bluuebunny/crossref_metadata_2025 huggingface dataset:
Volumetric stratification of cT4 stage head and neck cancer
Authors: Studer G. , Glanzmann C.
Published: September 2013

Background

Locoregionally advanced stage head and neck cancer (HNC) is known for unfavorable outcome with only ~ 40–50 % 3-year overall survival (OS). Clinical T4 stage includes a wide range of tumor burden. The lack of further nonsurgical subgrouping of cT4 stage makes intercenter outcome of irradiated cohorts difficult. Aim of this analysis was to further stratify cT4 stage HNC using volumetric staging.

Material and methods

Between January 2002 and January 2013, a total of 201 cT4 stage squamous cell cancer (SCC) HNC patients referred to our center for curative definitive radiation were consecutively irradiated. Radiation was performed using modulated techniques. Total gross tumor volumes (tGTV: primary + nodal tumor volume) of all patients have retrospectively been stratified using a prospectively evaluated volumetric staging system which bases on 3 cut-offs (15/70/130 ml), translating into 4 prognostic subgroups [V1: 1–15 ml (n = 15), V2: 16–70 ml (108), V3: 71–130 ml (62), V4: > 130 ml (16)]. OS, disease-free survival (DFS), locoregional control (LRC), and distant metastasis-free survival (DMFS) rates were calculated.

Results

The mean/median follow-up was 31/23 months (range 1–116 months). The 3-year OS, DFS, LRC, and DMFS rates of the entire cohort were 63, 44, 48, and 77 %, respectively. Volumetric staging revealed its potential to prognostically statistically significantly divide the cT4 cohort into 4 volume subgroups (V1/2/3/4): OS: 90 %/72 %/58 %/18 %; DFS: 83 %/50 %/39 %/10 %; LRC: 81 %/53 %/47 %/15 %; DMFS: 93 %/90 %/70 %/41 %, all p < 0.0001.

Conclusion

Volumetric staging allowed a highly statistically significant stratification of cT4 HNC stages into prognostic subgroups, which offers the chance of better intercenter comparability of irradiated advanced stage HNC cohorts.
Various species of Pyricularia constitute a robust clade distinct from Magnaporthe
salvinii and its relatives in Magnaporthaceae
Authors: Murata Nobuaki , Aoki Takayuki , Kusaba Motoaki , Tosa Yukio , Chuma Izumi
Published: September 2013

In a phylogenetic analysis of species of Magnaporthaceae based on nucleotide sequences of rDNA-ITS and the RPB1 gene, isolates of the tested species were divided into two clusters with high bootstrap support. One group was composed of Pyricularia spp.; the other was composed of Magnaporthe salvinii, M. rhizophila, M. poae, Gaeumannomyces graminis, and G. incrustans. On the basis of this result, we concluded that Pyricularia spp. constitute a large but distinct phylogenetic species group that is not congeneric with Magnaporthe salvinii, the type species of Magnaporthe.
Psychosocial predictors and outcomes of loneliness trajectories from childhood to early adolescence☆
Authors: Schinka Katherine C. , van Dulmen Manfred H.M. , Mata Andrea D. , Bossarte Robert , Swahn Monica
Published: September 2013

Using latent class growth analysis, we were interested in investigating how experiences of loneliness emerge in distinct developmental patterns over the course of middle childhood and adolescence (NICHD Study of Early Child Care, N = 832). Second, we examined the role of demographic, mental health, and behavioral variables in association with these discrete patterns of loneliness. Loneliness was measured at 3 time points: age 9, age 11, and age 15. Results indicated five discrete trajectories of loneliness from middle childhood to adolescence. Most children exhibited a stable and low level of loneliness over time. The remaining children were split among moderate increasing, high increasing, decreasing, and chronic loneliness groups. Ethnicity, income, age 7 social skills, age 7 depression, and age 7 aggression were associated with trajectory membership. In addition, the loneliness trajectories predicted self‐reports of social skills deficits, depression, aggression, and suicidal ideation at age 15.
Human chorionic gonadotropin as a measure of pregnancy duration
Authors: Larsen John , Buchanan Philip , Johnson Sarah , Godbert Sonya , Zinaman Michael
Published: September 2013

Objective

To compare gestational age (GA) estimates in early pregnancy, determined by last menstrual period (LMP), human chorionic gonadotropin (hCG) concentration, ultrasound crown–rump length (Hadlock formula), and ovulation day (luteinizing hormone surge plus 1 day).

Methods

Female volunteers seeking to conceive (at 5 US sites) collected daily early‐morning urine for up to 3 menstrual cycles. Pregnant women underwent ultrasound dating scans. Conception cycle urine was quantitatively assessed for luteinizing hormone and hCG. Summary statistics for GA using each reference method were determined (n = 131).

Results

Correlation between GA determined by ultrasound and ovulation day was excellent (maximum difference 10 days); however, pregnancies dated by ultrasound were 3 days advanced. The difference between LMP estimates and estimates based on ovulation day or ultrasound was 9 and 12 days, respectively. A uniform rise in hCG on each day of pregnancy was seen using all reference methods. The accuracy of hCG measurement in determining the week since conception was more than 93%.

