bluuebunny/crossref_metadata_2025 huggingface dataset:
When bittersweet turns sour: Adverse effects of nostalgia on habitual worriers
Authors: Verplanken Bas
Published: March 2012

Nostalgic memories can be pleasant, albeit bittersweet, and have been found beneficial for well‐being. This study demonstrated that for individuals who habitually worry, nostalgia may not be such a nourishing experience. Nostalgia was experimentally induced using a visual imagery task and resulted in positive affect. Although this was also the case for participants who habitually worry, these individuals subsequently showed more signs of anxiety and depression than habitual worriers in a control condition. The findings fit within a control theoretical perspective; as habitual worriers' actual chronic state of anxiety contrasts with nostalgic memories of a carefree past, this may instigate further rumination leading to distress. A more present‐oriented time perspective, such as mindfulness, is discussed as being beneficial for habitual worriers. Copyright © 2012 John Wiley & Sons, Ltd.
If time flies, are you more fun? The relative effect of expected exposure duration on the evaluation of social stimuli
Authors: Vliek Michael L. W. , Rotteveel Mark
Published: March 2012

Two studies investigated how expectancy violations of exposure duration affected preference for neutral faces. In two experiments, participants evaluated pictures of neutral faces, ostensibly exposed for the duration of 8 (Experiment 1) or 10 (Experiment 2) seconds each. Exposure duration was manipulated by varying actual exposure time within participants as being either 2 seconds shorter (time “flies”) or 2 seconds longer (time “drags”) than expected. Results confirmed the intuitive hypothesis that neutral faces would be evaluated more positively in situations where time seemed to “fly” compared with situations where time seemed to “drag”. However, comparing affective judgments in both expectancy violation conditions to an expectancy control (i.e., no expectancy violation) condition (Experiment 2) indicated that violations of expected exposure duration actually attenuated affective judgments, such that affective judgments in the absence of temporal discrepancies were most positive. These results suggest that temporal contrasts derived from a violation of duration expectancies may hinder fluent information processing, leading to attenuated affective judgments compared with situations in which no duration expectancies were violated. Copyright © 2012 John Wiley & Sons, Ltd.
Imagined future social pain hurts more now than imagined future physical pain
Authors: Chen Zhansheng , Williams Kipling D.
Published: March 2012

Social pain has been shown to be more easily re‐lived than physical pain. This study further examined whether social pain could be more easily pre‐lived or pre‐experienced than physical pain. Participants were instructed to pre‐live a socially or physically painful event and report their feelings of pain. Consistent with our hypotheses, social pain is easily pre‐lived, but physical pain is not. In addition, individuals with more vivid mental imageries reported higher levels of pain after pre‐living a socially painful event than those with less vivid mental imagery; such a difference was not observed after pre‐living a physically painful event. The discussion was centered on the theoretical and metrological implications of these findings. Copyright © 2012 John Wiley & Sons, Ltd.
Imposex reduction and residual butyltin contamination in southern Brazilian harbors
Authors: Castro Ítalo Braga , Rossato Martina , Fillmann Gilberto
Published: March 2012

The imposex incidence was appraised in South American gastropods, considering the scenario before and after the global ban of tributyltin (TBT). A statistically significant reduction in imposex indexes was observed in Stramonita haemastoma collected in 2006 and 2010 from areas under the influence of four coastal harbors from southern Brazil. This reduction may be because of the effectiveness of the global ban issued by the International Maritime Organization, although the restrictions on TBT-based antifouling paints in Brazil might also have helped. Even so, a residual organotin contamination was still detected in female tissues (levels ranged from 7.6 to 164.9 ng Sn/g for TBT; from <2 to 214.5 ng Sn/g for dibutyltin; from <3.5 to 178.8 ng Sn/g for monobutyltin; and from <1.5 to 53 ng Sn/g for triphenyltin). Thus, although a reduction in imposex and environmental levels of organotins is expected in every ocean worldwide soon after the implementation of national and international restriction regulations, this will depend on the effectiveness of the global TBT ban; the effectiveness of local restrictions on producing, selling, and using TBT-based antifouling paints; and specific characteristics of local sediments, because metabolization rates and sorption/desorption of TBT previously deposited might affect its environmental bioavailability. Therefore, the reduction trend detected in the present study cannot be extrapolated to other Brazilian or South American coastal areas. Environ. Toxicol. Chem. 2012; 31: 947–954. © 2012 SETAC
High tributyltin and imposex levels in the commercial muricid Thais chocolata from two Peruvian harbor areas
Authors: Castro Ítalo Braga , Fillmann Gilberto
Published: March 2012

The first appraisal of butyltin (BT) contamination linked with imposex incidence in Peruvian coastal areas was performed in the present study. Imposex occurrence and BT levels in female bodies were analyzed in the rock snail Thais chocolata distributed along 10 sites in areas under the influence of Callao and Chimbote Harbors. Imposex levels associated to high tributyltin (TBT) concentrations were observed in six of 10 studied sites, and the highest imposex levels were seen in gastropods collected near the harbor terminals. Tributyltin concentrations were the highest reported for gastropod mollusks (up to 662 ng Sn g−1) in recent studies. Although TBT-based antifouling paints have been banned globally (International Maritime Organization, 2008), the combination of high imposex and TBTs level with butyltin degradation index values indicated fresh TBT inputs in these Peruvian coastal areas. Thus, the need to implement local regulatory strategies related to the use of TBT-free antifouling paints is urgent, as is a thorough assessment of the effectiveness of the TBT global ban. Moreover, the wide distribution of T. chocolata combined with its capability to elicit imposex and bioaccumulate BTs renders this a good sentinel species for TBT contamination along the western South American coast. Environ. Toxicol. Chem. 2012; 31: 955–960. © 2012 SETAC
Subclinical hypothyroidism, mood, and cognition in older adults: a review
Authors: Joffe Russell T. , Pearce Elizabeth N. , Hennessey James V. , Ryan Joseph J. , Stern Robert A.
Published: March 2012

Objectives

To perform a critical review of the literature on the mood and cognitive changes associated with subclinical hypothyroidism (SCH), with an emphasis on older adults. To evaluate these data against the Consensus Statement on the management of SCH from the American Association of Clinical Endocrinologists, the American Thyroid Association, and The Endocrine Society.

