bluuebunny/crossref_metadata_2025 huggingface dataset:
Nature of the anomalies in the supercooled liquid state of the mW model of water
Authors: Holten Vincent , Limmer David T. , Molinero Valeria , Anisimov Mikhail A.
Published: May 2013

The thermodynamic properties of the supercooled liquid state of the mW model of water show anomalous behavior. Like in real water, the heat capacity and compressibility sharply increase upon supercooling. One of the possible explanations of these anomalies, the existence of a second (liquid–liquid) critical point, is not supported by simulations for this model. In this work, we reproduce the anomalies of the mW model with two thermodynamic scenarios: one based on a non-ideal “mixture” with two different types of local order of the water molecules, and one based on weak crystallization theory. We show that both descriptions accurately reproduce the model's basic thermodynamic properties. However, the coupling constant required for the power laws implied by weak crystallization theory is too large relative to the regular backgrounds, contradicting assumptions of weak crystallization theory. Fluctuation corrections outside the scope of this work would be necessary to fit the forms predicted by weak crystallization theory. For the two-state approach, the direct computation of the low-density fraction of molecules in the mW model is in agreement with the prediction of the phenomenological equation of state. The non-ideality of the “mixture” of the two states never becomes strong enough to cause liquid–liquid phase separation, also in agreement with simulation results.
The double-layer of penetrable ions: An alternative route to charge reversal
Authors: Frydel Derek , Levin Yan
Published: May 2013

We investigate a double-layer of penetrable ions near a charged wall. We find a new mechanism for charge reversal that occurs in the weak-coupling regime and, accordingly, the system is suitable for the mean-field analysis. The penetrability is achieved by smearing-out the ionic charge inside a sphere, so there is no need to introduce non-electrostatic forces and the system in the low coupling limit can be described by a modified version of the Poisson-Boltzmann equation. The predictions of the theory are compared with the Monte Carlo simulations.
Coulomb-distorted plane wave: Partial wave expansion and asymptotic forms
Authors: Hornyak I. , Kruppa A. T.
Published: May 2013

Partial wave expansion of the Coulomb-distorted plane wave is determined and studied. Dominant and sub-dominant asymptotic expansion terms are given and leading order three-dimensional asymptotic form is derived. The generalized hypergeometric function 2F2(a, a; a + l + 1, a − l; z) is expressed with the help of confluent hypergeometric functions and the asymptotic expansion of 2F2(a, a; a + l + 1, a − l; z) is simplified.
Schrödinger-Virasoro Lie conformal algebra
Authors: Su Yucai , Yuan Lamei
Published: May 2013

We first construct two new nonsimple conformal algebras associated with the Schrödinger-Virasoro Lie algebra and the extended Schrödinger-Virasoro Lie algebra, respectively. Then we study conformal derivations and free nontrivial rank one conformal modules of these two conformal algebras. Also, we provide a computation of their universal central extensions.
Heteroepitaxy of GaAs on (001) ⇒ 6° Ge substrates at high growth rates by hydride vapor phase epitaxy
Authors: Schulte K. L. , Wood A. W. , Reedy R. C. , Ptak A. J. , Meyer N. T. , Babcock S. E. , Kuech T. F.
Published: May 2013

The growth of GaAs on (001) ⇒ 6° Ge substrates by hydride vapor phase epitaxy has been investigated. The effects of varying deposition temperature and gas phase supersaturation on growth rate and material quality as determined by atomic force microscopy measured surface roughness and x-ray diffraction were established. GaAs growth rates up to 44 μm/hr were achieved. The deposition temperature has a strong effect on growth rate under the investigated range of growth conditions indicating that growth is typically limited by surface kinetic processes. An apparent activation energy of 35.1 ± 2.0 kcal/mol was determined for growth on these Ge substrates, agreeing well with past kinetic data for GaAs growth on GaAs substrates. The deposition temperature also had a significant effect on both root mean square surface roughness and x-ray full width at half maximum, with minima of 0.92 nm and 26 arcsec occurring for samples grown at temperatures of 725 °C and 750 °C, respectively. These values are comparable to or better than values measured for GaAs on Ge layers grown by metalorganic vapor phase epitaxy. The use of a thin Si3N4 coating on the Ge substrate backside mitigated the observed Ge gas phase autodoping effect. With back surface passivation, GaAs background doping levels within the GaAs epilayer of n = 1.2 × 1016 cm−3 were achieved 2.3 μm from the heterointerface. The heterointerfaces of the samples grown at 725 °C and 775 °C were imaged by transmission electron microscopy. Anti-phase domain boundaries (APBs) were observed near the heterointerface of the 775 °C sample. These APBs self-annihilated after roughly 100 nm of epilayer thickness. The 725 °C sample exhibited no APBs in the vicinity of the interface or elsewhere in the film, indicating a more optimal growth temperature. Ge diffusion through the GaAs/Ge interface was profiled by secondary ion mass spectrometry and multiple regions of diffusion behavior were observed. In the region of high Ge concentration ([Ge] > 5 × 1019 cm−3) closest to the heterointerface, the concentration vs. position data fit a vacancy-assisted diffusion mechanism. The data between 0.05 and 0.20 μm from the heterointerface were fit to a concentration independent, semi-infinite diffusion model with a constant diffusion coefficient. These models indicate that complex mechanisms control diffusion during growth at these temperatures.
Asymptotic behaviour of optimal spectral planar domains with fixed perimeter
Authors: Bucur Dorin , Freitas Pedro
Published: May 2013

