bluuebunny/crossref_metadata_2025 huggingface dataset:
Primary prevention of latex allergy in healthcare—spectrum of strategies including the European glove standardization
Authors: Wrangsjö Karin , Boman Anders , Lidén Carola , Meding Birgitta
Published: March 2012

IgE‐mediated allergy to natural rubber latex was first noted from rubber gloves in 1979. The initial reports in dermatological journals described contact urticarial reactions; later, severe generalized allergic reactions and asthma were documented. A considerable proportion of the people involved in medical and dental care were found to be sensitized to latex. This article describes and surveys a broad range of primary prevention measures at the local and national levels. Examples are given from paediatrics, dental education, and medical care. National strategies and position papers on latex allergy are presented in which medical professionals, manufacturers and public authorities have cooperated. Special reference is paid to the European work to standardize medical gloves, which led to document EN 455:3.
Escape from the Red Queen: an overlooked scenario in coevolutionary studies
Authors: Leung Tommy L. F. , King Kayla C. , Wolinska Justyna
Published: March 2012

Almost all eukaryotic organisms undergo sexual recombination at some stage of their life history. However, strictly asexual organisms should have higher per capita rate of reproduction compared with those that have sex, so the latter must convey some advantage which overrides the reproductive benefit of asexuality. For example, sexual reproduction and recombination may play an important role in allowing organisms to evolutionarily ‘keep up’ with parasites. Host–parasite coevolution can operate via negative frequency‐dependent selection whereby parasite genotypes adapt to infect host genotypes as they become locally common. By producing more genetically diverse offspring with unique genotypes, sexual organisms have an advantage over asexual counterparts. Essentially, sexual hosts are more difficult for coevolving parasites to ‘track’ over time. This scenario has been named the “Red Queen hypothesis”. It refers to a passage in Lewis Carroll's ‘Through the Looking Glass’ in which the Red Queen tells Alice: ‘it takes all the running you can do, to keep in the same place’; this statement resembles the negative frequency‐dependent dynamics of host–parasite coevolution.
Temporal stability of European rocky shore assemblages: variation across a latitudinal gradient and the role of habitat‐formers
Authors: Bulleri F. , Benedetti‐Cecchi L. , Cusson M. , Maggi E. , Arenas F. , Aspden R. , Bertocci I. , Crowe T. P. , Davoult D. , Eriksson B. K. , Fraschetti S. , Golléty C. , Griffin J. N. , Jenkins S. R. , Kotta J. , Kraufvelin P. , Molis M. , Pinto I. Sousa , Terlizzi A. , Valdivia N. , Paterson D. M.
Published: March 2012

Compensatory dynamics, overyielding and statistical averaging are mechanisms promoting the temporal stability of natural communities. Using the model of European intertidal rocky shore assemblages and collating 17 datasets, we investigated how the strength of these stability‐enhancing mechanisms varies with latitude and how it can be altered by the loss of habitat‐formers (e.g. canopy‐forming macroalgae). Community stability decreased with increasing latitude, mostly as a consequence of a greater synchronization of species fluctuations. Statistical averaging and overyielding (i.e. richness effect) promoted stability, but their strength did not vary with latitude. An experimental removal of macroalgal canopies caused a strengthening of the statistical averaging effect that was consistent across the latitudinal gradient investigated. Nonetheless, the loss of canopies depressed stability by enhancing the synchronization of species fluctuations on southernmost shores, while it had weak effects on shores at higher latitudes. Variation in life‐history traits among canopy‐forming species and/or in prevailing environmental conditions across a gradient of latitude could underlie variable effects of habitat‐formers on species fluctuations. Our study shows 1) that the stability of intertidal assemblages and strength of compensatory dynamics varies with latitude, 2) that canopy‐forming macroalgae, exerting a strong control on understorey species, can influence the strength of compensatory dynamics and 3) that biological forcing (i.e. facilitation) can be as important as environmental forcing in enhancing the synchronization of species fluctuations.
An integrative review of the literature about the transition of pediatric patients with intestinal failure from hospital to home
Authors: Murray John S. , Mahoney Judith M.
Published: March 2012

Purpose.  Children with intestinal failure (IF) have complex needs that pose many challenges while in the hospital and upon transition to home. The purpose of this review was to identify factors associated with the complexity of transitional care in this population of children, as well as to explore frameworks for providing care for transition to home.

Design and Method.  Eleven publications, including research and clinical practice articles, were identified for an integrative review.

Results.  Four themes emerged regarding IF and transition: complex healthcare needs, planning for and beginning transition, identification of family requirements, and frameworks for providing transitional care.

Practice Implications.  Nurses working with families of children with IF can facilitate successful transition into the home by planning in advance and using a framework that addresses the needs of the patient and family.
Best practices for improving intervention fidelity that every nurse should know
Authors: Horner Sharon D.
Published: March 2012

Column Editor: Lauren Clark

Scientific Inquiry provides a forum to facilitate the ongoing process of questioning and evaluating practice, presents informed practice based on available data, and innovates new practices through research and experimental learning.
Knowledge and attitudes of primary care physicians toward the nurse practitioner role in the Kingdom of Bahrain
Authors: Nasaif Husain Ali ,   Doctor of Nursing Practice, Nursing Faculty, Royal College of Surgeons‐Bahrain, Busaiteen, Kingdom of Bahrain
Published: March 2012

Abstract  Purpose: The Kingdom of Bahrain is facing a number of challenges, including an escalating cost of health services, increasing incidence of chronic diseases, and shortage of primary care physicians (PCPs). Introducing the nurse practitioner (NP) specialty in the primary care setting is one way to meet these challenges. The purpose of this quasi‐experimental study was to examine the knowledge and attitudes of PCPs about the NP role prior to and following an educational intervention.

