bluuebunny/crossref_metadata_2025 huggingface dataset:
Generalized analytical solution for advection-dispersion equation in finite spatial domain with arbitrary time-dependent inlet boundary condition
Authors: Chen J.-S. , Liu C.-W.
Published: April 2011

Abstract. This study presents a generalized analytical solution for one-dimensional solute transport in finite spatial domain subject to arbitrary time-dependent inlet boundary condition. The governing equation includes terms accounting for advection, hydrodynamic dispersion, linear equilibrium sorption and first order decay processes. The generalized analytical solution is derived by using the Laplace transform with respect to time and the generalized integral transform technique with respect to the spatial coordinate. Several special cases are presented and compared to illustrate the robustness of the derived generalized analytical solution. Result shows an excellent agreement. The analytical solutions of the special cases derived in this study have practical applications. Moreover, the derived generalized solution which consists an integral representation is evaluated by the numerical integration to extend its usage. The developed generalized solution offers a convenient tool for further development of analytical solution of specified time-dependent inlet boundary conditions or numerical evaluation of the concentration field for arbitrary time-dependent inlet boundary problem.
Top-down analysis of collated streamflow data from heterogeneous catchments leads to underestimation of land cover influence
Authors: van Dijk A. I. J. M. , Peña-Arancibia J. L. , (Sampurno) Bruijnzeel L. A.
Published: April 2011

Abstract. Controlled experiments have provided strong evidence that changing land cover (e.g. deforestation or afforestation) can affect the water balance. However a similarly strong influence has not been detected in analyses of collated streamflow data from catchments with mixed land cover. We tried to explain this "land cover paradox" using streamflow observations from 278 Australian catchments, a "top-down" model (the Zhang formulation of the Budyko model); and a "bottom-up" dynamic hydrological process model (the Australian Water Resources Assessment system Landscape model, AWRA-L). Analysis with the Zhang model confirmed the previously reported absence of a strong land cover signal. However, absence of evidence does not equate to the proof of absence, and AWRA-L was able to reconcile the streamflow data from the 278 catchments with experimental knowledge. Experiments were performed in which the Zhang model was used to analyse synthetic AWRA-L streamflow simulations for the 278 catchments. This demonstrated three reasons why the Zhang model did not accurately quantify the land cover signal: (1) measurement and estimation errors in land cover, precipitation and streamflow, (2) the importance of additional climate factors; (3) the presence of covariance in the streamflow and catchment attribute data. These methodological issues are likely to prevent the use of any top-down method to quantify land cover signal in data from catchments with mixed land cover. Our findings do not rule out physical processes that diminish land cover influence in catchments with mixed land cover, including atmospheric feedback associated with rainfall interception.
Particle flow and segregation in a giant landslide event triggered by the 2008 Wenchuan earthquake, Sichuan, China
Authors: Zhang L. M. , Xu Y. , Huang R. Q. , Chang D. S.
Published: April 2011

Abstract. During the 12 May 2008 Wenchuan earthquake, a large landslide of approximately 30 million m3 occurred at Donghekou with a particle run-out distance of over 2000 m. This paper presents fascinating particle flow and segregation characteristics in the landslide process found through field investigation of changes in the soil particle size, density, and fabric along the particle movement paths. The soil particles experienced projection, long-distance flying, sliding, and rolling. Trajectory segregation, inverse grading, and particle crushing were found in the landslide event, which contributed to the heterogeneity of the soil deposits. In the initial deposition area, particles with larger diameters appeared to have flown longer. Materials from different sources mixed, forming more uniform debris. In the run-out area, the particle flow tended to cause large particles to travel further. However, particle disintegration and crushing led to more small particles along the movement paths and the observed characteristic flow distances of very large particles did not increase with the particle diameter, which is different from observations of an idealized granular mass flow.
Luminosity Function of Some Open Clusters
Authors: Elsanhoury W. H. , Hamdy M. A. , Nouh M. I. , Saad A. S. , Saad S. M.
Published: April 2011

We investigated the luminosity function (LF) and initial mass function (IMF) of some open clusters having different ages. To calculate the LF, we followed the classical definition by van Rhijn (1936). Statistical investigation of the dispersion around a range of magnitudes concerning what is called Wielen dip revealed that the dip is unreal. To confirm the unreality of the dip, we computed the IMF for these open clusters, the statistical investigation of the IMF confirmed the results obtained using the LF, that is, there is no dip for these open clusters under study.
Coronary Artery Perforation and Regrowth of a Side Branch Occluded by a Polytetrafluoroethylene-Covered Stent Implantation
Authors: Y-Hassan Shams , Sylvén Christer , Henareh Loghman
Published: April 2011

Stenting of the right coronary artery stenosis caused coronary perforation and profound dye (blood) extravasation in a 69-year-old female patient. Instantaneous balloon inflation followed by implantation of a polytetrafluoroethylene- (PTFE-)covered stent sealed the coronary perforation, restored the blood flow, and perceivably caused acute occlusion of a large side branch (SB). The immediate in situ balloon inflation prevented the development of cardiac tamponade. Surprisingly, followup coronary angiography 4 and 11 months later showed spontaneous recanalization of the SB occluded by PTFE-covered stent. The SB was filled through a channel beginning at the end of the covered stent streaming retrogradely beneath it toward the SB ostium. Up to the best of our knowledge, this is the first described case of late spontaneous recanalization of as SB occluded by a PTFE-covered stent.
An Exploratory Investigation of Some Statistical Summaries of Oximeter Oxygen Saturation Data from Preterm Babies
Authors: Lee Dominic S. , Zahari Marina , Russell Glynn , Darlow Brian A. , Scarrott Carl J. , Reale Marco
Published: April 2011