We consider the problem of minimizing the kth Dirichlet eigenvalue of planar domains with fixed perimeter and show that, as k goes to infinity, the optimal domain converges to the ball with the same perimeter. We also consider this problem within restricted classes of domains such as n-polygons and tiling domains, for which we show that the optimal asymptotic domain is that which maximises the area for fixed perimeter within the given family, i.e., the regular n-polygon and the regular hexagon, respectively. Physically, the above problems correspond to the determination of the shapes within a given class which will support the largest number of modes below a given frequency.
Atomic structure and electronic properties of folded graphene nanoribbons: A first-principles study
Authors: Yin Wen-Jin , Xie Yue-E , Liu Li-Min , Chen Yuan-Ping , Wang Ru-Zhi , Wei Xiao-Lin , Zhong Jian-Xin , Lau Leo
Published: May 2013

Folded graphene nanoribbons (FGNRs) have attracted great attentions because of extraordinary properties and potential applications. The atomic structure, stacking sequences, and electronic structure of FGNRs are investigated by first-principle calculations. It reveals that the common configurations of all FGNRs are racket-like structures including a nanotube-like edge and two flat nanoribbons. Interestingly, the two flat nanoribbons form new stacking styles instead of the most stable AB-stacking sequences for flat zone. The final configurations of FGNRs are greatly affected by the initial interlayer distance, stacking sequences, and edge styles. The stability of folded graphene nanoribbon depends on the length, and it can only be thermodynamically stable when it reaches the critical length. The band gap of the folded zigzag graphene nanoribbons becomes about 0.17 eV, which provides a new way to open the band gap.
Temporal properties of secondary drop breakup in the bag-stamen breakup regime
Authors: Zhao Hui , Liu Hai-Feng , Xu Jian-Liang , Li Wei-Feng , Lin Kuang-Fei
Published: May 2013

The situation of liquid drop bag-stamen breakup in a continuous air jet flow is investigated by a high speed camera. Test liquids include water, ethanol, and various glycerol mixtures. First, the morphology of bag-stamen breakup is observed and analyzed. The bag-stamen breakup range is found to be in good agreement with the model obtained by Rayleigh-Taylor instability. Then the disk and stamen deformation properties, the fragment average size, and size distribution of ring and stamen are researched in detail, respectively.
Relaxation calorimeter for hydrogen thermoporometry
Authors: Van Cleve E. , Worsley M. A. , Kucheyev S. O.
Published: May 2013

A relaxation calorimeter for measuring the heat capacity of hydrogen isotopes in nanoporous solids is described. Apparatus’ features include (i) cooling by a pulse tube refrigerator, (ii) a modular design, allowing for rapid reconfiguration and sample turn around, (iii) a thermal stability of ≲1 mK, and (iv) a bottom temperature of ∼5 K. The calorimeter is tested on effective heat capacity measurements of H2 in Vycor (silica) nanoporous glass, yielding a very detailed pore size distribution analysis with an effectively sub-Angstrom resolution.
Design and implementation of a novel rotary micropositioning system driven by linear voice coil motor
Authors: Xu Qingsong
Published: May 2013

Limited-angle rotary micropositioning stages are required in precision engineering applications where an ultrahigh-precision rotational motion within a restricted range is needed. This paper presents the design, fabrication, and control of a compliant rotary micropositioning stage dedicated to the said applications. To tackle the challenge of achieving both a large rotational range and a compact size, a new idea of multi-stage compound radial flexure is proposed. A compact rotary stage is devised to deliver an over 10° rotational range while possessing a negligible magnitude of center shift. The stage is driven by a linear voice coil motor and its output motion is measured by laser displacement sensors. Analytical models are derived to facilitate the parametric design, which is validated by conducting finite element analysis. The actuation and sensing issues are addressed to guarantee the stage performance. A prototype is fabricated and a proportional-integral-derivative control is implemented to achieve a precise positioning. Experimental results demonstrate a resolution of 2 μrad over 10° rotational range as well as a low level of center shift of the rotary micropositioning system.
Recombination dynamics in single GaAs-nanowires with an axial heterojunction: n- versus p-doped areas
Authors: Sager D. , Gutsche C. , Prost W. , Tegude F.-J. , Bacher G.
Published: May 2013

The recombination dynamics of vapor-liquid-solid grown GaAs-nanowires with an axial p-n heterojunction is investigated by spatially and time-resolved photoluminescence spectroscopy. By scanning across the doping transition of single p-n and n-p doped nanowires, respectively, the particular influence of surface losses in differently doped areas is studied. We found a significantly reduced non-radiative recombination for the n-doped region compared to the p-doped one, which can be attributed to suppressed surface losses because of the characteristic band bending at the surface.
Transport and interfacial transfer of electrons in dye-sensitized solar cells based on a TiO2 nanoparticle/TiO2 nanowire “double-layer” working electrode
Authors: Wei Aixiang , Zuo Zhipeng , Liu Jun , Lin Kangbao , Zhao Yu
Published: May 2013

