bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theory of Gold‐Mediated Reactions: From Single Metal Site to Cluster
Authors: CHEN HUI , GAO YI 
Published: December 2014

Abstract
In recent years, gold‐mediated reactions have attracted considerable interests and witnessed explosive developments. Along with this trend, corresponding theoretical modelings are playing increasingly important role in the mechanism study of gold‐mediated reactions. In this chapter, we briefly discuss some recent advances in understanding of gold‐mediated reactions from theoretical modeling. Relevant theoretical methods as well as some technical issues for computational treatment of heavy element gold are introduced. As a key point in many homogenous gold‐mediated reactions that involve single metal site, substrate‐gold interaction is examined from theoretical point of view. Then the mechanisms of some typical homogenous gold‐mediated reactions are discussed. Concerning gold‐mediated reactions involving more than single metal site, CO oxidation by gold nanoclusters is discussed, with focus on structures of gold clusters and influencing factors for catalytic activities towards CO oxidation.
Gold‐Promoted Sigmatropic Rearrangements
Authors: Henrion Guilhem , Gagosz Fabien 
Published: December 2014

Abstract
Gold catalysis is particularly efficient in mediating various kinds of sigmatropic rearrangements that either correspond to an overall transformation of a substrate or simply occur as an elementary step in a reaction sequence. Among the sigmatropic rearrangements that can be gold‐promoted, particular attention has been brought to the Cope and Claisen rearrangements, and to the rearrangement of propargylic esters, which have been the subject of numerous experimental and theoretical investigations. Compared to the thermally induced version of such rearrangements, the use of electrophilic gold species as catalysts allows significant reduction in the energy demand so that transformations can generally be performed at moderate temperature with a good control of the chemo‐ and/or stereoselectivities. This chapter gives an overview of the various synthetic methods based on the use of gold‐promoted sigmatropic rearrangements that have been reported so far.
Copper Peroxide Bioinorganic Chemistry: From Metalloenzymes to Bioinspired Synthetic Systems
Authors: Garcia‐Bosch Isaac , Karlin Kenneth D. 
Published: December 2014

AbstractDuring the last few decades, copper‐dioxygen chemistry has emerged as a new and very active field of (bio)inorganic relevance. Highlighted herein are the major findings, including the principles of dioxygen activation in metal‐containing proteins along with characterization and reactivity of natural copper‐peroxo systems which are derived from reaction of molecular oxygen with copper(I) active‐site centers. Inspired by the varied array of copper proteins‐enzymes which have been characterized, synthetic bioinorganic researchers have developed model systems which are amenable to facilitating the electron‐transfer and atom‐transfer chemistry which pervades dioxygen binding to copper complexes found in various oxidation states (+1 to +3). These studies have provided for new coordination chemistry of fundamental importance. In addition, significant contributions concerning the identity of biological or chemical reactive intermediates and insights into copper enzyme reaction mechanisms have been made. Taking advantage of this rich redox chemistry, synthetic methods combining copper and O2 (or H2O2) have been explored by organic/inorganic chemists, seeking to employ this earth abundant element to replace routes now usually carried out with precious (expensive/non‐benign) metals, developing green, sustainable and selective oxidative processes.
1,1‐Dihydroperoxides
Authors: Schwartz Chris , Dussault Patrick H. 
Published: December 2014

Abstract

Gem
‐dihydroperoxides (
g
‐DHPs), often referred to as 1,1‐dihydroperoxides, are a class of molecules of interest because of their reactivity as well as their utility as synthetic reagents and intermediates. This review begins with a listing of previous reviews and commercially available
g
‐DHPs, followed by a brief discussion of safety and regulatory issues. The properties of
g
‐DHPs are then overviewed, with an emphasis on the physical properties, biological activity, thermal stability, spectroscopic properties, and behavior on chromatographic media. The remaining sections describe the synthesis and reactions of
g
‐DHPS. The largest of these sections describes the various methods for synthesis of
g
‐DHPs based upon class of catalyst or reagent and compares applications of different reagents selected target skeletons. One of the most significant applications of
g
‐DHPs, their use as precursors for 1,2,4,5‐tetraoxanes, is discussed in detail, including tabular comparisons of approaches to selected skeletons. The chapter concludes with a discussion of other important reactions of
g
‐DHPs, including alkylations, nucleophilic and electrophile‐promoted additions to alkenes, acetalizations, acylations and acylation‐promoted fragmentations, acid‐promoted dimerizations and decompositions, silylations, and application as oxygen transfer agents.
Gas‐Phase Ion Chemistry of Organic Peroxides
Authors: Kato Shuji , Blanksby Stephen J. 
Published: December 2014

