bluuebunny/crossref_metadata_2025 huggingface dataset:
Social context, depression and the transition to motherhood
Authors: Lee Christina
Published: June 2011

Cultural assumptions about motherhood create an artificial dichotomy between the normal, happy, mother and the pathological experience of post‐partum depression. However, the evidence suggests that it is more reasonable to see post‐partum depression as one end of a continuum of normal adjustments to motherhood. While some postpartum psychiatric conditions do seem to be hormonally mediated, non‐psychotic postpartum depression is not qualitatively different from other forms of depression, and is best explained by inadequate social support, high workloads, and unrealistic expectations about motherhood. This paper reviews the evidence on post‐partum depression and on the normal experiences of new mothers, showing that new motherhood is a major life‐event which poses extensive adjustment problems for most women. Cultural expectations that family caring is naturally women's work, and that it is easy and stress free, mean that many mothers suffer a combination of work overload and guilt. A change in social expectations, greater involvement by fathers, and more flexible work practices to allow parents to care for their children would contribute greatly to the alleviation of distress in the post‐partum and early motherhood years.
Psychological distress and error making among junior house officers
Authors: Houston Diane M. , Allt Sophie K.
Published: June 2011

Objectives. The study examined the impact of beginning a junior house officer post on possible changes in psychological health and propensity to make errors. It was predicted that there would be a significant increase in psychological disturbance and error making following the onset of the post.

Design. Questionnaires were administered at two times—prior to and eight weeks after the beginning of a junior house officer post.

Methods. Thirty graduates of medicine/junior house officers were recruited from a university medical school in the UK. All participants completed the General Health Questionnaire and the Cognitive Failures Questionnaire at Times 1 and 2, as well as a Medical Errors Questionnaire at Time 2.

Results. Significant increases were found in reported levels of anxiety, insomnia and somatic symptoms. There were also significant increases in the number of errors that the respondents reported making in everyday life. These everyday errors were significantly related to the reported frequency of errors made in a medical context.

Conclusions. Despite recent revisions to the working hours and conditions of junior doctors in Britain, the respondents in this study were experiencing considerable increases in stressful symptoms and consequent increases in the number of errors they made. These findings suggest that further research and policy development is required to explore means of easing the transition to work for junior doctors.
Type A behaviour, problem‐solving style and health in male and female managers
Authors: Cassidy Tony , Dhillon Rhami
Published: June 2011

The relationship between Type A behaviour (TAB), problem‐solving style, and health was investigated in a sample of 79 middle managers (40 males and 39 females), using a questionnaire methodology. Health was divided into psychological well‐being, self‐rated physical healthiness, self‐rated frequency of illness and self‐rated health behaviour. Problem‐solving style was treated as a multidimensional construct and was measured in terms of six factors, helplessness, control, confidence, creativity, approach, and avoidance styles. Type As reported significantly more illness than Type Bs. In addition, a highly significant sex by TAB interaction was found on problem‐solving confidence and problem‐solving helplessness indicating that Type A females and Type B males were the more confident problem solvers and Type A females and Type B males felt less helpless in problem situations. On psychological well‐being, self‐rated healthiness and self‐rated health behaviour there were no differences between Type As and Type Bs. Multiple regression analysis showed that scores on TAB only accounted for a significant proportion of the variance in self‐rated frequency of illness. Problem‐solving style accounted for a significant proportion of the variance on all health measures.
Assessing short‐ and long‐term recovery from lumbar surgery with pre‐operative biographical, medical and psychological variables
Authors: de Groot Karina I. , Boeke Saskia , van den Berge Herbert J. , Duivenvoorden Hugo J. , Bonke Benno , Passchier Jan
Published: June 2011

Objective. The aim of this study was to investigate the joint association between biographical, medical and pre‐operative psychological variables on the one hand, and a range of short‐ and long‐term psychological and disorder‐specific outcome measures on the other hand, in patients undergoing lumbar surgery.

Design. Canonical correlations were used to determine which groups of pre‐operative variables were related to groups of outcome measures.

Methods. Participants were 126 patients undergoing lumbar surgery. On the day before surgery, information was obtained regarding age, sex, medical status variables, anxiety, fatigue, indices of pain and coping. Three days and three months post‐operatively, several aspects of recovery were measured.

Results. Female sex, number of analgesics taken, expected poor recovery according to the neurosurgeon, and pre‐operative anxiety were associated with poorer short‐term recovery. Reoperation, pre‐operative anxiety, fatigue and pain during daily activities were associated with poorer long‐term recovery.

Conclusions. The results suggest that the assessment of recovery after surgery might be improved by taking psychological variables into account, apart from biographical and medical variables. Checking patients' levels of pre‐operative anxiety, fatigue and pain might help hospital staff to detect patients who may be at risk of poor recovery in the long run. Applying psychological intervention techniques aimed at anxiety, fatigue and pain may facilitate recovery in such patients.
Repressors' responses to health‐related questionnaires
Authors: Myers Lynn B. , Vetere Arlene
Published: June 2011

Objectives. To investigate whether individuals who possess a repressive coping style (repressors) present themselves in an overly positive fashion on health‐related questionnaires.

Design. There were two cross‐sectional studies. Repressors (low trait anxiety, high defensiveness) were compared with (a) total non‐repressors and (b) a subset of non‐repressors which consisted of extreme scoring control groups on trait anxiety and defensiveness: low anxious, high anxious and defensive high anxious.