Dye-sensitized solar cells (DSSCs) with different thickness TiO2 nanoparticle films and a “double-layer” working electrode of TiO2 nanoparticle/TiO2 nanowire are fabricated. The influence of the TiO2 nanoparticle films thickness and of a light-scattering layer of TiO2 nanowire on the photovoltaic performance of DSSCs are investigated. The transport and interfacial transfer of electrons in DSSCs are investigated using intensity modulated photocurrent spectroscopy (IMPS), intensity modulated photovoltage spectroscopy (IMVS), and electrochemical impedance spectroscopy (EIS) to determine the lifetime, diffusion coefficient, and diffusion length of the electrons. The results indicate that the optimum TiO2 nanoparticle films' thickness for DSSCs is about 14 μm. The introduction of the light-scattering layer leads to an obvious enhancement of the power conversion efficiency. This can mainly be attributed to the superior light-scattering ability, fast electron transport, and long electron lifetime, resulting in a larger electron diffusion coefficient and a higher charge collection efficiency, which are confirmed by IMPS, IMVS, and EIS.
A spatially smoothed device model for organic bulk heterojunction solar cells
Authors: Zhang Teng , Birgersson Erik , Luther Joachim
Published: May 2013

The performance of organic bulk heterojunction (BHJ) solar cells depends strongly on the nanoscale morphology formed by the donor and acceptor materials. However, the majority of device models for organic BHJ solar cells are based on an effective-medium formulation that does not capture details of the underlying morphology. In order to link more detailed models with effective-medium models, we derive a spatially smoothed formulation for organic BHJ solar cells based on volume-averaging of a mathematical model that considers charge carrier transport, generation, and recombination in both the acceptor and donor phases. The formulation captures two essential morphological characteristics of the organic BHJ layer that are not found in existing effective-medium models: the effective interfacial area and the volume fraction ratio between donor and acceptor materials. In addition, effective charge carrier mobilities and diffusion coefficients are identified, which are determined for an “ideal” interpenetrated BHJ solar cell.
Observation of photo darkening in self assembled InGaAs/GaAs quantum dots
Authors: Zhang Hongyi , Chen Yonghai , Zhou Xiaolong , Jia Yanan , Ye Xiaoling , Xu Bo , Wang Zhanguo
Published: May 2013

Photo darkening was observed in epitaxial InGaAs/GaAs quantum dots (QDs). The photoluminescence (PL) intensity of the QDs showed a non-reversible decrease under continuous laser irradiation. The time constants varied from tens of minutes to several hours, depending on the applied laser power. Based on the spectral evolution, it was concluded that the observed phenomenon should originate from laser induced structural damage and a sustained increase of non-radiative recombination rate in the wetting layer. Additionally, according to the PL decay dynamics at different laser powers, it is argued that there should exist other processes that hinder PL degradation at a high laser power.
Vibrational stability of graphene
Authors: Hu Yangfan , Wang Biao
Published: May 2013

The mechanical stability of graphene as temperature rises is analyzed based on three different self-consistent phonon (SCP) models. Compared with three-dimensional (3-D) materials, the critical temperature Ti at which instability occurs for graphene is much closer to its melting temperature Tm obtained from Monte Carlo simulation (Ti ≃ 2Tm, K. V. Zakharchenko, A. Fasolino, J. H. Los, and M. I. Katsnelson, J. Phys. Condens. Matter 23, 202202). This suggests that thermal vibration plays a significant role in melting of graphene while melting for 3-D materials is often dominated by topologic defects. This peculiar property of graphene derives from its high structural anisotropy, which is characterized by the vibrational anisotropic coefficient (VAC), defined upon its Lindermann ratios in different directions. For any carbon based material with a graphene-like structure, the VAC value must be smaller than 5.4 to maintain its stability. It is also found that the high VAC value of graphene is responsible for its negative thermal expansion coefficient at low temperature range. We believe that the VAC can be regarded as a new criterion concerning the vibrational stability of any low-dimensional (low-D) materials.
Resolving Zeeman splitting in quantum dot ensembles
Authors: Taylor Matthew W. , Spencer Peter , Clarke Edmund , Harbord Edmund , Murray Ray
Published: May 2013

This letter presents a technique for the investigation of the fine structure and spin properties of quantum dot (QD) ensembles, allowing measurement of QD parameters previously accessible only from studies of individual QDs. We show how ∼μeV splittings can be deduced from information contained in the shape of the ensemble polarization spectra and demonstrate the effectiveness of this technique by measuring Zeeman splittings, g-factors, and sensitivity to QD fine structure effects.
Assessing ways to combat eutrophication in a Chinese drinking water reservoir using SWAT
Authors: Nielsen Anders , Trolle Dennis , Me Wang , Luo Liancong , Han Bo-Ping , Liu Zhengwen , Olesen Jørgen E. , Jeppesen Erik
Published: May 2013

Across China, nutrient losses associated with agricultural production and domestic sewage have triggered eutrophication, and local managers are challenged to comply with drinking water quality requirements. Evidently, the improvement of water quality should be targeted holistically and encompass both point sources and surface activities within the watershed of a reservoir. We expanded the ordinary Soil Water Assessment Tool – (SWAT) with a widely used empirical equation to estimate total phosphorus (TP) concentrations in lakes and reservoirs. Subsequently, we examined the effects of changes in land and livestock management and sewage treatment on nutrient export and derived consequences for water quality in the Chinese subtropical Kaiping (Dashahe) drinking water reservoir (supplying 0.4 million people). The critical load of TP was estimated to 13.5 tonnes yr–1 in order to comply with the minimum drinking water requirements, which corresponds to 87% of the simulated load to the reservoir at present. Both the implementation of buffer zones along rivers and removal of sewage discharges showed marked improvement in reservoir water quality. Future research should focus on both hydrological model performance and nutrient transport pathways, which are challenged by a complex artificially altered water infrastructure in the form of ditches, channels and ponds in monsoon-influenced subtropical watersheds.
Effects of nutrient loading on the trophic state of Lake Brunner
Authors: Verburg P. , Horrox J. , Chaney E. , Rutherford J. C. , Quinn J. M. , Wilcock R. J. , Howard-Williams C. W.
Published: May 2013

