bluuebunny/crossref_metadata_2025 huggingface dataset:
ZnO nanocoral structures for photoelectrochemical cells
Authors: Ahn Kwang-Soon , Yan Yanfa , Shet Sudhakar , Jones Kim , Deutsch Todd , Turner John , Al-Jassim Mowafak
Published: October 2008

We report on synthesis of a uniform and large area of a new form of ZnO nanocorals. These nanostructures can provide suitable electrical pathways for efficient carrier collection as well as large surface areas for the photoelectrochemical (PEC) cells. PEC devices made from these ZnO nanocoral structures demonstrate significantly enhanced photoresponse as compared to ZnO compact and nanorod films. Our results suggest that the nanocoral structures could be an excellent choice for nanomaterial-based applications such as dye-sensitized solar cells, electrochromic windows, and batteries.
Equilibrium and magnetic properties of a rotating plasma annulus
Authors: Wang Zhehui , Si Jiahe , Liu Wei , Li Hui
Published: October 2008

Local linear analysis shows that magneto-rotational instability can be excited in laboratory rotating plasmas with a density of 1019m−3, a temperature on the order of 10eV, and a magnetic field on the order of 100G. A laboratory plasma annulus experiment with a dimension of ∼1m, and rotation at ∼0.5 sound speed is described. Correspondingly, magnetic Reynolds number of these plasmas is ∼1000, and magnetic Prandtl number ranges from about one to a few hundred. A radial equilibrium, ρUθ2∕r=d(p+Bz2∕2μ0)∕dr=K0, with K0 being a nonzero constant, is proposed for the experimental data. Plasma rotation is observed to drive a quasisteady diamagnetic electrical current (rotational current drive) in a high-β plasma annulus. The rotational energy depends on the direction and the magnitude of the externally applied magnetic field. Radial current (Jr) is produced through biasing the center rod at a negative electric potential relative to the outer wall. Jr×Bz torque generates and sustains the plasma rotation. Rotational current drive can reverse the direction of vacuum magnetic field, satisfying a necessary condition for self-generated closed magnetic flux surfaces inside plasmas. The Hall term is found to be substantial and therefore needs to be included in the Ohm’s law for the plasmas. Azimuthal magnetic field (Bθ) is found to be comparable with the externally applied vacuum magnetic field Bz, and mainly caused by the electric current flowing in the center cylinder; thus, Bθ∝r−1. Magnetic fluctuations are anisotropic, radial-dependent, and contain many Fourier modes below the ion cyclotron frequency. Further theoretical analysis reflecting these observations is needed to interpret the magnetic fluctuations.
Probing thermal waves on the free surface of various media: Surface fluctuation specular reflection spectroscopy
Authors: Tay A. , Thibierge C. , Fournier D. , Fretigny C. , Lequeux F. , Monteux C. , Roger J. P. , Talini L.
Published: October 2008

Thermal motion gives rise to fluctuations in free surfaces; measurement of the thermally excited waves on such surfaces provides information on the mechanical properties of the medium. We have developed an optical tool to probe the thermally excited waves on free surfaces: surface fluctuation specular reflection (SFSR) spectroscopy. It consists in measuring the fluctuations in the position of a laser beam that is specularly reflected onto the free surface of a medium. The position of the reflected beam is sensitive to the roughness of the probed surface; the thermal waves are detected by subtracting the light intensities collected on the two quadrants of a photodiode, on which the beam is centered. We show how the measured signal is related to the medium properties. We also present measurements performed on Newtonian liquids as well as on a viscoelastic solid; we show that in all cases, there is a very good agreement between experimental and computed spectra. SFSR thus applies to a broad range of materials. It moreover offers a very good temporal resolution and should provide a useful tool for dynamical measurements on complex fluids.
Angle dependence of planar Hall resistance and anisotropic magnetoresistance of (Ga,Mn)As and Permalloy microdevices
Authors: Jung M. H. , Park S. , Eom J. , Chun S. H. , Shin K.
Published: October 2008

We present systematic studies on the angle dependence of planar Hall resistance and anisotropic magnetoresistance of ferromagnetic semiconductor (Ga,Mn)As and metallic Permalloy (Py) microdevices. (Ga,Mn)As shows two distinct planar Hall resistance switchings when the magnetic field is applied in the plane, indicating the magnetization reversal by 90° due to the cubic magnetocrystalline anisotropy. Similar magnetization reversal is observed in metallic Py microdevices. The broader planar Hall resistance jump observed in the Py device is attributed to the uniaxial shape anisotropy and complex domain rotation at the voltage probe. Nevertheless the observed planar Hall effect of Py is comparable to that of (Ga,Mn)As.
The effect of phase separation on the temperature dependent magnetoresistance in perovskite oxide heterojunction
Authors: Hu Chun-lian , Jin Kui-juan , Han Peng , Lu Hui-bin , Liao Leng , Yang Guo-zhen
Published: October 2008

The interesting behavior of the magnetoresistance at various temperatures for the heterojunction of La0.9Sr0.1MnO3∕SrNb0.01Ti0.99O3 is well explained based on the phase separation scenario. The good agreement between the theoretical and experimental results reveals that the mechanism for the variation in magnetoresistance with temperature and with the magnetic field is the competition between the positive magnetoresistance in the paramagnetic phase caused by the interface effect of the La0.9Sr0.1MnO3∕SrNb0.01Ti0.99O3 p-n heterojunction and the negative magnetoresistance in the ferromagnetic phase of the La0.9Sr0.1MnO3 film, respectively.
Magnetic structure near the Co∕NiO(001) interface
Authors: Arenholz Elke , van der Laan Gerrit , Nolting Frithjof
Published: October 2008

