bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical properties and inversion of conductivity type in nanocrystalline PbTe films
Authors: Dashevsky Z. , Kreizman R. , Dariel M. P.
Published: November 2005

This work is concerned with the effect of the nanostructure on the electrical conductivity of n-type In-doped PbTe thin films. Nanostructured thin films were prepared by varying the rate of nucleation as a function of the nature and temperature of the substrates. On low-temperature substrates, the increased rate of nucleation and the limited mobility of the atoms give rise to a nanostructured deposit with a 50 nm grain size. The broken bonds at the grain boundaries generate acceptor states in n-type films, capture electrons from the interior of the grains and give rise to p-type inversion layers between adjacent grains. In the nanostructured n-type films with the high density of grain boundaries, thermally activated hole conductivity becomes dominant and leads to its inversion from n to p type. The experimental results confirm the physical model put forward by Neustroev and Osipov [L. N. Neustroev and V. V. Osipov, Sov. Phys. Semicond. 20, 34 (1986)] regarding the creation of inversion channels (p-type conductivity), generated by the diffusion of oxygen along the grain boundaries of polycrystalline lead chalcogenide films. In the present case, these inversion channels appear on account of the acceptor states that have been generated at the grain boundaries of the nanostructured thin layers.
Role of evanescent waves in the positive and negative Goos-Hänchen shifts with left-handed material slabs
Authors: Chen Jianbing J. , Grzegorczyk Tomasz M. , Wu Bae-Ian , Kong Jin Au
Published: November 2005

A generalized analytical formulation for analyzing the Goos-Hänchen (GH) lateral shift direction is provided, from which we show that the phenomenon of both positive and negative GH shifts at different incident angles can be observed with left-handed material (LHM) slabs. The formulation also reveals that this unique phenomenon is related to the relative amplitudes of the growing and decaying evanescent waves inside the LHM slabs. The energy flux patterns with LHM slabs are further studied to show the influence of the evanescent waves on the GH shift direction change.
Room-temperature negative differential resistance in polymer tunnel diodes using a thin oxide layer and demonstration of threshold logic
Authors: Yoon Woo-Jun , Chung Sung-Yong , Berger Paul R. , Asar Sita M.
Published: November 2005

Conjugated polymers, with π molecular orbitals delocalized along the polymer chain, are useful organic semiconductors that provide the possibility of molecular electronics for low-power organic-based memory and logic. Quantum functional devices based upon carrier tunneling processes open vistas into very efficient and low-power consumption circuitry that would be ideal for these applications. We demonstrate here strong room temperature negative differential resistance (NDR) for poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylenevinylene] (MEH-PPV) polymer tunnel diodes (PTD) using a thin TiO2 tunneling layer (∼2–8nm) sandwiched between the MEH-PPV and the indium tin oxide anode. A key advantage is the pronounced NDR using a thick polymer layer with a large active area, circumnavigating the need for molecularly-sized junctions. Current-voltage measurements show large and reproducible NDR with a PVCR as high as 53 at room temperature. We also demonstrate basic logic circuit operation using a pair of these PTDs connected in series to form a monostable-bistable transition logic element (MOBILE) latch.
Effects of stoichiometry on electrical, optical, and structural properties of indium nitride
Authors: Ho J. C. , Specht P. , Yang Q. , Xu X. , Hao D. , Weber E. R.
Published: November 2005

A series of indium nitride (InN) epilayers with different excess indium (In) concentration are grown by plasma-assisted molecular-beam epitaxy on (0001) sapphire substrates. The increasing excess In concentration of the epilayers correlates with an increasing free-electron concentration and a decreasing electron mobility. Photoluminescence (PL) illustrates a 0.77–0.84eV transition for all samples with a redshift in the peak energy with increasing In concentration (for the highest free-electron concentration of 4×1021cm−3). This suggests that the ∼0.8eV PL transition is not consistent with the band-edge transition in InN. Moreover, an additional PL transition at 0.75eV along with the In clusters observed in transmission electron microscopy analysis are found only in the 29% excess In sample. This implies a relationship between the new PL transition and the presence of In clusters. Finally, secondary-ion mass spectrometry is used to verify that the contamination, especially hydrogen (H) and oxygen (O) impurities, has no influence on the redshift of the ∼0.8eV PL peaks and the existence of the additional 0.75eV peak in the sample containing In clusters.
Concentration dependence of the optical nonlinearity in extremely doped fluorinated organic copolymers
Authors: Belardini A. , Larciprete M. C. , Passeri D. , Michelotti F. , Ratsimihety A. , Rousseau A. , Menchini F. , Nichelatti E.
Published: November 2005

