bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous mixing and pumping using asymmetric microelectrodes
Authors: Kim Byoung Jae , Yoon Sang Youl , Sung Hyung Jin , Smith Charles G.
Published: October 2007

This study proposes ideas for simultaneous mixing and pumping using asymmetric microelectrode arrays. The driving force of the mixing and pumping was based on electroosmotic flows induced by alternating current (ac) electric fields on asymmetric microelectrodes. The key idea was to bend/incline the microelectrodes like diagonal/herringbone shapes. Four patterns of the asymmetric electrode arrays were considered depending on the shape of electrode arrays. For the diagonal shape, repeated and staggered patterns of the electrode arrays were studied. For the herringbone shape, diverging and converging patterns were examined. These microelectrode patterns forced fluid flows in the lateral direction leading to mixing and in the channel direction leading to pumping. Three-dimensional numerical simulations were carried out using the linear theories of ac electro-osmosis. The performances of the mixing and pumping were assessed in terms of the mixing efficiency and the pumping flow rate. The results indicated that the helical flow motions induced by the electrode arrays play a significant role in the mixing enhancement. The pumping performance was influenced by the slip velocity at the center region of the channel compared to that near the side walls.
Effects of grain size on the dielectric properties of Pb(Mg1/3Nb2/3)O3-30 mol % PbTiO3 ceramics
Authors: Jo Wook , Kim Tae-Hyeong , Kim Doh-Yeon , Pabi Shyamal Kumar
Published: October 2007

The effects of the average grain size on the phase transformation and consequent changes in the dielectric properties of Pb(Mg1/3Nb2/3)O3-30 mol % PbTiO3 were investigated. It was observed that the size refinement down to ∼90 nm impeded the phase transformation of the cubic phase formed in the course of sintering either into rhombohedral or into tetragonal one, and a series of phase transformation from cubic to rhombohedral and then to tetragonal phase took place as the average grain size increased from ∼90 nm to ∼5.7 μm. This dependence of the crystal structure on the grain size was qualitatively explained in terms of the capillarity effect and the free volume at the grain boundaries exerting a negative hydrostatic pressure on the grains. With the change in crystal structure the typical ferroelectric behavior in dielectric properties evolved into that of a relaxor and finally into a paraelectric one. The overall changes in the dielectric behavior were interpreted on the basis of the size-driven phase transformation. An anomalous dielectric behavior, i.e., a relatively high dielectric constant over a wide range of temperature (30–330 °C), was observed at the average grain size of ∼330 nm possibly due to a state of a single domain in a single grain, while below ∼90 nm all the phases in the system practically transformed into the paraelectric cubic phase.
Dynamics of spin-dependent tunneling through a semiconductor double-barrier structure
Authors: Gong J. , Liang X. X. , Ban S. L.
Published: October 2007

The dynamics of spin-dependent tunneling through a nonmagnetic semiconductor double-barrier structure is studied including the k3 Dresselhaus spin orbit coupling is solved by the time-dependent Schrödinger equation with a developed method for the finite-difference relaxation. The resonant peak and quasibound level lifetime are determined by the in-plane wave vector and the applied electric field. The buildup time and decay lifetime of resonant probability amplitude are different for the spin-down and spin-up electrons due to the Dresselhaus spin-orbit coupling. Further investigation shows that the steady spin-polarization in both the well and collector regions has been obtained in the time domain.
Thermal radiation in dense nano- and microparticulate media
Authors: Prasher Ravi
Published: October 2007

Thermal radiation transport in dense nano/microparticulate media is considered. The particulates are both scattering and absorbing. Effective field approximation and quasicrystalline approximation are used to obtain the dispersion relation for electromagnetic wave in nano/microparticulate media. Nano/microparticles are considered due to their promise for future applications such as nanofluids and also for current technologies such as fluidized and packed beds combustors. Due to multiple and dependent scattering, the density of states, phase velocity, and group velocity of photons are modified. Modification of these parameters modifies the Planck blackbody equilibrium emissive power. Results show that heat flux and temperature predictions made by models in the literature for multiple and dependent scattering and absorption are not very accurate, as these models do not take the modification of equilibrium emissive power into account.
In situ measurement of humidity induced changes in the refractive index and thickness of polyethylene glycol thin films
Authors: Bilen Bukem , Skarlatos Yani , Aktas Gulen , Inci Mehmet Naci , Dispinar Tugba , Kose Meliha Merve , Sanyal Amitav
Published: October 2007

Humidity induced changes in the refractive index and thickness of polyethylene glycol (PEG) thin films are in situ determined by optical waveguide spectroscopy. PEG brushes are covalently attached to the surface of a thin gold film on a borosilicate crown glass using a grafting-from chemical synthesis technique. The measurements are carried out in an attenuated total internal reflection setup. At low humidity levels, both the refractive index and the thickness change gradually due to swelling of the PEG thin films upon water intake. At around 80% relative humidity, a steep decrease in the refractive index and a steep increase in the thickness are observed as a result of a phase change from a semicrystalline state to a physical gel state. The hydrogenation of PEG films causes a less pronounced phase change from a semicrystalline state to a gel state. Due to fewer ether oxygen atoms available for the water molecules to make hydrogen bonding, the polymer has a more stable structure than before and the phase change is observed to shift to higher humidity levels. It is discussed that such a humidity induced change in the index of refraction can be utilized in constructing a PEG based humidity sensor.
Magnetic and magnetoelastic properties of Cr-substituted cobalt ferrite
Authors: Lee S. J. , Lo C. C. H. , Matlage P. N. , Song S. H. , Melikhov Y. , Snyder J. E. , Jiles D. C.
Published: October 2007