Methods. Participants completed three health‐related questionnaires: a measure of coping resources (the Coping Resources Inventory, CRI; Hammer & Marting, 1988) (Study 1); a measure of psychological symptomatology, the 12‐item General Health Questionnaire, GHQ‐12; Goldberg, 1992) (Study 2); and a measure of physical symptoms, the Pennebaker Inventory of Limbic Languidness (PILL; Pennebaker, 1982) (Study 2).

Results. In Study 1, repressors scored significantly higher on the CRI than total non‐repressors and all extreme scoring control groups. A similar pattern was shown for the subscales of the CRI. In Study 2, repressors scored significantly lower on the GHQ‐12 and the PILL, compared to total non‐repressors. Repressors scored significantly lower on the GHQ‐12 compared to two extreme control groups: high anxious and defensive high anxious, although there was no significant effect for the PILL.

Conclusions. The results support the hypothesis that repressors are presenting themselves in an overly positive fashion on self‐report health‐related measures.
Psychometric and clinical validity of the SF‐36 General Health Survey in the Whitehall II Study
Authors: Roberts Ron , Hemingway Harry , Marmot Michael
Published: June 2011

Objectives. To assess the internal consistency, test–retest reliability and factorial structure of the SF‐36. To examine the discriminant validity of the instrument in relation to measures of physical (angina, diabetes) and psychological health (chronic GHQ, alcohol problems as defined by CAGE score).

Design. A cross‐sectional survey design is used.

Methods. A questionnaire containing the SF‐36 was administered to a cohort of 10 308 civil servants aged 35–55 at baseline as part of the Whitehall II study of occupational and life‐style influences upon health. Administration of the SF‐36 was repeated on a subset of 289 participants four weeks later. Clinical groups were distinguished by self‐report measures of health.

Results. Data show high internal consistency (alpha .75–.85). Test‐reset reliability was poor for role limitations due to physical problems (.38), though acceptable for all other scales (range .60–.89). Orthogonal and oblique factor analyses confirm a two‐factor structure corresponding to dimensions of physical and psychological health. Validation of the scales against criterion groups defined on the basis of self‐reported health indicate that physical functioning, social functioning and general mental health have good discriminant validity.

Conclusions. The study provides further evidence that the SF‐36 may be used to investigate a range of physical and psychological problems even in relatively healthy populations. However some of the scales do not exhibit high levels of reliability and need careful consideration before being used. When physical and mental component summary scores are used, it is suggested that these are best derived from oblique factor solutions.
Self‐perception of communicative ability: Evaluation of a questionnaire completed by medical students and general practitioners
Authors: McManus I. C. , Kidd J. M. , Aldous I. R.
Published: June 2011

Objectives. To evaluate the psychometric properties of the 50‐item Communication Style Measure of Norton (1978), to assess the number of its subscales, and to provide normative descriptions of the subscales for providing feedback in teaching sessions.

Design. Questionnaire administered to 245 undergraduate medical students and 267 general practitioners.

Methods. Confirmatory and exploratory factor analysis of the structure of the 50‐item questionnaire. Regression analysis of scores on subscales in relation to age and sex.

Results. Norton's original 10‐factor structure for the questionnaire could not be sustained. Exploratory factor analysis suggested three factors which we labelled effective, dominant and non‐verbal, which were reliable (Cronbach's alpha = .79, .76 and .74), and which each showed different patterns of association with age and sex. On the basis of the factor analysis we also report a brief, easy to score questionnaire with 18 items, and we give normative distributions which might be useful for teaching in small groups.

Conclusions. Doctors and medical students found the Communication Style Measure easy to complete and to provide useful normative feedback on their self‐perceptions relative to those of other doctors and students. The 10 statistical factors proposed by Norton are not supported by the data, but three factors are readily identifiable.
Patient decision making: An evaluation of two different methods of presenting information about a screening test
Authors: Michie Susan , Smith Deana , Marteau Theresa M.
Published: June 2011

Andrew McClennan2

Objectives. To assess the impact upon women's decisions of presenting information about a screening test for Down syndrome in different ways.

Design. Random allocation to one of four conditions: simple leaflet only, simple leaflet + video, expanded leaflet, expanded leaflet + video.

Methods. Three hundred and twenty‐four women who were eligible for the test and for the study participated. Leaflets, and videos if appropriate, were given by midwives during booking consultations for participants to take home. The outcome measures were knowledge, change in knowledge, process of decision making, test uptake, anxiety, change in anxiety, and satisfaction with decision made.

Results. The interventions had no effect on any of the outcome measures.

Conclusions. These results show that the addition of a video or expanded leaflet does not confer any benefit in terms of knowledge, decision making or anxiety to women being offered serum screening for Down syndrome. This suggests that we should not accept at face value the seemingly positive contribution of videos as aids to information giving and decision making. The results also have implications for the way the decisionmaking process is conceptualized, an issue in urgent need of further study.
Personality and psychological distress in dysphonia
Authors: Deary Ian J. , Scott Shonagh , Wilson Isobel M. , White Aileen , MacKenzie Kenneth , Wilson Janet A.
Published: June 2011

Objectives. Personality traits and levels of psychological distress were studied in male and female patients with dysphonia. The contributions of medical referral and dysphonia were examined.

