bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of some pyrazole derivatives of 1,5‐diphenyl‐1H‐pyrazole‐3,4‐dicarboxylic acid
Authors: Kasımoğulları Rahmi , Seçkin Arslan B.
Published: July 2010

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Compound of 4‐(ethoxycarbonyl)‐1,5‐diphenyl‐1H‐pyrazole‐3‐carboxylic acid 2 was obtained from the reaction of ethyl 4,5‐dioxo‐2‐phenyl‐4,5‐dihydrofuran‐3‐carboxylate and 1‐benzylidene‐2‐phenylhydrazine. A number of substitute pyrazole dicarboxylic acid derivatives (4, 5a, 5b, 5c, 6, 7, 8, 9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i, 9j, 9k, 9l, 9m, 10, 11, 12, 13, 14) were synthesized from 1,5‐diphenyl‐1H‐pyrazole‐3,4‐dicarboxylic acid 3 which was prepared from basic hydrolysis of 2. Structures of synthesized compounds were characterized by 1H NMR, 13C NMR, Mass, FTIR, and elemental analysis. J. Heterocyclic Chem., (2010).
Bone marrow mononuclear cells protect neurons and modulate microglia in cell culture models of ischemic stroke
Authors: Sharma Sushil , Yang Bing , Strong Roger , Xi XiaoPei , Brenneman Miranda , Grotta James C. , Aronowski Jaroslaw , Savitz Sean I.
Published: July 2010

Although several studies have provided evidence for the therapeutic potential of bone marrow‐derived mononuclear cells (MNCs) in animal models of stroke, the mechanisms underlying their benefits remain largely unknown. We have determined the neuroprotective potential of MNCs in primary neuronal cultures exposed to various injuries in vitro. Cortical neurons in culture were exposed to oxygen‐glucose deprivation, hypoxia, or hydrogen peroxide, and cell death was assayed by MTT, caspase‐3 activation or TUNEL labelling at 24 hrs. Cultures were randomized to cotreatment with MNC‐derived supernatants or media before injury exposure. In separate experiments, macrophage or microglial cultures were exposed to lipopolypolysacharide (LPS) in the presence and absence of MNC‐derived supernatants. Neuronal cultures were then exposed to conditioned media derived from activated macrophages or microglia. Cytokines from the supernantants of MNC cultures exposed to normoxia or hypoxia were also estimated by enzyme‐linked immunosorbant assay (ELISA). MNC‐derived supernatants attenuated neuronal death induced by OGD, hypoxia, hydrogen peroxide, and conditioned macrophage/microglial media and contain a number of trophic factors, including interleukin‐10, insulin‐like growth factor‐1, vascular endothelial growth factor, and stromal cell‐derived factor‐1. MNCs provide broad neuroprotection against a variety of injuries relevant to stroke. © 2010 Wiley‐Liss, Inc.
Mitigation of alkaline stress by arbuscular mycorrhiza in zucchini plants grown under mineral and organic fertilization
Authors: Cardarelli Mariateresa , Rouphael Youssef , Rea Elvira , Colla Giuseppe
Published: July 2010