We have investigated the magnetic and magnetoelastic properties of a series of Cr-substituted cobalt ferrite CoCrxFe2−xO4 (x=0.0–0.79) samples. Substitution of Cr for some of the Fe in cobalt ferrite reduced the Curie temperature, and the effect is more pronounced than that observed in Mn-substituted cobalt ferrite samples. Cr substitution also caused the maximum magnetostriction to decrease at a greater rate than substitution of the same amount of Mn. The maximum of the strain derivative, dλ∕dH, was reached for x=0.38. The behavior of the Curie temperature of Cr-substituted and Mn-substituted cobalt ferrites has been analyzed using the Néel molecular field model and compared with recent Mössbauer spectroscopy results.
Photochromism in yttrium hydride
Authors: Ohmura Ayako , Machida Akihiko , Watanuki Tetsu , Aoki Katsutoshi , Nakano Satoshi , Takemura K.
Published: October 2007

Transparent orange yttrium hydride turns to black when illuminated by visible laser light at pressures of several gigapascals at room temperature. The marked reduction in optical transmittance extends over the infrared region, suggesting that illumination creates persistent free carriers. The opaque black sample returns to the transparent orange hydride during room-temperature annealing for a few hours. Photochromism is pronounced for the coexistent state of the metallic fcc-YH2 and the insulating hexagonal-YH3 state but is depressed for the single phase of hexagonal-YH3. The results indicate that light illumination can modify the optical and possibly electronic properties during a certain period of times.
Crystal orientation by unpolarized infrared reflectivity application to aluminum nitride
Authors: Kazan M.
Published: October 2007

We report on the application of Fourier transform infrared (FTIR) reflectivity as an approach to nondestructive optical technique for crystal orientation. Unpolarized FTIR reflectivity experiments were performed at near normal incidence on several facets of self-nucleated wurtzite aluminum nitride (AlN). The FTIR reflectivity spectra were carefully analyzed using the Kramers-Kronig technique. The orientation-dependent infrared reflectivity was described by a model which considers the infrared total response as being the combination of individual components of the reflected electric field. The AlN infrared active quasimodes were described by Loudon equations previously introduced for Raman active quasimodes in anisotropic materials.
An advanced molecule-surface scattering instrument for study of vibrational energy transfer in gas-solid collisions
Authors: Ran Qin , Matsiev Daniel , Wodtke Alec M. , Auerbach Daniel J.
Published: October 2007

We describe an advanced and highly sensitive instrument for quantum state-resolved molecule-surface energy transfer studies under ultrahigh vacuum (UHV) conditions. The apparatus includes a beam source chamber, two differential pumping chambers, and a UHV chamber for surface preparation, surface characterization, and molecular beam scattering. Pulsed and collimated supersonic molecular beams are generated by expanding target molecule mixtures through a home-built pulsed nozzle, and excited quantum state-selected molecules were prepared via tunable, narrow-band laser overtone pumping. Detection systems have been designed to measure specific vibrational-rotational state, time-of-flight, angular and velocity distributions of molecular beams coming to and scattered off the surface. Facilities are provided to clean and characterize the surface under UHV conditions. Initial experiments on the scattering of HCl(v=0) from Au(111) show many advantages of this new instrument for fundamental studies of the energy transfer at the gas-surface interface.
Slow flows of a vapor-gas mixture with large density and temperature variations in the near-continuum regime
Authors: Laneryd Carl-Johan Tor , Aoki Kazuo , Takata Shigeru
Published: October 2007

A binary mixture of a vapor and a noncondensable gas in contact with the boundary made of the condensed phase (liquid or solid) of the vapor is considered in the following situation: the amount of the noncondensable gas contained in the system is of the same order of magnitude as that of the vapor; the temperature variation along the boundary may be large; the boundary is at rest, and there is no flow at infinity when an infinite domain is considered; and the Knudsen number is small (i.e., near-continuum regime). Slow steady flows (with Mach number of the order of Knudsen number, or equivalently, with Reynolds number of the order of unity) of the mixture, mainly caused by evaporation and condensation of the vapor on the boundary, are investigated on the basis of kinetic theory. The basic system used in this work is the fluid-dynamic-type system that was derived systematically from the Boltzmann system in a previous paper [S. Takata and K. Aoki, Transp. Theor. Stat. Phys. 30, 205 (2001); erratum, Transp. Theor. Stat. Phys. 31, 289 (2002)] in connection with the ghost effect, and it is solved numerically by a finite-volume method. Some additional computation using the direct simulation Monte Carlo method, based on the original Boltzmann system, is also performed for comparison. The behavior of the mixture in the continuum limit in which the Knudsen number vanishes is discussed with special interest in the ghost effect.
Photoinduced two-dimensional gratings based on dye-doped cholesteric liquid crystal films
Authors: Yeh Hui-Chen , Chen Guang-Hao , Lee Chia-Rong , Mo Ting-Shan
Published: October 2007