Abstract
Over the last 30 years, mass spectrometry and allied technologies have provided significant new insights into the intrinsic, gas phase properties of organic peroxides. In this chapter, the formation and interrogation of neutral peroxides, and their ionized analogues in the gas phase are discussed for several key classes of organic peroxides. Methods for the formation of intact, gas phase cations and anions from labile, often nonvolatile, peroxides using conventional and contemporary soft ionization techniques are described. Studies of the unimolecular dissociation of these ionized peroxides are shown to yield new understanding of energetics and bonding as well as providing diagnostic markers for the elucidation of molecular structure. The bimolecular chemistries of peroxides in the gas phase are considered in two categories: (i) reactions of ions with neutral peroxides; and (ii) the reactions of deprotonated organic hydroperoxides with neutral substrates. Advanced topics cover analytical applications of chemical ionization to the detection of peroxides and peroxyl radicals along with the synthesis of distonic peroxyl radical ions. Studies of the gas phase spectroscopy of organic peroxides that exploit the ionized forms of the peroxides are reviewed including negative‐ion photoelectron spectroscopy, infrared multiple photon dissociation and action spectroscopy.
Gold‐Catalyzed Hydroarylating Cyclization of 1,2‐Bis(2‐iodoethynyl)benzenes
Authors: Nösel Pascal , Müller Vanessa , Mader Steffen , Moghimi Setareh , Rudolph Matthias , Braun Ingo , Rominger Frank , Hashmi A. Stephen K. 
Published: December 2014

Abstract1,5‐Diynes bearing halogen‐substituted alkynes were synthesized and converted in the presence of a gold catalyst. In contrast to the corresponding hydroarylating aromatization reaction with terminal alkynes, a totally different reaction mode was observed. Instead of the expected dual catalysis pathway, only one gold center is needed and a 1,2‐halogen migration is initiated in which either a gold vinylidene species or a gold carbenoid is involved. By the incorporation of one solvent molecule, diiodinated aromatic products are obtained in high selectivity.magnified image
Potassium Iodide‐Catalyzed Three‐Component Synthesis of 2‐Arylquinazolines via Amination of Benzylic CH Bonds of Methylarenes
Authors: Zhao Dan , Shen Qi , Li Jian‐Xin 
Published: December 2014

AbstractA novel potassium iodide‐catalyzed three‐component synthesis of quinazolines via benzylic CH bonds amination was developed. Commonly used ammonia salt and the sp3 carbon in commercially available methylarenes were used as nitrogen and C1 sources, respectively. Mechanistic studies indicated that an aryl aldehyde is involved as a key intermediate in the reaction.magnified image
Human rhinovirus serotypes in the nasal washes and mucosa of patients with chronic rhinosinusitis
Authors: Lee Sung Bu , Yi Jong Sook , Lee Bong‐Jae , Gong Chang‐Hoon , Kim Nam Hee , Joo Chul Hyun , Jang Yong Ju 
Published: December 2014

BackgroundChronic rhinosinusitis (CRS) can be aggravated by viral upper respiratory infections. We aimed to investigate whether any specific human rhinovirus (HRV) serotype is more common in the mucosa of CRS patients, and to find any defining clinical characteristics, according to the various HRV serotypes.MethodsA prospective case‐control study was conducted to determine HRV serotypes in 111 CRS patients and 51 non‐CRS controls. No participant had a history of upper respiratory infection over a 4‐week period. Nasal lavage fluids and turbinate epithelial cells were collected prospectively. When HRV was detected with multiplex polymerase chain reaction (PCR), strains were further characterized by sequencing the VP4/VP2 region of the HRV genome.ResultsHRV was detected in 40 CRS subjects (36%) and 11 non‐CRS controls (21%). The overall detection rates of HRV in CRS patients were higher than in non‐CRS controls (p < 0.05). Of the 8 serotypes detected in CRS patients, 5 belonged to HRV‐A and 3 belonged to HRV‐B; HRV‐C was not detected. In non‐CRS controls, only HRV‐A was identified, with only 2 serotypes detected (HRV‐A13 and HRV‐A16). HRV‐B and C were not detected.ConclusionThe high prevalence of HRV in CRS patients was confirmed in our study. However, we were unable to determine whether certain HRV serotypes are more predominant in CRS patients than non‐CRS controls. HRV‐A13 was the most common serotype in both CRS patients and non‐CRS controls. We could not find any differences in the clinical characteristics according to the HRV serotypes in CRS patients.
Caribbean Integration—Lessons for the Pacific?
Authors: Warner Robert , Anatol Marlon 
Published: December 2014

