bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of the protease activity of detergents laboratory practicals for studying the protease profile and activity of various commercial detergents
Authors: Valls Cristina , Pujadas Gerard , Garcia‐Vallve Santi , Mulero Miquel 
Published: July 2011

AbstractDetergent enzymes account for about 30% of the total worldwide production of enzymes and are one of the largest and most successful applications of modern industrial biotechnology. Proteases can improve the wash performance of household, industrial, and institutional laundry detergents used to remove protein‐based stains such as blood, grass, body fluids, and food soils. This article describes two easy and cheap laboratory exercises to study the presence, profile, and basic enzymology of detergent proteases. These laboratory practicals are based on the determination of the detergent protease activity of various commercial detergents using the N‐succinyl‐L‐alanyl‐L‐alanyl‐L‐prolyl‐L‐phenylalanine p‐nitroanilide method and the bovine serum albumin degradation capacity. Students are also required to elucidate the enzymatic subtype of detergent proteases by studying the inhibitory potential of several types of protease inhibitors revealed by the same experimental methodology. Additionally, the results of the exercises can be used to provide additional insights on elementary enzymology by studying the influence of several important parameters on protease activity such as temperature (in this article) and the influence of pH and effects of surfactants and oxidizers (proposed). Students also develop laboratory skills, problem‐solving capacities, and the ability to write a laboratory report. The exercises are mainly designed for an advanced undergraduate project in the biochemistry and biotechnology sciences. Globally, these laboratory practicals show students the biotechnological applications of proteases in the detergent industry and also reinforce important enzymology concepts. Biochemistry and Molecular Biology Education Vol. 39, No. 4, pp. 280‐290, 2011
A laboratory exercise illustrating the sensitivity and specificity of Western blot analysis
Authors: Chang Ming‐Mei , Lovett Janice 
Published: July 2011

AbstractWestern blot analysis, commonly known as “Western blotting,” is a standard tool in every laboratory where proteins are analyzed. It involves the separation of polypeptides in polyacrylamide gels followed by the electrophoretic transfer of the separated polypeptides onto a nitrocellulose or polyvinylidene fluoride membrane. A replica of the separated polypeptides from the gel is created on the membrane, which is then probed with antibodies or other ligands to identify specific polypeptide(s). Here, we report an undergraduate laboratory exercise involving Western blotting. During the 3‐week laboratory exercise, students investigated the likelihood of the presence of a serum albumin in fruit fly (Drosophila melanogaster) homogenate, bovine calf serum (BCS), and fetal bovine serum (FBS). Students isolate proteins from fruit fly larvae and perform sodium dodecylsulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE), electrophoretic blotting, and immunoassay comparing those proteins with BCS and FBS proteins. Their results indicate that serum albumin is present in BCS and FBS but is absent in fruit flies. In the process, the specificity and sensitivity of Western blot analysis is demonstrated. The laboratory exercise can be easily incorporated into any college‐level biochemistry or molecular techniques laboratory. The procedure used can be easily adapted to study other proteins. Biochemistry and Molecular Biology Education Vol. 39, No. 4, pp. 291‐297, 2011
The treasure of the humble: Lessons from Baker's yeast
Authors: Sitaraman Ramakrishnan 
Published: July 2011

AbstractThe study of model organisms is a powerful and proven experimental strategy for understanding biological processes. This paper describes an attempt to utilize advances in yeast molecular biology to enhance student understanding by presenting a more comprehensive view of several interconnected molecular processes in the overall functioning of an organism, and introducing the concept of the inverse problem as it relates to biology. Biochemistry and Molecular Biology Education Vol. 39, No. 4, pp. 261‐266, 2011
The pH ruler: A Java applet for developing interactive exercises on acids and bases
Authors: Barrette‐Ng Isabelle H. 
Published: July 2011

AbstractIn introductory biochemistry courses, it is often a struggle to teach the basic concepts of acid‐base chemistry in a manner that is relevant to biological systems. To help students gain a more intuitive and visual understanding of abstract acid‐base concepts, a simple graphical construct called the pH ruler Java applet was developed. The applet allows students to visualize the abundance of different protonation states of diprotic and triprotic amino acids at different pH values. Using the applet, the student can drag a widget on a slider bar to change the pH and observe in real time changes in the abundance of different ionization states of this amino acid. This tool provides a means for developing more complex inquiry‐based, active‐learning exercises to teach more advanced topics of biochemistry, such as protein purification, protein structure and enzyme mechanism. Biochemistry and Molecular Biology Education Vol. 39, No. 4, pp. 332‐338, 2011
Just give it a try: Assessing interactive ad‐hoc software‐evaluation behaviour
Authors: Zimmermann Jörg , Nerdinger Friedemann W. 
Published: July 2011

