bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal defocusing of intense hollow Gaussian laser beams in atmosphere
Authors: Sharma Ashutosh , Sodha Mahendra Singh , Misra Shikha , Mishra S.K.
Published: June 2013

In this paper, the authors have presented a paraxial theory for propagation of (1) Gaussian (2) dark hollow Gaussian high power laser beams in the atmosphere, considering the nonlinearity arising from the temperature variation along the wave-front. Specifically, the focusing parameter for both beams has been evaluated as a function of distance and initial beam power and width (corresponding to radiation of wavelengths 1.045 µ, 1.625 µ, and 2.141 µ in the water absorption window) for the maritime, desert, rural, and urban environments as modeled at NRL; the results have been presented in the dimensionless form. It is seen that in all four environments a dark hollow beam defocuses less than the corresponding Gaussian beam of same radius and power. It is suggested that this conclusion based on the paraxial theory be verified by numerical simulation.
SURGEONS’ VIEWS OF HEALTH TECHNOLOGY ASSESSMENT IN AUSTRALIA: ONLINE PILOT SURVEY
Authors: Gallego Gisselle , van Gool Kees , Casey Robert , Maddern Guy
Published: June 2013

Introduction:Many governments have introduced health technology assessment (HTA) as an important tool to manage the uptake and use of health-related technologies efficiently. Although surgeons play a central role in the uptake and diffusion of new technologies, little is known about their opinion and understanding of the HTA role and process.

Methods:A cross-sectional pilot study was conducted using an online questionnaire which was distributed to Fellows of the Royal Australasian College of Surgeons over a 4-week period. Information was sought about knowledge and views of the HTA process. Descriptive statistics were used to summarize the data, frequencies, and proportions were calculated.

Results:Sixty-two surgeons completed the survey; of these, 55 percent reported their primary work place as a public hospital. Twenty-four percent of the participants reported that they had never heard of the HTA agency and 60 percent reported that surgical procedures are most likely to be introduced in the Australian healthcare system at the public hospital level (which is beyond the HTA's scope and dealt with at a state level). However, 61 percent considered that decisions about funding and adoption of new technologies should take place at the national level.

Conclusions:This survey provides some evidence that many surgeons remain unaware of the federal government's HTA process but still value evidence-based information. In order for HTA to be an effective aid to rational adoption of health-related technologies, there is a need for an evidence-based approach that is integrated and is accepted and understood by the medical professions.
NEW ANTICOAGULANTS AS THROMBOPROPHYLAXIS AFTER TOTAL HIP OR KNEE REPLACEMENT
Authors: Hamidi Vida , Ringerike Tove , Hagen Gunhild , Reikvam Åsmund , Klemp Marianne
Published: June 2013

Objectives:Due to a high risk of thromboembolism in patients undergoing major orthopedic surgery, it has become standard practice to give thromboprophylactic treatment. We assessed the relative efficacy and cost-effectiveness of two new oral anticoagulants, rivaroxaban and dabigatran, relative to subcutaneous enoxaparin for the prevention of thromboembolism after total hip replacement (THR) and total knee replacement surgery (TKR).

Methods:We conducted a systematic review of the literature to assess efficacy and safety, and evaluated quality of documentation using GRADE. Cost-effectiveness was assessed by developing a decision model. The model combined two modules; a decision tree for the short-term prophylaxis and a Markov model for the long-term complications and survival gain.

Results:For rivaroxaban compared with enoxaparin, we found statistically significant decreases in deep vein thrombosis, but also a trend toward increased risk of major bleeding. For mortality and pulmonary embolism there were no statistically significant differences between the treatments. We did not find statistically significant differences between dabigatran and enoxaparin for our efficacy and safety outcomes. Assuming a willingness to pay of EUR62,500 per QALY, rivaroxaban following THR had a probability of 38 percent, and enoxaparin following TKR had a probability of 34 percent of being cost-effective. Clinical efficacy had the greatest impact on decision uncertainty.

Conclusions:Dabigatran and rivaroxaban are comparable with enoxaparin following THR and TKR regarding the efficacy and safety outcomes. However, there is great uncertainty regarding which strategy is the most cost-effective. More research on clinical efficacy of rivaroxaban and dabigatran is likely to change our results.
ASSESSING SEARCHES IN NICE SINGLE TECHNOLOGY APPRAISALS: PRACTICE AND CHECKLIST
Authors: Wong Ruth , Paisley Suzy , Carroll Christopher
Published: June 2013

Objectives: No guidelines exist in the approach that Evidence Review Groups (ERGs) should take to appraise search methodologies in the manufacturer's submission (MS) in Single Technology Appraisals (STA). As a result, ERGs are left to appraise searches using their own approach. This study investigates the limitations of manufacturers' search methodologies as critiqued by ERGs in published STA reports and to provide a recommended checklist.

Methods: Limitations from search critiques in 83 ERG reports published in the NIHR Web site between 2006 and May 2011 were extracted. The limitations were grouped into themes. Comparisons were made between limitations reported in the clinical effectiveness versus cost-effectiveness searches.

