Structurally stabilized mesoporous TiO2 nanofibres for efficient dye-sensitized solar cells

One-dimensional (1D) TiO2 nanostructures are very desirable for providing fascinating properties and features, such as high electron mobility, quantum confinement effects, and high specific surface area. Herein, 1D mesoporous TiO2 nanofibres were prepared using the electrospinning method to verify their potential for use as the photoelectrode of dye-sensitized solar cells (DSSCs). The 1D mesoporous nanofibres, 300 nm in diameter and 10-20 μm in length, were aggregated from anatase nanoparticles 20-30 nm in size. The employment of these novel 1D mesoporous nanofibres significantly improved dye loading and light scattering of the DSSC photoanode, and resulted in conversion cell efficiency of 8.14%, corresponding to an ∼35% enhancement over the Degussa P25 reference photoanode.

Improved photovoltaic performance of dye-sensitized solar cells with modified self-assembling highly ordered mesoporous TiO 2 photoanodes

Strategies for improving the photovoltaic performance of dye-sensitized solar cells (DSSCs) are proposed by modifying highly transparent and highly ordered multilayer mesoporous TiO 2 photoanodes through nitrogen-doping and top-coating with a light-scattering layer. The mesoporous TiO 2 photoanodes were fabricated by an evaporation-induced self-assembly method. In regard to the modification methods, the light-scattering layer as a top-coating was proved to be superior to nitrogen-doping in enhancing not only the power conversion efficiency but also the fill factor of DSSCs. The optimized bifunctional photoanode consisted of a 30-layer mesoporous TiO 2 thin film (4.15 μm) and a Degussa P25 light-scattering top-layer (4 μm), which gives rise to a ∼200% higher cell efficiency than for unmodified cells and a fill factor of 0.72. These advantages are attributed to its higher dye adsorption, better light scattering, and faster photon-electron transport. Such a photoanode configuration provides an efficient way to enhance the energy conversion efficiency of DSSCs.

Rational design of 3D dendritic TiO2 nanostructures with favorable architectures

Controlling the morphology and size of titanium dioxide (TiO2) nanostructures is crucial to obtain superior photocatalytic, photovoltaic, and electrochemical properties. However, the synthetic techniques for preparing such structures, especially those with complex configurations, still remain a challenge because of the rapid hydrolysis of Ti-containing polymer precursors in aqueous solution. Herein, we report a completely novel approach-three- dimensional (3D) TiO2 nanostructures with favorable dendritic architectures-through a simple hydrothermal synthesis. The size of the 3D TiO2 dendrites and the morphology of the constituent nano-units, in the form of nanorods, nanoribbons, and nanowires, are controlled by adjusting the precursor hydrolysis rate and the surfactant aggregation. These novel configurations of TiO2 nanostructures possess higher surface area and superior electrochemical properties compared to nanoparticles with smooth surfaces. Our findings provide an effective solution for the synthesis of complex TiO2 nano-architectures, which can pave the way to further improve the energy storage and energy conversion efficiency of TiO 2-based devices.

Mapping the risk of soil-transmitted helminthic infections in the Philippines

Background In order to increase the efficient allocation of soil-transmitted helminth (STH) disease control resources in the Philippines, we aimed to describe for the first time the spatial variation in the prevalence of A. lumbricoides, T. trichiura and hookworm across the country, quantify the association between the physical environment and spatial variation of STH infection and develop predictive risk maps for each infection. Methodology/Principal Findings Data on STH infection from 35,573 individuals across the country were geolocated at the barangay level and included in the analysis. The analysis was stratified geographically in two major regions: 1) Luzon and the Visayas and 2) Mindanao. Bayesian geostatistical models of STH prevalence were developed, including age and sex of individuals and environmental variables (rainfall, land surface temperature and distance to inland water bodies) as predictors, and diagnostic uncertainty was incorporated. The role of environmental variables was different between regions of the Philippines. This analysis revealed that while A. lumbricoides and T. trichiura infections were widespread and highly endemic, hookworm infections were more circumscribed to smaller foci in the Visayas and Mindanao. Conclusions/Significance This analysis revealed significant spatial variation in STH infection prevalence within provinces of the Philippines. This suggests that a spatially targeted approach to STH interventions, including mass drug administration, is warranted. When financially possible, additional STH surveys should be prioritized to high-risk areas identified by our study in Luzon.