Data sources: The modified Northern Emergency Nurse Practitioner Staff Survey was used to measure the PCPs’ attitudes and knowledge. A total of 90 PCPs completed the pretest and posttest.

Conclusions: The study findings showed that PCPs had poor understanding of the NP role. Their knowledge and attitudes changed significantly after the educational intervention. Also, posttest data indicated a positive correlation between knowledge and attitudes toward the NP role.

Implications for practice: More educational preparation and orientation to the NP role for PCPs and other healthcare professionals are needed before the implementation of the role in the primary care setting in Bahrain. There is a need for the role to be clearly defined prior to implementation to help gain understanding and acceptance.
Neuroprotection for Ischaemic Stroke: Translation from the Bench to the Bedside
Authors: Sutherland Brad A. , Minnerup Jens , Balami Joyce S. , Arba Francesco , Buchan Alastair M. , Kleinschnitz Christoph
Published: March 2012

Neuroprotection seeks to restrict injury to the brain parenchyma following an ischaemic insult by preventing salvageable neurons from dying. The concept of neuroprotection has shown promise in experimental studies, but has failed to translate into clinical success. Many reasons exist for this including the heterogeneity of human stroke and the lack of methodological agreement between preclinical and clinical studies. Even with the proposed Stroke Therapy Academic Industry Roundtable criteria for preclinical development of neuroprotective agents for stroke, we have still seen limited success in the clinic, an example being NXY-059, which fulfilled nearly all the Stroke Therapy Academic Industry Roundtable criteria. There are currently a number of ongoing trials for neuroprotective strategies including hypothermia and albumin, but the outcome of these approaches remains to be seen. Combination therapies with thrombolysis also need to be fully investigated, as restoration of oxygen and glucose will always be the best therapy to protect against cell death from stroke. There are also a number of promising neuroprotectants in preclinical development including haematopoietic growth factors, and inhibitors of the nicotinamide adenine dinucleotide phosphate oxidases, a source of free radical production which is a key step in the pathophysiology of acute ischaemic stroke. For these neuroprotectants to succeed, essential quality standards need to be adhered to; however, these must remain realistic as the evidence that standardization of procedures improves translational success remains absent for stroke.
Experiments on an integrated aquaculture system (seaweeds and marine fish) on the Red Sea coast of Saudi Arabia: efficiency comparison of two local seaweed species for nutrient biofiltration and production
Authors: Al‐Hafedh Yousef S. , Alam Aftab , Buschmann Alejandro H. , Fitzsimmons Kevin M.
Published: March 2012

Seaweeds absorb inorganic nutrient wastes from mariculture and reduce their undesirable environmental effects. Mariculture in Saudi Arabia is increasing rapidly, thus, to exploit aquaculture wastes and to reduce coastal pollution risks, local seaweeds were cultured using mariculture effluents in integration on the Red Sea coast. The aim of the present study was to test integrated aquaculture of seaweed and marine fish (Oreochromis spilurus) for the first time in Saudi Arabia and to determine the seaweeds, Ulva lactuca and Gracilaria arcuata, biomass production and inorganic nutrient bioremediation capabilities. Results showed that G. arcuata grew at a significantly higher rate (2.71% wet weight day−1) than U. lactuca (1.77% wet weight day−1). The biomass yield (42.38 g wet weight m−2 day−1) and net yield (91.11 g wet weight day−1) of G. arcuata were also significantly higher than U. lactuca (27.39 g wet weight m−2 day−1 and 58.89 g wet weight day−1, respectively). Gracilaria arcuata removed 0.45 g m−2 day−1 of total ammonia nitrogen (TAN) with 80.15% removal efficiency and 1.03 g m−2 day−1 of soluble phosphate with 41.06% efficiency. Ulva lactuca removed 0.42 g m−2 day−1 of TAN with 83.06% removal efficiency and 1.07 g m−2 day−1 of soluble phosphate with 41.11% efficiency. Total tissue carbon of both species reached 25.1–26.9% and nitrogen content reached 3.0–3.2% of dry weight. The C/N ratio for both seaweeds was <10, indicating that nitrogen was not a limiting factor in culture. Both seaweeds are suitable for integrated aquaculture and bioremediation, but G. arcuata has relatively higher growth potential.
Two malignant peripheral nerve lesions of non‐neurogenic origin
Authors: Green Ruth A R , O'Donnell Paul , Briggs Timothy W R , Tirabosco Roberto
Published: March 2012

The imaging features and histology of two cases of non‐neurogenic intraneural malignancy – an epithelioid sarcoma and myeloma – are described. These cases are important reminders that not all nerve tumours are of neural origin and also show the crucial importance of a robust multidisciplinary approach to achieve the correct diagnosis and management.
Microbial interactions during residual oil and n‐fatty acid metabolism by a methanogenic consortium
Authors: Morris Brandon E. L. , Herbst Florian‐Alexander , Bastida Felipe , Seifert Jana , von Bergen Martin , Richnow Hans‐Hermann , Suflita Joseph M.
Published: March 2012

