bluuebunny/crossref_metadata_2025 huggingface dataset:
Families of pairs of graphs with a large number of common cards
Authors: Bowler Andrew , Brown Paul , Fenner Trevor
Published: April 2009

The vertex‐deleted subgraph G−v, obtained from the graph G by deleting the vertex v and all edges incident to v, is called a card of G. The deck of G is the multiset of its unlabelled vertex‐deleted subgraphs. The number of common cards of G and H (or between G and H) is the cardinality of the multiset intersection of the decks of G and H. In this article, we present infinite families of pairs of graphs of order n ≥ 4 that have at least \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}\begin{eqnarray*}2\lfloor\frac{1}{3}(n-1)\rfloor\end{eqnarray*}\end{document} common cards; we conjecture that these, along with a small number of other families constructed from them, are the only pairs of graphs having this many common cards, for sufficiently large n. This leads us to propose a new stronger version of the Reconstruction Conjecture. In addition, we present an infinite family of pairs of graphs with the same degree sequence that have \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}\begin{eqnarray*}\frac{2}{3}(n+5-2\sqrt{3n+6})\end{eqnarray*}\end{document} common cards, for appropriate values of n, from which we can construct pairs having slightly fewer common cards for all other values of n≥10. We also present infinite families of pairs of forests and pairs of trees with \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}\begin{eqnarray*}2\lfloor\frac{1}{3}(n-4)\rfloor\end{eqnarray*}\end{document} and \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}\begin{eqnarray*}2\lfloor\frac{1}{3}(n-5)\rfloor\end{eqnarray*}\end{document} common cards, respectively. We then present new families that have the maximum number of common cards when one graph is connected and the other disconnected. Finally, we present a family with a large number of common cards, where one graph is a tree and the other unicyclic, and discuss how many cards are required to determine whether a graph is a tree. © 2009 Wiley Periodicals, Inc. J Graph Theory 63: 146–163, 2010
Finite fields and the 1‐chromatic number of orientable surfaces
Authors: Korzhik Vladimir P.
Published: April 2009

The 1‐chromatic number χ1(Sp) of the orientable surface Sp of genus p is the maximum chromatic number of all graphs which can be drawn on the surface so that each edge is crossed by no more than one other edge. We show that if there exists a finite field of order 4m+1, m≥3, then 8m+2≤χ1(S)≤8m+3, where 8m+3 is Ringel's upper bound on χ1(S). © 2009 Wiley Periodicals, Inc. J Graph Theory 63: 179–184, 2010
Balanced judicious bipartitions of graphs
Authors: Xu Baogang , Yan Juan , Yu Xingxing
Published: April 2009

A bipartition of the vertex set of a graph is called balanced if the sizes of the sets in the bipartition differ by at most one. B. Bollobás and A. D. Scott, Random Struct Alg 21 (2002), 414–430 conjectured that if G is a graph with minimum degree of at least 2 then V(G) admits a balanced bipartition V1, V2 such that for each i, G has at most |E(G)|/3 edges with both ends in Vi. The minimum degree condition is necessary, and a result of B. Bollobás and A. D. Scott, J. Graph Theory 46 (2004), 131–143 shows that this conjecture holds for regular graphs G(i.e., when Δ(G)=δ(G)). We prove this conjecture for graphs G with \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}\begin{eqnarray*}\Delta(G)\le\frac{7}{5}\delta(G)\end{eqnarray*}\end{document}; hence, it holds for graphs ]ensuremathG with \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}\begin{eqnarray*}\delta(G)\ge\frac{5}{7}|V(G)|\end{eqnarray*}\end{document}. © 2009 Wiley Periodicals, Inc. J Graph Theory 63: 210–225, 2010
Towards a comprehensive model of feather regeneration
Authors: Maderson Paul F.A. , Hillenius Willem J. , Hiller Uwe , Dove Carla C.
Published: April 2009

Understanding of the regeneration of feathers, despite a 140 year tradition of study, has remained substantially incomplete. Moreover, accumulated errors and mis‐statements in the literature have confounded the intrinsic difficulties in describing feather regeneration. Lack of allusion to Rudall's (Rudall [1947] Biochem Biophys Acta 1:549–562) seminal X‐ray diffraction study that revealed two distinct keratins, β‐ and α‐, in a mature feather, is one of the several examples where lack of citation long inhibited progress in understanding. This article reviews and reevaluates the available literature and provides a synthetic, comprehensive, morphological model for the regeneration of a generalized, adult contour feather. Particular attention is paid to several features that have previously been largely ignored. Some of these, such as the β‐keratogenic sheath and the α‐keratogenic, supra‐umbilical, pulp caps, are missing from mature, functional feathers sensu stricto because they are lost through preening, but these structures nevertheless play a critical role in development. A new developmental role for a tissue unique to feathers, the medullary pith of the rachis and barb rami, and especially its importance in the genesis of the superior umbilical region (SUR) that forms the transition from the spathe (rachis and vanes) to the calamus, is described. It is postulated that feathers form through an intricate interplay between cyto‐ and histodifferentiative processes, determined by patterning signals that emanate from the dermal core, and a suite of interacting biomechanical forces. Precisely regulated patterns of loss of intercellular adhesivity appear to be the most fundamental aspect of feather morphogenesis and regeneration: rather than a hierarchically branched structure, it appears more appropriate to conceive of feathers as a sheet of mature keratinocytes that is “full of holes. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.
Effects of temperature elevation on neuronal inhibition in hippocampal neurons of immature and mature rats
Authors: Qu Lintao , Leung L. Stan
Published: April 2009