ABSTRACTThis study investigates actual consumer behaviour in end‐user software selection, a field that has been fairly neglected in extant research. The novel point we make is that the immaterial character of software—leading to its indestructibility and virtually cost‐free distribution—makes it easy for software manufacturers to let consumers evaluate computer programs hands‐on by trying them out in realistic settings. Detached paper‐and‐pencil methods for assessing consumers' predecision behaviour seem to be inadequate for modelling this type of evaluation in which individuals do not need to care about returning the object(s) in the same state. In this article, we present a methodology for and the first results of assessing unguided end‐user software evaluation behaviour in its natural complexity. Our exploratory approach focused on identifying a behavioural typology, as well as its relation to the choice result, which would have major implications for the design and distribution of demo versions, shareware, etc. Twenty individuals were subjected to a realistic choice problem involving direct interaction with real software products. Their behaviour was analyzed using a novel abstraction methodology. Results suggest the existence of four different evaluation types and the moderating influence of evaluation behaviour on choice result, which can be integrated into and plausibly explained by prevalent theory. Copyright © 2011 John Wiley & Sons, Ltd.
Catalytic Applications of Terpyridines and their Transition Metal Complexes
Authors: Winter Andreas , Newkome George R. , Schubert Ulrich S. 
Published: July 2011

AbstractThe coordination compounds of the tridentate oligopyridine ligand 2,2′:6′,2′′‐terpyridine (tpy) are utilized in very different fields of research, such as materials science (e.g. photovoltaics), biomedicinal chemistry (e.g. DNA intercalation), and organometallic catalysis. Applications in the latter area have arisen from initial reports on electro‐ or photochemical processes and, today, a broad range of reactions—from artificial photosynthesis (water splitting) to biochemical and organic transformations as well as polymerization reactions—have been catalyzed by terpyridines and their transition metal complexes. In this review, the scope and the limitations of these applications, which emerged particularly in organic and macromolecular chemistry, will be evaluated.
Atom‐Economic and Stereoselective Syntheses of the Ring A and B Subunits of the Bryostatins
Authors: Trost Barry M. , Yang Hanbiao , Brindle Cheyenne S. , Dong Guangbin 
Published: July 2011

AbstractThis article describes chemoselective and atom‐economic methods for the stereoselective assembly of the ring A and B subunits of bryostatins. A Ru‐catalyzed tandem alkene–alkyne coupling/Michael addition reaction was developed and applied to the synthesis of bryostatin ring B. We explored an acetylide‐mediated epoxide‐opening/6‐exo‐dig cyclization route to access the bryostatin ring A, although ring A was eventually furnished through an acid‐catalyzed tandem transketalization/ketalization sequence. In addition, a dinuclear zinc‐catalyzed methyl vinyl ketone (MVK) aldol strategy was evaluated for the construction of the polyacetate moiety. Utilization of these methods ultimately led to the rapid assembly of the northern bryostatin fragment containing both the ring A and B subunits.
Probing Charge Transfer between Shells of Double‐Walled Carbon Nanotubes Sorted by Outer‐Wall Electronic Type
Authors: Kalbac Martin , Green Alexander A. , Hersam Mark C. , Kavan Ladislav 
Published: July 2011

AbstractDouble‐walled carbon nanotubes (DWCNTs) with outer metallic (M) or semiconducting (S) shells were sorted by density‐gradient ultracentrifugation and examined by Raman spectroscopy and in situ Raman spectroelectrochemistry. The combination of sorting and the selection of appropriate laser excitation energies allowed the disentanglement of the effects of different variations of the electronic type (M or S) of the inner and outer tubes in DWCNTs on the doping behavior and charge transfer between the inner and outer walls. Charge transfer from the outer tube to the inner tube occurs only if the electronic states of the outer tube are filled with electrons or holes, and if these filled states are higher in energy than those of the inner tube. Therefore, each combination of inner and outer tube (i.e., inner@outer: M@M, M@S, S@M, and S@S) exhibits a distinct behavior. The potential needed to observe the effects of charge transfer between the inner and outer tubes is found to increase in the following order: M@M < S@M < M@S < S@S.
Cooperative and Reciprocal Chiral Structure Formation of an Alanine‐Based Peptide Confined at the Surface of Cationic Surfactant Membranes
Authors: Kiagus‐Armad Roni , Brizard Aurélie , Tang Claire , Blatchly Richard , Desbat Bernard , Oda Reiko 
Published: July 2011