Results: Twelve themes were identified, six relating to the search strategy, source, limits, filters, translation, reporting, and missing studies. The search strategy theme contained the most limitations. Missing studies were frequently found by the ERG group in the clinical effectiveness searches. The omission of searches by manufacturers for unpublished and ongoing trials was frequently reported by the ERG. By contrast, failure of the manufacturer to report strategies was the most common limitation in the cost-effectiveness searches. Themes with the most frequent limitations in both types of searches are search strategy, reporting and source.

Conclusions: It is recommended that a checklist that has reporting, source and search strategy elements be used in the appraisal of manufacturer's searches during the STA process.
Serum leptin concentrations in relation to dietary patterns in Chinese men and women
Authors: Zuo Hui , Shi Zumin , Dai Yue , Yuan Baojun , Wu Gaolin , Luo Yazhou , Hussain Akhtar
Published: June 2013

Objective

The present study aimed to evaluate the independent associations between serum leptin concentration and dietary patterns in a Chinese population.

Design

A cross-sectional study.

Setting

Data obtained from the 2006 wave of the China Health and Nutrition Survey in Jiangsu Province, China.

Subjects

The sample contained 1061 Chinese adults (488 men and 573 women). BMI was calculated as a parameter of obesity. Factor analysis was used to derive dietary patterns. ANCOVA was performed to assess the associations between serum leptin concentration and the dietary patterns.

Results

Four dietary patterns were derived: Western, High-wheat, Traditional and Hedonic. The Western pattern (rich in meat, milk and cake) was significantly associated with a higher level of serum leptin in men and women, both in an unadjusted model (both P for trend < 0·001) and after adjusting for sex, age, income, total energy intake, physical activity, smoking status and BMI (P for trend = 0·007 for men and P for trend < 0·001 for women). The other three dietary patterns were not significantly associated with serum leptin after adjustment. Sensitivity analysis showed there was an interaction between age and the Western pattern in relation to leptin level. An interaction also existed between current smoking status and the Western pattern.

Conclusions

Serum leptin concentration was positively associated with the Western dietary pattern in a Chinese population independent of BMI, energy intake and other factors.
TOWARDS DIFFERENTIAL CALCULUS IN STRATIFIED GROUPS
Authors: MAGNANI VALENTINO
Published: June 2013

We study graded group-valued continuously differentiable mappings defined on stratified groups, where differentiability is understood with respect to the group structure. We characterize these mappings by a system of nonlinear first-order PDEs, establishing a quantitative estimate for their difference quotient. This provides us with a mean value estimate that allows us to prove both the inverse mapping theorem and the implicit function theorem. The latter theorem also relies on the fact that the differential admits a proper factorization of the domain into a suitable inner semidirect product. When this splitting property of the differential holds in the target group, then the inverse mapping theorem leads us to the rank theorem. Both implicit function theorem and rank theorem naturally introduce the classes of image sets and level sets. For commutative groups, these two classes of sets coincide and correspond to the usual submanifolds. In noncommutative groups, we have two distinct classes of intrinsic submanifolds. They constitute the so-called intrinsic graphs, that are defined with respect to the algebraic splitting and everywhere possess a unique metric tangent cone equipped with a natural group structure.
ROOTS OF DEHN TWISTS ABOUT SEPARATING CURVES
Authors: RAJEEVSARATHY KASHYAP
Published: June 2013

Let $C$ be a curve in a closed orientable surface $F$ of genus $g\geq 2$ that separates $F$ into subsurfaces $\widetilde {{F}_{i} } $ of genera ${g}_{i} $, for $i= 1, 2$. We study the set of roots in $\mathrm{Mod} (F)$ of the Dehn twist ${t}_{C} $ about $C$. All roots arise from pairs of ${C}_{{n}_{i} } $-actions on the $\widetilde {{F}_{i} } $, where $n= \mathrm{lcm} ({n}_{1} , {n}_{2} )$ is the degree of the root, that satisfy a certain compatibility condition. The ${C}_{{n}_{i} } $-actions are of a kind that we call nestled actions, and we classify them using tuples that we call data sets. The compatibility condition can be expressed by a simple formula, allowing a classification of all roots of ${t}_{C} $ by compatible pairs of data sets. We use these data set pairs to classify all roots for $g= 2$ and $g= 3$. We show that there is always a root of degree at least $2{g}^{2} + 2g$, while $n\leq 4{g}^{2} + 2g$. We also give some additional applications.
Propranolol reduces cognitive deficits, amyloid and tau pathology in Alzheimer's transgenic mice
Authors: Dobarro Marta , Gerenu Gorka , Ramírez María J
Published: June 2013

