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DNA double-strand breaks (DSBs) are highly toxic lesions that can cause genomic instability and can be repaired by non-homologous end-joining (NHEJ) and homologous recombination (HR) pathways. Despite extensive studies about DSB repair pathways, the roles of each pathway during meiotic maturation in oocytes are not well understood. Here we show that oocytes selectively utilize NHEJ and HR to repair DSBs during meiotic maturation. Inhibition of NHEJ impaired the meiotic maturation of oocytes with DNA damage by activating the spindle assembly checkpoint (SAC) with a concomitant increase in metaphase I (MI) arrest and DNA damage levels. In contrast, oocytes with DNA damage bypassed SAC-mediated MI arrest despite the presence of fragmented DNA when HR was inhibited. Notably, this bypass of SAC arrest by HR inhibition was associated with a loss of centromere integrity and subsequent impairment of chromosome architecture. Our results demonstrate that, while NHEJ is critical for the meiotic maturation of oocytes with DNA damage, HR is essential to maintain centromere integrity against DNA damage during meiotic maturation, revealing distinct roles of NHEJ and HR during meiotic maturation in mouse oocytes.

A prolonged time span between ovulation and fertilization can cause postovulatory aging of oocytes, which impairs oocyte quality and subsequent embryo development. Telomere attrition has long been considered as the primary hallmark of aging or the cause of age-associated diseases. However, the status of telomere and its regulation during postovulatory oocyte aging are poorly understood. Here we found that oocytes experience telomere shortening during postovulatory aging, although they have the capacity to maintain telomere length. However, translationally controlled tumor protein (TCTP) overexpression could reverse age-associated telomere shortening by upregulating telomerase activity in mouse oocytes. Telomere length in mature oocytes gradually decreased with postovulatory aging, which was associated with a marked reduction in TRF1 expression, decreased telomerase activity, and decreased homologous combination (HR)-based alternative lengthening of telomeres (ALT) with a concomitant increase in oxidative stress. Surprisingly, however, overexpression of TCTP led to a remarkable increase in telomere length during postovulatory aging. Notably, neither TRF1 nor BRCA1 level was altered by TCTP overexpression. Moreover, TCTP-mediated telomere lengthening was not blocked by HR inhibition. In striking contrast, telomerase activity, as well as TERT and TERC levels, increased after TCTP overexpression. Importantly, unlike the chromosome-wide distribution of endogenous TCTP, overexpressed TCTP was ectopically localized at telomeres, implying that TCTP overexpression is required to increase telomerase activity. Collectively, our results demonstrate that TCTP prevents telomere attrition during postovulatory aging by upregulating telomerase activity in mouse oocytes.

BACKGROUND We aimed to investigate the treatment response and associated factors for loss of control in children with chronic spontaneous urticaria (CSU). METHODS A total of 240 CSU patients (aged 0-17 years) were enrolled in a single-center study in Korea from May 2014 to May 2019. We retrospectively reviewed the medical records and compared the duration of treatment and step of medications using the urticaria control test (UCT, range 0-16 points). Serum total immunoglobulin levels, eosinophil count, allergic sensitization, autologous serum skin test, antinuclear antibody, thyroid function test, erythrocyte sedimentation rate, and C-reactive protein were measured. The patients were divided into well-controlled (sustained UCT ≥12), partly controlled (fluctuating UCT around 12), and poorly controlled (sustained UCT

In mammals, the early embryo travels down the oviduct to the uterus and prepares for implantation. The unique features of preimplantation development include compaction followed by blastocyst formation. This first cell lineage specification involves various proteins including cell polarity regulators, kinases, and transcription factors. In this study, a novel gene named predicted gene 11545 (Gm11545) expressed predominantly in mouse early embryos was identified and characterized at the transcript, protein, cellular, and functional levels. The Gm11545 protein localized to both cytoplasmic and membrane regions of preimplantation embryos. Remarkably, knockdown of Gm11545 led to arrest of mouse embryos at the morula stage and consequent impairment of blastocyst formation. Expression patterns of the key transcription factors critical for early lineage specification, octamer-binding transcription factor 4 and caudal type homeobox 2, were affected by Gm11545 depletion. Based on the collective findings, we propose that the novel protein identified in this study, Gm11545, is implicated in cell proliferation and cell lineage specification critical for blastocyst formation.-Kim, J., Kim, J., Jeong, J., Hong, S. H., Kim, D., Choi, S., Choi, I., Oh, J. S., Cho, C. Identification of a novel embryo-prevalent gene, Gm11545, involved in preimplantation embryogenesis in mice.