Conclusion

Methods for establishing pregnancy duration vary in their accuracy and their GA estimates. The rise in hCG concentration in early pregnancy is uniform and therefore hCG levels provide the most accurate, early estimation of GA in single, viable pregnancies.

ClinicalTrials.gov: NCT01077583
Risk factors for intraoperative hemorrhage at evacuation of a cesarean scar pregnancy following uterine artery embolization
Authors: Wang Jian‐Hua , Qian Zhi‐Da , Zhuang Ya‐Ling , Du Yong‐Jiang , Zhu Lin‐Hua , Huang Li‐Li
Published: September 2013

Objective

To determine risk factors associated with massive uterine bleeding during dilation and suction curettage (D&C) after uterine artery embolization (UAE) for the treatment of cesarean scar pregnancy (CSP).

Methods

Data from 128 CSP patients treated with D&C after UAE were analyzed to assess risk factors associated with massive uterine bleeding (blood loss 500 mL or more) during D&C after UAE.

Results

In total, 15 CSP patients had massive bleeding during D&C after UAE. Univariate analysis showed that a greater gestational age (GA), a larger CSP mass size, a thinner myometrium at the implantation site, a GA of 8 weeks or more, a CSP mass diameter of 6 cm or more, and evidence of fetal heartbeat were risk factors for massive bleeding (P < 0.05). In a binary logistic regression analysis, GA of 8 weeks or more and CSP mass diameter of 6 cm or more remained as the only significant risk factors for massive bleeding (OR 11.49 [95% CI 1.08–122.13] and OR 96.59 [95% CI 6.20–150.57], respectively; P < 0.05).

Conclusion

For CSP masses with a GA of 8 weeks or more and a diameter of 6 cm or more, the outcome of surgical evacuation after UAE tends to be unsatisfactory.
The relationship between facility delivery and infant immunization in Ethiopia
Authors: Moyer Cheryl A. , Tadesse Lia , Fisseha Senait
Published: September 2013

Objective

To determine whether facility delivery is related to compliance with recommended infant immunizations, particularly those that occur weeks or months after delivery.

Methods

In a retrospective analysis, multivariate logistic regression was used to assess data from the 2011 Ethiopia Demographic and Health Survey (EDHS) to determine the strongest correlates of facility delivery. These correlates were then used, along with facility delivery itself, to determine the relationship between facility delivery and infant immunization.

Results

In total, 3334 women delivered a newborn 12–24 months before the 2011 EDHS: 90.2% (3007) delivered at home, and 9.8% (327) delivered in a facility. Education, wealth status, urban residence, and number of children under 5 years living in the household were the factors most strongly associated with facility delivery. When facility delivery and its strongest correlates were entered into multivariate logistic regression models with infant immunizations as the outcome, facility delivery was significantly associated with increased likelihood of DPT‐HepB‐Hib, polio, and measles vaccination, and increased likelihood of being fully immunized (all P < 0.01). Facility delivery was the strongest single factor associated with infants being immunized, doubling the odds of full immunization.

Conclusion

The impact of facility delivery on health outcomes transcends the immediate delivery and postpartum period.
Statistical accuracy of scattered points filters and application to the dynamics of bubbles in gas-fluidized beds
Authors: Acosta-Iborra A. , Sánchez-Delgado S. , Scott S. A. , Müller C. R. , Dennis J. S.
Published: September 2013

A novel analytical equation for the assessment of the accuracy of filters used for the interpolation and differentiation of scattered experimental data is presented. The equation takes into account the statistical nature of the filter output resulting from both the arbitrary positions of the data points and the randomness and noise present in the experimental data. Numerical estimation of the accuracy of the filter, using a Monte Carlo procedure, shows good agreement with the deduced analytical equation. This numerical procedure was also used to determine the accuracy of variance filters aimed at calculating the mean-square fluctuation of experimental data. The combination of the numerical results and analytical equations reveals the exact sources of inaccuracy arising in scattered point filters, namely: (i) the spectral inaccuracy of the weighting function; (ii) the noise or stochastic signal amplification; and (iii) the error arising from the random collocation of points within the filter window. The results also demonstrate that the use of the local mean in the calculation of the quadratic fluctuation leads to smaller estimation errors than the central mean. Finally, all these filters are used and critically evaluated in the framework of the stochastic position, diameter, and velocity of bubbles in a gas-fluidized bed. It is shown that the empirical coefficient of bubble coalescence in the two-dimensional bed tested, $\bar {\lambda } $, is in the range 2.0–2.4 when incorporating only the visible flow of bubbles. Here, the vertical distance over which a bubble survives without coalescing is $\bar {\lambda } {L}_{c} $, where ${L}_{c} $ is the characteristic separation between neighbouring bubbles in the horizontal direction prior to coalescence. It was also seen that the relative mean-square-root fluctuation of both bubble diameter and velocity is more than 50 % at the centre of the bed and remains nearly constant along the height of the bed.
Effect of fatty acid chain length and saturation on the gastrointestinal handling and metabolic disposal of dietary fatty acids in women
Authors: Jones Amanda E. , Stolinski Michael , Smith Ruth D. , Murphy Jane L. , Wootton Stephen A.
Published: September 2013

