bluuebunny/crossref_metadata_2025_split huggingface dataset:
The imprinting induce‐fit model of specific rebinding of macromolecularly imprinted polymer microspheres
Authors: Ying Xiaoguang , Cheng Guoxiang , Li Xiao 
Published: June 2011

AbstractThe rebinding behavior of protein‐imprinted hydrogel is different from classical small molecularly imprinted polymer especially in protein aggregating state and interaction changeability between protein and imprinted sites. BSA‐imprinted calcium alginate‐hydroxy ethyl cellulose microspheres were prepared, and the rebinding behavior was studied. An “imprinting induce‐fit model” was proposed to describe the rebinding property of protein‐imprinted hydrogel. Three kinds of different interacting forms between protein and imprinted hydrogel were discovered by Scatchard analysis. Slogistic fit analysis of rebinding rate coefficient was carried out, and the imprinted hydrogel was found capable of promoting rebinding through induce‐fit behavior. Higher imprinting efficiency was found in microsphere samples with lower crosslinking density. Rebinding regression equation was established, and the rebinding quantity was computable with parameters including BSA aggregate concentration [Pn], dissociating rate (k1), and single molecule rebinding rate (k2). The experimental and calculated rebinding concentration were compared, and errors between −9.43% and 5.59% were found. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122:1847–1856, 2011
Epoxy resin modified with in situ generated metal oxides by means of sol–gel process
Authors: Bondioli Federica , Darecchio Maria Elena , Luyt Adrian S. , Messori Massimo 
Published: June 2011

AbstractOrganic–inorganic hybrids were prepared with silica, zirconia, or titania in situ generated within epoxy resins based on bisphenol A diglycidyl ether and Jeffamine® by means of the aqueous sol–gel process. The morphology of the prepared hybrids varied from a particulate dispersed phase to a co‐continuous morphology. Silica and zirconia filled epoxies were characterized by a significant increase in thermal stability, attributable to the high thermal stability of silica and zirconia phases. On the contrary, the introduction of titania induced a strong decrease in thermal stability of the epoxy/titania hybrids compared with the pure epoxy resin, attributable to metal‐catalyzed oxidative decomposition mechanism in the polymer/titania composite. Hybrids were much more transparent than unfilled epoxy. The transmittance of silica‐ and titania‐based hybrids showed a slight decrease by increasing the content of filler, while the transparency of zirconia‐based hybrids was very high and almost constant independently by the nominal content of filler. The presence of in situ generated fillers significantly enhanced the scratch resistance of the epoxy resin as indicated by the marked increase of critical load for all the hybrids. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermodynamical study of poly(n‐hexyl methacrylate) with some solvents by inverse gas chromatography
Authors: Yazici Ozlem , Sakar Dolunay , Cankurtaran Ozlem , Karaman Ferdane 
Published: June 2011

AbstractThe retention volume diagrams of ethyl acetate, isobutyl acetate, tert‐butyl acetate, benzene, n‐hexane, n‐heptane, n‐octane, acetone, chloroform, and acetonitrile on the poly(n‐hexyl methacrylate) (PHMA) were plotted at temperature ranges from 333 to 393 K by inverse gas chromatography technique. Some polymer‐solvent thermodynamic interaction parameters, such as weight fraction activity coefficient, Ω, Flory‐Huggins, χ, hard‐core, χ, and some exchange parameters such as effective energy, Xeff, enthalpy, X12, and entropy, Q12, were determined for studied solvents at infinite dilution of PHMA at temperatures mentioned above. Then the partial molar heat,
$\Delta \overline H_1^s$, and free energy,
$\Delta \overline G_1^s$, of sorption as well as the partial molar heat,
$\Delta \overline H_1^\infty$, and free energy,
$\Delta \overline G_1^\infty$, of mixing at infinite dilution were determined. In addition, the solubility parameter of PHMA, δ2, was determined as 8.8 (cal/cm3)1/2 at room temperature by extrapolation of the values of solubility parameters from studied temperatures to 298 K. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and thermal properties of multiwalled carbon nanotube/polybenzoxazine nanocomposites
Authors: Huang Jieh‐Ming , Tsai Ming‐Feng , Yang Shung‐Jim , Chiu Wei‐Ming 
Published: June 2011