We investigate the magnetic coupling at the Co∕NiO interface using soft x-ray magnetic linear dichroism (XMLD) and circular dichroism taking explicitly into account the recently observed angular dependence of the XMLD with respect to the crystallographic axes. We find that the Co moments are aligned perpendicular to the NiO moments. We discuss the impact of the anisotropic XMLD on the intensity ratio of the two peaks at the NiL2 edge, which is commonly employed to determine the spin orientation in antiferromagnets using XMLD.
Fabrication of 0.5 nm electrode gaps using self-breaking technique
Authors: Tsutsui Makusu , Taniguchi Masateru , Kawai Tomoji
Published: October 2008

Control of electrode gap size formed by a self-breaking method is explored by statistically investigating electric field dependence of the gap distance using nanofabricated mechanically controllable break junctions. We obtained narrow distributions of the electrode gap size around 0.5 nm at biases below a threshold field. The self-breaking technique has thus been demonstrated to be a reliable tool for fabricating electrodes with subnanometer size gaps.
Geometric dephasing-limited Hanle effect in long-distance lateral silicon spin transport devices
Authors: Huang Biqin , Jang Hyuk-Jae , Appelbaum Ian
Published: October 2008

Evidence of spin precession and dephasing (“Hanle effect”) induced by a magnetic field is the only unequivocal proof of spin-polarized conduction electron transport in semiconductor devices. However, when spin dephasing is very strong, Hanle effect in a uniaxial magnetic field can be impossible to measure. Using a silicon device with lateral injector-detector separation of over 2 mm and geometrically induced dephasing making spin transport completely incoherent, we show experimentally and theoretically that Hanle effect can still be measured using a two-axis magnetic field.
Optical moiré as a visualization tool for living vascular cell contraction force mapping
Authors: Zheng Xiaoyu , Zhang Xin
Published: October 2008

This letter reports an approach for cell contraction force mapping by utilizing optical moiré effect. We cultured living cells on patterned polymer substrates and studied the diffraction moiré patterns. We found that the flexible moiré patterns generated on the periodic substrates are capable of mapping cell contraction force evolution in whole field. We demonstrated one- and two-dimensional force mappings in vascular cells. Due to moiré magnification, this imaging approach can provide a versatile visual tool for mapping the cell-substrate interactions in living cells.
Gain coefficient method for amplified spontaneous emission in thin waveguided film of a conjugated polymer
Authors: Silvestre I. , Marques P. W. B. , Valadares M. , Cury L. A.
Published: October 2008

A method based on the unidimensional gain equation has been developed in order to fit the experimental data due to amplification of spontaneous emission in a thin film of conjugated polymer waveguide. The results have confirmed not only a dependence of the gain coefficient on the laser intensity but also on the length of the excitation laser stripe. The results are presented as a function of the average intensity in W/cm2, which is a manner to express the threshold intensity for a direct comparison between different materials, independent of the setup used.
Splitting of valance subbands in the wurtzite c-plane InGaN/GaN quantum well structure
Authors: Song Yu , Chen Dong , Wang Lai , Li Hongtao , Xi Guangyi , Jiang Yang
Published: October 2008

Peak splitting in the low temperature photoluminescence (PL) spectra of c-plane InGaN/GaN single quantum well samples was observed. For the k∥c configuration, the splitting peaks show a variation in relative intensity as the excitation power is tuned. For the k⊥c configuration, a strong polarization dependence of the luminescence distribution and intensity was spotted. The PL spectra was analyzed with a calculation model based on the k⋅p effective mass theory, and the splitting peaks were identified as free-exciton transitions between the conduction subband C1 and two groups of valence subbands, the {HH1,LH1} and the {HH2,LH2,CH1}, respectively.
An on-chip liquid tunable grating using multiphase droplet microfluidics
Authors: Chin L. K. , Liu A. Q. , Zhang J. B. , Lim C. S. , Soh Y. C.
Published: October 2008

This letter reports the realization of liquid tunable long-period grating (LPG) using multiphase droplet microfluidics that is integrated onto a microfluidic chip. A stream of plugs is formed by two immiscible liquids and acted as LPG. It provides the tunability in the grating period by tuning the flow rates of the liquids, the refractive index and the index variation of the core layer by using different combinations of liquids. The experimental results show attenuation strength of 0.14 and attenuation bandwidth of 7.6nm. The chip is promising as a sensor for biochemical applications and a tunable filter for optical measurement.
Insights into the structural dynamics of the Hsp110–Hsp70 interaction reveal the mechanism for nucleotide exchange activity
Authors: Andréasson Claes , Fiaux Jocelyne , Rampelt Heike , Druffel-Augustin Silke , Bukau Bernd
Published: October 2008

