bluuebunny/crossref_metadata_2025 huggingface dataset:
Protective Effects of Beta Glucan and Gliclazide on Brain Tissue and Sciatic Nerve of Diabetic Rats Induced by Streptozosin
Authors: Alp Harun , Varol Sefer , Celik Muhammet Murat , Altas Murat , Evliyaoglu Osman , Tokgoz Orhan , Tanrıverdi Mehmet Halis , Uzar Ertugrul
Published: January 2012

There have not been yet enough studies about effects of beta glucan and gliclazide on oxidative stress created by streptozotocin in the brain and sciatic nerve of diabetic rats. The aim of this paper was to investigate the antioxidant effects of gliclazide and beta glucan on oxidative stress and lipid peroxidation created by streptozotosin in brain and sciatic nerve. Total of 42 rats were divided into 6 groups including control, diabetic untreated (DM) (only STZ, diabetic), STZ (DM) + beta glucan, STZ (DM) + gliclazide, only beta glucan treated (no diabetic), and only gliclazide treated (no diabetic). The brain and sciatic nerve tissue samples were analyzed for malondialdehyde (MDA), total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), and paraoxonase (PON-1) levels. We found a significant increase in MDA, TOS, and OSI along with a reduction in TAS level, catalase, and PON-1 activities in brain and sciatic nerve of streptozotocin-induced diabetic rats. Also, this study shows that in terms of these parameters both gliclazide and beta glucan have a neuroprotective effect on the brain and sciatic nerve of the streptozotocin-induced diabetic rat. Our conclusion was that gliclazide and beta glucan have antioxidant effects on the brain and sciatic nerve of the streptozotocin-induced diabetic rat.
Influence of Synthesis Conditions on the Physicochemical Properties and Catalytic Activity of Fe/Cr‐Pillared Bentonites
Authors: Tomul Fatma
Published: January 2012

The synthesis of Fe/Cr‐pillared bentonites starting from a 2% clay suspension and also from dry clay using ultrasound treatment for both the aging and the intercalation steps of the pillaring solution considerably reduces the time and the amount of water required compared with the conventional synthesis method. The catalysts were characterized using scanning electron microscopy with an energy dispersive system (SEM‐EDS), powder X‐ray diffraction (XRD), N2 and CO2‐adsorption/desorption, electron paramagnetic resonance (EPR), Fourier‐transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis and the catalytic activity of selected samples was evaluated for the phenol oxidation reaction. The results of XRD analysis showed that delaminated Fe/Cr‐pillared bentonite with d001 value 68 Å was observed after intercalation a direct mixture of the pillaring solution and dry clay. The adsorption‐desorption isotherm analysis showed that the samples synthesized with the proposed methodology in intercalation stage have similar textural properties and these properties do not change remarkably with synthesis conditions. In addition, the characterisation studies showed that the physicochemical properties of samples synthesized by ultrasound were comparable to those of sample synthesized by conventional method in this study. The sample synthesized by conventional method show 50% phenol conversion. This value was higher than those of samples synthesized by the ultrasound.
Serum CEACAM1 Correlates with Disease Progression and Survival in Malignant Melanoma Patients
Authors: Sivan Sapoznik , Suzan Faranesh , Rona Ortenberg , Tamar Hamburger , Vivian Barak , Tamar Peretz , Jacob Schachter , Gal Markel , Michal Lotem
Published: January 2012

The search for melanoma biomarkers is crucial, as the incidence of melanoma continues to rise. We have previously demonstrated that serum CEACAM1 (sCEACAM1) is secreted from melanoma cells and correlates with disease progression in metastatic melanoma patients. Here, we have used a different cohort of melanoma patients with regional or metastatic disease (N=49), treated with autologous vaccination. By monitoring sCEACAM1 in serum samples obtained prior to and after vaccination, we show that sCEACAM1 correlates with disease state, overall survival, and S100B. The trend of change in sCEACAM1 following vaccination (increase/decrease) inversely correlates with overall survival. DTH skin test is used to evaluate patients’ anti-melanoma immune response and to predict response to vaccination. Importantly, sCEACAM1 had a stronger prognostic value than that of DTH, and when sCEACAM1 decreased following treatment, this was the dominant predictor of increased survival. Collectively, our results point out the relevance of sCEACAM1 in monitoring melanoma patients.
Stepwise Diagnosis for Rotating Machinery Using Force Identification Approach
Authors: Kawamura Shozo , Niimi Kazuhiro , Kato Yuichi , Minamoto Hirofumi
Published: January 2012

Machine condition monitoring and diagnosis have become increasingly important, and the application of these processes has been widely investigated. The authors previously proposed a stepwise diagnosis method for a beam structure. In that method, the location of the abnormality is first estimated using the force identification approach, and then the cause of the abnormality is identified. In this study, the stepwise diagnosis method was improved specifically for rotating machinery. The applicability of the proposed method was checked by using the experimental data. In the case of a rotor system with unbalance, it was shown that the location of the abnormality and its severity could be identified, and, in the case of a rotor system with stationary rubbing, the location of the abnormality could be accurately identified. Therefore, it was confirmed that the proposed diagnostic method is feasible for actual application.
Measurement-Based Analysis of Transmit Antenna Selection for In-Cabin Distributed MIMO System
Authors: Zhang Yan , Li Zhenghui , Luan Fengyu , Xiao Limin , Zhou Shidong , Wang Jing
Published: January 2012