AbstractIn this study, we prepared nanocomposites comprising multiwalled carbon nanotubes (MWCNTs) and polybenzoxazine (PBZ). The MWCNTs were purified through microwave digestion to remove most of the amorphous carbon and metal impurities. After purification, MWCNTs were treated with H2SO4/HNO3 (3 : 1) to introduce hydroxyl and carboxyl groups onto their surfaces. Raman spectroscopy revealed the percentage of nanotube content improved after prolonged microwave treatment, as evidenced by the decrease in the ratio of the D (1328 cm−1) and G (1583 cm−1) bands. For the untreated MWCNTs, the ID/IG ratio was 0.56. After microwave treatment for 40 min, the value decreased to 0.29, indicating that the percentage of nanotube content improved. Dynamic mechanical analyses (DMAs) revealed that the storage moduli and the Tgs of the MWCNTs/PBZ nanocomposites were higher than that of the pristine PBZ. This is due to the nanometer‐scale MWCNTs restricting the motion of the macromolecular chains in the nanocomposites. Transmission electron microscopy (TEM) image revealed that the MWCNTs were well dispersed within the PBZ matrix on the nanoscale when the MWCNT content was less than 2.0 phr. The coefficient of thermal expansion (CTE) of the nanocomposites decreased on increasing the MWCNTs content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Melt memory effects on recrystallization of polyamide 6 revealed by depolarized light scattering and small‐angle X‐ray scattering
Authors: Kawabata Jun , Matsuba Go , Nishida Koji , Inoue Rintaro , Kanaya Toshiji 
Published: June 2011

AbstractMelt memory effects on recrystallization of polyamide 6 were studied in a length scale from nm to μm using small‐angle X‐ray scattering (SAXS) and depolarized light scattering (DPLS). The memory effects on recrystallization rate were discussed in terms of the incubation period before nucleation and the half time of the crystallization, which were measures of the nucleation rate and the growth rate, respectively. Both rates are almost independent of the annealing temperature of the melt in the remelting process for the short term annealing below ∼ 3 min while they are slowed as the annealing temperature increases for the long term annealing, showing that the relaxation of melt memory takes very long even above the equilibrium melting temperature T. Extrapolating the incubation period to infinite annealing, time we found that it was very hard to attain the fully relaxed state in polyamide 6 even above the equilibrium melting temperature. This must be due to the strong hydrogen bonding in polyamide 6. We also discuss the memory effects on the final structure after recrystallization based on the SAXS and DPLS profiles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Amplitude–frequency characteristics of polymer electro‐magnetic dynamic tri‐screw extrusion
Authors: Guangsheng Zeng , Taijun Jiang , Jinping Qu , Yuejun Liu 
Published: June 2011

AbstractThe mechanism of plastic forming and processing in electromagnetic dynamic tri‐screw extruder is very sophisticated and the investigation of amplitude–frequency characteristic acts as the foundation of equipment design and the optimization of polymer processing parameters. A mathematical and analytical model of plastic forming in such extruder was developed and the results were nondimensional‐normalized. To validate the mathematical solutions experiments based on LDPE were carried out and the experimental vibration amplitude and vibration frequency curve was obtained. Three conclusions can be drawn herein: (1) the experimental results hold a good agreement with the calculations, and thus the feasibility of the proposed model is validated; (2) the possibility of resonance closely relates to polymer melt viscosity, rotating speed, and geometry parameters of the screw; (3) resonance of the tri‐screw extruder is seldom observed under normal conditions and there exists an inverse correlationship between vibration frequency and amplitude. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122:1778–1784, 2011
From biofuel to bioproduct: is bioethanol a suitable fermentation feedstock for synthesis of bulk chemicals?
Authors: Weusthuis Ruud A. , Aarts Jac M.M.J.G. , Sanders Johan P.M. 
Published: June 2011