Hsp110 proteins are relatives of canonical Hsp70 chaperones and are expressed abundantly in the eukaryotic cytosol. Recently, it has become clear that Hsp110 proteins are essential nucleotide exchange factors (NEFs) for Hsp70 chaperones. Here, we report the architecture of the complex between the yeast Hsp110, Sse1, and its cognate Hsp70 partner, Ssa1, as revealed by hydrogen–deuterium exchange analysis and site-specific cross-linking. The two nucleotide-binding domains (NBDs) of Sse1 and Ssa1 are positioned to face each other and form extensive contacts between opposite lobes of their NBDs. A second contact with the periphery of the Ssa1 NBD lobe II is likely mediated via the protruding C-terminal α-helical subdomain of Sse1. To address the mechanism of catalyzed nucleotide exchange, we have compared the hydrogen exchange characteristics of the Ssa1 NBD in complex with either Sse1 or the yeast homologs of the NEFs HspBP1 and Bag-1. We find that Sse1 exploits a Bag-1-like mechanism to catalyze nucleotide release, which involves opening of the Ssa1 NBD by tilting lobe II. Thus, Hsp110 proteins use a unique binding mode to catalyze nucleotide release from Hsp70s by a functionally convergent mechanism.
Roles of RIG-I N-terminal tandem CARD and splice variant in TRIM25-mediated antiviral signal transduction
Authors: Gack Michaela U. , Kirchhofer Axel , Shin Young C. , Inn Kyung-Soo , Liang Chengyu , Cui Sheng , Myong Sua , Ha Taekjip , Hopfner Karl-Peter , Jung Jae U.
Published: October 2008

The caspase recruitment domain (CARD) of intracellular adaptors and sensors plays a critical role in the assembly of signaling complexes involved in innate host defense against pathogens and in the regulation of inflammatory responses. The cytosolic receptor retinoic acid-inducible gene-I (RIG-I) recognizes viral RNA in a 5′-triphosphate-dependent manner and initiates an antiviral signaling cascade. Upon viral infection, the N-terminal CARDs of RIG-I undergo the K
63
-linked ubiquitination induced by tripartite motif protein 25 (TRIM25), critical for the interaction of RIG-I with its downstream signaling partner MAVS/VISA/IPS-1/Cardif. Here, we demonstrate the distinct roles of RIG-I first and second CARD in TRIM25-mediated RIG-I ubiquitination: TRIM25 binds the RIG-I first CARD and subsequently ubiquitinates its second CARD. The T
55
I mutation in RIG-I first CARD abolishes TRIM25 interaction, whereas the K
172
R mutation in the second CARD eliminates polyubiquitin attachment. The necessity of the intact tandem CARD for RIG-I function is further evidenced by a RIG-I splice variant (SV) whose expression is robustly up-regulated upon viral infection. The RIG-I SV carries a short deletion (amino acids 36–80) within the first CARD and thereby loses TRIM25 binding, CARD ubiquitination, and downstream signaling ability. Furthermore, because of its robust inhibition of virus-induced RIG-I multimerization and RIG-I-MAVS signaling complex formation, this SV effectively suppresses the RIG-I-mediated IFN-β production. This study not only elucidates the vital role of the intact tandem CARD for TRIM25-mediated RIG-I activation but also identifies the RIG-I SV as an off-switch regulator of its own signaling pathway.
Kinase requirements in human cells: II. Genetic interaction screens identify kinase requirements following HPV16 E7 expression in cancer cells
Authors: Baldwin Amy , Li Wenliang , Grace Miranda , Pearlberg Joseph , Harlow Ed , Münger Karl , Grueneberg Dorre A.
Published: October 2008

Human papillomavirus (HPV) oncoproteins subvert cellular signaling pathways, including kinase pathways, during the carcinogenic process. To identify kinases targeted by the HPV16 E7 oncoprotein, shRNA kinase screens were performed in RKO colorectal carcinoma cell lines that differ only in their expression of HPV16 E7. Our screens identified kinases that were essential for the survival of RKO cells, but not essential for RKO cells expressing HPV16 E7. These kinases include CDK6, ERBB3, FYN, AAK1, and TSSK2. We show that, as predicted, CDK6 knockdown inhibits pRb phosphorylation and induces S-phase depletion, thereby inhibiting cell viability. Knockdown of ERBB3, FYN, AAK1, and TSSK2 induces a similar loss of cell viability through an unknown mechanism. Expression of the HPV16 E7 oncoprotein, known to bind and degrade pRb, relieves the requirement of these kinases. These studies demonstate that expression of a single oncoprotein can dramatically alter kinase sensitivity in human cells. The shRNA screens used here perform analogously to genetic interaction screens commonly used in genetically tractable organisms such as yeast, and thus represent an exciting method for unbiased identification of cellular signaling pathways targeted by cancer mutations.
Systematic review of clinical trials of acupuncture‐related therapies for primary dysmenorrhea
Authors: YANG HUAN , LIU CUN‐ZHI , YANG HUAN , LIU CUN‐ZHI , CHEN XU , MA LIANG‐XIAO , XIE JIE‐PING , GUO NAN‐NAN , MA ZENG‐BIN , ZHENG YUAN‐YUAN , ZHU JIANG , LIU JIAN‐PING
Published: October 2008