In this work we investigated the second-order nonlinear optical properties of a group of Disperse-Red-1-based electro-optic fluorinated copolymers, synthesized with two fluorinated monomers: the hexafluoroisopropyl alphafluoroacrylate monomer and the alphafluoroacrylate monomer bearing the Disperse Red 1 chromophore. Copolymers, with a concentration of chromophore substituted groups ranging from 46% to 75% molar, were synthesized and deposited as single films on glass substrates, for second-harmonic generation, and as sandwich structures with electrodes, for nonlinear ellipsometry measurements. For large concentrations of substituted groups, cracking of the films was observed and did not allow for any electro-optic characterization by nonlinear ellipsometry. The second-harmonic generation tensor main component d33 was retrieved by means of second-harmonic generation at λ=1064nm for each concentration. The results obtained for the copolymer with the lowest concentration are compared with those obtained by nonlinear ellipsometry at λ=1550nm and used as a calibration to infer information on the electro-optic properties at large concentrations. Stability of the poling-induced second-order nonlinear properties was checked by means of nonlinear ellipsometry. By using the temperature scanning technique, a depolarization temperature Tdep=124°C was measured, while the use of the isothermal relaxation technique allowed to observe two different decay regimes, a Vogel-Fulcher-Taman-Hesse one for temperatures above 110°C and an Arrhenius one for temperatures below 110°C, with activation energy EA≈58kcal∕mol.
Semianalytic approach for analyzing coupling issues in photonic crystal structures
Authors: Sanchis P. , Marti J. , Bienstman P. , Baets R.
Published: November 2005

A semianalytic approach based on previously derived closed-form expressions for the transmission and reflection matrices between a dielectric waveguide and a semi-infinite photonic crystal (PhC) waveguide is proposed for analyzing coupling issues in PhC structures. The proposed approach is based on an eigenmode expansion technique and introduces several advantages with respect to other conventional numerical methods such as a shorter computation time and the possibility to calculate parameters, such as the reflection into PhC structures, difficult to obtain with others methods. Two different examples are analyzed and results compared to finite-difference time-domain simulations to prove the usefulness of the proposed approach: (i) An especially designed two-defects configuration placed within a PhC taper to improve the coupling efficiency and (ii) a coupled-cavity waveguide coupled to a single-line defect PhC waveguide.
Room temperature emission at 1.6μm from InGaAs quantum dots capped with GaAsSb
Authors: Ripalda J. M. , Granados D. , González Y. , Sánchez A. M. , Molina S. I. , García J. M.
Published: November 2005

Room temperature photoluminescence at 1.6μm is demonstrated from InGaAs quantum dots capped with an 8nm GaAsSb quantum well. Results obtained from various sample structures are compared, including samples capped with GaAs. The observed redshift in GaAsSb capped samples is attributed to a type II band alignment and to a beneficial modification of growth kinetics during capping due to the presence of Sb. The sample structure is discussed on the basis of transmission electron microscopy results.
Effect of amorphous silicon carbide layer thickness on the passivation quality of crystalline silicon surface
Authors: Ferre R. , Martín I. , Vetter M. , Garín M. , Alcubilla R.
Published: November 2005

Surface passivation of p-type crystalline silicon wafers by means of phosphorus-doped hydrogenated amorphous silicon carbide films [a-SiCx(n):H] has been investigated. Particularly, we focused on the effects of layer thickness on the c-Si surface passivation quality resulting in the determination of the fixed charge density, Qf, within the a-SiCx(n):H film and the fundamental recombination of holes, Sp0. The main result is that surface recombination velocity decreases with film thickness up to 40nm and then saturates. The evolution of the interface parameters indicates that Qf could be located in a layer less than 10nm thick. In addition, Sp0 increases with thinner films probably due to different hydrogenation and saturation of interface dangling bonds during forming gas annealing.
Observation of interfacial void formation in bonded copper layers
Authors: Tan C. S. , Reif R. , Theodore N. D. , Pozder S.
Published: November 2005

Silicon wafers are bonded using copper (Cu) as the bonding medium and annealed to enhance the bonding strength at temperatures ranging from 300to400°C. The original bonding interface disappears and the Cu layers merge to form a single homogeneous layer. Cross-section transmission electron microscopy reveals a number of voids at the original bonding interface. It is observed that the size of these interfacial voids increases with bonding temperature. Thermal stress relaxation is proposed as the cause for interfacial void formation in the bonded Cu layers.
Interfacial potential and photoelectronic properties of manganite heterojunction La0.7Ce0.3MnO3∕SrTiO3:Nb
Authors: Sun J. R. , Shen B. G. , Tian H. F. , Li J. Q. , Weng Y. X.
Published: November 2005

The interfacial potential and photoelectronic properties of a heterojunction composed of La0.7Ce0.3MnO3 and SrTiO3:Nb have been experimentally studied. A two-dimensional spatial distribution of the electrostatic potential across the La0.7Ce0.3MnO3∕SrTiO3:Nb interface is obtained by the holography technique of the transmission electron microscope, which reveals the presence of a depletion layer of 8 nm in thickness at 120 K and 3 nm at 296 K and a built-in electric field within this layer. Consequently, a complex yet significant photovoltaic effect is observed. It is found that the transient photocurrent is composed of two distinctive processes with the charging-like behavior, and the time constants are surprisingly larger than that expected for a photoelectronic process, ∼30 and ∼260μs, respectively. It seems to be an intrinsic property of the manganite junction, and has nothing to do with external circuit and thermolelectric effect arising from light illumination.
Fringing-field minimization in liquid-crystal-based high-resolution switchable gratings
Authors: Gu Lanlan , Chen Xiaonan , Jiang Wei , Howley Brie , Chen Ray T.
Published: November 2005

