bluuebunny/crossref_metadata_2025 huggingface dataset:
Testing for HIV – the first three decades
Authors: Busch M. P.
Published: April 2015

Background

HIV was discovered in 1984, with high rates of virus isolation and antibody (Ab) detection in haemophiliacs and recipients of blood from HIV‐infected donors, demonstrating the critical need to develop tests for donor screening.

Aims/Methods

Review evolution of HIV‐donor screening, and broader applications of HIV tests and infected‐donor surveillance to research and public health.

Results

In mid‐1984, scientists in governments and industry collaborated to develop HIV‐Ab tests that were implemented in blood banks ~1 year following discovery of HIV. Initial Ab screening did not eliminate TT‐HIV, however, with numerous breakthrough cases detected following introduction of first‐generation assays, which were determined to have an infectious pre‐seroconversion (SC) window period (WP) of ~56 days. Improvements in sensitivity of second‐generation tests in the late‐1980s and third‐generation tests in the mid‐1990s reduced the pre‐SC WP to approximately 3 weeks. Subsequent additions of p24 antigen and then nucleic acid technology (NAT)‐screening in the late 1990s closed the infectious WP to 5–10 days. NAT‐screening assays and algorithms and fourth‐generation Ag/Ab serological tests developed for blood bank screening and staging of early HIV infections are now in widespread use in clinical diagnostic, research and public health settings. NAT assays developed for donor screening have been applied to detect persistent low‐level viral replication in studies of patients on HAART, ‘elite controllers’ and ‘HIV‐eradication’ research.

Conclusions

Progressive improvements in HIV screening assays have virtually eliminated TT‐HIV infections, and consequent advances in HIV testing have contributed to HIV diagnostics, research and public health.
Transfusion‐transmitted Malaria in Sub‐Saharan Africa
Authors: Owusu‐Ofori A. , Owusu‐Ofori S. , Bates I.
Published: April 2015

The World Health Organisation (WHO) recently reported that global efforts to control and eliminate malaria have saved an estimated 3·3 million lives since 2000, reducing malaria mortality rates in Africa alone by 49%. Despite these encouraging statistics, the burden of malaria in Africa remains high. One area of malaria control which has been neglected is malaria transmission through blood transfusion. In sub‐Saharan African (SSA), little is known about the burden of transfusion transmitted malaria (TTM) and how it contributes to the overall burden of malaria. Most studies from SSA report on the prevalence rates of parasitaemia in blood donors, with some rates as high as 50%. Parasitaemia in donors may not necessarily translate to parasitaemia or clinical disease in semi‐immune recipients living in endemic regions of malaria. Using molecular genotyping, two studies in Ghana recently determined the incidence of TTM to be 2% and 28% in adult populations. These incidence rates may not be representative of what occurs across the continent in view of the varied malaria endemicity and transmission intensity in different regions. This review will discuss the peculiarities of TTM in sub‐Saharan Africa with the view to understand the risks and pathophysiology of the disease. The options of preventive strategies for TTM will also be considered.
Handling a transfusion haemolytic reaction
Authors: Yahalom Vered , Zelig Orly
Published: April 2015

Haemolytic transfusion reactions (HTRs) may be immediate/acute (AHTR) usually due to immune ABO incompatibility or delayed (DHTR) seen days to weeks following transfusion and caused by an anamnestic immune response to red cell antigens (Kidd, Rh, Duffy and others). AHTR may cause severe morbidity and mortality even if recognized early. Presently, there is no therapy that can reliably treat the effects of acute haemolysis. Therefore, RBC (and other blood components) should be transfused only if clinically indicated. Strict adherence to guidelines and SOP's is essential for prevention of this avoidable severe complication. Awareness, close observation of patients receiving transfusion, early recognition of a transfusion reaction, prompt cessation of transfusion and appropriate supportive care are essential to minimize morbidity and mortality. Factors influencing the outcome of HTRs include antibody and antigen characteristics as well as patient age and comorbidities. DHTRs are more frequent in patients with sickle cell disease (SCD), thalassaemia and haematological conditions such as autoimmune haemolytic anaemia (AIHA) and myelodysplastic syndromes (MDS). In these patients, distinction between haemolysis caused by alloantibodies or autoantibodies is challenging, especially if hyperhaemolysis is present. Investigation of HTRs should include all aspects of the transfusion chain – administrative, clinical and laboratory. In patients in whom the blood bank laboratory cannot identify a cause for haemolysis, other causes for immune and nonimmune haemolysis should be sought. New insights into the pathogenesis of haemolysis might aid in developing novel therapies for amelioration and treatment of HTRs. Nonetheless, prevention of HTRs should be the major goal.
Non‐invasive prenatal diagnosis – erythrocyte and platelet antigens
Authors: van der Schoot C. E. , Thurik F. F. , Scheffer P. G. , Veldhuisen B. , de Haas M.
Published: April 2015

Non‐invasive fetal blood group typing.
Platelet microparticles in transfusion
Authors: Boudreau L. H. , Marcoux G. , Boilard E.
Published: April 2015

