bluuebunny/crossref_metadata_2025 huggingface dataset:
Structures and Reactivity of Radicals Followed by Magnetic Resonance
Authors: Yurkovskaya Alexandra , Morozova Olga , Gescheidt Georg
Published: March 2012

This chapter introduces methods that allow real‐time observation of short‐lived radicals and radical ions at a nanosecond‐to‐microsecond time scale. CIDNP (Chemically induced dynamic nuclear polarization) and CIDEP (chemically induced dynamic electron polarization or time‐resolved EPR) provide structural details of short‐lived paramagnetic species and insights into reaction kinetics. The basis of these methods is introduced on a phenomenological basis and their scope is illustrated by several examples ranging from organic radicals to polymerization and biomolecular transformations. The aim of this chapter is to present the broad applicability of these methods in a variety of contexts.
Unusual Cyclizations
Authors: Gilmore Kerry , Alabugin Igor V.
Published: March 2012

Although many radical cyclizations play prominent roles in organic synthesis and an ever increasing body of fundamental information aids in the constant development of new radical processes, a number of cyclization modes remain underrepresented. Such “unusual” gaps in the arsenal of available transformations exist for a variety of ring sizes. For example, even fast and stereoelectronically favorable 3‐exo and 4‐exo cyclizations are often rendered impossible by the high thermodynamic cost for the formation of strained small cycles. In contrast, 5‐endo cyclizations are exothermic but disfavored stereoelectronically and often slow. Moreover, even the most common five‐ or six‐membered rings are often made via an unusual class of cycloaromatization reactions where radical formation from a nonradical precursor is coupled with the cyclization step. A new set of problems appears for the formation of larger rings where the cyclizations are disfavored entropically.

Additionally, certain factors disfavor even the well‐represented cyclization topologies, independent on the ring size. In particular, most cyclic closures involve carbon‐carbon bond formation via carbon radical addition to an alkene or alkyne, whereas radical ring closure via the formation of C‐heteroatom bonds are relatively scarce. We expand our discussion to radical cyclizations that proceed via CO and CN bond formation, which often provide an efficient approach to the construction of heterocycles.

In our discussion, we highlight a number of factors that are useful for promoting unusual cyclizations: destabilization of reactants, stabilization of the cyclic products, electronic and conformational effects on the transition states, as well as coupling of thermodynamically unfavorable events with highly exothermic follow‐up steps.
Main‐Group Elements in Radical Chemistry
Authors: Baralle Alexandre , Baroudi Abdulkader , Daniel Marion , Fensterbank Louis , Goddard Jean‐Philippe , Lacôte Emmanuel , Larraufie Marie‐Hélène , Maestri Giovanni , Malacria Max , Ollivier Cyril
Published: March 2012

This article deals with the radical chemistry of main‐group elements, which has been a particularly active field over the last decade. More specifically, we have dealt with the recent synthetic advances involving nitrogen‐, oxygen‐, phosphorus‐, sulfur‐, and selenium‐centered radicals. Modes of generation of these highly reactive entities have witnessed tremendous developments and their various uses have been treated exhaustively. Mechanistic scenarios have been thoroughly discussed, and stereoselectivity issues, including asymmetric processes, have been addressed. Whenever possible, illustrative applications in the total synthesis of natural products or molecules with relevant properties have been introduced.
Xanthates and Related Derivatives as Radical Precursors
Authors: Zard Samir Z.
Published: March 2012

This chapter deals with the various radical reactions involving dithiocarbonates (xanthates) and related structures. It will revolve around two main topics: (i) cleavage of the CO bond and (ii) cleavage of the CS bond.

The first mode corresponds to the Barton–McCombie reaction and variants thereof. The mechanism of this important reaction is discussed in detail and then illustrated with a few varied examples taken from the recent literature (in order not to overlap too much with existing reviews). Modifications not using organotin hydrides are also described, with emphasis on the practical aspects. The incorporation of the Barton–McCombie process in various CC bond‐forming radical sequences is also be presented. Included in this part is an O → S radical chain rearrangement that is sometimes observed.

The second mode encompasses the degenerative fragmentation of xanthates. Radicals generated this way have a relatively long lifetime in the medium, allowing various transformations otherwise difficult to perform. Intermolecular additions to unactivated olefins are one such case. The possibility of using the adduct, itself a xanthate, for another radical sequence can also be exploited. Intra‐ and intermolecular additions to aromatic and heteroaromatic rings, as well as radical‐based modifications of the xanthate group, are other possibilities that are described and illustrated with examples.
Radical Enzymes
Authors: Buckel Wolfgang , Golding Bernard T.
Published: March 2012

Radical enzymes catalyze reactions with intermediate radicals, which are not free but bound to the enzyme. The catalytic reactions comprise generation of a radical species that initiates formation of the substrate‐derived radical, followed by conversion to the product‐related radical, and either recycling or decomposition of the initiating radical with release of the product. These characteristics are illustrated with specific radical enzymes. Ribonucleotide reductases (RNRs) use a thiyl radical to enable a common reaction mechanism for the reduction of ribose. There are three classes of RNRs that differ in the manner of thiyl radical generation: use of coenzyme B12,S‐adenosylmethionine (SAM), or dioxygen with bi‐transition metal centers. Coenzyme B12‐dependent eliminases and mutases are like SAM radical enzymes in that they apply the same 5′‐deoxyadenosyl radical as initiating radical, which is also used by coenzyme B12‐ or SAM‐dependent RNRs. The SAM radical enzymes, which multiply in number, are involved in the maturation of enzymes and transfer of ribonucleic acids, as well as in the biosynthesis of many vitamins, coenzymes, and antibiotics. The 2‐ and 4‐hydroxyacyl‐coenzyme A (CoA) dehydratases contain a [4Fe–4S] cluster and utilize intermediate ketyl radicals, which are formed either by reduction or by combined oxidation/deprotonation of the substrates. Similar radical species participate in the reduction of benzoyl‐CoA and other aromatic compounds as well as in photolyases that repair DNA. Finally, flavin radical enzymes and two [4Fe–4S] cluster enzymes of the nonmevalonate pathway of isoprenoid biosynthesis are described. In conclusion, biotechnological applications and evolutionary aspects are discussed.
Supramolecular Radical Chemistry
Authors: Lucarini Marco
Published: March 2012