AbstractThe members of the Pacific Islands Forum have recently considered a quite critical review of the Pacific Plan for strengthening regional cooperation and integration. The Caribbean Community (CARICOM), another grouping encompassing a number of small island developing states, has also been contemplating highly critical assessments of the nature of its approach to regionalism, and of the institutions that have been put in place to give effect to this approach. Are there lessons for the Pacific from the Caribbean experience? This article looks at aspects of the approaches to regionalism and economic integration adopted in the Caribbean, and considers parallels with the situation in the Pacific. It suggests that the CARICOM experience puts into question elements of the logic and overall approach to integration being pursued in both regions (and being urged by external partners).
Tofacitinib Facilitates the Expansion of Myeloid‐Derived Suppressor Cells and Ameliorates Arthritis in SKG Mice
Authors: Nishimura Keisuke , Saegusa Jun , Matsuki Fumichika , Akashi Kengo , Kageyama Goichi , Morinobu Akio 
Published: December 2014

ObjectiveMyeloid‐derived suppressor cells (MDSCs) are a heterogeneous population of cells that have the ability to suppress T cell responses. The aim of this study was to evaluate the effects of the JAK inhibitor tofacitinib on MDSCs in a mouse model of rheumatoid arthritis.MethodsArthritis was induced in SKG mice by zymosan A (ZyA) injection. MDSCs isolated from the bone marrow (BM) of donor SKG mice with arthritis were adoptively transferred to recipient mice with arthritis. In a separate experiment, tofacitinib was administered to arthritic SKG mice subcutaneously via osmotic pump, in some cases followed by injection of an anti–Gr‐1 monoclonal antibody (mAb). BM cells from untreated mice were cultured for 5 days with granulocyte–macrophage colony‐stimulating factor, with or without tofacitinib, and then analyzed by flow cytometry.ResultsThe numbers of MDSCs and polymorphonuclear MDSCs (PMN‐MDSCs) were significantly increased in the spleens of SKG mice following ZyA injection. Adoptive transfer of MDSCs to recipient arthritic mice reduced the severity of arthritis compared to that in untreated control mice. Treatment with tofacitinib also ameliorated the progression of arthritis in SKG mice and induced significantly higher numbers of MDSCs and PMN‐MDSCs in the BM of these animals. Furthermore, administration of an anti–Gr‐1 mAb reduced the antiarthritic effect of tofacitinib in SKG mice. In vitro, tofacitinib facilitated the differentiation of BM cells to MDSCs, and inhibited their differentiation to dendritic cells.ConclusionTofacitinib facilitates the expansion of MDSCs and ameliorates arthritis in SKG mice.
Randomized Controlled Trial of Adalimumab in Patients With Nonpsoriatic Peripheral Spondyloarthritis
Authors: Mease Philip , Sieper Joachim , Van den Bosch Filip , Rahman Proton , Karunaratne P. Mahinda , Pangan Aileen L. 
Published: December 2014

