bluuebunny/crossref_metadata_2025 huggingface dataset:
Combined spectroscopies and molecular docking approach to characterizing the binding interaction between lisinopril and bovine serum albumin
Authors: Jiang Min , Huang Chuan‐ren , Wang Qi , Zhu Ying‐yao , Wang Jing , Chen Jun , Shi Jie‐hua
Published: August 2015

To further understand the mode of action and pharmacokinetics of lisinopril, the binding interaction of lisinopril with bovine serum albumin (BSA) under imitated physiological conditions (pH 7.4) was investigated using fluorescence emission spectroscopy, synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD) and molecular docking methods. The results showed that the fluorescence quenching of BSA near 338 nm resulted from the formation of a lisinopril–BSA complex. The number of binding sites (n) for lisinopril binding on subdomain IIIA (site II) of BSA and the binding constant were ~ 1 and 2.04 × 104 M–1, respectively, at 310 K. The binding of lisinopril to BSA induced a slight change in the conformation of BSA, which retained its α‐helical structure. However, the binding of lisinopril with BSA was spontaneous and the main interaction forces involved were van der Waal's force and hydrogen bonding interaction as shown by the negative values of ΔG0, ΔH0 and ΔS0 for the binding of lisinopril with BSA. It was concluded from the molecular docking results that the flexibility of lisinopril also played an important role in increasing the stability of the lisinopril–BSA complex. Copyright © 2015 John Wiley & Sons, Ltd.
Environmental stress speeds up DNA replication in Pseudomonas putida in chemostat cultivations
Authors: Lieder Sarah , Jahn Michael , Koepff Joachim , Müller Susann , Takors Ralf
Published: August 2015

Cellular response to different types of stress is the hallmark of the cell's strategy for survival. How organisms adjust their cell cycle dynamics to compensate for changes in environmental conditions is an important unanswered question in bacterial physiology. A cell using binary fission for reproduction passes through three stages during its cell cycle: a stage from cell birth to initiation of replication, a DNA replication phase and a period of cell division. We present a detailed analysis of durations of cell cycle phases, investigating their dynamics under environmental stress conditions. Applying continuous steady state cultivations (chemostats), the DNA content of a Pseudomonas putida KT2440 population was quantified with flow cytometry at distinct growth rates. Data‐driven modeling revealed that under stress conditions, such as oxygen deprivation, solvent exposure and decreased iron availability, DNA replication was accelerated correlated to the severity of the imposed stress (up to 1.9‐fold). Cells maintained constant growth rates by balancing the shortened replication phase with extended cell cycle phases before and after replication. Transcriptome data underpin the transcriptional upregulation of crucial genes of the replication machinery. Hence adaption of DNA replication speed appears to be an important strategy to withstand environmental stress.
Alleviating product inhibition in cellulase enzyme Cel7A
Authors: Atreya Meera E. , Strobel Kathryn L. , Clark Douglas S.
Published: August 2015

Enzymes that degrade cellulose into glucose are one of the most expensive components of processes for converting cellulosic biomass to fuels and chemicals. Cellulase enzyme Cel7A is the most abundant enzyme naturally employed by fungi to depolymerize cellulose, and like other cellulases is inhibited by its product, cellobiose. There is thus great economic incentive for minimizing the detrimental effects of product inhibition on Cel7A. In this work, we experimentally generated 10 previously proposed site‐directed mutant Cel7A enzymes expected to have reduced cellobiose binding energies (the majority of mutations were to alanine). We then tested their resilience to cellobiose as well as their hydrolytic activities on microcrystalline cellulose. Although every mutation tested conferred reduced product inhibition (and abolished it for some), our results confirm a trade‐off between Cel7A tolerance to cellobiose and enzymatic activity: Reduced product inhibition was accompanied by lower overall enzymatic activity on crystalline cellulose for the mutants tested. The tempering effect of mutations on inhibition was nearly constant despite relatively large differences in activities of the mutants. Our work identifies an amino acid in the Cel7A product binding site of interest for further mutational studies, and highlights both the challenge and the opportunity of enzyme engineering toward improving product tolerance in Cel7A. Biotechnol. Bioeng. 2016;113: 330–338. © 2015 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.
Limitation of syntrophic coculture growth by the acetogen
Authors: Junicke Helena , Feldman Hannah , Van Loosdrecht Mark C. M. , Kleerebezem Robbert
Published: August 2015

The syntrophic cooperation between hydrogen‐producing acetogens and hydrogenotrophic methanogens relies on a critical balance between both partners. A recent study, provided several indications for the dependence of the biomass‐specific growth rate of a methanogenic coculture on the acetogen. Nevertheless, final experimental proof was lacking since biomass‐specific rates were obtained from a descriptive model, and not from direct measurement of individual biomass concentrations. In this study, a recently developed quantitative PCR approach was used to measure the individual biomass concentrations in the coculture of Desulfovibrio sp. G11 and Methanospirillum hungatei JF1 on lactate, formate or both. The model‐derived growth yields and biomass‐specific rates were successfully validated. Experimental findings identified the acetogen as the growth‐limiting partner in the coculture on lactate. While the acetogen was operating at its maximum biomass‐specific lactate consumption rate, the hydrogenotrophic methanogen showed a significant overcapacity. Furthermore, this study provides experimental evidence for different growth strategies followed by the syntrophic partners in order to maintain a common biomass‐specific growth rate. During syntrophic lactate conversion, the biomass‐specific electron transfer rate of Methanospirillum hungatei JF1 was three‐fold higher compared to Desulfovibrio sp. G11. This is to compensate for the lower methanogenic biomass yield per electron‐mole of substrate, which is dictated by the thermodynamics of the underlying reaction. Biotechnol. Bioeng. 2016;113: 560–567. © 2015 Wiley Periodicals, Inc.
Novel N‐(2,2′‐disubstituted‐2H‐cromenyl)‐N′,N″‐disubstituted Guanidine Derivatives as an S‐Nitrosoglutathion Reductase Inhibitor
Authors: Lee Gee‐Hyung , Nam Yeonju , Kim Eun‐Mi , Lim Su‐Jeong , Yang Seung‐Ju , Park Kyuhee , Choi Yongmun , Gong Young‐Dae
Published: August 2015