This report describes both the application of the concepts of supramolecular chemistry to control the reactivity of organic free radical and how electron paramagnetic resonance (EPR) methods have been extensively used for detecting and identifying noncovalent assemblies in solution and for clarifying their structure and properties. It shows how hydrogen bonding can modulate free radical properties; how halogen bonding can be used to prepare supramolecular structures containing nitroxide radicals with particular spin orientations; how the formation of host–guest complexes or the properties of self‐assembled monolayers can be investigated by EPR spectroscopy; and how radical cations can be employed to prepare very sophisticated molecular devices. Finally, a short description of the effects of confined space such as zeolites on radical–radical reactions is provided.
Classifying web search queries to identify high revenue generating customers
Authors: Ortiz‐Cordova Adan , Jansen Bernard J.
Published: March 2012

Traffic from search engines is important for most online businesses, with the majority of visitors to many websites being referred by search engines. Therefore, an understanding of this search engine traffic is critical to the success of these websites. Understanding search engine traffic means understanding the underlying intent of the query terms and the corresponding user behaviors of searchers submitting keywords. In this research, using 712,643 query keywords from a popular Spanish music website relying on contextual advertising as its business model, we use a k‐means clustering algorithm to categorize the referral keywords with similar characteristics of onsite customer behavior, including attributes such as clickthrough rate and revenue. We identified 6 clusters of consumer keywords. Clusters range from a large number of users who are low impact to a small number of high impact users. We demonstrate how online businesses can leverage this segmentation clustering approach to provide a more tailored consumer experience. Implications are that businesses can effectively segment customers to develop better business models to increase advertising conversion rates.
Photoinduced Electron Transfer from the Inorganic Core to the Organic Shell of Hybrid Core–Shell Nanoparticles: Impedance Spectroscopy
Authors: Guchhait Asim , Pal Amlan J.
Published: March 2012

In hybrid core–shell nanoparticles with inorganic nanocrystals in the core and organic molecules in the shell, photoinduced electron transfer occurs from the core to the shell. This leads to exciton dissociation through an ultrafast electron‐transfer process that results in charge separation and finally photocurrent in the external circuit in devices based on such core–shell nanoparticles. In this work, we have fabricated and characterized sandwiched devices based on a series of core–shell systems. From impedance spectroscopy, we have observed that photoinduced charge separation in core–shell systems is associated with a decrease in the device resistance and an increase in the dielectric constant of the active material. In the series of core–shell systems, we have observed a one‐to‐one correlation between the photoinduced electron‐transfer process and the changes in resistive and dielectric parameters upon illumination.
Clinical and biomarker profile of trauma-induced secondary cardiac injury
Authors: De'Ath H D , Rourke C , Davenport R , Manson J , Renfrew I , Uppal R , Davies L C , Brohi K
Published: March 2012

Background

Secondary cardiac injury has been demonstrated in critical illness and is associated with worse outcomes. The aim of this study was to establish the existence of trauma-induced secondary cardiac injury, and investigate its impact on outcomes in injured patients.

Methods

Injured adult patients eligible for enrolment in the Activation of Coagulation and Inflammation in Trauma 2 study, and admitted to the intensive care unit between January 2008 and January 2010, were selected retrospectively for the study. Markers of cardiac injury (brain natriuretic peptide (BNP), heart-type fatty acid binding protein (H-FABP) and troponin I) were measured on admission, and after 24 and 72 h in blood samples from injured patients. Individual records were reviewed for adverse cardiac events and death.

Results

During the study period, 135 patients were enrolled (106 male, 78·5 per cent) with a median age of 40 (range 16–89) years. Eighteen patients (13·3 per cent) had an adverse cardiac event during admission and these events were not associated with direct thoracic injury. The in-hospital mortality rate was higher among the adverse cardiac event cohort: 44 per cent (8 of 18) versus 17·1 per cent (20 of 117) (P = 0·008). Raised levels of H-FABP and BNP at 0, 24 and 72 h, and troponin I at 24 and 72 h, were associated with increased adverse cardiac events. BNP levels were higher in non-survivors on admission (median 550 versus 403 fmol/ml; P = 0·022), after 24 h (794 versus 567 fmol/ml; P = 0·033) and after 72 h (1043 versus 753 fmol/ml; P = 0·036), as were admission troponin I levels.