A liquid-crystal (LC)-based high-resolution switchable grating is proposed by using a double-sided structure, where striped electrodes are patterned on both sides of the LC cell. A unique biasing configuration is employed to successfully minimize the distortion of the LC director profile due to the fringing-field effects under two-dimensional electric fields. A first order diffraction angle of 14.5° with a diffraction efficiency of 33% for transmission light at 1.55μm is experimentally achieved. This result approaches the theoretical upper limit of 33.8% for a sinusoidal phase grating. The device efficiency is enhanced 80 times compared to a conventional single-sided device. Experimental results indicate the tolerance of electrode misalignment is 2μm.
A note on spectral energy transfer for multiscale eddy viscosity models in large-eddy simulations
Authors: Walters K. , Bhushan S.
Published: November 2005

The multiscale approach to large-eddy simulation has shown potential to yield improved results over conventional eddy viscosity implementations with a relatively small increase in computational expense. Several variants of the modeled subgrid stress have been proposed, but no conclusions have been drawn regarding which formulations are the most accurate or physically appropriate. This Brief Communication presents a case for choosing a particular form for the subgrid stress tensor, based on relatively simple energy transfer concepts and inertial subrange scaling laws. It is proposed that two requirements should be satisfied. First, that the eddy viscosity depend only on the portion of the resolved energy spectrum near the filter cutoff, and second, that the modeled stress tensor permit energy transfer from the low wave-number modes to the subgrid scales. The result is a “small-large” multiscale variant for the subgrid stress. Results are presented for isotropic decaying turbulence and a transitioning planar jet case.
Nonlocal analysis of the Reynolds stress in turbulent shear flow
Authors: Hamba Fujihiro
Published: November 2005

An exact expression for the Reynolds stress is derived using the response function for the velocity fluctuation. The nonlocal eddy viscosity in the expression represents a contribution to the Reynolds stress by the mean velocity gradient at remote points in space and time. A direct numerical simulation of channel flow is conducted to validate the nonlocal expression. The transport equations for the velocity and the response function are numerically solved to evaluate the nonlocal eddy viscosity; it is shown that the nonlocal expression is accurate for both normal and shear stresses. A local expression for the Reynolds stress is also evaluated and reveals that the local approximation is not accurate enough near the wall. Analysis using the nonlocal expression is shown to be useful for obtaining a better understanding of turbulent shear flow.
Improved treatment of triple-probe data for determination of electron temperature
Authors: Qin Yunwen
Published: November 2005

A triple-probe array is intensively used for diagnosing electron temperature and density of edge plasma in tokamaks. Up to now, electron temperature Te has been calculated with the approximate relation Te≈Vd2∕ln2 in the constraint of Vd3⩾2Te, where Vd3 is the applied voltage between two probes and Vd2 is the voltage between positively biased and floating probes. This approach may cause a maximum error of 18.3% in Te. According to the triple-probe principle, the electron temperature Te satisfies an algebra equation. This article presents the numerical solution of the equation in the form Te=Vd2∕f(Vd3∕Vd2), where the increasing function f(ξ) approaches ln2 as a limit. A fitting formula for f(ξ) is proposed. The error of the approximation is lower than 0.7% for ξ⩾2.5, which covers the useful region for diagnostic, and lower than 6% for 2.001<ξ<2.5. The formula Te=Te(Vd2,Vd3) obtained in this way may improve the treatment of triple-probe data.
Clock signal requirement for high-frequency, high dynamic range acquisition systems
Authors: Viščor Ivo , Halámek Josef , Villa Marco
Published: November 2005

Analog-to-digital converters (ADC’s) are increasingly replacing mixers in frequency conversion schemes. To achieve superior performances, in terms of bandwidth and dynamic range, a nearly ideal ADC clock is needed, with a spectral purity higher than the reference signal of the classical mixing scheme. These requirements of spectral purity for the ADC clock are discussed by analyzing in detail the nonuniform sampling process and by characterizing an actual acquisition system. The effect of clock phase imperfections on the output is proportional to the input frequency over sampling frequency ratio. Moreover, at the output we may have a multiple folding of the phase jitter spectrum. These effects are illustrated by three sets of measurements performed using our system: transfer of spurious clock components, aliasing of these components, and transfer of clock phase noise.
A compact nanopositioning stage with high vibrational eigenfrequencies
Authors: Ball S. J. , Folsom C. , McLean A. B.
Published: November 2005

A compact nanopositioning stage is described that has high vibrational eigenfrequencies and is, therefore, insensitive to external vibrations. The high eigenfrequencies are produced by a rigid structure that is designed so that it does not degrade the motional performance of the stage. Preliminary performance evaluations are presented. We describe how a positioning stage of this type could be used as an integral part of a proximal probe.
Guided-wave near-infrared detector in polycrystalline germanium on silicon
Authors: Colace Lorenzo , Masini Gianlorenzo , Assanto Gaetano
Published: November 2005

Using a guided wave configuration, we demonstrate a novel polyGe-on-Si heterostructure photodetector realized on a silicon-on-insulator by a low deposition temperature process. Without further detector optimization, at 1.55μm we measured wall-plug responsivities as high as 15mA∕W with an effective responsivity in excess of 300mA∕W. Device operation was demonstrated up to 2.5Gbit∕s.
Shape-induced ferromagnetic ordering in a triangular array of magnetized disks
Authors: Beleggia M. , Zhu Y. , Tandon S. , De Graef M.
Published: November 2005

