bluuebunny/crossref_metadata_2025 huggingface dataset:
Meticillin-resistant Staphylococcus aureus bacteraemia
Authors: Price James , Llewelyn Martin
Published: July 2014

Although rates of MRSA bacteraemia have fallen markedly in the UK, S. aureus bacteraemia remains a common clinical entity associated with substantial morbidity and mortality. This case illustrates the key elements of optimal management. Early diagnosis and prompt initiation of treatment are crucial. Unless the infection is known to be caused by MRSA, treatment should include a beta-lactam drug where possible. It is not established whether using combination antibiotic therapy improves outcome. Foci of infection must be identified promptly by thorough and repeated clinical examination and radiological investigation and removed as soon as possible. Current best evidence indicates that patients with S. aureus bacteraemia should receive intravenous treatment for a minimum of 2 weeks, with this duration increasing to 4–6 weeks in patients with endocarditis or unremovable foci of infection.
Urinary sepsis: vancomycin-resistant enterococci
Authors: Howard Julia , Soleimanian Sorrush
Published: July 2014

Enterococci spp including vancomycin-resistant enterococci (VRE) are low virulence organisms; however, treatment options are limited and so treatment of invasive infection can cause management issues. Enterococci are resident in the gastrointestinal (GI) tract and most commonly cause infection originating in the GI or urinary tracts. Bacteraemia may lead to the spread of infection to other sites including, rarely, the heart valves, leading to infective endocarditis. This chapter highlights a case of VRE bacteraemia associated with pyonephrosis in which removal of the source (drainage of pus) was the most important intervention. Classification by microbiology, epidemiology, and antibiotic choices for VRE infections are also discussed.
Disseminated nocardiosis
Authors: Arnold Amber , Ellis Jayne , Hill Robert
Published: July 2014

Disseminated nocardiosis classically occurs in immunosuppressed individuals. Infection commonly enters via the respiratory route but may also occur through skin trauma. A case of disseminated nocardiosis in an immunosuppressed individual is presented. The case highlights challenges surrounding diagnosis and microbiological identification of Gram-positive branching bacilli, patient management, and choice of antibiotics. The common side effects of co-trimoxazole are discussed.
Urinary sepsis: extended spectrum β-lactamase-producing E. coli
Authors: Dhillon Rishi , Arnold Amber , Donaldson Hugo
Published: July 2014

Antibiotic resistance in Gram-negative organisms is increasing. Empirical antibiotic prescribing policies are based on local epidemiology. This chapter highlights a case of urinary sepsis due to an extended spectrum beta-lactamase (ESBL)-producing E. coli. The patient in the case is treated with the empirical antibiotic choice and dies. The microbiological identification and treatment of ESBL-producing organisms is discussed in reference to the correlation of in vitro susceptibility data with in vivo response. The role of beta-lactam-beta-lactamase inhibitor combinations (BLBLI) in vitro and the use of carbapenems for these organisms is discussed.
Treated pulmonary tuberculosis complicated by sarcoidosis
Authors: Russell Georgina , O’Connor Sally , Chua Felix
Published: July 2014

Sarcoidosis is a granulomatous disease of unknown aetiology which has a broad differential diagnosis. The condition is known to occur in patients with a previous history of treated tuberculosis, as occurs in the case presented. The diagnosis using biopsy and histology, management, and possible causes are discussed.
Practice management
Authors: Simon Chantal , Everitt Hazel , van Dorp Françoise , Burkes Matt
Published: July 2014

GPs as managers

Practice staff

GP premises

Computers and classification

Useful websites for GPs

Eligibility for free healthcare

Registration and practice leaflets

The primary healthcare team

Confidentiality

Consent

Complaints

Removal from the practice list

‘If you have time to do something wrong; you have time to do it right’...
Gastrointestinal medicine
Authors: Simon Chantal , Everitt Hazel , van Dorp Françoise , Burkes Matt
Published: July 2014

Assessment of abdominal pain

Vomiting and diarrhoea

Constipation

Other abdominal symptoms and signs

Dyspepsia and H. pylori

Oesophageal conditions

Gastro-oesophageal reflux and gastritis

Peptic ulceration

Gastro-oesophageal malignancy

Hernias

Appendicitis and small bowel disease

Colorectal cancer screening

Colorectal cancer

Other large bowel conditions

Anal and perianal problems...
Renal medicine and urology
Authors: Simon Chantal , Everitt Hazel , van Dorp Françoise , Burkes Matt
Published: July 2014

Creatinine, urea, and electrolytes

Presentation of renal disease

Renal failure

Kidney diseases

Renal stones

Haematuria, bladder and renal cancer

Urinary tract infection

Incontinence of urine

Aids and appliances for incontinence

Urinary tract obstruction

Benign prostatic hypertrophy

Prostate cancer

Treatment of prostate cancer

Conditions of the penis...
Neurology
Authors: Simon Chantal , Everitt Hazel , van Dorp Françoise , Burkes Matt
Published: July 2014

Reflexes and muscle power

Cranial nerve lesions

Neuropathy

Polyneuropathy

Walking problems

Other movement problems

Speech problems

Fits, faints, and funny turns

Assessment of headache

Migraine

Other headaches and facial pain

Raised intracranial pressure

Intracranial bleeds

Acute stroke

Secondary prevention of stroke

Parkinsonism and Parkinson’s disease...
Infectious disease
Authors: Simon Chantal , Everitt Hazel , van Dorp Françoise , Burkes Matt
Published: July 2014