Study on recrystallization of deformed metal is important for practical industrial applications. Most of studies about recrystallization behavior focused on the migration of the high-angle grain boundaries, resulting in lack of information of the kinetics of the low angle grain boundary migration. In this study, we focused on the migration of the low angle grain boundaries during recrystallization process. Pure nickel deformed by shot peening which induced plastic deformation at the surface was investigated. The surface of the specimen was prepared by mechanical polishing using diamond slurry and colloidal silica down to 0.02 μm. Sequential heat treatment under a moderate annealing temperature facilitates to observe the migration of low angle grain boundaries. The threshold energy for low angle boundary migration during recrystallization as a function of misorientation angle was evaluated using scanning electron microscopy techniques. A combination of electron channeling contrast imaging and electron backscatter diffraction was used to measure the average dislocation density and a quantitative estimation of the stored energy near the boundary. It was observed that the migration of the low angle grain boundaries during recrystallization was strongly affected by both the stored energy of the deformed matrix and the misorientation angle of the boundary. Through the combination of electron channeling contrast imaging and electron backscatter diffraction, the threshold stored energy for the migration of the low angle grain boundaries was estimated as a function of the boundary misorientation.

The quantity of the crystalline phases present in a nanomaterial is an important parameter that governs the correlation between its properties and microstructure. However, quantification of crystallinity in nanoscale-level applications by conventional methods (Raman spectroscopy and X-ray diffraction) is difficult because of the spatial limitations of sampling. Therefore, we propose a technique that involves using energy-filtered electron diffraction in transmission electron microscopy which offers improved spatial resolution. The degree of crystallinity (DOC) was calculated by separating the crystalline and amorphous intensities from the total intensity histogram acquired by the azimuthal averaging of the zero-loss filtered signals from electron diffraction. In order to validate the method, it was demonstrated that the DOC calculated by zero-loss filtered electron diffraction was consistent with the DOC measured by the area ratio using an amorphous silicon on crystalline silicon standard sample. In addition, the results obtained from zero-loss filtered and conventional electron diffractions were compared. The zero-loss filtered electron diffraction successfully provided the reliable results of the crystallinity quantification. In contrast, the DOC measured using conventional electron diffraction yielded extremely variable results. Therefore, our results provide a crystallinity quantification technique that can extract quantitative information about crystallinity of nanoscale devices by using zero-loss filtered electron diffraction with better reliability than conventional electron diffraction. RESEARCH HIGHLIGHTS: The degree of crystallinity can be measured by separating the crystalline and amorphous intensities from the total intensity histogram acquired by the azimuthal averaging of the zero-loss filtered signals from selected area electron diffraction.

Dynamic changes in the actin network are crucial for the cortical migration of spindles and establishment of polarity, to ensure asymmetric division during meiotic maturation. In this study, filamin A (FLNA) was found to be an essential actin regulator that controlled spindle migration and asymmetric division during oocyte meiosis. FLNA was localized in the cytoplasm and enriched at the cortex and near the chromosomes. Knockdown of FLNA impaired meiotic asymmetric division and spindle migration with a decrease in the amount of cytoplasmic actin mesh and cortical actin levels. Moreover, FLNA knockdown reduced the phosphorylation of cofilin and Rho kinase (ROCK) near the spindle. Similar phenotypes, such as decreased filament actin levels, impaired spindle migration and polar body extrusion, were observed when active cofilin (S3A) was overexpressed or ROCK was inhibited. Notably, we found that FLNA and ROCK interacted directly in mouse oocytes. Taken together, our results show that FLNA plays crucial roles in asymmetric division during meiotic maturation by regulating ROCK-cofilin-mediated actin reorganization.-Wang, H., Guo J., Lin, Z., Namgoong, S., Oh, J. S., Kim, N.-H. Filamin A is required for spindle migration and asymmetric division in mouse oocytes.