Aircraft seems to be the last isolated island where the wireless access is still not available. In this paper, we consider the distributed multiple-input multiple-output (D-MIMO) system application based on measurements in aircraft cabin. The channel response matrices of in-cabin D-MIMO system are collected by using a wideband channel sounder. Channel capacities with optimum transmit antenna selections (TASs) are calculated from the measured data at different receiver positions. Then the optimum capacity results are compared to those without selection in different transmit SNR. It is shown that the TAS can lead obvious capacity gain, especially in the front and back of cabin. The capacity gain represents a decreasing trend with the transmit SNR increasing. The optimal transmit antenna subset is closely related to the transmit SNR. With the SNR increasing, more transmit antennas will be chosen for higher performance. The subset of those transmit antennas near the receiver is a reasonable choice in practical application of D-MIMO system.
Cholinergic Regulation of Airway Inflammation and Remodelling
Authors: Kolahian Saeed , Gosens Reinoud
Published: January 2012

Acetylcholine is the predominant parasympathetic neurotransmitter in the airways that regulates bronchoconstriction and mucus secretion. Recent findings suggest that acetylcholine regulates additional functions in the airways, including inflammation and remodelling during inflammatory airway diseases. Moreover, it has become apparent that acetylcholine is synthesized by nonneuronal cells and tissues, including inflammatory cells and structural cells. In this paper, we will discuss the regulatory role of acetylcholine in inflammation and remodelling in which we will focus on the role of the airway smooth muscle cell as a target cell for acetylcholine that modulates inflammation and remodelling during respiratory diseases such as asthma and COPD.
WPG‐Controlled Quantum BDD Circuits with BDD Architecture on GaAs‐Based Hexagonal Nanowire Network Structure
Authors: ZHao Hong-Quan , Kasai Seiya
Published: January 2012

One‐dimensional nanowire quantum devices and basic quantum logic AND and OR unit on hexagonal nanowire units controlled by wrap gate (WPG) were designed and fabricated on GaAs‐based one‐dimensional electron gas (1‐DEG) regular nanowire network with hexagonal topology. These basic quantum logic units worked correctly at 35 K, and clear quantum conductance was achieved on the node device, logic AND circuit unit, and logic OR circuit unit. Binary‐decision‐diagram‐ (BDD‐) based arithmetic logic unit (ALU) is realized on GaAs‐based regular nanowire network with hexagonal topology by the same fabrication method as that of the quantum devices and basic circuits. This BDD‐based ALU circuit worked correctly at room temperature. Since these quantum devices and circuits are basic units of the BDD ALU combinational circuit, the possibility of integrating these quantum devices and basic quantum circuits into the BDD‐based quantum circuit with more complicated structures was discussed. We are prospecting the realization of quantum BDD combinational circuitries with very small of energy consumption and very high density of integration.
A Phenotypic Point of View of the Adaptive Radiation of Crested Newts (Triturus cristatus Superspecies, Caudata, Amphibia)
Authors: Ivanović Ana , Džukić Georg , Kalezić Miloš
Published: January 2012

The divergence in phenotype and habitat preference within the crested newt Triturus cristatus superspecies, examined across different ontogenetic stages, provides an excellent setting to explore the pattern of adaptive radiation. The crested newts form a well-supported monophyletic clade for which at least the full mitochondrial DNA phylogeny is resolved. Here we summarise studies that explored the variation in morphological (larval and adult body form, limb skeleton, and skull shape) and other phenotypic traits (early life history, developmental sequences, larval growth rate, and sexual dimorphism) to infer the magnitude and direction of evolutionary changes in crested newts. The phenotypic traits show a high level of concordance in the pattern of variation; there is a cline-like variation, from T. dobrogicus, via T. cristatus, T. carnifex, and T. macedonicus to the T. karelinii group. This pattern matches the cline of ecological preferences; T. dobrogicus is relatively aquatic, followed by T. cristatus. T. macedonicus, T. carnifex, and the T. karelinii group are relatively terrestrial. The observed pattern indicates that phenotypic diversification in crested newts emerged due to an evolutionary switch in ecological preferences. Furthermore, the pattern indicates that heterochronic changes, or changes in the timing and rate of development, underlie the observed phenotypic evolutionary diversification.
A Review of Geometric Optimal Control for Quantum Systems in Nuclear Magnetic Resonance
Authors: Bonnard Bernard , Glaser Steffen J. , Sugny Dominique
Published: January 2012

We present a geometric framework to analyze optimal control problems of uncoupled spin 1/2 particles occurring in nuclear magnetic resonance. According to the Pontryagin's maximum principle, the optimal trajectories are solutions of a pseudo-Hamiltonian system. This computation is completed by sufficient optimality conditions based on the concept of conjugate points related to Lagrangian singularities. This approach is applied to analyze two relevant optimal control issues in NMR: the saturation control problem, that is, the problem of steering in minimum time a single spin 1/2 particle from the equilibrium point to the zero magnetization vector, and the contrast imaging problem. The analysis is completed by numerical computations and experimental results.
Impact of Conventional Breath Inspiratory Time during High-Frequency Jet Ventilation in Preterm Lambs
Authors: Musk Gabrielle C. , Polglase Graeme R. , Song Yong , Pillow J. Jane
Published: January 2012