Method

A comprehensive literature review.

Results

Subclinical hypothyroidism may be associated with an increased risk of mood and cognitive dysfunction, although the strength of this association and the efficacy of replacement hormone therapy require further investigation.

Conclusion

It remains unclear whether SCH leads to significant mood and cognitive impairments in most older patients. More research is required to determine the nature and extent of this association and whether thyroid hormone replacement therapy is appropriate and effective in treating SCH‐associated neurobehavioral impairments. Copyright © 2012 John Wiley & Sons, Ltd.
Transcranial direct current stimulation does neither modulate results of a quantitative sensory testing protocol nor ratings of suprathreshold heat stimuli in healthy volunteers
Authors: Jürgens T.P. , Schulte A. , Klein T. , May A.
Published: March 2012

Background

Transcranial direct current stimulation (tDCS) has been shown to effectively modulate cortical excitability. Several studies have suggested clinical efficacy in pain syndromes such as central neuropathic pain or fibromyalgia. However, little is known regarding tDCS effects on nociception in healthy volunteers.

Methods

In the present study, we examined the effects of anodal, cathodal and sham stimulation of the left primary motor cortex in 17 healthy volunteers on modalities of a comprehensive quantitative sensory testing protocol (including thermal and mechanoreceptive detection and pain thresholds) and on a repetitive heat pain paradigm mimicking clinical pain. The study was conducted in a single‐blind crossover fashion. tDCS was applied at 1 mA for 15 min.

Results

We could not detect any relevant modulation of somatosensory and pain variables in quantitative sensory testing. In addition, no significant alteration of enhanced pain ratings to repetitive noxious heat stimuli (heat hyperalgesia) was found.

Conclusion

As pain processing in chronic pain patients might differ, tDCS could exert its antinociceptive effects depending on the activation level of the nociceptive system.
Tetraspanins stimulate protein synthesis in myeloma cell lines
Authors: Zismanov Victoria , Drucker Liat , Attar‐Schneider Oshrat , Matalon Shelly Tartakover , Pasmanik‐Chor Metsada , Lishner Michael
Published: March 2012

Intensive protein synthesis is a unique and differential trait of multiple myeloma (MM) cells. Previously we showed that tetraspanin (CD81, CD82) overexpression in MM cell lines attenuated Akt/mTOR cascades, activated UPR, and caused autophagic death, suggesting breach of protein homeostasis. Here, we explored the role of protein synthesis in the tetraspanin‐induced MM cell death. Contrary to attenuation of the major metabolic regulator, mTOR we determined elevated steady‐state levels of protein in CD81N1/CD82N1 transfected MM lines (RPMI‐8226, CAG). Elevated levels of immunoglobulins supported increased protein production in RPMI‐8226. Changes in cell morphology consistent with elevated protein synthesis were also determined (cell, nuclei, and nucleoli sizes and ratios). Increased levels of phospho‐rpS6 and decreased levels of phospho‐AMPK were consistent with increased translation but independent of mTOR. Involvement of p38 and its role in tetraspanin induced translation and cell death were demonstrated. Microarray analyses of tetraspanin transfected MM cell lines revealed activation of protein synthesis signaling cascades and signals implicated in ribosome biogenesis (snoRNAs). Finally, we showed tetraspanins elevated protein synthesis was instrumental to MM cells' death. This work explores and demonstrates that excessive protein translation can be detrimental to MM cell lines and therefore may present a therapeutic target. Proteostasis is particularly important in MM because it integrates the high levels of protein production unique to myeloma cells with critically important microenvironmental cues. We suggest that increasing translation may be the path of least resistance in MM and thus may afford a novel platform for strategically designed therapy. J. Cell. Biochem. 113: 2500–2510, 2012. © 2012 Wiley Periodicals, Inc.
Species‐specific biological effects of FGF‐2 in articular cartilage: Implication for distinct roles within the FGF receptor family
Authors: Li Xin , Ellman Michael B. , Kroin Jeffrey S. , Chen Di , Yan Dongyao , Mikecz Katalin , Ranjan KC  , Xiao Guozhi , Stein Gary S. , Kim Su‐Gwan , Cole Brian , van Wijnen Andre J. , Im Hee‐Jeong
Published: March 2012