Mammalian oocytes remain arrested at the first prophase of meiosis in ovarian follicles for an extended period. During this protracted arrest, oocytes are remarkably susceptible to the accumulation of DNA damage. Melatonin (N-acetyl-5-methoxytryptamine), a hormone secreted by the pineal gland, has diverse effects on various physiological processes. However, the effect of melatonin on DNA damage response in mammalian oocytes has not been explored. Here, we showed that melatonin protected mouse oocytes from DNA damage induced by double-strand breaks (DSBs) during prophase arrest and subsequently improved oocyte quality. We found that DNA damage during prophase arrest impaired subsequent meiotic maturation and deteriorated oocyte quality, increasing chromosome fragmentation, spindle abnormality, mitochondrial aggregation, and oxidative stress. However, melatonin treatment during DNA damage accumulation at prophase improved meiotic maturation and relieved the quality decline of oocytes. In addition, melatonin inhibited the accumulation of DNA damage during prophase arrest by reducing the γ-H2AX levels. Although activated ATM levels were decreased by melatonin treatment, the effect of melatonin on DNA damage response was not a direct consequence of ATM inhibition. Instead, melatonin enhanced DNA repair via nonhomologous end-joining (NHEJ) pathway. Interestingly, these actions of melatonin on DNA damage response are receptor-independent in mouse oocytes. Therefore, our results demonstrated that melatonin protects oocytes from DNA damage during prophase arrest by enhancing DNA repair via NHEJ and subsequently prevents the deterioration of oocyte quality during meiotic maturation.

Age-related hearing loss (ARHL) is a major neurodegenerative disorder and the leading cause of communication deficit in the elderly population, which remains largely untreated. The development of ARHL is a multifactorial event that includes both intrinsic and extrinsic factors. Recent studies suggest that NAD+ /NADH ratio may play a critical role in cellular senescence by regulating sirtuins, PARP-1, and PGC-1α. Nonetheless, the beneficial effect of direct modulation of cellular NAD+ levels on aging and age-related diseases has not been studied, and the underlying mechanisms remain obscure. Herein, we investigated the effect of β-lapachone (β-lap), a known plant-derived metabolite that modulates cellular NAD+ by conversion of NADH to NAD+ via the enzymatic action of NADH: quinone oxidoreductase 1 (NQO1) on ARHL in C57BL/6 mice. We elucidated that the reduction of cellular NAD+ during the aging process was an important contributor for ARHL; it facilitated oxidative stress and pro-inflammatory responses in the cochlear tissue through regulating sirtuins that alter various signaling pathways, such as NF-κB, p53, and IDH2. However, augmentation of NAD+ by β-lap effectively prevented ARHL and accompanying deleterious effects through reducing inflammation and oxidative stress, sustaining mitochondrial function, and promoting mitochondrial biogenesis in rodents. These results suggest that direct regulation of cellular NAD+ levels by pharmacological agents may be a tangible therapeutic option for treating various age-related diseases, including ARHL.