The gastrointestinal handling and metabolic disposal of [1-13C]palmitic acid, [1-13C]stearic acid and [1-13C]oleic acid administered within a lipid–casein–glucose–sucrose emulsion were examined in normal healthy women by determining both the amount and nature of the13C label in stool and label excreted on breath as13CO2. The greatest excretion of13C label in stool was in the stearic acid trial (9.2 % of administered dose) whilst comparatively little label was observed in stool in either the palmitic acid (1.2 % of administered dose) or oleic acid (1.9 % of administered dose) trials. In both the palmitic acid and oleic acid trials, all of the label in stool was identified as being present in the form in which it was administered (i.e. [13C]palmitic acid in the palmitic acid trial and [13C]oleic acid in the oleic acid trial). In contrast, only 87 % of the label in the stool in the stearic acid trial was identified as [13C]stearic acid, the remainder was identified as [13C]palmitic acid which may reflect chain shortening of [1-13C]stearic acid within the gastrointestinal tract. Small, but statistically significant, differences were observed in the time course of recovery of13C label on breath over the initial 9 h of the study period (oleic acid = palmitic acid > stearic acid). However, when calculated over the 24 h study period, the recovery of the label as13CO2was similar in all three trials (approximately 25 % of absorbed dose). These results support the view that chain length and degree of unsaturation may influence the gastrointestinal handling and immediate metabolic disposal of these fatty acids even when presented within an emulsion.
The African Origins of the Amistad Rebellion, 1839
Authors: Rediker Marcus
Published: September 2013

This essay explores the Amistad rebellion of 1839, in which fifty-three Africans seized a slave schooner, sailed it to Long Island, New York, made an alliance with American abolitionists, and won their freedom in a protracted legal battle. Asking how and why the rebels succeeded, it emphasizes the African background and experience, as well as the “fictive kinship” that grew out of many incarcerations, as sources of solidarity that made the uprising possible. The essay concludes by discussing the process of mutiny, suggesting a six-phase model for understanding the dynamics of shipboard revolt, and showing how such events can have powerful historical consequences.
International Radicalism, Local Solidarities: The 1797 British Naval Mutinies in Southern African Waters
Authors: Ulrich Nicole
Published: September 2013

This article details the 1797 mutinies in the British Royal Navy in southern African waters at Simon's Bay and Table Bay at the Cape of Good Hope. Drawing attention to the intersections between international protest during the age of revolution and between local, African protest, it shows that the Cape mutinies were part of an empire-wide strike, and were rooted in the organizational traditions of naval sailors. Yet, these mutinies were also of local significance. They signalled the growing confidence, and radicalization, of the popular classes at the Cape, as sailors, KhoiSan labourers, and slaves all experimented with new strategies of rebellion. Realizing the fundamental class bias of custom and law during their struggles for improvements in wages and working conditions and for a more democratic workplace regime, naval sailors also contributed to a broader political dialogue at the Cape concerning the relationship between the imperial state, freedom, and rights.
The Place of theGospel of Philipin the Context of Early Christian Claims about Jesus' Marital Status
Authors: King Karen L.
Published: September 2013

It has long been recognized that one of the main topics of theGospel of Philipis ritual, including ‘the bridal chamber’, and numerous studies have discussed what practices and attitudes toward sexuality and marriage are implied by this imagery. This article will build on these studies to argue that theGospel of Philipportrays the incarnate Jesus as actually married (to Mary Magdalene) and it represents that marriage as a symbolic paradigm for the reunification of believers with their angelic (spiritual) doubles in Christian initiation ritual, a ritual which effectively transforms initiates into members of the body of Christ and also enables ‘undefiled marriage’ for Christian partners by freeing them from demonic influences. The article aims to show that this distinctive position on Jesus' marital status was catalyzed by reading Ephesians 5 in conjunction with Valentinian incarnational theology.
Effect of medication-related factors on adherence in people with schizophrenia: A European multi-centre study
Authors: Meier Johanna , Becker Thomas , Patel Anita , Robson Debbie , Schene Aart , Kikkert Martijn , Barbui Corrado , Burti Lorenzo , Puschner Bernd
Published: September 2013

Aim– To investigate the relation between medication-related factors and adherence in people with schizophrenia in outpatient treatment.Methods– The sample comprised 409 outpatients (ICD-10 diagnosis of schizophrenia) with clinician-rated instability in four European cities (Amsterdam, The Netherlands; Verona, Italy; Leipzig, Germany; London, Great Britain). Adherence was assessed using theMedication Adherence Questionnaire(patient perspective), and theClinician Rating Scale(clinician perspective). Examined medication-related factors were type (atypical vs. typical), application (oral vs. depot), daily dose frequency of antipsychotic medication (Medication History Scale), number of side effects (Liverpool University Neuroleptic Side Effect Rating Scale), and patient attitudes toward medication (Drug Attitude Inventory). Multiple regression analysis was used to identify predictors of adherence by medication-related factors.Results– Adherence, as rated by patient and clinician, was predicted by patient attitude towards medication, but was unrelated to type of drug, formulation or side effects of antipsychotic medication. A high daily dose frequency was associated with better adherence, but only when rated by the patient.Conclusions– In order to improve adherence there is a need to seriously consider and attempt to improve patient attitude toward medication. However, type of antipsychotic and other medication-related factors may not be as closely related to adherence as it has often been suggested.