Immunization

Symptoms, signs, and notification of infectious disease

Illness in returning travellers

Infections in immunocompromised patients

Childhood viral infections

Streptococcal and staphylococcal infections

Other bacterial infections

• Active immunity Induced using inactivated or attenuated live organisms or their products. Acts by inducing cell-mediated immunity and serum antibodies. Generally long-lasting...
Ear, nose, and throat
Authors: Simon Chantal , Everitt Hazel , van Dorp Françoise , Burkes Matt
Published: July 2014

The mouth

Dental and jaw problems

Sore throat

Hoarseness and stridor

Neck lumps and salivary gland problems

Nasal problems

Sinusitis and rhinitis

Earache and external ear problems

Otitis media

Deafness

Tinnitus and vertigo

To exclude malignancy, ALL:

• Mouth ulcers persisting for >3wk

• Lumps in the mouth persisting >3wk...
Ophthalmology
Authors: Simon Chantal , Everitt Hazel , van Dorp Françoise , Burkes Matt
Published: July 2014

‘The eye is the window of the mind’

Richard II, William Shakespeare (1564–1616)

Assessment of the eye

Eye trauma

Eye pain, papilloedema, and orbital disease

Lid disease

Blepharitis and tear duct problems

The red eye and conjunctivitis

Corneal, sclera, and uveal disease

Visual field loss and blindness...
Case 1.2
Authors: Lee Christine U. , Glockner James F.
Published: July 2014

66-year-old woman with nausea, vomiting, and abdominal pain after a recent fundoplication. Abdominal CT revealed a right hepatic lobe mass

Coronal SSFSE (Figure 1.2.1) and axial fat-suppressed FSE T2-weighted (Figure 1.2.2) images demonstrate a lobulated mass with high signal intensity in the right hepatic lobe. Axial arterial phase, portal venous phase, and coronal oblique reformatted equilibrium phase postgadolinium 3D SPGR images (...
Case 1.3
Authors: Lee Christine U. , Glockner James F.
Published: July 2014

70-year-old woman with nausea and weakness, elevated liver function tests, and elevated white blood cell count

Axial fat-saturated FSE (Figure 1.3.1) and SSFP (Figure 1.3.2) images demonstrate a large heterogeneous, predominantly cystic lesion in the right hepatic lobe containing multiple thick septations. Note the internal fluid-fluid levels, better seen on the SSFP image. Axial postgadolinium arterial, portal venous, and equilibrium phase images (...
Case 1.4
Authors: Lee Christine U. , Glockner James F.
Published: July 2014

67-year-old woman status post fundoplication 2 months ago, with development of fever and nonproductive cough shortly afterward; laboratory tests revealed normal liver function and an increased neutrophil count

Coronal SSFSE image (Figure 1.4.1) and axial fat-suppressed T2-weighted FSE image (Figure 1.4.2...
Case 1.6
Authors: Lee Christine U. , Glockner James F.
Published: July 2014

3-year-old girl with an enlarging abdomen

Axial fat-suppressed FSE T2-weighted (Figure 1.6.1) and coronal T1-weighted (Figure 1.6.2) and T2-weighted (Figure 1.6.3) images demonstrate a large, well-circumscribed mixed solid and cystic mass occupying the entire left hepatic lobe. Axial postgadolinium 2D SPGR images (...
Case 1.7
Authors: Lee Christine U. , Glockner James F.
Published: July 2014

75-year-old man with right upper quadrant pain

Axial fat-suppressed dual echo FSE T2-weighted images (Figure 1.7.1) reveal a lobulated mass in the right hepatic lobe with diffuse high signal intensity. Note that on the dual echo images, there is little signal loss between the first (TE, 80 ms) and second (TE, 160 ms) echoes. Axial arterial, portal venous, equilibrium, and 5-minute delayed phase postgadolinium 3D SPGR images (...
Case 1.10
Authors: Lee Christine U. , Glockner James F.
Published: July 2014

59-year-old woman who presents for a second opinion of well-differentiated HCC that was biopsy proven elsewhere

Axial fat-suppressed FSE T2-weighted images (Figure 1.10.1) demonstrate a lesion in the posterior right hepatic lobe with central hyperintensity surrounded by smaller foci of similar high signal intensity. Axial arterial, portal venous, and equilibrium phase postgadolinium 3D SPGR images (...
Saccharopolyspora halotolerans sp. nov., a halophilic actinomycete isolated from a hypersaline lake
Authors: Lv Ling-Ling , Zhang Yue-Feng , Xia Zhan-Feng , Zhang Jing-Jing , Zhang Li-Li
Published: July 2014

A novel actinomycete strain, designated TRM 45123T, was isolated from a hypersaline habitat in Xinjiang Province (40° 20′ N 90° 49′ E), north-west China. The isolate was characterized using a polyphasic approach. 16S rRNA gene sequence analysis indicated that strain TRM 45123T belonged to the genus