Existing literature demonstrates that fibroblast growth factor‐2 (FGF‐2) exerts opposing, contradictory biological effects on cartilage homeostasis in different species. In human articular cartilage, FGF‐2 plays a catabolic and anti‐anabolic role in cartilage homeostasis, driving homeostasis toward degeneration and osteoarthritis (OA). In murine joints, however, FGF‐2 has been identified as an anabolic mediator as ablation of the FGF‐2 gene demonstrated increased susceptibility to OA. There have been no previous studies specifically addressing species‐specific differences in FGF‐2‐mediated biological effects. In this study, we provide a mechanistic understanding by which FGF‐2 exerts contradictory biological effects in human versus murine tissues. Using human articular cartilage (ex vivo) and a medial meniscal destabilization (DMM) animal model (in vivo), species‐specific expression patterns of FGFR receptors (FGFRs) are elucidated between human and murine articular cartilage. In the murine OA model followed by intra‐articular injection of FGF‐2, we further correlate FGFR profiles to changes in behavioral pain perception, proteoglycan content in articular cartilage, and production of inflammatory (CD11b) and angiogenic (VEGF) mediators in synovium lining cells. Our results suggest that the fundamental differences in cellular responses between human and murine tissues may be secondary to distinctive expression patterns of FGFRs that eventually determine biological outcomes in the presence of FGF‐2. The complex interplay of FGFRs and the downstream signaling cascades induced by FGF‐2 in human cartilage should add caution to the use of this particular growth factor for biological therapy in the future. J. Cell. Biochem. 113: 2532–2542, 2012. © 2012 Wiley Periodicals, Inc.
Resveratrol chemosensitizes breast cancer cells to melphalan by cell cycle arrest
Authors: Casanova Fabiana , Quarti Julia , da Costa Danielly Cristiny Ferraz , Ramos Caroline Araújo , da Silva Jerson Lima , Fialho Eliane
Published: March 2012

Melphalan (MEL) is a chemotherapeutic agent used in breast cancer therapy; however, MEL's side effects limit its clinical applications. In the last 20 years, resveratrol (RSV), a polyphenol found in grape skins, has been proposed to reduce the risk of cancer development. The aim of this study was to investigate whether RSV would be able to enhance the antitumor effects of MEL in MCF‐7 and MDA‐MB‐231 cells. RSV potentiated the cytotoxic effects of MEL in human breast cancer cells. This finding was related to the ability of RSV to sensitize MCF‐7 cells to MEL‐induced apoptosis. The sensitization by RSV involved the enhancement of p53 levels, the decrease of procaspase 8 and the activation of caspases 7 and 9. Another proposed mechanism for the chemosensitization effect of MCF‐7 cells to MEL by RSV was the cell cycle arrest in the S phase. The treatment with RSV or MEL increased the levels of p‐Chk2. The increase became pronounced in the combined treatments of the compounds. The expression of cyclin A was decreased by treatment with RSV and by the combination of RSV with MEL. While the levels of cyclin dependent kinase 2 (CDK2) remained unchanged by treatments, its active form (Thr160‐phosphorylated CDK2) was decreased by treatment with RSV and by the combination of RSV with MEL. The activity of CDK7, kinase that phosphorylates CDK2 at Thr160, was inhibited by RSV and by the combination of RSV with MEL. These results indicate that RSV could be used as an adjuvant agent during breast cancer therapy with MEL. J. Cell. Biochem. 113: 2586–2596, 2012. © 2012 Wiley Periodicals, Inc.
Synthesis, Structural Characterization and Biological Activity of Cu(II) Compounds Incorporating Pyrazole‐derived Ligand: Effect on Cell Growth in Human Colorectal Carcinoma
Authors: Li Chen‐Yi , Lien Yu‐Ling , Datta Amitabha , Chiu Wan‐Ting , Hsu Chin‐Lin , Huang Jui‐Hsien , Horng Lance , Lin Chia‐Her , Su Chi‐Jung
Published: March 2012

A series of Cu(II) compounds containing neutral multi‐dentate ligand [2,6‐diisopropylphenyl]‐bis[(1‐H‐pyrazol‐1‐yl)methyl]amine (L1) and pyrazole dimethoxethyl ligand [(1‐H‐pyrazol‐1‐yl)methyl]‐bis(2‐methoxyethyl)amine (L2) were synthesized. Reactions of L1 and L2 with copper(II) chloride generate L1CuCl2 (1) and L2CuCl2 (2), respectively. Compounds 1 and 2 have been characterized by elemental analysis and X‐ray single crystal diffractometry. The effects of compounds 1 and 2 on the cell viability of various human cancer cells (including A549, COLO 205, HT‐29, Hep3B, HepG2, Huh7, and PCL5 cells) were investigated. The results indicate that compound 2 has a strong inhibitory effect on cell growth in human colorectal carcinoma cells (COLO 205 cells and HT‐29 cells).
THE SOCIAL SECURITY FUNCTION OF AGRICULTURE IN CHINA
Authors: Wang Xiaobing , Weaver Nick , You Jing
Published: March 2012

On the basis of the Lewis model, this paper addresses the theoretical foundations of the social security function of the agricultural sector and investigates the impact of this function on Chinese development. We argue that the agricultural sector and secure agricultural land holdings are important means, in the absence of comprehensive government provision of social security, in insuring rural residents and rural–urban migrants against risks and uncertainties. Given a large rural population and massive rural–urban migration, secure access to land for both rural and migrant populations in China has helped the economy avoid systemic risk and helped to maintain social stability. Copyright © 2012 John Wiley & Sons, Ltd.
Exploring Directional Consistency in Offending: The Case of Residential Burglary in The Hague
Authors: Daele Stijn Van , Bernasco Wim
Published: March 2012

Many aspects of human behaviour are remarkably stable across times, places and situations. Repetition and predictability also characterises our geographical behaviour. Prior research has confirmed that criminal behaviour is no exception. Offenders tend to recidivate, and recidivists tend to be behaviourally consistent in many aspects, including geographical ones. The present study assesses directional consistency in offending. It reviews the literature on directional consistency. It proposes an improved measure of directional consistency, and empirically uses this measure to explore directional consistency amongst a set of 268 burglars in The Hague. Copyright © 2012 John Wiley & Sons, Ltd.
New insights into the Cu+‐assisted nucleophilic radioiodination of bromopyridine and iodopyridine analogues
Authors: Eersels J. L. H. , Mertens J. , Herscheid J. D. M.
Published: March 2012

The Cu+ method, originally developed for aromatic compounds, has also been applied for radioiodination of pyridine rings. The aim of this paper is a more fundamental approach of the different parameters ruling the Cu+‐assisted radioiodination of the regiomers of pyridine.