Conclusion

Clinical and cardiac biomarker characteristics support the existence of trauma-induced secondary cardiac injury, which is associated with death, and unrelated to direct thoracic injury.
Biosynthesis of Xyrrolin, a New Cytotoxic Hybrid Polyketide/Non‐ribosomal Peptide Pyrroline with Anticancer Potential, in Xylaria sp. BCC 1067
Authors: Phonghanpot Suranat , Punya Juntira , Tachaleat Anuwat , Laoteng Kobkul , Bhavakul Vanida , Tanticharoen Morakot , Cheevadhanarak Supapon
Published: March 2012

A gene from Xylaria sp. BCC 1067, pks3, that encodes a putative 3660‐residue hybrid polyketide synthase (PKS)/non‐ribosomal peptide synthetase (NRPS) was characterised by targeted gene disruption in combination with comprehensive product identification. Studies of the features of a corresponding mutant, YA3, allowed us to demonstrate that pks3 is responsible for the synthesis of a new pyrroline compound, named xyrrolin, in the wild‐type Xylaria sp. BCC 1067. The structure of xyrrolin was established by extensive spectroscopic and spectrometric analyses, including low‐ and high‐resolution MS, IR, 1H NMR, 13C NMR, 13C NMR with Dept135, HMQC 2D NMR, HMBC 2D NMR and COSY 2D NMR. On the basis of the Pks3 domain organisation and the chemical structure of xyrrolin, we proposed that biosynthesis of this compound requires the condensation of a tetraketide and an L‐serine unit, followed by Dieckmann or reductive cyclisation and enzymatic removal of ketone residue(s). Bioassays of the pure xyrrolin further displayed cytotoxicity against an oral cavity (KB) cancer cell line.
Disposable Electrochemical Immunosensor by Using Carbon Sphere/Gold Nanoparticle Composites as Labels for Signal Amplification
Authors: Xu Qiunan , Yan Feng , Lei Jianping , Leng Chuan , Ju Huangxian
Published: March 2012

This work designed a simple, sensitive, and low‐cost immunosensor for the detection of protein marker by using a carbon sphere/gold nanoparticle (CNS/AuNP) composite as an electrochemical label. The nanoscale carbon spheres, prepared with a hydrothermal method by using glucose as raw material, were used to load AuNPs for labeling antibody by electrostatic interaction, which provided a feasible pathway for electron transfer due to the remarkable conductivity. The disposable immunosensor was constructed by coating a polyethylene glycol (PEG) film on a screen‐printed carbon‐working electrode and then immobilizing capture antibody on the film. With a sandwich‐type immunoassay format, the analyte and then the CNS/AuNP‐labeled antibody were successively bound to the immunosensor. The bound AuNPs were finally electro‐oxidized in 0.1 M HCl to produce AuCl4− for differential pulse voltammetric (DPV) detection. The high‐loading capability of AuNPs on CNS for the sandwich‐type immunorecognition led to obvious signal amplification. By using human immunoglobulin G (IgG) as model target, the DPV signal of AuNPs after electro‐oxidized at optimal potential of +1.40 V for 40 s showed a wide linear dependence on the logarithm of target concentration ranging from 10 pg mL−1 to 10 ng mL−1. The detection limit was around 9 pg mL−1. The immunosensor showed excellent analytical performance with cost effectivity, good fabrication reproducibility, and acceptable precision and accuracy, providing significant potential application in clinical analysis.
Pemetrexed in combination with cisplatin versus cisplatin monotherapy in patients with recurrent or metastatic head and neck cancer
Authors: Urba Susan , van Herpen Carla M. L. , Sahoo Tarini Prasad , Shin Dong M. , Licitra Lisa , Mezei Klara , Reuter Christoph , Hitt Ricardo , Russo Francesca , Chang Shao‐Chun , Hossain Anwar M. , Frimodt‐Moller Bente , Koustenis Andrew , Hong Ruey‐Long
Published: March 2012

BACKGROUND:

Recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN) is associated with poor survival. Platinum‐based chemotherapy is often a first‐line treatment. Pemetrexed has shown single‐agent activity in SCCHN and in combination with cisplatin for other tumors. This trial examined the efficacy of pemetrexed‐cisplatin for SCCHN.

METHODS:

In a double‐blind phase 3 trial, patients with recurrent or metastatic SCCHN and no prior systemic therapy for metastatic disease were randomized to pemetrexed (500 mg/m2) plus cisplatin (75 mg/m2; n = 398) or placebo plus cisplatin (75 mg/m2; n = 397) to assess overall survival (OS) and secondary endpoints.

RESULTS:

Median OS was 7.3 months in the pemetrexed‐cisplatin arm and 6.3 months in the placebo‐cisplatin arm (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.75‐1.02;P= .082). Median progression‐free survival (PFS, months) was similar in both treatment arms (pemetrexed‐cisplatin, 3.6; placebo‐cisplatin, 2.8; HR, 0.88; 95% CI, 0.76‐1.03;P= .166). Among patients with performance status 0 or 1, pemetrexed‐cisplatin (n = 347) led to longer OS and PFS than placebo‐cisplatin (n = 343; 8.4 vs 6.7 months; HR, 0.83;P= .026; 4.0 vs 3.0 months; HR, 0.84;P= .044, respectively). Among patients with oropharyngeal cancers, pemetrexed‐cisplatin (n = 86) resulted in longer OS and PFS than placebo‐cisplatin (n = 106; 9.9 vs 6.1 months; HR, 0.59;P= .002; 4.0 vs 3.4 months; HR, 0.73;P= .047, respectively). Pemetrexed‐cisplatin toxicity was consistent with studies in other tumors.