Aim. To explore the potential usefulness of the mean, standard deviation (SD), and coefficient of variation (CV = SD/mean) of oximeter oxygen saturations in the clinical care of preterm babies. Methods. This was an exploratory investigation involving 31 preterm babies at 36 weeks postmenstrual age. All babies were healthy, but two were considered to be clinically unstable and required greater attention. Each baby's oxygen saturations were recorded using an oximeter and summarized by the mean, SD, and CV. The potential usefulness of each measure was assessed by its ability to distinguish the two unstable babies from the others. This was achieved using box plots and hierarchical clustering together with the Calinski-Harabasz (CH) index to quantify clustering performance (higher CH index indicates stronger clustering outcome). Results. The box plots flagged both unstable babies as outliers and none of the other babies. Successful clustering of the stable and unstable babies was achieved using the CV (CH = 72.8) and SD (CH = 63.3) but not with the mean. Conclusion. Taking the box plots and clustering results together, it seems plausible that variability might be more effective than mean level for detecting instability in oxygen saturation in preterm babies and that the combination of variability and level through the CV might be even better.
Reducing Needle Stick Injuries in Healthcare Occupations: An Integrative Review of the Literature
Authors: Yang Lin , Mullan Barbara
Published: April 2011

Needlestick injuries frequently occur among healthcare workers, introducing high risk of bloodborne pathogen infection for surgeons, assistants, and nurses. This systematic review aims to explore the impact of both educational training and safeguard interventions to reduce needlestick injuries. Several databases were searched including MEDLINE, PsycINFO, SCOPUS, CINAHL and Sciencedirect. Studies were selected if the intervention contained a study group and a control group and were published between 2000 and 2010. Of the fourteen studies reviewed, nine evaluated a double-gloving method, one evaluated the effectiveness of blunt needle, and one evaluated a bloodborne pathogen educational training program. Ten studies reported an overall reduction in glove perforations for the intervention group. In conclusion, this review suggests that both safeguard interventions and educational training programs are effective in reducing the risk of having needlestick injuries. However, more studies using a combination of both safeguards and educational interventions in surgical and nonsurgical settings are needed.
Non-Fourier Heat Conduction Analysis with Temperature-Dependent Thermal Conductivity
Authors: Rahideh H. , Malekzadeh P. , Golbahar Haghighi M. R.
Published: April 2011

As a first endeavor, the one- and two-dimensional heat wave propagation in a medium subjected to different boundary conditions and with temperature-dependent thermal conductivity is studied. Both the spatial as well as the temporal domain is discretized using the differential quadrature method (DQM). This results in superior accuracy with fewer degrees of freedom than conventional finite element method (FEM). To verify this advantage through some comparison studies, a finite element solution ise also obtained. After demonstrating the convergence and accuracy of the method, the effects of different parameters on the temperature distribution of the medium are studied.
Bioremediation of Pharmaceuticals, Pesticides, and Petrochemicals with Gomeya/Cow Dung
Authors: Randhawa Gurpreet Kaur , Kullar Jagdev Singh
Published: April 2011

Use and misuse of pharmaceuticals, pesticides, and petrochemicals by man is causing havoc with nature, as they persist as such or as their toxic metabolites. These pollutants bioaccumulate in environment, and they ultimately reach man through various means. They are hazardous because of potential toxicity, mutagenicity, carcinogenicity, and genotoxicity. To rejuvenate nature, remediation methods currently available are usually expensive and might convert one toxic pollutant to another. Bioremediation methods use naturally occurring microorganisms to detoxify man-made pollutants so that they change pollutants to innocuous products that make soil fertile in the process. Taking cue from Ayurveda, Gomeya/cow dung is used as an excellent bioremediation method. Thus, utilizing freely available cow dung as slurry or after composting in rural areas, is a cheap and effective measure to bioremediate the harmful pollutants. Yet, more research in this direction is warranted to bioremediate nonbiodegradable, potentially toxic pollutants.
Statistical Effects in the Solar Activity Cycles during AD 1823–1996
Authors: Ogurtsov Maxim , Lindholm Markus
Published: April 2011

General statistical properties of solar activity cycles during the period AD 1823–1996—including the Gnevyshev-Ohl and Waldmeier effects as well as an amplitude-period effect—were analyzed using Wolf number, group sunspot number, and extended total sunspot area series. It was found out that the Gnevyshev-Ohl effect GO2 (the positive correlation between intensity of the even cycles 2N and intensity of the odd cycles 2N+1) and the Waldmeier effect W2 (the anticorrelation between rise times of sunspot cycles and their amplitudes) are the most universal and robust features of the solar cycle. Other statistical relations were found appreciably sensitive to the selection of solar index, the interval of analysis, and the way of the cycle feature determination.
GCK-MODY (MODY 2) Caused by a Novel p.Phe330Ser Mutation
Authors: Bonfig Walter , Hermanns Sandra , Warncke Katharina , Eder Gabriele , Engelsberger Ilse , Burdach Stefan , Ziegler Annette Gabriele , Lohse Peter
Published: April 2011