Carbon flow in a model methanogenic consortium capable of hydrocarbon degradation was investigated using a combination of stable isotope fractionation, protein‐based stable isotope probing, and metaproteomics. Overall δ13C enrichment for methane and CO2 in the presence and absence of oil suggests that complex microbial interactions occur during methanogenic hydrocarbon mineralization. Specifically, the Δδ13C of CO2 was statistically identical in all incubations irrespective of oil presence, but the Δδ13C for methane was greater in the presence of oil compared with fatty acids alone. In addition, carbon from uniformly (13C) labelled n‐fatty acids was distributed evenly among consortium members in the presence of oil, but used by relatively few community members when provided alone. In all incubations, aceticlastic and hydrogenotrophic methanogens were labelled to an equal extent, suggesting that no pathway is overwhelmingly dominant during methane production by the model consortium. Protein‐based stable isotope probing identified key enzymes responsible for methanogenesis from CO2 and acetate labelled with 78.0 ± 4.4% and 73.3 ± 1.0% 13C respectively. Results suggest that acetate was used directly by methanogens in the presence of n‐fatty acids alone, and that methanogenesis from CO2 was a secondary process. Proteins capable of catalysing hydrocarbon activation by addition to fumarate were not found. Collectively, this study demonstrates that significant microbial cooperation is required to recover hydrocarbons as methane.
Characterization of carbon nanotube film-silicon Schottky barrier photodetectors
Authors: An Yanbin , Rao Hemant , Bosman Gijs , Ural Ant
Published: March 2012

The authors fabricate vertical geometry single-walled carbon nanotube (CNT) film/p-type silicon Schottky barrier photodetectors, where the CNT film acts as the transparent metal and silicon as the active semiconductor. The authors experimentally characterize the current-voltage, spectral responsivity, and noise properties of these devices under reverse bias. The authors find that the CNT film–Si Schottky barrier photodetectors exhibit a large photocurrent-to-dark current ratio with responsivity as high as 0.10 A/W due to the high transmittance of the CNT film. The measured current noise spectral density shows a 1/f limited behavior and scales as the square of the reverse bias current. The noise equivalent power of the devices is found to be 1.4 × 10−10 W. A comparison between CNT film devices and devices based on conventional metal electrodes is also carried out. These results provide important insights into the properties and performance of CNT film–Si Schottky barrier photodetectors.
GaN surface electron field emission efficiency enhancement by low-energy photon illumination
Authors: Evtukh Anatoli , Yilmazoglu Oktay , Litovchenko Vladimir , Ievtukh Valery , Hartnagel Hans L. , Pavlidis Dimitris
Published: March 2012

The enhancement of electron field emission efficiency due to illumination by low energy photons has been investigated. Illumination of electron field emitting GaN cathodes with light energy lower than the bandgap caused an increase of the emission current and a change in the slope of the emission curves as evidenced by Fowler–Nordheim characteristics. The observed properties suggest a change of effective emission barrier due to charge carrier excitation. The influence of light modulation on the field emission current was also investigated with an increase of emission current only observed at lower light modulation frequencies. Two slopes were observed in the Fowler–Nordheim curves without illumination; namely, a larger slope at lower voltages and a smaller slope at higher voltages. Such behavior has been explained by emission from the Γ- and X-valley, respectively. Key field-emission parameters were determined from the Fowler–Nordheim plots and are reported. Another important peculiarity is the relative decrease of the ratio of illuminated to dark current under maximum voltage operation conditions.
Chimerism and Tolerance Without GVHD or Engraftment Syndrome in HLA-Mismatched Combined Kidney and Hematopoietic Stem Cell Transplantation
Authors: Leventhal Joseph , Abecassis Michael , Miller Joshua , Gallon Lorenzo , Ravindra Kadiyala , Tollerud David J. , King Bradley , Elliott Mary Jane , Herzig Geoffrey , Herzig Roger , Ildstad Suzanne T.
Published: March 2012

Durable chimerism and donor-specific tolerance can be safely achieved without GVHD in HLA-mismatched donor/recipient pairs.
Impersonalized Medicine
Authors: Scrable Heidi
Published: March 2012

Fasting simultaneously enhances normal cell function and potentiates the effects of conventional chemotherapeutic agents on tumor growth, metastasis, and long-term survival.
Relationship between renal dysfunction and outcomes in emergency department patients with potential acute coronary syndromes
Authors: Chang Anna Marie , Edwards Meredith , Matsuura Asako C , Walsh Kristy M , Barrows Emily , Le Jeffrey , Hollander Judd E
Published: March 2012

Objectives

To determine whether patients with elevated creatinine who present to the emergency department (ED) with potential acute coronary syndrome (ACS) are at an increased risk of acute myocardial infarction (AMI) or 30-day cardiovascular (CV) events.

Methods

A secondary analysis of a cohort study of patients presenting to the ED with potential ACS with serum creatinine measurements. Research assistants collected demographics, history, symptoms, hospital course and 30-day follow-up. Outcomes measured were in-hospital AMI and 30-day CV events (death, nonfatal AMI, revascularisation). Prespecified multivariable models included age, gender, race and cardiac risk factors and presenting electrocardiogram (ECG). We used a creatinine cut-off point of 132.6 mmol/l. Data are presented as OR and 95% CI.