This work elucidates photoinduced two-dimensional (2D) gratings in dye-doped cholesteric liquid crystal films. The helical pitch is increased by green-beam-induced trans-cis isomerization and a concomitant thermal effect. Two-dimensional gratings appear when the green beam is turned off. Grating formation results from elastic instability caused by restored strain arising from helical pitch reduction. Grating lifetime increases as green beam intensity increases and declines under irradiation with a strong red beam. Variation in grating spacing with green intensity with various pitches is also examined.
Dielectric properties of dysprosium- and scandium-doped hafnium dioxide thin films
Authors: Adelmann C. , Sriramkumar V. , Van Elshocht S. , Lehnen P. , Conard T. , De Gendt S.
Published: October 2007

Dysprosium- and scandium-doped HfO2 films have been deposited by atomic-vapor deposition on SiO2∕Si substrates. Glancing-incidence x-ray diffraction demonstrates that Dy0.10Hf0.90Ox and Sc0.10Hf0.90Ox films show a cubic crystal structure, whereas HfO2 films are monoclinic. The dielectric permittivity increases strongly from 16 for HfO2 to 32 for Dy0.10Hf0.90Ox and Sc0.10Hf0.90Ox. This leads to a reduction of the leakage current in the tunneling regime by up to three orders of magnitude for constant effective oxide thickness. For thick films (≳6nm), it is shown that leakage occurs via the Poole-Frenkel mechanism and that doping HfO2 increases leakage for constant physical oxide thickness.
Sm
Co
5
∕
Fe
nanocomposites synthesized from reductive annealing of oxide nanoparticles
Authors: Hou Yanglong , Sun Shouheng , Rong Chuanbing , Liu J. Ping
Published: October 2007

Hard magnetic nanocomposites SmCo5∕Fex (x=0–2.9) are synthesized by a simultaneous calcium reduction of Sm–Co–O and Fe3O4 nanoparticles. The composites consist of nanostructured SmCo5 and Fe with their average grain sizes at 29 and 8nm, respectively. The magnetic properties of the composites can be tuned by controlling Fe composition. SmCo5∕Fe1.5 shows an enhanced remanent magnetization at 56emu∕g (45emu∕g for SmCo5). The largest coercivity value of 11.6kOe is achieved with SmCo5∕Fe0.23. The synthesis represents a general process toward SmCo-based exchange-spring nanocomposites for high performance permanent magnet applications.
Possible efficient p-type doping of AlN using Be: An ab initio study
Authors: Wu R. Q. , Shen L. , Yang M. , Sha Z. D. , Cai Y. Q. , Feng Y. P. , Huang Z. G. , Wu Q. Y.
Published: October 2007

Spin density functional theory based ab initio study is carried out to investigate the feasibility of fabricating p-type AlN using Be as an efficient dopant. It is found that substitutional BeAl is an acceptor with an activation energy of 0.34eV. To overcome the low solubility of direct incorporation of Be into AlN and self-compensation from Be interstitials, we propose a hydrogen-assisted growth scheme which improves the solubility and suppresses interstitials. Oxygen is also found to be an effective codopant to activate Be in AlN. Our results suggest the possibility of improving p-type conductivity of AlN by Be doping.
5
-
nm
-thick TaSiC amorphous films stable up to 750°C as a diffusion barrier for copper metallization
Authors: Lin Ting-Yi , Cheng Huai-Yu , Chin Tsung-Shune , Chiu Chin-Fu , Fang Jau-Shiung
Published: October 2007

Ultrathin TaSiC amorphous films prepared by magnetron cosputtering using TaSi2 and C targets on Si(100), in a sandwiched scheme Si(100)∕TaSiC(5nm)∕Cu, were evaluated for barrier performance in copper metallization. Optimizing carbon content maximizes thermal stability of the films as depicted by sheet-resistance, x-ray diffraction, and transmission electron microscopy examination. The stability temperatures of 700°C (24at.% C) and 750°C (34at.% C) have been systematically verified and discussed. Since Ta, Si, and C are compatible with integrated circuit (IC) processing, the TaSiC films are readily applicable for sub-65-nm IC production.
High efficiency double heterojunction polymer photovoltaic cells using highly ordered TiO2 nanotube arrays
Authors: Mor Gopal K. , Shankar Karthik , Paulose Maggie , Varghese Oomman K. , Grimes Craig A.
Published: October 2007

Vertically oriented TiO2 nanotube arrays formed by anodization offer a highly ordered material architecture for efficient charge generation and collection in photoelectrochemical devices. A blend of regioregular poly(3-hexylthiophene) and a methanofullerene (phenyl C71-butyric acid methyl ester) was infiltrated into transparent TiO2 nanotube films. The heterojunction poly(3-hexylthiophene) (P3HT)-([6,6]-phenyl-C71-butyric acid methyl ester) and P3HT-TiO2 interfaces both result in charge separation. The resulting solid state solar cells show a short-circuit current density of 12.4mA∕cm2, 641mV open circuit potential, and a 0.51 fill factor, yielding power conversion efficiencies of 4.1% under AM 1.5 sun.
Slow relaxation of piezoelectric response in CdZnTe ferroelectric semiconductor single crystals
Authors: Ke Shanming , Huang Haitao , Wang Tao , Fan Huiqing , Jie Waiqi , Chan H. L. W.
Published: October 2007