Battery separators are supposed to be electrical insulators to prevent internal short-circuit failure between electrodes as well as having porous channels to allow ion transport. Here, as a multifunctional membrane strategy to dispel this stereotypical belief about battery separators, a new class of Janus-faced, dual (ion/electron)-conductive/chemically active battery separators (denoted as “Janus separators”) based on a heterolayered nanofiber mat architecture is demonstrated. The Janus separator, which is fabricated through in-series, concurrent electrospraying/electrospinning processes, consists of an ion-conductive/metal ion-chelating support layer (a mat of densely packed, thiol-functionalized silica particles spatially besieged by polyvinylpyrrolidone/polyacrylonitrile nanofibers) and a dual-conductive top layer (a thin mat of polyetherimide nanofibers wrapped with multi-walled carbon nanotubes). The support layer acts as a chemical trap that can capture heavy metal ions dissolved in liquid electrolytes and the top layer serves as an upper current collector for cathodes to boost the redox reaction kinetics. Notably, the unusual porous microstructure of the top layer is theoretically elucidated using molecular dynamics simulation. Benefiting from such material/structural uniqueness, the Janus separator enables significant improvements in fast-rate charge/discharge reactions (even for high-mass loading cathodes) and in the high-temperature cycling performance, which lie far beyond those achievable with conventional polyethylene separators.

It is well established that aging is associated with increased susceptibility to infectious diseases. Fusobacterium nucleatum is a well-known bacterial species that plays a central bridging role between early and late colonizers in the human oral cavity. Further, the ability of F. nucleatum to invade gingival fibroblasts (GFs) is critical to the development of periodontal diseases. However, the mechanisms underlying the age-related infection of GFs by F. nucleatum remain unknown. We used young (fourth passage) and senescent (22nd passage) GFs to investigate the mechanisms of F. nucleatum infection in aged GFs and first observed increased invasion of F. nucleatum in senescent GFs. We also found that the co-localization of caveolin-1 (Cav-1), a protein marker of aging, with F. nucleatum and the knockdown of Cav-1 in GFs reduced F. nucleatum invasion. Additionally, F. nucleatum infection triggered the production of reactive oxygen species (ROS) through activation of NADPH oxidase in GFs, but senescent GFs exhibited significantly lower levels of NADPH oxidase activity and ROS production compared with young GFs in both the uninfected and infected conditions. Also, senescent GFs exhibited a decline in proinflammatory cytokine production and extracellular signal regulated kinase (ERK) phosphorylation following F. nucleatum infection. Interestingly, the knockdown of Cav-1 in senescent GFs increased NADPH oxidase activity and caused the upregulation of interleukin-6 and interleukin-8 and the phosphorylation of ERK. Collectively, the increased expression of Cav-1 might play a critical role in F. nucleatum invasion and could hinder the host response in senescent GFs.

Objectives/Hypothesis To enhance understanding of spontaneous laryngeal muscle reinnervation following severe recurrent laryngeal nerve injury by testing the hypotheses that 1) nerve fibers responsible for thyroarytenoid muscle reinnervation can originate from multiple sources and 2) superior laryngeal nerve is a source of reinnervation. Study Design Prospective, controlled, animal model. Methods A combination of retrograde neuronal labeling techniques, immunohistochemistry, electromyography, and sequential observations of vocal fold mobility were employed in rat model of chronic recurrent laryngeal nerve injury. The current study details an initial set of experiments in sham surgical and denervated group animals and a subsequent set of experiments in a denervated group. Results At 3 months after recurrent laryngeal nerve resection, retrograde brainstem neuronal labeling identified cells in the characteristic superior laryngeal nerve cell body location as well as cells in a novel caudal location. Regrowth of neuron fibers across the site of previous recurrent laryngeal nerve resection was seen in 87% of examined animals in the denervated group. Electromyographic data support innervation by both the superior and recurrent laryngeal nerves following chronic recurrent laryngeal nerve injury. Conclusions Following chronic recurrent laryngeal nerve injury in the rat, laryngeal innervation is demonstrated through the superior laryngeal nerve from cells both within and outside of the normal cluster of cells that supply the superior laryngeal nerve. The recurrent laryngeal nerve regenerates across a surgically created gap, but functional significance of regenerated nerve fibers is unclear. Laryngoscope, 123:2216–2227, 2013