Design. A matched groups design with three control groups was used.

Methods. Seventy people with dysphonia, 90 people attending an otolaryngology clinic, 59 people attending general practice clinics, and 51 healthy people acted as participants. Each completed questionnaires of personality traits, alexithymia, health‐related coping strategies, mood (normal and pathological) and the past experience of medically unexplained symptoms.

Results. Women with dysphonia reported more psychological distress (anxiety and depression) and more previously unexplained medical symptoms than either healthy or general practice controls. Men with dysphonia exceeded only healthy controls on these factors. Personality and coping factors in men and women with dysphonia were largely unremarkable, an exception being that women with dysphonia tended to have higher neuroticism scores than general practice attendees.

Conclusions. Dysphonia is associated with psychological distress and a past history of experiencing unexplained medical symptoms. However, these characteristics are shared by general otolaryngology patients. This multiple control group study suggests that the problems of psychological distress may affect medical out‐patients in general. Studies of patient samples with medically unexplained symptoms that include only healthy controls or ‘organic’ out‐patient controls may be misleading. The phenomenon of medically unexplained symptoms, including dysphonia, imposes a large time and cost burden on health services and its further investigation would benefit from a collaboration between health psychologists and liaison psychiatrists.
Post‐operative adjustment to surgery resulting in the formation of a stoma: The importance of stoma‐related cognitions
Authors: White Craig A. , Unwin Jennifer C.
Published: June 2011

Objectives. This study aimed to determine the contribution made to psychological distress following stoma surgery by stoma‐related cognitions and ‘non‐cognitive’ factors such as age, marital status, physical symptoms and past psychiatric history.

Design. A questionnaire (Stoma Cognitions Questionnaire, SCQ) to measure negative stoma‐related beliefs was developed. The main contributors to psychological adjustment to stoma surgery were determined by interviewing patients post‐operatively.

Methods. Seventy‐nine patients who had undergone stoma surgery were interviewed at home between one and three months post‐operatively. Patients were asked about belief in negative stoma‐related cognitions, psychological distress, physical symptoms and demographic and medicosurgical information.

Results. The contribution of cognitions, demographic and medicosurgical information to variance in psychological outcome was examined using stepwise multiple regression. Responses to three SCQ items explained almost 60 per cent of the variability in psychological distress levels. Past psychiatric history and the presence of physical symptomatology were also significant contributors.

Conclusions. The presence of a past psychiatric history and physical complications/symptomatology are significantly related to post‐operative psychological distress following stoma surgery. Cognitions about physical integrity, impact on life and control are important in understanding adjustment to stoma surgery. These could be targeted for modification using cognitive therapy to reduce psychological distress among this patient group.
Association of psychosocial factors and dietary adherence in haemodialysis patients
Authors: McGee Hannah M. , Rushe Helena , Sheil Kim , Keogh Brian
Published: June 2011

Objectives. To examine the relationship of psychosocial factors to adherence to dietary restrictions of haemodialysis patients with the aim of identifying strategies to improve adherence.

Design. Cross‐sectional study with correlational analysis.

Methods. Interview and self‐completion questionnaire for all adult haemodialysis patients at one centre (N = 35; 92 per cent response). Psychosocial measures: Beck Depression Inventory (cognitive subset), Illness Effects Questionnaire, Renal Knowledge Questionnaire and Renal Adherence Attitudes Questionnaire. Adherence measures: biochemical indices, dietician rating, self‐report (Renal Adherence Behaviour Questionnaire).

Results. A minority reported significant psychological difficulties. High levels of non‐adherence were reported with little agreement among biochemical, dietician and self‐report formats. Demographic and clinical, more than psychological, indices were associated with variations in adherence.

Conclusions. Educational strategies may promote greater adherence but progress in this field is hampered by disagreement across different sources of assessment of adherence.
Cognitive, emotional and psychosomatic complaints and their relation to emotional status and personality following cardiac surgery
Authors: Vingerhoets Guy
Published: June 2011

Objectives. The study investigated the prevalence of cognitive, emotional, and psychosomatic complaints after uncomplicated cardiac surgery. In addition, we evaluated the relation between non‐cardiac complaints and emotional status and personality.

Design & Methods. Five to 12 months after elective bypass grafting 123 patients completed the Spielberger State Anxiety Inventory, the Beck Depression Inventory, the NEO Five‐Factor Inventory, and a subjective complaints questionnaire. A correlational design was employed to explore the relationships of these variables.

Results. Factor analyses of the complaints questionnaire revealed four cognitive and four emotional/psychosomatic dimensions. Seventy‐three per cent of the patients reported cognitive complaints, particularly problems with sustained and divided attention. Seventy‐eight per cent reported emotional or psychosomatic complaints, especially increased anxiety and emotional instability. Post‐operative complaints were significantly correlated with anxiety and depression, and with neuroticism. Stepwise regression analyses revealed that the occurrence of most subjective complaints was best predicted by self‐reported depression and anxiety. Self‐reported depression, anxiety and neuroticism contributed differently to different dimensions of subjective complaints.