CONCLUSIONS:

Pemetrexed‐cisplatin compared with placebo‐cisplatin did not significantly improve survival for the intent‐to‐treat population. However, in a prespecified subgroup analysis, pemetrexed‐cisplatin showed OS and PFS advantage for patients with performance status 0 or 1 or oropharyngeal cancers. Cancer 2012. © 2012 American Cancer Society.
Clinical and histopathologic characteristics of rash in cancer patients treated with mammalian target of rapamycin inhibitors
Authors: Balagula Yevgeniy , Rosen Alyx , Tan Belinda H. , Busam Klaus J. , Pulitzer Melissa P. , Motzer Robert J. , Feldman Darren R. , Konner Jason A. , Reidy‐Lagunes Diane , Myskowski Patricia L. , Lacouture Mario E.
Published: March 2012

BACKGROUND:

Dermatologic adverse events stemming from anticancer therapies have become an increasingly frequent clinical problem. Inhibitors of mammalian target of rapamycin (mTOR), such as temsirolimus and everolimus, have been associated with a high rate of skin eruptions, but their clinical and histopathologic characteristics have not been explored.

METHODS:

A retrospective analysis of patients who were referred to the Dermatology Service for diagnosis and management of rash in the setting of therapy with the mTOR inhibitors everolimus and temsirolimus was performed. The parameters that were studied included the time to onset, clinical presentation at the time of dermatologic evaluation, associated symptoms, evolution, results of microbiologic studies, concomitant medications, the need for dose reduction and/or treatment interruption because of rash, and routine histopathology.

RESULTS:

In total, 13 patients were analyzed. Most rashes were mild (grade 1; 31%) and moderate (grade 2; 54%) in severity, and grade 3 rashes were observed only in 2 patients (15%). The trunk was the most frequently affected region (77%), with the scalp (23%), face (38%), neck (54%), and extremities (69%) also commonly involved. Erythematous papules and pustules constituted the predominant primary lesion morphology (62%). No unique or uniform histopathologic reaction pattern was observed. The most common reaction pattern was that of a mixed, spongiotic interface and perivascular dermatitis, which was observed in 7 of 11 patients (63%).

CONCLUSIONS:

Although mTOR inhibitors may commonly induce erythematous papules and pustules, they are associated with a spectrum of lesion morphologies and a variety of histopathologic findings. Further clinicohistologic correlation studies are needed. Cancer 2012. © 2012 American Cancer Society.
Racial differences in presentation and management of follicular non‐Hodgkin lymphoma in the United States
Authors: Nabhan Chadi , Byrtek Michelle , Taylor Michael D. , Friedberg Jonathan W. , Cerhan James R. , Hainsworth John D. , Miller Thomas P. , Hirata Jamie , Link Brian K. , Flowers Christopher R.
Published: March 2012

BACKGROUND:

Racial differences in follicular lymphoma (FL) in the United States have not been investigated.

METHODS:

The National LymphoCare Study is a multicenter, longitudinal, observational cohort study collecting data on treatment patterns and outcomes for patients with newly diagnosed FL in the United States between 2004 and 2007 without any predefined, study‐specific intervention. The authors investigated differences between white (W) patients, African American (AA) patients, and Hispanic (H) patients.

RESULTS:

Among 2744 enrolled patients, there were 95 (3%) AA patients, 125 (5%) H patients, and 2476 (90%) W patients. Compared with W patients, more AA and H patients were diagnosed at age <45 years (P < .0001). H patients more commonly were diagnosed with grade 3 FL compared with AA and W patients (29%, 13%, and 18%, respectively; P = .019) and more commonly received rituximab plus chemotherapy as initial therapy compared with W patients (66% vs 50%; P = .036), while AA patients less commonly received anthracyclines (49% vs 64% in W patients; P = .027). H and AA patients who received rituximab plus chemotherapy were less likely than W patients to receive maintenance rituximab (27% vs 31% vs 40%, respectively; P = .031). At a median follow‐up of 52 months, progression‐free survival was similar between AA and W patients but was longer in H patients, and there was no difference in overall survival.

CONCLUSIONS:

In the largest prospective cohort to date of AA and H patients with FL in the United States, AA and H patients were younger at presentation. Although racial differences in treatment patterns for FL were noted, additional follow‐up is needed to determine the impact of these differences on survival. Cancer 2012. © 2012 American Cancer Society.
New frontiers in cell competition†
Authors: de Beco Simon , Ziosi Marcello , Johnston Laura A.
Published: March 2012

Cellular communication is at the heart of animal development, and guides the specification of cell fates, the movement of cells within and between tissues, and the coordinated arrangement of different body parts. During organ and tissue growth, cell–cell communication plays a critical role in decisions that determine whether cells survive to contribute to the organism. In this review, we discuss recent insights into cell competition, a social cellular phenomenon that selects the fittest cells in a tissue, and as such potentially contributes to the regulation of its growth and final size. The field of cell competition has seen a huge explosion in its study in the last several years, facilitated by the increasingly sophisticated genetic and molecular technology available in Drosophila and driven by its relevance to stem cell biology and human cancer. Developmental Dynamics 241:831–841, 2012. © 2012 Wiley Periodicals, Inc.
Efficient search for Anisimkin's (quasilongitudinal) modes in rotated Y‐cuts of various piezoelectric materials
Authors: Onoe Morio , Kaga Shigetaka
Published: March 2012

Quasilongitudinal modes in a quartz ST cut discovered by Anisimkin gave a new possibility of selecting material for sensing devices. An efficient search method is presented based on analyses previously reported. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(4): 41–48, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10410
Theoretical consideration of high‐sensitivity biosensor using shear horizontal acoustic waves in layered structures
Authors: Kondoh Jun
Published: March 2012

