bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tubulin Folding and Degradation
Authors: Serna Marina , Zabala Juan C 
Published: April 2016

Abstract

Synthesis of polypeptides inside a cell is an astonishing, complex and very efficient process. To reach the active state, proteins will have to face many different problems that in part are solved by molecular chaperones. Tubulins belong to one of the largest superfamilies of proteins with six conserved members. Different members have different roles although they share a general fold. Tubulins reach their final structure in an intricate pathway where different molecular chaperones are involved. Prefoldin and cytosolic chaperonin containing TCP1/TriC are required in the first part of the pathway, while tubulin folding cofactors (TBCs) are involved in the formation of the α‐ and β‐tubulin heterodimers. Later, their role in tubulin proteostasis as well as their implications in different neurodevelopmental disorders has been documented.

Key Concepts

Tubulins represent one of the largest families of genes and proteins.

α‐ and β‐Tubulin heterodimers constitute the structural and functional subunit of microtubules (MTs).

Folding of tubulins follows a sophisticated pathway involving several molecular chaperones.

Formation of the αβ‐tubulin heterodimer is an extremely regulated process for it is involved in different lateral and longitudinal as well as microtubule associated proteins (MAPs) interactions.

TBCs are molecular chaperones specifically required for αβ‐tubulin dimer formation.

TBCs are shown to be involved in the release of tubulin monomers from the chaperonin during the folding pathway.

The dissociation constant for the tubulin heterodimer has shown to be 10
−11
M and TBCs are required for an efficient tubulin dimer dissociation.

TBCs are involved in tubulin proteostasis through dimer dissociation and tagging for proteasome recognition.

The first 3D structure of a complex formed between α‐tubulin and two chaperones involved in the tubulin turnover cycle has been established.

Genetic defects on TBCs are responsible of neurodevelopmental diseases.
Palladium‐Catalyzed Tandem Reaction of Alkyne‐Based Aryl Iodides and Salicyl N‐Tosylhydrazones to Construct the Spiro[benzofuran‐3,2′‐chromene] Skeleton
Authors: Shang Xue Song , Li Nian Tai , Li Deng Yuan , Liu Pei Nian 
Published: April 2016

AbstractA convenient palladium‐catalyzed tandem reaction of aryl iodides and salicyl N‐tosylhydrazones has been achieved to afford a series of compounds containing the novel spiro[benzofuran‐3,2′‐chromene] scaffold in moderate to good yields. This efficient catalytic reaction, which tolerates various functional groups, combines alkyne‐based 5‐exo‐dig cyclization, palladium(II) carbene migratory insertion and intramolecular cyclization, generating three new bonds in one reaction.magnified image
Synthesis of 2‐Aryl‐Substituted Indole‐3‐acetic Acid Derivatives via Intramolecular Imino‐Stetter Reaction of Aldimines with Cyanide
Authors: Lee Seong Jong , Seo Hong‐Ahn , Cheon Cheol‐Hong 
Published: April 2016

AbstractA general method to generate umpolung of aldimines with cyanide was developed via the addition of cyanide to aldimines followed by a proton transfer from the carbon atom to the nitrogen atom in the resulting cyanide adducts. This novel method was successfully applied to the first imino‐Stetter reaction of aldimines obtained from 2‐aminocinnamic acid derivatives and aromatic aldehydes with cyanide, affording 2‐aryl‐substituted indole‐3‐acetic acid derivatives. Furthermore, the usefulness of this method was successfully demonstrated by the synthesis of an FPTase inhibitor, one of the biologically important 2‐arylindole‐3‐acetic acid derivatives.magnified image
A First Example of Cobalt‐Catalyzed Remote CH Functionalization of 8‐Aminoquinolines Operating through a Single Electron Transfer Mechanism
Authors: Whiteoak Christopher J. , Planas Oriol , Company Anna , Ribas Xavi 
Published: April 2016

AbstractThe development of new CH functionalization protocols based on inexpensive cobalt catalysts is currently attracting significant interest. Functionalized 8‐aminoquinoline compounds are high‐potential building blocks in organic chemistry and pharmaceutical compounds and new facile routes for their preparation would be highly valuable. Recently, copper has been applied as catalyst for the functionalization of 8‐aminoquinoline compounds and found to operate through a single electron transfer (SET) mechanism, although requiring elevated reaction temperatures. Herein, we described the first example of a cobalt‐catalyzed remote CH functionalization of 8‐aminoquinoline compounds operating through a SET mechanism, exemplified using a practical and mild nitration protocol. The reaction uses inexpensive cobalt nitrate hexahydrate [Co(NO3)2⋅6 H2O] as catalyst and tert‐butyl nitrite (TBN) as nitro source. This methodology offers the basis for the facile preparation of many new functionalized 8‐aminoquinoline derivatives.magnified image
Association of intracellular Staphylococcus aureus with prognosis in chronic rhinosinusitis
Authors: Ou Judy , Drilling Amanda , Singhal Deepti , Tan Neil C.‐W. , Wallis‐Hill Deanna , Vreugde Sarah , Psaltis Alkis J. , Wormald Peter‐John 
Published: April 2016