Novel N‐(2,2′‐disubstituted‐2H‐cromenyl)‐N′N″‐disubstituted guanidine derivatives were synthesized and evaluated as an S‐nitrosoglutathion (GSNO) reductase inhibitor. The synthesized guanidine derivatives 1 and 2b showed high potency in an enzyme‐based assay with recombinant GSNO reductase (IC50
< 10 μM). Surface plasmon resonance measurement and molecular docking studies confirmed the direct interaction of compound 2b with GSNO reductase. The results provide valuable information for the design of inhibitors with better spectrum of activity toward GSNO reductase.
Stability‐indicating HPLC‐DAD Method for Simultaneous Determination of Atorvastatin, Irbesartan, and Amlodipine in Bulk and Pharmaceutical Preparations
Authors: Bkhaitan Majdi M. , Mirza Agha Zeeshan
Published: August 2015

The present study describes a convenient stability‐indicating HPLC‐DAD method for the separation and simultaneous determination of the drugs atorvastatin, irbesartan, and amlodipine in bulk and formulations. The method proposed demonstrated good separation between atorvastatin, irbesartan, amlodipine and their main degradation products. Separation was executed on a Waters XBrigde C18 column (5 µm, 25 × 0.46 cm) using a gradient mobile phase system consisting of acetonitrile and orthophosphoric acid buffer (pH 2.2) at a flow rate of 1 mL/min and UV detection at 240 nm. The drugs were subjected to acidic and basic hydrolysis, oxidation, exposure to UV light, and exposure to temperature (dry heat) to apply stress conditions. Linearity of the method was evaluated in the range 5–30 µg/mL for each drug with correlation coefficient values (r
2) of 0.9982, 0.9973, and 0.9986 for atorvastatin, irbesartan, and amlodipine, respectively. The limits of detection were 0.05, 0.06, and 0.08 µg/mL for the three compounds, respectively. No interference was observed with the detection of the compounds in presence of degradable products; hence, it is confirmed that the analysis is stability‐indicating.
A Theoretical Analysis of the Excited State of Oligoacene Aggregates: Local Excitation vs. Charge‐Transfer Transition
Authors: Kim Dongwook
Published: August 2015

A new approach to evaluate quantitatively the weights of local excitation (LE) and charge‐transfer (CT) transition in the excited state of molecular aggregates has been proposed. It can be achieved by the combination of the molecular orbital fragmentation and natural transition orbital analysis. Armed with this method, we investigated the singlet excited state of acene molecules for representative dimer configurations, i.e., face‐to‐face and herringbone configurations of anthracene, tetracene, and pentacene at scaled opposite spin (SOS)–configuration interaction single (CIS(D)) level of theory. In the case of the face‐to‐face configuration, we found excited state wavefunctions significantly delocalized, giving rise to equal contributions from LE and CT. In the herringbone configuration, however, we found CT character of the excited state marginal. It turned out, however, that, when dimers get closer via intermolecular stretching vibration, CT admixture can be enhanced. Furthermore, in the case of heptamer, CT admixture was substantially magnified, consisting with previous report by Spano and coworkers (J. Chem. Phys. 2011, 134, 204703). Hence, the excited states of molecular aggregates can be quantum chemically analyzed via our approach and important insights into them can be obtained.
Effect of Temperature and Chloride Concentration on the Anodic Formation of Nanoporous Gold Films in Chloride Solutions
Authors: Kim Minju , Jeong Hwakyeung , Lee Euna , Kim Jongwon
Published: August 2015

The preparation of nanoporous gold (NPG) has been the subject of extensive research, and the anodization of Au in chloride solutions has received recent attention as an efficient and time‐saving method. In the present work, the effects of reaction temperature and Cl– concentration on the anodic formation of NPG structures were investigated. The anodization efficiency was evaluated in terms of the roughness factor (R
f) of NPG layers, which varied as a function of these two reaction parameters. The R
f of NPG gradually increased with temperature up to 40 °C and then leveled off at higher temperatures. In terms of Cl– concentration, 1.0 M yielded the maximum R
f of the NPG. The dependence of the anodization efficiency on the two reaction parameters was examined with regard to the electrochemical dissolution of Au as well as the formation of Au–Cl complexes and protective surface oxide layers. The mechanistic aspects of the anodic formation of NPG give insight into the efficient preparation of highly porous NPG structures.
Topology‐aware moving least square deformation for 2D characters
Authors: Wang Xun , Yang Wenwu , Kou Wangbin , Yang Bailin , Wang Guozheng
Published: August 2015