ObjectiveTo evaluate the efficacy and safety of adalimumab in patients with active nonpsoriatic peripheral spondyloarthritis (SpA).MethodsABILITY‐2 is an ongoing phase III, multicenter study of adalimumab treatment. Eligible patients age ≥18 years fulfilled the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for peripheral SpA, did not have a prior diagnosis of psoriasis, psoriatic arthritis (PsA), or ankylosing spondylitis (AS), and had an inadequate response or intolerance to nonsteroidal antiinflammatory drugs (NSAIDs). Patients were randomized 1:1 to receive adalimumab 40 mg every other week or matching placebo for 12 weeks, followed by a 144‐week open‐label period. The primary end point was the proportion of patients achieving 40% improvement in disease activity according to the Peripheral SpA Response Criteria (PSpARC40) at week 12. This was defined as ≥40% improvement from baseline (≥20‐mm absolute improvement on a visual analog scale) in patient's global assessments of disease activity and pain, and ≥40% improvement in at least one of the following features: swollen joint and tender joint counts, total enthesitis count, or dactylitis count. Adverse events were recorded throughout the study.ResultsIn total, 165 patients were randomized to a treatment group, of whom 81 were randomized to receive placebo and 84 to receive adalimumab. Baseline demographics and disease characteristics were generally similar between the 2 groups. At week 12, a greater proportion of patients receiving adalimumab achieved a PSpARC40 response compared to patients receiving placebo (39% versus 20%; P = 0.006). Overall, improvement in other outcomes was greater in the adalimumab group compared to the placebo group. The rates of adverse events were similar in both treatment groups.ConclusionTreatment with adalimumab ameliorated the signs and symptoms of disease and improved physical function in patients with active nonpsoriatic peripheral SpA who exhibited an inadequate response or intolerance to NSAIDs, with a safety profile consistent with that observed in patients with AS, PsA, or other immune‐mediated diseases.
Ca2+ and Mg2+ binding site engineering increases the degradation of polyethylene terephthalate films by polyester hydrolases from Thermobifida fusca
Authors: Then Johannes , Wei Ren , Oeser Thorsten , Barth Markus , Belisário‐Ferrari Matheus R. , Schmidt Juliane , Zimmermann Wolfgang 
Published: December 2014

AbstractSeveral bacterial polyester hydrolases are able to hydrolyze the synthetic polyester polyethylene terephthalate (PET). For an efficient enzymatic degradation of PET, reaction temperatures close to the glass transition temperature of the polymer need to be applied. The esterases TfH, BTA2, Tfu_0882, TfCut1, and TfCut2 produced by the thermophilic actinomycete Thermobifida fusca exhibit PET‐hydrolyzing activity. However, these enzymes are not sufficiently stable in this temperature range for an efficient degradation of post‐consumer PET materials. The addition of Ca2+ or Mg2+ cations to the enzymes resulted in an increase of their melting points between 10.8 and 14.1°C determined by circular dichroism spectroscopy. The thermostability of the polyester hydrolases was sufficient to degrade semi‐crystalline PET films at 65°C in the presence of 10 mM Ca2+ and 10 mM Mg2+ resulting in weight losses of up to 12.9% after a reaction time of 48 h. The residues Asp174, Asp204, and Glu253 were identified by molecular dynamics simulations as potential binding residues for the two cations in TfCut2. This was confirmed by their substitution with arginine, resulting in a higher thermal stability of the corresponding enzyme variants. The generated variants of TfCut2 represent stabilized catalysts suitable for PET hydrolysis reactions performed in the absence of Ca2+ or Mg2+.
An ultra scale‐down analysis of the recovery by dead‐end centrifugation of human cells for therapy
Authors: Delahaye M. , Lawrence K. , Ward S. J. , Hoare M. 
Published: December 2014

ABSTRACTAn ultra scale‐down method is described to determine the response of cells to recovery by dead‐end (batch) centrifugation under commercially defined manufacturing conditions. The key variables studied are the cell suspension hold time prior to centrifugation, the relative centrifugal force (RCF), time of centrifugation, cell pellet resuspension velocities, and number of resuspension passes. The cell critical quality attributes studied are the cell membrane integrity and the presence of selected surface markers. Greater hold times and higher RCF values for longer spin times all led to the increased loss of cell membrane integrity. However, this loss was found to occur during intense cell resuspension rather than the preceding centrifugation stage. Controlled resuspension at low stress conditions below a possible critical stress point led to essentially complete cell recovery even at conditions of extreme centrifugation (e.g., RCF of 10000 g for 30 mins) and long (~2 h) holding times before centrifugation. The susceptibility to cell loss during resuspension under conditions of high stress depended on cell type and the age of cells before centrifugation and the level of matrix crosslinking within the cell pellet as determined by the presence of detachment enzymes or possibly the nature of the resuspension medium. Changes in cell surface markers were significant in some cases but to a lower extent than loss of cell membrane integrity. Biotechnol. Bioeng. 2015;112: 997–1011. © 2014 Wiley Periodicals, Inc.
A framework for real‐time glycosylation monitoring (RT‐GM) in mammalian cell culture
Authors: Tharmalingam Tharmala , Wu Chao‐Hsiang , Callahan Susan , T. Goudar Chetan 
Published: December 2014