BackgroundStaphylococcus aureus (S. aureus) has been shown to exist within nasal epithelial cells in chronic rhinosinusitis (CRS) patients. This study investigates the localization of intracellular S. aureus (ICSA) in CRS patients, the associated histopathology changes, and their effect on long‐term postoperative outcomes.MethodsA prospective study of patients with CRS with and without polyps and control patients (n = 25, 15, and 8, respectively) undergoing endoscopic sinus surgery was performed. Validated patient reported symptom scores and objective endoscopic scores were collected preoperatively and 12 months postoperatively. Mucosal tissue samples were collected and examined for the presence of ICSA using immunohistochemical analysis. Tissue also underwent routine hematoxylin and eosin and Sirius Red staining to evaluate the inflammatory cell load and extent of fibrosis.ResultsICSA appeared to localize to the perinuclear region of the pseudostratified columnar respiratory epithelium. ICSA was more prevalent in CRS without nasal polyps (CRSsNP) than in CRS with nasal polyps (CRSwNP) or controls (80% vs 56% vs 38%, respectively). ICSA positive status did not appear to influence symptom or endoscopic scores at the time of surgery nor 12 months postoperatively. Lymphocytes and total inflammatory cells were significantly increased in ICSA+ group than ICSA− groups (36.4 vs 22.4 cells/area and 53.8 vs 29.1 cells/area, respectively). There was no difference found in fibrosis.ConclusionThis study indicated that ICSA was most prevalent in CRSsNP patients and was associated with increased lymphocytia and total inflammatory cells but not with worse symptomatology, endoscopy results, or basement membrane (BM) thickening.
Effects of a honeybee lactic acid bacterial microbiome on human nasal symptoms, commensals, and biomarkers
Authors: Mårtensson Anders , Greiff Lennart , Lamei Sepideh S. , Lindstedt Malin , Olofsson Tobias C. , Vasquez Alejandra , Cervin Anders 
Published: April 2016

BackgroundLactic acid bacteria (LAB) can restore commensal microbiomes and prevent infections. Arguably, nasal administrations of LAB may therefore be beneficial in chronic rhinosinusitis (CRS). Previous studies have examined effects of topical/nasal LAB in children with secretory otitis media, but little is as yet known about their effects on the human nasal airway. The aim of this pilot study was to examine effects on nasal symptoms and commensal bacteria in healthy subjects of nasal administration of a honeybee LAB microbiome; ie, a mixture of 9 Lactobacillus spp. and 4 Bifidobacterium spp. obtained from the honeybee Apis mellifera. Furthermore, we aimed to assess whether or not the honeybee LAB produced a local inflammatory response.MethodsTwenty‐two healthy subjects received a single administration of honeybee LAB in a sham‐controlled, double‐blinded, and crossover design. Using questionnaires, microbiological methods, and nasal lavages, they were assessed regarding symptoms, changes to commensal bacteria, and inflammatory products in nasal lavage fluids.ResultsThe honeybee LAB did not produce any symptoms or other untoward effects. No changes were observed of commensal bacteria by the honeybee LAB, and no inflammatory response was detected (compared to sham); ie, unaffected nasal lavage fluid levels of monocyte chemoattractant protein‐1 (MCP‐1), interleukin‐8 (IL‐8), monokine induced by interferon‐γ (MIG), interleukin‐15 (IL‐15), epidermal growth factor (EGF), eotaxin, interferon gamma‐induced protein‐10 (IP‐10), and interleukin‐1 receptor antagonist (IL‐1RA).ConclusionA single human nasal administration of a honeybee LAB microbiome is well tolerated. Specifically, it does not affect commensal bacteria and does not produce an inflammatory response.
Gender‐specific analysis of outcomes from endoscopic sinus surgery for chronic rhinosinusitis
Authors: Lal Devyani , Golisch Kimberly B. , Elwell Zachary A. , Divekar Rohit D. , Rank Matthew A. , Chang Yu‐Hui 
Published: April 2016