Deformation method based on moving least squares (MLS) allows the user to manipulate 2D characters using either sets of points or line segments in real time. However, the traditional MLS deformation spreads the deformation of the controls with respect to the spatial distance, but oblivious to the shape topology, which would possibly lead to distortion. In this paper, we present a topology‐aware MLS deformation approach for 2D characters. First, a Laplace equation is solved to obtain a set of weights, which are called harmonic weights. Then, the MLS deformation is performed by using the harmonic weights as the deformation influence of the user‐specified controls. Finally, the possible distortion in the traditional MLS deformation can be effectively avoided, as the harmonic weights spread the deformation of the controls in a localized and topology‐aware way. In addition, a simple but effective area‐preserving variant of MLS deformation is proposed, which is suitable for the editing of incompressible objects. Copyright © 2015 John Wiley & Sons, Ltd.
Superior vena cava syndrome with retropharyngeal edema as a complication of ventriculoatrial shunt
Authors: Al‐Natour Mohammed S. , Entezami Pouya , Nazzal Munier M. S. , Casabianca Andrew B. , Assaly Ragheb , Riley Kalen , Gaudin Daniel
Published: August 2015

Key Clinical Message

Thirty‐seven‐year old female with hydrocephalus managed by a ventriculoatrial (VA) shunt presented with upper body edema, dysphagia, and headache. Imaging demonstrated thrombosis of the superior vena cava (SVC). Direct catheter thrombolysis led to resolution of thrombus burden. Superior vena cava thrombosis is a rare consequence of VA shunting and must be managed emergently.
A Modular Synthesis of Conformationally Preorganised Extended β‐Strand Peptidomimetics
Authors: Yamashita Tohru , Knipe Peter C. , Busschaert Nathalie , Thompson Sam , Hamilton Andrew D.
Published: August 2015

A promising strategy for mediating protein–protein interactions is the use of non‐peptidic mimics of secondary structural protein elements, such as the α‐helix. Recent work has expanded the scope of this approach by providing proof‐of‐principle scaffolds that are conformationally biased to mimic the projection of side‐chains from one face of another common secondary structural element—the β‐strand. Herein, we present a synthetic route that has key advantages over previous work: monomers bearing an amino acid side‐chain were pre‐formed before rapid assembly to peptidomimetics through a modular, iterative strategy. The resultant oligomers of alternating pyridyl and six‐membered cyclic ureas accurately reproduce a recognition domain of several amino acid residues of a β‐strand, demonstrated herein by mimicry of the i, i+2, i+4 and i+6 residues.
Recognizing clonorchiasis: A foodborne illness leading to significant hepatobiliary disease
Authors: Gowda Charitha
Published: August 2015

Watch a video presentation of this article

Watch the interview with the author

Answer questions and earn CME
Hepatosplenic candidiasis
Authors: Cornely Oliver A. , Bangard Christopher , Jaspers Natalie I.
Published: August 2015

Watch a video presentation of this article

Watch the interview with the author

Answer questions and earn CME
Issues in the end‐stage liver disease patient for which palliative care could be helpful
Authors: Cox‐North Paula
Published: August 2015

Watch a video presentation of this article

Watch the interview with the author
Working with palliative care services
Authors: Brisebois Amanda J. , Tandon Puneeta
Published: August 2015

Watch a video presentation of this article

Watch the interview with the author
Clinical impact of selective and nonselective beta‐blockers on survival in patients with ovarian cancer
Authors: Watkins Jack L. , Thaker Premal H. , Nick Alpa M. , Ramondetta Lois M. , Kumar Sanjeev , Urbauer Diana L. , Matsuo Koji , Squires Kathryn C. , Coleman Robert L. , Lutgendorf Susan K. , Ramirez Pedro T. , Sood Anil K.
Published: August 2015

BACKGROUND

Preclinical evidence has suggested that sustained adrenergic activation can promote ovarian cancer growth and metastasis. The authors examined the impact of beta‐adrenergic blockade on the clinical outcome of women with epithelial ovarian, primary peritoneal, or fallopian tube cancers (collectively, epithelial ovarian cancer [EOC]).

METHODS

A multicenter review of 1425 women with histopathologically confirmed EOC was performed. Comparisons were made between patients with documented beta‐blocker use during chemotherapy and those without beta‐blocker use.

RESULTS

The median age of patients in the current study was 63 years (range, 21‐93 years). The sample included 269 patients who received beta‐blockers. Of those, 193 (71.7%) were receiving beta‐1–adrenergic receptor selective agents, and the remaining patients were receiving nonselective beta antagonists. The primary indication for beta‐blocker use was hypertension but also included arrhythmia and postmyocardial infarction management. For patients receiving any beta‐blocker, the median overall survival (OS) was 47.8 months versus 42 months for nonusers (P=.04). The median OS based on beta‐blocker receptor selectivity was 94.9 months for those receiving nonselective beta‐blockers versus 38 months for those receiving beta‐1–adrenergic receptor selective agents (P<.001). Hypertension was associated with decreased OS compared with no hypertension across all groups. However, even among patients with hypertension, a longer median OS was observed among users of a nonselective beta‐blocker compared with nonusers (38.2 months vs 90 months;P<.001).