Results

3451 patients were enrolled (age, 52.9±13.2; 55% female patients; 64% black patients). There were 120 AMI during initial visit and 232 patients had 30-day CV events (43 deaths, 128 AMI, 120 revascularisations). Creatinine values were normal in 3086 (89.4%) and abnormal in 365 (10.5%) patients. In multivariable models the adjusted OR (95% CI) for the association between abnormal creatinine and AMI was 1.43 (0.88 to 2.30) and 30-day CV events was 1.57 (1.10 to 2.25). The odds of 30-day CV events were increased for patients who were older, male subjects, white, had hyperlipidaemia, hypertension or a history of CAD, or presented with an abnormal ECG.

Conclusion

In patients with potential ACS in the ED, renal dysfunction predicts a higher likelihood of 30-day CV events, but not an independent predictor after controlling for other risk factors. It appears to be a marker of other CV risks.
Impact of the introduction of emergency ultrasound to one large UK emergency department: the REBUS study
Authors: Kwok T'ng Choong , Johnson Sue , Reed Matthew James
Published: March 2012

Aim

Firstly, to detail the experiences of one UK training region in establishing an emergency ultrasound (EU) training programme and secondly, to report the initial 30 months of EU scanning experience.

Methods

Prospective study of all documented emergency department (ED) ultrasound scans. Results were extracted from written paper reports and/or electronically saved images. Details of scan date, time, type of scan, grade of operator, supervision status (whether supervised by a level 1 competent scanner) and whether the scan was clinical (performed or supervised by a level 1 operator) or training, were recorded. EU scans were reviewed for quality (internal quality assurance) and for diagnostic accuracy (external quality assurance).

Results

Between 14 January 2009 and 4 July 2011, 626 scans were performed by 41 operators. 263 (42%) scans were completed outside of normal working hours (09:00 to 17:00). There were 251 abdominal aorta and inferior vena cava scans (40% of all scans) and 198 focused assessment with sonography in trauma scans (32%). The number of scans performed by each operator varied widely. 87 scans (14%) were supervised but the majority (459; 73%) were not. 484 (77%) scans were for training purposes, 124 (20%) were clinical scans and the majority (401; 63%) were performed by either speciality registrars (ST4-6) or specialist registrars (SpR). When the three commonest types of scans performed were analysed, eight false positives and 11 false negatives were identified. Only seven of these were deemed of poor quality and none led to poor patient outcome.

Conclusions

Since the acquisition of our ED ultrasound machine and the development of a quality assured training programme, on average 20 scans per month have been performed in the ED, with no known adverse patient outcomes.
Expression of claudins 7 and 18 in pancreatic ductal adenocarcinoma: association with features of differentiation
Authors: Soini Y , Takasawa A , Eskelinen M , Juvonen P , Kärjä V , Hasegawa T , Murata M , Tanaka S , Kojima T , Sawada N
Published: March 2012

Aim

This study was undertaken to evaluate the expression of claudins 7 and 18 in pancreatic ductal adenocarcinoma.

Methods and results

Material tested included 111 operated samples and 47 additional biopsy samples consisting of 26 cases of pancreatitis, 3 cases of pancreatic intraepithelial neoplasia and 18 ductal adenocarcinomas. Samples were stained with antibodies to claudins 7 and 18 and analysed for membranous and cytoplasmic expression. Membrane bound claudin 7 and 18 expression was detected in 62 of 105 (59%) and 78 of 111 (70%) cases, respectively. Membrane bound claudin 7 and 18 were associated with large or intermediate neoplastic ducts (p=0.01, p=0.002, respectively). Well differentiated pancreatic adenocarcinomas displayed more cases with membrane bound claudin 7 or 18 immunopositivity (p=0.003, p=0.03, respectively). All pancreatic intraepithelial neoplasias studied expressed membrane bound claudin 18. Membrane bound claudin 7 or 18 positivity was not associated with survival (p=0.17, p=0.98). In the biopsy cases membrane bound claudin 18 had 100% specificity and 51% sensitivity for a tumour marker.

Conclusion

Claudin 7 and 18 expression is related to gland size of neoplastic cells and is especially found in tumours with intermediate and large ducts and well differentiated tumours. Membrane bound claudin 18, when present, is a useful marker for diagnosis of pancreatic cancer. Claudins 7 and 18 were not associated with patient survival or spread of tumours.
The embodiment of lyricism in medicine and Homer
Authors: Bleakley Alan , Marshall Robert J
Published: March 2012

Improving the quality of communication between doctors and their patients and colleagues is of vital importance. Poor communication, especially within and across clinical teams working around patients in pathways of care, leads to avoidable medical error, where an unacceptable number of patients are severely harmed or die each year. The figures from such iatrogenesis have now reached epidemic proportions, constituting one of the major killers of patients worldwide. Despite 30 years' worth of explicit attention to teaching communication skills at undergraduate level, communication in medicine is failing to improve at an acceptable rate. The authors suggest a rather unusual approach to this dilemma of ‘communication hypocompetence’—thinking medicine lyrically—as an extension of thinking with Homer's little-discussed lyrical aesthetic. A key part of the problem of communication hypocompetence is the well-researched phenomenon of ‘empathy decline’ in students, where ‘hardening’ and cynicism occur as over-determined ego defences. Empathy decline may be a symptom of the repression of the lyrical genre in medicine, where the epic, tragic and dark comic genres dominate. The lyrical genre emphasises coming to know the patient as a person and an individual. Importantly, central to performing the lyric genre is the heightened use of the senses in taking a history, physical examination and diagnostic work. Framing medicine as lyrical work challenges undue emphasis on ‘cure’ at the expense of humane ‘care’.
Acquiring DNA sequence data from dried archival red algae (Florideophyceae) for the purpose of applying available names to contemporary genetic species: a critical assessment
Authors: Saunders Gary W. , McDevit Daniel C.
Published: March 2012