Background: Conventional mechanical ventilator (CMV) breaths during high-frequency jet ventilation (HFJV) are advocated to recruit and stabilize alveoli. Objectives: To establish if CMV breath duration delivered during HFJV influences gas exchange, lung mechanics and lung injury. Methods: Preterm lambs at 128 days gestational age were studied. HFJV (7 Hz, PEEP 8 cm H2O, PIPHFJV 40 cm H2O, FiO2 0.4) with superimposed CMV breaths (PIPCMV 25 cm H2O, rate 5 breaths/min) was commenced after delivery and continued for 2 h. CMV breath inspiratory time (tI) was either 0.5 s (HFJV+CMV0.5; n = 8) or 2.0 s (HFJV+CMV2.0; n = 8). Age-matched unventilated controls (UVC) were included for comparison. Results: Serial arterial blood gas analyses were performed. PIPHFJV was adjusted to target a PaCO2 of 45–55 mm Hg. FiO2 was adjusted to target SpO2 90–95%. Pressure-volume curves, broncho-alveolar lavage (BAL) and lung tissue samples were obtained postmortem. Gas exchange, ventilation parameters, static lung compliance and BAL inflammatory markers were not different between HFJV+CMV0.5 and HFJV+CMV2.0. Both ventilation groups had higher BAL inflammatory markers and increased iNOS-positive cells on histology compared to UVC, whilst lung tissue IL-1β and IL-6 mRNA expression was higher in the HFJV+CMV2.0 group compared to the UVC group. Conclusions: Preterm lambs were ventilated effectively with HFJV and 5 CMV breaths/min. CMV breath duration did not alter blood gas exchange, ventilation parameters, ex vivo static lung mechanics or markers of lung injury over a 2-hour study, although consistent trends towards increased inflammatory markers with the longer tI suggest greater risk of injury.
Sex Differences in Stroke Incidence and Survival in Hong Kong, 2000–2007
Authors: Wu S.H. , Ho S.C. , Chau P.H. , Goggins W. , Sham A. , Woo J.
Published: January 2012

Background: Few studies have examined the impact of sex across different age groups and over time on chronic diseases in Asia. The objective of this study was to explore the effect of sex across different age groups and over time on stroke incidence and 30-day case fatality in Hong Kong. Methods: Over 90% first hospitalizations for stroke in Hong Kong (from 2000 to 2007) were identified from the Clinical Management System of the Hospital Authority. Age-specific rate ratios (RRs; women to men) for incidence of first hospitalization and the 30-day case fatality were estimated based on Poisson regression models after adjustment for year of hospitalization. Results: Women below the age of 85 years had a lower incidence of first hospitalization than men, and the effect size varied with age [35–44 years: RR = 0.56, 95% confidence interval (CI) = 0.49–0.64; 45–54 years: 0.65, 0.53–0.79; 55–64 years: 0.58, 0.48–0.71; 65–74 years: 0.71, 0.58–0.85; 75–84 years: 0.83, 0.68–1.00)]. Women aged ≧85 years had a stroke incidence similar to men, but the adjusted 30-day case fatality was significantly higher than that of men aged ≧85 years (RR = 1.14, 95% CI = 1.05–1.23). Conclusions: Lower rates of incidence were observed in women than men aged 35–84 years in Hong Kong but short-term case fatality is greater in women aged ≧85 years.
From the ‘feminization of agriculture’ to the ‘ageing of farming populations’: Demographic transition and farming in a central Chinese village
Authors: Huang Yuqin
Published: January 2012

Great changes in terms of land and labour systems in rural China have been brought about by the economic reform in the late 1970s. The implementation of family planning policy and the tidal waves of rural-to-urban labour migration also caused demographic transitions. How have these changes affected the farming arrangements in rural China? Many suggest there has been a ‘feminization of agriculture’, while others insist it is not occurring. Based on quantitative information and ethnographic research in a central Chinese village, this article aims to reconcile the discrepancies between the discussions. It suggests that both sides might be correct in different contexts, taking into account the demographic transition among different cohorts of farming populations, regional differences in industrialization and levels of rural-to-urban labour migration. It proposes there has been a transition from the ‘feminization of agriculture’ to the ‘ageing of farming populations’ in the late 1990s, which implies a danger to farming in rural China when we ask: Who will be farming in 10 years’ time?
Transposing bodies of knowledge and technique: Animal models at work in reproductive sciences
Authors: Friese Carrie , Clarke Adele E.
Published: January 2012

A prominent feature of biological and biomedical research and therapeutics over the past century is the entanglement of human and other animal bodies in the making and remaking of knowledge, techniques and products. In this paper, we explore how animal models work in two different but interrelated situations: early/mid 20th-century reproductive sciences focused on human biomedicine; and early 21st-century assisted reproduction of endangered animals in zoos. We use the concept of ‘transposition’ to describe and compare how findings about different species, the infrastructures supporting different species and the body parts of different animal species have been mobilized at these sites. We show how such mobilizations create dynamic relationships in organizational, discursive and embodied ways. The two case studies illuminate the changing practices of modelling within the reproductive sciences, and the changing kinds of work animal models have done in those fields.
Active control of unbalance response of rotor systems supported by tilting-pad gas bearings
Authors: Lihua Y , Yanhua S , Lie Y
Published: January 2012