A mechanistic model is represented on the basis of the mutual complex‐formation properties of pyridine for Cu+ and Sn++. It is proven that a part of the Cu+ catalyst, required for optimal labelling, is involved in a Halo‐PyrN:Cu+‐complex resulting in a lower labelling yield. In case of 3‐Br‐pyridine and 4‐Br‐pyridine, the Sn++ present in excess versus Cu+ in the general reaction conditions, can displace Cu+ from its pyridine complex rendering it available as catalyst, allowing a successful labelling.

A 2‐Br‐pyridine, with the halogen atom in ortho position of the N atom, is an exception to that rule: the Cu+ ions reversibly bound in the Br‐Pyr‐N:Cu+‐complex are also involved in an intramolecular transfer to the ortho C‐Br bond resulting in an effective molarity exceeding the bulk concentration and a high labelling yield.

Radioiodination of a 2‐halo‐pyridine analogue is preferentially performed in the absence of SnSO4, using only gentisic acid as reducing agent. Copyright © 2012 John Wiley & Sons, Ltd.
Involvement of the L‐arginine/nitric oxide/cyclic guanosine monophosphate pathway in peripheral antinociception induced by N‐palmitoyl‐ethanolamine in rats
Authors: Romero Thiago R.L. , Galdino Giovane S. , Silva Grazielle C. , Resende Lívia C. , Perez Andréa C. , Cortes Steyner F. , Duarte Igor D.G.
Published: March 2012

N‐palmitoyl‐ethanolamine (PEA) is an endogenous substance that was first identified in lipid tissue extracts. It has been classified as a CB2 receptor agonist. Exogenous PEA has the potential to become a valid treatment for neuropathic and inflammatory pain. In spite of the well‐demonstrated antiinflammatory properties of PEA, its involvement in controlling pain pathways remains poorly characterized. The participation of the L‐arginine/nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway in peripheral antinociception has been established by our group to the μ‐, κ‐ or δ‐opioid receptor agonists, nonsteroidal analgesics, α2C‐adrenoceptor agonists, and even nonpharmacological electroacupuncture. The aim of this study was to verify whether the peripheral antinociception effects of PEA involve the activation of this pathway. All drugs were locally administered to the right hind paw of male Wistar rats. The paw pressure test was used, with hyperalgesia induced by intraplantar injection of prostaglandin E2. PEA elicited a local peripheral antinociceptive effect that was antagonized by the nonselective NO synthase (NOS) inhibitor L‐NOARG and the selective neuronal NOS (nNOS) inhibitor L‐NPA. Selective inhibition of endothelial (eNOS) and inducible (iNOS) NOS via L‐NIO and L‐NIL, respectively, was ineffective at blocking the effects of a local PEA injection. In addition, the dosage of nitrite in the homogenized paw, as determined by colorimetric assay, indicated that exogenous PEA is able to induce NO release. The soluble guanylyl cyclase inhibitor ODQ antagonized the PEA effect, whereas the cGMP‐phosphodiesterase inhibitor zaprinast potentiated the antinociceptive effect of low‐dose PEA. This study provides evidence that PEA activates nNOS, thus initiating the NO/cGMP pathway and inducing peripheral antinociceptive effects. © 2012 Wiley Periodicals, Inc.
Estrogen treatment prevents gray matter atrophy in experimental autoimmune encephalomyelitis
Authors: MacKenzie‐Graham Allan J. , Rinek Gilda A. , Avedisian Andrea , Morales Laurie B. , Umeda Elizabeth , Boulat Benoit , Jacobs Russell E. , Toga Arthur W. , Voskuhl Rhonda R.
Published: March 2012

Gray matter atrophy is an important correlate to clinical disability in multiple sclerosis (MS), and many treatment trials include atrophy as an outcome measure. Atrophy has been shown to occur in experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model of MS. The clinical severity of EAE is reduced in estrogen‐reated mice, but it remains unknown whether estrogen treatment can reduce gray matter atrophy in EAE. In this study, mice with EAE were treated with either estrogen receptor (ER)‐α ligand or ER‐β ligand, and diffusion tensor images (DTI) were collected and neuropathology was performed. DTI showed atrophy in the cerebellar gray matter of vehicle‐treated EAE mice compared with healthy controls but not in ER‐α or ER‐β ligand‐treated EAE mice. Neuropathology demonstrated that Purkinje cell numbers were decreased in vehicle‐treated EAE mice, whereas neither ER ligand‐treated EAE groups showed a decrease. This is the first report of a neuroprotective therapy in EAE that unambiguously prevents gray matter atrophy while sparing a major neuronal cell type. Fractional anisotropy (FA) in the cerebellar white matter was decreased in vehicle‐ and ER‐β ligand‐treated but not in ER‐α ligand‐treated EAE mice. Inflammatory cell infiltration was increased in vehicle‐ and ER‐β ligand‐treated but not in ER‐α ligand‐treated EAE mice. Myelin staining was decreased in vehicle‐treated EAE mice and was spared in both ER ligand‐treated groups. This is consistent with decreased FA as a potential biomarker for inflammation rather than myelination or axonal damage in the cerebellum in EAE. © 2012 Wiley Periodicals, Inc.
Nanoprobes for intracellular and single cell surface‐enhanced Raman spectroscopy (SERS)
Authors: Vitol Elina A. , Orynbayeva Zulfiya , Friedman Gary , Gogotsi Yury
Published: March 2012