The efficacy of antihypertensive agents in Alzheimer's disease (AD) is controversial. It has been tested here whether some antihypertensive drugs might influence AD through mechanisms independent of blood pressure-lowering activity. The effects of treatment with the antihypertensive propranolol on cognition and AD-related markers have been studied in the Tg2576 mouse model of AD. Propranolol, at a lower dose than that used as antihypertensive (5 mg/kg, 6 wk), attenuated cognitive impairments shown by Tg2576 mice aged 9 months in the novel object recognition and fear conditioning tests. Propranolol was also able to counteract the increases in hippocampal levels of Aβ42 present in Tg2576 mice. This effect was accompanied by an increased expression of insulin degrading enzyme. Changes in markers of synaptic pathology, as shown by decreases in phosphorylation of Akt and in the expression of BDNF in Tg2676 mice, were also counteracted by propranolol treatment. Tau hyperphosphorylation shown by Tg2576 mice was also decreased in the hippocampus of propranolol-treated mice, an effect probably related to an increase of GSK3β phosphorylation (inactive form) and a decreased JNK1 expression. Overall, these data further strengthen the potential of propranolol as a therapeutic agent for AD.
Learning on the Wires: BYOD, Embedded Systems, Wireless Technologies and Cybercrime
Authors: Longo Brunella
Published: June 2013

This article aims to identify and define some of the legal issues, the computer misuses and the information misbehaviour associated with IT security that are increasingly a matter for civil litigation, criminal cases and national policy where fighting serious organised crime and cybercrime are concerned. The author, Brunella Longo, investigates this subject, suggests criteria and offers practical guidance for researching the issues. The article also includes references to relevant legislation, normative technical standards and best practices that have emerged as a result of corporate IT developments.
French Swiss physicians' attitude toward palliative sedation: Influence of prognosis and type of suffering
Authors: Beauverd M. , Bernard M. , Currat T. , Ducret S. , Foley R.A. , Borasio G.D. , Blondeau D. , Dumont S.
Published: June 2013

Objective:

Palliative sedation is a last resort medical act aimed at relieving intolerable suffering induced by intractable symptoms in patients at the end-of-life. This act is generally accepted as being medically indicated under certain circumstances. A controversy remains in the literature as to its ethical validity. There is a certain vagueness in the literature regarding the legitimacy of palliative sedation in cases of non-physical refractory symptoms, especially “existential suffering.” This pilot study aims to measure the influence of two independent variables (short/long prognosis and physical/existential suffering) on the physicians' attitudes toward palliative sedation (dependent variable).

Methods:

We used a 2 × 2 experimental design as described by Blondeau et al. Four clinical vignettes were developed (vignette 1: short prognosis/existential suffering; vignette 2: long prognosis/existential suffering; vignette 3: short prognosis/physical suffering; vignette 4: long prognosis/physical suffering). Each vignette presented a terminally ill patient with a summary description of his physical and psychological condition, medication, and family situation. The respondents' attitude towards sedation was assessed with a six-point Likert scale. A total of 240 vignettes were sent to selected Swiss physicians.

Results:

74 vignettes were completed (36%). The means scores for attitudes were 2.62 ± 2.06 (v1), 1.88 ± 1.54 (v2), 4.54 ± 1.67 (v3), and 4.75 ± 1.71 (v4). General linear model analyses indicated that only the type of suffering had a significant impact on the attitude towards sedation (F = 33.92, df = 1, p = 0.000).

Significance of the results:

The French Swiss physicians' attitude toward palliative sedation is more favorable in case of physical suffering than in existential suffering. These results are in line with those found in the study of Blondeau et al. with Canadian physicians and will be discussed in light of the arguments given by physicians to explain their decisions.
Brahms, Kierkegaard and Repetition: Three Intermezzi
Authors: Howell Tim
Published: June 2013

Schoenberg's ideas about ‘Brahms the progressive’ involve the close study of the composer's use of ‘developing variation’ technique, yet Brahms's music also contains a high incidence of repetition. In 1843, the Danish philosopher Søren Kierkegaard published a book called Repetition under the pseudonym, ‘Constantin Constantius’. As an encryption of his underlying philosophy, this pseudonym encapsulates both the constant nature of repetition – and its more subtle element of change. Thus stasis and dynamism, similarity and difference, are equally (and visibly) represented here. Kierkegaard's ideas find resonance within the late Brahms piano miniatures (for instance in the Drei Intermezzi, op. 117) where highly compressed formal structures exhibit differing kinds of repetitive processes. The temporal quality of repetition – the fact that experiencing the ‘same’ thing can only occur later on in time – makes this device more dynamic than it may at first appear. Such a view of repetition sits alongside Schoenberg's notion of ‘developing variation’ – the endless reshaping of a basic shape – but although they may have underlying connections, each is articulated in a different way. Studies of developing variation in Brahms are confined to pitch structures, interval patterns and rhythmic shapes, whereas considerations of repetition need to embrace issues of temporality, narrative and motion. Drawing upon Kierkegaard's philosophical distinction between re-experiencing something, rather than experiencing it again, allows repetition to become a catalyst for change. It may help to explain the expressive expansiveness of Brahms's structurally controlled late piano works.
Miniatures of a Monumentalist: Berlioz's Romances, 1842–1850
Authors: Rodgers Stephen
Published: June 2013