This article establishes an optimal control model using piezoelectric actuators, proportional–derivative (PD) compensation, and gap sensors to control the vibration of rotor systems supported by tilting-pad gas bearings with active pads. The optimal control law between the voltage applied on the actuator and dynamic displacement of rotor is obtained by means of conventional optimal control theory. Using this active control model, the unbalance responses of rotor system are numerically controlled. Results show that the unbalance responses of system can be effectively suppressed by this optimal control system. This article provides a theoretical basis for further improving the stability of rotor systems supported by tilting-pad gas bearings.
Measuring juvenile delinquency: How do self-reports compare with official police statistics?
Authors: van Batenburg-Eddes Tamara , Butte Dick , van de Looij-Jansen Petra , Schiethart Wiet , Raat Hein , de Waart Frouwkje , Jansen Wilma
Published: January 2012

The accuracy of measuring the prevalence of delinquency by means of self-reported questionnaires is difficult to evaluate. This study assesses the differential validity of self-reported delinquency in adolescents and, more specifically, self-reported police contacts because of suspected misconduct. This study was conducted as part of the Rotterdam Youth Monitor, a youth health surveillance system. Self-report data of pupils (mainly 12–15 years old) in the first or third grade of secondary school in the school years 2007–8 and 2008–9 ( n = 23,914) were merged with police data. Of the pupils registered as a suspect, 62 percent admitted to having been interrogated at the police station. However, there were differences between groups. Multivariate analysis showed that Moroccan pupils and first-grade pupils were more likely to give an invalid response. Pupils who were registered for theft, vandalism or assault were more likely to give a valid response, whereas pupils who were registered for an offence involving fireworks were more likely to give an invalid response. We conclude that using only self-reported data to measure delinquency in an ethnically diverse population results in substantial bias. It is advisable to use multiple sources to measure the prevalence of delinquency.
A fully validated method for the determination of arsenic species in rice and infant cereal products
Authors: Llorente-Mirandes Toni , Calderón Josep , López-Sánchez José Fermín , Centrich Francesc , Rubio Roser
Published: January 2012

A full validation of inorganic arsenic (iAs), methylarsonic acid (MA), and dimethyl arsinic acid (DMA) in several types of rice and rice-based infant cereals is reported. The analytical method was developed and validated in two laboratories. The extraction of the As species was performed using nitric acid 0.2 % and hydrogen peroxide 1 %, and the coupled system liquid chromatography-inductively coupled plasma-mass spectrometry (LCICP-MS) was used for speciation measurements. Detection limit (DL), quantification limit, linearity, precision, trueness, accuracy, selectivity, as well as expanded uncertainty for iAs, MA, and DMA were established. The certified reference materials (CRMs) (NMIJ 7503a, NCS ZC73008, NIST SRM 1568a) were used to check the accuracy. The method was shown to be satisfactory in two proficiency tests (PTs). The broad applicability of the method is shown from the results of analysis of 29 samples including several types of rice, rice products, and infant cereal products. Total As ranged from 40.1 to 323.7 μg As kg–1. From the speciation results, iAs was predominant, and DMA was detected in some samples while MA was not detected in any sample.
Applications of thin layer activation technique for the measurement of surface loss of materials: an Indian perspective
Authors: Chowdhury D. P. , Datta J. , Reddy A. V. R.
Published: January 2012

Thin layer activation (TLA) technique is a powerful nuclear technique based on the production of a radioisotope in the surface of a material by a charged particle induced nuclear reaction, followed by an estimation of the loss of the activity which is a measure of the surface loss of materials in the range of nanometer to hundreds of micrometer in the fields of wear, corrosion or erosion. The technique has been found to be a very useful tool in the basic scientific research and industrial applications. The present review describes the basic principle of TLA technique, its characteristic features, methodology, scope, applications and various recent developments regarding its growing use. Some of our earlier TLA work carried out with α and heavy ion (16O) in various applied areas is also included here. Heavy ions were used because no other light ions (particularly protons) were available at our cyclotron.
Radiotracers for SPECT imaging: current scenario and future prospects
Authors: Adak Sudeshna , Bhalla R. , Vijaya Raj K. K. , Mandal S. , Pickett R. , Luthra S. K.
Published: January 2012

Single photon emission computed tomography (SPECT) has been the cornerstone of nuclear medicine and today it is widely used to detect molecular changes in cardiovascular, neurological and oncological diseases. While SPECT has been available since the 1980s, advances in instrumentation hardware, software and the availability of new radiotracers that are creating a revival in SPECT imaging are reviewed in this paper.

The biggest change in the last decade has been the fusion of CT with SPECT, which has improved attenuation correction and image quality. Advances in collimator design, replacement of sodium iodide crystals in the detectors with cadmium zinc telluride (CZT) detectors as well as advances in software and reconstruction algorithms have all helped to retain SPECT as a much needed and used technology.