AbstractThe first pilot‐scale factories for the production of bioethanol from lignocellulose have been installed, indicating that we are on the brink of overcoming most hurdles for an economically feasible process. When bioethanol is competitive as biofuel with fuels originating from petrochemical resources, it will also become interesting to use lignocellulose as a feedstock for the fermentative synthesis of bulk chemicals. Lignocellulose hydrolysates, however, are highly complex and viscous media, posing challenges to oxygen transfer, product formation at low sugar concentration, product recovery, etc. Bioethanol is an exceptional product in this respect because it can be produced anaerobically, at low sugar concentrations, and can be easily removed from the broth by distillation. For products that do not have these benefits, another approach may be interesting, in which lignocellulose is first converted to bioethanol, which in turn serves as a substrate for a second conversion into the desired product, similar to the traditional production of acetic acid in vinegar. In this perspective, we compare these one‐stage and two‐stage conversions with respect to overall yield and productivity of the fermentation process and the differences that occur in product removal. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
Presentation of the microscopic vascular architecture of the radial head using a sequential plastination technique
Authors: Koslowsky T.C. , Schliwa S. , Koebke J. 
Published: June 2011

AbstractThe purpose of this study was to demonstrate the peri‐ and intraosseous vascular architecture of the radial head and vascular interaction with surgical implants. Seventeen fresh human cadaveric elbows were sequentially plastinated beginning with arterial injection, followed by block and slice plastination of the whole elbow. With this technique, we obtained completely transparent cadaveric slices in which the peri‐ and intraosseous vascular architecture could be studied in its neutral position. In six of these elbows, radial head osteosynthesis was imitated with miniplates or fine threaded K‐wires. Vascularization of the radial head occurred via branches of the radial recurrent artery on the ventral, lateral, and dorsal sides of the radial head and a branch of the ulnar artery—ramus periostalis ulnaris—medially and dorsomedially. Both arteries create a pericervical arterial ring around the radial neck. A branch of the interosseous artery—R. interosseous recurrence—supports the ventral and dorsal sides of the radial neck and the final branches of the nutrient artery support intraosseous vascularization. Vascular structures were damaged more severely by plates than by screws. The peri‐ and intraosseous vascularization of the radial head and the interaction between vascularization and the implants was shown. Plate fixation of radial head fractures leads to a higher level of implant‐related destruction of the periosseous vascularization than screw fixation. Besides devascularization of the radial head due to the injury leading to a certain risk of fracture nonunion, additional implant‐related injuries to the blood supply might increase the chance of radial head fracture non‐union. Clin. Anat. 24:721–732, 2011. © 2011 Wiley‐Liss, Inc.
Anatomical variations of the lateral nasal wall: The secondary and accessory middle turbinates
Authors: El‐Shazly A.E. , Poirrier Anne‐Lise , Cabay J. , Lefebvre P.P. 
Published: June 2011

AbstractThe aim of the current anatomical and clinical study was to audit our cases of patients who presented with secondary and/or accessory middle turbinates during a two‐year period. We investigated the incidence and the clinical impact of these variations. Twenty‐eight patients, 19 males and 9 females with a mean age of 41.5 years, representing different ethnic origins, were diagnosed with double middle turbinates based on endoscopic examination. Of those, 92.8% had a main symptom of refractory frontal headache. A secondary nasal symptom was sensation of blocked nose. Patients who underwent endoscopic surgery (n = 13) for reduction of the extra turbinate, reported significant symptom scores improvement (P < 0.0001) of frontal headache and blocked nose, from means of 9.07 ± 0.26 and 8.57 ± 1.39 to 1 ± 0.31, and 1.42 ± 0.35, respectively. Our results indicate that double middle turbinates may be encountered in rhinology practice (2%). Clinically they may present with refractory headache and blocked nose. Endoscopic surgical approach seems to be an effective way of improving the symptoms. Clin. Anat. 25:340–346, 2012. © 2011 Wiley Periodicals, Inc.
Triptolide Directly Inhibits dCTP Pyrophosphatase
Authors: Corson Timothy W. , Cavga Hüseyin , Aberle Nicholas , Crews Craig M. 
Published: June 2011