Two DNA extraction protocols and nine variations of advocated DNA barcode markers (nuclear LSU D2/D3, ITS1, ITS2, mitochondrial COI-5P, plastid rbcL, UPA) were assessed for their abilities to yield species-level resolution from archival collections of red algae. With the exception of LSU D2/D3, all markers trialed displayed the potential to resolve red algal species. However, shortened COI-5P (COIms) and ITS (ITS2r) markers displayed four to five times the intrageneric divergence of shortened plastid markers and are preferred for their resolving power. For recent archival samples (4–11 years), COIms, ITS2r, and UPA displayed >90% amplification success. However, success rates declined rapidly as samples ranging in age from ca. 45–180 years old were tested. Further, contamination was a serious concern in reamplifications (partially nested PCR), especially for markers using universal primers (e.g., UPA) and for trials that employed the best extraction procedure, i.e., the better an extraction protocol is at isolating small DNA fragments from archival material, the better it is at acquiring small contaminating fragments from the laboratory — an intuitive and unfortunate reality. The ramifications of our results for ongoing attempts to extract DNA from archival red algal collections using PCR-based protocols is discussed along with recommendations to improve the likelihood of authentic outcomes.
Genetic differentiation within the Paralia longispina (Bacillariophyta) species complex
Authors: MacGillivary Michael L. , Kaczmarska Irena
Published: March 2012

We report on undiscovered genetic and morphological diversity within a diatom taxon known as Paralia longispina and propose three new, extant species of Paralia — Paralia allisonii sp. nov., Paralia crawfordii sp. nov., and Paralia ehrmanii sp. nov. — obtained from subtropical and tropical coasts of the Atlantic and Pacific oceans. Comprehensive examination and hierarchical clustering of frustule characters separated these three species from each other and from P. longispina. Each species possessed one or two unique morphological diagnostic characters. The internal transcribed spacer (ITS) region and a fragment of the small subunit (18S rRNA gene) of nuclear encoded rRNA and a portion of the 5′ end of the large subunit of the ribulose bisophosphate carboxylase (rbcL) gene of the chloroplast genome were related to the morphological groupings of monoclonal isolates of P. allisonii and P. crawfordii. The ITS2 secondary structure of the cultured clones of these two species had four helices. They differed by five hemicompensatory base changes (HCBCs) and substantial changes to the distal end of helix I, the region between helix II and helix III, and nearly all of helix IV. Our results better our understanding of the distribution of subtropical and tropical species of Paralia and have practical implications for the conservation of native microbial florae and for the possibility of ship ballast in human-mediated dispersal of these diatoms.
Within-species leaf size–number trade-offs in herbaceous angiosperms
Authors: Scott Stephanie L. , Aarssen Lonnie W.
Published: March 2012

Leafing intensity—number of leaves produced per unit of supporting (nonleaf, aboveground) dry mass—determines the size of a plant’s “bud bank”, i.e., the number of axillary meristems per unit plant body or shoot size. This in turn determines the plant’s capacity for flexible and economic meristem deployment strategies as vegetative or reproductive structures. From recent research, it is now widely established that leafing intensity has a strong and isometrically negative relationship with individual leaf mass at the between-species level for both woody and herbaceous species. In the present study of 24 natural populations of herbaceous angiosperms, we show that these two traits also have a general trade-off relationship at the between-plant level within a species. Smaller resident reproductive (i.e., mature) plants generally produced smaller leaves, and plants with smaller leaves generally had higher leafing intensity, in most cases involving an isometric trade-off. For several species, however, the trade-off was allometric—i.e., plants with smaller leaves, which also had generally smaller body sizes, had generally greater than proportionally higher leafing intensity. This parallels results of an earlier study at the between-species level suggesting that, when plant body size is relatively small, there may be a premium—in terms of maximizing fitness—on relatively high leafing intensity. The latter, it is proposed, may function in maximizing the capacity for “reproductive economy”, i.e., successful reproduction despite intense size suppression owing to competition.
Microwave propagation in a magnetized inhomogeneous plasma slab using the Appleton–Hartree magnetoionic theory
Authors: Bawa’aneh M.S. , Al-Khateeb A.M. , Sawalha A.S.
Published: March 2012

Electromagnetic wave propagation in a nonuniform, collisional, magnetized plasma slab is investigated within magnetoionic theory. We allow for the presence of an ideal conductor at a distance d from the right transmissive plasma boundary, and derive the reflection, absorption, and transmission coefficients analytically for an arbitrary inhomogeneous plasma density profile. Dividing the inhomogeneous plasma slab into n thin layers allows for treating each layer as a homogeneous plasma and, therefore, the complex index of refraction of the magnetoionic theory is used to express the complex propagation vector of the waves in each layer. Upon matching the fields at all interfaces, a global matrix is formed that allows for the determination of the reflection, absorption, and transmission coefficients analytically. Results show that in the absence of the metallic wall, the reflected signal is a weak peak near ωce, while in the presence of the metallic wall this weak signal is overwhelmed by a strong transmitted peak from right to left after it has been reflected by the perfectly conducting metallic wall. Also, formation of a wider stealth band as the plasma density increases is observed.
Covariant gauge fixing and canonical quantization
Authors: McKeon D.G.C.
Published: March 2012