Febrile seizures are the most common seizure type in children, and hyperthermia may contribute to seizure generation during fever. We have previously demonstrated that hyperthermia suppressed γ‐aminobutyric acid (GABA)‐ergic synaptic transmission in CA1 neurons of immature rats. However, whether this suppression is age‐dependent is unknown. Moreover, it is unclear whether hyperthermia has differential effects on neuronal inhibition in CA1 pyramidal cells (PCs) and dentate gyrus granule cells (GCs). In this study, we investigated the effects of hyperthermia on GABAA and GABAB receptor‐mediated inhibitory postsynaptic currents (IPSCs) in CA1 and DG neurons from immature (11–17 days old) and mature (6–8 weeks old) rats using whole‐cell recordings in vitro. In immature rats, hyperthermia decreased the peak amplitude of GABAA receptor‐mediated IPSCs (GABAA IPSCs) in PCs but not in GCs. However, hyperthermia decreased the decay time constant of GABAA IPSCs to a similar extent in both PCs and GCs. In mature rats, hyperthermia decreased the peak amplitude but not the decay time constant of GABAA IPSCs in both PCs and GCs. Hyperthermia decreased charge transfer (area) of the GABAA IPSC of PCs more in immature than in mature rats. In contrast, hyperthermia decreased the GABAB receptor‐mediated IPSCs to the same degree in immature and mature rats, for either CA1 or DG neurons. Because the hippocampus has been found to be involved in hyperthermia‐induced behavioral seizures in immature rats, we suggest that the higher sensitivity of CA1 inhibitory synaptic function to hyperthermia in immature compared with mature rats might partially explain the higher susceptibility for febrile seizures in immature animals. © 2009 Wiley‐Liss, Inc.
Interleukin‐6 increases intracellular Ca2+ concentration and induces catecholamine secretion in rat carotid body glomus cells
Authors: Fan Juan , Zhang Bo , Shu Hai‐Feng , Zhang Xiao‐Yu , Wang Xi , Kuang Fang , Liu Ling , Peng Zheng‐Wu , Wu Rui , Zhou Zhuan , Wang Bai‐Ren
Published: April 2009

Although abundant evidence indicates mutual regulation between the immune and the central nervous systems, how the immune signals are transmitted to the brain is still an unresolved question. In a previous study we found strong expression of proinflammatory cytokine receptors, including interleukin (IL)‐1 receptor I and IL‐6 receptor α in the rat carotid body (CB), a well‐known arterial chemoreceptor that senses a variety of chemostimuli in the arterial blood. We demonstrated that IL‐1 stimulation increases intracellular calcium ([Ca2+]i) in CB glomus cells, releases ATP, and increases the discharge rate in carotid sinus nerve. To explore the effect of IL‐6 on CB, here we examine the effect of IL‐6 on [Ca2+]i and catecholamine (CA) secretion in rat CB glomus cells. Calcium imaging showed that extracellular application of IL‐6 induced a rise in [Ca2+]i in cultured glomus cells. Amperometry showed that local application of IL‐6 evoked CA release from glomus cells. Furthermore, the CA secretory response to IL‐6 was blocked by 200 μM Cd2+, a well‐known Ca2+ channel blocker. Our experiments provide further evidence for the responsiveness of the CB to proinflammatory cytokines and indicate that the CB might play a role in inflammation sensing and transmission of such information to the brain. © 2009 Wiley‐Liss, Inc.
Role of P2Y1 receptor in astroglia‐to‐neuron signaling at dorsal spinal cord
Authors: Zeng Jun‐Wei , Liu Xiao‐Hong , Zhao Yan‐Dong , Xiao Zhi , He Wen‐Juan , Hu Zhi‐An , Ruan Huai‐Zhen
Published: April 2009

Several studies have shown that astrocytes release neurotransmitters into the extracellular space that may then activate receptors on nearby neurons. In the present study, the actions of adenosine 5′‐O‐(2‐thiodiphosphate) (ADPbetaS)‐activated astrocyte conditioned medium (ADPbetaS‐ACM) on cultured dorsal spinal cord neurons were evaluated by using confocal laser scanning microscopy and whole‐cell patch‐clamp recording. ADPbetaS caused astrocytic glutamate efflux (43 μM), which in turn induced inward currents in dorsal horn neurons with short time in culture. The inward currents were abolished by 2‐amino‐5‐phosphonlanoicacid (AP‐5; NMDAR antagonist) plus 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX; non‐NMDAR antagonist) but were unaffected by MRS2179 (selective P2Y1 receptor antagonist). Furthermore, N6‐methyl‐2′‐deoxyadenosine‐3′,5′‐bisphosphate (MRS2179) was used to block glutamate release from astrocytes. As a result, ADPbetaS‐ ACM‐induced inward currents in neurons were significantly blocked. On the other hand, both NMDAR and non‐NMDAR were involved in ADPbetaS‐ACM (concentration was diluted to one‐tenth)‐evoked small [Ca2+]i transients in neurons. Under this condition, the values of glutamate concentrations in the medium are close to values for extracellular glutamate concentrations under physiological conditions. For this reason, it is possible that astrocyte‐derived glutamate is important for distant neuron under physiological conditions at dorsal spinal cord. These observations indicate that astrocytic P2Y1 receptor activation triggered glutamate efflux, which acts on distant neurons to elevate calcium levels or acts on nearby neurons to evoke inward current. Finally, our results support the conclusion that the astrocytic P2Y1 receptor plays an important role in bidirectional communication between astrocytes and neurons. © 2009 Wiley‐Liss, Inc.
Poststroke subgranular and rostral subventricular zone proliferation in a mouse model of neonatal stroke
Authors: Kadam S.D. , Mulholland J.D. , McDonald J.W. , Comi A.M.
Published: April 2009