A greenhouse experiment was carried out during the spring–summer 2009 to test the hypotheses that: (1) arbuscular‐mycorrhizal (AM) inoculation with a biofertilizer containing Glomus intraradices gives an advantage to overcome alkalinity problems, (2) mineral fertilization is more detrimental to AM development than organic fertilization on an equivalent nutrient basis. Arbuscular mycorrhizal (AM) and non‐AM of zucchini (Cucurbita pepo L.) plants were grown in sand culture with two pH levels in the nutrient solution (6.0 or 8.1) and two fertilization regimes (organic or mineral). The high‐pH nutrient solution had the same basic composition as the low‐pH solution, plus an additional 10 mM NaHCO3 and 0.5 g L–1 CaCO3. Increasing the concentration of NaHCO3 from 0 to 10 mM in the nutrient solution significantly decreased yield, plant growth, SPAD index, net assimilation of CO2 (ACO2), N, P, Ca, Mg, Fe, Mn, and Zn concentration in leaf tissue. The +AM plants under alkaline conditions had higher total, marketable yield and total biomass compared to –AM plants. The higher yield and biomass production in +AM plants seems to be related to the capacity of maintaining higher SPAD index, net ACO2, and to a better nutritional status (high P, K, Fe, Mn, and Zn and low Na accumulation) in response to bicarbonate stress with respect to –AM plants. The percentage root colonization was significantly higher in organic‐fertilized (35.7%) than in mineral‐fertilized plants (11.7%). Even though the AM root colonization was higher in organic‐fertilized plants, the highest yield and biomass production were observed in mineral‐fertilized plants due to the better nutritional status (higher N, P, Ca, and Mg), higher leaf area, SPAD index, and ACO2.
Raman spectroscopic study of the uranyl titanate mineral brannerite (U,Ca,Y,Ce)2(Ti,Fe)2O6:effect of metamictisation
Authors: Frost Ray L. , Reddy B. Jagannadha
Published: July 2010

Raman spectra of the uranyl titanate mineral brannerite were analysed and related to the mineral structure. A comparison is made with the Raman spectra of uranyl oxyhydroxide hydrates. The observed bands are attributed to the TiO and (UO2)2+ stretching and bending vibrations, UOH bending vibrations, as well as H2O and (OH)− stretching, bending and libration modes. UO bond lengths in uranyls and OH···O bond lengths were calculated from the wavenumbers assigned to the stretching vibrations. Raman bands of brannerite are in harmony with those of the uranyl oxyhydroxides. The mineral brannerite is metamict, as is evidenced by the intensity of the UO stretching and bending modes being of lower intensity than expected and with bands that are significantly broader. Copyright © 2010 John Wiley & Sons, Ltd.
Effects of monoacylglycerols on the oxidative stability of olive oil
Authors: Gomes Tommaso , Caponio Francesco , Bruno Giuseppina , Summo Carmine , Paradiso Vito Michele
Published: July 2010

BACKGROUND: The study of pro‐ and anti‐oxidant compounds is important for their influence on the shelf‐life and nutritional value of food. The aim of this research was to evaluate the activity of monoacylglycerols (MAG), obtained by partial saponification of a purified olive oil, added in increasing amounts to the same oil and submitted to the Rancimat test and oven test at 60 °C. Besides routine analyses, high‐performance size exclusion chromatography analysis of polar compounds was performed.

RESULTS: The addition of MAG led in all cases to a significant slowdown of the oxidative processes. These trends were more evident as the oxidation went on. The purified oil added with 30 g kg−1 of MAG after 9 days of oven test at 60 °C presented a level of oxidative degradation significantly lower than the control after only 4 days.

CONCLUSION: The data showed a marked antioxidant effect of MAG in purified olive oil, contrary to what has been observed by other authors, who noticed either a pro‐oxidant or a non‐antioxidant activity of these compounds in soybean oil. A different behaviour of MAG during oxidation could depend on the different fatty acid composition of the oil matter they are added to. Copyright © 2010 Society of Chemical Industry
Effects of selected lactic acid bacteria on the characteristics of amaranth sourdough
Authors: Jekle Mario , Houben Andreas , Mitzscherling Martin , Becker Thomas
Published: July 2010

BACKGROUND: As the processing of amaranth in baked goods is challenging, the use of sourdough fermentation is a promising possibility to exploit the advantages of this raw material. In this study the fermentation properties of Lactobacillus plantarum, Lactobacillus paralimentarius and Lactobacillus helveticus in amaranth‐based sourdough were examined in order to validate them as starter cultures. pH, total titratable acidity (TTA) and lactic/acetic acid ratio of the sourdough and sensory properties of the resulting wheat bread were evaluated using fermentation temperatures of 30 and 35 °C.

RESULTS: While fermentation pH, TTA and lactic acid concentration showed small variations with the use of L. plantarum and L. paralimentarius, L. helveticus reached the most intensive acidification after initial adaptation to the substrate. Acetic acid production was independent of lactic acid metabolism. Furthermore, the lactic/acetic acid ratio exceeded recommendation by 10–35 times (fermentation quotient 25–82). Sensory evaluation showed no significant differences between the two fermentation temperatures but differences among the three micro‐organisms.