Maturity onset diabetes of the young (MODY) is a monogenic form of diabetes inherited as an autosomal dominant trait. The second most common cause is GCK-MODY due to heterozygous mutations in theGCKgene which impair the glucokinase function through different mechanisms such as enzymatic activity, protein stability, and increased interaction with its receptor. The enzyme normally acts as a glucose sensor in the pancreatic beta cell and regulates insulin secretion. We report here a three-generation nonobese family diagnosed with diabetes. All affected family members presented with mild hyperglycemia and mostly slightly elevated hemoglobin A1c values. Genetic testing revealed a novel heterozygous T → C exchange in exon 8 of theGCKgene which resulted in a phenylalanine330TTC → serine (TCC)/p.Phe330Ser/F330S substitution.
Modulating Effect of Ascorbic Acid on Transport-Induced Immunosuppression in Goats
Authors: Minka Ndazo Salka , Ayo Joseph Olusegun
Published: April 2011

The effect of 12 h road transportation on some basic blood cells and the modulating role of ascorbic acid were investigated in 40 adult Red Sokoto goats during the hot dry season. The animals were divided into two groups, GI (experimental; ) and GII (control; ). Group 1 was administered with ascorbic acid (AA) per os at a dosage rate of 100 mg/kg body weight, while GII was given 10 mL of sterile water per goat. Forty minutes after the administration and loading, the goats were transported for 12 h. The result obtained in GII goats showed that loading, transportation, high ambient temperature (AT), and relative humidity (RH) encountered during transportation induced lymphopenia, neutrophilia, and eosinopenia, which can cause immunosuppression. In GI goats, the administration of AA prior to loading and transportation ameliorated the adverse effects of loading and transportation stress on neutrophil/lymphocyte ratio and eosinopenia of the goats.
Association of Epidermal Growth Factor Receptor Mutations with Metastatic Presentations in Non-Small Cell Lung Cancer
Authors: Na Im Il , Park Jong Heon , Choe Du Hwan , Lee Jin Kyung , Koh Jae Soo
Published: April 2011

We performed this retrospective study to assess the association of epidermal growth factor receptor (EGFR) with metastatic presentations in advanced non-small cell lung cancer (NSCLC). The data from 125 patients with stage III or IV NSCLC were analyzed. We detected EGFR mutations in 36 NSCLC patients. EGFR mutations were predominant in never-smokers , patients with adenocarcinomas , and female patients . When the metastatic sites were analyzed, pleural metastases were associated with a high incidence of EGFR mutations . Particularly, pleural metastases with minimal effusion (PMME) were associated with EGFR mutational status . Patients with N3 lesions were less likely to harbor EGFR mutations . On multivariate analysis, N3 lesions and PMME remained significant factors for EGFR mutations. EGFR mutations may be associated with different presentations of pleural and N3 nodal metastases.
Vaginal Inflammatory Status in Pregnant Women with Normal and Pathogenic Microbiota in Lower Genital Tract
Authors: Galiñanes Sebastián , Coppolillo Enrique , Cifarelli Maximiliano , Cora Eliseht Martha , Pellisa Ercilia , Losada Mirta , Gruccio Sebastián , Ruda Vega Hilda , Vay Carlos , Famiglietti Angela , Perazzi Beatriz
Published: April 2011

Objective. To assess the vaginal inflammatory status (VIS) in pregnant women, whether symptomatic or asymptomatic, by leukocyte quantification in relation to the microbiota during each pregnancy trimester (T). Materials and Methods. A thousand two hundred and forty eight vaginal exudates from pregnant women were prospectively examined. All the patients underwent a clinical and colposcopic examination and a microbiological study of vaginal exudates. Leukocyte quantification was determined by May-Grunwald Giemsa staining as LNR per field (400X). Results. Statistically significant differences (SSD) in LNR were observed in the VIS of asymptomatic patients (AP) compared with that of symptomatic ones (SP) with normal microbiota: 10–15 for the 1st T, <10, 20 to 25 and >25 for the 2nd T and >25 for the 3rd; with candidiasis:
<10 for the 1st T, <10, 15 to 20 and >25 for the 2nd T and <10 and >25 for the 3rd T. In women with trichomoniasis, SSD in the LNR were observed between SP with LNR ≥ 10 and AP with NLR < 10 in the three trimesters altogether. In women with BV, no SSD were observed in the LNR of any AP with respect to SP for the three T. Conclusion. The VIS is influenced by vaginal microbiota and depends on the state of pregnancy and also, on gestational age. The pronounced leukocyte increase in asymptomatic patients in the absence of lower genital tract infection during the third trimester of pregnancy should be highlighted.
Relationship between Damping Factor and Compressive Residual Stress for Shot-Peened Austenitic Stainless Steel
Authors: Singh Lakhwinder , Khan R. A. , Aggarwal M. L.
Published: April 2011

The mechanical properties of austenitic stainless steel are rarely improved by heat treatment. Shot peening is a well-known cold working process that affects thin surface of materials. By controlling the shot peening intensity and shot size, the variable mechanical properties film thickness was obtained from 0.05 mm to 0.5 mm. The damping factor and compressive residual stress are determined experimentally and forming a relation between them. It was found that damping factor in thin film surface increases with depth of deformed layer. An investigation was carried out, and it was found that the increase in damping factor was due to introduction of compressive residual stress and increased hardness due to shot peening. The paper discusses a model of changing damping properties with compressive residual stress and depth of deformed layer of austenitic stainless steel.
Vibrational Study of Fluid-Filled Functionally Graded Cylindrical Shells Resting on Elastic Foundations
Authors: Shah Abdul Ghafar , Mahmood Tahir , Naeem Muhammad Nawaz , Arshad Shahid Hussain
Published: April 2011