Realization of high‐sensitivity biosensors is required. Acoustic wave‐based biosensors are promising because of their ability to detect immunoreactions. In this paper, a shear horizontal (SH) acoustic wave in layered structures, namely, the Love wave, is discussed on the basis of numerical calculations. To generate the Love wave, a 36YX‐LiTaO3 was chosen as a piezoelectric substrate. SiO2, polymer, and gold were chosen as guiding layer materials. First, the phase velocity and propagation loss were calculated as a function of the layer thickness. Then, an additional mass layer was loaded on the guiding layer to simulate bio‐layer deposition. Simulation results indicate that a highly sensitive biosensor was realized by using a gold guiding layer. © 2012 Wiley Periodicals, Inc. Electron Comm Jpn, 95(4): 27–;32, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10417
Persistent genomic instability in peripheral blood lymphocytes from hodgkin lymphoma survivors
Authors: Salas C. , Niembro A. , Lozano V. , Gallardo E. , Molina B. , Sánchez S. , Ramos S. , Carnevale A. , Pérez‐Vera P. , Rivera Luna R. , Frias S.
Published: March 2012

Advances in cancer treatment have led to an increase in patient survival. However, exposure to genotoxic chemotherapeutic agents and ionizing radiation may induce persistent genetic damage in cancer survivors. In this study, we detected genomic instability in chromosomes of peripheral blood lymphocytes from Hodgkin lymphoma patients, 2–17 years after MOPP (nitrogen mustard, Oncovin, procarbazine, and prednisone) chemotherapy with or without radiotherapy. Samples were obtained from 11 healthy individuals, 5 pretreatment patients, and 20 posttreatment patients. Cytogenetic analysis with GTG banding was performed on 1,000 lymphocyte metaphases per donor to identify genomic instability, including numerical and structural chromosomal aberrations, at a resolution of 10 Mb across the entire genome. Our results showed that anticancer treatment did not induce significant differences in the frequency of aneuploidy among the three study groups. However, 1 of the 11 healthy individuals, and 13 of the 20 posttreatment patients had a high frequency of chromosomal breaks and gross chromosomal rearrangements. The types of aberrations observed were random and complex, consistent with persistent genomic instability that was induced by cancer treatment. Clonal expansion of cells with chromosomal lesions was observed in one posttreatment patient only. These findings show that anticancer treatments induce persistent genomic instability, but not aneuploidy. Chemotherapy may affect genes with a role in DNA damage surveillance or repair, which in turn allows the accumulation of nontargeted structural chromosomal damage in future generations of cells. This genomic instability may facilitate the development of second malignancies in Hodgkin lymphoma survivors. Environ. Mol. Mutagen. 2012. © 2012 Wiley Periodicals, Inc.
Separation of norbixin from Bixa orellana seed raw dye by Aliquat‐336
Authors: Sharma Ponchami , Bora M.M. , Borthakur Samiran , Rao P.G. , Dutta N.N.
Published: March 2012

The reactive extraction of Bixa orellana seed pigment norbixin with cationic carrier Aliquat‐336 (QCl) in a two phase system has been studied. A raw alkali extract of Bixa orellana pigments in 0.5% sodium hydroxide solution is used as aqueous phase and Aliquat‐336 dissolved in hexane as solvent is used as the organic phase. In the aqueous alkaline phase, the pigment (bixin + norbixin) exists as sodium norbixinate in ionized form. This sodium norbixinate forms complex with QCl by an ion‐exchange mechanism which is pH dependent. Re‐extraction occurs via another ion‐exchange reaction with H+ ion with another aqueous phase of low pH. Complexation expressed as degree of extraction increases with pH reaching almost an asymptotic whereafter tends to decrease slightly. Around 99% recovery of norbixin as its complex with Aliquat‐336 was achieved at an organic phase to aqueous phase volume ratio 2:1. 98% of the norbixin‐QCl complex was recovered as norbixin in aqueous solution at pH 4. The results of this investigation may be considered reasonable to believe that reactive extraction is likely to provide an attractive and alternative separation method for the recovery of norbixin. © 2011 American Institute of Chemical Engineers Environ Prog, 32: 134–138, 2013.
Modeling cyclic loading behavior of jointed precast concrete connections including effects of friction, tendon yielding and dampers
Authors: Rodgers Geoffrey W. , Mander John B. , Geoffrey Chase J.
Published: March 2012

Reversed cyclic loading behavior of jointed precast prestressed concrete beam‐to‐column connections are computationally modeled and validated against full‐scale experimental results. Response simulations are performed with and without supplemental high force‐to‐volume (HF2V) energy dissipation devices. The experimental specimen is a three‐dimensional corner connection of a jointed precast concrete frame structure, utilizing unbonded post‐tensioned tendons consisting of high‐alloy, high‐strength thread‐bars. The joint region is armored, to avoid damage, by providing steel plates at the beam–column (rocking) contact points.

The analytical model of the connection is developed to include modifications for the effects of changing connection behavior. These effects are friction within the prestressing system, yielding of the prestressing tendons, reduction or elimination of prestress attributable to prior tendon yield, and directional dependence caused by an asymmetrical prestress system. Particular attention is given to developing a robust model that can accommodate small reversals in the displacement loading. The model is extended to incorporate the effects of the HF2V energy dissipation devices and the associated flexibility from the elements that connect the devices to the structure. Although the model is applied to the use of HF2V (lead extrusion) energy dissipation devices, it is general and can accommodate any non‐linear rate‐dependent damper. The computational model is based almost entirely on rational mechanics and shows good agreement with the full‐scale experimental observations. Copyright © 2012 John Wiley & Sons, Ltd.
Who Makes Markets? Liquidity Providers Versus Algorithmic Traders
Authors: Chae Joon , Khil Jaeuk , Lee Eun Jung
Published: March 2012