CONCLUSION: The results provide relevant information on the fermentation properties required of a customised starter for amaranth flour. Copyright © 2010 Society of Chemical Industry
Phenolic and carotenoid profiles of papaya fruit (Carica papaya L.) and their contents under low temperature storage
Authors: Rivera‐Pastrana Dulce M , Yahia Elhadi M , González‐Aguilar Gustavo A
Published: July 2010

BACKGROUND: Tropical fruits are rich in phenolic and carotenoid compounds, and these are associated with cultivar, pre‐ and postharvest handling factors. The aim of this work was to identify major phenolics and carotenoids in ‘Maradol’ papaya fruit and to investigate their response to storage temperature.

RESULTS: Ferulic acid, caffeic acid and rutin were identified in ‘Maradol’ papaya fruit exocarp as the most abundant phenolic compounds, and lycopene, β‐cryptoxanthin and β‐carotene were identified in mesocarp as the major carotenoids. Ranges of contents of ferulic acid (1.33–1.62 g kg−1 dry weight), caffeic acid (0.46–0.68 g kg−1 dw) and rutin (0.10–0.16 g kg−1 dw) were found in papaya fruit, which tend to decrease during ripening at 25 °C. Lycopene (0.0015 to 0.012 g kg−1 fresh weight) and β‐cryptoxanthin (0.0031 to 0.0080 g kg−1 fw) were found in fruits stored at 25 °C, which tend to increase during ripening. No significant differences in β‐carotene or rutin contents were observed in relation to storage temperature.

CONCLUSION: Phenolics and carotenoids of ‘Maradol’ papaya were influenced by postharvest storage temperature with exception of β‐carotene and rutin. Ripe papaya stored at 25 °C had more carotenoids than those stored at 1 °C. Low (chilling) temperature (1 °C) negatively affected the content of major carotenoids, except β‐carotene, but preserved or increased ferulic and caffeic acids levels, as compared to high (safe) temperature (25 °C). Copyright © 2010 Society of Chemical Industry
Morbidity results from the NSABP B‐32 trial comparing sentinel lymph node dissection versus axillary dissection
Authors: Ashikaga Takamaru , Krag David N. , Land Stephanie R. , Julian Thomas B. , Anderson Stewart J. , Brown Ann M. , Skelly Joan M. , Harlow Seth P. , Weaver Donald L. , Mamounas Eleftherios P. , Costantino Joseph P. , Wolmark Norman
Published: July 2010

Background and Objectives

Three year post‐surgical morbidity levels were compared between patients with negative sentinel lymph node dissection alone (SLND) and those with negative sentinel node dissection and negative axillary lymph node dissection (ALND) in the NSABP B‐32 trial.

Methods

A total of 1,975 ALND and 2,008 SLND node negative breast cancer patients had shoulder range of motion and arm volumes assessed along with self reports of arm tingling and numbness. Relative shoulder abduction deficits and relative arm volume differences between ipsilateral and contralateral arms were calculated.

Results

Shoulder abduction deficits ≥10% peaked at 1 week for the ALND (75%) and SLND (41%) groups. Arm volume differences ≥10% at 36 months were evident for the ALND (14%) and SLND (8%) groups. Numbness and tingling peaked at 6 months for the ALND (49%, 23%) and SLND (15%, 10%) groups. Logistic regression correlates of residual morbidity included treatment group, age, handedness, tumor size, systemic chemotherapy, and radiation to the axilla.