CONCLUSIONS

Use of nonselective beta‐blockers in patients with EOC was associated with longer OS. These findings may have implications for new therapeutic approaches.Cancer2015;121:3435–43.©2015 American Cancer Society.
Experimental Signature of Microheterogeneity in Ionic Liquid–H2O Systems and Their Perturbation by Adding Li+ Salts: A Pulsed Gradient Spin‐Echo NMR Approach
Authors: Nanda Raju , Rajamohanan P. R. , Kumar Anil
Published: August 2015

Distinct microheterogeneity has been observed in the [OMIM]Br–H2O system, which is interestingly perturbed by the addition of Li+ salts, indicating unusual diffusivity of [OMIM]Br and H2O molecules. However, the diffusional dynamics of water clusters show contrasting salting behavior at higher concentrations of Li+ salts, following the classical salting phenomenon in lower amounts. In contrast, the existing microheterogeneity in the [BMIM]Br–H2O system is weak enough to show any perturbation caused by the Li+ salts on the NMR time scale.
Healthcare transition challenges faced by young adults with autism spectrum disorder
Authors: Hall T , Kriz D , Duvall S , Nguyen‐Driver M , Duffield T
Published: August 2015

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that impacts communicative interactions, with patterns of repetitive and restricted behaviors, interests, and cognitive rigidity. Recent incidence rate estimates for ASD are 1 in 68, and primarily male (4:1). A major epidemiological issue in ASD is transitioning to independence in adulthood, particularly navigating the healthcare system. This commentary will focus on approaches healthcare providers can use to not overlook and support individuals with ASD.
Evaluate intellectual property policy for industry‐funded research
Authors: Hope Joan
Published: August 2015

Industry‐funded research can give your professors and students opportunities to solve real‐world problems. But creating agreements that manage intellectual property that comes out of that research can be time‐consuming.
Write the perfect graduation speech
Authors: Hodges Dawn Z.
Published: August 2015

As deans, provosts and other college administrators, we're often called upon to give graduation, pinning, honor society and civic organization speeches. I know I get requests several times a year. I don't have a stash of perfect speeches; I write a new one for every occasion. I like to tailor it to the event, the times, and how I'm feeling at the moment.
Transient optogenetic inactivation of the medial entorhinal cortex biases the active population of hippocampal neurons
Authors: Rueckemann Jon W. , DiMauro Audrey J. , Rangel Lara M. , Han Xue , Boyden Edward S. , Eichenbaum Howard
Published: August 2015

The mechanisms that enable the hippocampal network to express the appropriate spatial representation for a particular circumstance are not well understood. Previous studies suggest that the medial entorhinal cortex (MEC) may have a role in reproducibly selecting the hippocampal representation of an environment. To examine how ongoing MEC activity is continually integrated by the hippocampus, we performed transient unilateral optogenetic inactivations of the MEC while simultaneously recording place cell activity in CA1. Inactivation of the MEC caused a partial remapping in the CA1 population without diminishing the degree of spatial tuning across the active cell assembly. These changes remained stable irrespective of intermittent disruption of MEC input, indicating that while MEC input is integrated over long time scales to bias the active population, there are mechanisms for stabilizing the population of active neurons independent of the MEC. We find that MEC inputs to the hippocampus shape its ongoing activity by biasing the participation of the neurons in the active network, thereby influencing how the hippocampus selectively represents information. © 2015 Wiley Periodicals, Inc.
‘Infinity Means it Goes on Forever’: Siblings' Informal Teaching of Mathematics
Authors: Howe Nina , Adrien Emmanuelle , Della Porta Sandra , Peccia Stephanie , Recchia Holly , Osana Helena P. , Ross Hildy
Published: August 2015

Sibling‐directed teaching of mathematical topics during naturalistic home interactions was investigated in 39 middle‐class sibling dyads at two time points. At time 1 (T1), siblings were 2 and 4 years of age, and at time 2 (T2), siblings were 4 and 6 years of age. Intentional sequences of sibling‐directed mathematical teaching were coded for (i) topics (e.g., number), (ii) contexts (e.g., play with materials/toys), and (iii) type of knowledge (conceptual and procedural). Siblings engaged in teaching number, geometry, and measurement at T1 and demonstrated preliminary evidence of teaching of grouping, relations, and operations at T2. Regarding context, at T1, mathematical teaching occurred most frequently during play with materials/toys, while at T2, games with rules were prominent. Teaching of conceptual or procedural knowledge varied over time and by topic and context. Findings are discussed in light of recent work on understanding children's mathematical knowledge as it develops in the informal family context. Copyright © 2015 John Wiley & Sons, Ltd.
Sonographic evaluation for intra‐abdominal hemorrhage after cesarean delivery
Authors: Hoppenot Claire , Tankou Joan , Stair Sabrina , Gossett Dana R.
Published: August 2015

Purpose

To evaluate whether intra‐abdominal hemorrhage is visible on a modified focused assessment with sonography for trauma (FAST) examination in stable obstetrics patients after a nonemergent cesarean delivery.

Methods

This was a prospective observational study of patients who underwent nonemergent cesarean delivery at a single institution. Patients provided written informed consent to participate in the study preoperatively and underwent a modified FAST examination in the recovery room within 2 hours of completion of surgery. A sonographic examination was considered positive for hemorrhage if an anechoic pocket consistent with free fluid was present.

Results

One hundred patients underwent suprapubic and bilateral upper‐quadrant sonographic evaluations. The mean (±SD) time of the evaluation was 74.2 ± 36 minutes after the end of surgery. Among the 100 sonographic examinations of each upper quadrant, 194 (97.0%) were negative, 5 (2.5%) were indeterminate, and 1 (0.5%) was positive for fluid. All suprapubic sonographic examinations were considered inadequate.