The piezoelectric response in Cd0.9Zn0.1Te (CZT) semiconductor single crystals has been investigated by analyzing room temperature impedance spectra. The polarization is significantly influenced by light illumination. A slow relaxation process of the piezoelectric response has been observed with a relaxation time of 37s, which is comparable to the discharge current results. The frequencies for piezoelectric resonance and antiresonance can be tuned to lower values when a bias field is applied and can be recovered when the bias field is removed. These phenomena may be universal for ferroelectric semiconductors and can be explained by a slow relaxation model in dielectrics.
Humidity-dependent stability of amorphous germanium nitrides fabricated by plasma nitridation
Authors: Kutsuki Katsuhiro , Okamoto Gaku , Hosoi Takuji , Shimura Takayoshi , Watanabe Heiji
Published: October 2007

We have investigated the stability of amorphous germanium nitride (Ge3N4) layers formed by plasma nitridation of Ge(100) surfaces using x-ray photoelectron spectroscopy and atomic force microscopy. We have found that humidity in the air accelerates the degradation of Ge3N4 layers and that under 80% humidity condition, most of the Ge–N bonds convert to Ge–O bonds, producing a uniform GeO2 layer, within 12h even at room temperature. After this conversion of nitrides to oxides, the surface roughness drastically increased by forming GeO2 islands on the surfaces. These findings indicate that although Ge3N4 layers have superior thermal stability compared to the GeO2 layers, Ge3N4 reacts readily with hydroxyl groups and it is therefore essential to take the best care of the moisture in the fabrication of Ge-based devices with Ge3N4 insulator or passivation layers.
Quantum key distribution using a triggered quantum dot source emitting near 1.3μm
Authors: Intallura P. M. , Ward M. B. , Karimov O. Z. , Yuan Z. L. , See P. , Shields A. J. , Atkinson P. , Ritchie D. A.
Published: October 2007

We report the distribution of a cryptographic key, secure from photon number splitting attacks, over 35km of optical fiber using single photons from an InAs quantum dot emitting ∼1.3μm in a pillar microcavity. Using below GaAs-bandgap optical excitation, we demonstrate suppression of multiphoton emission to 10% of the Poissonian level without detector dark count subtraction. The source is incorporated into a phase encoded interferometric scheme implementing the BB84 protocol for key distribution over standard telecommunication optical fiber. We show a transmission distance advantage over that possible with (length-optimized) uniform intensity weak coherent pulses at 1310nm in the same system.
Finding the Political ‘Sweet Spot’: Sectional Interests, Consensus Power, and the Everglades Restudy (1992–2000)
Authors: Dengler Mary
Published: October 2007

Collaborative decision making and management frequently encompass a diverse range of scenarios. The author explores a specific mechanism of collaboration: the inclusion of competing sectional interests in an ad hoc organization with consensus governance rules to influence an ongoing planning process. Drawing from an empirical study of the Everglades Restudy process (1992–2000), the author analyzes how and why the Governor's Commission for a Sustainable South Florida offered planners and US Congress the sociopolitically acceptable conceptual framing for a multipurpose water management plan. Inclusion of legitimate representatives from powerful sectional interests, consensus governance rules, and time for building social capital were qualities that positioned the organization to assume an influential role in the governance regime of the planning process.
Drosophila
follicle cell amplicons as models for metazoan DNA replication: A
cyclinE
mutant exhibits increased replication fork elongation
Authors: Park Eugenia A. , MacAlpine David M. , Orr-Weaver Terry L.
Published: October 2007

Gene clusters amplified in the ovarian follicle cells of
Drosophila
serve as powerful models for metazoan DNA replication. In response to developmental signals, specific genomic regions undergo amplification by repeated firing of replication origins and bidirectional movement of replication forks for ≈50 kb in each direction. Previous work focused on initiation of amplification, defining replication origins, establishing the role of the prereplication complex and origin recognition complex (ORC), and uncovering regulatory functions for the Myb, E2F1, and Rb transcription factors. Here, we exploit follicle cell amplification to investigate the control of DNA replication fork progression and termination, poorly understood processes in metazoans. We identified a mutant in which, during gene amplification, the replication forks move twice as far from the origin compared with wild type. This phenotype is the result of an amino acid substitution mutation in the
cyclinE
gene,

cyclinE
1f36

. The rate of oogenesis is normal in

cyclinE
1f36

/

cyclinE
Pz8

mutant ovaries, indicating that increased replication fork progression is due to increased replication fork speed, possibly from increased processivity. The increased amplification domains observed in the mutant imply that there are not replication fork barriers preventing replication forks from progressing beyond the normal 100-kb amplified region. These results reveal a previously unrecognized role for CyclinE in controlling replication fork movement.
α-Helices direct excitation energy flow in the Fenna–Matthews–Olson protein
Authors: Müh Frank , Madjet Mohamed El-Amine , Adolphs Julia , Abdurahman Ayjamal , Rabenstein Björn , Ishikita Hiroshi , Knapp Ernst-Walter , Renger Thomas
Published: October 2007