Vibrational characteristics of functionally graded cylindrical shells filled with fluid and placed on Winkler and Pasternak elastic foundations are investigated. Love's thin-shell theory is utilized for strain-displacement and curvature-displacement relationships. Shell dynamical equations are solved by using wave propagation approach. Natural frequencies for both empty and fluid-filled functionally graded cylindrical shells based on elastic foundations are determined for simply-supported boundary condition and compared to validate the present technique. Results obtained are in good agreement with the previous studies. It is seen that the frequencies of the cylindrical shells are affected much when the shells are filled with fluid, placed on elastic foundations, and structured with functionally graded materials. The influence of Pasternak foundation is more pronounced than that of Winkler modulus.
Survival after Drowning with Cardiac Arrest and Mild Hypothermia
Authors: Rudolph S. S. , Barnung S.
Published: April 2011

The current guidelines for resucitation following hypothermia and submersion with cardiac arrest state that rewarming should be continued until a core temperature of 32–34°C is achieved, after which death can be declared if no return of spontaneous circulation has occurred. As no randomized, controlled trials exist, these treatment guidelines are mostly based on a pragmatic approach. Wheater to start or stop resuscitation is notoriusly difficult. Submersion time, water temperature, and prompt resuscitation seem to be crucial factors for outcome. We report a case of successful resuscitation after the use of mechanical chest compressions and extracorporeal circulation in a patient with cardiac arrest due to submersion and accompanying mild hypothermia with a core temperature of 32,2°C caused by submersion.
Success Rate of Microimplants in a University Orthodontic Clinic
Authors: Sharma P. , Valiathan A. , Sivakumar A.
Published: April 2011

Introduction. The purpose of this study was to examine the success rate and find factors affecting the clinical success of microimplants used as orthodontic anchorage. Methods. Seventy-three consecutive patients (25 male, 48 female; mean age, 22.45 years) with a total of 139 screw implants of 2 types were examined. Success rate was determined according to 18 clinical variables. Results. The overall success rate was 87.8%. The clinical variables of microimplant factors (type), patient factors (sex, skeletal and dental relationships, overbite, jaw involved, side involved and site involved), and treatment factors (type of insertion, time of loading, purpose of microimplant insertion, mode of loading, type of anchorage used, direction of forces applied) did not show any statistical difference in success rates. Mandibular angle, vertical position of implant placement, oral hygiene status, and inflammation showed significant difference in success rates. Conclusions. Proper case selection and following the recommended protocol are extremely essential to minimise failures.
Modeling the effects of weaning age on length of female reproductive period: Implications for the evolution of human life history
Authors: Kachel A. Friederike , Premo L.S. , Hublin Jean‐Jacques
Published: April 2011

Objectives:

Human life history is unique among primates. Despite our extended lifespan, the length of the female reproductive period is shorter in humans than in our closest living relatives, chimpanzees. Here, we investigate whether this difference could be explained by another unique aspect of human life history—a young weaning age.

Methods:

Age‐dependent female fertility is modeled with the Brass polynomial. We model female reproductive period length as single locus with multiple alleles. Selection acts on the length of the female reproductive period in an evolutionary agent‐based simulation. We quantify the effect of weaning age on the optimal length of the female reproductive period under a range of adult mortality rates.

Results:

Females sacrifice a smaller proportion of their reproductive potential due to nursing by weaning their offspring at younger ages. As a consequence, the optimal length of the female reproductive period decreases as weaning age decreases, even when adult mortality is low.

Conclusions:

Natural selection will favor mutations or strategies that can decrease weaning age without incurring fitness costs. In the presence of younger weaning ages, selection favors a shorter female reproductive period. To the extent that allocare can decrease weaning age without decreasing fitness, its ubiquity in human societies and near absence in other primate societies may explain why women have a shorter reproductive period. Furthermore, allocare may have provided human ancestors with an avenue to decreased weaning age—and, ultimately, a shorter female reproductive period—that was unavailable to their hominoid contemporaries. Am. J. Hum. Biol. 2011. © 2011Wiley‐Liss, Inc.
Caregiving, gender, and nutritional status in Nyanza Province, Kenya: Grandmothers gain, grandfathers lose
Authors: Ice Gillian H. , Heh Victor , Yogo Jaja , Juma Elizabeth
Published: April 2011

Based on anecdotal and qualitative reports, a general assumption is that caregiving negatively impacts grandparents in Africa.

Objectives:

The purpose of this article is to determine how caregiving and gender impact nutritional status over four waves of data from Luo elders.

Methods:

Luo elders, aged 60 and over (age 73.6 ± 7.9) were sampled. Participant recruitment was rolling and included 287 Luo grandparents in 2005, 396 in 2006, 389 in 2007, and 390 in 2009. A total of 689 elders participated in at least 1 year. Standard anthropometric measures were used to determine nutritional status. Impact of caregiving was examined using structural equation models.

Results:

Caregiving positively associated with nutritional status among women. This main effect was mediated by caregiving intensity, which also positively associated with nutritional status. Among men, caregiving negatively associated with nutritional status, although caregiving intensity did not significantly associate with most anthropometric measures. Socioeconomic status (SES) positively associated with five of nine anthropometric measures in women and all measures in men. Several measures indicated that both men and women became larger over time but few of the variables tested predicted growth.