Stroke in the neonatal brain is an understudied cause of neurologic morbidity. Recently we have characterized a new immature mouse model of stroke utilizing unilateral carotid ligation alone to produce infarcts and acute seizures in postnatal day 12 (P12) CD‐1 mice. In this study, the amount of poststroke neural progenitor proliferation was examined in the subgranular (SGZ) of the dentate gyrus and the subventricular zone (SVZ) 7, 14, and 21days after ischemia (DAI). A single IP injection (50 mg/kg) of bromodeoxyuridine (BrdU) given 2 hr before perfusion fixation labeled newborn cells. Early cell phenotypes were quantified by colabeling with GFAP, nestin, and DCX. Control mice revealed an age‐dependent decrease in neural proliferation, with an ∼50% drop in BrdU‐labeled cell counts at P33 compared with P19 both in the SGZ and in the SVZ. Significant reduction in the amount of neural proliferation in the ipsilateral injured SGZ of ligated mice correlated with both the severity of the stroke‐injury and the acute seizure scores. Similar correlations were not detected contralaterally. Contralateral SGZ neural proliferation was initially lowered at 7 DAI but normalized by 21 DAI. In both injured and control brains, ∼90% of newborn SGZ cells colabeled with nestin, ∼30% colabeled with GFAP, and a few colabeled with DCX. In contrast, poststroke SVZ cell proliferation was enhanced ipsi‐ more than contralaterally at 7 DAI. In the SVZ, the enhanced neural proliferation normalized to control levels by P33. In conclusion, the neural cell proliferation was differentially altered in the SGZ vs. SVZ after neonatal stroke. © 2009 Wiley‐Liss, Inc.
Evaluation of predicted knee‐joint muscle forces during gait using an instrumented knee implant
Authors: Kim Hyung J. , Fernandez Justin W. , Akbarshahi Massoud , Walter Jonathan P. , Fregly Benjamin J. , Pandy Marcus G.
Published: April 2009

Musculoskeletal modeling and optimization theory are often used to determine muscle forces in vivo. However, convincing quantitative evaluation of these predictions has been limited to date. The present study evaluated model predictions of knee muscle forces during walking using in vivo measurements of joint contact loading acquired from an instrumented implant. Joint motion, ground reaction force, and tibial contact force data were recorded simultaneously from a single subject walking at slow, normal, and fast speeds. The body was modeled as an 8‐segment, 21‐degree‐of‐freedom articulated linkage, actuated by 58 muscles. Joint moments obtained from inverse dynamics were decomposed into leg‐muscle forces by solving an optimization problem that minimized the sum of the squares of the muscle activations. The predicted knee muscle forces were input into a 3D knee implant contact model to calculate tibial contact forces. Calculated and measured tibial contact forces were in good agreement for all three walking speeds. The average RMS errors for the medial, lateral, and total contact forces over the entire gait cycle and across all trials were 140 ± 40 N, 115 ± 32 N, and 183 ± 45 N, respectively. Muscle coordination predicted by the model was also consistent with EMG measurements reported for normal walking. The combined experimental and modeling approach used in this study provides a quantitative framework for evaluating model predictions of muscle forces in human movement. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1326–1331, 2009
Quantifying the motion of Kager's fat pad
Authors: Ghazzawi Ahmad , Theobald Peter , Pugh Neil , Byrne Carl , Nokes Len
Published: April 2009

Kager's fat pad is located in Kager's triangle between the Achilles tendon, the superior cortex of the calcaneus, and flexor hallucis longus (FHL) muscle and tendon. Its biomechanical functions are not yet established, but recent studies suggest it performs important biomechanical roles as it is lined by a synovial membrane and its retrocalcaneal protruding wedge can be observed moving into the bursal space during ankle plantarflexion. Such features have prompted hypotheses that the protruding wedge assists in the lubrication of the Achilles tendon subtendinous area, distributes stress at the Achilles enthesis, and removes debris from within the retrocalcaneal bursa. This study examined the influence of FHL activity and Achilles tendon load on the protruding wedge sliding distance, using both dynamic ultrasound imaging and surface electromyogram. Intervolunteer results showed sliding distance was independent of FHL activity. This study has shown the protruding wedge to slide on average 60% further into the retrocalcaneal bursa when comparing the Achilles tendon loaded versus unloaded, consistently reaching the distal extremity. Sliding distance was dependant on a change in the Achilles tendon insertion angle. Our results support a number of hypothesized biomechanical functions of the protruding wedge including: lubrication of the subtendinous region; reduction of pressure change within the Achilles tendon enthesis organ; and removal of debris from within the retrocalcaneal bursa. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1457–1460, 2009
Effects of vancomycin, daptomycin, fosfomycin, tigecycline, and ceftriaxone on Staphylococcus epidermidis biofilms
Authors: Hajdu Stefan , Lassnigg Andrea , Graninger Wolfgang , Hirschl Alexander M. , Presterl Elisabeth
Published: April 2009

Infection of medical implanted material is associated with considerable morbidity and costs. In the following work, we investigated the effects of vancomycin, daptomycin, fosfomycin, tigecycline, and ceftriaxone on biofilms formed by Staphylococcus epidermidis isolates causative for implant infection and catheter‐associated bacteremia. Biofilms were studied using the static microtiter plate model and incubated with the antibiotics increasing the concentration from 1× to 128× the minimal inhibitory concentration (MIC) of the respective isolate tested. To quantify the reduction of the biomass, the optical density ratio (ODr) of stained biofilms and the number of growing bacteria were determined. Incubation of the staphylococcal biofilms with the antibiotics decreased the biofilm ODr (at baseline = 1) for ceftriaxone (0.83 ± 0.48) but minimally only for fosfomycin (0.96 ± 0.64), daptomycin (1.05 ± 0.59), tigecycline (1.18 ± 0.66), and vancomycin (0.98 ± 0.44) at exceedingly high concentrations of 128 × MIC. The significant reduction of the bacterial growth was not achieved for all antibiotics, not even at the highest concentrations tested. Using higher doses of the antibiotics may be of some value in the treatment of biofilm‐associated infections, although effects are seen only at clinically unachievable doses. However, to eradicate the staphylococcal biofilm, additional measures like debridement and/or removal of the implant are needed. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1361–1365, 2009
Visible Raman spectroscopy for the discrimination of olive oils from different vegetable oils and the detection of adulteration
Authors: El‐Abassy R. M. , Donfack P. , Materny A.
Published: April 2009