Background. Acupuncture‐related therapies might be an effective intervention for primary dysmenorrhea. Objective. To evaluate the effects of acupuncture‐related therapies for treating primary dysmenorrhea. Search Strategy. A specified literature search was performed of the Cochrane Library, MEDLINE, EMBASE, CNKI, and CBM databases. Selection criteria. All clinical controlled trials pertaining to acupuncture‐related therapies for primary dysmenorrhea were included, and the quality of the trials was assessed. Data collection and analysis. Two independent reviewers were responsible for data extraction and assessment. The original data of each trial were analyzed with software (Revman 4.2), but a meta‐analysis could not be carried out because of the heterogeneity of the trials. Main Results. Thirty randomized controlled trails (RCTs) and two controlled clinical trials (CCTs) were identified. Most of the trials were of low methodologic quality (six trials were Grade B and 26 trials were Grade C). Data analysis indicated that there were conflicting results regarding whether acupuncture‐related therapies were more effective than control treatments. However, there was a small, methodologic sound trial of acupuncture which suggested that acupuncture was more effective than control groups (placebo acupuncture: WMD=−0.57 and 95% CI=−0.76–0.38; standard control: WMD=−.19 and 95% CI=−0.37–0.01; visitation control: WMD=−1.04 and 95% CI=−1.28–0.80). Conclusions. Because of low methodologic quality and small sample size, there is no convincing evidence for acupuncture in the treatment of primary dysmenorrhea. There is an urgent need for randomized, blinded, placebo‐controlled trials to assess the effects of acupuncture.
Prenatal buprenorphine exposure: Effects on biochemical markers of hypoxia and early neonatal outcome
Authors: KAHILA HANNA , STEFANOVIC VEDRAN , LOUKOVAARA MIKKO , ALFTHAN HENRIK , HÄMÄLÄINEN ESA , HALMESMÄKI ERJA
Published: October 2008

Objective. To evaluate the possible association between prenatal buprenorphine exposure and compromised early neonatal outcome in view of markers of perinatal hypoxia. Design, setting and sample. The study group consisted of 27 full‐term neonates exposed to buprenorphine prenatally and prospectively followed up at a special tertiary outpatient clinic for pregnant drug abusers. Serving as controls were 27 full‐term neonates exposed prenatally to illicit substances other than opioids and 38 full‐term neonates from uncomplicated pregnancies of healthy parturients. Methods and main outcome measures. Apgar scores, cord pH and base excess were recorded. Cord serum samples were collected at birth for analysis of biochemical markers of fetal hypoxic stress: erythropoietin (EPO; chronic hypoxia), cardiac troponin T (cardiac involvement) and S100 (neural damage). Results. All infants were born in good condition according to Apgar scores and pH of cord blood. No statistically significant differences were found between the three groups in cord serum concentrations of EPO (33.0 median, range: 9.0–476.0 U/L in the buprenorphine‐exposed group vs 27.0, range: 8.0–114.0U/L in substance‐abusing controls vs 28.1, range: 11.6–260.0U/L in healthy controls) or S100 (0.47, range: 0.25–0.91µg/L vs 0.40, range: 0.12–1.22µg/L vs 0.47, range: 0.20–2.15µg/L). No significant differences existed in cardiac TnT levels (0.017, range: 0.010–0.072U/L vs 0.010, range: 0.010–0.075U/L vs 0.024, range: 0.010–0.075U/L). Conclusions. While no significant differences in asphyxia markers were observed between the three groups, a tendency towards higher levels of EPO emerged in the buprenorphine‐exposed group.
Survival of ovarian cancer patients in Denmark: Excess mortality risk analysis of five‐year relative survival in the period 1978–2002
Authors: HANNIBAL CHARLOTTE GERD , CORTES RIKKE , ENGHOLM GERDA , KJAER SUSANNE KRÜGER
Published: October 2008

Objective. To explore the variation in ovarian cancer survival in Denmark in the period 1978–2002 in relation to time since diagnosis, age at diagnosis, period of diagnosis, stage and histology. Design. Register‐based cohort study. Setting. Denmark in the period 1978–2002. Population. Using the nationwide Danish Cancer Registry, we included a total of 13,035 women diagnosed with invasive ovarian cancer in Denmark in the period 1978–2002. Methods. Excess mortality risk analyses of five‐year relative survival of ovarian cancer patients diagnosed in the period 1978–2002 with follow‐up through 2006 were made based on data from the NORDCAN database. Main outcome measures. Five‐year relative survival, excess mortality rate (ER) and relative excess mortality risk (RER) after an ovarian cancer diagnosis. Results. The relative survival of Danish ovarian cancer patients slightly increased in the period 1978–2002. The ERs were highest in the first year following diagnosis, in particular in the first three months, and among older patients, even for localized and regional tumors. The pattern remained the same when stratified by histological subgroup. Older age at diagnosis, earlier period of diagnosis, more advanced stage at diagnosis and being diagnosed with undifferentiated carcinoma predicted poorer survival among Danish ovarian cancer patients diagnosed in the period 1978–2002. Conclusions. The survival of Danish ovarian cancer patients has slightly increased from 1978 through 2002. Despite this, the mortality rate of ovarian cancer in Denmark is still higher than in the other Nordic countries. Explanations for these differences are still to be identified.
Uterus transplantation: How far away from human trials?
Authors: BRÄNNSTRÖM MATS , WRANNING CAIZA A.
Published: October 2008

Uterus transplantation is being developed as a possible future method to treat uterus factor infertility. This commentary gives an overview of the animal research that has been conducted in preparation for human uterus transplantation. In addition, requirements for further specific research activities within the field are identified. It is our prediction that uterus transplantation will be introduced as an experimental procedure in the human within a few years.
Theoretical Models for Regulation of Blood Flow
Authors: SECOMB TIMOTHY W.
Published: October 2008