This article reassesses Berlioz's complex relationship to the French romance. Berlioz is often regarded as a musical revolutionary who made his mark writing massive, path-breaking symphonies – a far cry from the popular songs that became a staple of the bourgeois woman's salon. Yet he wrote romances throughout his life. How are we to understand these songs in the context of his overall output? What did the genre mean to him? How do his romances relate to the larger works on which his reputation rests? I explore these questions in relation to the romances he composed or revised between 1842 and 1850, a period often regarded as a fallow one for Berlioz but one that nonetheless saw a surge of songwriting activity. Drawing upon recent theories about the autobiographical construction of Berlioz's music, and considering when these songs were written or revised, to whom they were dedicated, what images were associated with them and how their texts relate to the events of Berlioz's biography, I argue that their conventionality belies a deeply personal resonance and a musical ingenuity uncommon to the romance genre. As a whole, these songs show Berlioz returning to an intimate and direct style during an especially introspective and nostalgic period of his life. Even more, they suggest that his urge toward self-reflection was not confined to the programmatic and the large-scale, and that his miniatures and monuments have more in common than one might think.
Ernest Newman's Draft of a Berlioz Biography (1899) and its Appropriation of Emile Hennequin's Style Theory
Authors: Watt Paul
Published: June 2013

Ernest Newman (1868–1959) first proposed a biography of Berlioz in the 1890s. A schedule for its research and writing was hatched, an agreement was made with a publisher for its manufacture, and Newman promptly set to work on the project. Alas, like so many other book projects Newman commenced in the 1890s, the Berlioz biography was never completed. Even though sketches or drafts of the book do not survive, there is plenty of evidence of the methodology and structure that Newman proposed for the book, for a work-in-progress article, ‘The prose of Berlioz,’ was published in theChordin June 1899. It is a remarkable essay for its engagement with Berlioz's prose works and for its theorizing on musical biography. I illustrate that Newman's biographical method was partly inspired by the work of Emile Hennequin (1858–93), and was an approach that Newman had previously used in some of his literary criticism. However, I argue that despite Newman's claim of Hennequin's influence, the article's wider influence came from a larger pool of writers working on style theory, including Walter Pater, Walter Raleigh and J.A. Symonds.
Residential Child Care in Malaysia: An Exploratory Qualitative Study of Caregiver–Child Interactions
Authors: Raj Stacey P. , Raval Vaishali V.
Published: June 2013

A number of children around the world require out-of-home care, and many children in Asia needing alternative care grow up in residential care homes. The impact and experience of being in residential care vary in different societies, and little is known about the lives and functioning of children in residential care in Malaysia ( Fulcher & Masu’d, 2001 ). Conceptualized within the developmental niche framework ( Super & Harkness, 1986 ), in this exploratory study, we used open-ended interviews and participant observation to describe the physical and social setting, caregiver goals, and child-rearing behaviors at a residential care home for orphaned, abandoned, and/or abused non-Muslim children in Kuala Lumpur. Caregivers emphasized the importance of academic achievement, respect for elders, and showing appreciation, and they were observed to use shaming, reference to caregiver sacrifice, and indirect praise to encourage those goals. Based on this exploratory study, directions for future research, practice, and policy pertaining to children in residential care in Malaysia are offered.
The Effects of a Family-Based Intervention (FBI) for Overweight/Obese Children on Health and Psychological Functioning
Authors: Lochrie Amanda S. , Wysocki Tim , Hossain Jobayer , Milkes Amy , Antal Holly , Buckloh Lisa , Canas J. Atilio , Bobo Elizabeth , Lang Jason
Published: June 2013

Obesity is the most prevalent chronic disease in childhood. There are many comorbidities associated with excess weight that are preventable with improved health. Prevention of medical comorbidities associated with obesity is critical and should begin early, particularly in childhood and preadolescence. This article examined immediate post-treatment and follow-up results of a randomized controlled trial of a 6-month lifestyle intervention involving diet, education, physical exercise, behavior change, and psychosocial methods for overweight or obese school-age children ages 8 to 11 to decrease risk factors associated with medical complications of obesity. Included are outcome data for youth participating in baseline, post-treatment, and 12-month follow-up evaluations. One hundred thirty overweight/obese youth were randomized to a control group or to a 14-session family-based group intervention over 6 months. Medical and psychosocial outcome data were measured at baseline, post-treatment, and follow-up. The intervention group (IG) showed a significant reduction in body mass index z-score (zBMI) and serum triglycerides, particularly for those in the treatment group who attended more sessions of the intervention. The treatment showed significant improvement in zBMI scores at post-treatment, and these results persisted after 12 months. There was no change observed in psychosocial outcome data. Obese children undergoing a family-based intervention (FBI) saw significant improvements in body mass index (BMI) and serum triglycerides that were sustained over 12 months following intervention. Future research should target retention and maintenance in FBIs, with the goal to prevent onset of medical morbidities associated with this disease.
Development of the Problem Solving Inventory With Italian Youth
Authors: Nota Laura , Heppner Puncky P. , Ginevra Maria Cristina , Ferrari Lea , Heppner Mary J. , Soresi Salvatore
Published: June 2013

The Problem Solving Inventory (PSI) is one of the most widely used applied problem-solving measures in the United States. The purpose of this research was to examine the psychometric properties of the PSI within Italian adolescent samples. Four separate data sets were used in this investigation involving 5,100 Italian adolescents. The first study revealed a similar, but slightly different, PSI factor structure with Italian youth. Using 2 samples, the second study confirmed the multidimensional structure of the PSI–Italian Adolescent and verified the invariance of the factorial structure across gender and age. The third study (fourth sample) established convergent validity estimates of the instrument as well as the stability of the factor structure over time. These results provide strong psychometric support for the PSI–Italian Adolescent among Italian youth.
Remotely Triggered Drug Release from Gold Nanoparticle-based Systems
Authors: Lim Eun-Kyung , Lee Kwangyeol , Huh Yong-Min , Haam Seungjoo
Published: June 2013