Platelets are active participants in maintaining haemostasis. Upon activation, platelet shed vesicles from their cytoplasmic membrane known as platelet microparticles. These platelet microparticles and their unique cargo are thought to participate in intercellular communication. Platelet transfusion is frequently required for patients with low platelet counts or platelet disorders to restore normal functions. Unfortunately, adverse transfusion reactions are most commonly associated with platelet transfusion than any other type of labile blood products. In this review, we raise the potential implications of platelet microparticles in adverse transfusion reactions.
Plasmapheresis: recruitment, retention and flexible donors
Authors: Masser B. , Bagot K.
Published: April 2015

With worldwide demand for plasma‐derived products increasing, a critical question is how to effectively recruit and retain voluntary non‐remunerated (VNR) plasmapheresis donors? This review summarizes an emerging empirical literature and translates this into practical strategies for Blood Collection Agency (BCAs). We extend this to consider how ‘flexible’ donors – donors who move between panels as required to donate the right product at the right time – may be best cultivated by BCAs.
Megakaryopoiesis and ex vivo differentiation of stem cells into megakaryocytes and platelets
Authors: Pineault N. , Boisjoli G. J.
Published: April 2015

Blood agencies worldwide face the same recurring problem of enrolling healthy donors to produce platelet concentrates (PC) to meet the fluctuating demand. Research in stem cell biology has now made possible the production of culture‐derived platelets (CDP) raising the possibility of producing donor‐independent platelets. The aim of this paper was to first review known key concepts about megakaryopoiesis and second to describe efforts done in our laboratory and that of others for the establishment of culture processes for the production of megakaryocytes and platelets from cord blood haematopoietic stem and progenitor cells (HSPC). Recent progresses made with induced pluripotent stem cells (iPSCs) are also presented. Expansion of HSPCs and megakaryocytes can be accomplished by combining thrombopoietin (TPO) and a wide array of other cytokines. However, expansion of HSPCs ex vivo is associated with a rapid loss of megakaryocyte differentiation potential. Optimization of cytokine combinations and concentrations can improve yields and reduce consumption of growth factors. Moreover, the development of inducible megakaryocytic cell lines that can be triggered to undergo terminal megakaryocytic differentiation offers an independent solution to some of the problems associated with megakaryocyte production ex vivo. Functional characterization of platelets produced ex vivo has so far revealed that they form a heterogeneous population with some culture‐derived platelets (CDP) showing normal platelet properties and functions. In summary, functional CDPs can be produced in HSPC‐ and iPSC‐based cultures. Remaining challenges that need to be addressed before culture‐derived PCs can be used to complement blood‐derived PCs are also discussed.
Quality in blood components – it all starts with the donation
Authors: Armstrong V. A.
Published: April 2015

Blood transfusion is not risk free, so should only be prescribed when it is in the patient's best interest to do so. Blood establishments have a recognized obligation to promote optimal use of blood and blood components while minimizing risk to the health of the recipient. Processes are therefore focused on producing quality components that are efficacious and safe. In manufacturing processes, the quality of final products is heavily dependent on the quality and reliability of the starting materials, and therefore, control of these materials to reduce variation is a critical quality assurance activity. The starting material or primary product for the manufacture of blood components is the blood donation. If the quality of that donation is not assured, the efficacy and safety of the blood components manufactured from it will be potentially compromised no matter how good the rest of the manufacturing process may be. The challenge, however, is that blood is a biological material and collection is subject to a number of variations: Donations are collected from donors of various ages with different demographics, health profiles and behaviours. The donations have different characteristics, for example volume of donation, numbers of platelets, levels of immunoglobulin, blood group antibodies. The collection process depends largely on manual procedures with the exception of apheresis collections. Donations may be collected, stored and transported under varying environmental conditions. Because of these variations, controlling the quality and consistency of the primary blood donation can be more challenging than controlling starting material for an industry such as pharmaceutical manufacture. In recent years, there have been a number of developments aimed at improving the quality of the blood donation. These have largely focused on controlling and reducing variations in the process steps that are most likely to have an impact on quality or safety. These are called critical control points, and for the donation process, it includes the following: Selection of blood donors, Collection of the donation, Handling and storage of the donation, Transport of the donation to the processing centre. A number of the developments are new technologies that automate the critical control points as far as possible, such as decision support systems to improve the consistency of interpretation of donor selection guidelines, vein viewer systems that improve the venepuncture process and transport containers that can control temperatures. There have also been developments of internationally accepted component standards and principles of good manufacturing practices that provide the framework for quality in blood establishments and have been able to drive significant improvements in processes and component quality. In combination, these recent developments can provide a high degree of assurance that the starting point for the manufacture of safe and efficacious blood components will be a quality donation.
Regulation of cell therapy products in Korea
Authors: Han E. , Shin W.
Published: April 2015