Today, a wide spectrum of radiotracers is available for use in cardiovascular, neurology and oncology applications. The development of several radiotracers for neurological disorders is briefly described in this review, including [123I]FP-CIT (DaTSCANTM) available for Parkinson's disease. In cardiology, while technetium-99m labeled tetrofosmin and technetium-99m labeled sestamibi have been well known for myocardial perfusion imaging, we describe a recently completed multicenter clinical study on the use of [123I]mIBG (AdreViewTM) for imaging in chronic heart failure patients. For oncology, while bone scanning has been prevalent, newer radiotracers that target cancer mechanisms are being developed. Technetium-99m labeled RGD peptides have been reported in the literature that can be used for imaging angiogenesis, while technetium-99m labeled duramycin has been used to image apoptosis.

While PET/CT is considered to be the more advanced technology particularly for oncology applications, SPECT continues to be the modality of choice and the workhorse in many hospitals and nuclear medicine centers. The cost of SPECT instruments also makes them more attractive in developing countries where the cost of a scan is still prohibitive for many patients.
Impact of water environmental change and migration of radionuclides on Hokutolite conservation in Peito (Taiwan)
Authors: Lin Chun-Chih , Tsai Tsuey-Lin , Lung Chia-Chi
Published: January 2012

Chemical factors (including pH, redox potential, content of total organic compound (TOC) and major ions) and U/Th-series radionuclides in the hot-spring water environment of Peito were determined to investigate the impact of environmental change and migration of radionuclides in water on conserving the precious mineral, hokutolite, in Peito (Taiwan). The activity concentrations of U/Th increased withEhand those of Cl−and SO42−.234U/238U ratios were nearly >1 ascribed to Szilárd–Chalmers effect andα-recoil.230Th/234U ratios were <1 resulting from complexation with chloride and sulfate ions.228Ra and226Ra activities were governed by pH,Ehand SO42−concentration. Disequilibria of228Th/228Ra and228Ra/232Th were evident attributed to complexation of Th with major anions and co-precipitation of radium with (Ba,Pb)SO4. Alpha-recoil caused the enrichment of228Ra and apparent disequilibrium of232Th/228Th. A mechanism illustrating the radiochemistry involving the formation of hokutolite in Peito was derived accordingly. The water environment of the studied area was found apparently changed in light of the variation of temperature, TOC and concentration ratio of Ba/Pb, which resulted from the channeling of hot spring water and the release of household waste water. The water environmental change can thus hinder the migration of radionuclides as well as the formation of hokutolite so that the performance of hokutolite conservation can be decreased. Immediate enactment of regulations for conserving hokutolite in Peito was therefore suggested in this research.
Depth dependent osmotic and swelling properties of cartilage
Authors: Silva Candida , Horkayne-Szakaly Iren , Chandran Preethi , Dimitriadis Emilios K. , Lin David , Papanicolas Christopher , Basser Peter J. , Horkay Ferenc
Published: January 2012

Articular cartilage is a low-friction, load-bearing tissue located at joint surfaces. It experiences static and dynamic forces including shear, compression and tension. We investigate the relationship between structure and function by measuring the osmotic and mechanical properties in cartilage layers as a function of the distance from the articular surface. Atomic force microscopy is used to probe the mechanical properties at high spatial resolution. The mechanical measurements are complemented by osmotic swelling pressure observations made on the same samples using a novel tissue osmometer. The results show that the osmotic modulus significantly depends on the distance from the articular surface. Its value is highest in the deep zone and lowest in the middle zone.
Examination of the properties of the interface of a-SiNx:H/Si in crystalline silicon solar cells and its effect on cell efficiency
Authors: Lamers Machteld W.P.E. , Butler Keith , Romijn Ingrid G. , Harding John , Weeber Arthur W.
Published: January 2012

Nitridation is the process in which, during the initial growth of a-SiNx:H layers on Si surfaces, nitrogen (N) is incorporated into Si lattice near its surface. We show that this nitridation process affects the density of interface states (Dit) and fixed charges (Qf) at the interface. These parameters determine the effective surface passivation quality of the layers. The nitridation can be tuned independently of the growth of a-SiNx:H layers by using a plasma treatment prior to actual a-SiNx:H layer deposition. It is shown that the Qf can be varied from 2·1012 to 15·1012 cm-2 without changing the a-SiNx:H deposition process. It is demonstrated that in our case and processing window, Qf is the determining factor in surface passivation quality in the range of 2·1012 to 8·1012 cm-2. For higher values of Qf, Dit has increased significantly and has become dominant thereby reducing the passivation quality. It is shown that the passivation can be controlled independently of the a-SiNx:H deposition process. On completed solar cells this variation in Qf due to nitridation results in a change in open-circuit voltage, Voc, of almost 20mV.
Measuring size-dependent mechanical properties of electrospun polystyrene fibers using in-situ AFM-SEM
Authors: Bailey Russell J. , Cortes-Ballesteros Beatriz , Zhang Hao , Wang Congwei , Barber Asa H.
Published: January 2012

The mechanical properties of individual electrospun polystyrene fibers with sub-micron diameters were measured using a combination of atomic force microscopy (AFM) and scanning electron microscopy (SEM). The strain to failure of the electrospun fibers was observed to increase as the fiber diameter decreased. This size dependent mechanical behavior in individual electrospun polystyrene fibers indicates a suppression of localized failure and a shift away from crazing that is dominant in bulk samples.
Template-Free Synthesis of Ellipsoidal Silica Nanoparticles
Authors: Zhang Henan , Akins Daniel L.
Published: January 2012