Nanoparticles are attractive drug carriers that can combine drug molecules and targeting moieties in order to improve treatment efficacy and reduce unwanted side effects. In addition, activatable nanoparticles may enable drug release in the target sites at accurate timings or conditions, in which drug discharge can be controlled by specific stimuli. Especially, gold nanoparticles provide a great opportunity as drug carriers because of the following advantageous features: i) simple formulation with various sizes and shapes and non-toxicity; ii) easy incorporation of targeting molecules, drugs or other therapeutic molecules on them; iii) triggered drug release by means of external or internal stimuli. In this chapter, we describe relevant examples of the preparation techniques and the performance of various types of gold nanoparticles for drug delivery as well as theranostics.
Smart Drug Delivery from Silica Nanoparticles
Authors: Colilla Montserrat , Vallet-Regí María
Published: June 2013

This chapter describes the different strategies developed so far by the biomedical scientific community aimed at designing smart drug-delivery nanosystems whose features and functionality can be tailored attending to specific clinical needs. Among inorganic carriers, we outline recent advances in mesoporous silica nanoparticles (MSNPs) as multi-functional nanoplatforms to design smart drug-delivery devices. MSNPs can be modified by targeting moieties to deliver specifically the desired drugs into unhealthy cells. Polymeric coatings can be used to provide the system of “stealth” properties and/or stimuli-responsive drug-delivery capability. The synergistic combination of magnetic nanoparticles (mNPs) with MSNPs provides the system with an added value, the possibility of using hyperthermia treatment combined with chemotherapy to increase the antitumor capability of the system or even performing magnetic resonance imaging. MSNPs can be functionalized with molecular nanogates capping the pore outlets to prevent premature release of the cargo before reaching the target cells. The application of a given stimulus (pH change, light, magnetic field, redox potential, etc.) would promote the nanogate removal, thus triggering the drug release. The achievements derived from in vitro and in vivo experiments, which are encouraging the biomedical community to move the MSNPs platforms into clinical trials, are also reviewed.
Smart Layer-by-Layer Assemblies for Drug Delivery
Authors: Pavlukhina Svetlana , Sukhishvili Svetlana
Published: June 2013

Layer-by-layer (LbL) assembly is an effective tool for development of surface coatings and capsules for localized, controlled delivery of bioactive molecules. Because of the unprecedented versatility of the technique, a broad range of nanoobjects, including molecules, particles, micelles, vesicles and others with diverse chemistry and architecture can be used as building blocks for LbL assemblies, opening various routes for inclusion and delivery of functional molecules to/from LbL films. Moreover, the LbL technique continues to show its power in constructing three-dimensional (3D) delivery containers, in which LbL walls can additionally control delivery of functional molecules incorporated in the capsule interior. In this chapter, we discuss recent progress in the use of LbL assemblies to control release of therapeutic compounds via diffusion, hydrolytic degradation, pH, ionic strength or temperature variations, application of light, ultrasound, electric and magnetic field stimuli, redox activation or biological stimuli.
Molecularly Imprinted Hydrogels for Affinity-controlled and Stimuli-responsive Drug Delivery
Authors: Alvarez-Lorenzo C. , González-Chomón C. , Concheiro A.
Published: June 2013

The performance of smart or intelligent hydrogels as drug-delivery systems (DDSs) can be notably improved if the network is endowed with high-affinity receptors for the therapeutic molecule. Conventional molecular imprinting technology aims to create tailored binding pockets (artificial receptors) in the structure of rigid polymers by means of a template polymerization, in which the target molecules themselves induce a specific arrangement of the functional monomers during polymer synthesis. Adaptation of this technology to hydrogel synthesis implicates the optimization of the imprinting pocket to be able to recover the high-affinity conformation when distorted by swelling or after the action of a stimulus. This chapter analyzes the implementation of the molecular imprinting technology to the synthesis of both non-responsive and responsive loosely cross-linked hydrogels, and provides recent examples of the suitability of the imprinted networks to attain affinity-controlled, activation-controlled or stimuli-triggered drug and protein release.
Biomolecule-sensitive Hydrogels
Authors: Miyata Takashi
Published: June 2013