Declaration of Interest:The study was funded by a grant from the Quality of Life and Management of Living Resources Program of the European Union (QLG4-CT-2001–01734). JM, AS, CB, MK, CB, LB, and BP declare that they have not received any form of financing including pharmaceutical company support or any honoraria for consultancies or interventions during the last two years. DR has received honoraria from Eli Lilly, Janssen Cilag and Astra Zeneca for consultancy work, and Anita Patel has received research consultancy funding from Servier. TB reports research funding to the department from Astra Zeneca, GlaxoSmithKline and Affectis for clinical trials and investigator-initiated trials; the department has also received funds to a minor extent for symposia and in-house training from Astra Zeneca, Bristol-Myers Squibb, Eisai, Janssen Cilag, Lilly Germany, Lundbeck, Novartis, Pfizer, Servier, and Wyeth. All authors declare that they have no other involvements that might be considered a conflict of interest in connection with this article.
Seeded strain‐like transmission of β‐amyloid morphotypes in APP transgenic mice
Authors: Heilbronner Götz , Eisele Yvonne S , Langer Franziska , Kaeser Stephan A , Novotny Renata , Nagarathinam Amudha , Åslund Andreas , Hammarström Per , Nilsson K Peter R , Jucker Mathias
Published: September 2013

The polymorphic β‐amyloid lesions present in individuals with Alzheimer's disease are collectively known as cerebral β‐amyloidosis. Amyloid precursor protein (APP) transgenic mouse models similarly develop β‐amyloid depositions that differ in morphology, binding of amyloid conformation‐sensitive dyes, and Aβ40/Aβ42 peptide ratio. To determine the nature of such β‐amyloid morphotypes, β‐amyloid‐containing brain extracts from either aged APP23 brains or aged APPPS1 brains were intracerebrally injected into the hippocampus of young APP23 or APPPS1 transgenic mice. APPPS1 brain extract injected into young APP23 mice induced β‐amyloid deposition with the morphological, conformational, and Aβ40/Aβ42 ratio characteristics of β‐amyloid deposits in aged APPPS1 mice, whereas APP23 brain extract injected into young APP23 mice induced β‐amyloid deposits with the characteristics of β‐amyloid deposits in aged APP23 mice. Injecting the two extracts into the APPPS1 host revealed a similar difference between the induced β‐amyloid deposits, although less prominent, and the induced deposits were similar to the β‐amyloid deposits found in aged APPPS1 hosts. These results indicate that the molecular composition and conformation of aggregated Aβ in APP transgenic mice can be maintained by seeded conversion.
Depletion of serotonin in the basolateral amygdala elevates glutamate receptors and facilitates fear-potentiated startle
Authors: Tran L , Lasher B K , Young K A , Keele N B
Published: September 2013

Our previous experiments demonstrated that systemic depletion of serotonin (5-hydroxytryptamine, 5-HT), similar to levels reported in patients with emotional disorders, enhanced glutamateric activity in the lateral nucleus of the amygdala (LA) and potentiated fear behaviors. However, the effects of isolated depletion of 5-HT in the LA, and the molecular mechanisms underlying enhanced glutamatergic activity are unknown. In the present study, we tested the hypothesis that depletion of 5-HT in the LA induces increased fear behavior, and concomitantly enhances glutamate receptor (GluR) expression. Bilateral infusions of 5,7-dihydroxytryptamine (4 μg per side) into the LA produced a regional reduction of serotonergic fibers, resulting in decreased 5-HT concentrations. The induction of low 5-HT in the LA elevated fear-potentiated startle, with a parallel increase in GluR1 mRNA and GluR1 protein expression. These findings suggest that low 5-HT concentrations in the LA may facilitate fear behavior through enhanced GluR-mediated mechanisms. Moreover, our data support a relationship between 5-HT and glutamate in psychopathologies.
Analysis of collaborative spectrum sensing without dedicated sensing period
Authors: Chen Yunfei , Tang Liang , Long Min
Published: September 2013

Previous works on spectrum sensing use either samples free of secondary user interference based on dedicated sensing period or samples with partly ‘cleaned’ secondary user interference based on specific characteristics of orthogonal frequency division multiplexing signals or decoded signals. In this article, collaborative spectrum sensing using samples corrupted by secondary user interference without dedicated sensing period or ‘cleaning’ procedure is studied, and its performance is analysed. Two different cases of primary user signals are considered. In the first case, the primary user signal suffers from fast fading, whereas in the second case, the primary user signal suffers from slow fading. New detectors for these two cases are derived, based on which their performances are analysed. Numerical results show that the diversity gain is lost because of the secondary user interference. For fast‐fading primary user signal, the sensing performance deteriorates quickly when the number of interfering secondary users increases, whereas for slowly fading primary user signal, an error floor exists when the number of interfering secondary users increases. On the other hand, by choosing appropriate system parameters, high sensing accuracy can still be achieved with acceptable loss in detection probability, but with long transmission time when no dedicated sensing period or ‘cleaning’ procedure are used.
New algorithm for the protection of delta‐hexagonal phase shifting transformer
Authors: Khan Umar , Sidhu Tarlochan S.
Published: September 2013