A magnetic transition induced by shape anisotropy, geometry, and dipolar interactions has been found in a system of three single domain thin disks. The phase transition occurs only when the disks are in close proximity, and for a narrow range of aspect ratios. Near the transition, the system has an abrupt change from a closure-domain state with zero net magnetization to a magnetized state. The transition can be detected by changes in the hysteresis loops. Micromagnetic simulations with realistic parameters confirm the establishment of ferromagnetic ordering.
Effect of elastic anisotropy on contact stiffness in resonance ultrasound microscopy
Authors: Tian Jiayong , Ogi Hirotsugu , Hirao Masahiko
Published: November 2005

The classical Hertzian-contact theory for an isotropic material has been adopted to simplify quantitative evaluation of local elastic modulus by resonance-ultrasound microscopy (RUM). However, the validity of this simplified model must be confirmed because most materials show elastic anisotropy in small regions. This study investigates the influence of the elastic anisotropy of the tip and the specimen on the determination of the local elastic modulus in RUM by introducing the Hertzian-contact stiffness for orthorhombic materials. Numerical results reveal that specimen anisotropy significantly affects the contact stiffness and the quantitative evaluation of local elastic modulus even for specimens with weak anisotropy when we consider the anisotropy of the oscillator tip in RUM.
Evaluation of an ethnic media campaign on patterns of HIV testing among people from culturally and linguistically diverse backgrounds in Australia
Authors: McMahon Tadgh , Fairley Christopher K. , Donovan Basil , Wan Lilian , Quin John
Published: November 2005

Objective: To evaluate a 2-week pilot ethnic media campaign that was implemented in 14 languages to promote awareness of HIV/AIDS and HIV testing among selected non-English speaking populations in Australia in November/ December 2000. Methods: The main outcome measure was clinic attendances for the purpose of HIV testing by individuals from the target populations at one of three public sexual health clinics in Sydney and Melbourne prior to and immediately after the campaign. Results: The number of HIV tests on members of the 14 target language communities attending the clinics almost doubled from 66 to 122 tests. However, as a proportion of the total number of HIV tests performed at the three clinics this increase was not significant (16.3% to 18.8%; P = 0.31). For both periods in 2000 the proportion of HIV tests that were performed on members of the target language group were higher than during a 1999 comparison period (10.5%, both P < 0.01). Conclusions and implications: This study did not demonstrate a significant increase in testing attributable to the pilot intervention. A larger campaign, with a more extensive evaluation, would probably be needed to demonstrate a measurable effect.
Testing men who have sex with men for Neisseria gonorrhoeae and Chlamydia trachomatis prior to the introduction of guidelines at an STD clinic in Melbourne
Authors: Lister N. A. , Smith A. , Read T. , Fairley C. K.
Published: November 2005

Background: Guidelines for testing men who have sex with men (MSM) were published in 2002. They did not recommend asymptomatic screening for urethral gonorrhoea or pharyngeal screening for chlamydia. To determine if these guidelines were appropriate, we audited gonorrhoea and chlamydia testing of MSM at our centre. Methods: We carried out two audits at our Centre between August 2001 to July 2002. The first was an audit of testing MSM for gonorrhoea and/ or chlamydia over 12 days. The second was an audit of all positive tests over this 12-month period for gonorrhoea or chlamydia among MSM. Results: During the 12 selected days 89 of 286 men tested (31%) were MSM. Among the MSM testing positive for gonorrhoea and/ or chlamydia infection (15, 17%), symptomatic urethral infection was the most common (n = 8). No rectal and pharyngeal infections had site-specific symptoms. Based on the guidelines, 100 of the 334 tests ordered (30%) were not recommended according to the guidelines, and none of these 100 tests yielded a positive result. Over the 12-month audit period, 135 MSM were diagnosed with gonorrhoea and/ or chlamydia. For gonorrhoea, site specific symptoms were present in 42 of 43 cases of urethral infection (98%), six of 23 cases of rectal infection (26%), and no cases of pharyngeal infection had symptoms. For chlamydia, site-specific symptoms were present in 29 of 48 cases of urethral infection (60%), six of 33 cases of rectal infection (18%), and in one of the two cases of pharyngeal chlamydia identified. A substantial proportion of cases occurred in clients with HIV infection (21, 16%). Conclusions: These findings strongly support screening among MSM and in particular not testing asymptomatic MSM for urethral gonorrhoea or any MSM for pharyngeal Chlamydia.
A comparison of first-void urine, self-administered low vaginal swab, self-inserted tampon, and endocervical swab using PCR tests for the detection of infection with Chlamydia trachomatis
Authors: Chandeying V. , Lamlertkittikul S. , Skov S.
Published: November 2005