We have investigated the potential of Raman spectroscopy with excitation in the visible spectral range (VIS Raman) as a tool for the classification of different vegetable oils and the quantification of adulteration of virgin olive oil as an example. For the classification, principal component analysis (PCA) was applied, where 96% of the spectral variation was characterized by the first two components. A significant similarity between sunflower oil and extra‐virgin olive oil was found using this approach. Therefore, sunflower oil is a potential candidate for adulteration in most commercially available olive oils. Beside the classification of the different vegetable oils, we have successfully applied Raman spectroscopy in combination with partial least‐squares (PLS) regression analysis for very fast monitoring of adulteration of extra‐virgin olive oil with sunflower oil. Different mixtures of extra‐virgin olive oil with three different sunflower oil types were prepared between 5 and 100% (v/v) in 5% increments of sunflower oil. While in the present context the adulteration usually refers to the addition of reasonable amounts of the adulterant (given the similarity with the basic product), we show that the technique proposed can also be used for trace analysis of the adulterant. Without using techniques like surface‐enhanced Raman scattering (SERS), a quantitative detection limit down to 500 ppm (0.05%) could be achieved, a limit irrelevant for adulteration in commercial terms but significant for trace analysis. The qualitative detection limit even was at considerably lower concentration values. Based on PCA, a clear discrimination between pure extra‐virgin olive oil and olive oil adulterated with sunflower oil was achieved. The adulterant content was successfully determined using PLS regression with a high correlation coefficient and small root mean‐square error for both prediction and validation. Copyright © 2009 John Wiley & Sons, Ltd.
Study of the vibrational spectra of (CH3)3GeCl from experimental and DFT calculations
Authors: Roldán María Lorena , Brandán Silvia Antonia , Navarro Amparo , Ben Altabef Aída
Published: April 2009

New infrared (for gas and liquid phase) and Raman (for liquid) spectra were measured for the chlorotrimethylgermane to obtain a complete assignment of its fundamental modes. The measurement of the low‐temperature infrared spectrum together with the application of Fourier self‐deconvolution to the Raman spectra resolves the CH vibrational modes into their components. The Rauhut and Pulay scaled quantum mechanical (SQM) force field methodology and the wavenumber‐linear scaling (WLS) method were used to predict the vibrational spectra as a guide to the assignment of the fundamental bands. A quantum mechanical analysis was carried out to obtain the harmonic force field. Copyright © 2009 John Wiley & Sons, Ltd.
Simultaneous determination of 103 pesticide residues in tea samples by LC‐MS/MS
Authors: Huang Zhiqiang , Zhang Ying , Wang Libing , Ding Li , Wang Meilin , Yan Hongfei , Li Yongjun , Zhu Shaohua
Published: April 2009

A simple and sensitive method was developed and validated for the simultaneous determination of 103 pesticide residues in tea by LC‐MS/MS. For the analysis of the pesticide with polarity, thermal lability or low volatility, this LC‐MS/MS method has an advantage over GC. In this work, residual pesticides were extracted from the tea sample with ACN and then purified using Carb‐NH2 SPE cartridges. Using the multiple reaction monitoring mode, the pesticides were quantified and identified by the most abundant and characteristic fragment ions. The recoveries obtained for each pesticide ranged between 65 and 114% at three spiked concentration levels. The intra‐day precisions were lower than 19.6%. Good linear relationships were observed with the correlation coefficients r2 >0.996 for all analytes. The established method was successfully applied to the determination of pesticide residues in real tea samples.
LC‐MS of novel narcoepileptics and related substances
Authors: Nageswara Rao Ramisetti , Shinde Dhananjay D. , Ramesh Venna , Srinivas Ragampeta
Published: April 2009

Modafinil, adrafinil and their related substances were synthesized and analyzed by RP‐LC with ESI‐MS/MS. The ionization mode, polarity, cone voltage, and chromatographic conditions were evaluated. The optimum LC‐MS conditions to obtain fragment ions indispensable for identification of the structures were described. The bulk drugs purity of modafinil and adrafinil was evaluated on Kromasil C18 column with ACN/0.02 M ammonium acetate as mobile phase in gradient elution mode at 30°C. The method was found to be suitable not only for monitoring the reactions during the process development but also for quality assurance of modafinil and adrafinil.
SFE kinetics of bioactive compounds from Helianthus annuus L.
Authors: Casas Lourdes , Mantell Casimiro , Rodríguez Miguel , Torres Ascensión , Macías Francisco A. , Martínez de la Ossa Enrique J.
Published: April 2009

The kinetics of the supercritical fluid extraction of bioactive compounds from sunflower using CO2 as solvent were studied in order to establish an efficient method for this extraction. The influence of time of extraction at different solvent flow rates was investigated. The extraction pressure and temperature were optimized in previous studies and these values used were 400 bar and 50°C. The extraction yields and the bioactivity levels of the extracts were also analysed. The results indicate that the most appropriate extraction time is between 120 and 180 min depending on the solvent flow and the pretreatment of the sample. The dried sample extracted at 40 g/min, the congealed sample extracted at the same flow and 180 min, and the dried sample extracted at 25 g/min for 120 min showed the best activity profiles. The extractions were carried out in a pilot plant with an extraction vessel with a capacity of 2 L.
Quantitation of imidazo[1,2‐a]quinoxaline derivatives in human and rat plasma using LC/ESI‐MS
Authors: Khier Sonia , Moarbess Georges , Deleuze‐Masquefa Carine , Solassol Isabelle , Margout Delphine , Pinguet Frédéric , Bonnet Pierre‐Antoine , Bressolle Françoise M. M.
Published: April 2009