Lake Brunner, an oligotrophic monomictic lake on the West Coast of the South Island of New Zealand, is under pressure from urban expansion and increased farming activity, which has led to concern for the effects on water quality in the lake. Epilimnetic nitrogen, phosphorus and chlorophyll a concentrations have increased since 1992, and Secchi depth decreased. This suggests an increased algal productivity caused by increased nutrient inputs, further supported by increased hypolimnetic oxygen depletion since 1992. These observations are likely to have resulted from enhancement of pasture drainage and effluent inputs from expanding dairy farms. The Vollenweider model predicted a mean phosphorus concentration in the lake close to that observed, from estimated catchment loading, suggesting that the Vollenweider model adequately estimated the retention of phosphorous. With the Vollenweider model the effects of potential future loading scenarios were explored. Modelling suggested that a 70% increase in phosphorus loading could turn the lake into a mesotrophic state. Trend analysis of total phosphorus suggests that, with present land uses in the catchment (intensive dairy farming) continuing to develop at the same rate using the same land management practises, this transition to a mesotrophic state will occur by 2040.
Drivers of long-term trends and seasonal changes in total phosphorus loads to a mesotrophic lake in the west of Ireland
Authors: Jennings Eleanor , Allott Norman , Lenihan David , Quirke Bill , Taylor David , Twomey Helena
Published: May 2013

Excess phosphorus (P) loading is a major cause of deterioration in surface water quality. In Ireland, regulation has focussed on control of P losses from agriculture and wastewater treatment plants (WWTPs): the two main sources of excess P. Hindcast modelling for Lough Leane, south-west Ireland, indicated that, while the only municipal (point) source contributed up to 41% of the annual TP loading until the mid 1980s, over 90% of the TP load was from diffuse sources following upgrading of the WWTP. Field data from 2000–2006 confirmed that most of the TP load came from agriculture, with 73% being exported between September and February, generally the wettest months in the region. However, the WWTP contributed up to 60% of daily loads during summer. Short lake residence times (two to four months) between October and February indicated that external loadings during these months were unlikely to make a significant contribution to summer phytoplankton growth in the lake. In contrast, the potential effects of point sources during low flows were maximised by longer residence times between April and September. The results highlight the importance to aquatic pollution impacts of, and therefore the need for regulatory responses to respect, seasonal variations in loading and residence time.
Direct urine polymerase chain reaction for chlamydia and gonorrhoea: a simple means of bringing high-throughput rapid testing to remote settings?
Authors: Rahimi Frashta , Goire Namraj , Guy Rebecca , Kaldor John M. , Ward James , Nissen Michael D. , Sloots Theo P. , Whiley David M.
Published: May 2013

Background
Rapid point-of-care tests (POCTs) for chlamydia (Chlamydia trachomatis) and gonorrhoea (Neisseria gonorrhoeae) have the potential to confer health benefits in certain populations even at moderate sensitivities; however, suitable POCTs for these organisms are currently lacking. Methods: In this study, we investigated the use of direct urine polymerase chain reaction (PCR), with the view of implementing a simplified PCR strategy for high-throughput chlamydia and gonorrhoea screening in remote settings. Briefly, a simple dilution of the urine was performed before adding it directly to a real-time PCR reaction. The method was evaluated using 134 stored urine specimens that had been submitted for chlamydia and gonorrhoea testing and had been tested using a commercial C. trachomatis and N. gonorrhoeae PCR method. These included samples that were PCR-positive for chlamydia (n = 87), gonorrhoea (n = 16) or both (n = 2). Direct urine testing was conducted using previously described in-house real-time PCR methods for C. trachomatis and N. gonorrhoeae as well as for recognised N.gonorrhoeae antimicrobial resistance mechanisms. Results: The overall sensitivities and specificities of the direct urine PCR were 78% and 100% for chlamydia, and 83% and 100% for gonorrhoea. N.gonorrhoeae penicillin and quinolone resistance mechanisms were characterised in 14 of the 18 N. gonorrhoeae-positive samples. Conclusions: The results of this study show that the simplified PCR strategy may be a feasible approach for rapid screening and improving chlamydia and gonorrhoea treatment in remote settings.
Chloride binding site of neurotransmitter sodium symporters
Authors: Kantcheva Adriana K. , Quick Matthias , Shi Lei , Winther Anne-Marie Lund , Stolzenberg Sebastian , Weinstein Harel , Javitch Jonathan A. , Nissen Poul
Published: May 2013

Neurotransmitter:sodium symporters (NSSs) play a critical role in signaling by reuptake of neurotransmitters. Eukaryotic NSSs are chloride-dependent, whereas prokaryotic NSS homologs like LeuT are chloride-independent but contain an acidic residue (Glu290 in LeuT) at a site where eukaryotic NSSs have a serine. The LeuT-E290S mutant displays chloride-dependent activity. We show that, in LeuT-E290S cocrystallized with bromide or chloride, the anion is coordinated by side chain hydroxyls from Tyr47, Ser290, and Thr254 and the side chain amide of Gln250. The bound anion and the nearby sodium ion in the Na1 site organize a connection between their coordinating residues and the extracellular gate of LeuT through a continuous H-bond network. The specific insights from the structures, combined with results from substrate binding studies and molecular dynamics simulations, reveal an anion-dependent occlusion mechanism for NSS and shed light on the functional role of chloride binding.
Improving on sputum smear microscopy for diagnosis of tuberculosis in resource-poor settings.
Authors: Ramsay A. , Steingart K. R. , Madhukar Pai Madhukar Pai
Published: May 2013