We report the characteristics of GaN-based light-emitting diode (LED) grown on a circular convex patterned sapphire substrate (CCPSS) and conventional LEDs on a non-patterned sapphire substrate (PSS) by metal-organic chemical vapor deposition. A near field scanning optical microscope (NSOM) and micro Raman spectroscopy were employed to investigate the crystalline properties. In NSOM image and spectra of LED on CCPSS, an improved crystalline quality with emission fluctuation feature on the trench region was obtained. However, stress relaxation in this trench region was not achieved due to the presence of voids, indicating a stress concentration at the coalescence region. Compared to conventional LED on non-PSS, increased internal quantum efficiency (IQE) (41.8%) and reduced leakage currents (40 nA at -10 V) were observed in the LED fabricated on CCPSS. The light output power of the LED on CCPSS was approximately two times higher than that of a conventional LED. This enhancement of output power is contributed to increase of IQE and the effective suppression of leakage current by reduction of dislocation density, as well as enhanced light scattering via the circular convex facets. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Organo-montmorillonite/NBR nanocomposites were prepared by a melt intercalation process. The characteristics of NBR nanocomposites were characterized by oscillating-disk rheometer, water-vapour transmission and transmission electron microscopy (TEM). Changes in cure characteristics resulting from changes in clay content and the addition of silane coupling agent were investigated. The study confirmed that organo-montmorillonite/NBR nanocomposites cure characteristics, viz minimum torque, maximum torque, scorch time and curing time, change according to the change in clay content and the addition of silane coupling agent. Of the water-vapour transport properties, the clay content and silane content are the dominating factors in determining the individual water-vapour permeability of these NBR nanocomposites. TEM analysis provided clear evidence for the homogeneous dispersion of clay in the NBR matrix without regard to increases in clay content. Copyright © 2004 Society of Chemical Industry

Nanocomposites of organophilic montmorillonite (C18-MMT), nitrile–butadiene rubber (NBR), and a coupling agent were produced during a melt compounding process at room temperature. During the process, it was clearly observed that organo-MMT particles were exfoliated into nanoscale layers of approximately 1–30 nm thickness, in addition to their original 40 μm thickness. These MMT layers were uniformly dispersed in the NBR matrix. The effects of a coupling agent such as 3-(mercaptopropyl)trimethoxy silane in C18-MMT/NBR nanocomposites were studied. The C18-MMT/NBR nanocomposites in the presence of the coupling agent were identified and characterized by X-ray diffraction, transmission electron microscopy, a universal testing machine, thermogravimetric analysis, and IR spectroscopy. It was observed that an additional silane coupling agent, 3-(mercaptopropyl)trimethoxy silane, enhanced the chemical interaction and was accompanied by the formation of SiOSi coupling bonds between C18-MMT and the coupling agent and SiC coupling bonds between NBR and the coupling agent. This work resulted in improved properties of organo-MMT/NBR nanocomposites because of the nanoscale effects and strong interaction of the coupling bonds between NBR and organo-MMT. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2633–2640, 2003

The effect of clay modification on organo-montmorillonite/NBR nanocomposites has been studied. Organo-montmorillonite/NBR nanocomposites were prepared through a melt intercalation process. NBR nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic mechanical thermal analysis (DMTA) and a universal testing machine (UTM). XRD showed that the basal spacing in the clay increased, which means that the NBR matrix was intercalated in the clay layer galleries. On TEM images, organo-montmorillonite (MMT) particles were clearly observed, having been exfoliated into nanoscale layers of about 10–20 nm thickness from their original 40 µm particle size. These layers were uniformly dispersed in the NBR matrix. The DMTA test showed that for these nanocomposites the plateau modulus and glass transition temperature (Tg) increased with respect to the corresponding values of pure NBR (without clay). UTM test showed that the nanocomposites had superior mechanical properties, ie strength and modulus. These improved properties are due to the nanoscale effects and strong interactions between the NBR matrix and the clay interface. Copyright © 2003 Society of Chemical Industry