Blood‐flow rate in the normal microcirculation is regulated to meet the metabolic demands of the tissues, which vary widely with position and with time, but is relatively unaffected by changes of arterial pressure over a considerable range. The regulation of blood flow is achieved by the combined effects of multiple interacting mechanisms, including sensitivity to pressure, flow rate, metabolite levels, and neural signals. The main effectors of flow regulation, the arterioles and small arteries, are located at a distance from the regions of tissue that they supply. Flow regulation requires the sensing of metabolic and hemodynamic conditions and the transfer of information about tissue metabolic status to upstream vessels. Theoretical approaches can contribute to the understanding of flow regulation by providing quantitative descriptions of the mechanisms involved, by showing how these mechanisms interact in networks of interconnected microvessels supplying metabolically active tissues, and by establishing relationships between regulatory processes occurring at the microvascular level and variations of metabolic activity and perfusion in whole tissues. Here, a review is presented of previous and current theoretical approaches for investigating the regulation of blood flow in the microcirculation.
A new methodological framework to implement an RFID project and its application
Authors: Battini Daria , Faccio Maurizio , Persona Alessandro , Sgarbossa Fabio
Published: October 2008

The introduction of new technologies in the industrial field has consistently seen the development of several different projects: some have been carried out successfully and others have encountered many difficulties, resulting in the failure of the projects. Often this is caused by the lack of the correct methodology to tackle the project and to understand how the new technology could be used in industrial applications. At present, radio frequency identification (RFID) technology represents a new tool of support for the automation of the processes and the improvement of the operating management of a system, being the missing link between the material flow and the information flow. RFID technology is used in a large number of possible applications, like product tracking, animal identification, inventory systems and others. However, in recent years, an inconsistent increase of such applications has been observed, due to the diverse information available on such technology and to the lack of a support methodology for this technology in the project management. For these reasons and above all due to the lack of methodological project supporting tools, many projects fail or are not implemented. After a brief introduction about RFID technology, this paper analyses the scientific contributions and the recent industrial applications of this new technology. Soon after, a new methodological framework is introduced in order to face the feasibility study for the application of RFID technology (born from the authors’ experience in the field), illustrating some pilot cases that have exceeded today the experimentation phase.
Performance increase and benefit compensation in supply chains by partial information sharing and billing based on identification of returnable transport items
Authors: Uckelmann Dieter , Hamann Tilo , Zschintzsch Markus
Published: October 2008

The hypothesis of performance-increase and benefit compensation within supply chains by partial information sharing and billing based on radio frequency identification (RFID) is verified within this paper. The concept is evaluated in a pilot project within the beverage industry. In supply chains, partial information sharing can be achieved based on RFID tags. In the pilot study, the tags are used to identify returnable transport items (RTI), because identification at item level would be too costly. The proposed integration of a billing system shall enable a compensation of benefits throughout the supply chain. In a first step, the billing model of the RTI pool operator is based on the proposed infrastructure. This approach is generic enough, though, to be adapted to many other scenarios and industries. A detailed description of RTI is given within the first paragraph. In the second paragraph, the technical applicability of ultra-high frequency (UHF) within the beverage supply chain is evaluated, and the modelling of the beverage supply chain is described. After logistical evaluation in Section 3, the fourth section describes the integration of a billing model. The pilot project carried out by the Bremen Research Cluster for Dynamics in Logistics was started in April 2008 to validate the proposed model in a real scenario within the beverage industry.
Rare peptide segments are found significantly more often in proto-oncoproteins than control proteins: implications for immunology and oncology
Authors: Trost Brett , Kanduc Darja , Kusalik Anthony
Published: October 2008

There is some evidence to suggest that peptide segments that are found rarely or never in the host proteome play a role in the immune response to disease-related proteins, both those derived from microbes and those derived from the host itself. We conjecture that this pattern may extend to human proto-oncoproteins. Our hypothesis in this study is that the frequency of rare peptide segments in sets of human proto-oncoproteins is significantly higher than in sets of control proteins, and we show that this is the case. Possible immunological implications of this observation are discussed.
A differential thermal expansion approach to crystal structure determination from powder diffraction data
Authors: Fernandes P. , Shankland K. , David W. I. F. , Markvardsen A. J. , Florence A. J. , Shankland N. , Leech C. K.
Published: October 2008

Differential thermal expansion over the range 90–210 K has been applied successfully to determine the crystal structure of chlorothiazide from synchrotron powder diffraction data using direct methods. Key to the success of the approach is the use of a multi-data-set Pawley refinement to extract a set of reflection intensities that is more `single-crystal-like' than those extracted from a single data set. The improvement in reflection intensity estimates is quantified by comparison with reference single-crystal intensities.
Determination of depth gradients of grain interaction and stress in Cu thin films
Authors: Wohlschlögel M. , Baumann W. , Welzel U. , Mittemeijer E. J.
Published: October 2008

Grain-interaction and residual stress depth gradients in a sputter-deposited Cu thin film (thickness 4 µm) were determined by employing X-ray diffraction stress measurements at constant information depths in the range between 200 and about 1500 nm. A novel procedure, which allows the determination of an effective grain-interaction parameter on the basis of thef(ψ,hkl) method and the Voigt and Reuss models of elastic grain interaction, was used. The range of accessible penetration depths was maximized by employing different photon energies using a laboratory diffractometer with Cu Kα radiation and a diffractometer at a synchrotron beamline. The variation of grain interaction with depth could be successfully related to the microstructure of the specimen. The tensile residual stress in the film parallel to its surface decreases with decreasing depth. By measuring the lattice spacing for several reflections at one penetration depth with two different photon energies (i.e.using small and large incident beam angles) it was found that the surface roughness of the specimen counteracts the effect of beam refraction to some degree. As a consequence, irrespective of whether a refraction correction is applied or neglected for the low-incidence angle measurement, erroneous results are obtained for lattice spacings derived from reflections at small incidence angles; reliable grain-interaction and stress analysis requires measurements at high incidence angle.
Transmyocardial Laser Revascularization
Authors: Anderson Jacqueline J.
Published: October 2008