Delta/hexagonal phase shifting transformer (PST) represents both magnetically coupled and electrically connected circuits, which makes it unique in design and construction from a standard transformer. Conventionally, differential protection serves as a main protection element of PST and offers distinguished features such as speed and selectivity. On the contrary, it is prone to various new challenges in addition to well‐recognised traditional ones when applied to delta/hexagonal PST. New challenges include non‐standard phase shift between two ends, saturation of the series winding, dependence of differential/restraining currents on tap changer position and turn–turn fault detection. This study exploits the unique design of PST and explores the suitability of applying electromagnetic equations by presenting a new algorithm for the protection of PST. In addition to the internal/external fault detection and discrimination capability, unlike differential protection, the proposed algorithm remains stable during magnetisation inrush current, current transformer saturation and saturation of the series winding. Even though the implementation of the proposed algorithm requires currents, voltages and tracking of the tap‐changer position, capabilities of the algorithm make it a distinguished and unique protection solution. Performance of the algorithm is tested and analysed for various fault and non‐faulted power system conditions using power systems computer aided design/electromagnetic transient including DC (PSCAD/EMTDC) software.
Dynamic modelling and control of distribution energy systems: comparison with transmission power systems
Authors: Nazari Masoud Honarvar , Ilic Marija
Published: September 2013

This paper explores the fundamental differences between distribution and transmission systems, regarding dynamic behaviour under a high penetration of distributed generators (DGs). The paper shows that because of large resistance to reactance ratio in distribution networks the frequency and voltage dynamics are strongly interdependent. Therefore only coupled models should be used for control design of DGs. Large resistance to reactance ratio and low inertia and fast dynamic response of DGs also result in strong interactions between DGs. These interactions can cause stability problems if DGs are connected electrically in close areas and/or the control of DGs is poorly tuned. Block Gerschgorin theorem is used to determine bounds on interactions between each DG with the rest of the system so that no interactions occur. Next, a more systematic fully decentralised, and, therefore simple control design is proposed. The logic of the decentralised control is to cancel out strong interactions between DGs and to improve the dynamic response of DGs. The theoretical findings are illustrated on two practical distribution systems.
Optimisation of arrester location in risk assessment in distribution network
Authors: Shariatinasab Reza , Ghayur Safar Jalil , Falaghi Hamid
Published: September 2013

This study describes a cost‐effective solution for distribution network protection against lightning surges by selective installation of arresters. To go through this, a probabilistic approach based on IEEE Std. 1410 has been implemented and an optimisation method based on discrete imperialist competition algorithm has been developed. The proposed method considers both technical and economic criteria to achieve the best solution. Consequently, the investment costs and the annual total costs including line investment, maintenance and outage costs are being reduced considering the cost of protective devices. In the optimisation procedure, lightning occurrence and network characteristics as well as transmitted power are considered. The obtained results confirm more efficiency of the proposed method than the conventional methods, from either economical or technical point of view.
Simple algorithm for calculating the total electric field of high‐voltage direct current transmission lines
Authors: Li Yong‐Ming , Li Wen
Published: September 2013

The basic equations of high‐voltage direct current transmission lines’ ion current field are consisted of electric field Poisson equation, ion current density equation and the current continuity equation, hence, the key to calculating total electric field is to solve the non‐linear differential equations, but the calculation process is very complicated. A simple algorithm is proposed to solve the problem in this study. First, the charge simulation method, an accurate numerical method, is employed to calculate the distribution of the electrical fields of a conductor. Then, the thought of emission charge is referred to calculate total electric field strength, this method does not need to adopt Deutsch hypothesis, and it avoids solving complex differential equations; hence, the calculation process can be greatly simplified. Finally, it is found that the calculated values agree satisfactorily with data measured on laboratory models and full‐scale test lines.
Dynamic load modelling of a paper mill for small signal stability studies
Authors: Wong Ke En , Haque Md Enamul
Published: September 2013

This study considers a power system with half the demand comprises of industrial loads with large rotating machines. The dynamic behaviour of these loads during disturbance is crucial to system stability. This study describes a practical approach to develop Laplace transfer function (TF) model of a mill load connected to this power system. A PSCAD/EMTDC™ simulation model of the mill (‘the detailed model’) is built from information on the types of load within the mill and verified in a piece‐wise manner, i.e., against individual motor starts. Instead of using generic load models, system identification theory is applied to evaluate the TF load model from simulated disturbance responses for both voltage and frequency changes. The main objective is to accurately represent the load behaviour particularly during small signal disturbances. It is recognised that large signal requirements of a load model for transient stability studies are important but the inevitable non‐linearity of such a model would tend to saturate the loads' behaviour during smaller disturbances. The developed small signal load model is then tested using practical disturbance profiles from this power system. This modelling approach allows development work to commence before real‐life disturbance measurements are available since such data are currently scant.
Preparation and antibacterial activity of magnesium oxide nanoplates via sol–gel process
Authors: Luo Fan , Lu Junwen , Wang Wei , Tan Fantang , Qiao Xueliang
Published: September 2013