AbstractThe confinement of anionic oligoalanine peptides at the surface of cationic membranes can cooperatively reinforce peptide/peptide interactions and induce secondary‐structure formation, and, reciprocally, induce chirality expression of the membrane at the mesoscopic level, thus leading to the formation of three‐dimensional chiral fibrillar networks. Such a strong binding effect of peptides with cationic membranes and the resulting cooperative assembly behaviors are observed with two different types of cationic surfactant, namely, two‐head two‐tail gemini and one‐head two‐tail surfactants. The ensemble of assembly properties, such as critical micellar concentration (cmc), Krafft temperature (Tk), molecular area at the air/water interface, molecular organization (as studied by FTIR attenuated total reflectance (ATR) measurements and small‐angle X‐ray scattering), and morphology of the aggregates (as observed by optical and electron microscopy studies), are reported. The results clearly demonstrate that the molecular organization and mesoscopic supramolecular structures are controlled by a subtle balance between the peptide/peptide interactions, ionic interactions between the membranes and peptides, and the interactions the between surfactant molecules, which are governed by hydrophobicity and steric interactions. Investigation into such cooperative organization can shed light on the mechanism of supramolecular chirality expression in membrane systems and allow understanding of the structure of peptides in interactions with lipid bilayers.
Theoretical Simulations Elucidate the Role of Naphthalenic Species during Methanol Conversion within H‐SAPO‐34
Authors: Hemelsoet Karen , Nollet Arno , Van Speybroeck Veronique , Waroquier Michel 
Published: July 2011

AbstractThe role of naphthalenic species during the methanol‐to‐olefins (MTO) process in a silicoaluminophosphate zeolitic material exhibiting the chabazite topology (H‐SAPO‐34) has been studied from first principles. These species could either act as active olefin‐eliminating compounds or as precursors for deactivating species. Results incorporating van der Waals contributions for finite large clusters point out that successive methylation steps of naphthalenic compounds are feasible. The calculated intrinsic activation barrier is relatively independent of the number of methyl groups already attached on the aromatic compound and is approximately 140 kJ mol−1. The influence of the composition of the catalyst and hence the acidic strength on the intrinsic chemical kinetics was investigated in detail through comparison with the isostructural high‐silicon material. Apparent chemical kinetics, starting from adsorbed methanol on the acid site, were also computed. The initiation steps of the side‐chain route starting from a trimethylated naphthalenium ion were also examined. The actual side‐chain methylation exhibits a high barrier and hence this mechanism involving methylated naphthalenes is not expected to be an active ethene‐eliminating route in H‐SAPO‐34.
A Computational Study on the Role of Chiral N‐Oxides in Enantioselective Pauson–Khand Reactions
Authors: Fjermestad Torstein , Pericàs Miquel A. , Maseras Feliu 
Published: July 2011

AbstractDensity functional calculations were carried out to ascertain the origin of enantioselectivity in the brucine N‐oxide (BNO)‐assisted enantioselective Pauson–Khand reaction (PKR) of norbornene with 2‐methyl‐3‐butyn‐2‐ol. The computed ee value in acetone is 68 % (R), which compares well to the previously reported experimental value of 58 % (R). In DME the computed ee value of 76 % (R) is in excellent agreement with the experimentally determined value of 78 % (R). The mechanism of enantioselectivity consists of several steps. First, the dicobalt complex is activated by BNO with chirality transfer from enantiopure BNO to the dicobalt complex. Second, competition occurs between a racemization process and complexation with the olefin reagent, which leads to the products. The lower ee value in acetone is due to the lower energy barrier of the racemization process. Calculations show that replacement of BNO by a hypothetical more enantioselective chiral N‐oxide will hardly increase the ee value beyond 90 %.
Functional polymorphisms of circadian positive feedback regulation genes and clinical outcome of Chinese patients with resected colorectal cancer
Authors: Zhou Feng , He Xianli , Liu Hanqiang , Zhu Yong , Jin Tianbo , Chen Chao , Qu Falin , Li Yunming , Bao Guoqiang , Chen Zhinan , Xing Jinliang 
Published: July 2011