Background: Polymerase chain reaction (PCR) tests, AMPLICOR, Roche Diagnostics, were shown to be an acceptable and sensitive method of detecting Chlamydia trachomatis infection. The PCR test's ability to evaluate different specimen types is worth determining, as well as the acceptability to Thai women of the self-collection of samples. Methods: Of the 1011 subjects interviewed, 953/1011 subjects (94.3%) agreed to self-test, 523 were commercial sex workers (CSWs) and 430 were outpatient women (OPW). More than half [570/953 (59.8%)] participated in the four-specimen collection, to be tested by PCR for C. trachomatis. Specimens were collected via first-void urine (FVU), self-administered low vaginal swab (LVS), self-inserted tampon, and endocervical swab (ES). The majority, 906/953 subjects (95.1%), had only three methods of specimen collection, LVS being excluded. Results: The prevalence of positive C. trachomatis detection among the CSWs/ OPW was 17.6/7.2%, 15.6/5.4%, 12.8/4.2%, and 11.6/5.7% using tampons, LVS, FUV, and ES collection methods respectively. Tampons were used to compare results from other specimen types in both groups. Significantly more OPWs were willing to use a tampon for repeat specimen collection (85.1%) than were the CSWs (62.3%). Willingness to use a LVS again was not significant, 75.2% in outpatient women and 74% in CSWs. Conclusions: Tampon and LVS, self-collection methods are acceptable to women in Thailand and are a good alternative method for detection of C. trachomatis.
Virological significance, prevalence and genetic basis of hypersusceptibility to nonnucleoside reverse transcriptase inhibitors
Authors: Tachedjian Gilda , Mijch Anne
Published: November 2005

Nonnucleoside reverse transcriptase inhibitors (NNRTI) are used to treat HIV-infected individuals in combination with nucleoside analogues (NRTI) and protease inhibitors. Long-term treatment with antiretroviral agents results in the emergence of strains with decreased susceptibility (resistance) to the drugs and is one of the major factors in loss of drug efficacy. Conversely, there have been recent reports of HIV strains with increased susceptibility (hypersusceptibility) to NNRTIs. These isolates emerge in patients on long-term antiretroviral therapy particularly in individuals receiving NRTIs. The prevalence of NNRTI hypersusceptibility ranges between 17.5 and 50% in NRTI-treatment experienced compared to 10% in NRTI-naïve patients. There is an inverse correlation between NNRTI hypersusceptibility and phenotypic NRTI resistance and a direct correlation between the number of NRTI resistance mutations present in the HIV reverse transcriptase. Re-sensitisation of phenotypic NNRTI resistance has been reported by NRTI mutations and is not likely to be detected using genotypic resistance assays. Recent studies demonstrate that NNRTI hypersusceptible virus at baseline is likely to predict better virological outcomes in patients on NNRTI-based salvage regimens compared to patients with NNRTI susceptible virus. These studies have implications for the sequence of antiretroviral drug use where patients may benefit from NRTI therapy before the introduction of NNRTIs, however more studies are needed to examine this treatment rationale.
HIV in prison: what are the risks and what can be done?
Authors: Hellard M. E. , Aitken C. K.
Published: November 2005

Prisons are recognised worldwide as important sites for transmission of blood-borne viruses (BBVs). There are two reasons why transmission risks in prison are higher than in the community. First, in most western countries, many prison entrants have histories of injecting drug use, and thus already have high prevalences of BBVs. Second, the lack or under-supply of preventive measures (such as clean needle and syringes or condoms) in most prisons, combined with extreme social conditions, creates extra opportunities for BBV transmission. HIV prevalence in prisoners in more developed countries ranges from 0.2% in Australia to over 10% in some European nations. There are case reports of HIV being transmitted by sharing injecting equipment and sexual activity. Tattooing has been reported as a risk factor for the transmission of BBVs in prison. Access to condoms and needle and syringe programmes in prisons is extremely limited, despite success when they have been introduced. The vast majority of prison inmates are incarcerated for only a few months before returning to the community, thus they are, over the long term, more appropriately regarded as ‘citizens’ than ‘prisoners’. Public health policy must involve all sections of the community, including prison inmates, if we are to reduce transmission of HIV and other BBVs.
Erectile function of Chinese men with schizophrenia in psychiatric out-patient clinics and their attitude towards treatment
Authors: Ng M. L. , Ho R.
Published: November 2005

Background: Antipsychotics had been shown to cause erectile dysfunction (ED). This study aims to determine the rate and degree of ED in Chinese males who had chronic schizophrenia and were taking antipsychotic agents for at least four weeks in an outpatient psychiatric clinic in Hong Kong. Method: Seventy Chinese males with chronic schizophrenia attending the clinic were surveyed on the five aspects of erectile function using the International Index of Erectile Function Scale (IIEF-15). Their attitude on receiving treatment for any ED was also elicited using a standard attitude questionnaire. Results: Fifty-eight per cent of married subjects had an IIEF-15 score below the cut off point for normal erectile function, although married subjects had a higher mean score than the single or divorced subjects. There was no significant difference in total IIEF-15 score between subjects on different antipsychotics. The score also showed no significant correlation with the duration of medication. Most subjects preferred psychotherapy to sildenafil for treatment of their sexual dysfunction. Conclusion: The majority of Chinese males with schizophrenia and maintained on antipsychotic drugs in the outpatient clinic had sub-optimal erectile function. Psychological management was the treatment of choice for their dysfunction.
The use of growth factors and cytokines to treat opportunistic infections in HIV-1 disease
Authors: Jaworowski Anthony , Maslin Clare L.V. , Wesselingh Steven L.
Published: November 2005