Since several years, our group developed quinoxalinic compounds. Among the synthesized compounds, in the imidazo[1,2‐a]quinoxaline series, EAPB0203 has shown interesting activities both on melanoma and lymphoma. The structure of EAPB0203 has been modulated and a new compound, EAPB0503, exhibits an in vitro cytotoxic activity on melanoma cancer cell line 7–9 times higher than EAPB0203. We validated an LC/ESI‐MS method to simultaneously quantify EAPB0503 and its metabolite EAPB0603 in human and rat plasma. Chromatography was performed on a C8 Zorbax eclipse XDB column with a mobile phase consisting of acetronitrile and formate buffer gradient elution. LC‐MS data were acquired in SIM mode at m/z 305, 291, and 303 for EAPB0503, EAPB0603, and the internal standard, respectively. The drug/internal standard peak area ratios were linked via quadratic relationships to concentrations (low range: 5–300 μg/L, high range: 100–1000 μg/L). The method is precise (precision, ⪇14%) and accurate (recovery, 92–113%). Mean extraction efficiencies, >72% for each analyte, were obtained. The lower LOQs were 5 μg/L. This highly specific and sensitive method was successfully used to investigate plasma concentrations of EAPB0503 and EAPB0603 in a pharmacokinetic study carried out in rat and would also be useful in clinical trials at a later stage.
Removal of endocrine‐disrupting compounds from water using macroporous molecularly imprinted cryogels in a moving‐bed reactor
Authors: Le Noir Mathieu , Plieva Fatima M. , Mattiasson Bo
Published: April 2009

Highly efficient removal of endocrine‐disrupting compounds (EDCs) such as 17β‐estradiol (E2), 4‐nonylphenol (NP) and atrazine from water was achieved using a novel macroporous adsorption medium. The medium consisted of a macroporous poly(vinyl alcohol) (PVA) cryogel with molecularly imprinted polymer (MIP) particles embedded in it. The MIP was prepared using E2, NP and atrazine as templates. The macroporous composite molecularly imprinted cryogels were formed inside the open‐ended protective shells, known as Kaldnes carriers. These adsorbents (defined as Macroporous Gel Particles, MGPs) were evaluated on the removal of E2, NP and atrazine from water using different column configurations, namely column filled with the MGPs (packed‐bed column) and in moving‐bed reactors (defined here as moving‐bed MGPs reactor). Complete binding (> 99%) of E2 from a spiked aqueous solution (1 mg/L) was achieved using E2‐MIP/MGPs in a moving‐bed MGPs reactor at the retention time in the reactor of 4 min, while only 77% was bound to the nonimprinted medium (NIP/MGPs). Similar results were also obtained for the adsorption medium imprinted with atrazine. All contaminants studied (E2, atrazine and NP) were effectively removed from water at low (environmentally relevant) concentrations by the respective adsorption medium.
Instrumental planar chromatographic method for determination of carbamazepine in human serum
Authors: Mennickent Sigrid , Fierro Ricardo , Vega Mario , de Diego Marta , Godoy C. Gloria
Published: April 2009

An instrumental planar chromatographic (HPTLC) method for quantification of carbamazepine in human serum was developed using liquid‐liquid extraction with dichloromethane, fluorescence activation with perchloric acid 60%/ethanol/water (1:1:1, v/v) and fluorescence detection. Planar chromatographic separation was performed on precoated silica gel F254 HPTLC plates using a mixture of ethyl acetate/toluene/methanol/acetic acid glacial (5:4:0.5:0.5, v/v) as mobile phase. Densitometric detection was done at 366 nm. The method was validated for linearity, precision and accuracy. Linear calibration curves in the range of 3 and 20 ng/μL showed correlation coefficient of 0.998. The intra‐assay and inter‐assay precision, expressed as the RSD, were in the range of 0.41–1.24% (n = 3) and 2.17–3.17% (n = 9), respectively. The LOD was 0.19 ng, and the LOQ was 0.57 ng. Accuracy, calculated as percentage recovery, was between 98.98 and 101.96%, with a RSD not higher than 1.52%. The method was selective for the active principle tested. In conclusion, the method is useful for quantitative determination of carbamazepine in human serum.
Simultaneous extraction of tocotrienols and tocopherols from cereals using pressurized liquid extraction prior to LC determination
Authors: Milagros Delgado‐Zamarreño M. , Bustamante‐Rangel Myriam , Sierra‐Manzano Sergio , Verdugo‐Jara Marcela , Carabias‐Martínez Rita
Published: April 2009

Tocopherols and tocotrienols have been simultaneously determined in food samples using a rapid and simple analytical method including pressurized liquid extraction (PLE) and LC with electrochemical detection. Separation was carried out on a Phenomenex Synergi 4 μm Hydro‐RP 80A column, using a solution of 2.5 mM acetic acid/sodium acetate in methanol/water (99:1, v/v) as mobile phase at a flow rate of 1.0 mL/min. Column temperature was maintained at 30°C. Detection was performed by coulometric detection at 500 mV except for (β+γ)‐tocotrienol, in wheat and rye samples, which was at +350 mV. A palm oil containing a relatively large amount of γ‐tocotrienol and lower concentrations of α‐ and δ‐tocotrienols and α‐ and γ‐tocopherols was used to provide reference retention times for the tocotrienols. Analyte quantification was performed using the external standard method. The calibration equations of tocopherols were used to quantify both tocopherols and their corresponding tocotrienols. The extraction recoveries obtained using the optimized PLE conditions were in the 80–114% range, with RSDs lower than 15%. The method was successfully applied to the determination of tocotrienols and tocopherols in cereal (wheat, rye, barley, maize and oat) and palm oil samples.
Development and validation of an HPLC method for the determination of seven penicillin antibiotics in veterinary drugs and bovine blood plasma
Authors: Samanidou Victoria F. , Giannakis Dimitrios E. , Papadaki Antonia
Published: April 2009