Transport-related fatalities and injuries leading to hospitalisation in pre-school children

Pre-school children grow and develop rapidly with age and their changing capabilities are reflected in the ways in which they are injured. Using coded and textual descriptions of transport-related injuries in children under five years of age from the Queensland Injury Surveillance Unit (QISU) this paper profiles the modes of such injuries by single year of age. The QISU collects information on all injury presentations to emergency department in hospitals throughout Queensland using both coded information and textual description. Almost all transport-related injuries in children under one year are due to motor vehicle crashes but these become proportionately less common thereafter, while injuries while cycling become proportionately more common with age. Slow-speed vehicle runovers peak at age one year but occur at all ages in the range. Bicycle-related fatalities are rare in this age group. If bicycle-related injuries are excluded, the profiles of fatal and non-fatal injuries are broadly similar. Comparison with a Queensland hospital series suggests that these results are broadly representative.

Death, Ancestors, and HIV/AIDS among the Akan of Ghana

This is a study of crises caused by HIV/AIDS among the Akan of Ghana. It creates more awareness about the epidemic and has indicated other possible paths for campaign strategies. The pandemic has many devastating consequences; yet new infections are recorded daily despite campaigns against the disease. The search for therapy often sees the use of multiple outlets, which expresses Ghana's pluralistic medical system based on Kleinman's sector analytical model involving Western medicine, self-therapy, and folk healing. But it also leaves individuals and kin members in financial quandary. The fieldwork for this study is mainly through participant observation lasting 13 months (February 2003 to March 2004) among the Akan; in addition, some archival materials have been used. The Akan people live in the coastal south and forest zone of Ghana. Every Akan village or town is made up of corporate lineages, and social organisation is based on matrilineal descent. The society is holistic because the matrilineages seek the welfare of all their members. Meyer Fortes, R. S. Rattray and others on the Akan noticed this encompassing nature in the lineage organisation; but they did not make it salient (or failed to notice it) during illness, efforts for healing, and the care of the sick member. HIV/AIDS is an illness which shows the encompassing nature of the Akan matrilineage. It also reveals many contradictions in the group, viz. stigmatisation, abandonment, and attitudes that do not express altruism in a group expected to be closely-knit based on members' belief that they are of the 'same blood'. The crises have been analyzed in the total social system because the disease creates breaches at various levels of social interaction. An analysis of crises in a group is not far-fetched; Victor Turner has shown the way among the Ndembu and has revealed the contraditions in the seemingly uneventful life in the group. This study has identified that in dealing with HIV/AIDS patients and crises about the disease we are dealing with 'holistic' patients. Their cases produce many changes in the matrilineal structure--many orphans are being created and the care of patients is increasingly falling on the elderly. HIV/AIDS also challenges Akan cosmology because, for example, an AIDS death in local notions is a 'bad' demise which fails to produce ancestors who reproduce the society through reincarnation. Campaigns could emphasize this notion. The study begins with a description of the holistic nature of Akan matriliny, and the patients have been described as 'holistic' because their crises affect other people in the holistic society. Chapter 2 discusses the importance of ancestors as the starting points for social order who are constantly revered (in rites invoving the chief, Chapter 4). Chapter 3 focuses on funerals as an important social performance for the welfare of the dead and the living. Chapter 5 concentrates on HIV/AIDS as an illness threat marked by dominant discourses such as poverty, sexuality, migration, and condom use. Chapter 6 analyzes the attempts for therapy, and traditional healers' claims to have a cure. The efforts for therapy continues with spiritual church healing in Chapter 7, and chapter 8 is devoted to care of the patients and its inherent crises. Chapter 9 analyzes the effects of HIV/AIDS afflictions and AIDS deaths on the matrilineal group and in society. The study ends with a short part, devoted to Recommendations based on the findings in this investigation.