Magnesium oxide (MgO) nanopowders were synthesised by a sol–gel method with different amounts of ammonium hydroxide (NH3 ·H2O) and characterised by a combination of thermo gravimetric analysis, X‐ray diffraction and transmission electron microscopy. It was found that the structure and morphology of MgO nanopowders can be regulated by the addition of NH3 ·H2O. When an appropriate amount of NH3 ·H2O was added into the reaction system, plate‐like nanoMgO was obtained. The antibacterial activity of MgO nanoplates was also investigated by the minimum inhibition concentration (MIC) test and bactericidal efficacy against Escherichia coli (E. coli, ATCC 25922). The tested results revealed that the MgO nanoplates have great antibacterial effect with an MIC value of 600 mg/l and the bactericidal rate was about 99.8% at a concentration of 500 mg/l. Furthermore, the effect of NH3 ·H2O on the structure and morphology of MgO nanopowders and on the growth mechanism are briefly discussed. The hydroxide ion of NH3 ·H2O, in favour of Mg(OH)2 generation in the precursors, is essential for the formation of MgO nanoplates.
Hydrothermal synthesis of high refractive index thin films from chromium slag
Authors: Sun Tong , Liu Lian‐li , Xu Shu‐ying , Wang Li‐li , Li Wei , Hao Han
Published: September 2013

Chromium slag is a hazardous waste, and its high‐value‐added comprehensive utilisation would be advantageous. High refractive index thin films were prepared on glass substrates by a hydrothermal method from chromium slag with different mineralisers. The samples were characterised by inductively coupled plasma, X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, an atomic force microscope, a transmission electron microscope and by film thickness and refractive index. The results show that a few Fe2O3, FeOOH, Al2O3, AlOOH or MgO crystals are formed, and most compounds of iron, aluminium, magnesium and chromium are still in amorphous state. The film materials are combined with a glass substrate by a chemical bond. The coordination ability of mineraliser anion and metal ion affects the sediment reaction rates. With NaClO3 or NaHCO3 as a mineraliser, the film surface is a perfect three‐dimensional space orientation network sediment with fine twines and small pores. The thinner the film, bigger the refractive index will be. The films’ refractive index is mainly related to the film structure and non crystalline phase.
Explicitly correlated composite thermochemistry of transition metal species
Authors: Bross David H. , Hill J. Grant , Werner H.-J. , Peterson Kirk A.
Published: September 2013

Atomization energies were calculated using explicitly correlated coupled cluster methods with correlation consistent basis sets for a series of 19 small molecules containing 3d transition metal atoms. The atomization energies were calculated using a modified Feller-Peterson-Dixon approach in which CCSD(T) complete basis set (CBS) limits were obtained using extrapolations of aVTZ/aVQZ CCSD(T)-F12b correlation energies, and then a series of additive contributions for relativity, core correlation, higher order correlation, and zero-point vibrations were included. The frozen-core CBS limits calculated with F12 methods closely matched the more computational expensive conventional awCVQZ/awCV5Z CBS extrapolations, with a mean unsigned deviation of just 0.1 kcal/mol. In particular, the CCSD(T*)-F12b/aVDZ and aVTZ atomization energies were more accurate on average than the conventional CCSD(T)/aVQZ and aV5Z results, respectively. In several cases the effects of higher order correlation beyond CCSD(T), as judged by CCSDT and CCSDT(Q)Λ calculations, were greater than 1 kcal/mol, reaching 4.5 kcal/mol for CrO3. For the 16 molecules of this study with experimental uncertainties of ∼3.5 kcal/mol or less, the final composite heats of formation have a mean unsigned deviation (MUD) from experiment of just 1.3 kcal/mol, which is slightly smaller than the average of the experimental uncertainties, 1.8 kcal/mol. The root mean square deviation (RMS) is only slightly larger at 1.7 kcal/mol. Without the contributions due to higher order correlation effects, the MUD and RMS rise to 2.1 and 2.8 kcal/mol, respectively. To facilitate the F12 calculations, new (aug-)cc-pVnZ/MP2Fit (n = Q, 5) and (aug-)cc-pwCVTZ/MP2Fit auxiliary basis sets were also developed for the transition metal atoms.
Perspective: Coarse-grained models for biomolecular systems
Authors: Noid W. G.
Published: September 2013

By focusing on essential features, while averaging over less important details, coarse-grained (CG) models provide significant computational and conceptual advantages with respect to more detailed models. Consequently, despite dramatic advances in computational methodologies and resources, CG models enjoy surging popularity and are becoming increasingly equal partners to atomically detailed models. This perspective surveys the rapidly developing landscape of CG models for biomolecular systems. In particular, this review seeks to provide a balanced, coherent, and unified presentation of several distinct approaches for developing CG models, including top-down, network-based, native-centric, knowledge-based, and bottom-up modeling strategies. The review summarizes their basic philosophies, theoretical foundations, typical applications, and recent developments. Additionally, the review identifies fundamental inter-relationships among the diverse approaches and discusses outstanding challenges in the field. When carefully applied and assessed, current CG models provide highly efficient means for investigating the biological consequences of basic physicochemical principles. Moreover, rigorous bottom-up approaches hold great promise for further improving the accuracy and scope of CG models for biomolecular systems.
Photoionization cross section by Stieltjes imaging applied to coupled cluster Lanczos pseudo-spectra
Authors: Cukras Janusz , Coriani Sonia , Decleva Piero , Christiansen Ove , Norman Patrick
Published: September 2013