Herein a quantitative method for the determination of seven penicillins in bovine plasma and veterinary drugs has been developed. Amoxicillin (AMO), ampicillin (AMP), penicillin G (PENG), penicillin V (PENV), oxacillin (OXA), cloxacillin (CLO) and dicloxacillin (DICLO) were separated on a Perfectsil ODS‐2 (250×4 mm, 5 μm) column, using gradient elution, with a mobile phase of 0.1% v/v TFA and ACN–methanol (90:10 v/v). PDA detection was used at 240 nm. Penicillins were isolated from bovine plasma by SPE on Lichrolut RP‐18 cartridges with mean recoveries from 85.7 to 113.5%. Colchicine (3 ng/μL) was used as an internal standard. The developed method was validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity. Repeatability (n = 5) and between‐day precision (n = 5) revealed RSD < 12%. The detection limits in the bovine plasma were estimated as 18 ng for AMO and AMP, 25 for PENG, PENV and OXA, 3 ng for CLO and 12 ng for DICLO. Spiked plasma samples were stable for 1 wk, except for AMP and CLO, which were stable for 3 wk and OXA for 4 wk. AMO, PENG and PENV were stable for two freeze–thaw cycles, OXA, CLO and DICLO for four, while AMP only for one.
Kinetics of acid degradation of proton pump inhibitors in the presence of a thiol
Authors: Al‐Matar Ali Kh. , El‐Eswed Bassam , Tutunji Maha F.
Published: April 2009

An in vitro investigation of the kinetics of the complex system of acid‐catalyzed conversions and subsequent reactions of proton pump inhibitors (PPIs; omeprazole, lansoprazole and pantoprazole) was carried out using differential pulse polarography at the static mercury drop electrode. Reactions were investigated in the presence of 2‐mercaptoethanol, in solutions buffered to pH values ranging from 2.0 to 5.0. The first‐order reaction network was proposed for all conversions. The rate of degradation of PPIs and subsequent reactions with 2‐mercaptoethanol were found to follow the following general order: lansoprazole > omeprazole > pantoprazole. The rate of conversion of PPIs into sulfenic acid was found to be directly dependent on the basicity of benzimidazole nitrogen of PPIs, which determines the electrophilic reactivity of the adjacent carbon (C2). The rate of conversion of the sulfenic acid of PPIs into the disulfide (the inhibition reaction) was found to be dependent on the electrophilicity of the sulfur atom of the sulfenic acid. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 498–506, 2009
Rate constants of the gas‐phase reactions of OH radicals with trans‐2‐hexenal, trans‐2‐octenal, and trans‐2‐nonenal
Authors: Gao Tingting , Andino Jean M. , Rivera Carlos C. , Márquez Misaela Francisco
Published: April 2009

The rate constants of the gas‐phase reaction of OH radicals with trans‐2‐hexenal, trans‐2‐octenal, and trans‐2‐nonenal were determined at 298 ± 2 K and atmospheric pressure using the relative rate technique. Two reference compounds were selected for each rate constant determination. The relative rates of OH + trans‐2‐hexenal versus OH + 2‐methyl‐2‐butene and β‐pinene were 0.452 ± 0.054 and 0.530 ± 0.036, respectively. These results yielded an average rate constant for OH + trans‐2‐hexenal of (39.3 ± 1.7) × 10−12 cm3 molecule−1 s−1. The relative rates of OH+trans‐2‐octenal versus the OH reaction with butanal and β‐pinene were 1.65 ± 0.08 and 0.527 ± 0.032, yielding an average rate constant for OH + trans‐2‐octenal of (40.5 ± 2.5) × 10−12 cm3 molecule−1 s−1. The relative rates of OH+trans‐2‐nonenal versus OH+ butanal and OH + trans‐2‐hexenal were 1.77 ± 0.08 and 1.09 ± 0.06, resulting in an average rate constant for OH + trans‐2‐nonenal of (43.5 ± 3.0) × 10−12 cm3 molecule−1 s−1. In all cases, the errors represent 2σ (95% confidential level) and the calculated rate constants do not include the error associated with the rate constant of the OH reaction with the reference compounds. The rate constants for the hydroxyl radical reactions of a series of trans‐2‐aldehydes were compared with the values estimated using the structure activity relationship. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 483–489, 2009
Kinetics of gas‐phase reactions of CH3OCH2CF3, CH3OCH3, CH3OCH2CH3, CH3CH2OCH2CH3, and CHF2CF2OCH2CF3 with NO3 radicals at 298 K
Authors: Chen L. , Uchimaru T. , Kutsuna S. , Tokuhashi K. , Sekiya A. , Okamoto H.
Published: April 2009