Conclusions

Although residual morbidity for both treatment groups was evident, the results of the NSABP B‐32 study indicate the superiority of the SLND compared to the ALND treatment approach relative to post‐surgical morbidity outcomes over a 3‐year follow‐up period. J. Surg. Oncol. 2010;102:111–118. © 2010 Wiley‐Liss, Inc.
Outcome in adult patients with head and neck sarcomas—a 10‐year analysis
Authors: Mücke Thomas , Mitchell David A. , Tannapfel Andrea , Hölzle Frank , Kesting Marco R. , Wolff Klaus‐Dietrich , Kolk Andreas , Kanatas Anastasios
Published: July 2010

Background and Objective

Sarcomas of the head and neck in adults are malignant tumors with many histological subtypes and sites of origin. The purpose of this study was to analyze the outcome of adult patients suffering from head and neck sarcomas and to identify any clinical and histological predictors of outcome.

Materials and Methods

The medical records of 74 patients treated during 1999–2008 were reviewed. All patients suffered from primary head and neck sarcomas.

Results

The mean survival of patients was 44.49 ± 32.25 months. The 2‐ and 5‐year overall survival rates were 83.78% and 60.81%. The nodal status (P = 0.032), tumor size (P < 0.0001), tumor location (P = 0.03), histological type (P = 0.002), the involvement of bone (P = 0.032), and age (P < 0.0001) were significant parameters influencing survival.

Conclusion

This study demonstrated a better than expected crude overall survival and a higher rate of recovery of involved regional lymph nodes with evidence of poorer outcome when cervical metastases are evident. It is suggested that this may reflect the impact of specialist head and neck surgical techniques (applicable to all head and neck malignancy) as well as the recognized need for specialization in pathology and nonsurgical oncology in the care of these patients. J. Surg. Oncol. 2010;102:170–174. © 2010 Wiley‐Liss, Inc.
Nature of torture, PTSD, and somatic symptoms among political ex‐prisoners
Authors: Punamäki Raija‐Leena , Qouta Samir R. , Sarraj Eyad El
Published: July 2010

The authors examined how different types of torture methods are associated with posttraumatic stress disorder (PTSD) and somatic symptoms among political ex‐prisoners. Participants were 275 Palestinian men who reported their experiences in detention and imprisonment, PTSD (the Harvard Trauma Questionnaire), and somatic symptoms. A principal component analysis revealed physical torture, psychological torture, sensory discomfort and deprivation, and beatings as dimensions of exposure to torture. Both physical and psychological torture methods were associated with increased PTSD symptoms, especially when combined. Psychological torture was also associated with increased somatic symptoms. The results are discussed in relation to their contribution to the current debate on the nature and definition of torture.
Design of Artificial Selenoenzymes Based on Macromolecular Scaffolds
Authors: Huang Xin , Yin Yanzhen , Liu Junqiu
Published: July 2010

The selenoenzyme glutathione peroxidase has received increased attention as one of the antioxidative enzymes exerting important biological roles in living bodies. Over the past decades, much effort has been invested to mimic its catalytic behavior for understanding enzymatic catalytic mechanisms and also for developing potential medicines. A great number of artificial GPxs, ranging from small molecular compounds to macromolecular ones, have been designed and prepared by combining the concept of recognition and catalysis using chemical, biological and supramolecular strategies. In this article, we specify the development of artificial GPxs based on macromolecules as scaffolds, and discuss the power of reduced models in studying the bio‐catalytic nature of selenoenzymes.

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The anti‐Specker property, positivity, and total boundedness
Authors: Bridges Douglas , Diener Hannes
Published: July 2010

Working within Bishop‐style constructive mathematics, we examine some of the consequences of the anti‐Specker property, known to be equivalent to a version of Brouwer's fan theorem. The work is a contribution to constructive reverse mathematics (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On some peculiar aspects of the constructive theory of point‐free spaces
Authors: Curi Giovanni
Published: July 2010

This paper presents several independence results concerning the topos‐valid and the intuitionistic (generalised) predicative theory of locales. In particular, certain consequences of the consistency of a general form of Troelstra's uniformity principle with constructive set theory and type theory are examined (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the Importance of Morphology Control in Polymer Solar Cells
Authors: van Bavel Svetlana , Veenstra Sjoerd , Loos Joachim
Published: July 2010