This chapter discusses the limitations of direct sputum smear microscopy for diagnosis of tuberculosis as practised currently, reviews the recent WHO recommendations, and discusses how the performance of sputum smear microscopy may be improved. It also explores how sputum smear microscopy services may be complemented by add-on tests and identifies which tests (now and in the future) may replace smear microscopy in certain defined situations.
Molecular diagnosis of active pulmonary tuberculosis.
Authors: Bateson A. L. , Reddington K. , O'Grady J.
Published: May 2013

This chapter describes molecular diagnostic methods for pulmonary tuberculosis according to 3 groups: nucleic acid amplification tests (NAATs), molecular line probe assays (LPAs) and sequencing assays. It covers both commercial and in-house methods for the detection of the Mycobacterium tuberculosis complex (MTC), differentiation of the MTC and molecular drug susceptibility testing (DST) for anti-M. tuberculosis drugs. The advantages, disadvantages and future of molecular diagnosis for tuberculosis, including point-of-care (POC) diagnostic tests, are also discussed.
Improving on the LJ slope - automated liquid culture.
Authors: Viveiros M. , Machado D. , Couto I. , Amaral L.
Published: May 2013

This chapter describes the different types of media for culture and isolation of mycobacteria, and discusses the adaptation of automated liquid culture systems for the qualitative and quantitative drug susceptibility testing of Mycobacterium tuberculosis and non-tuberculous mycobacteria.
Sniffing out tuberculosis.
Authors: McNerney R. , Turner C.
Published: May 2013

This chapter describes the analysis of volatile organic compounds (VOCs) for disease detection and reviews progress towards a diagnostic test for tuberculosis. The human olfactory detection of tuberculosis, the volatile biomarkers of tuberculosis, and the use of e-noses, chromatography and mass spectrometry in VOC analysis are discussed.
Genotypic measures of antibiotic susceptibility.
Authors: Mathys V. , Mathema B. , Bifani P.
Published: May 2013

This chapter reviews the genetic basis of drug resistance in Mycobacterium tuberculosis and correlates to phenotypic antibiotic susceptibility. It focuses on antituberculous agents (rifampicin, isoniazid, ethionamide, pyrazinamide, ethambutol, fluoroquinolones, para-aminosalicylic acid, aminoglycosides and macrocyclic polypeptide antibiotics) and drug resistance-conferring mutations that are most relevant in the clinical and epidemiological settings.
Mycobacterial lipid bodies and resuscitation-promoting factor dependency as potential biomarkers of response to chemotherapy.
Authors: Garton N. J. , Mukamolova G. V. , Barer M. R.
Published: May 2013

This chapter discusses sputum Mycobacterium tuberculosis phenotypes (slow/non-growth, lipid bodies and resuscitation-promoting factor dependency) and their potential as biomarkers for the assessment of patient response to therapy. The relationship between sputum M. tuberculosis phenotypes and antibiotic tolerance is described.
Clinical trials in tuberculosis chemotherapy: the challenges.
Authors: Gillespie S. H.
Published: May 2013

This chapter discusses the challenges in clinical trials of tuberculosis treatment, considering trial design, subjects, location and laboratory methodology.
Vaccines for tuberculosis.
Authors: McShane H.
Published: May 2013

This chapter describes the existing vaccines against tuberculosis, the nature of the protective immune response to tuberculosis, and the target populations for a new tuberculosis vaccine. The preclinical animal testing and clinical evaluation of candidate vaccines, the potential approaches to the development of a new tuberculosis vaccine, and the major challenges to tuberculosis vaccine development are reviewed.
The Shapes of Sociability in the Instrumental Music of the Later Eighteenth Century
Authors: Sutcliffe W. Dean
Published: May 2013

The particular listener-friendliness of later eighteenth-century music is no secret; it has been an article of faith for some more recent writers, but has not that often informed the basic approach to this repertory. Theories of rhetoric, schema or topic are certainly premissed on such an understanding, but do not necessarily address what the author believes to be a central aspect of the musical aesthetics (and indeed of the wider culture) of the time: sociability. Yet music, especially instrumental music, arguably forms the most powerful expression of sociability that has reached us from that time – not merely reflecting wider practices but actively providing models for human behaviour. I discuss some of the common syntactical mechanisms that convey the sociable impulse, in line with Judith Schwartz's definition of an art that ‘communicate[s] by means of pattern rather than momentary passion’, and with particular reference to Pleyel, J. C. Bach and Haydn.
Secret Letters and a Missing Memorandum: New Light on the Personal Relationship between Felix Mendelssohn and Jenny Lind
Authors: Biddlecombe George
Published: May 2013

The Committee of the Mendelssohn Scholarship Foundation possesses material indicating that Mendelssohn wrote passionate love letters to Jenny Lind entreating her to join him in an adulterous relationship and threatening suicide as a means of exerting pressure upon her, and that these letters were destroyed on being discovered after her death. The notion that Mendelssohn would have written such letters conflicts strikingly with the received view of his character. Nevertheless, the veracity of the material is beyond doubt, and, while it does not include specific evidence that Mendelssohn and Lind began an affair, it points more clearly than has hitherto been possible towards an answer to this question. Thus it necessitates a radical revision of perceptions of these two major musicians. For Otto Goldschmidt, Lind's husband, destroying the letters was crucial in protecting the reputations not only of his wife and Mendelssohn but also of himself and his family.
Number Representation: A Question of Look? The Distance Effect in Comparison of English and Turkish Number Words
Authors: Lukas Sarah , Krinzinger Helga , Koch Iring , Willmes Klaus
Published: May 2013