Rate constants for the gas‐phase reactions of CH3OCH2CF3 (k1), CH3OCH3 (k2), CH3OCH2CH3 (k3), and CH3CH2OCH2CH3 (k4) with NO3 radicals were determined by means of a relative rate method at 298 K. NO3 radicals were prepared by thermal decomposition of N2O5 in a 700–750 Torr N2O5/NO2/NO3/air gas mixture in a 1‐m3 temperature‐controlled chamber. The measured rate constants at 298 K were k1 = (5.3 ± 0.9) × 10−18, k2 = (1.07 ± 0.10) × 10−16, k3 = (7.81 ± 0.36) × 10−16, and k4 = (2.80 ± 0.10) × 10−15 cm3 molecule−1 s−1. Potential energy surfaces for the NO3 radical reactions were computationally explored, and the rate constants of k1–k5 were calculated according to the transition state theory. The calculated values of rate constants k1–k4 were in reasonable agreement with the experimentally determined values. The calculated value of k5 was compared with the estimate (k5 < 5.3 × 10−21 cm3 molecule−1 s−1) derived from the correlation between the rate constants for reactions with NO3 radicals (k1–k4) and the corresponding rate constants for reactions with OH radicals. We estimated the tropospheric lifetimes of CH3OCH2CF3 and CHF2CF2OCH2CF3 to be 240 and >2.4 × 105 years, respectively, with respect to reaction with NO3 radicals. The tropospheric lifetimes of these compounds are much shorter with respect to the OH reaction. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 490–497, 2009
Harmonic scalpel in the treatment of Zenker's diverticulum
Authors: Fama Anthony F. , Moore Eric J. , Kasperbauer Jan L.
Published: April 2009

Objectives/Hypothesis:

To describe the transoral treatment of Zenker's diverticulum with a harmonic scalpel and review the initial outcomes of patients treated with this technique.

Study Design and Methods:

Retrospective study of 25 patients with symptomatic Zenker's diverticula who were treated endoscopically with the harmonic scalpel (Ethicon Endo‐Surgery, Inc, Cincinnati, OH). Electronic medical records were reviewed. Extracted data included outpatient clinic notes, operative reports, hospital summaries, and follow‐up visits.

Results:

All identified patients (N = 25) were treated successfully and safely with the harmonic scalpel. All patients were observed overnight, and 21 (84%) were dismissed the day after surgery. One patient with a history of cardiac disease had a non–ST‐elevation myocardial infarction, one patient had aspiration pneumonia, and two patients had chest pain (both stayed for complete evaluations with negative findings). One patient had subcutaneous emphysema. No patients had hemorrhage, infection, mediastinitis, or death in the postoperative period. The average length of follow‐up was 10.3 months. One patient had a recurrent diverticulum that was treated with an open surgical technique.

Conclusions:

Various treatment options are available for Zenker's diverticulum. There has been a trend toward less invasive techniques, and the harmonic scalpel is one useful treatment option. This review demonstrates that the harmonic scalpel is a safe and effective alternative. Longer follow‐up time is needed to assess long‐term success and incidence of recurrence with this new technique. Laryngoscope, 2009
A single-center experience of 500 liver transplants using the modified piggyback technique by Belghiti
Authors: Mehrabi Arianeb , Mood Zhoobin A. , Fonouni Hamidreza , Kashfi Arash , Hillebrand Norbert , Müller Sascha A. , Encke Jens , Büchler Markus W. , Schmidt Jan
Published: April 2009

Over the past 4 decades, the surgical techniques of liver transplantation (LTx) have permanently evolved and been modified. Among these, the modified piggyback (MPB) technique by Belghiti offers specific advantages. The objective of this study was to present our single-center experience with the MPB technique in 500 cases. Recipients' perioperative data were prospectively collected and evaluated. Postoperative and specific complications, stay in the intensive and intermediate care unit, and the mortality rate with cause of death were analyzed. Most recipients were classified as Child C (49.1%). For the patients who underwent LTx for the first time, alcoholic (23.9%) and viral (22.2%) cirrhosis and hepatocellular carcinoma (15.1%) were the prevalent indications. The overall median warm ischemia time, anastomosis duration, and operative time were 45, 108, and 320 minutes, respectively. The median intraoperative blood loss was 1500 mL. A venovenous bypass was never needed to maintain hemodynamic stability. Only in a few cases was temporary inferior vena cava clamping necessary. Most prominent surgical complications were hemorrhage, hematoma, and wound dehiscence. Renal failure occurred in 6.2% of patients. The overall median stay in the intensive and intermediate care unit was 14 days. The mortality rates within 30 and 90 days were 6.3% and 13.3%, respectively. No technique-related death occurred. The MPB technique by Belghiti is a feasible and simple LTx technique. The caval flow is preserved during the anhepatic phase, and this minimizes the need for venovenous bypass or portocaval shunt. This technique requires only 1 caval anastomosis, which is easy to perform with a short anhepatic phase. To minimize the risk of outflow obstruction, attention should be paid by doing a wide cavocavostomy cranially to the donor inferior vena cava in a door-lock manner. This technique can be applied in almost all patients undergoing LTx for the first time and liver retransplantation as well.
Safety and effectiveness of ezetimibe in liver transplant recipients with hypercholesterolemia
Authors: Almutairi Fawaz , Peterson Theresa C. , Molinari Michele , Walsh Mark J. , Alwayn Ian , Peltekian Kevork M.
Published: April 2009