Cell therapy products are regulated by the Ministry of Food and Drug Safety under the Pharmaceutical Affairs Act in Korea. Sixteen cell therapy products including three stem cells were approved for marketing authorization, and 155 clinical protocols have been approved. Due to the lack of complete understanding of various cellular product characteristics and limited experience on these products, there are many regulatory challenges to the reliable evaluation of safety and efficacy of these products. These challenges include, not limited to, lack of appropriate animal model for preclinical studies, difficulty in translating preclinical results to clinical design, short half life and limited amount autologous cell samples for testing, difficulty in maintaining blindness of control group in clinical study especially when invasive operation is required, concern over tumor or ectopic tissue formation and so on. For various regulatory challenges, a regulatory approach is the risk‐based, case‐by‐case and science‐based review with flexibility, balancing risk and benefits. In addition to periodic safety update reporting after marketing authorization, re‐examination of a drug and re‐evaluation of a drug exist to monitor the safety of an approved drug. There is a system for cell therapy product only, which requires mandatory safety reporting for every use of the approved cellular product for specific time period.
Making the right clinical decisions in component therapy
Authors: Allard S.
Published: April 2015

Rational clinical decision‐making is essential to guide appropriate transfusion practice. The use of evidence‐based guidelines needs a focused effort on various activities to promote implementation including training of all healthcare personnel involved, clinical audit and meaningful patient involvement. At present, there continues to be considerable inappropriate use of blood and components with variation in practice and targeted strategies are needed to improve practice supported by the use of information technology where available. There is a collective need to implement the principles of Patient Blood Management with an evidence‐based multidisciplinary approach to optimizing the care of all patients who might need transfusion with the timely use of alternatives wherever available.
An international survey of paediatric apheresis practice
Authors: Delaney M. , Capocelli K. E. , Eder A. F. , Schneiderman J. , Schwartz J. , Sloan S. R. , Wong E. C. C. , Kim H. C. ,   On behalf of the American Society of Apheresis, Applications Committee, Pediatric Subcommittee
Published: April 2015

Introduction

Paediatric apheresis (PA) has distinct characteristics compared to adult apheresis and requires specialized knowledge and experience to perform safely, particularly in low‐weight patients. As evidence‐based medicine advances the field of therapeutic apheresis, increased attention must be paid to paediatric patients with conditions for which apheresis is indicated.

Methods

An electronic survey of >5000 potential participants throughout the world was conducted to ascertain the scope and the current state of practice.

Results

The survey elicited 159 responses from 12 countries; 107 of the responses provided sufficient information for analysis. Participants performed an average of 176 PA procedures/year (range 1–2000). The types of PA procedures were therapeutic plasma exchange (TPE, 92% of centres), red cell exchange (RCE, 86%), leucocyte depletion (LD, 87%) and peripheral blood hematopoietic progenitor cell collection (HPC, 72%). More than 65% of the centres had treated children older than 5 years with PA. Many centres had also performed PA on younger children; 40% have treated patients <12 months of age; 61% had treated patients 1–5 years old. About 36% of centres reported that they would perform apheresis regardless of patient weight; 18% used a 5 kg threshold, 11% used 5–10 kg and 17% used 10 kg as their weight threshold.

Conclusion

This report is the largest single survey of centres performing PA. The results provide information about the scope and diversity of PA and identify areas where considerable variability in practice exists. Further exploration of these differences could establish best practices in PA through international research and collaboration.
Tissue typing and its role in transplantation
Authors: Nazahah M. , Koh M. B. C.
Published: April 2015

Transplantation of organ and haematopoietic stem cells is an established medical therapy, and success is dependent on finding the right donor bearing the appropriate human leucocyte antigen typing consisting mainly of class I (HLA‐A, HLA‐B and HLA‐C) and class II (class DP, DR and DQ) genes. These molecules engage with peptide fragments resulting in a complex interaction with dendritic cells and T cells. This plays an integral part in immune surveillance and modulates the recognition between self and nonself antigens. The principle of transplant biology is that any HLA disparity between donor and recipient triggers an ‘alloreactive response’ primarily mediated by T cells. This can result in graft‐versus‐host disease or graft‐versus‐leukaemia effect and has a significant role in graft rejection. Historically, HLA typing was performed via serological methods, but the advent of molecular techniques including DNA sequencing has allowed for higher resolution typing resulting in improvements in survival. This has historically been across 6 alleles (HLA‐A, HLA‐B and HLA‐DR) but has recently been expanded to include HLA‐C and HLA‐DQ. Consistent data have demonstrated the superiority in transplantation success with a 10/10 HLA‐matched donor. The stringent HLA matching in allogeneic stem cell transplantation (SCT) requires a careful selection of unrelated donors and may be more difficult for ethnic minority patients. To circumvent this, novel methods have been developed including alternative conditioning regimens, T‐cell depletion and haplo‐identical/mismatched transplants. The pioneering use of cord blood as a donor source has enabled transplants to be performed despite some degree of HLA mismatching.
Environmental variables and benthic macroinvertebrate assemblage in the headwater streams of an Afro‐tropical reservoir
Authors: Akindele Emmanuel O. , Olutona Godwin O.
Published: April 2015