In photosynthesis, light is captured by antenna proteins. These proteins transfer the excitation energy with almost 100% quantum efficiency to the reaction centers, where charge separation takes place. The time scale and pathways of this transfer are controlled by the protein scaffold, which holds the pigments at optimal geometry and tunes their excitation energies (site energies). The detailed understanding of the tuning of site energies by the protein has been an unsolved problem since the first high-resolution crystal structure of a light-harvesting antenna appeared >30 years ago [Fenna RE, Matthews BW (1975)
Nature
258:573–577]. Here, we present a combined quantum chemical/electrostatic approach to compute site energies that considers the whole protein in atomic detail and provides the missing link between crystallography and spectroscopy. The calculation of site energies of the Fenna–Matthews–Olson protein results in optical spectra that are in quantitative agreement with experiment and reveals an unexpectedly strong influence of the backbone of two α-helices. The electric field from the latter defines the direction of excitation energy flow in the Fenna–Matthews–Olson protein, whereas the effects of amino acid side chains, hitherto thought to be crucial, largely compensate each other. This result challenges the current view of how energy flow is regulated in pigment–protein complexes and demonstrates that attention has to be paid to the backbone architecture.
Wonderful varieties of type 𝖤
Authors: Bravi Paolo
Published: October 2007

The classification of spherical varieties is already known for semi- simple groups of types

A

\mathsf A

and

D

\mathsf D

. Adding type

E

\mathsf E

, we complete the classification for all semisimple groups with a simply laced Dynkin diagram.
Regulation of vascular morphogenesis by Notch signaling
Authors: Roca Cristina , Adams Ralf H.
Published: October 2007

The Notch pathway is a versatile regulator of cell fate specification, growth, differentiation, and patterning processes in metazoan organisms. In the vertebrate cardiovascular system, multiple Notch family receptors and several of their Jagged and Delta-like ligands are expressed during critical stages of embryonic and postnatal development. Functional studies in mice, fish, tumor models, and cell culture systems have shown that the angiogenic growth of the blood vessel network, the proliferation of endothelial cells, and the differentiation of arteries and veins are controlled by Notch signaling. Moreover, Notch pathway components play important roles in human pathological conditions involving the vasculature, namely CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) and Alagille syndrome. Recent findings highlight the Notch ligand Delta-like 4 as a key regulator of tumor angiogenesis and suggest that this protein might be a promising target for cancer therapy.
The genetics of hereditary colon cancer
Authors: Rustgi Anil K.
Published: October 2007

The genetic basis of sporadic colorectal cancer has illuminated our knowledge of human cancer genetics. This has been facilitated and catalyzed by an appreciation and deep understanding of the forms of colorectal cancer that harbor an inherited predisposition, including familial adenomatous polyposis (FAP), hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome, the hamartomatous polyposis syndromes, and certain other rare syndromes. Identification of germline mutations in pivotal genes underlying the inherited forms of colorectal cancer has yielded many dividends, including functional dissection of critical molecular pathways that have been revealed to be important in development, cellular homeostasis, and cancer; new approaches in chemoprevention, molecular diagnostics and genetic testing, and therapy; and underscoring genotypic–phenotypic relationships.
Novel Plant Transformation Vectors Containing the Superpromoter
Authors: Lee Lan-Ying , Kononov Maria E. , Bassuner Burgund , Frame Bronwyn R. , Wang Kan , Gelvin Stanton B.
Published: October 2007

We developed novel plasmids and T-DNA binary vectors that incorporate a modified and more useful form of the superpromoter. The superpromoter consists of a trimer of the octopine synthase transcriptional activating element affixed to the mannopine synthase2′ (mas2′) transcriptional activating element plus minimal promoter. We tested a superpromoter-β-glucuronidaseA fusion gene in stably transformed tobacco (Nicotiana tabacum) and maize (Zea mays) plants and in transiently transformed maize Black Mexican Sweet protoplasts. In both tobacco and maize, superpromoter activity was much greater in roots than in leaves. In tobacco, superpromoter activity was greater in mature leaves than in young leaves, whereas in maize activity differed little among the tested aerial portions of the plant. When compared with other commonly used promoters (cauliflower mosaic virus 35S, mas2′, and maize ubiquitin), superpromoter activity was approximately equivalent to those of the other promoters in both maize Black Mexican Sweet suspension cells and in stably transformed maize plants. The addition of a maize ubiquitin intron downstream of the superpromoter did not enhance activity in stably transformed maize.
The sea and archaeology
Authors: McGrail Seán
Published: October 2007

Man has been a seafarer for at least 40,000 years, and must have used raft or boat on lakes and rivers at an even earlier date. Maritime archaeologists seek evidence for such activities from earliest times until written records predominate. Direct evidence for water transport is not available before 8,000 B.C. and is biased towards Egypt and Europe. Much archaeological, environmental, ethnographic and experimental research is required to fill the great temporal and spatial gaps in our knowledge of the prehistoric maritime past. For later centuries, archaeologists can complement the work of historians: in this article examples of such work are given and assessed.
Edward Sexby, John Reynolds and Edmund Chillenden: Agitators, ‘sectarian grandees’ and the relations of the New Model Army with London in the spring of 1647
Authors: Norris Michael A.
Published: October 2007