Surface‐enhanced Raman spectroscopy (SERS) is a promising and powerful label free technique for high resolution analysis of single cells. For intracellular analysis, there is a need for SERS‐active nanoprobes that are minimally invasive to cells, do not affect cell viability, and provide reproducible signals. This work reviews the state‐of‐the‐art tools currently available for intracellular SERS. Various types of SERS probes are considered, including colloidal gold and silver nanoparticles, metallized optical fibers, and tip‐enhanced Raman probes. We also discuss recently developed SERS‐active nanopipettes implemented on the basis of pulled glass microcapillaries. Finally, the critical aspects of selecting an optimal SERS nanoprobe for single‐cell analysis depending on a particular application are summarized. Copyright © 2012 John Wiley & Sons, Ltd.
Near‐UV laser treatment of extrinsic dental enamel stains
Authors: Schoenly J.E. , Seka W. , Featherstone J.D.B. , Rechmann P.
Published: March 2012

Background and Objectives

The selective ablation of extrinsic dental enamel stains using a 400‐nm laser is evaluated at several fluences for completely removing stains with minimal damage to the underlying enamel.

Study Design/Materials and Methods

A frequency‐doubled Ti:sapphire laser (400‐nm wavelength, 60‐nanosecond pulse duration, 10‐Hz repetition rate) was used to treat 10 extracted human teeth with extrinsic enamel staining. Each tooth was irradiated perpendicular to the surface in a back‐and‐forth motion over a 1‐mm length using an ∼300‐µm‐diam 10th‐order super‐Gaussian beam with fluences ranging from 0.8 to 6.4 J/cm2. Laser triangulation determined stain depth and volume removed by measuring 3D surface images before and after irradiation. Scanning electron microscopy evaluated the surface roughness of enamel following stain removal. Fluorescence spectroscopy measured spectra of unbleached and photobleached stains in the spectral range of 600–800 nm.

Results

Extrinsic enamel stains are removed with laser fluences between 0.8 and 6.4 J/cm2. Stains removed on sound enamel leave behind a smooth enamel surface. Stain removal in areas with signs of earlier cariogenic acid attacks resulted in isolated and randomly located laser‐induced, 50‐µm‐diam enamel pits. These pits contain 0.5‐µm diam, smooth craters indicative of heat transfer from the stain to the enamel and subsequent melting and water droplet ejection. Ablation stalling of enamel stains is typically observed at low fluences (<3 J/cm2) and is accompanied by a drastic reduction in porphyrin fluorescence from the Soret band.

Conclusion

Laser ablation of extrinsic enamel stains at 400 nm is observed to be most efficient above 3 J/cm2 with minimal damage to the underlying enamel. Unsound underlying enamel is also observed to be selectively removed after irradiation. Lasers Surg. Med. 44:339–345, 2012. © 2012 Wiley Periodicals, Inc.
New Monodisperse Magnetic Polymer Microspheres Biofunctionalized for Enzyme Catalysis and Bioaffinity Separations
Authors: Horák Daniel , Kučerová Jana , Korecká Lucie , Jankovičová Barbora , Palarčík Jiří , Mikulášek Petr , Bílková Zuzana
Published: March 2012

Magnetic macroporous PGMA and PHEMA microspheres containing carboxyl groups are synthesized by multi‐step swelling and polymerization followed by precipitation of iron oxide inside the pores. The microspheres are characterized by SEM, IR spectroscopy, AAS, and zeta‐potential measurements. Their functional groups enable bioactive ligands of various sizes and chemical structures to couple covalently. The applicability of these monodisperse magnetic microspheres in biospecific catalysis and bioaffinity separation is confirmed by coupling with the enzyme trypsin and huIgG. Trypsin‐modified magnetic PGMA‐COOH and PHEMA‐COOH microspheres are investigated in terms of their enzyme activity, operational and storage stability. The presence of IgG molecules on microspheres is confirmed.

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Photo‐Crosslinked Biodegradable Hydrogels Prepared From Fumaric Acid Monoethyl Ester‐Functionalized Oligomers for Protein Delivery
Authors: Jansen Janine , Mihov George , Feijen Jan , Grijpma Dirk W.
Published: March 2012

Photo‐crosslinkable, fumaric acid monoethyl ester‐functionalized triblock oligomers are synthesized and copolymerized with N‐vinyl‐2‐pyrrolidone to form biodegradable photo‐crosslinked hydrogels. Poly(ethylene glycol) is used as the middle hydrophilic segment and the hydrophobic segments are based on D,L‐lactide, trimethylene carbonate or a mixture of these monomers. Two model proteins, lysozyme and albumin, are incorporated in the hydrogels and their release is studied. The composition of the hydrophobic segments could be used to tune degradation behavior and release rates. Careful optimization of photo‐polymerization conditions is needed to limit conjugation of proteins to the hydrogels and protein denaturation.

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Acenes With a Click
Authors: Waterloo Andreas R. , Kunakom Sylvia , Hampel Frank , Tykwinski Rik R.
Published: March 2012

A protected pentacene precursor is functionalized in the 6‐ and 13‐positions with alkyne groups and subsequently derivatized by a copper‐catalyzed azide–alkyne Huisgen cycloaddition (CuAAC) reaction. Aromatization then gives the desired pentacene derivatives. This method offers an expedient route to a range of bench‐top stable, pentacene, and oligopentacene based chromophores, all derived from a single building block. These new pentacene derivatives are characterized by NMR, IR, and UV‐Vis spectroscopies. X‐ray crystallographic data for two derivatives is used to evaluate the prospect of electronic communication in the solid state via π‐stacking interactions.
Highly Efficient, Red‐Emitting Hyperbranched Polymers Utilizing a Phenyl‐Isoquinoline Iridium Complex as the Core
Authors: Guo Ting , Yu Lei , Zhao Baofeng , Li Yanhu , Tao Yun , Yang Wei , Hou Qiong , Wu Hongbin , Cao Yong
Published: March 2012