Saccharopolyspora

and was closely related to

Saccharopolyspora gloriosae

(96.7 % similarity). The G+C content of the DNA was 69.07 mol%. The isolate contained meso-diaminopimelic acid as the diagnostic diamino acid, and arabinose and ribose as the major whole-cell sugars. The diagnostic phospholipids were phosphatidylethanolamine, phosphatidylcholine and phosphatidylglycerol. The predominant menaquinone was MK-9(H4). The major fatty acids were iso-C16 : 0, anteiso-C17 : 0, iso-C15 : 0 and anteiso-C15 : 0. On the basis of the evidence from this polyphasic study, a novel species, Saccharopolyspora
halotolerans sp. nov., is proposed. The type strain of Saccharopolyspora
halotolerans is TRM 45123T ( = CCTCC AA 2013006T = DSM 45990T).
Description of Propionispira arcuata sp. nov., isolated from a methanogenic reactor of cattle waste, reclassification of Zymophilus raffinosivorans and Zymophilus paucivorans as Propionispira
raffinosivorans comb. nov. and Propionispira paucivorans comb. nov. and emended description of the genus Propionispira
Authors: Ueki Atsuko , Watanabe Misa , Ohtaki Yoshimi , Kaku Nobuo , Ueki Katsuji
Published: July 2014

A strictly anaerobic bacterial strain, WK011T, was isolated from a methanogenic reactor treating waste from cattle farms. The cells stained Gram-negative and were curved rods with a polar or subpolar flagellum. Spore formation was not observed. The optimum temperature for growth was 35 °C and the optimum pH was 6.7. Tests for oxidase, catalase and nitrate-reduction activities were negative. Hydrogen sulfide was produced. The strain fermented carbohydrates and produced acetate and propionate as major fermentation products. The genomic DNA G+C content was 41.7 mol%. The major cellular fatty acids were C15 : 0, C16 : 1ω9c and C18 : 1 dimethylacetal. The diagnostic diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid. The most closely related species to strain WK011T on the basis of 16S rRNA gene sequences were

Propionispira arboris

and

Zymophilus raffinosivorans

(95.6 % sequence similarity to the type strains of both species). It was shown by phylogenetic and phenotypic examination of the type strains of related species, including the second species of the genus

Zymophilus

,

Zymophilus paucivorans

, that the two genera should be combined and that the two species of the genus

Zymophilus

should be transferred to the genus

Propionispira,
as Propionispira
raffinosivorans comb. nov. (type strain SH2T = ATCC 49691T = DSM 20765T) and Propionispira paucivorans comb. nov. (type strain AA1T = ATCC 49689T = DSM 20756T), with an emended description of the genus

Propionispira

. Based on differences in the phylogenetic and phenotypic characteristics of strain WK011T from those of closely related species, the novel species Propionispira arcuata sp. nov. is proposed to accommodate the strain. The type strain is WK011T ( = JCM 16475T = DSM 22929T).
Structure and gene cluster of the O antigen of Escherichia coli L-19, a candidate for a new O-serogroup
Authors: Zdorovenko Evelina L. , Varbanets Lyudmila D. , Liu Bin , Valueva Olga A. , Wang Quan , Shashkov Alexander S. , Garkavaya Ekaterina G. , Brovarskaya Oksana S. , Wang Lei , Knirel Yuriy A.
Published: July 2014

Escherichia coli L-19 isolated from a healthy individual did not agglutinate with any of 21 polyvalent antisera that cover 174 E. coli O-serogroups. The strain was studied in respect to the O-antigen (O-specific polysaccharide, OPS) structure and genetics. The LPS was isolated by phenol–water extraction of bacterial cells and cleaved by mild acid hydrolysis to yield the OPS. The OPS was studied by sugar and methylation analyses, along with 1D and 2D 1H and 13C NMR spectroscopy. The established structure of the linear tetrasaccharide repeating unit was found to be unique among known bacterial polysaccharide structures. A peculiar component of the L-19 OPS was an amide of glucuronic acid with 2-amino-1,3-propanediol (2-amino-2-deoxyglycerol) (GroN). The O-antigen gene cluster of L-19 between the conserved genes galF and gnd was sequenced, and gene functions were tentatively assigned by a comparison with sequences in the available databases and found to be in agreement with the OPS structure. Except for putative genes for synthesis and transfer of GroN, the sequences in the L-19 O-antigen gene cluster were little related to those of reference strains of the 174 known E. coli O-serogroups. The data obtained suggest that L-19 can be considered as a candidate for a new E. coli O-serogroup.
Null Models for Community Detection in Spatially-Embedded, Temporal Networks
Authors: Sarzynska Marta , Leicht Elizabeth A. , Chowell Gerardo , Porter Mason A.
Published: July 2014

In the study of networks, it is often insightful to use algorithms to determine mesoscale features such as “community structure”, in which densely connected sets of nodes constitute “communities” that have sparse connections to other communities. The most popular way of detecting communities algorithmically is to optimize the quality function known as modularity. When optimizing modularity, one compares the actual connections in a (static or time-dependent) network to the connections obtained from a random-graph ensemble that acts as a null model. The communities are then the sets of nodes that are connected to each other densely relative to what is expected from the null model. Clearly, the process of community detection depends fundamentally on the choice of null model, so it is important to develop and analyze novel null models that take into account appropriate features of the system under study. In this paper, we investigate the effects of using null models that take incorporate spatial information, and we propose a novel null model based on the radiation model of population spread. We also develop novel synthetic spatial benchmark networks in which the connections between entities are based on distance or flux between nodes, and we compare the performance of both static and time-dependent radiation null models to the standard (“Newman-Girvan”) null model for modularity optimization and a recently-proposed gravity null model. In our comparisons, we use both the above synthetic benchmarks and time-dependent correlation networks that we construct using countrywide dengue fever incidence data for Peru. We also evaluate a recently-proposed correlation null model, which was developed specifically for correlation networks that are constructed from time series, on the epidemic-correlation data. Our findings underscore the need to use appropriate generative models for the development of spatial null models for community detection.