Conclusions:

The beneficial impact on grandmothers might indicate a coping strategy. These results indicated that researchers should shift away from comparing caregivers to noncaregivers and instead look at the multiple factors which may make some families resilient and others at risk. Human biologists can contribute to this literature by examining the ecological and cultural contexts under which caregiving represents a burden with physiological repercussions. Am. J. Hum. Biol. 2011. © 2011Wiley‐Liss, Inc.
Bilden und Brechen von Peptidbindungen: Protein‐Engineering mithilfe von Sortase
Authors: Popp Maximilian Wei‐Lin , Ploegh Hidde L.
Published: April 2011

Sortasen gehören zu einer Klasse bakterieller Enzyme, die Transpeptidaseaktivität aufweisen. Die Fähigkeit, Peptidbindungen ortsspezifisch zu brechen und neue Bindungen mit einem angreifenden Nukleophil zu bilden, macht Sortase zu einem hervorragenden Hilfsmittel für das Protein‐Engineering. Diese Methode wurde für eine Reihe von Anwendungen angepasst, die von der Chemie über die Zellbiologie bis hin zu technischen Gebieten reichen. Wir wollen hier einen kurzen Überblick über die Biologie der Sortaseenzyme und ihre Anwendungen im Protein‐Engineering geben, auf Gebiete für zukünftige Innovationen hinweisen und neue Anwendungen vorschlagen.
Cp2ZrCl2‐induced Reformatsky and Barbier reactions on isatins: an efficient synthesis of 3‐substituted‐3‐hydroxyindolin‐2‐ones
Authors: Chouhan Mangilal , Sharma Ratnesh , Nair Vipin A.
Published: April 2011

A mild and rapid one‐pot process for Reformatsky and Barbier reactions using a catalytic quantity of zirconocene dichloride (Cp2ZrCl2) as a promoter and zinc as a terminal reductant at room temperature in dimethyl formamide was developed. The protocol has wide substrate suitability and afforded the desired 3‐substituted‐3‐hydroxyindolin‐2‐ones from istains in good yields and short reaction time. Copyright © 2011 John Wiley & Sons, Ltd.
A Suzuki‐type cross‐coupling reaction of arylacetylene halides with arylboronic acids
Authors: Shi Yu , Li Xiaoyu , Liu Jianhui , Jiang Wenfeng , Sun Licheng
Published: April 2011

A PdCl2‐catalyzed direct alkynylation of arylboronic acids to give diarylacetylenes is described. The optimal conditions using PdCl2 as catalyst, MeOHPhMeH2O as solvent and K2CO3 as base effectively suppressed the formation of homo‐coupling product and afforded moderate to good yield of the desired unsymmetrical coupling product. This reaction represents a Suzuki‐type sp2(CB)–sp(CX) cross‐coupling. Copyright © 2011 John Wiley & Sons, Ltd.
Polyacrylamide‐grafted carboxymethyl cellulose: Smart pH‐sensitive hydrogel for protein concentration
Authors: Eldin M. S. Mohy , El‐Sherif H. M. , Soliman E. A. , Elzatahry A. A. , Omer A. M.
Published: April 2011

A novel application, utilizing polyacrylamide‐g‐carboxymethyl cellulose (CMC‐g‐PAM) in concentrating dilute solutions of Bovine serum albumin (BSA), was investigated. The grafting reaction parameters were investigated and the hydrogel smartness was verified. FT‐IR proved that the grafting reaction occurred between the hydroxyl group located in anhydroglucose C2 position of CMC and the π‐bond of PAM and SEM confirmed a changed morphology to a fibrillar structure. The pH sensitivity was proved; as the grafted polymer attained its maximum swelling at pH 7.2 while the minimum swelling was observed under acidic conditions (pH 1‐3). The rate of water uptake in the grafted polymer hydrogel was higher than that of the homopolymer hydrogel and the swelling behaviors of both hydrogels obeyed second‐order kinetics. The tested hydrogel showed a high potency towards concentrating BSA solutions with a concentration factor of 1 to 4.5 times and recovery of 60–90%. The concentration factor increased linearly with increasing both the polymer concentration and the process time and decreased with the increase in the protein concentration. The grafted polymer had stable efficiency in the concentration process for 20 cycles. The obtained results have recommended the employment of the prepared CMC‐g‐PAM hydrogel in the down stream protein concentration process in the industrial scale. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Thermal behavior and kinetics during the stabilization of polyacrylonitrile precursor in inert gas
Authors: Xiao Shijie , Lv Honghong , Tong Yuanjian , Xu Lianghua , Chen Biaohua
Published: April 2011

The thermal behaviors of polyacrylonitrile precursor during thermal stabilization in inert gas were investigated by differential scanning calorimetry, thermomechanical analysis, and thermogravimetry. Combining these methods with the tracing of chemical changes by Fourier transform infrared spectroscopy indicated that complex reactions, including cyclization and pyrolytic reactions occurred sequentially. An imine‐enamine tautomeric structure was formed at around 240°C and was converted to a conjugated structure when the temperature was increased to 400°C. A thermal stabilization mechanism was proposed and confirmed experimentally by using a two‐step heating process. The apparent activation energies and the pre‐exponential factors for these stabilization reactions were also estimated by the Kissinger, Ozawa, and “Improved Coats‐Redfern” methods. To obtain a fit to the experiment data, a new kinetic model, named the “Three Regions Kinetic Model,” was proposed using the Improved Coats‐Redfern method. The applicability of this model and the prediction of the stabilization profile at a given heating rate were verified by plotting conversion rate against conversion profiles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Polymerization of styrene using novel bispyrazolylimine dinickel (II)/methylaluminoxane catalytic systems
Authors: Wang Yuan‐yuan , Li Ben‐xia , Zhu Fang‐ming , Gao Hai‐yang , Wu Qing
Published: April 2011