For a sol-gel process occurring in a water/oil (w/o) system, the self-assembly of silica nuclei can be controlled by close control of synthesis conditions. We have synthesized ellipsoidal or spherical silica particles by a template-free scheme that involves controlling surface tension on silica nuclei through via use of different volume ratios of a w/o micellar system.
Optical characterization of a InGaN/GaN microcavity with epitaxial AlInN/GaN bottom DBR
Authors: Franke A. , Bastek B. , Sterling S. , August O. , Petzold S. , Veit P. , Christen J. , Moser P. , Wieneke M. , Berger C. , Bläsing J. , Dadgar A. , Krost A.
Published: January 2012

Resonant coupling of an optical mode confined within a microcavity and an emitter is the basic prerequisite for the observation of Bose-Einstein condensation phenomena and the development of novel optical devices based on cavity polaritons.

We demonstrate highly spatially resolved 2” wafer characterization of the reflectivity and emission properties of a nitride based multi quantum well semi microcavity (i.e. structure without top Bragg reflector) to verify resonant regions. Photoluminescence and reflectivity spectra recorded at the same positions on the wafer exhibit a strong spatial dependence of the multi quantum well emission and the center wavelength of the stop band of the bottom Bragg reflector across the sample. Resonance, i.e., matching of the emission and the center wavelength of the stop band, is found in a region 8 mm off the center of the wafer.

The thickness profile across the AlInN/GaN Bragg reflector and multi quantum well layers was obtained by x-ray mappings over the full wafer. A perfect correlation between the local optical properties and the x-ray thickness distribution is found. Additional transmission electron microscopy investigations indicate a complete crack free structure and smooth interfaces between the layers within the Bragg reflector making the structure appropriate for strong coupling applications.
1.54μm luminescence of β-FeSi2 grown on Au-coated Si substrates
Authors: Akiyama Kensuke , Funakubo Hiroshi , Itakura Masaru
Published: January 2012

A clear PL spectrum was observed from β-FeSi2 grains on gold (Au)-coated (100)Si substrates, and indicated the formation of crystal with the same high quality level as the β-FeSi2 on a copper (Cu)-coated Si substrate. Moreover, the temperature dependence of photoluminescence peak intensities showed lower density of the nonradiative recombination center in β-FeSi2 grains on Au-coated Si substrates than that of β-FeSi2 film on Cu-coated Si. Au was not detected in β-FeSi2 grains by STEM-EDX observation, while Cu was observed in the grains and grain boundaries of β-FeSi2 and rolled as non-radiative recombination center.
Manipulating 3C-SiC Nanowire Morphology through Gas Flow Dynamics
Authors: Teker Kasif , Otto Jesse M.
Published: January 2012

Creation of nanoscale building blocks with various sizes and shapes are critical for the progress of nanotechnology. Silicon carbide nanostructures attract interest due to their applications in optoelectronic devices, sensors, high-power/high temperature electronics, and thermoelectrics. This paper presents a detailed study of SiC nanowire morphology change through gas flow dynamics. SiC nanowire synthesis has been carried out by chemical vapor deposition using hexamethyldisilane (HMDS) as source material on SiO2/Si substrate. The study has been limited to several catalyst materials, including nickel (nanoparticle and thin film), cobalt nanoparticles, and gold thin film. The growth runs have been carried out at 1000oC under H2 as carrier gas with flow rates varying from 100 to1000 sccm. A significant change in morphology has been observed. At high flow rates, the nanowires are highly curved and contain sharp kinks, while the nanowires are straight and longer at lower flow rates. Moreover, it is important to note that the flow rate has influenced the nanowire growth-yield significantly. As small as 8nm-diameter SiC nanowire has been observed, as determined by transmission electron microscopy (TEM). These findings will help in controlling the morphology of the SiC nanowires. The fabricated nanowires have also been characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR).
Alternative Sintering Approaches for Fast Sintering of Inkjet Printed Nanoparticles for R2R Applications
Authors: Perelaer Jolke , Schubert Ulrich S.
Published: January 2012

Within the last decades, inkjet printing technology has developed from only a text and graphic industry to a major topic of scientific research and R&D. Inkjet printing can be used as a highly reproducible non-contact patterning technique to print at high speeds either small or large areas with high quality features; it requires only small amounts of functional materials, which immediately favors production costs. Furthermore, inkjet printing reduces the amount of processing steps due to its additive technique of materials deposition, which further decreases productions costs as well as time.

This contribution provides a number of alternative approaches to sinter inkjet printed metal precursor materials at temperatures that are compatible with cost-effective polymer foils. The prepared features can serve as interconnects and contacts for microelectronic applications, such as OLED and OPV.
Mating Frequency and Fecundity in the Emerald Ash Borer Agrilus planipennis (Coleoptera: Buprestidae)
Authors: Rutledge Claire E , Keena Melody A
Published: January 2012