We investigate the roles of liquidity providers (LPs) and algorithmic traders (ATs) using a complete derivative warrant trading record of all investors in Korea. The main empirical findings indicate that LPs, the sole traders responsible for making market, do not trade primarily for liquidity provision. Instead, ATs provide liquidity. We further study the profitability of LPs and ATs and decompose their profits into information, market making, and mixed components. The results provide strong evidence that LPs earn profits using information about the future prospects of derivative warrants. ATs, however, are much better at sustaining profits by providing liquidity. Surprisingly, our evidence shows that though LPs earn positive total profits, ATs generally incur losses by trading. © 2012 Wiley Periodicals, Inc. Jrl Fut Mark 33:397‐420, 2013
Complement component C3 and complement receptor type 3 contribute to the phagocytosis and clearance of fibrillar Aβ by microglia
Authors: Fu Hongjun , Liu Bin , Frost Jeffrey L. , Hong Soyon , Jin Ming , Ostaszewski Beth , Shankar Ganesh M. , Costantino Isabel M. , Carroll Michael C. , Mayadas Tanya N. , Lemere Cynthia A.
Published: March 2012

Complement components and their receptors are found within and around amyloid β (Aβ) cerebral plaques in Alzheimer's disease (AD). Microglia defend against pathogens through phagocytosis via complement component C3 and/or engagement of C3 cleavage product iC3b with complement receptor type 3 (CR3, Mac‐1). Here, we provide direct evidence that C3 and Mac‐1 mediate, in part, phagocytosis and clearance of fibrillar amyloid‐β (fAβ) by murine microglia in vitro and in vivo. Microglia took up not only synthetic fAβ42 but also amyloid cores from patients with AD, transporting them to lysosomes in vitro. Fibrillar Aβ42 uptake was significantly attenuated by the deficiency or knockdown of C3 or Mac‐1 and scavenger receptor class A ligands. In addition, C3 or Mac‐1 knockdown combined with a scavenger receptor ligand, fucoidan, further attenuated fibrillar Aβ42 uptake by N9 microglia. Fluorescent fibrillar Aβ42 microinjected cortically was significantly higher in C3 and Mac‐1 knockout mice compared with wild‐type mice 5 days after surgery, indicating reduced clearance in vivo. Together, these results demonstrate that C3 and Mac‐1 are involved in phagocytosis and clearance of fAβ by microglia, providing support for a potential beneficial role for microglia and the complement system in AD pathogenesis. © 2012 Wiley Periodicals, Inc.
Effect of temporal resolution of water level and temperature inputs on numerical simulation of groundwater–surface water flux exchange in a heavily modified urban river
Authors: Ebrahim Girma Yimer , Hamonts Kelly , van Griensven Ann , Jonoski Andreja , Dejonghe Winnie , Mynett Arthur
Published: March 2012

Groundwater interacts with surface water features nearly in all types of landscapes. Understanding these interactions has practical consequences on the quantity and quality of water in either system, because the depletion or contamination of one of the systems will eventually affect the other one. Many studies have shown that the use of heat as natural tracer in conjunction with water level measurements is an effective method for estimating water flow (fluxes) between groundwater and surface water. A number of studies have explored the effects of spatial and temporal variability of groundwater–surface water flux exchanges using temperature and water level measurements; however, the effect of temporal resolution of water level and temperature data on estimating flux remains unexplored. Therefore, this study investigated the effect of temporal resolution of input data on temporal variation of groundwater–surface water flux exchanges. To this end, we calibrated a variably saturated two‐dimensional groundwater flow and heat transport model (VS2DH) at hourly and daily time scales using temperatures measured at multiple depths below the riverbed of the Zenne River, located at a well‐known Belgian brownfield site. Results of the study showed that the computed water flux through the streambed ranged between −32 mm/day and +25 mm/day using the hourly model and from −10 mm/day to −37 mm/day using the daily model. The hourly model resulted in detecting reversal of flow direction inducing short‐term surface water flow into the streambed. However, such events were not captured if daily temperature and water level measurements were used as input. These findings have important implications for understanding contaminant mass flux and their attenuation in the mixing zone of groundwater and surface water. Copyright © 2012 John Wiley & Sons, Ltd.
Zoledronic acid improves bone mineral density in pediatric spinal cord injury
Authors: Ooi Hooi Leng , Briody Julie , McQuade Mary , Munns Craig F
Published: March 2012

Spinal cord injury (SCI) is associated with rapid and sustained bone loss and increase risk of fracture. Disuse is the primary cause for bone loss, although neural and hormonal changes may also contribute via different mechanisms. Bisphosphonates are used widely to treat osteoporosis in adults and are used increasingly for primary and secondary osteoporosis in children. Current data are insufficient to recommend routine use of bisphosphonates for fracture prevention in adult patients post-SCI and there are no available data in pediatric SCI. We report a 12-year-old boy with non-traumatic SCI who was treated with six monthly zoledronic acid (0.05 mg/kg/dose) for 18 months. The patient (AA) was diagnosed with transverse myelitis at 8.1 years of age, resulting in ventilator-dependent incomplete C3 tetraplegia. Following a fragility fracture to the surgical neck of the right humerus at 9.5 years of age, he was started on zoledronic acid. Bone turnover decreased and bone densitometry data (dual-energy X-ray absorptiometry [DXA] and peripheral quantitative computed tomography [pQCT]) showed improvement in metaphyseal and diaphyseal bone mineral content (BMC), volumetric bone mineral density (vBMD), and size, after 18 months of treatment. In the growing skeleton post-SCI, zoledronic acid potentially increases vertebral and long-bone strength by preserving trabecular bone (increased BMC and vBMD) and increasing cortical vBMD and cross-sectional area (CSA). © 2012 American Society for Bone and Mineral Research.
Adjunctive ultrasonography during carotid artery stenting to minimize iodine contrast use
Authors: Nammuni Isuru , Batt Paul , Erlich Jonathan , Varcoe Ramon L.
Published: March 2012