The polymerization of styrene with a series of bispyrazolylimine dinickel (II) complexes of bis‐2‐(C3HN2(R1)2‐3,5)(C(R2) = N(C6H3(CH3)2‐2,6)Ni2Br4 (complex 1: R1 = CH3, R2 = Ph; complex 2: R1 = CH3, R2 = 2,4,6‐trimethylphenyl; complex 3: R1 = R2 = Ph; complex 4: R1 = Ph, R2 = 2,4,6‐trimethylphenyl) in the presence of methylaluminoxane (MAO) was studied. The influences of polymerization parameters such as polymerization temperature, Al/Ni molar ratio, reaction time, and catalyst concentration on catalytic activity and molecular weight of the polystyrene were investigated in detail. The influence of the bulkiness of the substituents on polymerization activity was also studied. All of the four catalytic systems exhibited high activity (up to 10.50 × 105 gPS/(mol Ni h)) for styrene polymerization and provide polystyrene with moderate to low molecular weights (Mw = 4.76 × 104–0.71 × 104 g/mol) and narrower molecular weight distributions about 2. The obtained polystyrene was characterized by means of FTIR, 1H‐NMR, and 13C‐NMR techniques. The results indicated that the polystyrene was atactic polymer. The analysis of the end groups of polystyrene indicated that styrene polymerization with bispyrazolylimine dinickel complexes/MAO catalytic systems proceeded through a coordination mechanism. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
“Digit anatomy”: A new technique for learning anatomy using motor memory
Authors: Oh Chang‐Seok , Won Hyung‐Sun , Kim Kyong‐Jee , Jang Dong‐Su
Published: April 2011

Gestural motions of the hands and fingers are powerful tools for expressing meanings and concepts, and the nervous system has the capacity to retain multiple long‐term motor memories, especially including movements of the hands. We developed many sets of successive movements of both hands, referred to as “digit anatomy,” and made students practice the movements which express (1) the aortic arch, subclavian, and thoracoacromial arteries and their branches, (2) the celiac trunk, superior mesenteric artery and their branches, and formation of the portal vein, (3) the heart and the coronary arteries, and (4) the brachial, lumbar, and sacral plexuses. A feedback survey showed that digit anatomy was helpful for the students not only in memorizing anatomical structures but also in understanding their functions. Out of 40 students, 34 of them who learned anatomy with the help of digit anatomy were “very satisfied” or “generally satisfied” with this new teaching method. Digit anatomy that was used to express the aortic arch, subclavian, and thoracoacromial arteries and their branches was more helpful than those representing other structures. Although the movements of digit anatomy are expected to be remembered longer than the exact meaning of each movement, invoking the motor memory of the movement may help to make relearning of the same information easier and faster in the future. Anat Sci Educ 4:132–141, 2011. © 2011 American Association of Anatomists.
The almost sure asymptotic stability and pth moment asymptotic stability of nonlinear stochastic delay differential systems with polynomial growth
Authors: Liu Lei , Shen Yi
Published: April 2011

In this paper, we discuss the asymptotic stability of nonlinear stochastic delay differential systems (SDDSs) whose coefficients obey the polynomial growth condition. By applying some novel techniques, we establish some easily verifiable conditions under which such SDDSs are almost surely asymptotically stable and pth moment asymptotically stable. A nontrivial example is provided to illustrate the effectiveness of our results.

Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Early fetal development of the intermediate tendon of the human digastricus and omohyoideus muscles: A critical difference in histogenesis
Authors: Katori Yukio , Hyun Kim Ji , Rodríguez‐Vázquez Jose Francisco , Kawase Tetsuaki , Murakami Gen , Hwan Cho Baik
Published: April 2011

The digastricus and omohyoideus muscles are known to carry two muscle bellies connected by an intermediate tendon. However, according to our histological observations of 22 fetuses (7–20 weeks of gestation), the mode of formation of the intermediate tendon was critically different between these two muscles. At 7–9 weeks, the posterior belly of the digastricus carried a definite intramuscular tendon continuous with a long descending tendon. The stylohyoideus, external carotid artery and hypoglossal nerve appeared to impede attachment of the tendon to the Reichert or hyoid cartilage. The digastricus anterior belly did not contain any intramuscular tendon, but desmin‐positive muscle fibers consistently surrounded a bulb‐like mesenchymal condensation at the caudal free end of the digastricus posterior tendon. Thus, most parts of the digastricus tendon were apparently derived from the posterior belly. In contrast, the omohyoideus always possessed a single long muscle belly until 15 weeks. The intermediate tendon first appeared at 15 weeks as a short plate‐like connective structure along the medial margin of the muscle. Vimentin immunoreactivity suggested the presence of mechanical stress along the plate‐like tissue, possibly due to bending of the long muscle. Muscle fibers were replaced by collagen fibers to form an intermediate tendon by 20 weeks. Clin. Anat. 24:843–852, 2011. © 2011 Wiley‐Liss, Inc.
Hierarchical Self‐Assembly of Amphiphilic Peptide Dendrons: Evolution of Diverse Chiral Nanostructures Through Hydrogel Formation Over a Wide pH Range
Authors: Duan Pengfei , Qin Long , Zhu Xuefeng , Liu Minghua
Published: April 2011