Conclusions. Subjective post‐operative cognitive and emotional difficulties are very common after uncomplicated cardiac surgery. Self‐reported anxiety and depression are significantly associated with the occurrence of persistent subjective complaints. Although neuroticism also significantly contributes to the perceived post‐operative changes, most subjective complaints are best predicted by self‐reported depression and anxiety.
The subjective assessment of daytime cognitive dysfunction and motivation by insomniacs
Authors: Coyle Kieran
Published: June 2011

The research reported in this paper investigates insomniacs' self‐reports of daytime cognitive dysfunction and poor motivation as part of the aftermath of disturbed sleep. Results show that an insomniac group (N= 103) does not differ from normal sleepers (N = 40) on mean scale scores measuring everyday ‘attentional experiences’ (Davies et al., 1998), nor on measures of ‘competence’ or ‘aspiration’ at work and home. However, within the sleep‐disturbed group those with a higher level of anxiety and depression report significantly greater attentional dysfunction and lower levels of motivation. Further analyses show that those insomniacs with low levels of psychopathology do not differ from controls in self‐assessments of attention or motivation, although their sleep problem is as severe as those with high levels. The ‘next day’ effects that often form a major focus of presenting complaints of insomnia are thus not shared with those whose affect is more positive.
Effects of pre‐operative relaxation on post‐operative analgesia: Immediate increase and delayed reduction
Authors: Manyande Anne , Salmon Peter
Published: June 2011

Objectives. Pre‐operative relaxation has been reported to reduce pain complaints and analgesic requirement during convalescence on the surgical ward. These are questionable indices of recovery because the nurse‐patient relationship constrains patients' readiness to complain of pain. Analgesic requirement immediately postoperatively, before the patient returns to the ward, is more likely to reflect patients' pain state.

Design. A randomized comparison of effects of relaxation instructions on analgesic use immediately post‐operatively and subsequently, using background information about the hospital as a control procedure.

Methods. Patients (N=118) were randomly allocated to receive audiotaped relaxation instructions or a control tape before abdominal surgery. Analgesic usage was monitored during surgery, immediately after surgery (in the recovery room) and following return to the surgical ward. In addition, self‐report measures were used during recovery on the surgical ward.

Results. Relaxation reduced pain complaints and analgesic usage on the surgical ward by comparison with the information group, but led to increased analgesic administration by theatre staff immediately post‐operatively.

Conclusion. We suggest that effects on the surgical ward may have resulted from reduced willingness to complain of pain in the relaxed group and that, immediately post‐operatively, an increase in pain in this group may have resulted from an effect of relaxation to impair pre‐operative mental preparation. The results show the inherent ambiguity of analgesic use as an indicator of recovery.
Psychosocial determinants of ecstasy use in young people in the UK
Authors: Conner Mark , Sherlock Kellie , Orbell Sheina
Published: June 2011

Objectives. The present research aimed to examine the psychosocial determinants of ecstasy use in young people in the UK.

Design. Two studies applied the theory of planned behaviour (TPB) to understanding ecstasy use. In Study 1, students completed questionnaires measuring components of the TPB. In Study 2, a random sample of members of a nightclub completed measures of attitudinal ambivalence and components of the TPB in relation to taking ecstasy in the next two months. Reported use of ecstasy was assessed two months later.

Methods. Both studies employed self‐completion questionnaires. In Study 1 a single questionnaire was completed by 186 students. In Study 2 a first questionnaire was completed by 203 members of a nightclub and a second questionnaire two months later by 123 respondents.

Results. In Study 1, attitudes, subjective norms and perceived behavioural control accounted for 50 per cent of the variance in intentions. In Study 2, TPB components explained 63 per cent of the variance in intentions. Intentions and perceived control explained 55 per cent of the variance in subsequent ecstasy use. Attitudinal ambivalence moderated the intention‐behaviour relationship such that the impact of intentions on subsequent behaviour was significantly stronger for individuals with lower levels of ambivalence.

Conclusions. The TPB provided a good basis for understanding intentions and actual use of ecstasy in young people in the UK. The different beliefs of users and non‐users may form a useful basis for health education.
Acyclic nucleoside phosphonates: An unfinished story
Authors: De Clercq Erik
Published: June 2011

While cidofovir, adefovir and tenofovir are the three acyclic nucleoside phosphonates (ANPs) that have been licensed for clinical use (the latter as a single-, double- and triple-drug combination), there are many more ANPs that await their application for medical or veterinary use: (S)-HPMPA, (S)-HPMPDAP, cPrPMEDAP, (R)-HPMPO-DAPy, PMEO-DAPy, 5-X-PMEO-DAPy, (R)-PMPO-DAPy, (S)-HPMP-5-azaC, and cyclic (S)-HPMP-5-azaC, and alkoxyalkyl prodrugs thereof.
TWIN AND MIRROR SYMMETRIES FROM PRESYMMETRY
Authors: MATUTE ERNESTO A.
Published: June 2011

We argue that presymmetry, a hidden predynamical electroweak quark–lepton symmetry that explains the fractional charges and triplication of families, must be extended beyond the Standard Model as to have a residual presymmetry that embraces partner particles and includes the strong sector, so accounting for the twin or mirror partners proposed to alleviate the naturalness problem of the weak scale. It leads to the full duplication of fermions and gauge bosons of the Standard Model independently of the ultraviolet completion of the theory, even if the Higgs particle is discarded by experiment, which adds robustness to twin and mirror symmetries. The established connection is so strongly motivated that the search for twin or mirror matter becomes the possible test of presymmetry. If the physics beyond the Standard Model repairs its left–right asymmetry, mirror symmetry should be the one realized in nature.
MAGNONS AND DIPOLAR INTERACTIONS BETWEEN NEW HIGH SPIN MAGNETS
Authors: FALLOUL M. A. , EL HAFIDI M.
Published: June 2011