PACS numbers

87.19.Xx,89.20.-a,89.75.Fb,05.45.Tp
Weak protein–cationic co-ion interactions addressed by X-ray crystallography and mass spectrometry
Authors: Bénas Philippe , Auzeil Nicolas , Legrand Laurent , Brachet Franck , Regazzetti Anne , Riès-Kautt Madeleine
Published: July 2014

The adsorption of Rb+, Cs+, Mn2+, Co2+and Yb3+onto the positively charged hen egg-white lysozyme (HEWL) has been investigated by solving 13 X-ray structures of HEWL crystallized with their chlorides and by applying electrospray ionization mass spectrometry (ESI-MS) first to dissolved protein crystals and then to the protein in buffered salt solutions. The number of bound cations follows the order Cs+< Mn2+≃ Co2+< Yb3+at 293 K. HEWL binds less Rb+(qtot= 0.7) than Cs+(qtot= 3.9) at 100 K. Crystal flash-cooling drastically increases the binding of Cs+, but poorly affects that of Yb3+, suggesting different interactions. The addition of glycerol increases the number of bound Yb3+cations, but only slightly increases that of Rb+. HEWL titrations with the same chlorides, followed by ESI-MS analysis, show that only about 10% of HEWL binds Cs+and about 40% binds 1–2 Yb3+cations, while the highest binding reaches 60–70% for protein binding 1–3 Mn2+or Co2+cations. The binding sites identified by X-ray crystallography show that the monovalent Rb+and Cs+preferentially bind to carbonyl groups, whereas the multivalent Mn2+, Co2+and Yb3+interact with carboxylic groups. This work elucidates the basis of the effect of the Hofmeister cation series on protein solubility.
HermiteFit: fast-fitting atomic structures into a low-resolution density map using three-dimensional orthogonal Hermite functions
Authors: Derevyanko Georgy , Grudinin Sergei
Published: July 2014

HermiteFit, a novel algorithm for fitting a protein structure into a low-resolution electron-density map, is presented. The algorithm accelerates the rotation of the Fourier image of the electron density by using three-dimensional orthogonal Hermite functions. As part of the new method, an algorithm for the rotation of the density in the Hermite basis and an algorithm for the conversion of the expansion coefficients into the Fourier basis are presented.HermiteFitwas implemented using the cross-correlation or the Laplacian-filtered cross-correlation as the fitting criterion. It is demonstrated that in the Hermite basis the Laplacian filter has a particularly simple form. To assess the quality of density encoding in the Hermite basis, an analytical way of computing the crystallographicRfactor is presented. Finally, the algorithm is validated using two examples and its efficiency is compared with two widely used fitting methods,ADP_EMandcoloresfrom theSituspackage.HermiteFitwill be made available at http://nano-d.inrialpes.fr/software/HermiteFit or upon request from the authors.
Structural and biophysical analysis of interactions between cod and human uracil-DNAN-glycosylase (UNG) and UNG inhibitor (Ugi)
Authors: Assefa Netsanet Gizaw , Niiranen Laila , Johnson Kenneth A. , Leiros Hanna-Kirsti Schrøder , Smalås Arne Oskar , Willassen Nils Peder , Moe Elin
Published: July 2014

Uracil-DNAN-glycosylase from Atlantic cod (cUNG) shows cold-adapted features such as high catalytic efficiency, a low temperature optimum for activity and reduced thermal stability compared with its mesophilic homologue human UNG (hUNG). In order to understand the role of the enzyme–substrate interaction related to the cold-adapted properties, the structure of cUNG in complex with a bacteriophage encoded natural UNG inhibitor (Ugi) has been determined. The interaction has also been analyzed by isothermal titration calorimetry (ITC). The crystal structure of cUNG–Ugi was determined to a resolution of 1.9 Å with eight complexes in the asymmetric unit related through noncrystallographic symmetry. A comparison of the cUNG–Ugi complex with previously determined structures of UNG–Ugi shows that they are very similar, and confirmed the nucleotide-mimicking properties of Ugi. Biophysically, the interaction between cUNG and Ugi is very strong and shows a binding constant (Kb) which is one order of magnitude larger than that for hUNG–Ugi. The binding of both cUNG and hUNG to Ugi was shown to be favoured by both enthalpic and entropic forces; however, the binding of cUNG to Ugi is mainly dominated by enthalpy, while the entropic term is dominant for hUNG. The observed differences in the binding properties may be explained by an overall greater positive electrostatic surface potential in the protein–Ugi interface of cUNG and the slightly more hydrophobic surface of hUNG.
Domain mobility as probed by small-angle X-ray scattering may account for substrate access to the active site of two copper-dependent amine oxidases
Authors: Dainese Enrico , Sabatucci Annalaura , Pintus Francesca , Medda Rosaria , Angelucci Clotilde Beatrice , Floris Giovanni , Maccarrone Mauro
Published: July 2014