AbstractTriptolide is a potent natural product, with documented antiproliferative, immunosuppressive, anti‐inflammatory, antifertility, and antipolycystic kidney disease effects. Despite a wealth of knowledge about the biology of this compound, direct intracellular target proteins have remained elusive. We synthesized a biotinylated photoaffinity derivative of triptolide, and used it to identify dCTP pyrophosphatase 1 (DCTPP1) as a triptolide‐interacting protein. Free triptolide interacts directly with recombinant DCTPP1, and inhibits the enzymatic activity of this protein. Triptolide is thus the first dCTP pyrophosphatase inhibitor identified, and DCTPP1 is a biophysically validated target of triptolide.
Revisiting the Mechanism of the Triosephosphate Isomerase Reaction: The Role of the Fully Conserved Glutamic Acid 97 Residue
Authors: Samanta Moumita , Murthy M. R. N. , Balaram Hemalatha , Balaram Padmanabhan 
Published: June 2011

AbstractAn analysis of 503 available triosephosphate isomerase sequences revealed nine fully conserved residues. Of these, four residues—K12, H95, E97 and E165—are capable of proton transfer and are all arrayed around the dihydroxyacetone phosphate substrate in the three‐dimensional structure. Specific roles have been assigned to the residues K12, H95 and E165, but the nature of the involvement of E97 has not been established. Kinetic and structural characterization is reported for the E97Q and E97D mutants of Plasmodium falciparum triosephosphate isomerase (Pf TIM). A 4000‐fold reduction in kcat is observed for E97Q, whereas the E97D mutant shows a 100‐fold reduction. The control mutant, E165A, which lacks the key catalytic base, shows an approximately 9000‐fold drop in activity. The integrity of the overall fold and stability of the dimeric structure have been demonstrated by biophysical studies. Crystal structures of E97Q and E97D mutants have been determined at 2.0 Å resolution. In the case of the isosteric replacement of glutamic acid by glutamine in the E97Q mutant a large conformational change for the critical K12 side chain is observed, corresponding to a trans‐to‐gauche transition about the CγCδ (χ3) bond. In the E97D mutant, the K12 side chain maintains the wild‐type orientation, but the hydrogen bond between K12 and D97 is lost. The results are interpreted as a direct role for E97 in the catalytic proton transfer cycle. The proposed mechanism eliminates the need to invoke the formation of the energetically unfavourable imidazolate anion at H95, a key feature of the classical mechanism.
AuaA, a Membrane‐Bound Farnesyltransferase from Stigmatella aurantiaca, Catalyzes the Prenylation of 2‐Methyl‐4‐hydroxyquinoline in the Biosynthesis of Aurachins
Authors: Stec Edyta , Pistorius Dominik , Müller Rolf , Li Shu‐Ming 
Published: June 2011