In this work, we elucidate the role of various microscopic interactions in high spin molecular nanomagnets. Starting from an effective spin Hamiltonian, we explain the origin and the importance of each coupling. We give special attention to exchange and dipole–dipole interactions between molecular magnets in a cubic lattice. The dispersion relation and magnetization behaviors are analyzed in the quantum magnons formalism taking into account the experimental reality and using common parameters values.
PHASE DIAGRAM OF ONE-DIMENSIONAL DEFORMED t–J1–J2 MODEL WITH FRUSTRATED EXCHANGE INTERACTION
Authors: DING HANQIN , ZHANG JUN
Published: June 2011

In this paper, we study the phase diagram of the one-dimensional deformed t–J1–J2 model with frustrated exchange interaction. The introduction of the deformed parameter ζ softens the strength of the induced four- and six-electron interactions caused by the no-double occupancy constraint. For the small ζ and in the weak-coupling regime, we use the bosonization approach and the renormalization group techniques to obtain the phase diagram, which is characterized by the singlet-(SS) and triplet-superconducting (TS), spin-density-wave (SDW) as well as bond-charge-density wave (BCDW) instabilities. The TS and BCDW phases are realized in the whole regime while the SDW and SS correlations depend on J2/J1 < (J2/J1)c or J2/J1 > (J2/J1)c, where (J2/J1)c = 1/3. Furthermore, the deformed model with ζ ≪ 1 is expected to adiabatically connect to the conventional t–J1–J2 model with ζ = 1.
A CUSTOMIZABLE FUZZY SYSTEM FOR OFFLINE HANDWRITTEN CHARACTER RECOGNITION
Authors: BATUWITA RUKSHAN , PALADE VASILE , BANDARA DHARMAPRIYA C.
Published: June 2011

Automated offline handwritten character recognition involves the development of computational methods that can generate descriptions of the handwritten objects from scanned digital images. This is a challenging computational task, due to the vast impreciseness associated with the handwritten patterns of different individuals. Therefore, to be successful, any solution should employ techniques that can effectively handle this imprecise knowledge. Fuzzy Logic, with its ability to deal with the impreciseness arisen due to lack of knowledge, could be successfully used to develop automated systems for handwritten character recognition. This paper presents an approach towards the development of a customizable fuzzy system for offline handwritten character recognition.
USING NEURAL NETWORKS FOR EARLY DETECTION OF UNSUCCESSFUL NEGOTIATION THREADS
Authors: ROUSSAKI IOANNA , PAPAIOANNOU IOANNIS , ANAGNOSTOU MILTIADES
Published: June 2011

Building agents that negotiate on behalf of their owners aiming to maximise their utility is a quite challenging research field in the artificial intelligence domain. In this paper, such agents are enhanced with techniques based on neural networks (NNs) to predict their opponents' negotiation behaviour, thus achieving more profitable results and better resource utilization. The NNs are used to early detect the cases where agreements are not achievable, supporting the decision of the agents to withdraw or not from the negotiation threads. The designed NN-assisted negotiation strategies have been evaluated via extensive experiments and are proven to be very useful.
PRODUCT FORMULATION WITH SURFACTANT NANOSTRUCTURES: LIQUID CRYSTALS, SOFT SOAP AND A PIECE OF CAKE
Authors: DUTTON HELEN , SIPERSTEIN FLOR , TIDDY GORDON
Published: June 2011

Surfactants self-associate in aqueous solutions to form micelles. Less well-known is that they form a wide range of liquid crystals — through self-association. These liquid crystals often occur in consumer products where they play an essential role in product stability and function. Some products are marketed in a liquid crystalline state although they are not recognized by the consumer (or, on occasion, by the manufacturer). This review describes the formation of micelles and the various liquid crystalline phases. These include lamellar, hexagonal, cubic and gel phases which have different long range structures but are based on micelles. The key factors linking surfactant molecular structure to liquid crystal architecture have been elucidated. These are the sizes of the surfactant hydrophobic tail(s) and head groups, together with the head group charge and the presence of any additives. Examples of liquid crystals in emulsion stabilization, household cleaners, conditioners, detergent liquid and some food are described.
NANOFABRICATION BY COVALENT MOLECULAR ASSEMBLY: A PATHWAY TO ROBUST STRUCTURES
Authors: PUNIREDDY S. , JAYARAMAN S. , GUPTA R. K. , YEONG S. H. , ZHANG F. , JIA Z. , SRINIVASAN M. P.
Published: June 2011