Amine oxidases are a family of dimeric enzymes that contain one copper(II) ion and one 2,4,5-trihydroxyphenyalanine quinone per subunit. Here, the low-resolution structures of two Cu/TPQ amine oxidases from lentil (Lens esculenta) seedlings and fromEuphorbia characiaslatex have been determined in solution by small-angle X-ray scattering. The active site of these enzymes is highly buried and requires a conformational change to allow substrate access. The study suggests that the funnel-shaped cavity located between the D3 and D4 domains is narrower within the crystal structure, whereas in solution the D3 domain could undergo movement resulting in a protein conformational change that is likely to lead to easier substrate access.
Structural and dynamic changes associated with beneficial engineered single-amino-acid deletion mutations in enhanced green fluorescent protein
Authors: Arpino James A. J. , Rizkallah Pierre J. , Jones D. Dafydd
Published: July 2014

Single-amino-acid deletions are a common part of the natural evolutionary landscape but are rarely sampled during protein engineering owing to limited and prejudiced molecular understanding of mutations that shorten the protein backbone. Single-amino-acid deletion variants of enhanced green fluorescent protein (EGFP) have been identified by directed evolution with the beneficial effect of imparting increased cellular fluorescence. Biophysical characterization revealed that increased functional protein production and not changes to the fluorescence parameters was the mechanism that was likely to be responsible. The structure EGFPD190Δcontaining a deletion within a loop revealed propagated changes only after the deleted residue. The structure of EGFPA227Δrevealed that a `flipping' mechanism was used to adjust for residue deletion at the end of a β-strand, with amino acids C-terminal to the deletion site repositioning to take the place of the deleted amino acid. In both variants new networks of short-range and long-range interactions are generated while maintaining the integrity of the hydrophobic core. Both deletion variants also displayed significant local and long-range changes in dynamics, as evident by changes inBfactors compared with EGFP. Rather than being detrimental, deletion mutations can introduce beneficial structural effects through altering core protein properties, folding and dynamics, as well as function.
4-[(5-Bromo-2-hydroxybenzylidene)amino]-3-ethyl-1H-1,2,4-triazole-5(4H)-thione
Authors: Yuan Cai-Xia , Lan Shu-Fen , Liu Xin-Yu , Zhu Miao-Li
Published: July 2014

The title compound, C11H11BrN4OS, crystallized as a racemic twin with two symmetry-independent molecules in the asymmetric unit. The dihedral angles between the benzene and triazole rings of the two independent molecules are 56.41 (18) and 54.48 (18)°. An intramolecular O—H...N hydrogen bond occurs in each molecule. In the crystal, pairs of symmetry-independent molecules are linked by pairs of almost linear N—H...S hydrogen bonds, forming cyclic dimers characterized by anR22(8) motif. There are weak π–π interactions between the benzene rings of symmetry-independent molecules, with a centroid–centroid distance of 3.874 (3) Å.
The university press: trends, initiatives and collaborations over the past several years
Authors: Hayes Clayton , P. Holley Robert
Published: July 2014

Purpose

– The purpose of this paper is to examine recent trends that have affected university presses (UPs). The increased reliance on digital resources and fiscal constraints within higher education has forced UPs to re-evaluate their position with the scholarly communication system. Responses include an increased focus on partnerships, new forms of publication, changing business models and better meeting customers’ needs.

Design/methodology/approach

– The authors have reviewed publications on UPs from the past five years and added their viewpoints on current and future trends.

Findings

– UPs must adapt to resource scarcity and current trends in scholarly communication to remain viable.

Practical implications

– Both UPs and academic libraries may gain insights on how to meet the needs of researchers and scholars within a changing environment.

Originality/value

– This paper summarizes and evaluates a broad spectrum of research on UPs.
Distorted constriction contact resistance between clamped slabs
Authors: A. Cividjian Grigore
Published: July 2014

Purpose

– The purpose of this paper is the more exact evaluation of distorted constriction contact resistance between two clamped slabs or thin films, having a bi-dimensional current lines structure.

Design/methodology/approach

– Mathematical modeling using conformal mappings.

Findings

– The influence of the tarnish film on the distorted constriction resistance is clarified and three new exact formulas are proposed for the distorted constriction resistance between clamped slabs with rectangular contact spot. Comparisons with early proposed formula for constriction resistance of slab narrowing and with finite element analysis results are presented.

Research limitations/implications

– The research is limited to direct current and homogeneous and isotropic media and the results can be extended at alternate current when the skin effect is negligible.

Practical implications

– Exact evaluation of 2D constriction contact resistance which appears in macro-scale contacts electrical equipment and in MEMS devices, particularly in crimp contacts.

Originality/value

– The proposed formulas are new, original, simple and exact.
Efficient evaluation of the earth return mutual impedance of overhead conductors over a horizontally multilayered soil
Authors: Lee Jae-bok , Zou Jun , Li Benliang , Ju Munno
Published: July 2014

Purpose

– The per-unit-length earth return mutual impedance of the overhead conductors plays an important role for analyzing electromagnetic transients or couplings of multi-conductor systems. It is impossible to have a closed-form expression to evaluate this kind of impedance. The purpose of this paper is to propose an efficient numerical approach to evaluate the earth return mutual impedance of the overhead conductors above horizontally multi-layered soils.