This article seeks to revise our view of the connections between the New Model Army and London at the time of its so-called revolt in the spring of 1647. Specifically, it is concerned with identifying the author(s) responsible for a series of important documents that have been traditionally attributed to Trooper Edward Sexby. A re-reading of key sources suggests that a group of high-ranking officers channelled soldierly concerns for the payment of arrears and indemnity into principled resistance of parliamentary orders for their disbandment. Working through the agency of Captain John Reynolds and Lieutenant Edmund Chillenden, these officers appear to have sponsored the activities of the emerging Agitator movement.
United Kingdom government aid
Authors: Tyson S. , Gordon M.
Published: October 2007

The Department for International Development (DFID) is the UK government department with responsibility for managing Britain's aid to poor countries, with an overall budget of £5.3 billion in 2007–8. Our health strategy is to strengthen healthcare systems by working in partnership with governments and other stakeholders in public health in assisted countries. DFID also supports a substantial research programme, principally in health and education.
Anaesthesia and hospital links: strengthening healthcare through South‐North hospital partnerships
Authors: Parry E. H. O. , Percy D. B.
Published: October 2007

Health services can respond to the needs of the poorest people in developing countries if those who work in the front line of health care are supported and motivated and if development needs in services and training programmes can be filled. This can be achieved when a Health Link between a southern hospital and/or training school and its northern counterpart is designed to build a disciplined and long‐term programme of staff development including the needs of anaesthetic services, which meets the needs identified by the southern partner. Development of anaesthetic practice is best carried out in the context of an institution‐wide Health Link where not only the staff and systems involved in anaesthesia but all the essential ‘back office’ or support services are also supported and developed.
Intensive care in the developing world
Authors: Towey R. M. , Ojara S.
Published: October 2007

Appropriate and sustainable intensive care practice is possible even in the resource‐limited locations of sub‐Saharan Africa. Data from seven sub‐Saharan African countries indicates that the majority of patients served are surgical. Comparison between intensive care units is difficult due to lack of laboratory support, which precludes the severity sickness scores used internationally. Hospital mortality can be reduced by increasing nurse/patient ratios, adequate monitoring and initiating postoperative intermittent positive pressure ventilation when required. Equipment should include appropriate technology, for instance using oxygen concentrators and a ventilator not dependent on compressed gases or disposable circuits. The clinical officer anaesthetist has a major role to play in the intensive care team.
Ketamine
Authors: Craven R.
Published: October 2007

Ketamine is a very versatile inexpensive drug and plays an invaluable role in the developing world. In regions where access and funding for a wider range of drugs is problematic, its broad range of clinical applications is ideal. Its good safety profile and ease of storage makes it ideal for use in areas where refrigerators, complex monitoring, electricity and oxygen may all be in short supply or unreliable. Ketamine is also finding increasing use in both the acute and chronic pain settings and research is still ongoing into a potential neuroprotective effect for ketamine in brain injury.
The International Relations Committee of the Association of Anaesthetists of Great Britain and Ireland
Authors: Aitken H. , O'Sullivan E.
Published: October 2007

The International Relations Committee of the Association of Anaesthetists of Great Britain and Ireland was established over 30 years ago to assist anaesthetists working in developing countries. The committee has attempted to make an impact through distribution of educational materials, supporting training courses and investing in a number of small equipment projects. In 2005, the Overseas Anaesthesia Fund was set up to allow members to donate directly to support our work.
The Global Oximetry Initiative
Authors: Thoms G. M. M. , McHugh G. A. , O'Sullivan E.
Published: October 2007

Global Oximetry (GO) is an initiative launched recently in Uganda, India, the Philippines and Vietnam. The overall aims are to promote oximetry utilisation and reduce oximetry costs in lower income countries. Research objectives include studying the feasibility of cost reduction; overcoming non‐cost barriers to global oximetry including issues of prioritisation; education and guidelines; servicing and access to parts. Promotional objectives include creating new policy, influencing oximetry design, and setting new global standards for safer monitoring.
Employment opportunities with international agencies, mission organisations and government hospitals
Authors: Frossard J. , Bojarska A.
Published: October 2007

This article describes work with aid agencies in different developing countries. In addition to providing anaesthesia, the aim should be to increase resources and sustainability of local practice, irrespective of the duration of the visit. This article describes the background to some of the international aid agencies and our experience working with the International Committee of the Red Cross, Médecins Sans Frontières, and Response International, as well as various other mission organisations.
Specialist surgery in the developing world: luxury or necessity?
Authors: Wright I. G. , Walker I. A. , Yacoub M. H.
Published: October 2007

Patients suffering from conditions requiring specialist intervention cannot obtain treatment when facilities do not exist locally. Specialist visiting teams in a number of surgical disciplines have attempted to address these issues in collaboration with local clinicians. These interventions require careful planning and communication to achieve optimum results. Several teams have been successful in building long‐term relationships that have lead to important clinical developments in the local country.
A review of the efficacy of dexamethasone in the prevention of postoperative nausea and vomiting
Authors: Warren Amii , King Lindy
Published: October 2007

Aims of the review.  To consider the efficacy of dexamethasone in preventing postoperative nausea and vomiting following general anaesthesia and a range of surgical procedures, compared with a placebo of sodium chloride (normal saline). To inform nurses’ pharmacological knowledge of the effects of this medication during peri‐operative care.