The success of highly active antiretroviral therapy (HAART) in reducing AIDS-related mortality means that in regions where HAART is available, HIV infection may now be regarded as a chronic disease. However the inability of HAART to eliminate HIV-1 from various anatomical and cellular reservoirs within the body means that HIV-infected individuals require life-long treatment with therapy that can have significant side effects. Management of HIV disease is therefore increasingly focused on drug-related toxicities and the improvement of current HAART regimens. Here we review the potential use of immunomodulatory cytokines to directly or indirectly stimulate the mononuclear phagocyte system as adjuncts to current HIV treatment as well as their use in the management of opportunistic infections in individuals who develop immunodeficiency. We argue that cytokines, which stimulate mononuclear phagocyte activity against opportunistic pathogens, may be useful for the treatment of individuals who develop recurrent opportunistic infections. Cytokines may act synergistically with antimicrobial agents to improve outcomes, which is of particular importance since recurrent infections frequently result in resistance to standard antimicrobial treatments. Before their use can be advocated however, given their toxicity and significant cost, the potential benefits of cytokines must be demonstrated in larger clinical trials.
Intersex embodiment: when health care means maintaining binary sexes
Authors: Roen Katrina
Published: November 2005

The treatments carried out with intersex children for the purpose of helping them live in a normatively gendered world have raised increasing levels of controversy in the past decade. This paper outlines key debates that are taking place highlighting the relevance of critical approaches to evidence. It points to the value of working across disciplines and epistemological frameworks in order to fundamentally re-think existing clinical practice in terms of ethical concerns and in terms of the reported experiences of intersex people.
Teenagers who plan parenthood
Authors: Quinlivan Julie A.
Published: November 2005

It is clear that a variable number of teenage mothers have, to some extent, planned parenthood. From an evolutionary perspective, it could be argued that teenage childbearing may in fact be a positive adaptive mechanism for humans raised in a hostile environment. Life history theory suggests that in risky and uncertain environments the optimal reproductive strategy is to reproduce early in order to maximise the probability of leaving any descendents at all. If some teenagers are planning or hoping for pregnancy, it is possible that some positive behavioural changes may be observed. This has proven to be the case with many teenagers altering their risk taking behaviours in the anticipation and expectation of pregnancy. There is now substantial evidence that teenagers who become pregnant were at higher risk than the general population for using cigarettes, alcohol, and marijuana. However, once pregnant, rates of consumption are usually lower compared with their non-pregnant peers or even their own personal pre-pregnancy rates of consumption. Therefore, for some teenagers, the conscious or unconscious prospect of pregnancy represents a potential space in which to rethink behaviours that may be harmful to themselves as a future mother, and also to their child. Given that teenage motherhood is not going to simply vanish, it is important to remember to focus research and services on validated interventions that may assist teenage mothers fulfill their ambitions of parenthood and simultaneously provide the best outcomes for their offspring. Evidence-based interventions focus on sustained home visitation by nurses, with limited evidence supporting the use of volunteers. In contrast, evidence suggests that home visitation by paraprofessionals may not be effective. Other strategies that may be helpful include the use of multidisciplinary teenage pregnancy clinics that have been noted to be associated with improved pregnancy outcomes. The role of new mothers’ groups, other community based group activities, peer support workers and intensive educational interventions to encourage return to schooling may be useful but have not been subjected to randomised evaluation. Such evaluation needs to occur.
A theoretical discussion of the impact of stigma on psychological adjustment to having a sexually transmissible infection
Authors: Newton Danielle C. , McCabe Marita P.
Published: November 2005

This paper provides a discussion of the utility of stigma theory as a conceptual framework for the interpretation and analysis of the psychological impact of contracting a sexually transmissible infection (STI). Most particularly, it focuses on those viral infections that cannot be medically cured, such as genital herpes and genital human papilloma virus. Recent research in the area of STIs suggests that the stigma associated with these conditions can hinder psychosocial and sexual adjustment post-diagnosis, and provides support for the use of stigma theory as a conceptual framework with which to analyse these experiences. This paper defines the concept of stigma and presents a theoretical overview of the process of stigmatisation. Three dimensions of stigma relevant to the experience of having a STI are then presented: the degree of concealability of the condition including the social consequences of concealing a condition; the origin of the condition; and the degree of peril presented by the condition. An overview of the way in which the presence of a stigmatising condition such as a STI may affect a person’s feelings of self and his/her intimate relationships is then presented. Finally, the implications of stigma theory as a conceptual framework for guiding future research in the area of personal and interpersonal reactions to STIs is discussed.
Hepatitis A and B infection and vaccination in a cohort of homosexual men in Sydney
Authors: Jin Fengyi , Prestage Garrett P. , Pell Catherine M. , Donovan Basil , Van de Ven Paul G. , Kippax Susan C. , Kaldor John M. , Grulich Andrew E.
Published: November 2005