Design/methodology/approach

– The expression of the earth return mutual impedance, which contains a complex highly oscillatory semi-infinite integral, is divided into two parts intentionally, i.e. the definite and the tail integral, respectively. The definite integral is calculated using the proposed moment functions after fitting the integrand into the piecewise cubic spline functions, and the tail integral is replaced by exponential integrals with newly developed asymptotic integrands.

Findings

– The numerical examples show the proposed approach has a satisfactory accuracy for different parameter combinations. Compared to the direct quadrature approach, the computational time of the proposed approach is very competitive, especially, for the large horizontal distance and the low height of the conductors.

Originality/value

– The advantage of the proposed approach is that the calculation of the highly oscillatory integral is completely avoided due to the fact that the moment function can be evaluated analytically. The contribution of the tail integral is well included by means of the exponential integral, though in an asymptotic way. The proposed approach is completely general, and can be applied to calculate the earth return mutual impedance of overhead conductors above a soil structure with an arbitrary number of horizontal layers.
An efficient algorithm for a certain class of robust optimization problems
Authors: Paffrath M. , Wever U.
Published: July 2014

Purpose

– The purpose of this paper is to present an efficient method for the numerical treatment of robust optimization problems with absolute reliability constraints.

Design/methodology/approach

– Optimization with anti-optimization based on response surface techniques; polynomial chaos for approximation of the stochastic objective function.

Findings

– The number of function calls is comparable to that of the corresponding deterministic problem. Thus, the method is well suited for complex technical systems. The performance of the method is demonstrated on an optimal design problem for turbochargers.

Originality/value

– The highlights of this paper are: algorithms for robust and deterministic problems show comparable complexity; no derivatives required; good convergence properties because of special set up of optimization problem; application in complex industrial examples.
Analyzing distortion contributions in a complex device model
Authors: Rahkonen Timo , P. Aikio Janne
Published: July 2014

Purpose

– The purpose of this paper is to propose a method to reduce the non-linear distortion of a transistor to its input and output ports to aid distortion contribution analysis (DCA). This is especially needed when the internal structure of a device model is complex.

Design/methodology/approach

– The non-linear distortion generated by all non-linear sources inside a device model are reduced to transistor i/o ports by LMSE fitting techniques. Simulations of an LDMOS power transistor are used to compare the reduced distortion results with the actual non-linear sources.

Findings

– It is shown, that device models where the current sources are split by intermediate nodes cause superficial results, when distortion contributions are calculated as a superposition of contributions from individual non-linear sources. The proposed iterative fitting technique works.

Research limitations/implications

– Some non-quasistatic effects and the transfer functions from external terminals to internal controlling nodes are not covered.

Practical implications

– The analysis is a step toward a generic non-linear distortion contribution simulation tool that would aid the designers to develop more linear analog circuits.

Originality/value

– The concept of DCA itself is fairly new. This paper makes a step to represent the distortion sources in a canonical way.
Robust DC and efficient time-domain fast fault simulation
Authors: Tasic Bratislav , J. Dohmen Jos , Jan W. ter Maten E. , G.J. Beelen Theo , H.A. Schilders Wil , de Vries Alex , van Beurden Maikel
Published: July 2014

Purpose

– Imperfections in manufacturing processes may cause unwanted connections (faults) that are added to the nominal, “golden”, design of an electronic circuit. By fault simulation one simulates all situations. Normally this leads to a large list of simulations in which for each defect a steady-state (direct current (DC)) solution is determined followed by a transient simulation. The purpose of this paper is to improve the robustness and the efficiency of these simulations.

Design/methodology/approach

– Determining the DC solution can be very hard. For this the authors present an adaptive time-domain source stepping procedure that can deal with controlled sources. The method can easily be combined with existing pseudo-transient procedures. The method is robust and efficient. In the subsequent transient simulation the solution of a fault is compared to a golden, fault-free, solution. A strategy is developed to efficiently simulate the faulty solutions until their moment of detection.

Findings

– The paper fully exploits the hierarchical structure of the circuit in the simulation process to bypass parts of the circuit that appear to be unaffected by the fault. Accurate prediction and efficient solution procedures lead to fast fault simulation.

Originality/value

– The fast fault simulation helps to store a database with detectable deviations for each fault. If such a detectable output “matches” a result of a product that has been returned because of malfunctioning it helps to identify the subcircuit that may contain the real fault. One aims to detect as much as possible candidate faults. Because of the many options the simulations must be very efficient.
Multiscale simulation of organic heterojunction light harvesting devices
Authors: Porro Matteo , de Falco Carlo , Verri Maurizio , Lanzani Guglielmo , Sacco Riccardo
Published: July 2014

Purpose

– The purpose of this paper is to develop a computational model for the simulation of heterojunction organic photovoltaic devices with a specific application to a light harvesting capacitor (LHC) consisting of a double layer of organic materials connected in series with two insulating layers and an external resistive load.

Design/methodology/approach

– The model is based on a coupled system of nonlinear partial and ordinary differential equations describing current flow throughout the external resistive load as the result of exciton generation in the bulk, exciton dissociation into bonded pairs at the acceptor-donor material interface, and electron/hole charge generation and drift-diffusion transport in the two device materials.