Organo-montmorillonite/nitrile rubber (NBR) nanocomposites were prepared by a melt intercalation process. The characteristics of NBR nanocomposites were determined by an oscillating disk rheometer and transmission electron microscopy. The cure characteristics were investigated according to the change in clay content and clay types. This study confirmed that organo-montmorillonite/NBR nanocomposites have various cure characteristics, namely minimum torque, maximum torque, scorch time and curing time, according to the change in clay content and clay types. In particular, as the chain length of the modifier used for the treatment of Na+-MMT following vulcanization increases, scorch time and optimum curing time are reduced. This is because, as the chain length of the modifier increases, organo-MMT is distributed more equally during the formation of the nanocomposites. As swelling increases, the chain length of the clay modifier expands and then constitutes a better barrier. Copyright © 2003 Society of Chemical Industry

Imperatorin, a biologically active furanocoumarin from the roots of Angelica dahurica (Umbelliferae), was found to induce apoptosis in human promyelocytic leukaemia, HL-60 cells. DNA fragmentation assay, morphology-based evaluation, and flow cytometric analysis demonstrated that imperatorin at micromolar concentrations was able to trigger apoptosis of HL-60 cells. Neither necrosis nor differentiation was observed at cytotoxic micromolar concentrations of imperatorin. Further studies showed that the cytochrome c/caspase-9 pathway was responsible for imperatorin-induced apoptosis; i.e., mitochondrial membrane was depolarized, Bcl-2 was down-regulated, cytochrome c was released from mitochondria, caspase-9 and caspase-3 were activated, and poly(ADP-ribose) polymerase was cleaved. Furthermore, imperatorin-induced apoptosis was significantly blocked by Z-VAD-FMK (a broad spectrum caspase inhibitor), Z-LEHD-FMK (a caspase-9 inhibitor) and Ac-DMQD-CHO (a caspase-3 inhibitor), but not by Z-IEDT-FMK (a caspase-8 inhibitor).

In the present study we have investigated whether butein could induce apoptosis in human leukaemic HL-60 cells. The treatment of HL-60 cells with butein induced apoptotic cell death as determined by morphological and biochemical changes. Apoptotic DNA fragments in the butein-treated HL-60 cells were increased gradually as determined by flow cytometric analysis. The caspase-3 activity was increased during butein-induced apoptosis. However, caspase-3 inhibitor abrogated the butein-induced DNA fragmentation. Furthermore, the treatment of HL-60 cells with butein decreased the expression of Bcl-2 protein, but increased the expression of Bax protein. These results suggest that butein-induced apoptosis is mediated through the activation of caspase-3 and it is associated with changed expression of Bcl-2 and Bax proteins.

Interactive display of complex scenes is a challenging problem in computer graphics. Such current approaches as z-buffer, level of detail and visibility culling have not fully used the temporal coherence between consecutive frames. When the viewing condition is fixed, the color and depth values of static polygons can be obtained from the result of the previous frame and only the remaining dynamic polygons require rendering. We present a method that enhances the speed of the conventional z-buffer algorithm by exploiting the above temporal coherence. This algorithm is simple to combine with existing graphics hardware that supports the conventional z-buffer algorithm. It can manipulate any scene suitable for the z-buffer algorithm without preprocessing or human intervention. The rendering time is proportional to the number of dynamic polygons in each frame. Experimental results show that our method is faster than the conventional z-buffer algorithm and the performance enhancement becomes higher as the fraction of static polygons increases. Copyright © 2001 John Wiley & Sons, Ltd.

We report the fabrication of InGaN/GaN multi quantum well (MQW) microdisk arrays on Si(111) substrates. InGaN/GaN MQWs were grown on highly tensile-strained GaN films on Si(111) substrate by metalorganic chemical vapor deposition. Microdisk resonators were fabricated using a combination of optical lithography, a dry GaN-etching process, and Si undercut etching by acid chemical solution. The evidence of whispering-gallery modes in optically pumped microdisk cavities have been observed by photoluminescence. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Transesterification reactions between polyarylate (PAr) and a copolyester (PETG) have been investigated by proton nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry. Blends of PAr and PETG were prepared by melt mixing and solution-casting with weight fractions of PAr in the blends varying from 0.90 to 0.10. The PETG is a copolyester containing ethylene-1,4-cyclohexylene dimethylene terephthalate. From the thermal analysis of the PAr/PETG melt blends, a single glass transition temperature is observed, which indicates a miscibility between the PAr and PETG. The benzene insoluble fraction of the PAr/PETG (50/50) melt blends and solution-cast blends were characterized using NMR and FTIR. The results of NMR and FTIR support the conclusion that transesterification reactions between the PAr and PETG occurred under the melt blending conditions applied.