Objectives: To determine the prevalence and incidence of hepatitis A (HAV) and B (HBV) infection and vaccination in HIV-negative homosexual men in Sydney, and associated risk factors. Methods: An open prospective cohort study was conducted among a community-based sample of HIV-negative homosexual men in Sydney in 2001–02. Participants underwent a face-to-face interview, regarding demographics, sexual behavioural risk factors and sexually transmitted infections, and blood samples were collected. They were followed annually. Results: Nine hundred and three men completed a baseline interview by the end of 2002. Among them, 68% were seropositive to hepatitis A. The seroprevalence of prior hepatitis B infection was 19%, and 53% had serological evidence of HBV vaccination. Younger men were much more likely to be seronegative, with 48% and 46% of <25-year-olds being seronegative to HAV and HBV respectively. In multivariate analysis HAV and HBV infection were associated with increasing age, greater number of lifetime sex partners and HBV infection was also associated with previous sexually transmitted infections. HAV vaccination was associated with increasing age, greater number of lifetime sex partners, overseas travel in the last year and self-reported anogenital warts. HBV vaccination was associated with higher occupational status, greater lifetime number of sex partners and previous sexually transmitted infections. Conclusion: Substantial proportions of gay community attached young homosexual men are still at risk of HAV and HBV infection. This study points to a need for vaccination strategies which ensure high levels of hepatitis A and B immunity in young sexually active gay men.
Genital Chlamydia trachomatis infection in Australia: epidemiology and clinical implications
Authors: Chen Marcus Y. , Donovan Basil
Published: November 2005

Over the last decade, notification rates for genital Chlamydia trachomatis infection in Australia have been rising progressively. While chlamydia is common and possibly increasing in the general population, heterosexual adolescents, indigenous Australians in remote settings, and homosexually active men are at particular risk of infection. Few studies are available on the extent of morbidity from chlamydia-associated diseases. Australia urgently needs a national strategy to control chlamydia, with widespread, selective screening as a key component. As general practitioners have an important role to play, we proffer guidelines for selective testing in primary care.
Use of a community sexual health information line
Authors: Knight Vickie , Hoskin Kristie , Tribe Kate
Published: November 2005

Background: Since 1989 Sydney Sexual Health Centre has provided a community phone information line (PIL). The service aims to educate and promote the sexual health of the community and facilitate efficient use of the centre’s resources through the provision of information and advice to the community and health professionals; a referral service; and patient triage. In October 1997 a comprehensive computerised database was developed to collect caller information. In 2003, a 5-year review of the PIL database was undertaken with the express aim of describing the profile of people using the service. Methods: We analysed data from the PIL from 16 October 1997 to end 20 December 2002 using SPSS. Results: A total of 34 013 callers were in the PIL database. Every year the service has seen an increase in demand from 5295 calls in 1998 (first full year of service) to 8401 in 2002. The majority of callers lived in central and southeast Sydney geographical area, however, calls were registered from over 55% of postcodes in NSW and from interstate. The average caller age each year was 32 years with similar standard deviation and the distribution over time has not changed. There were equal numbers of male and female callers each year. Peak times for people to call the PIL were 2–4 pm with a high number of callers at 10 am. In general, calls were between 4 and 6 Min duration. Overall, 14 098 (41.4%) of calls in the database were for general sexual health information. The majority of the information callers over the period who have been calling about infections have called about herpes simplex virus. Conclusions: As is evident the PIL meets a specific community need. This study did not, however, look at patient outcomes and this area needs investigation to fully evaluate the benefits of a community PIL.
Sexual exposure to blood and behavioural risks among STI clinic patients in Cape Town, South Africa
Authors: Kalichman Seth C. , Simbayi Leickness C.
Published: November 2005

Background: Exposure to blood during sexual intercourse is potentially important and yet understudied in HIV transmission. Methods: The study included 415 men and 127 women receiving diagnostic and treatment services at a sexually transmitted infections (STI) clinic in Cape Town, South Africa, who completed anonymous sexual health behaviour surveys. Results: More than 30% of both men and women reported engaging in sexual intercourse involving genital bleeding in the previous 3 months. Individuals who had engaged in sexual intercourse involving blood had significantly greater numbers of sex partners in the previous 3 months (OR = 1.6, 95%, CI = 1.1–2.3), engaged in higher rates of unprotected vaginal intercourse (OR = 1.2, 95%, CI = 1.1–1.2), were significantly more likely to have exchanged sex for money or materials (OR = 3.1, 95%, CI = 1.7–5.5) and were significantly more likely to have experienced condom breaks during intercourse (OR = 1.7, 95%, CI = 1.2–2.4). Conclusions: These findings suggest that exposure to blood during vaginal intercourse is prevalent among STI clinic patients in Cape Town and may be an important contributing factor to the rapid spread of HIV in South Africa.
Sexual health promotion in Thailand
Authors: Chandeying Verapol
Published: November 2005

Sexuality and power are at the root of most sexual and reproductive health problems in Thailand, including reproductive tract infections, fertility and population control, unwanted pregnancy and abortion, unsafe abortion, unsafe motherhood and violence against women, as well as issues emerging from the mobile and migrant population, including the spreading of HIV/AIDS. In the past three decades, reproductive health services in Thailand have been established and strengthened. Since 1995, reproductive health has become a priority of the Ministry of Public Health. Health system reform in 2000 led to strategies and actions of health performance improvement. Ongoing multisectoral programmes include: (1) political and social involvement; (2) training for professionals; (3) multidimensional services; and (4) research.
Antiretroviral-therapy-associated lipoatrophy: current status and future directions
Authors: Nolan David , Mallal Simon
Published: November 2005