Findings

– Numerical simulation results are shown to be in good agreement with measured on-off transient currents and allow for novel insight on the microscopical phenomena which affect the external LHC performance, in particular, the widely different time scales at which such phenomena occur and their relation to the overall device dynamics.

Originality/value

– The LHC demonstrates the viability of a novel approach for converting light energy into an electric current without a steady state flow of free charge carriers through the semiconducting layers. The new insight about the microscopic working principles that determine the macroscopically observed behavior of the LHC obtained via the model proposed in this paper are expected to serve as a basis for studying techniques for exploiting the full potential of the LHC.
Optimizing engagement: brand identification and alumni donation behaviors
Authors: L. Stephenson Amber , B. Yerger David
Published: July 2014

Purpose

– As colleges and universities face the shifts of decreasing government funds, increased operating costs, and waning alumni financial support, institutions are now plunging themselves into practices traditionally associated with the business sector. Practices like branding are now being used as a mechanism to increase engagement of alumni and potential donors. The purpose of this paper is to examine the effects of brand identification, or the defining of the self through association with an organization, on alumni supportive behaviors.

Design/methodology/approach

– The researchers surveyed alumni of a mid-sized state-run university in the mid-Atlantic region of the USA to see if identification affected donation behaviors such as choice to donate, total dollar amount donated, and the number of times donated.

Findings

– The survey findings showed that brand identification correlated with choice to donate, increased donation dollar amount, and the number of donations. Findings also suggested that interpretation of brand, prestige, satisfaction with student affairs, and participation were positively associated with identification.

Research limitations/implications

– The results of this study are specific to one institution. This research offers support for the importance and value of brand management in higher education. The study also highlights those determinants of brand identification which suggests the use of integrative fundraising techniques.

Originality/value

– The study highlighted that university brand identification increases the explanatory power for alumni donor behaviors over those variables typically explored in traditional donor models.
Developing strategies for communities of practice
Authors: C.K. Cheng Eric , C.K. Lee John
Published: July 2014

Purpose

– The purpose of this paper is to explore strategies to develop communities of practice (CoP) to improve teaching in a school context.

Design/methodology/approach

– A cross-sectional questionnaire is developed to collect data from participants in a project that aims to cultivate a CoP to improve their small class teaching skills. A total of 125 teachers from 35 primary schools participated in the survey. A structural equation model is used to explore the predictive power of the strategies on all three of the CoP elements.

Findings

– Content strategy is confirmed as the predictor of all the CoP elements, while process strategy is a predictor only for joint enterprise and shared repertoire.

Practical implications

– The application of these strategies to develop a CoP in schools involves designing a reflective and collaborative learning content, as well as monitoring, regulating and streamlining the learning process.

Originality/value

– The study contributes an empirical framework to the research of CoP and practical guides for school leaders to facilitate knowledge sharing in CoPs.
Leading school change in China: a review of related literature and preliminary investigation
Authors: Tang Shaobing , Lu Jiafang , Hallinger Philip
Published: July 2014

Purpose

– Like other nations in Asia, mainland China has undergone continuous reforms in its economic, political and social institutions over the past two decades. These changes are also reflected in its education system, which has been both the target of government reforms and an agent for social change. In this context, China's Ministry of Education has cast school principals as key actors in leading and managing change in schools at the local level throughout the country. The purpose of this paper is to explore how Chinese school leaders successfully respond to the implementation of educational reform.

Design/methodology/approach

– In this paper the authors explore how school leaders in one city in South China perceive their roles and actions in fostering successful change. The study employed extensive literature review with qualitative interviews of five school principals who had demonstrated success at leading change in their schools.

Findings

– The findings of both the literature review and interview study unexpectedly found more similarities than differences between how leaders contribute to successful change in China as compared with the Western literature.

Research limitations/implications

– The research findings are limited by two main features. First, the sources analyzed in the literature review were of highly varying quality. Moreover, relatively few employed replicable analytical methods capable of generalization. These limitations of the literature mean that the results of the review can only be interpreted as suggestive rather than conclusive. Second, the interview study was framed as an effort to further explore the trends of the literature review. Although the findings from the small-scale interview study were consistent with the broader Chinese literature, the research design suffers form the same limitations as the general literature. Therefore, these findings must also be treated as emergent rather than explanatory.

Practical implications

– The paper identifies directions for future research and discusses implications for school leaders in implementing educational change in China.

Originality/value

– The originality of this study lies in its attempt to synthesize a previously inaccessible literature on change leadership in Chinese schools. Despite China's rising role as a global leader, the literature in educational leadership and management remains sparse and largely unknown to Western scholars. Therefore, the study's limitations are balanced by the need to provide better descriptions of current practices employed by leaders as they attempt to improve China's schools.
The impact of collaborative engagement on knowledge and performance gains in episodic collaborations
Authors: W. Nix Nancy , G. Zacharia Zach
Published: July 2014

Purpose

– Supply chains are embedded in a larger network of enterprises where firms exchange offerings, often compete for the same customers, and constantly innovate to improve their performance. In these dynamic environments, firms are increasingly dependent on the knowledge and expertise in external organizations to innovate, problem-solve, and improve performance. Firms are increasingly collaborating to exchange and pool skills and knowledge and deploy resources and capabilities not found in their own firm. This research using both structured interviews and survey data seeks to determine what are the direct benefits and the ancillary benefits of collaboration. The paper aims to discuss these issues.