The assemblage of benthic macroinvertebrates in relation to some selected environmental variables of the two headwater streams of Aiba Reservoir was studied from May 2013 to March 2014. This was with a view to assessing the health status and water quality of the streams, and comparing their taxa richness with similar studies on the reservoir and its out‐flowing stream. A total of 23 taxa were recorded in the study.
and
showed indirect relationships (P < 0.05) with bioindicators of good water quality, while dissolved oxygen (DO) showed indirect relationship (P < 0.05) with bioindicators of poor water quality. The streams were of poor biological water quality, and diversity indices revealed that they were polluted and unstable in habitat structure. Anthropogenic impacts at the upper reaches need to be mitigated and regular biomonitoring of the streams is of the essence, in order to conserve the integrity of the downstream reservoir.
Green and Ampt infiltration model extended beyond rain duration
Authors: Akan A. Osman , Atabay Serter
Published: April 2015

A simple method requiring only hand calculations is presented in this study that enables the use of the Green and Ampt infiltration model beyond the rain duration. The method takes into account that the runoff and infiltration processes continue for some period of time after the rain stops. Both the ground surface and subsurface characteristics are considered. A conjunctive overland flow‐infiltration mathematical model is employed for this purpose. A kinematic‐wave approach is used to model the overland flow, and the Green and Ampt equations are employed to calculate the infiltration rates. The governing equations are expressed and solved in terms of dimensionless parameters to enable the generalization of the results based on the principle of hydrologic similarity. A four‐point finite difference scheme is used to solve the governing equations. The results are presented in chart form. An example application of the proposed method is included.
Novel assessment of haemodynamic kinetics with acute exercise in a rat model of pulmonary arterial hypertension
Authors: Brown Mary Beth , Chingombe Tsungai J. , Zinn Abigail B. , Reddy Jagadeshwar G. , Novack Rachel A. , Cooney Sean A. , Fisher Amanda J. , Presson Robert G. , Lahm Tim , Petrache Irina
Published: April 2015

New Findings

What is the central question of this study?

The acute effect of exercise at moderately high intensity on already‐elevated pulmonary arterial pressures and right ventricular wall stress in a rat model of pulmonary arterial hypertension (PAH) is unknown.

What is the main finding and its importance?

We show, for the first time, that in a rat model of PAH, exercise induces an acute reduction in pulmonary artery pressure associated with lung endothelial nitric oxide synthase activation, without evidence of acute right ventricular inflammation or myocyte apoptosis. Haemodynamic measures obtained with traditional invasive methodology as well as novel implantable telemetry reveal an exercise‐induced ‘window’ of pulmonary hypertension alleviation, supporting future investigations of individualized exercise as therapy in PAH.

Exercise improves outcomes of multiple chronic conditions, but controversial results, including increased pulmonary artery (PA) pressure, have prevented its routine implementation in pulmonary arterial hypertension (PAH), an incurable disease that drastically reduces exercise tolerance. Individualized, optimized exercise prescription for PAH requires a better understanding of disease‐specific exercise responses. We investigated the acute impact of exercise on already‐elevated PA pressure and right ventricular (RV) wall stress and inflammation in a rat model of PAH (PAH group, n = 12) induced once by monocrotaline (50 mg kg−1, i.p.; 2 weeks), compared with healthy control animals (n = 8). Single bouts of exercise consisted of a 45 min treadmill run at 75% of individually determined aerobic capacity (). Immediately after exercise, measurements of RV systolic pressure and systemic pressure were made via jugular and carotid cannulation, and were followed by tissue collection. Monocrotaline induced moderate PAH, evidenced by RV hypertrophy, decreased , PA muscularization, and RV and skeletal muscle cytoplasmic glycolysis detected by increased expression of glucose transporter‐1. Acute exercise normalized the monocrotaline‐induced elevation in RV systolic pressure and augmented pulmonary endothelial nitric oxide synthase activation, without evidence of increased RV inflammation or apoptosis. Real‐time recordings of pulmonary and systemic pressures during and after single bouts of exercise made using novel implantable telemetry in the same animal for up to 11 weeks after monocrotaline (40 mg kg−1) corroborated the finding of acute PA pressure decreases with exercise in PAH. The PA pressure‐lowering effects of individualized exercise associated with RV‐neutral effects and increases in vasorelaxor signalling encourage further development of optimized exercise regimens as adjunctive PAH therapy.
Impairment of adenylyl cyclase‐mediated glutamatergic synaptic plasticity in the periaqueductal grey in a rat model of neuropathic pain
Authors: Ho Yu‐Cheng , Cheng Jen‐Kun , Chiou Lih‐Chu
Published: April 2015

Key points

Long‐lasting neuropathic pain has been attributed to elevated neuronal plasticity changes in spinal, peripheral and cortical levels. Here, we found that reduced neuronal plasticity in the ventrolateral periaqueductal grey (vlPAG), a midbrain region important for initiating descending pain inhibition, may also contribute to neuropathic pain.

Forskolin‐ and isoproterenol (isoprenaline)‐elicited EPSC potentiation was impaired in the vlPAG of a rat model of neuropathic pain induced by spinal nerve injury.