Trial of the Primary Care Practice Improvement Tool: Building organisational performance in Australian general practice and primary health care

Objective: To nationally trial the Primary Care Practice Improvement Tool (PC-PIT), an organisational performance improvement tool previously co-created with Australian primary care practices to increase their focus on relevant quality improvement (QI) activities. Design: The study was conducted from March to December 2015 with volunteer general practices from a range of Australian primary care settings. We used a mixed-methods approach in two parts. Part 1 involved staff in Australian primary care practices assessing how they perceived their practice met (or did not meet) each of the 13 PC-PIT elements of high-performing practices, using a 1–5 Likert scale. In Part 2, two external raters conducted an independent practice visit to independently and objectively assess the subjective practice assessment from Part 1 against objective indicators for the 13 elements, using the same 1–5 Likert scale. Concordance between the raters was determined by comparing their ratings. In-depth interviews conducted during the independent practice visits explored practice managers’ experiences and perceived support and resource needs to undertake organisational improvement in practice. Results: Data were available for 34 general practices participating in Part 1. For Part 2, independent practice visits and the inter-rater comparison were conducted for a purposeful sample of 19 of the 34 practices. Overall concordance between the two raters for each of the assessed elements was excellent. Three practice types across a continuum of higher- to lower-scoring practices were identified, with each using the PC-PIT in a unique way. During the in-depth interviews, practice managers identified benefits of having additional QI tools that relate to the PC-PIT elements. Conclusions: The PC-PIT is an organisational performance tool that is acceptable, valid and relevant to our range of partners and the end users (general practices). Work is continuing with our partners and end users to embed the PC-PIT in existing organisational improvement programs.

Lewis Acid-Lewis Base Mediated Metal-Free Hydrogen Activation and Catalytic Hydrogenation

Organocatalysis, the use of organic molecules as catalysts, is attracting increasing attention as one of the most modern and rapidly growing areas of organic chemistry, with countless research groups in both academia and the pharmaceutical industry around the world working on this subject. The literature review of this thesis mainly focuses on metal-free systems for hydrogen activation and organocatalytic reduction. Since these research topics are relatively new, the literature review also highlights the basic principles of the use of Lewis acid-Lewis base pairs, which do not react irreversibly with each other, as a trap for small molecules. The experimental section progresses from the first observation of the facile heterolytical cleavage of hydrogen gas by amines and B(C6F5)3 to highly active non-metal catalysts for both enantioselective and racemic hydrogenation of unsaturated nitrogen-containing compounds. Moreover, detailed studies of structure-reactivity relationships of these systems by X-ray, neutron diffraction, NMR methods and quantum chemical calculations were performed to gain further insight into the mechanism of hydrogen activation and hydrogenation by boron-nitrogen compounds.

Tyttöjen oma tila. Somalialaistaustaisten nuorten draamaprojekti Helsingissä monikulttuurisen lapsuuden näkökulmasta.