Carotid artery stenting (CAS) in patients with chronic kidney disease carries a significant risk of contrast‐induced nephropathy. We report a case of CAS with adjunctive sonography to reduce the amount of contrast medium during angiography. A 71‐year‐old man presented with a symptomatic right carotid stenosis. He was selected for CAS due to significant medical comorbidity, which included severe renal impairment. A preoperative noncontrast CT was performed to assess anatomical suitability and to plan arch vessel cannulation. We undertook CAS with the use of intraoperative ultrasound. Sonography was used to monitor the manipulation of wires, catheters, and stents. Four milliliters of contrast was required to complete the procedure successfully with no deterioration in postoperative renal function. Adjunctive ultrasound is feasible to reduce contrast use in patients with severe renal impairment undergoing CAS. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 41:323–326, 2013
Employing reduced surface field technique by a P‐type region in 4H‐SiC metal semiconductor field effect transistors for increasing breakdown voltage
Authors: Moghadam Hamid Amini , Orouji Ali A. , Jamali Mahabadi S. E.
Published: March 2012

In this paper, we employ the Reduced Surface Field technique in metal semiconductor field effect transistors (MESFETs) by a P‐type region above the active layer near gate (PR‐MESFET). Electric field distribution can be made more uniform by a new depletion region in the active layer of the proposed structure that is created by a P‐type region. ‏‏Therefore, the electric field peak at the gate edge decreases, and the breakdown voltage increases. On the basis of our simulation results, the breakdown voltage increases as compared with the conventional bulk 4H‐SiC MESFET (CB‐MESFET) and the spacer bulk 4H‐SiC MESFET (SB‐MESFET). Detailed numerical simulations demonstrate that for proposed structure due to decrease in parasitic gate‐to‐drain capacitor, maximum oscillation frequency increases with respect to SB‐MESFET. Our simulation results show that output current slightly decreases in comparison with CB‐MESFET. Copyright © 2012 John Wiley & Sons, Ltd.
Time course of tinnitus development following noise exposure in mice
Authors: Turner Jeremy , Larsen Deb , Hughes Larry , Moechars Diederik , Shore Susan
Published: March 2012

Gap‐induced prepulse inhibition of acoustic startle (GPIAS) has been used in rats and mice to study the problem of tinnitus. The current study demonstrates that similar methods can be used to study the temporal development of tinnitus over time in middle‐aged mice. Six‐month‐old mice on a mixed C57Bl6 × 129 background were anesthetized with isoflurane and exposed to unilateral noise (n = 15), or sham exposure for controls (n = 8), for 1 hr (16‐kHz octave band signal, 116‐dB SPL). Tinnitus was tested in eight different sound frequency bands before and at postexposure time points of 1, 3–4, 7, 14, 21, and 30 days and monthly thereafter until 7 months postexposure. Noise‐exposed mice displayed a number of changes in GPIAS consistent with the presence of hyperacusis and tinnitus. Noise exposure was associated with acute tinnitus measured 1 day later at several frequencies at and above the exposure frequency center. Consistent, chronic tinnitus then emerged in the 24‐kHz range. Several time points following noise exposure suggested evidence of hyperacusis, often followed temporally by the development of deficits in GPIAS (reflecting tinnitus). Temporal development of these changes following noise exposure are discussed in the context of the interactions among aging, noise exposure, and the associated neurochemical changes that occur at early stages of auditory processing. © 2012 Wiley Periodicals, Inc.
Myosin II is a negative regulator of oligodendrocyte morphological differentiation
Authors: Wang Haibo , Rusielewicz Tomasz , Tewari Ambika , Leitman Ellen M. , Einheber Steven , Melendez‐Vasquez Carmen V.
Published: March 2012

During their development as myelinating cells, oligodendrocyte progenitors (OPC) undergo dramatic changes in the organization of their cytoskeleton. These changes involve an increase in cell branching and in lamella extension, which is important for the ability of oligodendrocytes to myelinate multiple axons in the CNS. We have previously shown that the levels of the actin‐associated motor protein nonmuscle myosin II (NMII) decrease as oligodendrocyte differentiate and that inhibition of NMII activity increases branching and myelination, suggesting that NMII is a negative regulator of oligodendrocyte differentiation. In agreement with this interpretation, we have found that overexpression of NMII prevents oligodendrocyte branching and differentiation and that OPC maturation is accelerated in NMII knockout mice as shown by a significant increase in the percentage of mature MBP+ cells. Although several pathways have been implicated in oligodendrocyte morphogenesis, their specific contribution to the regulation of NMII activity has not been directly examined. We tested the hypothesis that the activity of NMII in OPC is controlled by Fyn kinase via downregulation of RhoA‐ROCK‐NMII phosphorylation. We found that treatment with PP2 or knockdown of Fyn using siRNA prevents the decrease in myosin phosphorylation normally observed during OPC differentiation and that the inhibition of branching induced by overexpression of constitutively active RhoA can be reversed by treatment with Y27632 or blebbistatin. Taken together, our results demonstrate that Fyn kinase downregulates NMII activity, thus promoting oligodendrocyte morphological differentiation. © 2012 Wiley Periodicals, Inc.
The head‐mounted microscope
Authors: Chen Ting , Dailey Seth H. , Naze Sawyer A. , Jiang Jack J.
Published: March 2012