Nanostructured polymer‐based solar cells (PSCs) have emerged as a promising low‐cost alternative to conventional inorganic photovoltaic devices and are now a subject of intensive research both in academia and industry. For PSCs to become practical efficient devices, several issues should still be addressed, including further understanding of their operation and stability, which in turn are largely determined by the morphological organisation in the photoactive layer. The latter is typically a few hundred nanometres thick film and is a blend composed of two materials: the bulk heterojunction consisting of the electron donor and the electron acceptor. The main requirements for the morphology of efficient photoactive layers are nanoscale phase segregation for a high donor/acceptor interface area and hence efficient exciton dissociation, short and continuous percolation pathways of both components leading through the layer thickness to the corresponding electrodes for efficient charge transport and collection, and high crystallinity of both donor and acceptor materials for high charge mobility. In this paper, we review recent progress of our understanding on how the efficiency of a bulk heterojunction PSC largely depends on the local nanoscale volume organisation of the photoactive layer.

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Freezing of gait in Parkinson's disease: The impact of dual‐tasking and turning
Authors: Spildooren Joke , Vercruysse Sarah , Desloovere Kaat , Vandenberghe Wim , Kerckhofs Eric , Nieuwboer Alice
Published: July 2010

Background: Turning is the most important trigger for freezing of gait (FOG) in Parkinson's disease (PD), and dual‐tasking has been suggested to influence FOG as well. Objective: To understand the effects of dual tasking and turning on FOG. Methods: 14 Freezers and 14 non‐freezers matched for disease severity and 14 age‐matched controls were asked to turn 180° and 360° with and without a cognitive dual‐task during the off‐period of the medication cycle. Total number of steps, duration, cadence, freezing‐frequency, and secondary‐task performance were measured. Results: Seven freezers froze during the protocol. Freezing occurred in 37.5% of trials during 180° turning compared to 0% during straight‐line walking (X2 = 10.44, p < 0.01). The occurrence of FOG increased during 360° when also a dual‐task was added (X2 = 4.23, p = 0.04). Freezers took significantly more steps and were slower than controls in all conditions. The presence of a dual‐task increased these differences. Cadence increased significantly for freezers during 360° and 180° compared to straight‐line walking. In contrast, cadence was decreased during turning in controls and non‐freezers. During straight‐line walking, only freezers made errors in the secondary task. Controls increased their error‐rate during 180° turning, whereas freezers deteriorated their secondary task performance during 360°. Conclusions: 360° turning in combination with a dual‐task is the most important trigger for freezing. During turning, non‐freezers and controls decreased their cadence whereas freezers increased it, which may be related to FOG. Freezers adopted a posture second strategy in contrast to non‐freezers when confronted with a dual task. © 2010 Movement Disorder Society
An ultra‐wide stopband microstrip bandpass filter
Authors: Zheng Guangming , Lin Weigan
Published: July 2010

This article develops a novel microstrip bandpass filter with ultra‐wide stopband.With the assistance of open stubs and interdigital capacitors, a very wide stopband with a sufficient rejection level can be achieved easily. Detailed design and synthesis procedures are provided. Moreover, the electromagnetic simulator ansoft designer v3 is used, and the prototype of the bandpass filter is fabricated and measured. Good agreement between measured and theoretically predicted results demonstrates feasibility of the proposed filter. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2218–2221, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25426
Compact stub‐loaded meander‐line antenna for wireless USB dongle devices
Authors: Byul Kim Han , Cheol Hwang Keum , Bae Park Yong
Published: July 2010

A planar meander‐line monopole antenna was designed for wireless Universal Serial Bus (USB) dongle devices. The proposed antenna shows dual‐wideband resonant characteristics and supports the WiBro, Bluetooth, WLAN, WiMAX, and S‐DMB (Satellite Digital Multimedia Broadcast) services. The designed antenna measures 19 × 50 × 1 mm3, which is suitable for compact USB dongles. The measured 2:1 bandwidths of the voltage standing wave ratio are 18.1% (2.26–2.71 GHz) and 16.4% (5.09–6.0 GHz). The measured peak gain is 3.49 dBi, and efficiency is higher than 56%. The radiation patterns are also nearly omni‐directional. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2279–2282, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25430
Small‐size internal eight‐band LTE/WWAN mobile phone antenna with internal distributed LC matching circuit
Authors: Wong Kin‐Lu , Chen Wei‐Yu , Wu Chun‐Yih , Li Wei‐Yu
Published: July 2010