Pro Gradu tarkastelee somalialaistaustaisista tytöstä muodostuneen draamaryhmän harjoitusprosessia ja esitystä antropologisen teatteri- ja esitystutkimuksen valossa. Tutkimuskohteena on Kassandara ry:n järjestämä monikulttuurinen tyttöjen draamatoiminta helsinkiläisen lähiön asukastilalla. Tutkimuksen aiheena ovat draamaprosessin sosiaaliset merkitykset sekä draaman tarinan merkitys monikulttuurisen lapsuuden näkökulmasta. Aineisto koostuu osallistuvasta havainnoinnista ja teemahaastatteluista. Työ analysoi draamaprosessin sosiaalisia ja yhteisöllisiä merkityksiä. Aineistoa tarkastellaan sukupuolisen segregaation sekä toimijuuden ja sen mahdollistumisen näkökulmista. Toimijuutta lähestytään Victor Turnerin liminaalisuus -käsitteen avulla sekä liminoidisena toimintana, joka mahdollistaa kapmoinnin ja kulttuuristen vaihtoehtojen tutkimisen. Draamakerho määritellään tyttöjen omaksi fyysiseksi ja ajalliseksi tilaksi. Näkökulmaa laajennetaan tytöistä heidän äiteihinsä, joita käsitellään vanhempina ja esityksen katsojina. Lisäksi analyysi kohdentuu teatteriesitykseen liittyviin lisärakenteisiin, kuten haijoitusjaksoon, esitykseen valmistautumiseen ja esityksen jälkeiseen tapahtumaan, josta aineistossa muodostui äitien ja tyttärien yhteinen juhla. Työssä tutkitaan myös draamaryhmän luoman fiktiivisen tarinan merkityksiä monikulttuurisen lapsuuden näkökulmasta. Tutkimus tarkastelee draaman ja sen tekijöiden kokemusmaailman suhdetta. Teatteri käyttää todellista elämää raakamateriaalinaan ja päinvastoin. Tutkimus lähestyy teatteria tilana, jossa todellisuuden ilmiöitä tai ongelmia voidaan tutkia ja tarkastella turvallisesti fiktion suojassa. Richard Schechnerin käsite käyttäytymisen toisinto kuvaa olemassa olevaa käytöstä, joka toimii mallina esitystilanteessa. Turnerin ja Schechner ovat yhdessä hahmotelleet ajatusta sosiaalisen elämän toimintojen käyttämisestä raakamateriaalina esteettisen draaman luomisessa. Tulkintakehyksenä sovelletaan Jean Rouchin antropologisen elokuvan etnofiktio -menetelmän lähestymistapaa. Etnofiktiossa tutkittavat henkilöt improvisoivat kameralle kohtauksia vastaavia ryhmiä edustavien fiktiivisten päähenkilöiden elämistä. Keskusteluun liitetään Johannes Sjöberg ajatuksia etnofiktion-menetelmän mahdollisuuksista tarkastella ongelmia ja niiden ratkaisuhorisontteja. Monikulttuuriset nuoret ovat usein ikä- ja kansalaisuuskategorioiden välimaastossa, jolloin taustatekijöillä sekä kontekstilla on erityinen merkitys toimijuudelle ja sen mahdollistumiselle. Toiminta kiinnittyy ennen kaikkea ihmissuhteiden verkkoon. Teatteri ja sen lisärakenteet vahvistavat tekijöidensä sekä katsojiensa sosiaalisuutta kuin myös yhteisöllisyyttä. Tyttöjen transkulttuurinen lapsuus heijastui tarinaan, johon materiaalia kumpusi kolmesta osittain keskenään sekoittuneesta alueesta: koti, kouluja elokuvallinen haavetodellisuus. Tutkimus vahvisti ajatusta, että draamaa tehdessään ihmiset käyttävät arkielämän kokemusmaailmaansa raakamateriaalinaan Teatteriesityksillä on erityistä merkitystä kulttuurin ilmaisijoina. Teatteri kehystää ja kontrolloi ihmisten vuorovaikutuksen ongelmallisimpia tilanteita. Draaman avulla kerrotaan omien ja muiden kokemuksiin pohjautuvia tarinoita, joiden kautta yritetään ymmärtää ympäröivää maailmaa.

Raman study of pressure-induced structural transitions in CsIO4 to 12 GPa

High pressure Raman scattering studies have been carried out on cesium periodate (CsIO4) using the diamond anvil cell. Three pressure-induced phase transitions occur in the range 0.1�12 GPa as indicated by abrupt changes in the Raman spectra, and pressure dependence of the phonon frequencies. The transitions are observed at 1.5, 4.5 and 6.2 GPa in the increasing pressure cycle. A large hysteresis is noticed for the reverse transition when releasing the pressure. The high pressure phase is nearly quenchable to ambient pressure. The nature of the pressure-induced transitions are discussed in terms of the sequence of pressure-induced transitions expected for scheelite-pseudoscheelite structure ABO4 compounds from crystal chemical considerations. For the softening of the two high frequency internal modes, a pressure-induced electronic change involving the 5 d states of cesium and 5 p states of iodine is invoked.