Red‐emitting hyperbranched polymers utilizing polyfluorene (PF) and poly(fluorene‐alt‐carbazole) (PFCz) as the branches and the phenyl‐isoquinoline iridium complex [(Piq)2Ir(Pytz)] (where Piq is 1‐phenylisoquinoline and Pytz is 3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole) as the core are synthesized by a Suzuki polycondensation, using the “A2 + A2’ + B3” approach. The HOMO and LUMO levels of the PFCz branch are enhanced compared with those of the PF branches, indicating that the incorporation of the Cz moiety into the fluorene branches can improve hole injection in the polymers, while the potential barrier of electron injection is enlarged. The hyperbranched polymers using fluorene branches exhibit a better device performance. A maximum luminous efficiency of 6.54 cd A−1 (peak external quantum efficiency = 4.88%) at 5.4 V with CIE co‐ordinates of (0.65, 0.34) is obtained from the PF‐PiqIr2 polymer. The device efficiencies from the copolymers show a reduced roll‐off upon an increase of the current density.
Long‐Term Properties of Injection‐Molded Micro‐Parts: Influence of Part Dimensions and Cooling Conditions on Aging Behavior
Authors: Meister Steve , Jungmeier Ariane , Drummer Dietmar
Published: March 2012

A variety of polymer parts used in microsystems technology is produced by injection molding. For dimensioning and design of these products, both the material properties and changes during the life cycle have to be taken into account. The aging behavior of parts with decreasing dimensions or of parts processed under different cooling conditions is discussed in terms of their morphological and mechanical long‐term properties. The results indicate that a decreasing part size leads to higher post‐crystallization and higher thermo‐oxidative degradation. This leads to size‐dependent changes in mechanical properties. Adjusted process conditions by application of thermal low‐conductive mold materials can favor the process‐related properties and thus the long term properties can be improved.

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Microsomal epoxide hydrolase polymorphisms, cigarette smoking, and risk of colorectal cancer: The Fukuoka Colorectal Cancer Study
Authors: Nisa Hoirun , Budhathoki Sanjeev , Morita Makiko , Toyomura Kengo , Nagano Jun , Ohnaka Keizo , Kono Suminori , Ueki Takashi , Tanaka Masao , Kakeji Yoshihiro , Maehara Yoshihiko , Okamura Takeshi , Ikejiri Koji , Futami Kitaroh , Maekawa Takafumi , Yasunami Yohichi , Takenaka Kenji , Ichimiya Hitoshi , Terasaka Reiji
Published: March 2012

Microsomal epoxide hydrolase (EPHX1) plays an important role in the activation and detoxification of polycyclic aromatic hydrocarbons, carcinogens found in cigarette smoke. Polymorphisms in exon 3 (Y113H) and exon 4 (H139R) of the EPHX1 have been associated with enzyme activity. We investigated the risk of colorectal cancer in relation to the EPHX1 Y113H and H139R polymorphisms and assessed effect modifications of cigarette smoking and the other covariates. The interaction between the EPHX1 polymorphisms and selected genetic polymorphisms was also examined. We used data from Fukuoka Colorectal Cancer Study, a community‐based case–control study, including 685 cases and 778 controls. In‐person interviews were conducted to assess lifestyle factors. The EPHX1 Y113H and H139R polymorphisms were determined by the TaqMan assay and the polymerase chain reaction‐restriction fragment length polymorphism, respectively. Neither of the two polymorphisms nor the imputed EPHX1 phenotype was associated with colorectal cancer risk. Cigarette smoking and alcohol intake showed no effect modification on the association with the EPHX1 polymorphisms or the imputed EPHX1 phenotype. Increased risks of colorectal cancer associated with the 113Y allele and imputed EPHX1 phenotype were observed among individuals with high body mass index (BMI; ≥25.0 kg/m2), but not among those with low BMI (<25.0 kg/m2). The risk decreased with an increasing number of the 139R allele in the null genotypes of GSTM1/GSTT1. It is unlikely that the EPHX1 polymorphisms play an important role in colorectal carcinogenesis. The observed interactions of the EPHX1 polymorphisms with BMI and the GSTM1/GSTT1 genotypes warrant further investigation. © 2012 Wiley Periodicals, Inc.
Functional polymorphisms in the insulin‐like binding protein‐3 gene may modulate susceptibility to differentiated thyroid carcinoma in Caucasian Americans
Authors: Xu Li , Mugartegui Liliana , Li Guojun , Sarlis Nicholas J. , Wei Qingyi , Zafereo Mark E. , Sturgis Erich M.
Published: March 2012

The insulin‐like growth factor (IGF) pathway is believed to play a pivotal role in thyroid carcinogenesis. Polymorphisms of IGF‐1 and IGF binding protein‐3 (IGFBP‐3) have been associated with modulation of risk for the emergence of assorted common malignancies, but studies of the influence of such polymorphisms on risk of differentiated thyroid carcinoma (DTC) are lacking. In a case–control study of 173 DTC patients, 101 patients with benign thyroid disease, and 401 controls, an unconditional logistical regression model adjusted for age and sex was applied to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between polymorphisms of IGF‐1 and IGFBP‐3 and DTC risk. IGFBP‐3 rs2132572 GA/AA genotypes were associated with a decreased risk of DTC (adjusted OR = 0.6, 95% CI: 0.4–0.9), particularly multifocal DTC (adjusted OR = 0.3, 95% CI: 0.1–0.7). The association with DTC was more evident in subjects with a first‐degree family history of cancer (adjusted OR = 0.4, 95% CI: 0.2–0.7, Pinteraction = 0.013) and non‐drinkers (adjusted OR = 0.4, 95% CI: 0.2–0.7, Pinteraction = 0.028). A four single nucleotide polymorphism haplotype of IGFBP‐3 was associated with a decreased risk of DTC (adjusted OR = 0.7, 95% CI: 0.5–1.0, P = 0.030). Our study suggests that polymorphic IGFBP‐3 may be involved in susceptibility to DTC. © 2012 Wiley Periodicals, Inc.
How Do Small Businesses Finance Their Growth Opportunities?—The Case of Recovery from the Lost Decade in Japan
Authors: Tsuruta Daisuke
Published: March 2012