A wide range of new materials for many applications can be formed by controlling the composition and order of constituents at the molecular level. For systems thus engineered, ensuring chemical, thermal and mechanical robustness is a major challenge. Consequently, polyimides and other imide-containing materials are attractive as matrices for functional materials. We investigate the construction of functional nanostructures in organic/polymeric matrices with clearly demonstrated chemical, thermal and mechanical stability. Surface functionalization, layer-by-layer (LBL) assembly in various media (including supercritical), incorporation of functional moieties, molecular orientation, and interfacial reactions are areas of interest. We demonstrate the robustness of ultrathin film structures containing polyimides and oligoimides formed by LBL molecular assembly with inter-layer covalent links. Covalent bonding between the layers provides strength, while utilizing a supercritical medium for the processing, results in the deployment of a solvent-free environment and avoids problems related to residual solvent, thereby improving film quality when compared to conventional films.
MAXIMAL ENTANGLED FOUR-QUBIT STATE AND ITS PREPARATION IN CAVITY QED SYSTEM
Authors: XUE LI , WU LIE , CAI GEN-CHANG , JIANG NIAN-QUAN
Published: June 2011

In this paper, we explore the entanglement property of the nine families of four-qubit states and prove what are the maximally entangled four-qubit states. Then, we introduce a simple scheme to prepare this kind of states in cavity QED system.
ATOMIC WEHRL ENTROPY OF A SINGLE QUBIT SYSTEM
Authors: ABDEL-KHALEK S. , ABDEL-HAMEED H. F. , ABDEL-ATY M.
Published: June 2011

We propose the use of atomic Wehrl entropy associated to the reduced atomic density operator as an entanglement indicator of bipartite systems. This is applied to a two-level system (one single harmonically trapped ion) by taking into account the linear center-of-mass-motional degree of freedom. Detailed analytical and explicit expressions are given, taking into account different configurations. The results show the important roles played by the laser phase and initial state setting in the evolution of the atomic Q-function, atomic Wehrl entropy and marginal atomic Q-function. Our procedure of using atomic Wehrl entropy may be applied to a system with Hilbert space of high dimension.
FROZEN DISCORD IN NON-MARKOVIAN DEPHASING CHANNELS
Authors: MAZZOLA LAURA , PIILO JYRKI , MANISCALCO SABRINA
Published: June 2011

We investigate the dynamics of quantum and classical correlations in a system of two qubits under local colored-noise dephasing channels. The time evolution of a single qubit interacting with its own environment is described by a memory kernel non-Markovian master equation. The memory effects of the non-Markovian reservoirs introduce new features in the dynamics of quantum and classical correlations compared to the white noise Markovian case. Depending on the geometry of the initial state, the system can exhibit frozen discord and multiple sudden transitions between classical and quantum decoherence [L. Mazzola, J. Piilo and S. Maniscalco, Phys. Rev. Lett. 104 (2010) 200401]. We provide a geometric interpretation of those phenomena in terms of the distance of the state under investigation to its closest classical state in the Hilbert space of the system.
ENTANGLEMENT CAPABILITY OF NON-LOCAL HAMILTONIAN OF 2-QUTRIT SYSTEM
Authors: HU BAO-LIN , ZHAN YOU-BANG , HUA ZHENG-HE
Published: June 2011

In this paper, the entanglement capability of non-local Hamiltonian of 2-qutrit system is studied. The expression of the entanglement rate of non-local Hamiltonian of 2-qutrit system is derived, and the condition for maximal entanglement rate is determined. Analytic results show that, considering the entanglement rate, increasing the dimension of the system may not help to enhance the entanglement capability. The effect of auxiliary systems on the entanglement capability of 2-qutrit Hamiltonian is also discussed.
A ROBUST SCHEME FOR GENERATING A PECULIAR W-CLASS STATE WITH ATOMS TRAPPED IN SEPARATE CAVITIES
Authors: XIN BIN , XU PENG , ZHENG YI-ZHUANG
Published: June 2011

Utilizing coincidence measurement of photons leaking out of distinct cavities, we present a scheme for generating a peculiar W-class state which has recently been shown to be better than canonical W states for several quantum information processing tasks. In the traditional coincidence measurement, the probability of success can only be as high as 50% for each measurement. While under the condition of "weakly driven approach", the successful probability of coincidence measurement could achieve 100% in an ideal situation. Moreover, the scheme presented is robust and has high fidelity. The realization of teleportation with the peculiar W-class state has also been discussed briefly.
Impact of Gate and Passivation Structures on Current Collapse of AlGaN/GaN High-Electron-Mobility Transistors under Off-State-Bias Stress
Authors: Tajima Masafumi , Hashizume Tamotsu
Published: June 2011

Using a dual-gate structure, we have investigated the impact of gate-stress position on the current collapse behavior of AlGaN/GaN high-electron-mobility transistors (HEMTs) without surface passivation. When the gate-bias stress under the off state was applied to the additional gate between the main gate and the drain electrode, we observed a marked increase in on-resistance (RON). On the other hand, the off-state stress on the main gate itself caused a decrease in drain saturation current as well as an increase inRON. The calculation of electric field at the AlGaN surface showed that the field peaks existed at the gate edges on both the drain and source sides, probably causing electron charging at the AlGaN surface near both gate-edge areas. These results indicated that the off-state gate stress induces “virtual gates” in the gate edges expanding in both the drain and source directions. The impacts of device structures on the current collapse have been characterized, using Schottky-gate HEMTs with and without surface passivation and metal–oxide–semiconductor (MOS) gate HEMTs. The surface passivation and MOS-gate structure was effective in mitigating current collapse, which was explained in terms of surface state density, electric field strength, and gate leakage current.
Fabrication of ZnO Films Alloyed with LiGaO2 by RF-Magnetron Sputtering and Their Optical Property
Authors: Omata Takahisa , Tanaka Keizo , Otsuka-Yao-Matsuo Shinya
Published: June 2011