Microsurgical equipment has greatly advanced since the inception of the microscope into the operating room. These advancements have allowed for superior surgical precision and better post‐operative results. This study focuses on the use of the Leica HM500 head‐mounted microscope for the operating phonosurgeon. The head‐mounted microscope has an optical zoom from 2× to 9× and provides a working distance from 300mm to 700mm. The headpiece, with its articulated eyepieces, adjusts easily to head shape and circumference, and offers a focus function, which is either automatic or manually controlled. We performed five microlaryngoscopic operations utilizing the head‐mounted microscope with successful results. By creating a more ergonomically favorable operating posture, a surgeon may be able to obtain greater precision and success in phonomicrosurgery. Phonomicrosurgery requires the precise manipulation of long‐handled cantilevered instruments through the narrow bore of a laryngoscope. The head‐mounted microscope shortens the working distance compared with a stand microscope, thereby increasing arm stability, which may improve surgical precision. Also, the head‐mounted design permits flexibility in head position, enabling operator comfort, and delaying musculoskeletal fatigue. A head‐mounted microscope decreases the working distance and provides better ergonomics in laryngoscopic microsurgery. These advances provide the potential to promote precision in phonomicrosurgery. Laryngoscope, 2012
Paradoxical vocal cord motion: Classification and treatment
Authors: Forrest L. Arick , Husein Tiffany , Husein Omar
Published: March 2012

Paradoxical vocal cord motion (PVCM), or vocal cord dysfunction, is a descriptive term for inappropriate adduction of the vocal folds during respiration. The laryngeal mistiming leads to breathing difficulty and is often misdiagnosed as refractory asthma. The etiology of PVCM has been unclear but has long been hypothesized to be psychological. The present thesis is a prospective study of 170 patients older than 18 years being evaluated for PVCM, with 117 of the 170 (68.8%) identified as having PVCM by video laryngoscopy. Laryngeal edema (P = .021) and reflux (P = .026) were increased in patients with PVCM. A flat inspiratory arm of the flow volume loop during spirometry testing was a predictor of PVCM (P = .034). A subgroup of 47 newly diagnosed patients with PVCM underwent psychological analysis. The psychological profiles were elucidated using the Minnesota Multiphasic Personality Inventory and the Life Experiences Survey to evaluate stress. Compared to established normative data, PVCM demonstrated a conversion disorder pattern (P < .01) but not an anxiety disorder or a correlation with stress. A subgroup, 11 of the 47 (23.4%), had normal psychological outcomes, and two of the 47 (4.3%) were identified as malingering. Previous studies have suggested that PVCM is strictly a psychological disorder. It is proposed that PVCM is a descriptive term that is multifactorial and the etiology should direct treatment. A classification scheme divides PVCM into primary, or psychological, and secondary. The secondary form consists of medical disorders divided into irritable larynx syndrome and neurologic disorders. Laryngoscope, 2012
Vinyl‐Type Polynorbornenes with Pendant PCBM: A Novel Acceptor for Organic Solar Cells
Authors: Eo Maengsun , Lee Soohyun , Park Myung Hwan , Lee Min Hyung , Yoo Seunghyup , Do Youngkyu
Published: March 2012

Vinyl addition homo‐ and copolymerization of norbornene monomer (M1) functionalized with a PCBM moiety using a Pd(II) catalyst in combination with a 1‐octene chain transfer agent efficiently produces polynorbornenes with side‐chain PCBM groups. Characterization by NMR spectroscopy and elemental analysis reveals that the copolymers constitute a well‐defined polymer structure with controlled incorporation of M1. Although the homopolymer is insoluble in organic solvents, the copolymers containing 62 mol% (P2) and 50 mol% (P3) of the PCBM moiety are soluble in chlorinated solvents such as o‐dichlorobenzene. The bulk‐heterojunction organic photovoltaic devices fabricated based on the P3HT:P3 blends show that P3 can adequately function as an electron acceptor, leading to a cell with a power conversion efficiency of 1.5%, which is outstanding among the polymeric rivals.
Total scalp reconstruction with bilateral anterolateral thigh flaps
Authors: Kwee Melissa M. , Rozen Warren M. , Ting Jeannette W.C. , Mirkazemi Mansoor , Leong James , Baillieu Charles
Published: March 2012

Large scalp defects can require complicated options for reconstruction, often only achieved with free flaps. In some cases, even a single free flap may not suffice. We review the literature for options in the coverage of all reported large scalp defects, and report a unique case in which total scalp reconstruction was required. In this case, two anterolateral thigh (ALT) flaps were used to resurface a large scalp and defect, covering a total of 743 cm2. The defect occurred after resection and radiotherapy for desmoplastic melanoma, with several failed skin grafts and local flaps and osteoradionecrosis involving both inner and outer tables of the skull. The reconstruction was achieved as a single‐stage reconstruction and involved wide resection of cranium and overlying soft‐tissues and reconstruction with calcium phosphate bone graft substitute, titanium mesh, and two large ALT flaps. The reconstruction was successfully achieved, with minor postoperative complications including tip necrosis of one of the flaps and wound breakdown at one of the donor sites. This is the first reported case of two large ALT flaps for scalp resurfacing and may be the largest reported scalp defect to be completely resurfaced by free flaps. The useof bilateral ALT flaps can be a viable option for the reconstruction of large and/or complicated scalp defects. © 2012 Wiley Periodicals, Inc. Microsurgery, 2012.