Blends of poly(ether imide) (PEI) and bisphenol-A polycarbonate (PC) have been investigated by differential scanning calorimetry, dynamic mechanical thermal analyzer, scanning electron microscopy, and transmission electron microscopy. Three different molecular weights of polycarbonate have been used in the PEI-PC blends. Blends were prepared by screw extrusion and solution casting with weight fractions of PEI in the blends varying from 0.90 to 0.10. From the measured glass transition temperature (T g ), the maximum decrease of T g (PEI) is observed for 0.9 weight fraction PEI in the PEI-PC blends. In the study of the morphology, the size of minor component domains (about 0.1 to 0.3 μm) in the 90/10 PEI-PC blend is small compared to the size of minor component domains (about 0.2 to 2.0 μm) in the 10/90 PEI-PC blend. This morphological behavior is attributed mainly to the difference of viscosity ratio between the dispersed phase and continuous phase. No considerable differences in the thermal behavior and morphologies have been observed among the blends of PEI and PC having different molecular weights.

A heterogeneous Lewis acid catalytic system has been developed by incorporating gadolinium triflate on to poly[styrene- co -(1-((4-vinylphenyl)methyl)-3-methylimidazolium) tetrafluoroborate] ( 1 -Gd(OTf) 3 ), and the catalytic activity of this system has been examined for Michael additions of amines and thiols to α,β-unsaturated esters and acrylonitrile. The reactions proceed in moderate to excellent yields in the presence of catalytic system 1 -Gd(OTf) 3 . The catalytic system could be efficiently recycled and reused.

ProblemThe ability to reliably restore physiologic movement to a paralyzed vocal fold is not yet in hand. Muscle-nerve-muscle (M-N-M) neurotization is a process whereby axons sprouting from within an innervated muscle are directed toward a denervated muscle via a neural conduit. Given the paired laryngeal musculature, M-N-M neurotization holds promise for restoring physiologic vocal fold movement in cases of unilateral paralysis. This study is aimed at exploring the effectiveness of M-N-M neurotization in a rat model.MethodsTwelve Sprague-Dawley rats were divided equally into Control and M-N-M groups. The left recurrent laryngeal nerve was transected in both groups, and in the M-N-M group a nerve graft was interposed between the innervated right thyroarytenoid (TA) muscle and the denervated left TA muscle via bilateral laryngeal windows. Vocal fold mobility was serially documented pre- and post-operatively by video-assisted endoscopy. The rats will be sacrificed at 6 weeks and immunohistochemistry used to...

We report a new application of the Suzuki-Miyaura reaction whereas two bifunctional reactants, 3,8-dibromo-1,10-phenanthroline and 3,5-diethynylheptyloxylbenzene (9), yield 3,8-bis (3-ethynyl-5-heptyloxyphenylethynyl)-1,10-phenanthroline (2) efficiently (74% yield) without polymerization. This was achieved by reacting a stoichiometric amount of 9 and (Me3Si)2NLi to obtain quantitatively the monoacetylide anion of 9 (10). The latter was activated with B-methoxy-9-BBN and reacted in analogy to the alkynyl copper complex of a Sonogashira route. However, in the Sonogashira reaction, the alkynyl copper complex is present in small equilibrium concentrations and polymerization takes place even when reagents are mixed slowly. Actually the Sonogashira route gave no desired product 2, as the latter polymerizes easily via homo-coupling in the presence of air and Cu(I). Sonogashira coupling involves the palladium(0) catalyzed reaction of terminal alkynes.