Theories that contain first-class constraints possess gauge invariance, which results in the necessity of altering the measure in the associated quantum mechanical path integral. If the path integral is derived from the canonical structure of the theory, then the choice of gauge conditions used in constructing Faddeev’s measure cannot be covariant. This shortcoming is normally overcome either by using the “Faddeev–Popov” quantization procedure, or by the approach of Batalin–Fradkin– Fradkina–Vilkovisky, and then demonstrating that these approaches are equivalent to the path integral constructed from the canonical approach with Faddeev’s measure. We propose, in this paper, an alternate way of defining the measure for the path integral when it is constructed using the canonical procedure for theories containing first-class constraints, and that this new approach can be used in conjunction with covariant gauges. This procedure follows the Faddeev–Popov approach, but rather than working with the form of the gauge transformation in configuration space, it employs the generator of the gauge transformation in phase space. We demonstrate this approach to the path integral by applying it to Yang–Mills theory, a spin-two field and the first-order Einstein–Hilbert action in two dimensions. The problems associated with defining the measure for theories containing second-class constraints and ones in which there are fewer secondary first-class constraints than primary first-class constraints are discussed.
Three region model and quantum enhancement of thermionic and photoelectric electron emission from negatively charged metallic surfaces
Authors: Agarwal Sujeet , Misra Shikha , Mishra S.K. , Sodha M.S.
Published: March 2012

In this paper the authors have evaluated the transmission coefficient of electrons across a negatively charged plane metallic surface on the basis of a three region model for variation of the potential energy of an electron near the surface, which incorporates a field free region, in contrast to usual two region model. It is seen that the old two region model significantly overestimates the transmission coefficient and consequently electron emission current. An additional mechanism (other than Schottky and electric field emission) for enhancement of electron emission by a negative charge on the plane surface of the metal has also been analyzed.
Modulational instability of high frequency surface waves on warm plasma half-space
Authors: Ghosh Basudev , Paul Sailendra Nath , Das Chandra , Paul Indrani
Published: March 2012

Modulational instability of high frequency surface waves on a plasma half-space is investigated taking into account finite temperature effects. The second harmonic generated through nonlinear self-interaction of the waves is found to carry a fraction of the surface wave energy into the bulk of the plasma. This is found to influence the modulational instability mechanism. To describe the nonlinear evolution of the wave, a nonlinear Schrödinger equation is derived in which the coefficient of the nonlinear term becomes a complex quantity. From this evolution equation we derive the condition of instability and show that high-frequency surface waves on a warm plasma half-space are modulationally unstable.
CONTINUOUS X-RAY PRODUCTION CROSS-SECTION IN THIN POLYMER FILMS
Authors: BALOURIA P. , GOVIL I. M. , MOHANTY B. P. , GARG M. L. , ISHII K.
Published: March 2012

We have calculated the production cross-sections of continuous X-rays for commonly used thin polymer films on the basis of the theories of quasi-free electron bremsstrahlung (QFEB), secondary electron bremsstrahlung (SEB), atomic bremsstrahlung (AB) and nuclear bremsstrahlung (NB). These results are compared with that of experimental one. We found that SEB is the main contributing factor and the contribution of QFEB, AB and NB is negligible. This work would facilitate choice among available polymer materials and lay down well-defined standard data against which new candidates might be judged.
DEVELOPMENT OF μ-PIXE/RBS/SEM SYSTEM FOR CORROSION LAYER ANALYSIS OF STEEL
Authors: MATSUYAMA S. , ISHII K. , FUJIWARA M. , KIKUCHI Y. , SUGAI H. , FUJIKI K. , HATORI Y. , HAMADA N. , ITO Y. , HIRAISHI S. , MIURA Y. , FUKAYA A. , TANNO S. , ABE H. , WATANABE Y. , YAMAZAKI H.
Published: March 2012

Wall thinning of piping made of carbon steel when exposed to high temperature water flow and va-por is a common problem in all types of these plants. Oxide layer formation and dissolution should be related to the mechanism of corrosion. In order to understand the mechanism of corrosion, characterization of oxide layer including elemental concentration in the localized area is indispensable. In this study, simultaneous μ-PIXE/RBS/SEM analysis system was developed to obtain elemental characterization on oxide layer in localized area as well as to obtaining surface condition. Carbon steel samples were oxidized dynamically for 1100 hours and analyzed by the system. The oxide layer is not uniform even in the localized area of 30 × 30 μm2. In the chromium content of 0.003 wt%, oxide layer thickness varied from 0.71 to 1.2 mg/cm2. While accumulation of chromium is seen in the map, accumulation is not related to the iron distribution. Chromium and iron ratio in the accumulated region is more than five times higher than that of the other area. The higher chromium and iron ratio indicates that chromium migrate from substrate to oxide layer. In the chromium content of 1.01 wt%, oxide layer thickness varies from 1.4 to 3.9 mg/cm2. Oxide layer is thicker than that in the chromium content of 1.01 wt%, which is opposite to the result in the static condition. Large variation of X-ray yield of iron indicates that dissolution of the oxide layer might occur during long exposure to the water flow. These results of this experiment obviously show the simultaneous μ-PIXE/RBS and SEM analysis system to be useful for better understanding of the corrosion mechanism.
INTERFERENCE IN FAR-FIELD RADIATION OF EVANESCENT FIELDS
Authors: CORTES R. , COELLO V. , SEGOVIA P. , GARCÍA C. , MERLO J. M. , AGUILAR J. F.
Published: March 2012