Down‐regulation of adenylyl cyclase–cAMP– PKA signalling, due to impaired adenylyl cyclase, but not phosphodiesterase, in glutamatergic terminals may contribute to the hypofunction of excitatory synaptic plasticity in the vlPAG of neuropathic rats and the subsequent descending pain inhibition, ultimately leading to long‐lasting neuropathic pain.

Our results suggest that drugs that activate adenylyl cyclase in the vlPAG have the potential for relieving neuropathic pain.

Neuropathic pain has been attributed to nerve injury‐induced elevation of peripheral neuronal discharges and spinal excitatory synaptic plasticity while little is known about the contribution of neuroplasticity changes in the brainstem. Here, we examined synaptic plasticity changes in the ventrolateral (vl) periaqueductal grey (PAG), a crucial midbrain region for initiating descending pain inhibition, in spinal nerve ligation (SNL)‐induced neuropathic rats. In vlPAG slices of sham‐operated rats, forskolin, an adenylyl cyclase (AC) activator, produced long‐lasting enhancement of EPSCs. This is a presynaptic effect since forskolin decreased the paired‐pulse ratio and failure rate of EPSCs, and increased the frequency, but not the amplitude, of miniature EPSCs. Forskolin‐induced EPSC potentiation was mimicked by a β‐adrenergic agonist (isoproterenol (isoprenaline)), and prevented by an AC inhibitor (SQ 22536) and a cAMP‐dependent protein kinase (PKA) inhibitor (H89), but not by a phosphodiesterase (PDE) inhibitor (Ro 20‐1724) or an A1‐adenosine antagonist (DPCPX). Both forskolin‐ and isoproterenol‐induced EPSC potentiation was impaired in PAG slices of SNL rats. The SNL group had lower AC, but not PDE, activity in PAG synaptosomes than the sham group. Conversely, IPSCs in vlPAG slices were not different between SNL and sham groups. Intra‐vlPAG microinjection of forskolin alleviated SNL‐induced mechanical allodynia in rats. These results suggest that SNL leads to inadequate descending pain inhibition resulting from impaired glutamatergic synaptic plasticity mediated by the AC–cAMP–PKA signalling cascade, possibly due to AC down‐regulation in the PAG, leading to long‐term neuropathic pain.
Development of a Soot Load Sensor Using Electrical Capacitance Imaging
Authors: Huq Ragibul , Anwar Sohel
Published: April 2015

This paper presents an innovative approach for measuring particulate matter deposition (soot load) in a diesel particulate filter (DPF) using electrical capacitance imaging. Emission regulations on diesel engines for gaseous as well as particulate matter (soot) emissions are getting stringent every few years by the environment regulatory agencies. Modern diesel engines are equipped with DPFs, as well as on-board technologies to evaluate the status of DPF, because complete knowledge of DPF soot load is very critical for robust and efficient operation of the engine exhaust after treatment system. In course of time, soot will be deposited inside the DPF which will clog the filter and generate a back pressure in the exhaust system, negatively impacting the fuel efficiency. To remove the soot build-up, regeneration (active or passive) of the DPF must be done as an engine exhaust after treatment process periodically. Since the regeneration process consumes fuel, a robust and efficient operation based on accurate knowledge of the soot load becomes essential in order to keep the fuel consumption at a minimum. In this paper, we propose a novel sensing method for a DPF that can measure in situ soot load using electrical capacitance imaging. Experimental results show that the proposed method offers an effective way to measure the soot load in DPF. The proposed method is expected to have a profound impact in improving overall DPF filtering efficiency and durability of a DPF through appropriate closed-loop regeneration operation.
Conductance fluctuations in graphene subjected to short-range disorder
Authors: Liu Bobo , Akis Richard , Ferry David K
Published: April 2015

Conductance fluctuations in graphene nanoribbons with a disordered, short-range potential are numerically studied. The authors carry out Fermi energy sweeps at different magnetic fields and magnetic field sweeps at a fixed Fermi energy to examine whether universality and ergodicity hold in graphene. The authors find that there is no universality of the fluctuations. The amplitude of fluctuations has a dependence on disorder strength. Further, Fermi energy sweeps have stronger fluctuation amplitudes than magnetic field sweeps, demonstrating a lack of ergodicity. In addition, the magnetic field does not significantly affect the fluctuation amplitude of Fermi energy sweeps.
Ultrashort echo‐time MRI versus CT for skull aberration correction in MR‐guided transcranial focused ultrasound: In vitro comparison on human calvaria
Authors: Miller G. Wilson , Eames Matthew , Snell John , Aubry Jean‐François
Published: April 2015

Purpose:

Transcranial magnetic resonance‐guided focused ultrasound (TcMRgFUS) brain treatment systems compensate for skull‐induced beam aberrations by adjusting the phase and amplitude of individual ultrasound transducer elements. These corrections are currently calculated based on a preacquired computed tomography (CT) scan of the patient's head. The purpose of the work presented here is to demonstrate the feasibility of using ultrashort echo‐time magnetic resonance imaging (UTE MRI) instead of CT to calculate and apply aberration corrections on a clinical TcMRgFUS system.