Previous studies argue that bank loans are cheaper than trade credit, so less‐constrained firms largely depend on bank loans and use trade credit less, especially in financially developed economies. However, the Japanese evidence does not support this view. First, small businesses with higher credit demand increase trade credit more during the period of the recovery from a severe recession. Second, creditworthy firms also increase trade credit to finance their growth opportunities. Third, firms in unstable industries increase trade credit more. This suggests that suppliers are able to offer credit, unlike banks, as they have a relative advantage in day‐by‐day monitoring. Copyright © 2012 John Wiley & Sons, Ltd.
Existing and Developing Approaches for QSAR Analysis of Mixtures
Authors: Muratov Eugene N. , Varlamova Ekaterina V. , Artemenko Anatoly G. , Polishchuk Pavel G. , Kuz'min Victor E.
Published: March 2012

This review is devoted to the critical analysis of advantages and disadvantages of existing mixture descriptors and their usage in various QSAR/QSPR tasks. We describe good practices for the QSAR modeling of mixtures, data sources for mixtures, a discussion of various mixture descriptors and their application, recommendations about proper external validation specific for mixture QSAR modeling, and future perspectives of this field. The biggest problem in QSAR of mixtures is the lack of reliable data about the mixtures’ properties. Various mixture descriptors are used for the modeling of different endpoints. However, these descriptors have certain disadvantages, such as applicability only to 1 : 1 binary mixtures, and additive nature. The field of QSAR of mixtures is still under development, and existing efforts could be considered as a foundation for future approaches and studies. The usage of non‐additive mixture descriptors, which are sensitive to interaction effects, in combination with best practices of QSAR model development (e.g., thorough data collection and curation, rigorous external validation, etc.) will significantly improve the quality of QSAR studies of mixtures.
Compact ultra‐wideband notch‐band bandpass filters using multiple slotline resonators
Authors: Song Kaijun , Pan Tao , Xue Quan
Published: March 2012

A novel extremely compact ultra‐wideband (UWB) bandpass filter (BPF) with a notch band is presented.The multiple slotline resonators have been applied to construct the UWB BPF and implement the notch band within the UWB passband. Based on the transmission‐line theory, the equivalent‐circuit model of the proposed UWB notch‐band BPF has been developed. The upper cut‐off frequency and passband bandwidth of the UWB BPF, as well as the center frequency of the notched band can be adjusted by tuning the structural parameters. The proposed compact UWB notch‐band BPF using multiple slotline resonators has been designed, simulated, and measured. The measured results agree with the simulated ones closely. The notched band centered at around 5.7 GHz has 10‐dB rejection fractional bandwidths of about 2%. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1132–1135, 2012
Low‐power quadrature voltage‐controlled oscillator formed with two injection‐locked frequency dividers
Authors: Jang Sheng‐Lyang , Chou Li‐Te
Published: March 2012

This article presents a new low‐voltage n‐core quadrature voltage‐controlled oscillator (QVCO), which consists of two low‐voltage n‐core cross‐coupled voltage‐controlled oscillators (VCOs) with two injection MOSFETs in shunt with inductors used for inductive voltage boosting, and the QVCO coupling mechanism is the injection locking.The proposed CMOS QVCO has been implemented with the TSMC 0.18 μm CMOS technology, and the die area is 0.86 × 0.75 mm2. At the supply voltage of 0.7 V, the total power consumption is 0.847 mW. The free‐running frequency of the QVCO is tunable from 4.44 to 5.25 GHz, as the tuning voltage is varied from 0.0 to 0.7 V. The measured phase noise at 1 MHz frequency offset is −118.21 dBc/Hz at the oscillation frequency of 4.615 GHz, and the figure of merit of the proposed QVCO is −192.91 dBc/Hz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1170–1173, 2012
Miniature bandpass filters with stepped‐impedance resonators
Authors: Tsai Lin‐Chuan
Published: March 2012

In this article, a new configuration of higher selectivity bandpass filter using miniature open‐loop stepped‐impedance resonator (SIR) is designed and fabricated. The central frequency of the filter is 2.45 GHz and the bandwidth is 8%. Using miniature open‐loop SIR resonator, we design filter based on cross‐coupling and input and output external quality factor. A single transmission zero is realized by the cross‐coupling in the structures, which can improve the skirt selectivity of the filter. The circuit size of a miniature open‐loop SIR bandpass filter reduces to 50% of the square open‐loop resonator bandpass filter. The results of measurements are in good agreement with the full‐wave simulation results. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1167–1170, 2012
Photonic asynchronous delta‐sigma modulator system for analog‐to‐digital conversion
Authors: Siahmakoun Azad , Constanzo‐Caso Pablo , Reeves Erin
Published: March 2012

A novel photonic asynchronous delta‐sigma modulator (ADSM) has been investigated and demonstrated for the first time in this article. An inverted bistable quantizer is required due to use of a positive feedback in this noninterferometric optical implementation. The principles of the proposed optical first‐order and second‐order ADSM are modeled and analyzed. Two main components of the novel optical ADSM; the leaky integrator and the inverted bistable quantizer have been mathematically analyzed, simulated, and characterized. Finally, a prototype fiber‐optic ADSM is constructed. The prototype operates at MHz frequencies producing four effective‐number‐of‐bits resolution. The reported fiber‐optic ADSM is a very promising for future integration of this system on a photonic chip thus increasing the operation frequency range up to tens of GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1287–1292, 2012
Novel design of compact open‐slot antenna for UWB application with dual band‐notched characteristics
Authors: Sun A.‐F. , Yin Y.‐Z. , Yang Y.
Published: March 2012