Transmyocardial laser revascularization is an alternative treatment option for patients with refractory angina who are not suitable candidates for more conventional coronary intervention or surgery. The laser creates channels that provide blood flow from the left ventricular chamber to areas of ischemic myocardium. Results have been impressive with patients reporting a reduction in angina of two classes according to the Canadian Heart Association Angina Classification. Care of the patient post transmyocardial laser revascularization procedure is comparable to that of other cardiac surgery patients. Innovations in this relatively new procedure include less invasive approaches and using it as an adjunctive or delivery modality for gene therapy.
A Closer Look at Compliance Research in Heart Failure Patients in the Last Decade
Authors: Evangelista Lorraine S. , Dracup Kathleen
Published: October 2008

Compliance with a complex healthcare regimen is required of most patients with heart failure. Noncompliance with even some aspects of the recommended treatment can lead to repeated and preventable hospitalizations, or even death. This paper reviews the extent of noncompliance for general health‐seeking behavior and recommended lifestyle modifications in the general population, as well as the research on compliance conducted specifically in patients with heart failure. Research findings are reviewed in three areas: the extent and predictors of compliance, the relationship of compliance and clinical outcomes, and interventions designed to increase compliance in heart failure patients. Based on research findings to date, strategies to enhance compliance are offered.
Anatomical comparison of wild-type and non-nodulating mutant chickpea (Cicer arietinum)
Authors: Matthews Leslie J. , Davis Thomas M.
Published: October 2008

Non-nodulating chickpea (Cicer arietinum L.) mutant PM233B was characterized anatomically via comparison with its normally nodulating parent line ICC 640. Root hair and cortical cell infection threads, cortical cell division centers, and nodule formation were observed by light microscopy in serial root sections of ICC 640, but were absent in PM233B. Scanning electron microscope observations of inoculated root sections showed that ICC 640 and PM233B were indistinguishable in adsorption of chickpea Rhizobium strain CC1192. Thus, the rhizobial infection process was blocked in PM233B at a stage subsequent to root hair adsorption of bacteria, but prior to initiation of infection threads and root cortical cell division. Reciprocal shoot grafts between ICC 640 and PM233B demonstrated that the non-nodulation phenotype of PM233B was controlled by the root, and not the shoot, genotype. Key words: chickpea, Cicer arietinum, root nodule, symbiosis, non-nodulating mutant.
Further investigations of vegetative compatibility within Fusarium oxysporum f.sp. melonis
Authors: Jacobson D. J. , Gordon T. R.
Published: October 2008

One hundred and nineteen strains of Fusarium oxysporum f.sp. melonis were characterized by virulence and vegetative compatibility. One hundred and seven strains were placed in four previously reported vegetative compatibility groups: 0130, 0131, 0133, and 0134. Four strains were placed in three new vegetative compatibility groups, and the remaining eight strains were vegetatively self-incompatible. Two of the three new vegetative compatibility groups shared similar geographic origins and distribution with two previously reported vegetative compatibility groups; the third represented a more isolated infestation. All vegetatively self-incompatible isolates originated from culture collections; none have been recently isolated from nature. These newly characterized strains extend our knowledge of genetic diversity in F. oxysporum f.sp. melonis. All four F. oxysporum f.sp. melonis races exist in more than one vegetative compatibility group. European strains represent four vegetative compatibility groups, one of which is present in North America and another in the Middle East. The significance of this diversity is unknown, as are the phylogenetic relationships among strains in this forma specialis.
Cytological aspects of interactions between formae speciales of Erysiphe graminis and genera of gramineous plants, and their evolutionary implications
Authors: Tosa Y. , Akiyama T. , Ogura H.
Published: October 2008

The progress of infection in leaves of wheat (Triticum aestivum), rye (Secale cereale), wheatgrass (Agropyron tsukushiense), barley (Hordeum vulgare), and oat (Avena sativa) inoculated with Erysiphe graminis f.sp. tritici, secalis, agropyri, and hordei was observed using a fluorescence microscope. Relative compatibility of each host–parasite combination was estimated by the incidence of cell wall penetration. Formae speciales tritici, secalis, and agropyri were highly compatible with any accession of wheat, rye, and wheatgrass, but less compatible with barley. On the other hand, f.sp. hordei was highly compatible with any of these four hosts. The four formae speciales had very low compatibility with oat, although f.sp. hordei was relatively more compatible with this host. These results suggested that (i) f.sp. tritici, secalis, and agropyri are phylogenetically very close; (ii) f.sp. hordei is less close to f.sp. tritici, secalis, and agropyri, and closer than these to the ancestral form of E. graminis; (iii) f.sp. avenae is remote from f.sp. tritici, secalis, agropyri, and hordei, but relatively less remote from f.sp. hordei than from the other three formae speciales.
Physiological factors determining vesicular–arbuscular mycorrhizal formation in host and nonhost Ri T-DNA transformed roots
Authors: Bécard G. , Piché Y.
Published: October 2008