Biomolecule-sensitive hydrogels that undergo volumetric changes in response to a target biomolecule such as glucose and proteins have become increasingly important because of their potential applications as smart biomaterials for constructing self-regulated drug-delivery systems (DDSs) and diagnostic systems. However, there have not been so many studies on biomolecule-sensitive hydrogels, due to difficulties in combining biomolecular recognition abilities with responsive functions within a hydrogel. This chapter introduces some strategies for designing biomolecule-sensitive hydrogels that exhibit swelling/shrinking behavior or sol-gel transition in response to the concentration of a target biomolecule. A standard strategy is to combine the molecular recognition events of biomolecules such as enzymes, lectins and antibodies with responsiveness of pH- and temperature-sensitive polymers. Another strategy uses biomolecular complexes like those of lectin-saccharide and antigen-antibody as dynamic cross-links of hydrogel networks. Designs of biomolecule-sensitive hydrogels will contribute significantly to develop smart DDSs in which specific amounts of drugs can be administered with monitoring specific biomolecules as diagnostic signals for several physiological changes. This chapter provides an overview of important researches about biomolecule-sensitive hydrogels for DDSs and diagnosis, focusing on saccharides, proteins, DNAs, etc. as target biomolecules.
Ultrasound-triggered Release from Micelles
Authors: Pitt William G. , Husseini Ghaleb A. , Kherbeck Laura N.
Published: June 2013

Ultrasound is an ideal trigger for site-actuated drug delivery because it can be focused through the skin to internal targets without surgery. Thermal or mechanical energy can be delivered via tissue heating or bubble cavitation, respectively. Bubble cavitation, which concentrates energy that can trigger drug release from carriers, occurs more readily at low frequencies and at bubble resonant frequencies. Other mechanical and physical consequences of cavitation are reviewed. Micelles are nanosized molecular assemblies of amphiphilic molecules that spontaneously form in aqueous solution and possess a hydrophobic core capable of sequestering hydrophobic drugs. Micelles have traditionally been used to increase the solubility of hydrophobic therapeutics for oral and intravenous administration. For ultrasonic drug delivery, polymeric micelles containing polyethylene oxide blocks are preferred because they have longer circulation time in vivo. Passive delivery occurs when micelles accumulate in tumor tissues that have malformed capillaries with porous walls. In active delivery targeting ligands are attached to the micelles, which directs their binding to specific cells. Actuated delivery occurs when ultrasound causes drug release from micelles and is attributed to bubble cavitation since the amount released correlates with acoustic signatures of cavitation. The mechanisms of ultrasonic drug release are discussed, including the prevalent theory that gas bubble cavitation events create high shear stress and shock waves that transiently perturb the structure of the micelles and allow drug to escape from the hydrophobic core. Ultrasound also perturbs cell membranes, rendering them more permeable to drug uptake. Tumors in rats and mice have been successfully treated using low-frequency ultrasound and chemotherapeutics in polymeric micelles. Ultrasonically activated drug delivery has great clinical potential.
Smart Polymersomes: Formation, Characterisation and Applications
Authors: Pearson R. T. , Avila-Olias M. , Joseph A. S. , Nyberg S. , Battaglia G.
Published: June 2013

The term polymersome, which refers to a fully synthetic polymeric vesicle, became commonplace around the turn of the millennium. Since then these highly intriguing structures have been at the center of multi-disciplinary research, bridging the fields of nanotechnology, chemistry, physics, biology, medicine and imaging and, more recently, pioneering the field of synthetic biology. As structures they offer greater control into understanding the relationship between amphiphile properties and membrane curvature. Moreover, as delivery vectors for therapeutic and diagnostic compounds they enable greater efficiency of current therapies and targeted delivery. With the rising costs of both healthcare and drug development, polymersomes and nanomedicine are well placed to combat these modern-day problems. This chapter provides an overview of the approaches to prepare and to characterize polymersomes as well as their applications in biomedicine, highlighting recent achievements in the stimuli-responsive drug delivery field.
Reduction-sensitive Nanosystems for Active Intracellular Drug Delivery
Authors: Cheng Ru , Meng Fenghua , Deng Chao , Zhong Zhiyuan
Published: June 2013

The past several years have witnessed explosive progress in reduction-sensitive nanosystems that are stable under physiological conditions, but rapidly destabilized under a reducing environment for “active” intra-cellular drug delivery. The uniqueness of the disulfide chemistry has enabled versatile design of smart nanosystems ranging from reduction-sensitive degradable micelles, polymersomes, nanogels and capsules to nanoparticles. This superior intra-cellular drug release approach has been shown to significantly enhance drug efficacy, overcome multi-drug resistance (MDR) and/or reduce drug- and carrier-associated side effects. In vivo studies have demonstrated that reduction-sensitive reversibly cross-linked nanosystems result in enhanced stability, longer circulation time, improved tumor-targetability and better therapeutic outcomes as compared to the non-cross-linked controls as well as to free drugs. It is anticipated that reduction-sensitive nanosystems will play a relevant role in the arena of targeted cancer therapy.
Bioresponsive Polyplexes and Micelleplexes
Authors: Alexander Cameron , Fernandez Trillo Francisco
Published: June 2013

The delivery of nucleic acids (NAs) is hindered by several factors, such as the size of the biomolecule (micron size for plasmid DNA), the presence of different biological barriers or the degradation of NAs. Most of these limitations are avoided by complexation with polycationic species, which collapse NAs into nanometer-sized polyplexes that can be efficiently internalized into the target cells. Because there are subtle changes in physiological conditions, such as the drop in pH at the endosome, or the increase in temperature in tumor tissue, stimuli responsive synthetic polymers are ideal candidates for the synthesis of efficient gene delivery vehicles. In this chapter, representative examples of “smart” polypexes that exploit these changes in physiological environment for the delivery of NAs are described, and the transfection efficiency of pH-, redox-, temperature- and light-responsive polyplexes is analyzed.
Pulse width modulation technique parameter selection with harmonic injection and frequency‐modulated triangular carrier
Authors: Meco‐Gutierrez Mario , Heredia‐Larrubia Juan‐Ramon , Perez‐Hidalgo Francisco , Ruiz‐Gonzalez Antonio , Vargas‐Merino Francisco
Published: June 2013