Cohen Kadosh found that Hebrew number words and Arabic digits elicited different distance effects. The numerical distance effect (i.e., faster reaction times and smaller error rates for numbers with larger distance to a standard number, e.g., 5) was smaller for number words than for digits. The author suggested that the result indicated a notation-dependent (i.e., nonabstract) numerical representation. Alternatively, however, it is possible that the distance effect was decreased by perceptual features of the Hebrew number words used as stimuli. To test this hypothesis, we replicated the study of Cohen Kadosh, but with English and Turkish number words compared to Arabic digits. The perceptual features of Turkish number words lead to the hypothesis that the opposite effect should be present: an increased distance effect for number words compared to Arabic digits. On the other hand, English number words show features similar to those of Hebrew number words, thus leading to the expectation of a decreased distance effect for them. Our results confirmed our hypotheses. We conclude that the distance effect can be influenced also by perceptual features in addition to the impact of numerical representations.
The effect of intravenous ferric carboxymaltose on red cell distribution width: a subanalysis of the FAIR‐HF study
Authors: Van Craenenbroeck Emeline M. , Conraads Viviane M. , Greenlaw Nicola , Gaudesius Giedrius , Mori Claudio , Ponikowski Piotr , Anker Stefan D.
Published: May 2013

Aims

Red cell distribution width (RDW), a measure of variability in red blood cell size, is a novel prognostic marker in chronic heart failure (CHF). Iron deficiency contributes to elevated RDW. In the FAIR‐HF trial, i.v. ferric carboxymaltose (FCM) improved the 6 min walk test (6MWT) distance in iron‐deficient CHF patients. We studied the effect of FCM on RDW and the relationship between RDW and 6MWT distance.

Methods and results

In FAIR‐HF, iron‐deficient CHF patients were randomized to FCM or placebo in a 2:1 ratio. From the total cohort (n = 459), we included 415 patients in whom RDW values and 6MWT distance were available for baseline and at least one follow‐up visit (after 4, 12, and 24 weeks). Baseline RDW was higher in anaemic (haemoglobin <12 g/dL) compared with non‐anaemic patients [15.2% (14.0–16.8) vs. 14.2% (13.4–15.4), P < 0.0001, median (interquartile range)]. In multivariate analysis, RDW was significantly associated with transferrin saturation (P < 0.001) and C‐reactive protein levels (P = 0.002). Treatment with FCM led to a biphasic response; RDW increased within 4 weeks (+0.54% absolute change from baseline, P = 0.01) but fell to values below the placebo group after 24 weeks (–1.0 %, P = 0.03). The 6MWT distance and RDW were inversely related at baseline (r = –0.30, P < 0.0001). In all patients, the increase in 6MWT distance after 24 weeks was significantly correlated with a decrease in RDW (r= –0.25, P < 0.0001), even after adjustment for changes in haemoglobin.

Conclusions

Iron deficiency in CHF is associated with high RDW, even after adjustment for the presence of anaemia. Treatment with i.v. FCM in iron‐deficient CHF patients decreases RDW.
Clinical and neurohormonal correlates and prognostic value of serum prolactin levels in patients with chronic heart failure
Authors: Parissis John T. , Farmakis Dimitrios , Fountoulaki Katerina , Rigas Antonios , Nikolaou Maria , Paraskevaidis Ioannis A. , Bistola Vassiliki , Venetsanou Koula , Ikonomidis Ignatios , Anastasiou‐Nana Maria , Kremastinos Dimitrios T. , Filippatos Gerasimos
Published: May 2013

Aims

Hypothalamic axis deregulation is associated with clinical severity and depression in chronic heart failure (CHF). We investigated the relationship of serum prolactin, an indicator of hypothalamic axis function, to neurohomonal/immune activation and depressive symptoms in CHF as well as its prognostic value.

Methods and results

Serum prolactin was determined in 180 patients with advanced CHF (aged 65 ± 12 years, mean LVEF 27 ± 7%) along with natriuretic peptides (BNP), inflammatory cytokines, endothelial adhesion molecules, 6 min walk test (6MWT), and the Zung self‐rating depression scale (SDS). Patients were followed for all‐cause death or hospitalization for cardiovascular reasons for up to 8 months. Prolactin levels were significantly correlated with NYHA class (r = 0.394, P < 0.001), LVEF (r = –0.314, P < 0.001), 6MWT (r = –0.353, P < 0.001), BNP (r = 0.374, P < 0.001), Zung SDS (r = 0.544, P < 0.001), interleukin‐6 (IL‐6) (r = 0.451, P < 0.001), IL‐10 (r = –0.426, P < 0.001), tumour necrosis factor (TNF)‐α (r = 0.310, P = 0.001), soluble Fas (r = 0.333, P < 0.001), soluble Fas‐ligand (r = 0.517, P < 0.001), soluble intercellular adhesion molecule‐1 (ICAM‐1) (r = 0.409, P < 0.001), and soluble vascular cell adhesion molecule‐1 (VCAM‐1) (r = 0.480, P < 0.001). During follow‐up, 119 patients (66%) died or were hospitalized for cardiovascular events after a median time of 72 days (range 5–220 days); these patients had higher baseline prolactin levels (10.2 ± 5.7 vs. 6.7 ± 4.3 ng/mL, P < 0.001), and a prolactin value ≥4.5 ng/mL was associated with a higher rate of death or hospitalization (116 ± 7 vs. 181 ± 11 days, P = 0.0001). In multivariate analysis, prolactin levels remained an independent predictor of death or hospitalization (<4.5 vs. ≥4.5 ng/mL; odds ratio, 0.368; 95% confidence interval 0.148–0.913; P = 0.031), along with BNP (P < 0.001) and 6MWT (P = 0.020).