A coupled‐fed planar inverted‐F antenna (PIFA) to be mounted at the small no‐ground portion of the system circuit board of the mobile phone with a low profile of 10 mm to the system ground plane and a thin profile of 3 mm to the system circuit board is presented.The proposed small‐size PIFA is formed by a simple structure of two radiating strips of different lengths, both capacitively fed by a coupling feed and short circuited to the system ground plane by a shorting strip. The coupling feed and shorting strip together function as an internal distributed LC matching circuit, with the coupling feed as a capacitive element and the shorting strip as an inductive element. This internal distributed LC matching circuit has an equivalent layout as the conventional external high‐pass LC matching circuit with lumped elements; both are effective in tuning the antenna's lower band bandwidth. In addition, the antenna with the proposed internal distributed LC matching circuit, in this study, can lead to much widened bandwidths in both the antenna's lower and upper bands to cover the 698–960 and 1710–2690 MHz bands, respectively. That is, eight‐band LTE/WWAN operation can be achieved. Results of the proposed antenna with the internal distributed LC matching circuit are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2244–2250, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25431
New stubless compact low‐pass filter using lumped shunt capacitors and coupled slots
Authors: Abdel‐Rahman Adel
Published: July 2010

This article introduces an improved performance stubless low‐pass filter by using lumped capacitors as shunt capacitances elements.The filter has a cut off frequency of 4 GHz and a wide stopband up to more than 13 GHz with a rejection better than 26 dB. The measured insertion loss of the filter within the passband is less than 0.3 dB. The filter has a length of just 6.5 mm. The experimental results agree well with the predicted ones. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2209–2212, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25434
Walking intrusion signal recognition method based on gait characteristic for fiber fence system
Authors: Fang Nian , Wang Lutang , Jia Dongjian , Shan Chao , Huang Zhaoming
Published: July 2010

A recognition method based on the gait characteristic for walking intrusion signal of a fiber fence system is presented, which can reduce the rate of false alarm. The gait characteristic of human is mainly embodied in an intermittent and quasi‐periodic contact with the floor when he walks. It can be expressed in terms of step period and foot‐strike time. They are, on average, about 0.63 s and 0.2 s for a normal walker in the nature state, respectively. According this intermittent and quasi‐periodic feature and local characteristic gait times imbedded in a fiber fence system output waveform, a disturbance source can be adjudged as a human intrusion, not as an animal or other random one. Two types of experimental results show that the proposed method is effective and universal for different systems and races. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2381–2384, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25437
Band‐pass filters using high‐permittivity ceramics substrate
Authors: Huang Cheng‐Liang , Tasi Shin‐Tung , Chen Yuan‐Bin
Published: July 2010

The miniaturization of ring band‐pass filters by employing high‐permittivity ceramic substrates (with respective dielectric constants of 9.7 and 23.5) are investigated. Microwave dielectric ceramics with high‐permittivity are commonly applied in several microwave communication components. With the advantages of compact size, high‐permittivity ceramics can be used as the substrate for band‐pass filters. Moreover, the fundamental characteristics of newly developed compact ring resonators have also been described and applied to the design of band‐pass filters. In this article, the designed ring resonators structures are simulated using an HFSS simulator. The responses of the fabricated band‐pass filters using Al2O3 (εr = 9.7, tanδ = 0.0001) and 0.875Mg0.95Zn0.05TiO3‐0.125Ca0.8Sm0.4/3TiO3 (εr = 23.5, tanδ = 0.000083) ceramic substrates are designed at the center frequency of 2.4 GHz. This compact size, low loss band‐pass filter should be useful in many wireless communication systems. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2344–2347, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25439
Dielectric properties characterization of high dielectric constant thick films
Authors: Demenicis Luciene S. , Marulanda José Ignacio , Lima Rodolfo A. A. , Carvalho Maria Cristina R.
Published: July 2010