Conclusions

Sonographic evaluation immediately after cesarean delivery is feasible in most patients and was overwhelmingly negative for intra‐abdominal hemorrhage in a group of patients who did not require reoperation or unexpected blood transfusion. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 44:240–244, 2016
Interval Minors of Complete Bipartite Graphs
Authors: Mohar Bojan , Rafiey Arash , Tayfeh‐Rezaie Behruz , Wu Hehui
Published: August 2015

Interval minors of bipartite graphs were recently introduced by Jacob Fox in the study of Stanley–Wilf limits. We investigate the maximum number of edges in ‐interval minor‐free bipartite graphs. We determine exact values when and describe the extremal graphs. For , lower and upper bounds are given and the structure of ‐interval minor‐free graphs is studied.
Neural stem/progenitor cell‐laden microfibers promote transplant survival in a mouse transected spinal cord injury model
Authors: Sugai Keiko , Nishimura Soraya , Kato‐Negishi Midori , Onoe Hiroaki , Iwanaga Shintaroh , Toyama Yoshiaki , Matsumoto Morio , Takeuchi Shoji , Okano Hideyuki , Nakamura Masaya
Published: August 2015

Previous studies have demonstrated that transplantation of neural stem/progenitor cells (NS/PCs) into the lesioned spinal cord can promote functional recovery following incomplete spinal cord injury (SCI) in animal models. However, this strategy is insufficient following complete SCI because of the gap at the lesion epicenter. To obtain functional recovery in a mouse model of complete SCI, this study uses a novel collagen‐based microfiber as a scaffold for engrafted NS/PCs. We hypothesized that the NS/PC–microfiber combination would facilitate lesion closure as well as transplant survival in the transected spinal cord. NS/PCs were seeded inside the novel microfibers, where they maintained their capacity to differentiate and proliferate. After transplantation, the stumps of the transected spinal cord were successfully bridged by the NS/PC‐laden microfibers. Moreover, the transplanted cells migrated into the host spinal cord and differentiated into three neural lineages (astrocytes, neurons, and oligodendrocytes). However, the NS/PC‐laden scaffold could not achieve a neural connection between the rostral end of the injury and the intact caudal area of the spinal cord, nor could it achieve recovery of motor function. To obtain optimal functional recovery, a microfiber design with a modified composition may be useful. Furthermore, combinatorial therapy with rehabilitation and/or medications should also be considered for practical success of biomaterial/cell transplantation‐based approaches to regenerative medicine. © 2015 Wiley Periodicals, Inc.
Experimental Study of the Reactions of OH Radicals with Propane,n‐Pentane, andn‐Heptane over a Wide Temperature Range
Authors: Morin Julien , Romanias Manolis N. , Bedjanian Yuri
Published: August 2015

The kinetics of the reactions of propane,n‐pentane, andn‐heptane with OH radicals has been studied using a low‐pressure flow tube reactor (P = 1 Torr) coupled with a quadrupole mass spectrometer. The rate constants of the title reactions were determined under pseudo–first‐order conditions, monitoring the kinetics of OH radical consumption in excess of the alkanes. A newly developed high‐temperature flow reactor was validated by the study of the OH + propane reaction, where the reaction rate constant,k1 = 5.1 × 10−17T1.85exp(–160/T) cm3molecule−1s−1(uncertainty of 20%), measured in a wide temperature range, 230–898 K, was found to be in excellent agreement with previous studies and current recommendations. The experimental data for the rate constants of the reactions of OH withn‐pentane andn‐heptane can be represented as three parameter expressions (in cm3molecule−1s−1, uncertainty of 20%):k2 = 5.8 × 10−18T2.2exp(260/T) atT= 248–900 K andk3 = 2.7 × 10−16T1.7exp(138/T) atT= 248–896 K, respectively. A combination of the present data with those from previous studies leads to the following expressions:k1 = 2.64 × 10−17T1.93exp(–114/T),k2 = 9.0 × 10−17T1.8exp(120/T), andk3 = 3.75 × 10−16T1.65exp(101/T) cm3molecule−1s−1, which can be recommended fork1,k2, andk3(with uncertainty of 20%) in the temperature ranges 190–1300, 240–1300, and 220–1300 K, respectively.
Kinetic and Mechanisms of the Homogeneous, Unimolecular Elimination of Phenyl Chloroformate andp‐Tolyl Chloroformate in the Gas Phase
Authors: Lezama Jesus , Chuchani Gabriel
Published: August 2015

The gas‐phase elimination of phenyl chloroformate gives chlorobenzene, 2‐chlorophenol, CO2, and CO, whereasp‐tolyl chloroformate producesp‐chlorotoluene and 2‐chloro‐4‐methylphenol CO2and CO. The kinetic determination of phenyl chloroformate (440–480oC, 60–110 Torr) andp‐tolyl chloroformate (430–480°C, 60–137 Torr) carried out in a deactivated static vessel, with the free radical inhibitor toluene always present, is homogeneous, unimolecular and follows a first‐order rate law. The rate coefficient is expressed by the following Arrhenius equations:

Phenyl chloroformate:

Formation of chlorobenzene, logkI= (14.85 ± 0.38)–(260.4 ± 5.4) kJ mol−1(2.303RT)−1;r= 0.9993

Formation of 2‐chlorophenol, logkII= (12.76 ± 0.40) – (237.4 ± 5.6) kJ mol−1(2.303RT)−1;r= 0.9993

p‐Tolyl chloroformate:

Formation ofp‐chlorotoluene: logkI= (14.35 ± 0.28) – (252.0 ± 1.5) kJ mol–1(2.303RT)−1;r= 0.9993