Background.  Dexamethasone was serendipitously discovered to have an effect on reducing postoperative nausea and vomiting for patients receiving various chemotherapeutic regimes. Experience suggests many nurses remain unaware of the anti‐emetic effect of this medication.

Methods.  Multiple databases were searched and selected articles were restricted to experiments published within the past 10 years. Participants of each study had received dexamethasone or sodium chloride (not administered in combination with any other anti‐emetics) preoperatively, undergone general anaesthesia and received a common surgical procedure. Thirteen research articles met these criteria and were reviewed.

Results.  The surgical procedures represented have shown high incidences of postoperative nausea and vomiting associated with them. Importantly, 12 of the 13 trials reported significant reductions suggesting dexamethasone has a significant preventative effect in reducing the incidence of postoperative nausea and vomiting when given during induction. However, as a preventative of postoperative nausea alone, dexamethasone does not appear to have a significant effect.

Conclusions.  The findings clearly support the notion that dexamethasone does have anti‐emetic properties. Research examining dexamethasone in combination with other drugs as a cocktail of anti‐emetics is welcomed. Future research into the usefulness of dexamethasone given beyond the induction period as an anti‐emetic to inform postoperative protocols of care is needed.

Relevance to clinical practice.  Nurses in the peri‐operative arena can administer this medication, when ordered, with the knowledge based on research evidence as to why it has been included in preoperative protocols. However, dexamethasone has been noted in postanaesthesia recovery care units as a clinical pathway option for the management of postoperative nausea and vomiting and no retrieved articles discuss this option.
Effectiveness of a prenatal education programme on breastfeeding outcomes in Taiwan
Authors: Lin Shu‐Shan , Chien Li‐Yin , Tai Chen‐Jei , Lee Ching‐Fang
Published: October 2007

Aims.  The objectives of this study were to design a structured prenatal education programme on breastfeeding and to evaluate the effectiveness of the programme. Indicators of effectiveness were selected based on Kirkpatrick's Training Evaluation Model, including satisfaction with the programme, breastfeeding knowledge, breastfeeding attitude, breastfeeding satisfaction, breastfeeding problems and rate of exclusive breastfeeding.

Methods.  This study applied a quasi‐experimental design. The experimental group included 46 women who received a 90‐minute group educational programme on breastfeeding during their 20th–36th week of pregnancy. Each experimental subject was matched by a control subject according to age, educational level, work status and pregnancy gestational age. Control subjects did not receive any intervention. Data were collected through self‐administered questionnaires at preintervention, postintervention, three days postpartum and one month postpartum.

Results.  Satisfaction with the programme was high. The experimental group had higher scores in breastfeeding knowledge and breastfeeding attitude at three days postpartum. The experimental group showed higher breastfeeding satisfaction at three days and one month postpartum. There were no significant differences in experiencing breastfeeding problems. The rate of exclusive breastfeeding was higher for the experimental group at three days and one month postpartum, but the differences were not statistically significant.

Conclusion.  This study demonstrated the effectiveness of a prenatal education programme on maternal knowledge, attitude and satisfaction toward breastfeeding.

Relevance to clinical practice.  Other hospitals could apply this model to plan and evaluate their prenatal education programme on breastfeeding.
Birthweight and the risk of childhood sensorineural hearing loss
Authors: Engdahl Bo , Eskild Anne
Published: October 2007

The aim of this study was to estimate the impact of birthweight on the risk of sensorineural hearing loss in children. The study was a nested case–control study. Cases (n = 327) were identified through the Norwegian county registers of children with hearing loss, and controls (n = 391 992) were all children without hearing loss born in the same counties, identified through the Norwegian Medical Birth Registry of Norway. Case definition was mean sensorineural hearing loss (MHL) ≥35 decibel (dB) hearing level (HL) in the better‐hearing ear averaged over the pure‐tone hearing thresholds at 500, 1000 and 2000 Hz, diagnosed before the age of 5 years. Birthweight <1500 g, as compared with 3500–3999 g, gave an adjusted odds ratio for sensorineural hearing loss of 6.3 [95% CI 2.4, 16.4], controlled for gestational age, gender, parity, maternal age and concurrent birth defects. The risk of hearing loss decreased with increasing birthweights, with adjusted odds ratios of 4.4, 3.8, 1.7 and 1.4 for the birthweights 1500–1999, 2000–2499, 2500–2999 and 3000–3499 g respectively. The risk of both mild to moderate (MHL 35–70 dBHL) and severe/profound hearing losses (MHL >70 dBHL) were influenced by birthweight.
Type 1 diabetes risk analysis on dried blood spot samples from population‐based newborns: design and feasibility of an unselected case–control study
Authors: Eising Stefanie , Svensson Jannet , Skogstrand Kristin , Nilsson Anita , Lynch Kristian , Andersen Paal Skytt , Lernmark Åke , Hougaard David M. , Pociot Flemming , Nørgaard‐Pedersen Bent , Nerup Jørn
Published: October 2007

Development of type 1 diabetes mellitus (T1D) may be triggered pre‐ or perinatally by multiple factors. Identifying new predisposing T1D markers or combinations of markers in a large, well‐characterised case–control collection may be important for future T1D prevention. The present work describes the design and feasibility of a large and unselected case–control study, which will define and evaluate prediction criteria for T1D at the time of birth.