Design/methodology/approach

– A mixed methodology approach was utilized, using qualitative structured interviews leading to developing a research model and then an empirical survey of 473 participants who are involved in their respective organization's collaboration projects. The data were analyzed using structural equation modeling to examine relationships between collaborative engagement, knowledge gained, operational outcomes and relational outcomes.

Findings

– The results of the study indicate that collaborative engagement has a direct effect on knowledge gained, operational outcomes and relational outcomes in collaboration. The ancillary benefit of collaboration is the learning that takes place leads to improved operational outcomes and relational outcomes.

Research limitations/implications

– In this research study all the constructs are only examined from a single perspective. This can be a limitation as it would be of greater value to collect data from all the members involved in the collaboration.

Originality/value

– Collaboration has been well studied in many fields but this research suggests an important ancillary benefit that needs to be considered when deciding to collaborate is the knowledge and learning that happens during a collaboration.
A reverse logistics inventory model for plastic bottles
Authors: Matar Nouri , Y. Jaber Mohamad , Searcy Cory
Published: July 2014

Purpose

– The purpose of this paper is to present an original model for the production-recycling-reuse of plastic beverage bottles.

Design/methodology/approach

– It is assumed that discarded two-liter plastic polyethylene terephthalate (PET) bottles are collected from the market. The bottles are then sorted into non-contaminated and contaminated streams. The non-contaminated PET bottles are either remanufactured or used as regrind mixed with virgin PET to produce new bottles to satisfy varying demand. The contaminated bottles are either sold to industries using low-grade plastic or disposed of in a landfill. Numerical studies are used to illustrate the behaviour of the model, with an emphasis on exploring the reduction of total system cost and the amount of bottles going into a landfill.

Findings

– Numerical analyses conducted on the model found that the amount of bottles collected had the largest influence on the outcome of the total system unit time cost. Alternative materials to PET are surveyed and used to demonstrate a significant reduction in the cost of landfill disposal due to their more rapid degradation in the landfill.

Research limitations/implications

– Several areas for future work are highlighted. Potential modifications to the model could focus on accommodating bottles made of material other than plastic, incorporating the effects of learning on manual tasks, and on accommodating shortages or excess inventory.

Originality/value

– The model incorporates several unique aspects, including accounting for the cost of land use and associated environmental damage through the calculation of a present value that is charged to the manufacturer.
Correlates of customer loyalty to financial institutions: a case study
Authors: Yavas Ugur , Babakus Emin , D. Deitz George , Jha Subhash
Published: July 2014

Purpose

– The purpose of this study is to investigate the relative efficacies of intrinsic and extrinsic cues as drivers of customer loyalty to financial institutions between male and female bank customers.

Design/methodology/approach

– A large-scale survey of 872 customers of a national bank serves as the study setting.

Findings

– Results showed that extrinsic cues were the more effective correlates of customer loyalty and that gender does not moderate the relationships between image cues and customer loyalty.

Research limitations/implications

– The cross-sectional nature of the current study does not allow causal inferences. Therefore, future studies should adopt longitudinal designs.

Practical implications

– Results suggest that, although transmitting a favorable image through extrinsic cues is critical, nevertheless, intrinsic cues (interactions among customers and bank personnel) should not be ignored. To reinforce this not only among current customers but also among potential customers, banks should use advertisements featuring favorable testimonials.

Originality/value

– Empirical research in the banking services literature pertaining to the efficacies of intrinsic and extrinsic cues in forming customer loyalty is scarce. This study fills in the void. Also, in determining if the relationships between image and customer loyalty vary by gender, the authors not only looked at male versus female differences on the basis of average construct scores but also examined the structural relationships among the constructs.
Functional assessment of mycosporine‐like amino acids in Microcystis aeruginosa strain PCC 7806
Authors: Hu Chenlin , Völler Ginka , Süßmuth Roderich , Dittmann Elke , Kehr Jan‐Christoph
Published: July 2014

The biological role of the widespread mycosporine‐like amino acids (MAAs) in cyanobacteria is under debate. Here, we have constructed and characterized two mutants impaired in MAA biosynthesis in the bloom‐forming cyanobacterium Microcystis aeruginosa PCC 7806. We could identify shinorine as the sole MAA type of the strain, which is exclusively located in the extracellular matrix. Bioinformatic studies as wells as polymerase chain reaction screening revealed that the ability to produce MAAs is sporadically distributed within the genus. Growth experiments and reactive oxygen species quantification with wild‐type and mutant strains did not support a role of shinorine in protection against UV or other stress conditions in M. aeruginosa PCC 7806. The shinorine content per dry weight of cells as well as transcription of the mys gene cluster was not significantly elevated in response to UV‐A, UV‐B or any other stress condition tested. Remarkably, both mutants exhibited pronounced morphological changes compared with the wild type. We observed an increased accumulation and an enhanced hydrophobicity of the extracellular matrix. Our study suggests that MAAs in Microcystis play a negligible role in protection against UV radiation but might be a strain‐specific trait involved in extracellular matrix formation and cell–cell interaction.