Transformed roots of carrot (Umbelliferae) and sugar beet (Chenopodiaceae) were used as model host and nonhost plant, respectively, for the vesicular–arbuscular mycorrhizal fungus Gigaspora margarita (Becker & Hall). Rapid growth of hyphae from germinating spores of G. margarita and formation of infection units were obtained only in the presence of carrot roots. Root volatiles from both plant species have similar stimulative effects on hyphal growth. However, hyphal growth was stimulated by root exudates of carrot and not by those of sugar beet. These and other results suggest that the nonmycorrhizal roots of sugar beet lack factors that promote mycorrhizal infection rather than producing inhibitory factors. The model used in this study is especially appropriate for further investigations on the recognition mechanisms involved in vesicular–arbuscular mycorrhizal associations.
Structural studies of asparagus spear infection by Stemphylium
Authors: Sutherland P. W. , Hallett I. C. , Parkes S. L. , Templeton M. D.
Published: October 2008

Three types of lesion occur on spears of asparagus (Asparagus officinalis) infected with a Stemphylium sp. : limited, spreading, and fleck. The pathogen enters the host via stomata. Host cellular changes are restricted to the epidermis and cortex. In the limited lesion type of infection, there is a rapid cytoplasmic degeneration of host cells, beginning close to the penetrating hyphae, but eventually also occurring at a distance from these. Electron-dense material accumulates in the intercellular spaces and envelops the hyphae. Hyphae, the contents of which become disorganised, occupy only a small part of the central area of the lesion. The spreading type of lesion is much larger than the limited type. Electron-dense material is absent, and hyphae ramify throughout the intercellular spaces of the lesion. The third type, a fleck lesion, develops in response to inoculation of Stemphylium isolates nonpathogenic to asparagus. Electron-dense material is produced before stomatal penetration is complete, and hyphae fail to penetrate beyond the substomatal cavity. Only a few host cells are degraded. Application of concentrated culture fluids of a pathogenic Stemphylium isolate to excised asparagus spears failed to produce disease symptoms on either wounded or unwounded tissue.
Vegetative remains of the Magnoliaceae from the Princeton chert (Middle Eocene) of British Columbia
Authors: Cevallos-Ferriz Sergio R. S. , Stockey Ruth A.
Published: October 2008

One wood block and many small twigs (up to 1.3 cm diam.) with little secondary growth and showing magnoliaceous characters were identified from the Princeton chert locality (Middle Eocene) of British Columbia, Canada. Specimens were studied with a modified cellulose acetate peel technique and hydrofluoric acid. Well-preserved primary tissues include a chambered pith that distinguishes these twigs from other woods in the chert. Secondary xylem has solitary vessels, radial multiples, and clusters, scalariform perforation plates with 8–27 bars, scalariform, transitional, and opposite intervascular pitting, and tyloses. Imperforate tracheary elements with circular bordered pits, heterocellular and homocellular rays, and marginal parenchyma characterize the twigs. Secondary phloem has dilated rays, alternating bands of fibers and thin-walled cells, and sclerified ray and axial cells. In older wood, opposite intervascular pitting and homocellular rays, suggest affinities with Liriodendron L.; however, the presence of opposite, scalariform, and transitional intervascular pitting and secondary phloem structure necessitate its inclusion in Liriodendroxylon Prakash et al. Liriodendroxylon princetonensis Cevallos-Ferriz et Stockey sp.nov. is distinguished from other species in this genus by the presence of homocellular rays, scalariform intervascular pitting, and well-preserved extraxylary tissues that are unknown for the other fossil species. Liriodendroxylon princetonensis adds to the diversity of extinct magnoliaceous plants during the Eocene and represents the oldest known species of this genus. These plants were probably part of the surrounding forest vegetation in the Princeton basin. Like most extant Magnoliales, L. princetonensis probably lived under subtropical to warm-temperate, moist conditions. Key words: Magnoliaceae, Liriodendroxylon, fossil woods, Eocene.
Formation of wall appositions in leaves and lateral roots of an iron-accumulating pea mutant
Authors: Guinel F. C. , LaRue T. A.
Published: October 2008

E107 is a mutant of pea (Pisum sativum L. cv. Sparkle) characterized by necrotic spots on its leaves, high Fe accumulation in its shoot, and decreased nodulation. Fresh, cleared, and fixed tissues of the mutant and its parent were observed by light and electron microscopy. E107 has cell wall appositions in its basal leaflets and in the endodermis of its lateral roots. The wall deposits in the leaves are layered and contain callose and phenols. The appositional walls in the lateral root endodermis, made of lignin or of phenols, are not organised. We hypothesize that the appositions are stress responses to metal toxicity. Key words: pea mutant, wall appositions, histochemistry, iron toxicity.
Influence of epilithic microorganisms on the surface temperature of building walls
Authors: Garty Jacob
Published: October 2008