ABSTRACTGlycosylation is a critical characteristic of biotherapeutics because of its central role in in vivo efficacy. Multiple factors including medium composition and process conditions impact protein glycosylation and characterizing cellular response to these changes is essential to understand the underlying relationships. Current practice typically involves glycosylation characterization at the end of a fed‐batch culture, which in addition to being an aggregate of the process, reflects a bias towards the end of the culture where a majority of the product is made. In an attempt to rigorously characterize the entire time‐course of a fed‐batch culture, a real‐time glycosylation monitoring (RT‐GM) framework was developed. It involves using the micro sequential injection (μSI) system as a sample preparation platform coupled with an ultra‐performance liquid chromatography (UPLC) system for real‐time monitoring of the antibody glycan profile. Automated sampling and sample preparations were performed using the μSI system and this framework was used to study manganese (Mn)‐induced glycosylation changes over the course of a fed‐batch culture. As expected, Mn‐supplemented cultures exhibited higher galactosylation levels compared to control while the fucosylation and mannosylation were consistent for both supplemented and control cultures. Overall, the approach presented in the study allows real time monitoring of glycosylation changes and this information can be rapidly translated into process control and/or process optimization decisions to accelerate process development. Biotechnol. Bioeng. 2015;112: 1146–1154. © 2014 Wiley Periodicals, Inc.
Expression levels of chaperones influence biotransformation activity of recombinant Escherichia coli expressing Micrococcus luteus alcohol dehydrogenase and Pseudomonas putida Baeyer–Villiger monooxygenase
Authors: Baek A‐Hyong , Jeon Eun‐Yeong , Lee Sun‐Mee , Park Jin‐Byung 
Published: December 2014

ABSTRACTWe demonstrated for the first time that the archaeal chaperones (i.e., γ‐prefoldin and thermosome) can stabilize enzyme activity in vivo. Ricinoleic acid biotransformation activity of recombinant Escherichia coli expressing Micrococcus luteus alcohol dehydrogenase and the Pseudomonas putida KT2440 Baeyer–Villiger monooxygenase improved significantly with co‐expression of γ‐prefoldin or recombinant themosome originating from the deep‐sea hyperthermophile archaea Methanocaldococcus jannaschii. Furthermore, the degree of enhanced activity was dependent on the expression levels of the chaperones. For example, whole‐cell biotransformation activity was highest at 12 µmol/g dry cells/min when γ‐prefoldin expression level was approximately 46% of the theoretical maximum. This value was approximately two‐fold greater than that in E. coli, where the γ‐prefoldin expression level was zero or set to the theoretical maximum. Therefore, it was assumed that the expression levels of chaperones must be optimized to achieve maximum biotransformation activity in whole‐cell biocatalysts. Biotechnol. Bioeng. 2015;112: 889–895. © 2014 Wiley Periodicals, Inc.
Long‐chain alkane production by the yeast Saccharomyces cerevisiae
Authors: Buijs Nicolaas A , Zhou Yongjin J. , Siewers Verena , Nielsen Jens 
Published: December 2014

ABSTRACTIn the past decade industrial‐scale production of renewable transportation biofuels has been developed as an alternative to fossil fuels, with ethanol as the most prominent biofuel and yeast as the production organism of choice. However, ethanol is a less efficient substitute fuel for heavy‐duty and maritime transportation as well as aviation due to its low energy density. Therefore, new types of biofuels, such as alkanes, are being developed that can be used as drop‐in fuels and can substitute gasoline, diesel, and kerosene. Here, we describe for the first time the heterologous biosynthesis of long‐chain alkanes by the yeast Saccharomyces cerevisiae. We show that elimination of the hexadecenal dehydrogenase Hfd1 and expression of a redox system are essential for alkane biosynthesis in yeast. Deletion of HFD1 together with expression of an alkane biosynthesis pathway resulted in the production of the alkanes tridecane, pentadecane, and heptadecane. Our study provides a proof of principle for producing long‐chain alkanes in the industrial workhorse S. cerevisiae, which was so far limited to bacteria. We anticipate that these findings will be a key factor for further yeast engineering to enable industrial production of alkane based drop‐in biofuels, which can allow the biofuel industry to diversify beyond bioethanol. Biotechnol. Bioeng. 2015;112: 1275–1279. © 2014 Wiley Periodicals, Inc.