BackgroundWomen electing endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS) report higher symptom burden but have lower computed tomography (CT) scores. Gender‐specific analysis of outcomes from ESS therefore merits further study. The objective of this work was to study gender‐specific differences in outcomes from ESS for CRS by analyzing preoperative and postoperative 22‐item Sino‐Nasal Outcome Test (SNOT‐22) scores.MethodsData from adult CRS patients electing ESS (2011‐2013) were retrospectively collected. SNOT‐22 total, rhinologic/nonrhinologic subdomain, and individual item scores were analyzed for gender‐specific differences.ResultsTwo hundred and forty‐eight patients met study criteria (mean age 55.4 years; 49.6% female). Preoperatively, mean Lund‐Mackay CT score was 11.1; average total SNOT‐22 score was 41.9. Compared to men, women had lower CT score (10.2 vs 12.0; p = 0.004) but higher total SNOT‐22 score (44.7 vs 39.1; p = 0.02). Both genders showed significant improvement in total SNOT‐22 scores at 3, 6, 12, and 24 months following ESS (p < 0.001), with largely similar slopes of improvement. The greatest improvement occurred at 3 months (SNOT‐22 decreased by 25.4 points), with stable improvement after 12 months (SNOT‐22 decreased by 21.3 points). Higher total SNOT‐22 scores in females were noted preoperatively and until 6 months post‐ESS; these were driven by rhinologic and nonrhinologic‐otolaryngic subdomain items. No gender differences in anxiety/depression prevalence or psychological subdomain scores were noted preoperatively or postoperatively.ConclusionBoth male and female CRS patients showed significant and durable symptom relief following ESS. Women reported higher symptom burden prior to surgery, and in the early postoperative period. However, after 1‐year post‐ESS, both genders showed similar symptom scores. The trend and magnitude of improvement were similar in both genders.
Reductive Cross‐Coupling of Conjugated Arylalkenes and Aryl Bromides with Hydrosilanes by Cooperative Palladium/Copper Catalysis
Authors: Semba Kazuhiko , Ariyama Kenta , Zheng Hong , Kameyama Ryohei , Sakaki Shigeyoshi , Nakao Yoshiaki 
Published: April 2016

AbstractA method for the reductive cross‐coupling of conjugated arylalkenes and aryl bromides with hydrosilanes by cooperative palladium/copper catalysis was developed, thus resulting in the highly regioselective formation of various 1,1‐diarylalkanes, including a biologically active molecule. Under the applied reaction conditions, high levels of functional‐group tolerance were observed, and the reductive cross‐coupling of internal alkynes with aryl bromides afforded trisubstituted alkenes.
Ultrafine Metal–Organic Right Square Prism Shaped Nanowires
Authors: Otake Ken‐ichi , Otsubo Kazuya , Sugimoto Kunihisa , Fujiwara Akihiko , Kitagawa Hiroshi 
Published: April 2016

AbstractWe report the structural design and control of electronic states of a new series of ultrafine metal–organic right square prism‐shaped nanowires. These nanowires have a very small inner diameter of about 2.0 Å, which is larger than hydrogen and similar to xenon atomic diameters. The electronic states of nanowires can be widely controlled by substitution of structural components. Moreover, the platinum homometallic nanowire shows a 100 times higher proton conductivity than a palladium/platinum heterometallic one depending on the electronic states.
Phosphine‐mediated Highly Enantioselective Spirocyclization with Ketimines as Substrates
Authors: Han Xiaoyu , Chan Wai‐Lun , Yao Weijun , Wang Yongjiang , Lu Yixin 
Published: April 2016

AbstractPhosphine‐catalyzed enantioselective annulation reactions involving ketimines are a daunting synthetic challenge owing to the intrinsic low reactivity of ketimine substrates. A highly enantioselective [3+2] cycloaddition reaction that makes use of isatin‐derived ketimines as reaction partners was developed. Notably, both simple and γ‐substituted allenoates could be utilized, and various 3,2′‐pyrrolidinyl spirooxindoles with a tetrasubstituted stereocenter were obtained in excellent yields and with nearly perfect enantioselectivity (>98 % ee in all cases).
Magnetically and Near‐Infrared Light‐Powered Supramolecular Nanotransporters for the Remote Control of Enzymatic Reactions
Authors: Chechetka Svetlana A. , Yuba Eiji , Kono Kenji , Yudasaka Masako , Bianco Alberto , Miyako Eijiro 
Published: April 2016