This study presents a very important feature of the technique of pulse width modulation (PWM) with injection of harmonic and triangular frequency carrier modulated in frequency. This technique is used to improve the quality of the output voltage signal of the power inverters controlled PWM. The purpose of this study is to show a new feature of controllability by the selection of different parameters. This allows multiple responses, from the point of view of the spectrum and the properties of the signal quality, with the same number of pulses per second, allowing the controllability of the modulated output signal. With this ability to control, it is possible to choose, for example, the total harmonic distortion of the signal output from the inverter, or the value of the fundamental term of voltage. It is also possible to select the low order harmonic, of interest for the selective reduction of harmonics. To show this feature, some examples have been developed with different number of pulses per period and with their corresponding parameter selection.
Fault diagnosis scheme for open‐circuit faults in field‐oriented control induction motor drives
Authors: Espinoza‐Trejo Diego Rivelino , Campos‐Delgado Daniel Ulises , Bossio Guillermo , Bárcenas Ernesto , Hernández‐Díez José Enrique , Lugo‐Cordero Luis Felipe
Published: June 2013

In this study, a new model‐based fault detection and isolation (FDI) strategy is proposed for field‐oriented control (FOC) induction motor (IM) drives. Actuator faults are addressed, and specifically, single open‐circuit faults are considered in this study. The residual signals are synthesised by taking the resulting closed‐loop dynamics when a FOC strategy is applied, that is, the residuals are referenced to the synchronous reference frame (dqe‐coordinates), which are generated by using a bank of variable structure observers to obtain a robust FDI scheme. Thus, subsystems sensitive to a specific fault, but decoupled from other faults are obtained in a natural way, where only two stator currents and the mechanical position are required for fault isolation purposes. Residual evaluation is carried out in the stator reference frame (dq‐coordinates) for the IM model, where the residual direction (angle) is employed to isolate a fault in each one of the six power switches in a voltage source inverter. In addition, the observer FDI scheme can be combined with a fault re‐configuration strategy in order to improve the reliability of the motor drive. Experimental results are illustrated for a three‐phase 3/4 HP IM drive at different reference frequencies and load torques with single open‐circuit faults that verify the ideas presented in this work.
New three‐phase discontinuous voltage mode Cuk power‐factor correction converter for low‐power applications
Authors: Foroozeshfar Reza , Adib Ehsan
Published: June 2013

In this study, a new three‐phase power‐factor correction (PFC) rectifier based on Cuk converter is introduced. The proposed converter operates in discontinuous voltage mode and therefore it has inherent PFC characteristics. Thus, it is not necessary to shape the input current using current shaping techniques. The proposed converter applies only one active switch and once the load is constant, the converter operates with constant duty cycle and constant switching frequency and thus, simple and low cost control and gate drive circuits are required. Also, the switch applied in this converter turns off under zero voltage switching condition. The proposed converter is analysed and theoretical analysis is justified using experimental results.
DC‐bus voltage control of grid‐connected voltage source converter by using space vector modulated direct power control under unbalanced network conditions
Authors: Xiao Lei , Huang Shoudao , Lu Kaiyuan
Published: June 2013

Unbalanced grid voltage will cause large dc‐bus voltage ripple and introduce high harmonic current components on the grid side. This will severely threaten the safety of the grid‐connected voltage source converter (VSC) and consequently, affect the healthy operation condition of the load. In this study, a new proportional‐integral‐resonant (PI‐RES) controller‐based, space vector modulated direct power control topology is proposed to suppress the dc‐bus voltage ripple and in the same time, controlling effectively the instantaneous power of the VSC. A special ac reactive power reference component is introduced in the controller, which is necessary in order to reduce the dc‐bus voltage ripple and active power harmonics at the same time. The proposed control topology is implemented in the lab. Simulation and experimental results are provided to validate its performance and the analysis presented in this study.
Voltage balancing scheme for flying capacitor multilevel converters
Authors: Salinas Fernando , González Mario A. , Escalante Miguel F.
Published: June 2013

This study proposes a voltage balancing scheme for flying capacitors multilevel converters. The strategy is based on the redundancy of switching states. By using analytic expressions, the authors study the balancing properties of each switching state. Then, based on such properties, the authors choose the switching state which drives the capacitor voltages towards their reference values, and simultaneously will ensure the desired voltage level. The method can be particulary attractive for those applications where the typical pulse‐width modulation control is not used, as direct torque control, hysteresis control and sliding‐modes control. Experimental results demonstrate the effectiveness of the proposed control scheme, in steady and dynamic conditions.
Series H‐bridge with stacked multicell inverter to quadruplicate voltage levels
Authors: Banaei Mohamad Reza , Jannati Oskuee Mohammad Reza , Mohajel Kazemi Farhad
Published: June 2013