A technique for the characterization of microwave dielectric properties of high dielectric constant thick films at room temperature is proposed, using multilayered coplanar waveguide transmission lines with high dielectric constant thick films deposited over the lines.Besides the simplicity, the technique allows the characterization of the films under similar conditions to those in which they will operate as compact devices in multilayered configurations. Time domain analysis and experimental results for 61‐micron thick Barium Titanate films have confirmed the relative dielectric constant and loss tangent values (respectively, 100 and 0.3) predicted by the frequency domain characterization proposed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2339–2344, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25440
Bandwidth enhancement of a planar sleeve monopole antenna for wireless communication applications
Authors: Zuo Shaoli , Zhang Zhiya , Yin Yingzeng
Published: July 2010

A planar sleeve monopole antenna for bandwidth enhancement is proposed and experimentally studied.By embedding a concavity sleeve in the ground plane and etching two pairs of L‐shaped slots on a printed circuit board, it is found that the operating bandwidth can be significantly enhanced and the impedance bandwidth could cover the GSM, DCS, PCS, ISM/Bluetooth (2400–2480 MHz), WLAN (2400–2484 MHz), and WiMAX (2500–2690 MHz) bands. By using a capacity load on the top of the antenna, the dimension of the antenna is reduced largely. The proposed antenna has good omnidirectional radiation characteristics and achieves gains to be 2.6, 3.2, and 3.5 dBi at 900, 1800, and 2450 MHz, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2235–2238, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25445
A compact pentagonal monopole antenna for portable UWB systems
Authors: Thomas Paulbert , Gopikrishna M. , Aanandan C. K. , Mohanan P. , Vasudevan K.
Published: July 2010

Design of a compact microstrip‐fed ultra‐wideband antenna suitable for USB dongle and other such space constraint applications is presented. The structure consists of a pentagonal monopole element and a modified ground plane that gives an impedance bandwidth from 2.8 to 12 GHz. Radiation patterns are stable and omni‐directional throughout the band with an average gain of 2.84 dBi. The antenna occupies only 11 × 30 mm2 on FR4 substrate with permittivity 4.4. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2390–2393, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25449
Circularly polarized space‐fed microstrip antenna arrays
Authors: Bhide Rahul , Kumar Girish
Published: July 2010

A high‐gain circularly polarized microstrip antenna array is proposed using space‐fed configuration. In planar arrays, the design of feed network to generate circular polarization becomes extremely complex. The proposed configuration eliminates the feed network, which gives high efficiency and gain. Simulated and measured results are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2221–2223, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25451
DUAL‐BAND antenna for WLAN/UWB applications
Authors: Park Sang Yong , Jeong Oh Seon , Park Jong Kweon
Published: July 2010

In this article, we have proposed a dual‐band (WLAN/UWB) antenna with open stub for WLAN/UWB applications. The designed dual‐band antenna consists of a rectangular radiating patch, open stub, three steps for impedance matching, and coplanar waveguide feeding. The proposed antenna is fabricated and measured. Parametric studies and radiation characteristics for the designed antenna were presented. The designed antenna has the characteristics of wide bandwidth and negligible dispersion over the UWB frequency band and omnidirectional characteristics in the WLAN band. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2188–2191, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25452
Compact wide upper‐stopband BPF using open stub loaded dual‐mode resonator
Authors: Deng Hong‐Wei , Zhao Yong‐Jiu , Zhang Xue‐Shun , Zhang Lu , Gao Si‐Ping
Published: July 2010