ac transport studies of La-modified antiferroelectric lead zirconate thin films

In recent times antiferroelectric thin-film material compositions have been identified as one of the most significant thin films for development of devices such as high charge storage, charge couplers/decouplers, and high strain microelectromechanical systems. Thus, understanding the dielectric and electrical properties under an ac signal drive in these antiferroelectric thin-film compositions, such as lead zirconate thin films, and the effect of donor doping on them is very necessary. For this purpose, thin films of antiferroelectric lead zirconate and La-modified lead zirconate thin films with mole % concentrations of 0, 3, 5, and 9 have been deposited by pulsed excimer laser ablation. The dielectric and hysteresis properties have confirmed that with a gradual increase of the La content, the room-temperature antiferroelectric lead zirconate thin films can be modified into ferroelectric and paraelectric phases. ac electrical studies revealed that the polaronic related hopping conduction is responsible for the charge transport phenomenon in these films. With a La content of less than or equal to3 mole % in pure lead zirconate, the conductivity of the films has been reduced and followed by an increase of its conductivity for a greater than or equal to3% addition of La to lead zirconate thin films. The polaronic activation energies are also found to follow a similar trend as that of the conductivity.

Alternating current conduction and impedance spectroscopy analysis on pulsed excimer laser ablated (Pb, La)TiO3 thin films

Lanthanum doped lead titanate (PLT) thin films were identified as the most potential candidates for the pyroelectric and memory applications. PLT thin films were deposited on Pt coated Si by excimer laser ablation technique. The polarization behavior of PLT thin films has been studied over a temperature range of 300 K to 550 K. A universal power law relation was brought into picture to explain the frequency dependence of ac conductivity. At higher frequency region ac conductivity of PLT thin films become temperature independent. The temperature dependence of ac conductivity and the relaxation time is analyzed in detail. The activation energy obtained from the ac conductivity was attributed to the shallow trap controlled space charge conduction in the bulk of the sample. The impedance analysis for PLT thin films were also performed to get insight of the microscopic parameters, like grain, grain boundary, and film-electrode interface etc. The imaginary component of impedance Z" exhibited different peak maxima at different temperatures. Different types of mechanisms were analyzed in detail to explain the dielectric relaxation behavior in the PLT thin films.

Study of relaxor behavior of 0.7Pb(Mg1/3Nb2/3)O-3-0.3PbTiO(3) thin films

Relaxor properties of polycrystalline 0.7Pb(Mg1/3Nb2/3)O-3-0.3PbTiO(3) (PMN-PT) thin films were studied in terms of the diffuse nature of phase transition along with the frequency dispersion of temperature (T-m) at which the dielectric constant exhibits maximum value. Existence of remnant polarization (P-r) above the phase transition temperature, which is a characteristic property of typical relaxor ferroelectric has also been observed in the present case. The films exhibited a gradual decrease of remnant polarization with increase of temperature. Among the different models of relaxor ferroelectric, Vogel-Fulcher model has been found to be suitable to describe the frequency dispersion of T-m in this case. Freezing of dipole moment with decrease of temperature was thought to be the origin of the temperature dependence of dielectric dispersion.

Study of thickness dependence on electrical properties of (Pb,La)TiO3 thin films for memory applications

Lead-lanthanum-titanate (Pb0.72La0.28)TiO3 (PLT) is one of the interesting materials for DRAM applications due to its room temperature paraelectric nature and its higher dielectric permittivity. PLT thin films of different thickness ranging from 0.54- 0.9 mum were deposited on Pt coated Si substrates by excimer laser ablation technique. We have measured the voltage (field) dependence, the thickness dependence, temperature dependence of dc leakage currents and analysis is done on these PLT thin films. Current- voltage characteristics were measured at different temperatures for different thick films and the thickness dependence of leakage current has been explained by considering space charge limited conduction mechanism. The charge transport phenomena were studied in detail for films of different thicknesses for dynamic random access memory applications.

The thickness dependence of the electrical and dielectric properties in the laser ablated SrBi2Nb2O9 thin films

he thickness dependence of the electrical properties in the thin films of uniaxial SrBi2Nb2O9 has been studied in this report. According to many published literatures, it could be an effective way to identify the basic conduction process. The laser ablation was chosen as the deposition technique to ensure an oriented growth and a proper stoichiometric deposition. The structural, dielectric and conduction properties were studied as a function of thickness. The films showed good ferroelectric properties, an ordered growth, and a space-charge controlled conduction process, which was double checked by reversing the polarity of the applied voltage, and also by examining the high field current response of the sample varying in thickness.