In this study, a series H‐bridge with stacked multicell inverter (SHSI) is suggested which is commonly suitable for a high number of steps and for generating all levels at the output associated with a low number of circuit devices including switches and related gate driver circuits for each switch. The main advantages of the suggested topology compared with traditional flying capacitor multicell and stacked multicell (SM) inverters are increasing the number of output voltage levels and the root‐mean‐square value as much as four times, and doubles compared with mixed stacked multicell inverter. SHSI is compared with the mentioned structures improving the output voltage harmonic contents and decreasing the number and rating of components thereby reducing the cost and installation area and decreasing the stored energy and rating of flying capacitors. These sufficiencies are obtained by adding only four low‐frequency switches and a DC source to the traditional SM inverters structure. Provided simulation and experimental results certify the feasibility and good performance of the suggested inverter.
Analysis and implementation of an integrated electronic ballast for high‐intensity‐discharge lamps featuring high‐power factor
Authors: Cheng Hung‐Liang , Cheng Chun‐An , Chang Yong‐Nong , Tsai Kun‐Min
Published: June 2013

This paper proposes a high‐power‐factor electronic ballast for metal‐halide (MH) lamps. In the proposed circuit, two buck–boost converters and a buck converter are integrated with a full‐bridge inverter by sharing the four active switches of the full‐bridge inverter. Two active switches are switched at high frequencies, while the other two are switched at lower frequencies. The buck converter is used to step down the DC‐link voltage of the full‐bridge inverter and filter out the high‐frequency components to drive lamps with a low‐frequency square‐wave (LFSW) current. The buck–boost converters are operated at discontinuous‐conduction mode to perform the function of power‐factor correction (PFC) to ensure almost unity power factor at the input line. By tactful arrangement of diodes, the DC‐link capacitors are discharged in parallel; this helps to operate the high‐frequency active switches at a high duty ratio, achieving a small peak value of the PFC‐converter current and correspondingly smaller conduction losses. Detailed operation modes and the design equations are provided. A prototype electronic ballast for a 70 W MH lamp is built and tested. Experimental measurements have proven that the proposed electronic ballast has the advantages of high‐power factor and being free of acoustic resonance. By integrating the active switches of the converters and the inverter, the proposed electronic ballast is advantageous in terms of cost‐effectiveness and high energy‐conversion efficiency.
Family of zero‐voltage‐switching unregulated isolated step‐up DC–DC converters
Authors: Yao Zhilei , Xiao Lan
Published: June 2013

This study presents a family of zero‐voltage‐switching (ZVS) unregulated isolated step‐up DC–DC converters. All switches can realise ZVS using the magnetising current of the transformer. The ZVS unregulated isolated step‐up DC–DC converters are deduced from the basic ZVS cells using the magnetising current. The ZVS condition for the switches is given. The operating principle is analysed taking the ZVS push–pull forward (PPF) unregulated DC–DC converter as an example. The ZVS‐oriented parameter design and example are presented. Finally, the experimental results from a 1 kW ZVS PPF unregulated DC–DC converter support the theory.
GRATA: gradient‐based traffic‐aware routing for wireless sensor networks
Authors: Tan Do Duy , Quoc Dinh Nguyen , Kim Dong‐Seong
Published: June 2013

In this study, a distributed traffic‐aware routing scheme is proposed for a wireless sensor network with multiple sinks. In multi‐sink networks, traffic moving towards one sink may congest that moving towards others. The algorithm proposed here considers the traffic of surrounding neighbours before jumping to any sink. This is accomplished by building for each single sink, a gradient field and using gradient‐based search for routing. The gradient index of one node contains two parts. (i) The first represents the distance‐cost to travel, based on routing over lossy link) proposed by an IETF working group. (ii) The second contains the implicit traffic delay carried by the current holding node. Gradient field is built in distributed way and proven to free from loops. In a simulation, the authors show that this method of building gradient field routes balances the shortest path and possible congestion made by sinks, especially in heavy traffic networks, thereby reducing the overall end‐to‐end delay.
Relay augmentation for lifetime extension of wireless sensor networks
Authors: Brazil Marcus Nathan , Ras Charl John , Thomas Doreen Anne
Published: June 2013

The authors propose a novel relay augmentation strategy for extending the lifetime of a certain class of wireless sensor networks. In this class sensors are located at fixed and pre‐determined positions and all communication takes place through multi‐hop paths in a fixed routing tree rooted at the base station. It is assumed that no accumulation of data takes place along the communication paths and that there is no restriction on where additional relays may be located. Under these assumptions the optimal extension of network lifetime is modelled as the Euclidean k ‐bottleneck Steiner tree problem. Only two approximation algorithms for this NP‐hard problem exist in the literature: a minimum spanning tree heuristic (MSTH) with performance ratio 2, and a probabilistic 3‐regular hypergraph heuristic (3RHH) with performance ratio √3 + ɛ. The authors present a new iterative heuristic that incorporates MSTH and show through simulation that their algorithm performs better than MSTH in extending lifetime, and outperforms 3RHH in terms of efficiency.