Lipoatrophy is perhaps the most visibly recognisable component of antiretroviral-therapy-associated lipodystrophy due to the rarity of this form of body composition change in the general population. In this respect, it is apparent that lipoatrophy represents a form of drug toxicity specifically involving the subcutaneous fat tissue, resulting in pathological fat loss that preferentially affects the limbs and face. It is now clear that the choice and duration of nucleoside analogue reverse transcriptase inhibitor (NRTI) therapy (stavudine > zidovudine) is the dominant risk factor for clinical lipoatrophy, as well as for the pathological changes to adipose tissue that underlie the clinical syndrome. Host factors have also emerged as important modulators of lipoatrophy severity in patients receiving these NRTI drugs, including age, racial origin, and severity of immune deficiency. On the other hand, the use of selected HIV protease inhibitor drugs is more closely associated with metabolic complications such as dyslipidemia and insulin resistance and has not been convincingly linked to lipoatrophy. This review examines the clinical and pathological manifestations of lipoatrophy, and also presents information regarding the safety profile of alternative NRTI drugs, such as tenofovir and abacavir, that have not been associated with lipoatrophy risk. With increasing knowledge of lipoatrophy pathogenesis, it is likely that moderate and severe forms of this complication can now be considered a preventable complication of HIV treatment. However, it is also important to recognise that there is an ongoing burden of disease in patients who have been affected by lipoatrophy over the past six years, and that therapeutic management of established lipoatrophy will remain a challenge into the future.
Reconsidering HIV testing—consent is still the key
Authors: Bowden Francis J.
Published: November 2005

The high quality and easy accessibility of HIV testing in Australia has been one of the reasons for Australia’s effective response to the epidemic. However there have been a number of changes in the epidemiology of HIV and new technologies and treatments have emerged since the last Australian HIV policy was released in 1998. Antenatal testing to prevent vertical transmission, the licensing of rapid, point-of-care test kits in the United States and the problem of late diagnosis of infection in some populations are important issues to consider in the context of the drafting of a new HIV testing policy. The terms ‘pre- and post-test counselling’ are seen, by some, as barriers to HIV testing in the broader community. Reframing the process with a focus on the desired result (i.e. informed consent for voluntary testing) rather than on the process (i.e. pre-test counselling) could be one way to increase the rate of appropriate testing.
Personality predicts activity in reward and emotional regions associated with humor
Authors: Mobbs Dean , Hagan Cindy C. , Azim Eiman , Menon Vinod , Reiss Allan L.
Published: November 2005

Previous research and theory suggest that two stable personality dimensions, extroversion and neuroticism, differentially influence emotional reactivity to a variety of pleasurable phenomena. Here, we use event-related functional MRI to address the putative neural and behavioral associations between humor appreciation and the personality dimensions of introversion-extroversion and emotional stability-neuroticism. Our analysis showed extroversion to positively correlate with humor-driven blood oxygenation level-dependent signal in discrete regions of the right orbital frontal cortex, ventrolateral prefrontal cortex, and bilateral temporal cortices. Introversion correlated with increased activation in several regions, most prominently the bilateral amygdala. Although neuroticism did not positively correlate with any whole-brain activation, emotional stability (i.e., the inverse of neuroticism) correlated with increased activation in the mesocortical-mesolimbic reward circuitry encompassing the right orbital frontal cortex, caudate, and nucleus accumbens. Our findings tie together existing neurobiological studies of humor appreciation and are compatible with the notion that personality style plays a fundamental role in the neurobiological systems subserving humor appreciation.
Disruption of a
Plasmodium falciparum
gene linked to male sexual development causes early arrest in gametocytogenesis
Authors: Furuya Tetsuya , Mu Jianbing , Hayton Karen , Liu Anna , Duan Junhui , Nkrumah Louis , Joy Deirdre A. , Fidock David A. , Fujioka Hisashi , Vaidya Akhil B. , Wellems Thomas E. , Su Xin-zhuan
Published: November 2005

A male gametocyte defect in the
Plasmodium falciparum
Dd2 parasite was previously discovered through the observation that all progeny clones in a Dd2 × HB3 genetic cross were the result of fertilization events between Dd2 female and HB3 male gametes. A determinant linked to the defect in Dd2 was subsequently mapped to an 800-kb segment on chromosome 12. Here, we report further mapping of the determinant to an 82-kb region and the identification of a candidate gene,
P. falciparum
male development gene 1 (
pfmdv-1
), that is expressed at a lower level in Dd2 compared with the wild-type normal male gametocyte-producing ancestor W2. Pfmdv-1 protein is sexual-stage specific and is located on the gametocyte plasma membrane, parasitophorous vacuole membrane, and the membranes of cleft-like structures within the erythrocyte. Disruption of
pfmdv-1
results in a dramatic reduction in mature gametocytes, especially functional male gametocytes, with the majority of sexually committed parasites developmentally arrested at stage I. The
pfmdv-1
-knockout parasites show disturbed membrane structures, particularly multimembrane vesicles/tubes that likely derive from deformed cleft-like structures. Mosquito infectivity of the knockout parasites was also greatly reduced but not completely lost. The results suggest that
pfmdv-1
plays a key role in gametocyte membrane formation and integrity.