We investigate experimentally the interference in far-field radiation of two contra-propagating evanescent fields using a conventional optical microscope. A laser beam illuminates a glass-air interface under total internal reflection condition and through the proper setup a double evanescent illumination was produced. The evanescent fields radiate from the surface into the far-field domain due to small surface scatterers. Thus, coherent interference is produced in the far-field region which is correlated with the relative positions of the evanescent illumination sources. Finally, the above-described could be considered as a device for high accuracy micro-scale measurements as well as a direct visualization method of evanescent phenomena.
SOLIDIFICATION CHARACTERISTICS AND MICROSTRUCTURAL EVOLUTION OF Zn-1.26wt.% Al ALLOY
Authors: ŞAHİN MEVLÜT , ÇADIRLI EMİN
Published: March 2012

Zn–1.26 wt.% Al alloy was directionally solidified upward with a constant growth rate (V = 16.6 μm/s) in a wide range of temperature gradients (G = 1.94–5.15 K/mm) and with a constant temperature gradient (G = 5.15 K/mm) in a wide range of growth rates (V = 8.3–500 μm/s) with a Bridgman-type directional solidification furnace. Microstructure parameters, the primary dendrite arm spacing (λ1), secondary dendrite arm spacing (λ2) and dendrite tip radius (R), were measured and expressed as functions of G and V by using a linear regression analysis method. It was found that the values of λ1, λ2 and R decrease with increasing values of V and G. The experimental results were compared with the main predictive theoretical and experimental works for dendritic spacings.
Continuous Characterizations of Besov-Lizorkin-Triebel Spaces and New Interpretations as Coorbits
Authors: Ullrich Tino
Published: March 2012

We give characterizations for homogeneous and inhomogeneous Besov-Lizorkin-Triebel spaces (H. Triebel 1983, 1992, and 2006) in terms of continuous local means for the full range of parameters. In particular, we prove characterizations in terms of Lusin functions (tent spaces) and spaces involving the Peetre maximal function to apply the classical coorbit space theory according to Feichtinger and Gröchenig (H. G Feichtinger and K. Gröchenig 1988, 1989, and 1991). This results in atomic decompositions and wavelet bases for homogeneous spaces. In particular we give sufficient conditions for suitable wavelets in terms of moment, decay and smoothness conditions.
A Secure Image Encryption Algorithm Based on Rubik′s Cube Principle
Authors: Loukhaoukha Khaled , Chouinard Jean-Yves , Berdai Abdellah
Published: March 2012

In the past few years, several encryption algorithms based on chaotic systems have been proposed
as means to protect digital images against cryptographic attacks. These encryption algorithms typically
use relatively small key spaces and thus offer limited security, especially if they are one‐dimensional.
In this paper, we proposed a novel image encryption algorithm based on Rubik′s cube principle. The
original image is scrambled using the principle of Rubik′s cube. Then, XOR operator is applied to rows
and columns of the scrambled image using two secret keys. Finally, the experimental results and security
analysis show that the proposed image encryption scheme not only can achieve good encryption and
perfect hiding ability but also can resist exhaustive attack, statistical attack, and differential attack.
The Current Role of Carotid Duplex Ultrasonography in the Management of Carotid Atherosclerosis: Foundations and Advances
Authors: Byrnes Kelly R. , Ross Charles B.
Published: March 2012

The management of atherosclerotic carotid occlusive disease for stroke prevention has entered a time of dramatic change. Improvements in medical management have begun to challenge traditional interventional approaches to asymptomatic carotid stenosis. Simultaneously, carotid artery stenting (CAS) has emerged as an alternative to carotid endarterectomy (CE). Finally, multiple factors beyond degree of stenosis and symptom status now mitigate clinical decision making. These factors include brain perfusion, plaque morphology, and patency of intracranial collaterals (circle of Willis). With all of these changes, it seems prudent to review the role of carotid duplex ultrasonography in the management of atherosclerotic carotid occlusive disease for stroke prevention. Carotid duplex ultrasonography (CDU) for initial and serial imaging of the carotid bifurcation remains an essential component in the management of carotid bifurcation disease. However, correlative axial imaging modalities (computer tomographic angiography (CTA) and contrast-enhanced magnetic resonance angiography (CE-MRA)) increasingly aid in the assessment of individual stroke risk and are important in treatment decisions. The purpose of this paper is twofold: (1) to discuss foundations and advances in CDU and (2) to evaluate the current role of CDU, in light of other imaging modalities, in the clinical management of carotid atherosclerosis.
The Columbus Knee System: 4-Year Results of a New Deep Flexion Design Compared to the NexGen Full Flex Implant
Authors: Goebel D. , Schultz W.
Published: March 2012