Conclusions

Serum prolactin is associated with neurohormonal/immune activation and depressive symptoms and is an independent predictor of prognosis in advanced CHF.
Presence of Clostridium difficile PCR ribotype clusters related to 033, 078 and 045 in diarrhoeic calves in Germany
Authors: Schneeberg Alexander , Neubauer Heinrich , Schmoock Gernot , Grossmann Ernst , Seyboldt Christian
Published: May 2013

This study provides data on the distribution and relationship of C. difficile PCR ribotypes in diarrhoeic calves in Germany. C. difficile was isolated from 176 of 999 (17.6 %) faecal samples or swabs of diarrhoeic calves from 603 farms collected between January 2010 and August 2012 by eight federal laboratories of six states. Strains were assigned to 17 PCR ribotypes. PCR ribotypes 033 (57 %), 078 (17 %) and 045/FLI01 (closest match to 045 in the WEBRIBO database; 9 %) were found the most frequently. Nine per cent of all culture-positive tested animals shed more than one multiple locus variable number tandem repeat analysis (MLVA) or PCR ribotype. Eight PCR ribotypes with related profiles (including 033, 078 and 045/FLI01) representing 92 % of all isolates were grouped into three clusters. Molecular relatedness was supported by the absence of the MLVA locus A6
Cd
only in clustered strains and identical toxin gene profiles for strains within each cluster. Previously reported mulitilocus sequence typing analysis for PCR ribotypes that were also recovered in this study found identical sequence types and a tcdC deletion (Δ39 bp) for 033, 045, 078 and 126 (ST-11), confirming this clustering. A different geographical occurrence of PCR ribotypes was shown for cluster 033 (found more frequently in southern Germany) and 045 (found more frequently in northern Germany). This study showed that clusters of C. difficile PCR ribotypes related to 033, 078 and 045 are predominant in diarrhoeic calves in Germany. The high number of strains belonging to PCR ribotype 078 demonstrated that diarrhoeic calves are also potential reservoirs for human pathogenic C. difficile strains.
Prevalence of fusB in Staphylococcus aureus clinical isolates
Authors: Huang Jinwei , Ye Meiping , Ding Hui , Guo Qinglan , Ding Baixing , Wang Minggui
Published: May 2013

Fusidic acid (FA) resistance in Staphylococcus aureus markedly varied among different regions. Few data for FA resistance are available in China. In this study, FA susceptibility testing was performed, and the prevalence of fusB and fusC in 116 clinical isolates of S. aureus was investigated by PCR. Mutations in fusA were also determined by sequencing of PCR products. Molecular typing of fusB-positive strains was based on multilocus sequence typing (MLST), spa typing and pulsed-field gel electrophoresis (PFGE). A DNA fragment flanking fusB was sequenced. Transformation experiments were carried out in fusB-positive S. aureus. Of 116 S. aureus including 19 meticillin-resistant S. aureus (MRSA) and 97 meticillin-susceptible S. aureus (MSSA), four (3.5 %) were resistant to FA with MICs of 6–12 µg ml−1, including one MRSA from blood and three MSSA from wound exudates. All four FA-resistant isolates were found to be fusB gene positive. Three FA-resistant MSSA strains had the same MLST profile of ST630 and spa type of t377, whilst the MRSA strain belonged to ST630-t4549. Only one PFGE pattern was recognized for these four strains. No fusC and fusA mutations were detected in any of the isolates. FA resistance in fusB-positive clinical isolates could be transferred to S. aureus RN4220. The fusB gene was located in a transposon-like element, which had 99 % identity with that found in pUB101. In conclusion, the FA resistance rate is low in S. aureus, and the fusB gene is responsible for the resistance.
Anisotropic thermal expansion of Lan(Ti,Fe)nO3n+ 2(n= 5 and 6)
Authors: Wölfel Alexander , Dorscht Philipp , Lichtenberg Frank , van Smaalen Sander
Published: May 2013

Crystal structures are reported for two perovskite-related compounds with nominal compositions La5(Ti0.8Fe0.2)5O17and La6(Ti0.67Fe0.33)6O20at seven different temperatures between 90 and 350 K. For both compounds no evidence of a structural phase transition in the investigated range of temperatures was found. The thermal expansions are found to be anisotropic, with the largest thermal expansion along a direction parallel to the slabs of these layered compounds. The origin of this anisotropy is proposed to be a temperature dependence of tilts of the octahedral (Ti,Fe)O6groups. It is likely that the same mechanism will determine similar anisotropic thermal behaviour of other compoundsAnBnO3n + 2. The crystal structures have revealed partial chemical order of Ti/Fe over theBsites, with iron concentrated towards the centers of the slabs. Local charge compensation is proposed as the driving force for the chemical order, where the highest-valent cation moves to sites near the oxygen-rich borders of the slabs. A linear dependence on the site occupation fraction by Fe of the computed valences leads to extrapolated valence values close to the formal valence of Ti4+for sites fully occupied by Ti, and of Fe3+for sites fully occupied by Fe. These results demonstrate the power of the bond-valence method, and they show that refined oxygen positions are the weighted average of oxygen positions in TiO6and FeO6octahedral groups.
Electron densities by the maximum entropy method (MEM) for various types of prior densities: a case study on three amino acids and a tripeptide
Authors: Prathapa Siriyara Jagannatha , Mondal Swastik , van Smaalen Sander
Published: May 2013