Formation of 2‐chloro‐4‐methylphenol, logkII= (12.81 ± 0.16) – (222.2 ± 0.9) kJ mol−1(2.303RT)–1;r= 0.9995

The estimation of thekIvalues, which is the decarboxylation process in both substrates, suggests a mechanism involving an intramolecular nucleophilic displacement of the chlorine atom through a semipolar, concerted four‐membered cyclic transition state structure; whereas thekIIvalues, the decarbonylation in both substrates, imply an unusual migration of the chlorine atom to the aromatic ring through a semipolar, concerted five‐membered cyclic transition state type of mechanism. The bond polarization of the C–Cl, in the sense Cδ+…Clδ−, appears to be the rate‐determining step of these elimination reactions.
Land Use Effects on Mangrove Nutrient Status in Phang Nga Bay, Thailand
Authors: Wolters Jan‐Willem , Gillis Lucy G. , Bouma Tjeerd J. , van Katwijk Marieke M. , Ziegler Alan D.
Published: August 2015

Tropical mangrove forests can play an important role in the functioning of adjacent marine ecosystems, by protecting them from an excess in land‐derived sediment and nutrients. The strength of this interaction may however depend on the nutrient status of the mangrove forest. This study related the nutrient status of eight mangrove forests in Phang Nga Bay (Thailand) to the land‐cover distributions in the upstream catchment areas. Nutrient status was assessed using indicators integrating over short (porewater and sediment nutrient composition) and long timespans (mangrove leaves and sesarmid crab tissue characteristics). Using multivariate statistics (PCA analysis), these nutrient status data were then related to the land cover data, which were obtained through the analysis of satellite imagery. Nutrient availability was lowest for mangroves in catchments with large natural vegetation cover and was elevated in catchments with increasing levels of anthropogenic influence. Furthermore, nutrient availability was significantly correlated with several forms of land use, including natural forest, rice paddies, cleared ground and urban areas. While all indicators supported these results, relationships were strongest for long‐term indicators. Information on the relationship between land use in the catchment area and mangrove nutrient status may be important for the effective management of this habitat, as well as adjacent marine systems. Copyright © 2015 John Wiley & Sons, Ltd.
Therapeutic advances in dystonia
Authors: Albanese Alberto , Romito Luigi M. , Calandrella Daniela
Published: August 2015

Knowledge on dystonia has greatly improved recently, because of a renewed effort in understanding its cause, pathophysiology, and clinical characterization. Different drug classes traditionally have been used for the symptomatic treatment of dystonia, more recently surpassed by the introduction of botulinum neurotoxins and deep brain stimulation. No curative or disease‐modifying treatments are available. Recent knowledge regarding the pathophysiology of inherited dystonias is highlighting new potential treatment strategies. We review therapeutic advances in dystonia that have been published over the last 3 years, particularly regarding oral medications, local injections of botulinum neurotoxins, deep brain stimulation, and transcranial or epidural brain stimulations. We discuss evidence of efficacy, highlight recent advances, and focus on key areas under development. © 2015 International Parkinson and Movement Disorder Society
Functional electron paramagnetic resonance imaging of ischemic rat heart: Monitoring of tissue oxygenation and pH
Authors: Gorodetsky Artem A. , Kirilyuk Igor A. , Khramtsov Valery V. , Komarov Denis A.
Published: August 2015

Purpose

Electron paramagnetic resonance (EPR) imaging in the spectral‐spatial domain with application of soluble paramagnetic probes provides an opportunity for spatially resolved functional measurements of living objects. The purpose of this study was to develop EPR methods for visualization of oxygenation and acidosis of ischemic myocardium.

Methods

EPR oxygen measurements were performed using isotopically substituted 2H,15N‐dicarboxyproxyl. The radical has an EPR line width of 320 mG and oxygen‐induced line broadening of 0.53 mG/mm Hg, providing oxygen sensitivity down to 5 μM. pH measurements were performed using previously developed pH‐sensitive imidazoline nitroxide. The radical has an EPR spectrum with pH‐dependable hyperfine splitting, pK = 6.6, providing pH sensitivity of approximately 0.05 U in the physiological range.

Results

EPR imaging of isolated and perfused rat hearts was performed in the two‐dimensional + spectral domain. The spatial resolution of the measurements was about 1.4 mm. Marked tissue hypoxia was observed in the ischemic area of the heart after occlusion of the left anterior descending coronary artery. Tissue oxygenation was partly restored upon reperfusion. EPR mapping of myocardial pH indicated acidosis of the ischemic area down to pH 6.7–6.8.

Conclusion

This study demonstrates the capability of low‐field EPR and the nitroxide spin probes for mapping of myocardial oxygenation and pH. The developed approaches might be used for noninvasive investigation of microenvironment on living objects. Magn Reson Med 76:350–358, 2016. © 2015 Wiley Periodicals, Inc.
Simultaneous quantitative mapping of conductivity and susceptibility using a double‐echo ultrashort echo time sequence: Example using a hematoma evolution study
Authors: Gho Sung‐Min , Shin Jaewook , Kim Min‐Oh , Kim Dong‐Hyun
Published: August 2015

Purpose

The primary purpose of this study is to propose a method for the simultaneous quantitative three‐dimensional (3D) mapping of conductivity and susceptibility using double‐echo ultrashort echo time (UTE) imaging. The secondary purpose is to investigate the changes of these properties over time during in vitro hematoma evolution in blood samples.