AbstractAurachins are quinoline alkaloids isolated from the myxobacterium Stigmatella aurantiaca. They are substituted with an isoprenoid side chain and act as potent inhibitors in the electron transport chain. A biosynthetic gene cluster that contains at least five genes (auaA–auaE) has been identified for aurachin biosynthesis. In this study, auaA, the gene encoding a putative prenyltransferase of 326 amino acids, was cloned and overexpressed in Escherichia coli. Biochemical investigations showed that AuaA catalyzes the prenylation of 2‐methyl‐4‐hydroxyquinoline in the presence of farnesyl diphosphate (FPP), thereby resulting in the formation of aurachin D. The hydroxyl group at position C4 of the quinoline ring is essential for an acceptance by AuaA; this was concluded by testing 18 quinoline derivatives or analogues with AuaA and FPP. 1H NMR and HR‐EI‐MS analyses of six isolated enzyme products revealed the presence of a farnesyl moiety at position C3 of the quinoline ring. KM values of 43 and 270 μM were determined for FPP and 2‐methyl‐4‐hydroxyquinoline, respectively. Like other known membrane‐bound prenyltransferases, the reaction catalyzed by AuaA is dependent on the presence of metal ions such as Mg2+, Mn2+ and Co2+, although no typical (N/D)DXXD binding motif was found in the sequence.
Peripheral Substitution of a Near‐IR‐Absorbing Soluble Phthalocyanine Using “Click” Chemistry
Authors: Mayukh Mayank , Lu Chin‐Wei , Hernandez Edgardo , McGrath Dominic V. 
Published: June 2011

AbstractA series of near‐IR‐absorbing soluble phthalocyanines (Pcs) with eight alkyne moieties as side chains of the chromophore have been synthesized. One of these Pcs has been used as a scaffold for functional group modification using alkyne–azide click chemistry with various azides. This led to a small library of Pcs with photo and thermal crosslinkable, dendritic, and hydrophilic moieties starting from a single Pc molecule. A patterned thin film was fabricated by photocrosslinking one of these Pc derivatives.
Total Synthesis of (+)‐(2′S,3′R)‐Zoapatanol Exploiting the B‐Alkyl Suzuki Reaction and the Nucleophilic Potential of the Sulfinyl Group
Authors: Raghavan Sadagopan , Sudheer Babu Vaddela 
Published: June 2011

AbstractA stereoselective synthesis of the diterpenoid oxepane (+)‐zoapatanol is described. The key steps include a B‐alkyl Suzuki cross‐coupling reaction for the stereoselective synthesis of trisubstituted alkenes, creation of the two stereogenic centers on the oxepane ring by heterofunctionalization of an alkene through substrate control exploiting the nucleophilic potential of an intramolecular sulfinyl group, and transformation of a β‐hydroxy sulfoxide into a terminal alkene.
MRI‐Guided Neutron Capture Therapy by Use of a Dual Gadolinium/Boron Agent Targeted at Tumour Cells through Upregulated Low‐Density Lipoprotein Transporters
Authors: Geninatti‐Crich Simonetta , Alberti Diego , Szabo Ibolya , Deagostino Annamaria , Toppino Antonio , Barge Alessandro , Ballarini Francesca , Bortolussi Silva , Bruschi Piero , Protti Nicoletta , Stella Sabrina , Altieri Saverio , Venturello Paolo , Aime Silvio 
Published: June 2011

AbstractThe upregulation of low‐density lipoprotein (LDL) transporters in tumour cells has been exploited to deliver a sufficient amount of gadolinium/boron/ligand (Gd/B/L) probes for neutron capture therapy, a binary chemio‐radiotherapy for cancer treatment. The Gd/B/L probe consists of a carborane unit (ten B atoms) bearing an aliphatic chain on one side (to bind LDL particles), and a GdIII/1,4,7,10‐tetraazacyclododecane monoamide complex on the other (for detection by magnetic resonance imaging (MRI)). Up to 190 Gd/B/L probes were loaded per LDL particle. The uptake from tumour cells was initially assessed on cell cultures of human hepatoma (HepG2), murine melanoma (B16), and human glioblastoma (U87). The MRI assessment of the amount of Gd/B/L taken up by tumour cells was validated by inductively coupled plasma‐mass‐spectrometric measurements of the Gd and B content. Measurements were undertaken in vivo on mice bearing tumours in which B16 tumour cells were inoculated at the base of the neck. From the acquisition of magnetic resonance images, it was established that after 4–6 hours from the administration of the Gd/B/L–LDL particles (0.1 and 1 mmol kg−1 of Gd and 10B, respectively) the amount of boron taken up in the tumour region is above the threshold required for successful NCT treatment. After neutron irradiation, tumour growth was followed for 20 days by MRI. The group of treated mice showed markedly lower tumour growth with respect to the control group.
Microenvironment Engineering in ortho‐ and para‐Dendronized Metalloporphyrin–Fullerene Conjugates Involving a trans‐2‐Bisaddition Pattern
Authors: Ruppert Michaela , Bauer Walter , Hirsch Andreas 
Published: June 2011