Dynamic model densities according to Mondalet al.[(2012),Acta Cryst.A68, 568–581] are presented for independent atom models (IAM), IAMs after high-order refinements (IAM-HO), invariom (INV) models and multipole (MP) models of α-glycine, DL-serine, L-alanine and Ala–Tyr–Ala atT≃ 20 K. Each dynamic model density is used as prior in the calculation of electron density according to the maximum entropy method (MEM). We show that at the bond-critical points (BCPs) of covalent C—C and C—N bonds the IAM-HO and INV priors produce reliable MEM density maps, including reliable values for the density and its Laplacian. The agreement between these MEM density maps and dynamic MP density maps is less good for polar C—O bonds, which is explained by the large spread of values of topological descriptors of C—O bonds in static MP densities. The density and Laplacian at BCPs of hydrogen bonds have similar values in MEM density maps obtained with all four kinds of prior densities. This feature is related to the smaller spatial variation of the densities in these regions, as expressed by small magnitudes of the Laplacians and the densities. It is concluded that the use of the IAM-HO prior instead of the IAM prior leads to improved MEM density maps. This observation shows interesting parallels to MP refinements, where the use of the IAM-HO as an initial model is the accepted procedure for solving MP parameters. A deconvolution of thermal motion and static density that is better than the deconvolution of the IAM appears to be necessary in order to arrive at the best MP models as well as at the best MEM densities.
Niche marketing research: status and challenges
Authors: Toften Kjell , Hammervoll Trond
Published: May 2013

Purpose

The purpose of this paper is to present a concise status of niche marketing research and thereby provide a basis for further scholarly enhancement and insights for practitioners.

Design/methodology/approach

This paper takes the form of a literature review.

Findings

Reasons for why and when to pursue niche marketing, key success factors for implementing niche marketing and the potential problem areas are identified. Avenues for advancing knowledge about niche marketing are discussed.

Research limitations/implications

Practitioners benefit from this comprehensive review of findings and insights from previous research. Scholars benefit from this review, as it summarizes and identifies key areas for future niche marketing research.

Originality/value

There has be no known scholarly article assessing the status of niche marketing research since Dalgic and Leeuw's seminal work.
Making sense of Enterprise 2.0
Authors: Gardner Ben
Published: May 2013

Purpose

The purpose of this paper is to demonstrate how the capabilities of Enterprise 2.0 tools align to the tasks knowledge workers perform. The objective is to provide knowledge workers and information architects with a framework that enables the development of a suite of Enterprise 2.0 tools in support of knowledge management across the full knowledge lifecycle.

Design/methodology/approach

The capabilities of Enterprise 2.0 tools were mapped against the requirements associated with each of the four main domains (chaotic, complex, knowable and known) of the Cynefin framework.

Findings

The Cynefin model provides a useful framework for illustrating how the various tools within an Enterprise 2.0 suite support the different activities/tasks knowledge workers perform. Aligning Enterprise 2.0 tools based on the domain requirements of the Cynefin model allows the classification of these capabilities based on a task‐based framework rather than the traditional feature/function‐based ones.

Practical implications

Application of this framework will help knowledge workers and information architects understand the relationship between technical capabilities and business tasks. This understanding will help both in tool selection with respect to business problem (architects) and also provide clarity of purpose in support of change management/adoption (knowledge workers).

Originality/value

Much of the literature around understanding Enterprise 2.0 tools has focused on a classical feature/function classification. The analysis presented here provides a classification based on the Cynefin model of knowledge creation. This classification model provides a valuable tool to those interested in developing environments that enable collaboration and knowledge generation/capture using these capabilities.
Learning at transition for new and experienced staff
Authors: Milligan Colin , Margaryan Anoush , Littlejohn Allison
Published: May 2013

Purpose

This study aims to improve the understanding of the learning and development that occurs during initial and subsequent role transitions within knowledge intensive workplaces.

Design/methodology/approach

Semi‐structured interviews were conducted with 19 knowledge workers in a multinational company and the learning experiences of new graduates contrasted with those of more experienced workers who had recently joined or changed role within the organization.

Findings

Graduate recruits and more experienced workers utilise a similar range of learning approaches, favouring a combination of traditional formal learning, learning by doing and learning with and from others, but differ in the precise modes and strategies used. It was found that graduate induction provides appropriate support for initial transition into the workplace, but that experienced workers undergoing subsequent career transitions do not receive similar socialization support despite encountering similar challenges.

Research limitations/implications

This study brings concepts and literature from two distinct research traditions together to explore learning during transition. In doing so, the impact of organizational socialization strategies as a mechanism by which an environment to support rich learning is created can be seen. The study was exploratory in nature, examining only one organization and studying a relatively small group of workers.

Originality/value

While employee induction has been studied in detail, the learning occurring at this time, and particularly during subsequent career transitions, is less well understood. This article is of value to those investigating learning in knowledge intensive workplaces, as well as human resource managers responsible for socialization of employees entering new roles.