Methods:

Phantom experiments were performed in three ex‐vivo human skulls filled with tissue‐mimicking hydrogel. Each skull phantom was imaged with both CT and UTE MRI. The MR images were then segmented into “skull” and “not‐skull” pixels using a computationally efficient, threshold‐based algorithm, and the resulting 3D binary skull map was converted into a series of 2D virtual CT images. Each skull was mounted in the head transducer of a clinical TcMRgFUS system (ExAblate Neuro, Insightec, Israel), and transcranial sonications were performed using a power setting of approximately 750 acoustic watts at several different target locations within the electronic steering range of the transducer. Each target location was sonicated three times: once using aberration corrections calculated from the actual CT scan, once using corrections calculated from the MRI‐derived virtual CT scan, and once without applying any aberration correction. MR thermometry was performed in conjunction with each 10‐s sonication, and the highest single‐pixel temperature rise and surrounding‐pixel mean were recorded for each sonication.

Results:

The measured temperature rises were ∼45% larger for aberration‐corrected sonications than for noncorrected sonications. This improvement was highly significant (p < 10−4). The difference between the single‐pixel peak temperature rise and the surrounding‐pixel mean, which reflects the sharpness of the thermal focus, was also significantly larger for aberration‐corrected sonications. There was no significant difference between the sonication results achieved using CT‐based and MR‐based aberration correction.

Conclusions:

The authors have demonstrated that transcranial focal heating can be significantly improved in vitro by using UTE MRI to compute skull‐induced ultrasound aberration corrections. Their results suggest that UTE MRI could be used instead of CT to implement such corrections on current 0.7 MHz clinical TcMRgFUS devices. The MR image acquisition and segmentation procedure demonstrated here would add less than 15 min to a clinical MRgFUS treatment session.
Student Awareness of University Adventure Programs: Understanding Motivations and Constraints
Authors: Flood Joseph P. , Parker Christopher
Published: April 2015

Participation rates among college students in adventure programs (AP) have been problematic in recent years. While AP managers focus on the quality of programs offered to students, little effort has addressed reducing constraints to participation, improving program offerings, and effectively marketing AP at colleges and universities. The purpose of this investigation was to identify the constraints and motivations to AP participation. A survey was administered to 193 college students. Overall, respondents were motivated to participate in outdoor recreation activities that included males wanting to observe others, teach others, and experience thrills, while females wanted to be with companions and to receive physical and emotional benefits. Even though both males and females identified lack of time and money as major constraints, they also identified stress and demands of life as constraints. To enhance participation, AP managers need to emphasize the physical and psychological benefits that can potentially reduce stress.
Motivation for Participation in Campus Recreation Based on Activity Type
Authors: Beggs Brent , Nicholson Lindsey , Elkins Daniel , Dunleavy Sarah
Published: April 2015

In this study, we examined differences in leisure motivation on the basis of the type of campus recreational activity in which a student was engaged. Specifically, campus recreational activities included aquatics, group fitness, intramural sports, informal sports, and informal fitness. The Leisure Motivation Scale (Beard and Ragheb, 1983) was completed by subjects after they engaged in a campus recreation activity. A 95% confidence level was established a priori, but a Bonferroni adjustment resulted in α ≤ .0015. Results from an analysis of variance indicated differences between activity type. Subjects engaged in informal sports were less motivated by competency/mastery factors than those engaged in other campus recreation activities. In addition, stimulus avoidance was a less predominant motivator in subjects participating in intramural sports than in those involved in other types of programs. These results suggest that students engaged in different activities are motivated by different factors and have implications for campus recreation programmers and marketers as they design programs.
Adults' Motivation for Physical Activity: Differentiating Motives for Exercise, Sport, and Recreation
Authors: Ball James Warren , Bice Matthew R. , Parry Thomas
Published: April 2015

Physical inactivity continues to be a significant problem that adversely impacts adult health. An important construct to consider in researching adult physical activity adherence is motivation. Factors motivating participation in two types of physical activity, exercise and sport, have been compared; however, factors motivating participation in another type of physical activity, recreation, have often been left out of the comparison. The current study compared motivation to partake in physical activity among adults whose primary type of physical activity was exercise, sport, or recreation. Results indicate that participation motivation significantly varied among physical activity types (exercise, sport, and recreation). It was found that the participants who engaged in recreation as their primary form of physical activity and the participants who took part in exercise as their primary form of physical activity had motivations that were more similar to one another's than to those of the participants who use sport as their primary form of physical activity. Specifically, the findings suggest that participants who use exercise and recreation activities as their primary form of physical activity are motivated by more extrinsic constructs, compared to those who engage in sport as their primary form of physical activity. Findings provide insight that can be used to facilitate improved adherence to physical activity recommendations.
Migrated biliary stent causing perforation of sigmoid colon and pelvic abscess
Authors: Mady Raafat Fadly , Niaz Osamah Saad , Assal Mohamed Moustafa
Published: April 2015