Danish registries (Biological Specimen Bank for Neonatal Screening, and the National Discharge Registry) made it possible to identify and collect dried blood spots (DBS) from newborns who later developed T1D (cases) born 1981–2002. DBS samples from 2086 cases and two matching control subjects per case were analysed for genetic and immune factors that are associated with T1D: (a) candidate genes (HLA, INS and CTLA4), (b) cytokines and inflammatory markers, (c) islet auto‐antibodies (GAD65A, IA‐2A).

The objective of the study was to define reliable prediction tools for T1D using samples available at the time of birth. In a unique approach, the study linked a large unselected and population‐based sample resource to well‐ascertained clinical databases and advanced technology. It combined genetic, immunological and demographic data to develop prediction algorithms. It also provided a resource for future studies in which new genetic markers can be included as they are identified.
Changing risks of stillbirth and neonatal mortality associated with maternal age in Western Australia 1984–2003
Authors: O'Leary Colleen M. , Bower Carol , Knuiman Matthew , Stanley Fiona J.
Published: October 2007

There has been a trend over the past two decades in some Western countries for women to delay childbearing, a factor associated with an increased risk of perinatal mortality (stillbirth and neonatal death). While the rates of stillbirth and neonatal mortality have improved in some countries, it has not been established whether maternal age remains a risk factor for perinatal mortality in Australia. The Western Australian Maternal and Child Health Research Database (MCHRDB) was used to examine the effect of maternal age on perinatal death in the periods 1984–93 and 1994–2003 after adjustment for parity and sociodemographic factors. Stillbirths and neonatal deaths were analysed separately.

The crude rate of stillbirth has shown little change over the 20 years examined remaining at around 7.5 per 1000 total births, while the rate of neonatal death has decreased steadily from 5.4 per 1000 livebirths in 1984 to 2.0 in 2003. Older maternal age remains a risk factor for stillbirth but the relative risk has declined. After adjustment for parity and sociodemographic factors the relative risk of stillbirth for a woman aged over 40 years (compared with a woman aged 25–29 years) decreased from 2.6 in the period 1984–93, to 1.9 in the period 1994–2003. The increased risk of stillbirth associated with teenage mothers was fully explained by sociodemographic factors in both time periods. No increased risk of neonatal death was evident in the recent period 1994–2003 for teenage or older mothers after adjustment for parity and sociodemographic factors. In spite of some improvements over the past 20 years, women 30 years of age and older continue to be at increased risk of stillbirth. The risk of neonatal death is no longer associated with increased maternal age; however, the small number of cases in the older maternal age groups may be a result of the increased prevalence of antenatal screening and terminations for birth defects.
Congenital toxoplasmosis: late pregnancy infections detected by neonatal screening and maternal serological testing at delivery
Authors: Lago Eleonor G. , Neto Eurico C. , Melamed Jacobo , Rucks Ana P. , Presotto Carolina , Coelho Jaqueline C. , Parise Cassiana , Vargas Paula R. , Goldbeck Ana S. , Fiori Renato M.
Published: October 2007

The first aim of this study was to determine the prevalence of congenital toxoplasmosis in newborn infants treated by the public health system in Porto Alegre, a city in southern Brazil, using neonatal screening for Toxoplasma gondii‐specific IgM. The second aim was to investigate whether the cases detected by this approach could have been identified by the prenatal screening for antibodies to T. gondii that was performed in the same population. A fluorometric assay was used to analyse T. gondii‐specific IgM in filter paper specimens obtained from newborn infants for routine screening for metabolic diseases. When the specific IgM was positive, serum samples from the infant and the mother were requested for confirmatory serological testing, and the infant underwent clinical examination.

Among 10 000 infants screened for T. gondii‐specific IgM, seven filter paper samples were positive, and congenital toxoplasmosis was confirmed in six patients. The prevalence of IgM specific for T. gondii was 6/10 000 [95% CI 2/10 000, 13/10 000]. One infected infant had already been identified in the maternity ward before birth, three had been identified by maternal serology at delivery, and two infants with congenital toxoplasmosis were identified solely through neonatal screening. Although four mothers of the patients with congenital toxoplasmosis received prenatal care, and three mothers had one or two serological tests for T. gondii‐specific antibodies (one at first trimester, one at first and second trimesters, and the other at second and third trimesters), they were not identified during pregnancy as infected. Neonatal screening identified cases of infection not detected by obtaining only one or two serum samples from pregnant women for T. gondii serology, mainly when infection was acquired and transmitted in late pregnancy. Maternal serology at delivery and neonatal screening were especially useful in the identification of infants with congenital toxoplasmosis when the mother did not receive regular prenatal serological testing or prenatal care.