An amphiphilic dendron containing three dendrite L‐glutamic acid units and a long alkyl chain was synthesized by a convergent method. It was found that the dendron could form hydrogels over a wide pH range from 2 to 13. Moreover, accompanying the pH change, the compounds self‐assembled into various chiral structures: from helical nanotube, helical nanotube with a string of beads, and coiled superhelix to dendrite nanostructures, such as pine, feather, etc. A series of characterizations based on TEM observations, X‐ray diffraction and FTIR spectroscopic measurements revealed that the dendron formed a bilayer first and then hierarchically self‐assembled into various chiral nanostructures. The four carboxylic acid groups and three amide groups played an important role in the self‐assembly. The interaction between the multiamide groups stabilized the bilayer structures, whereas the ionization degree of the carboxylic acids was responsible for the formation of various chiral structures. The work presented a hydrogel system with wide pH adaptability and showed the regulation on chiral structures by simple pH variations.
Increasing the Isomerisation Kinetics of Azo Dyes by Chemical Bonding to Liquid‐Crystalline Polymers
Authors: Garcia‐Amorós Jaume , Finkelmann Heino , Velasco Dolores
Published: April 2011

It is well known that the proper substitution of the azobenzene core allows tuning the thermal cis‐to‐trans isomerisation kinetics of azo dyes. The thermal isomerisation process of nitro‐substituted azobenzenes is accelerated up to 13 times with respect to that in the common isotropic solvents when they are doped in nematic low molar mass liquid crystals. This kinetic acceleration is even stronger when these azo dyes are covalently linked to a nematic siloxane polymer. In this environment, the isomerisation process is accelerated more than 103 times. This effect is presented herein for the first time. The possible application of the networks obtained as possible photo‐actuators has been also considered.
On the Mechanism of Irreversible Carbon Dioxide Binding with a Frustrated Lewis Pair: Solvent‐Assisted Frustration and Transition‐State Entropic Encouragement
Authors: Kwon Hee Jae , Kim Hyun Woo , Rhee Young Min
Published: April 2011

The mechanism of irreversible carbon dioxide binding with a Lewis pair Mes3P:AlCl3 (Mes=2,4,6‐C6H2Me3) is computationally investigated to reveal that the steric congestion is not the driving force for the activation of CO2. Instead, we find that the specific solute–solvent interaction between the Lewis acid and a bromobenzene molecule lowers the effective binding energy of the Lewis pair. This solvation effect affects the reaction in a similar manner to the steric encumbering of conventional frustrated Lewis pairs. Additionally, the transition state toward the CO2 binding becomes extraordinarily flexible upon solvation. This flexibility encourages the adduct formation entropically and thus lowers the free‐energy barrier of the reaction. We conclude that this combination of energy‐barrier lowering through solvent‐assisted frustration and the entropic encouragement generates a feasible activation route for CO2 under mild conditions.
Controlling the Duality of the Mechanism in Liquid‐Phase Oxidation of Benzyl Alcohol Catalysed by Supported Au–Pd Nanoparticles
Authors: Sankar Meenakshisundaram , Nowicka Ewa , Tiruvalam Ramchandra , He Qian , Taylor Stuart H. , Kiely Christopher J. , Bethell Donald , Knight David W. , Hutchings Graham J.
Published: April 2011

In the solvent‐free oxidation of benzyl alcohol to benzaldehyde using supported gold–palladium nanoparticles as catalysts, two pathways have been identified as the sources of the principal product, benzaldehyde. One is the direct catalytic oxidation of benzyl alcohol to benzaldehyde by O2, whereas the second is the disproportionation of two molecules of benzyl alcohol to give equal amounts of benzaldehyde and toluene. Herein we report that by changing the metal oxide used to support the metal–nanoparticles catalyst from titania or niobium oxide to magnesium oxide or zinc oxide, it is possible to switch off the disproportionation reaction and thereby completely stop the toluene formation. It has been observed that the presence of O2 increases the turnover number of this disproportionation reaction as compared to reactions in a helium atmosphere, implying that there are two catalytic pathways leading to toluene.
Molecular Recognition at the Active Site of Catechol‐O‐methyltransferase (COMT): Adenine Replacements in Bisubstrate Inhibitors
Authors: Ellermann Manuel , Paulini Ralph , Jakob‐Roetne Roland , Lerner Christian , Borroni Edilio , Roth Doris , Ehler Andreas , Schweizer W. Bernd , Schlatter Daniel , Rudolph Markus G. , Diederich François
Published: April 2011

L‐Dopa, the standard therapeutic for Parkinson’s disease, is inactivated by the enzyme catechol‐O‐methyltransferase (COMT). COMT catalyzes the transfer of an activated methyl group from S‐adenosylmethionine (SAM) to its catechol substrates, such as L‐dopa, in the presence of magnesium ions. The molecular recognition properties of the SAM‐binding site of COMT have been investigated only sparsely. Here, we explore this site by structural alterations of the adenine moiety of bisubstrate inhibitors. The molecular recognition of adenine is of special interest due to the great abundance and importance of this nucleobase in biological systems. Novel bisubstrate inhibitors with adenine replacements were developed by structure‐based design and synthesized using a nucleosidation protocol introduced by Vorbrüggen and co‐workers. Key interactions of the adenine moiety with COMT were measured with a radiochemical assay. Several bisubstrate inhibitors, most notably the adenine replacements thiopyridine, purine, N‐methyladenine, and 6‐methylpurine, displayed nanomolar IC50 values (median inhibitory concentration) for COMT down to 6 nM. A series of six cocrystal structures of the bisubstrate inhibitors in ternary complexes with COMT and Mg2+ confirm our predicted binding mode of the adenine replacements. The cocrystal structure of an inhibitor bearing no nucleobase can be regarded as an intermediate along the reaction coordinate of bisubstrate inhibitor binding to COMT. Our studies show that solvation varies with the type of adenine replacement, whereas among the adenine derivatives, the nitrogen atom at position 1 is essential for high affinity, while the exocyclic amino group is most efficiently substituted by a methyl group.
Efficient Copper‐Catalyzed Synthesis of Poly‐N‐Heterocycles Containing Amino Acid Residues
Authors: Liu Tao , Wang Ruji , Yang Haijun , Fu Hua
Published: April 2011