AbstractA new series of dendronized metalloporphyrin–fullerene conjugates as photosynthetic reaction center mimics was developed in a highly regioselective fashion through tether‐controlled synthesis. The microenvironment around the porphyrin core is dependent on the spatial substitution pattern and the nature and generation number of the dendrons, which was proven by cyclic voltammetry.
Stereoselective Hydrosilylation of Enals and Enones Catalysed by Palladium Nanoparticles
Authors: Benohoud Meryem , Tuokko Sakari , Pihko Petri M. 
Published: June 2011

AbstractA highly versatile and efficient hydrosilylation method by palladium nanoparticle catalysis allows the direct and chemoselective synthesis of 1) enolsilanes of high isomeric purity, 2) saturated aldehydes or ketones, or 3) the corresponding saturated acetals from α,β‐unsaturated aldehydes or ketones. The choice of the product is determined by simply switching the solvent from THF to mixtures of THF/water or THF/alcohol.
ChemInform Abstract: Properties of the GdTX (T: Mn, Fe, Ni, Pd, X: Al, In) and GdFe6Al6 Intermetallics.
Authors: Oboz M. , Talik E. 
Published: June 2011

AbstractThe magnetic and magnetocaloric properties of the title compounds for possible applications in magnetic refrigeration are investigated by magnetization measurements in the temperature range 2—400 K at magnetic fields of 0—7 T.
ChemInform Abstract: Halide Coordination of Perhalocyclohexasilane Si6X12 (X: Cl or Br).
Authors: Dai Xuliang , Choi Seok‐Bong , Braun Christopher W. , Vaidya Pooja , Kilina Svetlana , Ugrinov Angel , Schulz Douglas L. , Boudjouk Philip 
Published: June 2011

AbstractSingle crystal XRD results are reported for (I) (monoclinic, space group C2/c), (IIc) (monoclinic, P21/n, Z = 4), and (IVb, c) (triclinic, P$\bar 1$, Z = 1).
ChemInform Abstract: A Novel Sandwich‐Type Polyoxometalate Compound with Visible‐Light Photocatalytic H2 Evolution Activity.
Authors: Zhang Zhenyu , Lin Qipu , Zheng Shou‐Tian , Bu Xianhui , Feng Pingyun 
Published: June 2011

AbstractLarge orange‐red crystals of K11H [Sn4(SiW9O34)2] ·25H2O are synthesized by slow evaporation of an aq.
ChemInform Abstract: Gold(I)‐Catalyzed Cycloisomerization of 1,6‐Diynes: Synthesis of 2,3‐Disubstituted 3‐Pyrroline Derivatives.
Authors: Zhang Di‐Han , Yao Liang‐Feng , Wei Yin , Shi Min 
Published: June 2011

AbstractThe pyrrolidine derivatives can be converted into the corresponding pyrrole as is shown for (III).
ChemInform Abstract: Enantio‐ and Regioselective Iridium‐Catalyzed Allylic Hydroxylation.
Authors: Gaertner Martin , Mader Steffen , Seehafer Kai , Helmchen Guenter 
Published: June 2011

AbstractBranched allylic alcohols are prepared highly selectively using potassium bicarbonate as nucleophile and novel air‐ and water‐stable Ir‐catalysts.