Endoscopically placed biliary stents are a well-established procedure for the treatment of benign and malignant causes of obstructive jaundice. A plastic stent is usually inserted in patients with obstructive jaundice due to pancreatic cancer as a short-term procedure. Stent migration has been reported as a complication, although in most cases the stent will pass through or remain in the bowel lumen for a period of time. In rare cases, the stent may cause sigmoid perforation and pelvic abscess formation, especially in patients with sigmoid diverticulae or abdominal adhesions due to previous surgery. We present a patient with sigmoid perforation and pelvic abscess due to distal migration of a biliary stent placed to decompress a pancreatic head carcinoma.
Anti-VEGF therapy in a silicone oil-filled myopic eye with choroidal neovascularisation
Authors: Chhablani Jay , Narayanan Raja
Published: April 2015

A 33-year-old man presented with vision loss in his right eye due to rhegmatogenous retinal detachment, for which he underwent pars plana vitrectomy with silicone oil injection. Three months later, the patient presented with sudden vision loss. On examination, his visual acuity was 20/200 with presence of subretinal haemorrhage with attached retina and silicone oil in situ. Fluorescein angiography confirmed the diagnosis of choroidal neovascularisation (CNV). The patient underwent intravitreal ranibizumab injection (0.5 mg per 0.05 mL). He subsequently underwent oil removal along with intravitreal bevacizumab injection (1.25 mg per 0.05 mL). The CNV completely regressed. At 7 years follow-up, the patient's best corrected visual acuity was 20/50 with attached retina and macular scar due to regressed CNV. His other eye was within normal limits throughout the follow-up period. This unique case demonstrates the successful outcome of intravitreal ranibizumab injection in a silicone oil-filled eye with myopic CNV.
Construction of neighbourhood diversity indices with stem mapping data
Authors: Man Rongzhou , Yang Hua
Published: April 2015

Typical use of diversity indices in forest stands does not reflect within-stand variation in species and structure. Despite numerous efforts to design stand diversity indices that capture spatial variation in two- or three-dimensional space, the application of these indices is limited due to their complexity or lack of ecological relevance. In this research note, we illustrate the application of diversity indices at the neighbourhood scale using stem mapping data from a boreal mixedwood stand in northeastern Ontario, which was assessed before and after partial harvesting. Among the three diversity indices (Shannon species diversity, Shannon structural diversity by height class distribution, and structural diversity by height variation), neighbourhood structural diversity by height variation was less dependent on neighbourhood size (between 4 and 12 trees) and more sensitive to stand structural change than Shannon structural diversity by height class distribution. Despite general increases in Shannon species diversity and structural diversity by height variation at both stand and neighbourhood scales after the harvest — an indication of higher diversity — within-stand variation (coefficients of variation) in neighbourhood diversity values decreased, suggesting that residual stands were spatially more uniform after the harvest. Therefore, the neighbourhood diversity indices are useful for capturing spatial variation in species and structural diversity, especially in managed stands in which spatial distributions and patterns can be significantly modified by management interventions.
Mössbauer and magnetization studies of mechanically milled nanocrystalline Fe1–xAlx alloys
Authors: Rajan S. , Shukla R. , Kumar A. , Vyas A. , Khan S. , Brajpuriya R.
Published: April 2015

Changes in the magnetic behavior of Fe1–xAlx (x = 0.3, 0.4, 0.5, 0.6) powders during mechanical alloying have been studied. The ball milling process leads to formation of solid state reaction assisted by severe plastic deformation because of which crystallite size is reduced and as a result of which interesting magnetic properties are developed. The evolution of magnetic order in high-energy ball-milled Fe–Al solid solution is investigated using 57Fe Mössbauer spectroscopy and vibrating sample magnetometer. Mössbauer spectra and the hyperfine field distributions of all the samples show the presence of both magnetic and paramagnetic components in the samples. The corresponding bulk magnetization studies also show that the Al rich samples are also ferromagnetic, which can be attributed to the presence of disordered Fe-rich phases due to the non-equilibrium process of alloying. In Fe-rich samples, the formation of an off stoichiometric Fe3Al phase is favored while in the case of Al-rich samples both Al-rich phases and clustering of Fe and Al atoms are present. The systematic variation in the magnetic properties has been qualitatively correlated with the evolution of microstructure, reduction in grain size (obtained using transmission electron microscopy) and enhanced intergranular exchange coupling.
Moments in inclusive semileptonic B meson decays at the Belle experiment
Authors: Schwanda Christoph
Published: April 2015

Since my return to Austria in the year 2003, I have measured observables in inclusive B meson decays at the Belle experiment and worked together with theorists on the interpretation of these measurements in terms of the Cabibbo–Kobayashi–Maskawa matrix element |Vcb|. And in fact, only this memorial book project made me fully aware of Kolya Uraltsev's ground breaking theoretical contributions to this field. He was not a theorist who talked a lot to an experimentalist like me, and maybe this is not a bad thing for good science. I certainly remember his enthusiasm from conferences, e.g., when I was powerless to keep his presentation to the scheduled time as a session chair at the CKM2005 workshop in San Diego. Still I feel there is some amount of irony in the fact, that I know so little about a person whose work has been so decisive for my career in high energy physics.