The Columbus knee system is designed as a standard knee implant to allow high flexion without additional bone resection. Between August, 2004 and March, 2010 we performed 109 total knee arthroplasties of the Columbus knee system in 101 consecutive patients suffering from primary arthrosis of the knee. Mean age was 72.4 years in women and 70.3 years in men. Mean followup was 47.3 months. The 4-year results of a group of patients who received the NexGen Full Flex implant operated by the same surgeon were used for comparison. Mean total knee score was Columbus: 175.6 and NexGen Flex: 183.4; . Mean operation time was 53 min for Columbus and 66 min for NexGen Flex; . With new streamlined instruments operative time became 60 min for the Columbus; . Radiological assessment showed no signs of loosening for both groups.
Therefore, the Columbus knee system can be recommended for flexion angles up to .
Improved DCT-Based Nonlocal Means Filter for MR Images Denoising
Authors: Hu Jinrong , Pu Yifei , Wu Xi , Zhang Yi , Zhou Jiliu
Published: March 2012

The nonlocal means (NLM) filter has been proven to be an efficient feature-preserved denoising method and can be applied to remove noise in the magnetic resonance (MR) images. To suppress noise more efficiently, we present a novel NLM filter based on the discrete cosine transform (DCT). Instead of computing similarity weights using the gray level information directly, the proposed method calculates similarity weights in the DCT subspace of neighborhood. Due to promising characteristics of DCT, such as low data correlation and high energy compaction, the proposed filter is naturally endowed with more accurate estimation of weights thus enhances denoising effectively. The performance of the proposed filter is evaluated qualitatively and quantitatively together with two other NLM filters, namely, the original NLM filter and the unbiased NLM (UNLM) filter. Experimental results demonstrate that the proposed filter achieves better denoising performance in MRI compared to the others.
Designing a Supply Chain Network under the Risk of Disruptions
Authors: Jabbarzadeh Armin , Jalali Naini Seyed Gholamreza , Davoudpour Hamid , Azad Nader
Published: March 2012

This paper studies a supply chain design problem with the risk of disruptions at facilities. At any point of time, the facilities are subject to various types of disruptions caused by natural disasters, man‐made defections, and equipment breakdowns. We formulate the problem as a mixed‐integer nonlinear program which maximizes the total profit for the whole system. The model simultaneously determines the number and location of facilities, the subset of customers to serve, the assignment of customers to facilities, and the cycle‐order quantities at facilities. In order to obtain near‐optimal solutions with reasonable computational requirements for large problem instances, two solution methods based on Lagrangian relaxation and genetic algorithm are developed. The effectiveness of the proposed solution approaches is shown using numerical experiments. The computational results, in addition, demonstrate that the benefits of considering disruptions in the supply chain design model can be significant.
Effect ofαB-Crystallin on Protein Aggregation inDrosophila
Authors: Tue Nguyen Trong , Shimaji Kouhei , Tanaka Naoki , Yamaguchi Masamitsu
Published: March 2012

Disorganisation and aggregation of proteins containing expanded polyglutamine (polyQ) repeats, or ectopic expression of α-synuclein, underlie neurodegenerative diseases including Alzheimer’s, Parkinson, Huntington, Creutzfeldt diseases. Small heat-shock proteins, such as αB-crystallin, act as chaperones to prevent protein aggregation and play a key role in the prevention of such protein disorganisation diseases. In this study, we have explored the potential for chaperone activity of αB-crystallin to suppress the formation of protein aggregates. We tested the ability of αB-crystallin to suppress the aggregation of a polyQ protein and α-synuclein inDrosophila. We found that αB-crystallin suppresses both the compound eye degeneration induced by polyQ and the α-synuclein-induced rough eye phenotype. Furthermore, by using histochemical staining we have determined that αB-crystallin inhibits the aggregation of polyQin vivo. These data provide a clue for the development of therapeutics for neurodegenerative diseases.
The Concept of Divergent Targeting through the Activation and Inhibition of Receptors as a Novel Chemotherapeutic Strategy: Signaling Responses to Strong DNA-Reactive Combinatorial Mimicries
Authors: Watt Heather L. , Rachid Zakaria , Jean-Claude Bertrand J.
Published: March 2012

Recently, we reported the combination of multitargeted ErbB1 inhibitor–DNA damage combi-molecules with OCT in order to downregulate ErbB1 and activate SSTRs. Absence of translation to cell kill was believed to be partially due to insufficient ErbB1 blockage and DNA damage. In this study, we evaluated cell response to molecules that damage DNA more aggressively and induce stronger attenuation of ErbB1 phosphorylation. We used three cell lines expressing low levels (U87MG) or transfected to overexpress wildtype (U87/EGFR) or a variant (U87/EGFRvIII) of ErbB1. The results showed that Iressa±HN2 and the combi-molecules, ZRBA4 and ZR2003, significantly blocked ErbB1 phosphorylation in U87MG cells. Addition of OCT significantly altered cell cycle distribution. Analysis of the DNA damage response pathway revealed strong upregulation of p53 by HN2 and the combi-molecules. Apoptosis was only induced by a 48 h exposure to HN2. All other treatments resulted in cell necrosis. This is in agreement with Akt-Bad pathway activation and survivin upregulation. Despite strong DNA damaging properties and downregulation of ErbB1 phosphorylation by these molecules, the strongest effect of SSTR activation was on cell cycle distribution. Therefore, any enhanced antiproliferative effects of combining ErbB1 inhibition with SSTR activation must be addressed in the context of cell cycle arrest.