The alloyed thin films of ZnO with LiGaO2 were fabricated by an rf-magnetron sputtering technique using the target materials with various LiGaO2 concentrations. After optimizing the deposition conditions, such as sputtering atmosphere, applied rf-power and pressure, we successfully obtained almost stoichiometric x(LiGaO2)1/2·(1-x)ZnO alloyed films. All the obtained films were identified as the simple wurtzite phase. An immiscible region of 0.5 < x < 0.85 was concluded on the basis of a clear discontinuity in the variation of the lattice parameters and energy band gap as a function of the alloying level. For the lower LiGaO2 concentration films, the energy band gap increased with that increasing alloying level and it was widened up to 3.97 eV for x = 0.49, although a significant band gap bowing was observed. The broad absorption in the visible to near-infrared region attributable to the conduction electrons was clearly detected in the transmission spectra of the as-deposited films with 0 ≤x ≤0.5.
Improvement of Spatial Resolution in Raman Spectroscopy Selecting Measurement Area by Opaque Material Deposition
Authors: Takei Munehisa , Kosemura Daisuke , Akamatsu Hiroaki , Nagata Kohki , Ogura Atsushi
Published: June 2011

We have succeeded in the strain analysis beyond the spatial resolution in conventional Raman measurements, which can be achieved by selecting the strain-induced measurement area by an opaque material. Tungsten (W) film deposited by electron beam (EB)-assisted deposition was used for the opaque material in this study. The EB-W film has the properties of a relatively high absorption coefficient and a low density. These features give rise to shading of the excitation light without stress induction into Si. As a result, the wave number shift of 0.86 cm-1 was obtained in the Si substrate with 100-nm-wide space SiN pattern, whose value was higher than that obtained in conventional Raman measurements, 0.3–0.4 cm-1. Furthermore, the spatial resolution of Raman spectroscopy with the W film deposition was better than that of Raman spectroscopy with an immersion lens. We can say that the methodology is a promising candidate to measure strain in fine structures.
Aging Effect on Oxygen-Sensitive Electrical Resistance of SrTiO3 Thin Films
Authors: Hara Toru , Ishiguro Takashi , Shinozaki Kazuo
Published: June 2011

Our previous studies showed that SrTiO3-based thin films can be used to detect trace amounts of oxygen. The sensitivity to oxygen of the films was attributed to the polaronic nature of SrTiO3. In this study, it was observed that the application of an electric field resulted in a decrease in electrical resistance (hereafter, the aging effect) possibly in the same way as a dc electrical degradation in ceramic capacitors, which is due to the demixing of the oxygen vacancies (the electrical migration of oxygen vacancies leading to their pileup at the interface between SrTiO3 and electrodes). The sensitivity to oxygen of the films was maintained even after aging.
Intrinsic Effects of the Crystal Orientation Difference between (100) and (110) Silicon Substrates on Characteristics of High-k/Metal Gate Metal–Oxide–Semiconductor Field-Effect Transistors
Authors: Iijima Ryosuke , Edge Lisa F. , Bruley John , Paruchuri Vamsi , Takayanagi Mariko
Published: June 2011

A detailed comparison of high-k/metal gate stacks fabricated on the (100)- and (110)-oriented substrates has been made. We have verified that there is no structural difference between the gate stacks on the two substrates. The orientation independence of our gate stacks with the high-quality high-k/silicon interface for both substrates reveals the intrinsic effects of the crystal orientation on the high-k/metal gate devices. This is the first direct evidence that the inversion carrier quantization dependency on the crystal orientations dominates the total gate capacitance in the high-k/metal gate system. The analysis of the electron and hole mobilities highlights the fact that the scattering mechanisms inherent in the high-k/meta gate stacks limit the mobility enhancement and reduction driven by the effective mass change. No significant difference in the threshold voltage instability under the positive or negative gate bias stress is observed for the two substrates. Therefore, the optimized high-k/metal gate stacks enable us to gain certain benefits from the limited modulation of the mobility without sacrificing the stability of the threshold voltage.
Lateral Photocurrent Scanning of Donor and Acceptor Polymers on Graphene Coated Substrates
Authors: Mukhopadhyay Sabyasachi , Voggu Rakesh , Rao C. N. R. , Vidhyadhiraja N. S. , Narayan K. S.
Published: June 2011

Graphene provides a two-dimensional surface which can be utilized to interface with a variety of molecular species to modify opto-electronic processes. We use a scanning photocurrent technique to study the effect of graphene-coated anode substrates in semiconducting polymer device structures. The approach involves the measurement of the spatially varying photocurrent generated by an active semiconducting-polymer film sandwiched between a patterned substrate and a top electrode, where the narrow-incident light beam scans regions beyond the overlapping electrodes. We observe substantial difference in the spatial decay profile of the photocurrent upon introduction of graphene layers in the structure. Using simple circuit model and spreading impedance analysis we discuss the modification in carrier transport and recombination processes by underlying graphene layer in solar cell devices.
White Organic Light-Emitting Diodes Using Red-Fluorescent and Blue-Phosphorescent Emitters with Inducer Layer
Authors: Lee Sang Youn , Kim You Hyun , Song Wook , Mei Meng , Wood Richard , Kim Woo Young
Published: June 2011