Methods

The first and second set of echo data for a UTE sequence were used to perform quantitative conductivity mapping (QCM) and quantitative susceptibility mapping (QSM), respectively. A simulation study was conducted to determine the echo time (TE) range that was acceptable for QCM. Subsequently, a NaCl phantom experiment and in vivo 3D QCM and QSM demonstrations were performed. The changes in electromagnetic (EM) properties over time were studied using in vitro blood coagulation experiments with venous blood from healthy volunteers.

Results

Quantitative and qualitative analyses showed small differences in the QCM for TE values up to 300 μs. The estimated conductivity and susceptibility values monotonically increased during the first few hours of the hematoma evolution experiments. However, although the susceptibility values continued to increase, the conductivity values were steady after 24 h.

Conclusion

The proposed method can be useful for determining EM property changes (including those during hemorrhage) and providing additional information about the state of the blood. Magn Reson Med 76:214–221, 2016. © 2015 Wiley Periodicals, Inc.
Acquisition of 3D temperature distributions in fluid flow using proton resonance frequency thermometry
Authors: Buchenberg Waltraud B. , Wassermann Florian , Grundmann Sven , Jung Bernd , Simpson Robin
Published: August 2015

Purpose

Proton resonance frequency thermometry is well established for monitoring small temperature changes in tissue. Application of the technique to the measurement of complex temperature distributions within fluid flow is of great interest to the engineering community and could also have medical applications. This work presents an experimental approach to reliably measure three‐dimensional (3D) temperature fields in fluid flow using proton resonance frequency thermometry.

Methods

A velocity‐compensated three‐dimensional gradient echo sequence was used. A flexible pumping system was attached to an MR compatible double pipe heat exchanger. The temperature of two separate flow circuits could be adjusted to produce various three‐dimensional spatial temperature distributions within the fluid flow. Validation was performed using MR compatible temperature probes in a uniformly heated flow. A comparative study was conducted with thermocouples in the presence of a spatially varying temperature distribution.

Results

In uniformly heated flow, temperature changes were accurately measured to within 0.5 K using proton resonance frequency thermometry, while spatially varying temperature changes measured with MR showed good qualitative agreement with pointwise measurements using thermocouples.

Conclusion

Proton resonance frequency thermometry can be used in a variety of complex flow situations to address medical as well as engineering questions. This work makes it possible to gain new insights into fundamental heat transfer phenomena. Magn Reson Med 76:145–155, 2016. © 2015 Wiley Periodicals, Inc.
High‐resolution mapping of neuronal activation with balanced SSFP at 9.4 tesla
Authors: Scheffler Klaus , Ehses Philipp
Published: August 2015

Purpose

This work investigates the feasibility of high‐resolution functional imaging of the human brain using passband balanced steady state free precession (SSFP) at 9.4 Tesla (T). To this end, the temporal signal stability, blood‐oxygen‐level‐dependent (BOLD)‐related signal changes and sensitivity to frequency offsets were evaluated.

Methods

Three‐dimensional slab selective and nonselective balanced SSFP have been implemented with minimized repetition time and high temporal resolution using parallel imaging, partial Fourier acquisition and elliptical scanning. Using a volume repetition time of approximately 3 s, a visual checker board stimulation was applied for 6 min. Temporal signal stability of balanced SSFP and BOLD response‐related signal changes and sensitivity to frequency changes were evaluated.

Results

Activation could be detected in all volunteers with BOLD‐related signal changes from 3% to 6%. At 1 mm isotropic resolution, the thermal noise SNR0 was 67 and the total temporal noise variation tSNR was 45 supporting a very high signal stability of balanced SSFP. No significant changes of activation at different offresonance frequencies were detected.

Conclusion

High spatial and temporal resolution balanced SSFP at 9.4T to detect functional activation is feasible. Activation patterns and signal changes are stable and reproducible across subjects within the visual cortex, and comparable to reported values of SE‐EPI at 7T and 9.4T. Magn Reson Med 76:163–171, 2016. © 2015 Wiley Periodicals, Inc.
Designing syntheses of cellulose and starch derivatives with basic or cationic N‐functions: part I—cellulose derivatives
Authors: Salimi Hamid , Aryanasab Fezzeh , Banazadeh Ali Reza , Shabanian Meisam , Seidi Farzad
Published: August 2015

The use of cellulose and starch derivatives that bear amino or quaternary ammonium moieties is steadily increasing, and the applications in industry are continuing to grow. These promising products are routinely used in cosmetic and paper‐making industries. This article provides an overview of strategies available to chemists for designing the syntheses of such compounds. The review provides a brief historical perspective on synthesis and describes recent developments that have enabled chemists to enhance their synthesis productivity. However, the graft polymerization techniques are far from the scope of this paper and will be noted in a few words only. In addition to the structural and synthetic aspects, applications of these derivatives are discussed in brief. We have divided this article in two parts mainly because of the vastness of the subject and limited space available. The first part of which reviews the advances in the synthesis of basic and cationic cellulose derivatives having amino or quaternary ammonium moieties and the second part of which considers starch ones. Copyright © 2015 John Wiley & Sons, Ltd.
Seasonal surface urban energy balance and wintertime stability simulated using three land‐surface models in the high‐latitude city Helsinki
Authors: Karsisto P. , Fortelius C. , Demuzere M. , Grimmond C. S. B. , Oleson K. W. , Kouznetsov R. , Masson V. , Järvi L.
Published: August 2015

The performance of three urban land‐surface models, run in off‐line mode, with their default external parameters, is evaluated for two distinctly different sites in Helsinki: Torni and Kumpula. The former is a dense city‐centre site with 22% vegetation, while the latter is a suburban site with over 50% vegetation. At both locations the models are compared against sensible and latent heat fluxes measured using the eddy covariance technique, along with snow depth observations. The cold climate experienced by the city causes strong seasonal variations that include snow cover and stable atmospheric conditions.