The consequences of single versus multiple mating on the longevity, fecundity, and fertility of female emerald ash borers Agrilus planipennis (Fairmaire) were examined. In the first treatment, dissections of the common oviduct showed that 43 of 52 singly-mated females had received spermatophores. In the next two treatments, females were observed to mate one time, then housed either alone (observed separate) or with their mate (observed together). In the fourth treatment, females were paired with a randomly chosen male (unobserved together). Weight (0.0428 ± SE 0.0008 g) and longevity (50.5 ± SE 1.6 d) of female beetles did not differ among treatments. Fecundity, but not fertility, had a significant positive correlation with longevity in all treatments. Almost all of the females ‘Observed together’ laid eggs (87%, N = 31), while significantly fewer females ‘unobserved together’ (61%, N = 31) and ‘Observed separate’ (54%, N = 31) did. The fecundity of females that did lay eggs did not differ among treatments. Based on our results a single mating may be sufficient to ensure maximal fecundity for females, but there is potential for failure of any one mating, and no apparent cost to multiple mating. Thus, multiple mating is likely the best strategy for female emerald ash borers to maximize fecundity. The implications of results for laboratory rearing, and potential population level effects are discussed.
Weed Vegetation of Sugarcane Cropping Systems of Northern Argentina: Data-Mining Methods for Assessing the Environmental and Management Effects on Species Composition
Authors: Ferraro D. O. , Ghersa C. M. , Rivero D. E.
Published: January 2012

Weed composition may vary because of natural environment, management practices, and their interactions. In this study we presented a systematic approach for analyzing the relative importance of environmental and management factors on weed composition of the most conspicuous species in sugarcane. A data-mining approach represented byk-means cluster and classification and regression trees (CART) were used for analyzing the 11 most frequent weeds recorded in sugarcane cropping systems of northern Argentina. Data of weed abundance and explanatory factors contained records from 1976 sugarcane fields over 2 consecutive years. Thek-means method selected five different weed clusters. One cluster contained 44% of the data and exhibited the lowest overall weed abundance. The other four clusters were dominated by three perennial species, bermudagrass, johnsongrass, and purple nutsedge, and the annual itchgrass. The CART model was able to explain 44% of the sugarcane's weed composition variability. Four of the five clusters were represented in the terminal nodes of the final CART model. Sugarcane burning before harvesting was the first factor selected in the CART, and all nodes resulting from this split were characterized by low abundance of weeds. Regarding the predictive power of the variables, rainfall and the genotype identity were the most important predictors. These results have management implications as they indicate that the genotype identity would be a more important factor than crop age when designing sugarcane weed management. Moreover, the abiotic control of crop–weed interaction would be more related to rainfall than the environmental heterogeneity related to soil type, for example soil fertility. Although all these exploratory patterns resulting from the CART data-mining procedure should be refined, it became clear that this information may be used to develop an experimental framework to study the factors driving weed assembly.
Seed Dormancy and Adaptive Seedling Emergence Timing in Giant Ragweed (Ambrosia trifida)
Authors: Schutte Brian J. , Regnier Emilie E. , Harrison S. Kent
Published: January 2012

Giant ragweed germination is delayed by both a physiological dormancy of the embryo (embryo dormancy) and an inhibitory influence of embryo-covering structures (covering structure-enforced [CSE] dormancy). To clarify the roles of embryo and CSE dormancy in giant ragweed seedling emergence timing, we conducted two experiments to address the following objectives: (1) determine changes in germinability for giant ragweed dispersal units (hereafter “involucres”) and their components under natural burial conditions, and (2) compare embryo and CSE dormancy alleviation and emergence periodicity between successional and agricultural populations. In Experiment 1, involucres were buried in crop fields at Columbus, OH, periodically excavated, and brought to the laboratory for dissection. Involucres, achenes, and embryos were then subjected to germination assays at 20 C. In Experiment 2, temporal patterns of seedling emergence were determined at a common burial site. Reductions in embryo and CSE dormancy were compared with controlled-environment stratification followed by germination assays at 12 and 20 C, temperatures representative of soil conditions in spring and summer. Results indicated that overwinter dormancy loss involved sequential reductions in embryo and CSE dormancy. CSE dormancy, which may limit potential for fatal germination during fall, was caused by the pericarp and/or embryo-covering structures within the pericarp. In Experiment 2, successional populations emerged synchronously in early spring, whereas agricultural populations emerged throughout the growing season. Levels of embryo dormancy were greater in the agricultural populations than the successional populations, but CSE dormancy levels were similar among populations. In 12 C germination assays, embryo dormancy levels were positively correlated with time required to reach 95% cumulative emergence (run 1:r= 0.81, P = 0.03; run 2:r= 0.76, P = 0.05). These results suggest that late-season emergence in giant ragweed involves high levels of embryo dormancy that prevent germination at low temperatures in spring.
Integrated Management Strategies Reduced Tall Ironweed (Vernonia altissima) Populations and Weed Biomass and Improved Tall Fescue Pasture Productivity
Authors: Tolson Josh A. , Green J. D. , Witt William W. , Schwab Greg J. , Omielan Joseph A.
Published: January 2012