Hypercholesterolemia is a common problem among transplant recipients. Despite package-insert warnings about the potential side effects of the use of statins in patients with chronic liver disease, they are often prescribed for liver transplant recipients. Unlike statins, ezetimibe acts through inhibition of enterohepatic recirculation of lipids. We report the effectiveness and safety of ezetimibe among liver transplant recipients because this has been evaluated previously only in kidney and heart transplant patients. A consecutive cohort of 25 liver graft recipients with serum low-density lipoprotein (LDL) levels > 100 mg/dL (2.5 mmol/L) after a mean (±standard deviation) of 55 ± 21 months following liver transplantation received ezetimibe (10 mg orally every day) for at least 6 months. Serum lipid profiles, liver and renal function tests, and dosages and blood levels of the immunosuppression drugs at baseline, 3 months, and 6 months were prospectively collected. The overall mean age was 58 ± 12 years, and 56% were males. Statin therapy and fibrates were already being used in 32% and 20% of recipients for elevated LDL and/or triglycerides, respectively. The immunosuppression regimen included cyclosporine in 48% of subjects, tacrolimus in 32%, sirolimus in 48%, and mycophenolate mofetil in 44%; only 12% were on oral prednisone with a maximum daily dose of 5 mg. After ezetimibe was started, an 18% reduction in LDL values was observed [at baseline, 147 ± 35 mg/dL (3.8 ± 0.9 mmol/L), and at 6 months, 120 ± 31 mg/dL (3.1 ± 0.8 mmol/L); P = 0.010]. After 6 months, an additional 32% achieved the target LDL level of <100 mg/dL. None of the remaining variables, including immunosuppression drug levels, varied significantly during ezetimibe therapy. None of the subjects required adjustments in their pharmacological dosages. One discontinued ezetimibe 3 months later because of cost, 2 subjects had minimal nausea, 1 subject had myalgias without a rise in creatine phosphokinase, and 1 subject had a transient elevation (3-5 times) in liver enzymes from baseline with increases in the total and indirect bilirubin levels. In conclusion, among liver transplant recipients, hypercholesterolemia can be effectively treated with ezetimibe with few side effects and no interaction with immunosuppressive regimens.
Successful liver transplantation for Budd-Chiari syndrome in a patient with paroxysmal nocturnal hemoglobinuria treated with the anti-complement antibody eculizumab
Authors: Singer Andrew L. , Locke Jamye E. , Stewart Zoe A. , Lonze Bonnie E. , Hamilton James P. , Scudiere Jennifer R. , Anders Robert A. , Rother Russell P. , Brodsky Robert A. , Cameron Andrew M.
Published: April 2009

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hemolytic anemia caused by somatic mutations in the phosphatidylinositol glycan-complementation class A gene and the resulting absence of a key complement regulatory protein, CD59. Affected red blood cells in patients with PNH undergo intravascular complement-mediated lysis with resulting anemia, hemoglobinuria, and venous thromboses. Hepatic venous outflow thrombosis [Budd-Chiari syndrome (BCS)] is especially common in PNH patients and often fatal. The few case reports of outcomes in patients undergoing liver transplant for BCS secondary to PNH detail instances of recurrent BCS as well as early thrombotic portal vein occlusion and hepatic artery thrombosis requiring retransplantation. PNH is therefore generally considered a contraindication to liver transplantation. Here we present the first report of a patient with PNH and BCS undergoing successful liver transplantation while receiving eculizumab, a humanized monoclonal antibody that blocks the activation of the terminal complement at C5.
Risk factors for developing de novo autoimmune hepatitis associated with anti–glutathione S-transferase T1 antibodies after liver transplantation
Authors: Salcedo Magdalena , Rodríguez-Mahou Margarita , Rodríguez-Sainz Carmen , Rincón Diego , Alvarez Emilio , Vicario Jose Luis , Catalina Maria-Vega , Matilla Ana , Ripoll Cristina , Clemente Gerardo , Bañares Rafael
Published: April 2009

De novo autoimmune hepatitis (de novo AIH) is a rare form of graft dysfunction that develops after liver transplantation (LT) in patients transplanted for conditions other than autoimmune disorders. Although characterized by biochemical, serological, and histological features of AIH, de novo AIH is sometimes associated with atypical serum autoantibodies, many of which are directed against glutathione S-transferase T1 (anti-GSTT1). GSTT1 donor/recipient genotype mismatch has been suggested as a necessary condition for the appearance of autoantibodies and de novo AIH. However, clinically evident disease is not observed in all patients with anti-GSTT1 antibodies. We examined the incidence of de novo AIH and its conditioning (risk) factors in patients with anti-GSTT1 antibodies. Anti-GSTT1 autoantibodies were detected in 29 of 419 [6.9%; 95% confidence interval (CI), 4.9–9.8] consecutive adult LT recipients with donor/recipient GSTT1 mismatch. Twenty of 27 assessable patients (74%) developed de novo AIH after a median follow-up of 26 months (95% CI, 19.2–32.8). The probability of de novo AIH was 11%, 44%, and 60% 12, 24, and 36 months after LT, respectively. No relationship emerged between de novo AIH and recipient gender, donor and recipient age, rejection episodes, immunosuppressive regime, allelic GSTT1 expression, human leukocyte antigen distribution, or cytomegalovirus infection. Multivariate analysis identified male donor [hazard ratio (HR), 3.3; 95% CI, 1.18–9.26; P = 0.018], nonalcoholic etiology (HR, 4.67; 95% CI, 1.64–13.3; P = 0.002), and high anti-GSTT1 titer (HR, 2.98; 95% CI, 1.04–8.57; P = 0.035) as independent predictors of de novo AIH. Most patients with anti-GSTT1 antibodies and donor/recipient GSTT1 mismatch developed clinically evident de novo AIH after LT. The risk of developing the disease was increased by male donor gender, nonalcoholic etiology of original liver disease, and a high anti-GSTT1 titer.
Use of ionic liquid for the enzyme‐catalyzed polymerization of phenols
Authors: Zaragoza‐Gasca Pedro , Villamizar‐Gálvez Omar J. , García‐Arrazola Roeb , Gimeno Miquel , Bárzana Eduardo
Published: April 2009

Ionic liquid and buffer mixture media are first reported in the peroxidase‐catalyzed polymerization of phenol. Yield of 100% with molecular weights of 7000 KDa, as assessed by size‐exclusion chromatography (SEC), were attained using 1‐butyl‐3‐methylimidazolium tetrafluoroborate–buffer mixtures with added hydrogen peroxide. The simplicity of the process and the low vapor pressure of the solvent media allow an eco‐friendly alternative to the general synthesis of polyphenolic‐type biopolymers. Evidence for the consequent polyphenol (PPO) was obtained from solid‐state 13C cross‐polarization magic angle spinning (CP‐MAS) NMR spectroscopy and FT‐IR. Copyright © 2009 John Wiley & Sons, Ltd.