We investigated the electroluminescent characteristics of new structural white organic light-emitting diodes (WOLEDs) including a double emitting layer with iridium(III) bis[(4,6-di-fluorophenyl)-pyridinato-N,C
2] picolinate (FIrpic) and 4-(dicyanomethy lene)-2-t-butyl-6(1,1,7,7-tetramethyliul-olidyl-9-enyl)-4H-pyran (DCJTB) as blue phosphorrescent dopant and red fluorescent dopant according to changing thickness of pure N,N '-dicarbazoly-3,5-benzene (mCP) as inducer layer. The optimized WOLED device with structure of indium tin oxide (ITO)/N,N '-bis(1-naphy1)-N,N '-dipheny1-1,1'-bipheny1-4-4'-diamine (NPB) (70 nm)/mCP doped with 10% FIrpic (20 nm)/mCP (3 nm)/tris(8-hydroxyquinolino)aluminum (Alq3) doped with 0.4% DCJTB (8 nm)/Alq3 (30 nm)/lithium quinolate (Liq) (2 nm)/aluminum (Al) (100 nm) shows the Commission Internationale de l'Eclairage, International Commission on Illumination (CIE
x,y
) coordinates of (0.34, 0.38) at a current density of 56.8 mA/cm2 and only varied within ±(0.01,0.02) over the brightness range from 10 to 6000 cd/m2.
Phase Modulation of Broadband Light Using Liquid-Crystal-on-Silicon Spatial Light Modulator
Authors: Takeno Kohei , Shirai Tomohiro
Published: June 2011

The influence of the illumination bandwidth on phase modulation using a liquid-crystal-on-silicon (LCOS) spatial light modulator (SLM) was evaluated. The maximum phase modulation for different wavelengths was determined using a Michelson interferometer. Phase modulation of the LCOS SLM exhibited good linearity for broadband light as well as light with a narrow bandwidth. Point spread functions (PSFs) formed via the LCOS SLM were measured for broadband illumination. Although PSF distribution expanded for the broader bandwidth, the full width at half-maximum (FWHM) of the center peak of the PSF remained the same for different bandwidths. Because of the preserved FWHM of the PSF, the resolution of imaging using the LCOS SLM was not influenced by the broadening of illumination bandwidth, but the expanded distribution contributed to the degradation of image contrast.
Rewritable Triple-Layer Phase-Change Optical Disk Providing 100 Gbyte Capacity
Authors: Nishihara Takashi , Tsuchino Akio , Tomekawa Yuko , Kusada Hideo , Kojima Rie , Yamada Noboru
Published: June 2011

A rewritable phase-change optical disk providing a large capacity of 100 Gbyte on a 120 mm disk was first demonstrated using the multilayer Blu-ray DiscTM (BD-XL) format. The doubled capacity of this optical disk compared with that of a conventional dual-layer disk was achieved firstly by stacking triple recording layers and secondly by increasing the recording capacity per layer from 25 to 33.4 Gbyte at 33.6%. The high transmittances of 50% (middle layer) and 60% (front layer) were achieved by thinning a Ge–Sb–Te phase-change film to 7.5 and 6 nm and also by thinning a Ag-alloy film to 9 and 7 nm, respectively. An additional TiO2-based film formed on the Ag-alloy film was effective in improving the transmittance at 3%, compared with the structure using a conventional TiO2 film. Furthermore, a transmittance-balanced structure was adopted for these layers in order to stabilize the recording-reading properties. To improve cyclability, ZrO2–Cr2O3-based interface films were provided on both sides of the phase-change film for the middle and front layers. The increase in recording capacity per layer was achieved by reducing the minimum mark length from 0.149 to 0.112 µm. Since the optical changes degrade with the reductions in the mark lengths and thicknesses of the Ge–Sb–Te and Ag-alloy films, a phase-change material with a GeTe-rich composition on a GeTe–Sb2Te3 pseudo-binary line was adopted for every layer to compensate it. It was confirmed that the sample disk successfully satisfies all the requirements of the BD-XL format.
Preparation and Structural Characterization of hcp and fcc Ni Epitaxial Thin Films on Ru Underlayers with Different Orientations
Authors: Higuchi Jumpei , Ohtake Mitsuru , Sato Yoichi , Nishiyama Tsutomu , Futamoto Masaaki
Published: June 2011

Ni epitaxial films are prepared by ultrahigh vacuum rf magnetron sputtering on Ru underlayers of (1120), (1100), and (0001) grown hetero-epitaxially on MgO single-crystal substrates of (100), (110), and (111) orientations, respectively. The film growth behavior and the crystallographic properties are studied by in-situ reflection high energy electron diffraction and pole figure X-ray diffraction. Metastable hcp-Ni(1120) and hcp-Ni(1100) crystals respectively nucleate on Ru(1120) and Ru(1100) underlayers, where the hcp crystals are stabilized through hetero-epitaxial growth. With increasing the film thickness, the hcp structure in the Ni films starts to transform into more stable fcc structure by atomic displacement parallel to the hcp(0001) close-packed plane. The resulting films consist of hcp and fcc crystals. On the other hand, only fcc crystal formation is observed for the Ni film grown on Ru(0001) underlayer.