In this article, a novel compact UWB antenna with dual band‐notched characteristics is proposed. The original UWB antenna is realized by etching an open‐slot on the ground plane. The 5.2‐ and 5.8‐GHz WLAN rejected bands are achieved by inserting a slot on the ground plane and a slot‐type split ring resonator inside a circular exciting stub on the front side, respectively. The antenna has a compact structure with an area of 16 × 27 mm2. The small size makes it an excellent candidate for UWB operation. Prototype of the antenna are fabricated and tested. The simulated and measured results show that the proposed antenna achieves a wide impedance bandwidth (VSWR < 2) from 2.92 to over 12 GHz, and the dual rejected bands (VSWR > 2) are 4.85–5.37 GHz and 5.68‐5.98 GHz. Radiation patterns and antenna gains are also given in this article. Detailed design steps, parametric studies and experimental results for the antenna are investigated in the following section. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1159–1163, 2012
V‐band high‐isolation CMOS T/R switch fabricated using 90‐nm CMOS technology
Authors: Kuo Chi‐Shin , Kuo Hsin‐Chih , Chuang Huey‐Ru , Chen Chu‐Yu , Huang Tzuen‐Hsi , Huang Guo‐Wei
Published: March 2012

This article presents a V‐band high‐isolation complementary metal‐oxide semiconductor (CMOS) single‐pole double‐throw transmitter/receiver (T/R) switch fabricated with TSMC standard 90‐nm 1P9M CMOS technology. A low insertion loss and high linearity are achieved using the body‐floating technique. In addition, the leakage cancellation technique is used to increase the isolation between the transmitter and receiver ports. The measured results show the insertion loss from the transmitter port to the antenna port is less than 3.5 dB, and the isolation between the transmitter and receiver ports is higher than 28 dB from 57 to 64 GHz. At the center frequency of 60 GHz, the port isolation is higher than 34 dB. The switch isolation has also been measured under the large signal test which is not reported in the previous works. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1118–1123, 2012
A low‐power 3.2–9.7 GHz ultra‐wideband low‐noise amplifier with excellent stop‐band rejection using 0.18‐μm CMOS technology
Authors: Chang Jin‐Fa , Lin Yo‐Sheng
Published: March 2012

A low‐power 3.2–9.7 GHz low‐noise amplifier (LNA) with excellent stop‐band rejection by 0.18‐μm CMOS technology is demonstrated.High stop‐band rejection is achieved using a planar passive band‐pass filter with three finite transmission zeros (in the input terminal of the common‐gate LNA), one of which (ωz1 = 0.9 GHz) is in the low‐frequency stop‐band and the other two (ωz3 and ωz5) are in the high‐frequency stop‐band. In addition, an active notch filter is used in the output terminal of the LNA to introduce another low‐frequency stop‐band transmission zero (ωz2) at 2.4 GHz. The LNA consumes 4.68 mW and achieves S11 of −10 to −39.5 dB, S21 of 9.3 ± 1.5 dB, and an average noise figure (NF) of 6 dB over the 3.2–9.7 GHz band. Moreover, the stop‐band interferers can be effectively attenuated. The measured stop‐band rejection is better than 21.6 dB for frequencies DC ∼2.5 GHz and 11.2–20 GHz. The corresponding stop‐band rejection at 0.9, 1.8, 2.4, 17.6, and 19.5 GHz are 53.3, 26.4, 26.5, 60, and 59.5 dB, respectively. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1253–1261, 2012
Design, development, and performance evaluation of a compact and long‐range passive UHF RFID tag
Authors: Catarinucci L. , Colella R. , Tarricone L.
Published: March 2012

Passive radio frequency identification (RFID) tags can be classified in terms of reading range.Short‐range tags communicate with the reader up to a few centimetres. Medium‐range tags reach almost 5 meters. Long‐range tags work properly up to almost 12 meters. Nevertheless, the longer is the working distance, the larger is the tag size. In this work, a new passive UHF RFID tag has been designed, realized, and tested. Based on the joint use of various design and miniaturization techniques, our device is as compact as a medium‐range tag. The tag prototype has been extensively tested and compared with both a commercial medium‐range tag with similar size and a well‐performing long range tag. For all such tags, measurements of received signal strength indication, working range, tag sensitivity, and differential radar cross section have been carried out and compared. Results are impressive. Despite the compactness of the proposed tag, its performance is appreciably better than the medium‐range tag and even comparable with the tested long range one. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1335–1339, 2012
Facet preparation of polymer based optical wavelength filter using mechanical/chemical treatment technique
Authors: Ibrahim M. H. , Kassim N.M. , Mohammad A. B. , Supa'at A. S. M.
Published: March 2012

A photodefinable polymer of benzocyclobutene (BCB 4024‐40) from Dow Chemical™ has been demonstrated as a waveguiding material in a new structure of optical wavelength filter. The filter structure is based on the combination of restricted interference and general interference schemes of multimode interference technique. The filter is capable in optical wavelength filtering particularly for 1550/1310 nm. Because of the photosensitive nature of the polymer, the chemical wet‐etching fabrication technique needs to be adopted. For the purpose of laser coupling, a new facet polishing technique has been proposed and it is based on the combination of mechanical and chemical polishing. It is shown that the fabricated device works well with improved crosstalk of −15.7 dB (1310 nm) and −21.8 dB (1550 nm). © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1301–1313, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26781