleotide. Both motifs were characterised by UV melting experiments, CD and NMR spectroscopy and molecular dynamics simulations. Both motifs leave the thermostability of the native dsDNA duplex largely unaltered. Molecular dynamics calculations showed that the double‐headed nucleotides are accommodated in the dsDNA by entirely local perturbations and that the modified duplexes retain an overall B‐type geometry with the dsDNA unwound by around 25 or 60°, respectively, in each of the modified motifs. Both motifs can be accommodated twice in a dsDNA duplex without incurring any loss of stability and extrapolating from this observation and the results of modelling, it is conceivable that both can be multiplied several times within a dsDNA duplex. These new motifs extend the DNA recognition repertoire and may form the basis for a complete series of double‐headed nucleotides based on all 16 base combinations of the four natural nucleobases. In addition, both motifs can be used in the design of nanoscale DNA structures in which a specific duplex twist is required.