AbstractBACKGROUND:Previous studies have demonstrated that circadian genes play a role in the development and progression of many cancers. This study aims to assess the effects of single nucleotide polymorphisms (SNPs) in circadian genes on recurrence and survival of colorectal cancer (CRC) patients.METHODS:Nine functional SNPs in 3 genes (CLOCK, NPAS2, and BMAL1) on the circadian positive feedback loop were selected and genotyped using the Sequenom iPLEX genotyping system in a cohort of 411 resected Chinese CRC patients. Multivariate Cox proportional hazards model and Kaplan‐Meier curve were used for the prognosis analysis.RESULTS:The authors identified 2 SNPs in the CLOCK gene to be significantly associated with CRC overall survival. SNP rs3749474 exhibited a significant association with survival of CRC patients in the additive model (hazard ratio [HR], 0.55; 95% confidence interval [CI], 0.37‐0.81; P = .003). In addition, patients carrying the heterozygous variant of rs1801260 had significantly increased overall survival compared with those carrying homozygous wild‐type genotype (HR, 0.31; 95% CI, 0.11‐0.88; P = .03). Findings from functional assay provided further biological support for these significant associations. Stratified analysis found no modifying effect of chemotherapy on the prognostic significance of both SNPs. Moreover, we observed cumulative effects of these 2 SNPs on CRC overall survival (P for trend = .01). Compared with patients carrying no unfavorable genotypes, those carrying 2 unfavorable genotypes had a 2.92‐fold increased risk of death (P = .03).CONCLUSIONS:The results suggest for the first time that CLOCK gene polymorphisms may serve as an independent prognostic marker for CRC patients. Cancer 2012;. © 2011 American Cancer Society.
Stereotactic radiosurgery of World Health Organization grade II and III intracranial meningiomas
Authors: Pollock Bruce E. , Stafford Scott L. , Link Michael J. , Garces Yolanda I. , Foote Robert L. 
Published: July 2011

AbstractBACKGROUND:A study was undertaken to define the variables associated with tumor control and survival after single‐session stereotactic radiosurgery (SRS) for patients with atypical and malignant intracranial meningiomas.METHODS:Fifty patients with World Health Organization (WHO) grade II (n = 37) or grade III (n = 13) meningiomas underwent SRS from 1990 to 2008. Most tumors were located in the falx/parasagittal region or cerebral convexities (n = 35, 70%). Twenty patients (40%) had progressing tumors despite prior external beam radiation therapy (EBRT) (median dose, 54.0 grays [Gy]). The median treatment volume was 14.6 cm3; the median tumor margin dose was 15.0 Gy. Seven patients (14%) received concurrent EBRT (median dose, 50.4 Gy). Follow‐up (median, 38 months) was censored at last evaluation (n = 28) or death (n = 22).RESULTS:Tumor grade correlated with disease‐specific survival (DSS) (hazard ratio [HR], 3.4; P = .008), local tumor control (HR, 2.4; P = .02), and progression‐free survival (PFS) (HR, 2.6; P = .02) on univariate analysis, but not on multivariate analysis. Multivariate analysis showed that having failed EBRT and tumor volume >14.6 cm3 were negative predictors of DSS and local control (HR, 3.0; P = .02 and HR, 4.4; P = .01; HR, 3.3; P = .001 and HR, 2.3; P = .02;, respectively). Having failed EBRT was a negative predictor of PFS (HR, 3.5; P = .002). Thirteen patients (26%) had radiation‐related complications at a median of 6 months after radiosurgery.CONCLUSIONS:Tumor progression despite prior EBRT and larger tumor volume are negative predictors of tumor control and survival for patients having SRS for WHO grade II and III intracranial meningiomas. Cancer 2012;. © 2011 American Cancer Society.
Cost‐effectiveness of modern radiotherapy techniques in locally advanced pancreatic cancer
Authors: Murphy James D. , Chang Daniel T. , Abelson Jon , Daly Megan E. , Yeung Heidi N. , Nelson Lorene M. , Koong Albert C. 
Published: July 2011