Despite numerous investigations on the role of epilithic microorganisms in the biodegradation and weathering of historical monuments, the influence of cyanobacteria (cyanophytes), green algae, and lichens on the surface temperature of outer walls of buildings is only poorly understood. Reported herein are the results of a combined microscopic and infrared imaging radiometry study focusing on the localization of microorganisms on mortar walls in Israel, and on the temperature regime on the surfaces of such colonized walls. We decided to investigate whether such lithobionts could affect the microclimate on and around buildings in rural and urban areas. Scanning electron microscopy revealed the presence of unicellular cyanobacteria, multicellular colonies of the cyanobacterium Gloeocapsa biformis st. dermochrous, and unicellular Trebouxia-like green algae on mortar wall surfaces. Older walls were found to be covered by the lichen Caloplaca citrina, which changed the blackish colour of these walls into a lemon yellow. We found that blackish surfaces on mortar walls colonized mostly by cyanobacteria were up to 8 °C warmer than noncolonized areas, which suggests that such microorganisms may affect the temperature regime on walls in built-up areas. Key words: lithobionts, infrared radiometry.
Antifungal activity of ajoene, a constituent of garlic (Allium sativum)
Authors: Singh U. P. , Pandey V. N. , Wagner K. G. , Singh K. P.
Published: October 2008

Ajoene, a compound derived from garlic (Allium sativum L.), inhibited spore germination of some fungi, namely, Alternaria solani, Alternaria tenuissima, Alternaria triticina, Alternaria sp., Colletotrichum sp., Curvularia sp., Fusarium lini, Fusarium oxysporum, Fusarium semitectum, and Fusarium udum, which cause serious diseases in some important crop plants in India. The compound was very effective in checking spore germination at a concentration of 25 μg/mL in some of the above fungi and, in most cases, there was 100% inhibition of germination at 100 μg/mL. It is quite likely that the compound may be useful in controlling disease(s) under field conditions.
Floral sex ratios in scrub oak (Quercus ilicifolia) vary with microtopography and stem height
Authors: Aizen Marcelo A. , Kenigsten Alejandra
Published: October 2008

We measured floral sex ratios (number of male inflorescences:number of female flowers) and height of stems (= ramets) of monoecious scrub oak (Quercus ilicifolia) growing along a topographic gradient on the slope of a 20 m deep depression. Stems lower in the gradient experienced increasingly severe conditions in terms of a shorter growing season and a higher incidence of killing frosts. At the top of the gradient, floral sex ratios of tall stems were male biased; however, sex allocation patterns at the bottom showed no such size-dependent relationship. With decreasing elevation (greater stress), the production of male flowers declined more rapidly than that of female flowers. Tall stems reduced overall resource allocation to flower production proportionately more with decreasing elevation than did short stems, but this reduction was again more marked in the male flowering function than in the female. These differential patterns of sex investment explain, at least in part, the variation in size-related gender relationships along this gradient. The more stressful environmental conditions prevailing at the bottom of the depression and the relative costs of the male and prezygotic female function may combine to produce these flowering patterns.
Cytochemical detection of polysaccharides in zoospores of Aphanomyces euteiches
Authors: Sadowski Laura A. , Powell Martha J.
Published: October 2008

Carbohydrates in thin-sectioned zoospores of the pea root pathogen Aphanomyces euteiches were ultrastructurally localized with the silver methenamine technique. The polysaccharide specificity of localization was verified with minus periodic acid or minus silver methenamine controls, with the sulfhydryl blocker iodoacetate, and with the dialdehyde blockers dimedone and sodium bisulfite. Reaction produce was found on the inner and outer surfaces of the plasma membrane and over the membranes of the water expulsion vacuole system. Inclusions within dense-body vacuoles were covered with reaction product, often in distinct zones. The central core region of K2-bodies, comprising an array of fibers, also contained carbohydrates. Little or no silver methenamine reaction product was found in peripheral vesicles or encystment vesicles, two organelles implicated in cell surface modifications during encystment. This study demonstrates that the cell surface of the unwalled zoospore contains carbohydrates and that the K2-body of A. euteiches, like the K2-body of Saprolegnia ferax, compartmentalizes carbohydrates. We conclude that K2-bodies found in zoospores of two different genera of Oomycetes are homologous organelles. Key words: carbohydrates, zoospore, Aphanomyces, K2-bodies, membranes.
A phylogenetic reconstruction of Antennaria (Asteraceae: Inuleae)
Authors: Bayer Randall J.
Published: October 2008

A cladistic analysis of 32 sexually reproducing species of Antennaria Gaertn. revealed that the genus comprises five constitutive monophyletic groups: Geyeriae, Argenteae, Dimorphae, Pulcherrimae, and Catipes. Three of the groups, Argenteae, Dimorphae, and Geyeriae, have retained relatively large numbers of plesiomorphic characters. The members of these three groups are mostly nonstoloniferous and have not evolved characters often associated with sexual dimorphism that occur in the remainder of Antennaria. Consequently these three groups closely resemble the suprageneric outgroup, Anaphalis and Gnaphalium. The Pulcherrimae and Catipes represent the most specialized groups. These two groups have wider distributions and occur in a much greater diversity of habitats than the Argenteae, Dimorphae, and Geyeriae. Evolutionary advancement in the genus has been toward dioecism and coincident sexual dimorphism, probably as a method to promote outcrossing. In addition, polyploidy and two asexual means of reproduction, agamospermy and horizontal stolons, have evolved in the more specialized groups, the Pulcherrimae and Catipes. Antennaria probably arose from Mexican Gnaphalium sometime during the Oligocene or Miocene, migrated into the western United States where it has evolved and migrated into other areas of the northern hemisphere and South America. Key words: Antennaria, Asteraceae, Inuleae, cladistics phylogeny, biogeography.