Most of the time the three models are able to account for the differences between the study areas as well as the seasonal and diurnal variability of the energy balance components. However, the performances are not systematic across the modelled components, seasons and surface types. The net all‐wave radiation is well simulated, with the greatest uncertainties related to snow‐melt timing, when the fraction of snow cover has a key role, particularly in determining the surface albedo. For the turbulent fluxes, more variation between the models is seen which can partly be explained by the different methods in their calculation and partly by surface parameter values. For the sensible heat flux, simulation of wintertime values was the main problem, which also leads to issues in predicting near‐surface stabilities particularly at the dense city‐centre site. All models have the most difficulties in simulating latent heat flux. This study particularly emphasizes that improvements are needed in the parametrization of anthropogenic heat flux and thermal parameters in winter, snow cover in spring, and evapotranspiration, in order to improve the surface energy balance modelling in cold‐climate cities.
A novel bit scalable leakage model based on genetic algorithm
Authors: Zhang Zhenbin , Wu Liji , Wang An , Mu Zhaoli , Zhang Xiangmin
Published: August 2015

With the growing popularity of smart integrated circuit (IC) cards, the chip security is attracting more and more attention. Researches on the attack and protection of smart IC cards have become increasingly hot. Side‐channel attack is the practical and effective method, which has brought enormous threat. The efficiency of attack depends on the extent of the leakage model, which characterizes the practical applications. In the power analysis attack, the classical leakage model usually exploits the power consumption of single S‐box, which is called divide and conquer. Taking data encryption standard (DES) algorithm, for example, the attack on each S‐box needs to search the key space of 26 in a brute‐force way. In this paper, we propose a novel leakage model, which is more flexible than the classical leakage model. The novel leakage model is based on the power consumption of multiple S‐boxes, and the implementation of this method is combined with genetic algorithm. We can establish leakage model based on the Hamming distance of round output generated by eight S‐boxes in DES algorithm. The experiment verifies the fact that the leakage model of eight S‐boxes can decrease the traces number up to 52% than the classical one based on single S‐box for DES algorithm. It also decreases the traces number up to 32% for SM4 algorithm. All the measurements of power data are acquired from a practical smart IC card. We also conclude that increasing noise, using variable clock, and limiting the lifetime of root key can be the choices of defensive strategy. Copyright © 2015 John Wiley & Sons, Ltd.
Temporal Events and Problem Structuring
Authors: Houghton Luke , Crump Larry
Published: August 2015

Problems come with a history and sometimes an assumed future. Our understanding of the past and our assumptions of the future shape the way we structure problems. In this paper, we explore how the past and the future might influence temporality in problem structuring and identify the utility of linkage theory in providing temporal understanding. Data for this paper are derived from trade treaty negotiations conducted by the USA and Singapore (2000–2003), Australia and Singapore (2000–2003) and Australia and the USA (2003–2004). These three negotiations, occurring concurrently or consecutively in time, allow us to examine a temporal quality to problem‐structuring through linkage theory. This study enriches our understanding of the problem‐structuring methods literature by focusing on how temporal issues play a role in how problems are structured. The negotiation context described earlier is used as an exemplar of how temporal issues affect problem structuring. Our aim is to begin a discussion on how and if a temporal perspective can be handled methodologically. Copyright © 2015 John Wiley & Sons, Ltd.
Assessment of pelvic floor muscle contraction with palpation, perineometry and transperineal ultrasound: a cross‐sectional study
Authors: Volløyhaug I. , Mørkved S. , Salvesen Ø. , Salvesen K. Å.
Published: August 2015

Objective

To study the correlation between palpation, perineometry and transperineal ultrasound for assessment of pelvic floor muscle contraction and to define a contraction scale for ultrasound measurements.

Methods

This was a cross‐sectional study of 608 women examined with palpation of pelvic floor muscle contraction, using the Modified Oxford Scale, and measurement of the vaginal squeeze pressure with a vaginal balloon connected to a fiber‐optic microtip transducer (perineometry). Transperineal ultrasound was used for measurements of levator hiatal area and anteroposterior (AP) diameter in the plane of minimal hiatal dimensions, at rest and on contraction. The pelvic floor muscle contraction was expressed as the percentage difference between values at rest and on contraction. Spearman's rank was used to test for correlation between the different methods of assessment.

Results

Significant correlations were found between all assessment methods (P < 0.001). Palpation correlated with perineometry (rs = 0.74) and with proportional change in hiatal area (rs = 0.67) and AP diameter (rs = 0.69) on ultrasound. Perineometry correlated with proportional change in hiatal area (rs = 0.60) and AP diameter (rs = 0.66) on ultrasound. We defined a contraction scale based on the proportional change in AP diameter. In this population, a change in AP diameter of < 7% corresponded to absence of contractions, 7–18% corresponded to weak contractions, 18–35% corresponded to normal contractions and > 35% corresponded to strong contractions.

Conclusions

We found moderate to strong correlation between ultrasound measurements, palpation and perineometry for assessing pelvic floor muscle contraction. The proportional change in levator hiatal AP diameter was the ultrasound measurement with strongest correlation to palpation and perineometry and formed the basis for the contraction scale for ultrasound measurements. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.