AbstractBACKGROUND:Radiotherapy may improve the outcome of patients with pancreatic cancer but at an increased cost. In this study, the authors evaluated the cost‐effectiveness of modern radiotherapy techniques in the treatment of locally advanced pancreatic cancer.METHODS:A Markov decision‐analytic model was constructed to compare the cost‐effectiveness of 4 treatment regimens: gemcitabine alone, gemcitabine plus conventional radiotherapy, gemcitabine plus intensity‐modulated radiotherapy (IMRT); and gemcitabine with stereotactic body radiotherapy (SBRT). Patients transitioned between the following 5 health states: stable disease, local progression, distant failure, local and distant failure, and death. Health utility tolls were assessed for radiotherapy and chemotherapy treatments and for radiation toxicity.RESULTS:SBRT increased life expectancy by 0.20 quality‐adjusted life years (QALY) at an increased cost of $13,700 compared with gemcitabine alone (incremental cost‐effectiveness ratio [ICER] = $69,500 per QALY). SBRT was more effective and less costly than conventional radiotherapy and IMRT. An analysis that excluded SBRT demonstrated that conventional radiotherapy had an ICER of $126,800 per QALY compared with gemcitabine alone, and IMRT had an ICER of $1,584,100 per QALY compared with conventional radiotherapy. A probabilistic sensitivity analysis demonstrated that the probability of cost‐effectiveness at a willingness to pay of $50,000 per QALY was 78% for gemcitabine alone, 21% for SBRT, 1.4% for conventional radiotherapy, and 0.01% for IMRT. At a willingness to pay of $200,000 per QALY, the probability of cost‐effectiveness was 73% for SBRT, 20% for conventional radiotherapy, 7% for gemcitabine alone, and 0.7% for IMRT.CONCLUSIONS:The current results indicated that IMRT in locally advanced pancreatic cancer exceeds what society considers cost‐effective. In contrast, combining gemcitabine with SBRT increased clinical effectiveness beyond that of gemcitabine alone at a cost potentially acceptable by today's standards. Cancer 2012;. © 2011 American Cancer Society.
Comparison of ThinPrep and SurePath liquid‐based cytology and subsequent human papillomavirus DNA testing in China
Authors: Zhao Fang‐Hui , Hu Shang‐Ying , Bian Jessica J. , Liu Bin , Peck Roger B. , Bao Yan‐Ping , Pan Qin‐Jing , Frappart Lucien , Sellors John , Qiao You‐Lin 
Published: July 2011

AbstractBACKGROUND:Liquid‐based cytology (LBC) has been compared with conventional cytology in numerous studies. In the current study of 2 LBC systems, the accuracy, rates of unsatisfactory cytology, and sufficiency of residual LBC specimens for Hybrid Capture 2 (HC2) HPV DNA testing were compared.METHODS:Eligible women ages 30 to 49 years were recruited for this cross‐sectional population‐based study in rural China. Women were assessed by visual inspection with acetic acid (VIA), LBC, and high‐risk HPV HC2 DNA assay. Cervical specimens were preserved according to SurePath or ThinPrep protocols. LBC results were manually read. HC2 testing was performed on specimens with sufficient residual volume. Colposcopies and biopsies were performed on women who were VIA positive at the time of initial screening. Women with abnormal LBC or HC2 test results were called back for colposcopies and 4‐quadrant cervical biopsies.RESULTS:Of 2005 eligible women, 972 were tested by SurePath and 1033 by ThinPrep. Compared with SurePath samples, ThinPrep samples had higher rates of unsatisfactory cytology (0.2% for SurePath and 1.5% for ThinPrep) and insufficient residual volume for HC2 (0.0% for SurePath and 18.2% for ThinPrep). SurePath samples yielded higher sensitivities and similar specificities for LBC and HC2 testing of residual specimens, but these differences were not determined to be significant by area‐under‐the‐curve analysis (LBC performance: 0.89 for SurePath and 0.85 for ThinPrep; HC2 performance: 0.91 for SurePath and 0.89 for ThinPrep).CONCLUSIONS:Both methods yielded similar validity in detecting significant cervical lesions. However, SurePath samples yielded higher rates of satisfactory LBC slides and sufficient residual volume for HC2. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society.
Two distinct types of ON directionally selective ganglion cells in the rabbit retina
Authors: Hoshi Hideo , Tian Lian‐Ming , Massey Stephen C. , Mills Stephen L. 
Published: July 2011

AbstractFour Neurobiotin‐injected coupled ON DS ganglion cells surrounding an ON‐OFF DS ganglion cell (white) show the relative size of these two cell types. The ganglion cells were colored in Adobe Photoshop for clarity. The Journal of Comparative Neurology, Volume 519, Number 13, pages 2509–2521.