A recently implemented asymmetric Lanczos algorithm for computing (complex) linear response functions within the coupled cluster singles (CCS), coupled cluster singles and iterative approximate doubles (CC2), and coupled cluster singles and doubles (CCSD) is coupled to a Stieltjes imaging technique in order to describe the photoionization cross section of atoms and molecules, in the spirit of a similar procedure recently proposed by Averbukh and co-workers within the Algebraic Diagrammatic Construction approach. Pilot results are reported for the atoms He, Ne, and Ar and for the molecules H2, H2O, NH3, HF, CO, and CO2.
Asymptotic flow in the depth of narrow cavity
Authors: Shtern Vladimir N.
Published: September 2013

It is shown that the viscous fluid motion in the depth of a narrow cavity is a counterflow moving and periodically varying along the cavity length. The obtained exact solutions of the Stokes equations describe unsteady three-dimensional flows, developing as the distance from the cavity surface increases. The found asymptotic motion is common for a variety of boundary conditions and cavity shapes. Creeping flows between parallel and inclined planes, coaxial cylinders, and concentric cones are particularly addressed. For these flows, the analytical asymptotes and numerical results merge as the gap width decreases.
Extended molecular Ornstein-Zernike integral equation for fully anisotropic solute molecules: Formulation in a rectangular coordinate system
Authors: Ishizuka Ryosuke , Yoshida Norio
Published: September 2013

An extended molecular Ornstein-Zernike (XMOZ) integral equation is formulated to calculate the spatial distribution of solvent around a solute of arbitrary shape and solid surfaces. The conventional MOZ theory employs spherical harmonic expansion technique to treat the molecular orientation of components of solution. Although the MOZ formalism is fully exact analytically, the truncation of the spherical harmonic expansion requires at a finite order for numerical calculation and causes the significant error for complex molecules. The XMOZ integral equation is the natural extension of the conventional MOZ theory to a rectangular coordinate system, which is free from the truncation of spherical harmonic expansion with respect to solute orientation. In order to show its applicability, we applied the XMOZ theory to several systems using the hypernetted-chain (HNC) and Kovalenko-Hirata approximations. The quality of results obtained within our theory is discussed by comparison with values from the conventional MOZ theory, molecular dynamics simulation, and three-dimensional reference interaction site model theory. The spatial distributions of water around the complex of non-charged sphere and dumbbell were calculated. Using this system, the approximation level of the XMOZ and other methods are discussed. To assess our theory, we also computed the excess chemical potentials for three realistic molecules (water, methane, and alanine dipeptide). We obtained the qualitatively reasonable results by using the XMOZ/HNC theory. The XMOZ theory covers a wide variety of applications in solution chemistry as a useful tool to calculate solvation thermodynamics.
Multiple solutions for Kirchhoff-type equations in $\mathbb {R}^N$RN
Authors: Ye Yiwei , Tang Chun-Lei
Published: September 2013

This paper is devoted to the existence of infinitely many solutions for a class of Kirchhoff-type equations setting on \documentclass[12pt]{minimal}\begin{document}$\mathbb {R}^N$\end{document}RN. Based on the minimax methods in critical point theory, we obtain infinitely many large-energy and small-energy solutions, which unify and sharply improve the recent results of Wu [“Existence of nontrivial solutions and high energy solutions for Schrödinger–Kirchhoff-type equations in RN,” Nonlinear Anal.: Real World Appl. 12, 1278–1287 (2011)].
A multichannel magnetic probe system for analysing magnetic fluctuations in helical axis plasmas
Authors: Haskey S. R. , Blackwell B. D. , Seiwald B. , Hole M. J. , Pretty D. G. , Howard J. , Wach J.
Published: September 2013

The need to understand the structure of magnetic fluctuations in H-1NF heliac [S. Hamberger et al., Fusion Technol. 17, 123 (1990)] plasmas has motivated the installation of a sixteen former, tri-axis helical magnetic probe Mirnov array (HMA). The new array complements two existing poloidal Mirnov arrays by providing polarisation information, higher frequency response, and improved toroidal resolution. The helical placement is ideal for helical axis plasmas because it positions the array as close as possible to the plasma in regions of varying degrees of favourable curvature in the magnetohydrodynamic sense, but almost constant magnetic angle. This makes phase variation with probe position near linear, greatly simplifying the analysis of the data. Several of the issues involved in the design, installation, data analysis, and calibration of this unique array are presented including probe coil design, frequency response measurements, mode number identification, orientation calculations, and mapping probe coil positions to magnetic coordinates. Details of specially designed digitally programmable pre-amplifiers, which allow gains and filters to be changed as part of the data acquisition initialisation sequence and stored with the probe signals, are also presented. The low shear heliac geometry [R. Jiménez-Gómez et al., Nucl. Fusion 51, 033001 (2011)]10.1088/0029-5515/51/3/033001, flexibility of the H-1NF heliac, and wealth of information provided by the HMA create a unique opportunity for detailed study of Alfvén eigenmodes, which could be a serious issue for future fusion reactors.
The aging of a surface and the evolution of conservative and dissipative nanoscale interactions
Authors: Amadei Carlo A. , Tang Tzu Chieh , Chiesa Matteo , Santos Sergio
Published: September 2013