AbstractCancer is one of the primary causes of death worldwide. A high‐precision analysis of biomolecular behaviors in cancer cells at the single‐cell level and more effective cancer therapies are urgently required. Here, we describe the development of a magnetically‐ and near infrared light‐triggered optical control method, based on nanorobotics, for the analyses of cellular functions. A new type of nanotransporters, composed of magnetic iron nanoparticles, carbon nanohorns, and liposomes, was synthesized for the spatiotemporal control of cellular functions in cells and mice. Our technology will help to create a new state‐of‐the‐art tool for the comprehensive analysis of “real” biological molecular information at the single‐cell level, and it may also help in the development of innovative cancer therapies.
Investigation on the effect of spinning conditions on the properties of hollow fiber membrane for hemodialysis application
Authors: Mansur Sumarni , Othman Mohd Hafiz Dzarfan , Ismail A. F. , Sheikh Abdul Kadir Siti Hamimah , Kamal Fatmawati , Goh Pei Sean , Hasbullah Hasrinah , Ng Bee Cheer , Abdullah Mohd Sohaimi 
Published: April 2016

ABSTRACTPolyethersulfone (PES) hollow fiber membranes were fabricated via the dry‐wet phase inversion spinning technique, aiming to produce an asymmetric, micro porous ultrafiltration hollow‐fiber specifically for hemodialysis membrane. The objective of this study is to investigate the effect of spinning conditions on the morphological and permeation properties of the fabricated membrane. Among the parameters that were studied in this work are air gap distance, dope extrusion rate, bore fluid flow rate, and the take‐up speed. The contact angle was measured to determine the hydrophilicity of the fibers. Membrane with sufficient hydrophilicity properties is desired for hemodialysis application to avoid fouling and increase its biocompatibility. The influences of the hollow fiber's morphology (i.e., diameter and wall thickness) on the performance of the membranes were evaluated by pure water flux and BSA rejection. The experimental results showed that the dope extrusion rate to bore fluid flow rate ratio should be maintained at 1:1 ratio to produce a perfectly rounded asymmetric hollow fiber membrane. Moreover, the flux of the hollow fiber spun at higher air gap distance had better flux than the one spun at lower air gap distance. Furthermore, spinning asymmetric hollow fiber membranes at high air gap distance helps to produce a thin and porous skin layer, leading to a better flux but a relatively low percentage of rejection for BSA separation. Findings from this study would serve as primary data which will be a useful guide for fabricating a high performance hemodialysis hollow fiber membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43633.
High‐efficiency recovery of rare earth ions by hydrolyzed poly(styrene‐co‐maleic anhydride)
Authors: Gui Wenjun , Yang Ying , Zhu Xuan 
Published: April 2016

ABSTRACTHydrolyzed poly(styrene‐co‐maleic anhydride) (PSMA) as a high‐efficiency adsorbent is used for recovering La3+, Eu3+, Tb3+, and Yb3+ from the simulate wastewater of bastnaesite leach liquor. The pseudo‐first‐order and pseudo‐second‐order models are used to fit adsorption data in the kinetic studies and the results show good correlation with the pseudo‐second‐order model. The Langmuir model is found to fit for the isotherm data of all the rare earth ions (RE3+) and the maximum adsorption capacity of hydrolyzed PSMA is 285.79, 301.92, 305.46, and 336.65 mg g−1 at 298 K for La3+, Eu3+, Tb3+, and Yb3+, respectively. The adsorption could be conducted in at pH 6.0 and the equilibrium is fast established in 30 min. Competition from coexisting ions (Ca2+, Mg2+) was proved to be insignificant. Moreover, the spent adsorbent could be well regenerated and kept above 80% of adsorption efficiency at the end of the fifth cycle. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43676.
Quaternized poly(phenylene oxide) anion exchange membrane for alkaline direct methanol fuel cells in KOH‐free media
Authors: Gopi K. Hari , Bhat Santoshkumar D. , Sahu Akhila Kumar , Sridhar P. 
Published: April 2016