An efficient copper‐catalyzed method has been developed for the synthesis of poly‐N‐heterocycles containing amino acid residues. The protocol uses readily available 2‐halobenzamides containing amino acids and their methyl esters, substituted phenylacetonitriles, and malononitrile as the starting materials and the reactions were performed well under mild conditions. The method should provide a novel and useful strategy for synthesis of N‐heterocyclic compounds.
Simultaneous Drug‐Eluting and Bare‐Metal Stent Implantation: Long‐Term Clinical Outcome and Findings of Clinically Indicated Coronary Angiography
Authors: Alexopoulos Dimitrios , Xanthopoulou Ioanna , Karantalis Vasileios , Mitropoulou Georgia , Damelou Anastasia , Davlouros Periklis
Published: April 2011

Background:

Simultaneous drug‐eluting stent (DES) and bare‐metal stent (BMS) implantation is occasionally employed in clinical practice, but its long‐term clinical and angiographic outcome is not clear.

Hypothesis:

We aimed to describe the long‐term clinical outcome and the findings of clinically indicated coronary angiography in patients subjected to simultaneous DES and BMS implantation (“hybrid stenting”).

Methods:

We identified 236 patients (mean age 62.9 ± 11.4 years, 76.7% men) who had undergone percutaneous coronary intervention with at least 1 DES and 1 BMS. At a median follow‐up of 42 months (range, 6–89 months) available in 222 patients, 13 (5.9%) patients died from cardiac causes, 13 (5.9%) experienced nonfatal acute myocardial infarction, and 24 (10.8%) experienced unstable angina. Clinically indicated repeat coronary angiography was performed in 64 patients (28.8%).

Results:

Thirty‐one patients (14%) had target lesion revascularization (TLR). The DES demonstrated lower TLR rates (15.9% vs 36.9%, P = 0.002) and lower late loss (0.44 ± 0.5 mm vs 0.68 ± 0.7 mm, P = 0.009) compared with BMS. Use of DES was independently associated with lower risk for binary restenosis (hazard ratio [HR]: 0.41, 95% confidence interval [CI]: 0.19–0.89, P = 0.03) and TLR (HR: 0.26, 95% CI: 0.12–0.54, P<0.001).

Conclusions:

Although a hybrid stenting strategy demonstrates a reasonable long‐term prognosis even in high‐risk patients, DES have a better angiographic outcome compared with BMS under the influence of common patient‐related restenosis risk factors. © 2011 Wiley Periodicals, Inc.

The authors have no funding, financial relationships, or conflicts of interest to disclose.
Long‐Term Outcomes of Sirolimus‐Eluting Stents vs Paclitaxel‐Eluting Stents in Unprotected Left Main Coronary Artery Bifurcation Lesions
Authors: Song Pil Sang , Ryu Dong Ryeol , Song Young Bin , Hahn Joo‐Yong , Choi Jin‐Ho , Choi Seung‐Hyuk , Lee Sang Hoon , Hong Kyung Pyo , Park Jeong Euy , Gwon Hyeon‐Cheol
Published: April 2011

Background:

The treatment of unprotected left main coronary artery (uLMCA) bifurcation lesions remains challenging.

Hypothesis:

We hypothesized that the type of drug‐eluting stent would correlate with clinical outcomes for the treatment of uLMCA bifurcation lesions.

Methods:

One hundred fifteen patients who underwent stent implantation using a provisional T‐stenting technique with sirolimus‐eluting stents (SES) or paclitaxel‐eluting stents (PES) for uLMCA bifurcation lesions were enrolled. A major adverse cardiac event (MACE) was defined as a composite of cardiac death, myocardial infarction, or target lesion revascularization.

Results:

Ninety‐four patients were treated with SES and 21 patients with PES. Baseline characteristics were similar between the 2 groups. Angiographic follow‐up was performed in 99 (86%) patients. Late loss in the LMCA to the left anterior descending coronary artery was significantly lower in the SES group than in the PES group (0.28 ± 0.54 mm vs 1.03 ± 0.45 mm, P<0.001). One case of stent thrombosis occurred in the SES group. During follow‐up with a median of 712 days, the SES group had a lower MACE compared with the PES group (10.6% vs 28.6%, P = 0.032). Cox proportional hazards models including age, sex, diabetes, acute coronary syndrome, true bifurcation, stenting strategy, and type of drug‐eluting stent used (SES vs PES) demonstrated that stent type was the only predictor of MACE (hazard ratio of PES vs SES: 3.88, 95% confidence interval: 1.29–11.67, P = 0.016).

Conclusions:

According to the results of the present study, SES may be associated with more favorable outcomes than PES for stenting of uLMCA bifurcation, which should be further studied by larger trials. © 2011 Wiley Periodicals, Inc.

The authors have no funding, financial relationships, or conflicts of interest to disclose.