A method to monitor variations in the conservative and dissipative forces in dynamic atomic force microscopy is proposed in order to investigate the effects of exposing a surface to different sets of environmental conditions for prolonged periods of time. The variations are quantified by proposing and defining two metrics, one for conservative and another for dissipative interactions. Mica and graphite are chosen as model samples because they are atomically flat and easy to cleave. It is found that long term exposure to high relative humidity (RH), i.e., 90% > RH > 70%, affects the magnitude and distance dependencies of the forces, as quantified by the respective metrics, more drastically than the actual environmental conditions at which the samples are probed. Attenuated total reflectance infrared spectroscopy experiments further indicate that accumulation of water and carbonates on the surfaces with time is responsible for the variations in force measurements. This study has implications in surface functionality, reactivity, and longevity.
Motion-adapted pulse sequences for oriented sample (OS) solid-state NMR of biopolymers
Authors: Lu George J. , Opella Stanley J.
Published: September 2013

One of the main applications of solid-state NMR is to study the structure and dynamics of biopolymers, such as membrane proteins, under physiological conditions where the polypeptides undergo global motions as they do in biological membranes. The effects of NMR radiofrequency irradiations on nuclear spins are strongly influenced by these motions. For example, we previously showed that the MSHOT-Pi4 pulse sequence yields spectra with resonance line widths about half of those observed using the conventional pulse sequence when applied to membrane proteins undergoing rapid uniaxial rotational diffusion in phospholipid bilayers. In contrast, the line widths were not changed in microcrystalline samples where the molecules did not undergo global motions. Here, we demonstrate experimentally and describe analytically how some Hamiltonian terms are susceptible to sample motions, and it is their removal through the critical π/2 Z-rotational symmetry that confers the “motion adapted” property to the MSHOT-Pi4 pulse sequence. This leads to the design of separated local field pulse sequence “Motion-adapted SAMPI4” and is generalized to an approach for the design of decoupling sequences whose performance is superior in the presence of molecular motions. It works by cancelling the spin interaction by explicitly averaging the reduced Wigner matrix to zero, rather than utilizing the 2π nutation to average spin interactions. This approach is applicable to both stationary and magic angle spinning solid-state NMR experiments.
GaAs metal-oxide-semiconductor based nonvolatile memory devices embedded with ZnO quantum dots
Authors: Kundu Souvik , Rao Gollu Sankara , Sharma Ramakant , Halder Nripendra. N , Biswas Pranab , Banerji P. , Gupta D.
Published: September 2013

Ultrathin InP passivated GaAs non-volatile memory devices were fabricated with chemically synthesized 5 nm ZnO quantum dots embedded into ZrO2 high-k oxide matrix deposited through metal organic chemical vapor deposition. In these memory devices, the memory window was found to be 6.10 V and the obtained charge loss was only 15.20% after 105 s. The superior retention characteristics and a wide memory window are achieved due to presence of ZnO quantum dots between tunneling and control oxide layers. Room temperature Coulomb blockade effect was found in these devices and it was ascertained to be the main reason for low leakage. Electronic band diagram with program and erase operations were described on the basis of electrical characterizations.
Facet recovery and light emission from GaN/InGaN/GaN core-shell structures grown by metal organic vapour phase epitaxy on etched GaN nanorod arrays
Authors: Le Boulbar E. D. , Gîrgel I. , Lewins C. J. , Edwards P. R. , Martin R. W. , Šatka A. , Allsopp D. W. E. , Shields P. A.
Published: September 2013

The use of etched nanorods from a planar template as a growth scaffold for a highly regular GaN/InGaN/GaN core-shell structure is demonstrated. The recovery of m-plane non-polar facets from etched high-aspect-ratio GaN nanorods is studied with and without the introduction of a hydrogen silsesquioxane passivation layer at the bottom of the etched nanorod arrays. This layer successfully prevented c-plane growth between the nanorods, resulting in vertical nanorod sidewalls (∼89.8°) and a more regular height distribution than re-growth on unpassivated nanorods. The height variation on passivated nanorods is solely determined by the uniformity of nanorod diameter, which degrades with increased growth duration. Facet-dependent indium incorporation of GaN/InGaN/GaN core-shell layers regrown onto the etched nanorods is observed by high-resolution cathodoluminescence imaging. Sharp features corresponding to diffracted wave-guide modes in angle-resolved photoluminescence measurements are evidence of the uniformity of the full core-shell structure grown on ordered etched nanorods.
Photoluminescence modulation of ZnO via coupling with the surface plasmon resonance of gold nanoparticles
Authors: Zhang Dongyan , Ushita Hiroki , Wang Pangpang , Park Changwook , Murakami Ri-ichi , Yang Sheng-chun , Song Xiaoping
Published: September 2013

In this letter, we study how coupling between AuNPs and ZnO thin films affects their emission properties. The emission intensity of ZnO thin films changes when Al2O3 spacer layer of different thickness is included in ZnO/Au films, consistent with theoretical predictions. The emission properties are also controlled using the polarization of the excitation source. Emission properties depended on the polarization of the excitation source because of the surface plasmon resonance of AuNPs. The photoluminescence anisotropy of these systems shows that enhanced photoluminescence can be achieved through coupling of the emission from ZnO with the surface plasmon resonance of AuNPs.