To commemorate Kolya Uraltsev's pioneering work on inclusive semileptonic B meson decays B → Xcℓν and on the Heavy Quark Expansion (HQE), which has already been paid tribute to in other articles in this volume, I will review the measurement of the electron energy and the hadronic mass moments in B → Xcℓν decays performed at the Belle experiment. These measurements allow to both test his theoretical calculations and to extract |Vcb| and non-perturbative quantities, such as the b-quark mass, from his formulae.
Text Classification Using Compression-Based Dissimilarity Measures
Authors: Coutinho David Pereira , Figueiredo Mário A. T.
Published: April 2015

Arguably, the most difficult task in text classification is to choose an appropriate set of features that allows machine learning algorithms to provide accurate classification. Most state-of-the-art techniques for this task involve careful feature engineering and a pre-processing stage, which may be too expensive in the emerging context of massive collections of electronic texts. In this paper, we propose efficient methods for text classification based on information-theoretic dissimilarity measures, which are used to define dissimilarity-based representations. These methods dispense with any feature design or engineering, by mapping texts into a feature space using universal dissimilarity measures; in this space, classical classifiers (e.g. nearest neighbor or support vector machines) can then be used. The reported experimental evaluation of the proposed methods, on sentiment polarity analysis and authorship attribution problems, reveals that it approximates, sometimes even outperforms previous state-of-the-art techniques, despite being much simpler, in the sense that they do not require any text pre-processing or feature engineering.
A New Voltage-Mode Multifunctional Filter Using Only Two Voltage Followers and a Minimum Number of Passive Elements
Authors: Yucel Firat , Yuce Erkan
Published: April 2015

A new voltage-mode (VM) multifunctional filter using only two voltage followers (VFs), two resistors and two capacitors is proposed. The proposed filter with two inputs and two outputs can provide low-pass (LP) and high-pass (HP) responses. It does not need any critical passive component matching constraints. Additionally, it has low output impedances, low power dissipation and adequately low THD values. However, it does not have high input impedances; accordingly, it requires an extra VF to obtain high input impedance. A number of time domain and frequency domain simulations and experimental tests are performed to verify the claimed theory.
Learning Relational User Profiles and Recommending Items as Their Preferences Change
Authors: Siddiqui Zaigham Faraz , Tiakas Eleftherios , Symeonidis Panagiotis , Spiliopoulou Myra , Manolopoulos Yannis
Published: April 2015

Over the last decade a vast number of businesses have developed online e-shops in the web. These online stores are supported by sophisticated systems that manage the products and record the activity of customers. There exist many research works that strive to answer the question “what items are the customers going to like” given their historical profiles. However, most of these works do not take into account the time dimension and cannot respond efficiently when data are huge. In this paper, we study the problem of recommendations in the context of multi-relational stream mining. Our algorithm “xStreams” first separates customers based on their historical data into clusters. It then employs collaborative filtering (CF) to recommend new items to the customers based on their group similarity. To evaluate the working of xStreams, we use a multi-relational data generator for streams. We evaluate xStreams on real and synthetic datasets.
An Approach for the Incremental Export of Relational Databases into RDF Graphs
Authors: Konstantinou Nikolaos , Spanos Dimitrios-Emmanuel , Kouis Dimitris , Mitrou Nikolas
Published: April 2015

Several approaches have been proposed in the literature for offering RDF views over databases. In addition to these, a variety of tools exist that allow exporting database contents into RDF graphs. The approaches in the latter category have often been proved demonstrating better performance than the ones in the former. However, when database contents are exported into RDF, it is not always optimal or even necessary to export, or dump as this procedure is often called, the whole database contents every time. This paper investigates the problem of incremental generation and storage of the RDF graph that is the result of exporting relational database contents. In order to express mappings that associate tuples from the source database to triples in the resulting RDF graph, an implementation of the R2RML standard is subject to testing. Next, a methodology is proposed and described that enables incremental generation and storage of the RDF graph that originates from the source relational database contents. The performance of this methodology is assessed, through an extensive set of measurements. The paper concludes with a discussion regarding the authors' most important findings.
Building Domain Ontologies Out of Folksonomies and Linked Data
Authors: García-Silva Andrés , García-Castro Leyla Jael , García Alexander , Corcho Oscar
Published: April 2015

In this paper we propose an automatic method for building domain ontologies where we leverage the emerging vocabulary from social tagging systems, and the existing semantics in the Linked Open Data cloud to enrich semantically the terms that shape the domain ontology. We systematically capture a domain vocabulary by searching for relevant resources in the folksonomy graph using a spreading activation strategy. We use the vocabulary to identify domain classes and relationships among them by querying knowledge bases published as linked data. We present a case study in the financial domain where we experiment with different settings and show the feasibility of our approach using real folksonomy data.