ABSTRACTA series of anion exchange membrane (AEM) electrolytes with quaternary ammonium moiety are fabricated from poly (phenylene oxide) for its application in alkaline direct methanol fuel cells (ADMFCs). In the first step, poly(phenylene oxide) (PPO) is successfully chloromethylated by substituting chloromethyl groups in the aryl position of polymer. In the second step, the chloromethylated PPO (CPPO) is further homogeneously quaternized and ion‐exchanged to form an AEM. From the second step, series of AEMs are prepared by changing the mole ratio of amine in relation to CPPO. The presence of quaternary ammonium group in the membrane was confirmed by elemental analysis. The fabricated membranes are subjected to cell polarization studies in ADMFCs, wherein quaternized poly(2,6‐dimethyl‐1,4‐phenylene oxide) (CPPO:amine of 1:8) membrane exhibits higher peak power density of 3.5 mW cm−2 when compared with the other ratios of CPPO:amine in the absence of KOH solution. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43693.
Synthesis and characterization of multi‐hollow opaque polymer pigments
Authors: Asmaoğlu Serdar , Gündüz Güngör , Maviş Bora , Çolak Üner 
Published: April 2016

ABSTRACTA new generation multihollow opaque polymer pigment was synthesized by suspension polymerization of “water‐in‐oil‐in‐water” emulsion method, where methyl methacrylate and ethylene glycol dimethacrylate monomer mixture was used as oil phase. The effects of surfactant and cosurfactant composition in terms of “hydrophilic/lipophilic balance” on the stability of the “water‐in‐oil” emulsion and the size of water droplets were studied. Low droplet sizes and the optimum stability were obtained with “Span 80&Tween 80” surfactant mixture at an HLB value of 8. The desired size distribution was obtained at “monomer/surfactant/water” ratio of 75.5/9.4/15.1 at an ultrasonic mixing power of 80 W lasting for 30 s. The surface morphology and hollow structure of polymer pigments were analyzed by scanning and transmission electron microscopy techniques. L*a*b color and gloss properties of polymer pigments were examined. The opacity values were assessed by contrast ratio measurements, and the pigments provided up to 97.3% opacity with 50% v/v solid content in resin. In addition, the pigments exhibited low gloss values and yielded matte films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43696.
Characteristics of wet‐spun and thermally treated poly acrylonitrile fibers
Authors: Kirsten Martin , Meinl Juliane , Schönfeld Katrin , Michaelis Alexander , Cherif Chokri 
Published: April 2016

ABSTRACTThe performance of carbon fibers depends on the quality of the precursor and the conditions of the thermal treatment. In detail, for a PAN precursor fiber the viscosity of a spinning dope and the draw ratio during the spinning process needs to be considered. Through wet spinning, different types of PAN precursor fibers with defined spinning parameters, including solid content, solvent content in a bath, and especially draw ratio resulting in defined cross section diameters, were fabricated and analyzed with tensile tests, density investigations, SEM, TGA‐MS, FTIR, and XRD. The results show that the mechanical properties of the fibers correlate to crystallinity. The cross section diameter is strongly related to the morphology of the fibers after thermal treatment. By extending the postdrawing of PAN fibers high tenacities were obtained at the cost of the cross section shape. In addition, TGA measurements reveal trapped residues of the wet spinning process as well as show several chemical reactions takes place at the same time at different temperatures. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43698.
Scrutinizing the influence of peroxide crosslinking of dynamically vulcanized EVA/TPU blends with special reference to cable sheathing applications
Authors: Dutta Joyeeta , Ramachandran Padmanabhan , Naskar Kinsuk 
Published: April 2016

ABSTRACTA novel thermoplastic vulcanizate (TPV) based on the blends of ethylene vinyl acetate/thermoplastic polyurethane (EVA/TPU) at various blend ratios has been developed via dynamic vulcanization at 180 °C using di‐(2‐tert‐butyl peroxy isopropyl) benzene (DTBPIB) peroxide as the cross‐linking agent. Modification of the EVA/TPU blends via dynamic crosslinking significantly improves the tensile strength and modulus of the system and the improvement is more significant for EVA/TPU 50/50 and 60/40 blends. AFM study shows that crosslinked EVA particles are dispersed in the continuous TPU matrix and the dispersed EVA domain sizes are relatively smaller in EVA/TPU 50/50 and 60/40 blends leading to good mechanical properties. FTIR spectroscopy has been used to characterize the specific chemical changes occurring due to dynamic vulcanization. This TPV has excellent retention of physico‐mechanical properties even after reprocessing twice and the blends also have very good thermal resistance as indicated by aging study. The samples were found to exhibit remarkable improvement in oil resistance property as compared to their uncrosslinked counterpart. The creep behavior of the blends significantly improves after dynamic crosslinking and blends with higher TPU content show better creep resistance. Volume resistivity of all the peroxide vulcanized blends is in the range of 1013ohm cm, which is suitable for cable sheathing application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2016,133, 43706.