Field studies were used to examine the management strategies of mowing, herbicide, fertility, and all possible combinations on tall ironweed populations, weed biomass, and pasture yield at three Kentucky locations. Mowing was performed in July 2008 and 2009, herbicide was applied in August 2008, and fertilizer was applied in September 2008 and 2009 at all locations. Weed populations were measured in 2008, 2009, and 2010, and forage grass, clover, and weed biomass was collected in May or early June of 2009 and 2010. All treatments with herbicide reduced tall ironweed stems by 64% or greater in 2009 at all locations. Mowing alone, fertilizer alone, and mowing plus fertilizer did not reduce tall ironweed populations, except at one location where mowing alone reduced tall ironweed stems by 64% in 2009. Tall ironweed stems were not reduced in 2010 with any treatment at two locations, but herbicide combined with mowing or fertilizer reduced tall ironweed stems by 78% at the other location. Tall goldenrod population was reduced up to 100% by all treatments with herbicide or mowing alone, and mowing with fertilizer reduced tall goldenrod from 59 to 89%. Treatments did not reduce horsenettle populations. Herbicide-containing treatments reduced weed biomass at all locations. Weed biomass did not differ when comparing all treatments with and without mowing or treatments with or without fertilizer. Forage grass biomass was greatest with herbicide plus fertilizer and with the combination of mowing plus herbicide plus fertilizer at all locations in both years.
The Influence of pH and Light on Hydrilla (Hydrilla verticillata) Photosynthesis and Chlorophyll after Exposure to Flumioxazin
Authors: Mudge Christopher R. , Bultemeier Brett W. , Haller William T.
Published: January 2012

Flumioxazin has recently (2010) been registered for aquatic use for control of hydrilla and other noxious invasive aquatic plant species. Due to the rapid degradation of flumioxazin, especially in high pH water, some hydrilla research trials have produced less than desirable results with rapid plant regrowth. Therefore, laboratory experiments were conducted to evaluate the influence of pH on flumioxazin's effect on photosynthesis. Flumioxazin applied at concentrations ≥ 200 µg ai L−1in high (9.0) pH water and ≥ 100 µg L−1in low (6.0) pH water required 68 to 123 h to reduce photosynthesis by 50% (ET50). The effect of 400 µg L−1flumioxazin on photosynthesis of apical hydrilla tips was also compared at low (20 µmol m−2s−1), medium (170 µmol m−2s−1), and high (400 µmol m−2s−1) light levels at pH 9.0. Low light–treated tips were still photosynthetic at approximately 73% of the nontreated control plants 168 h after treatment. Low light–treated hydrilla required an estimated 303 h to achieve a 50% reduction in photosynthesis, while high light plants only required 99 h. Chlorophyll content of hydrilla was reduced as flumioxazin concentration was increased from 100 to 1,600 µg L−1. These data indicate that flumioxazin activity on hydrilla photosynthesis is influenced by herbicide concentration, water pH, and light intensity.
An Herbicide-Susceptible Rigid Ryegrass (Lolium rigidum) Population Made Even More Susceptible
Authors: Manalil Sudheesh , Busi Roberto , Renton Michael , Powles Stephen B.
Published: January 2012

A wild population of a plant species, especially a cross-pollinated species, can display considerable genetic variation. Genetic variability is evident in differential susceptibility to an herbicide because the population can show continuous phenotypic variation. Recent, recurrent selection studies have revealed that phenotypic variation in response to low herbicide rates is heritable and can result in rapid evolution of herbicide resistance in genetically variable cross-pollinated rigid ryegrass. In this study, the heritable genetic variation in an herbicide-susceptible rigid ryegrass population was exploited to shift the population toward greater herbicide susceptibility by recurrent selection. To enhance herbicide susceptibility, herbicide-susceptible rigid ryegrass plants were divided into two identical clones, and one series of cloned plants was treated with a low rate of herbicide (diclofop). The nontreated clones of individuals that did not survive the herbicide treatment were selected and bulk-crossed to obtain the susceptible progeny. After two cycles of selection, the overall susceptibility to diclofop was doubled. The results indicate that minor genes for resistance are present in an herbicide-susceptible rigid ryegrass population, and their exclusion can increase susceptibility to diclofop.
A Glyphosate-Resistant Biotype of Annual Bluegrass in Tennessee
Authors: Brosnan James T. , Breeden Gregory K. , Mueller Thomas C.
Published: January 2012

Glyphosate is regularly used to control annual bluegrass populations in dormant bermudagrass turf. A population of annual bluegrass not controlled by glyphosate at 840 g ha−1(glyphosate resistant, GR) was identified on a golf course in Humboldt, TN in 2010. Mature tillers of GR plants were established in a greenhouse and treated with glyphosate at 0, 210, 420, 840, 1,680, 3,360, and 6,720 g ha−1. Mature tillers of a biotype known to be susceptible to glyphosate (SS) were also established in the greenhouse and subjected to the same treatments. At 14 d after treatment (DAT), glyphosate controlled the SS biotype > 95% at rates > 420 g ha−1. Comparatively, the GR biotype was only controlled 76% with glyphosate at 6,720 g ha−1. The rates required to provide 50% control (I50values) for SS and GR biotypes were 236 and 2,812 g ha−1respectively, resulting in a resistance factor of 12. Photochemical efficiency (Fv/Fm) values on SS plants treated with glyphosate at > 210 g ha−1measured 0.000 at 14 DAT, whereasFv/Fmvalues on GR plants were not significantly different from the untreated control with glyphosate rates ≤ 840 g ha−1on the same date. In laboratory experiments, the SS biotype accumulated greater shikimate concentrations than the GR biotype 3 to 6 DAT. Future research should evaluate strategies for managing GR and SS annual bluegrass with alternative modes of action.