A novel compact bandpass filter (BPF) with good in band and wide upper‐stopband performances is realized using open stub loaded dual‐mode resonator.The resonator generates two operating modes in the desired band and the even‐mode resonance frequency can be flexibly controlled by the disc‐shaped open stub at central plane, whereas the odd‐mode one is fixed. By simply adjusting the dimension of the disc‐shaped open stub, the even resonant mode falls down and works together with the odd mode to form a BPF. Two other pairs of open stubs are mainly applied to suppress the high harmonic resonant modes and obtain good match, respectively. Experimental results of the fabricated filter show good agreement with the simulated results. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2185–2188, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25453
On the comparison between multiple‐region and dual‐grid finite‐difference time‐domain methods for the analysis of antenna arrays
Authors: Pascaud Romain , Gillard Raphaël , Loison Renaud
Published: July 2010

A comparison between the multiple‐region (MR) and dual‐grid (DG) finite‐difference time‐domain (FDTD) methods for the analysis of antenna arrays is presented.The application of both methods shows that the DG‐FDTD method is more accurate when computing the mutual coupling between antennas. Besides, it exhibits multi‐surface capabilities that make possible the fast and accurate analysis of antenna arrays, including mutual coupling and edge effects. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2316–2319, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25456
Negative refraction imaging by three‐dimensional metamaterial at microwave frequencies
Authors: Zhao Wangshi , Lu Zhaolin
Published: July 2010

We experimentally demonstrate negative refraction imaging at microwave frequencies by a three‐dimensional (3D) metamaterial with simple cubic unit structure, which is fabricated based on the electronic textile technology.A four‐layer metamaterial sample was tested in a series of experiments. The experimental result of the characteristic plasma frequency of the metamaterial was in good agreement with the theoretical result. The fabrication approach for 3D metamaterial may find many novel applications at microwave frequencies. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2253–2256, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25459
Bandwidth enhancement of a coplanar waveguide‐fed asymmetrical slot antenna with a rectangular patch
Authors: Fan Shou‐Tao , Yin Ying‐Zeng , Kang Le , Wei Shi‐Ju , Wang Yao‐Zhao , Song Kun
Published: July 2010

A coplanar waveguide‐fed asymmetrical slot antenna with a rectangular patch for bandwidth enhancement is demonstrated.By attaching a rectangular patch to the monopole radiating element, a good performance of bandwidth enhancement for the antenna is achieved. From simulational and experimental results, the enhanced impedance bandwidth of the proposed antenna, defined by −10 dB return loss, can reach 13.1 GHz, from 2.4 to 15.5 GHz, or about 146% with the center frequency 8.95 GHz, which makes it an excellent candidate for the ultra wideband (UWB, 3.1–10.6 GHz) applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2259–2261, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25476
Broadband, high‐gain complementary‐symmetry microstrip array antenna
Authors: Sameena N. M. , Konda R. B. , Mulgi S. N.
Published: July 2010

A novel complementary‐symmetry microstrip array antenna is presented for broadband operation. The maximum impedance bandwidth of 132.12% and high gain of 10.08 dB is achieved. The radiation patterns are found broadsided across the entire operating band. The design concept of the antenna is described and the experimental results are discussed. The proposed antenna may find applications for the systems operating from C to Ku (3.9 to 18 GHz) band of frequencies. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2256–2258, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25477
Compact ultra‐wideband CPW‐FED printed semicircular slot antenna
Authors: Ranga Y. , Esselle Karu P. , Weily A. R.
Published: July 2010

A new compact configuration of a printed CPW‐fed semicircular slot antenna with a CPW‐to‐CPW step transition is presented. Its bandwidth is enhanced for ultra‐wideband (UWB) operation by combining linear and stepped CPW‐to‐CPW transitions along the feed line. Its measured 10 dB return loss bandwidth is 3.1–13.8 GHz (126%). This, together with its nearly constant measured gain of 3.5 dBi ± 1 dB from 3 to 10 GHz, makes it suitable for UWB applications. Details of the proposed antenna are described, and both theoretical and experimental results are presented. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2367–2372, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25481
Compact waveguide bandpass and bandstop filters using negative index material concepts
Authors: Lam Tai , Greegor Robert B. , Parazzoli Claudio G. , Tanielian Minas H.
Published: July 2010

Split ring resonators (SRR) and complementary SRRs (CSRR) are used to design bandstop and bandpass filters in waveguides. These filters are more compact than existing waveguide filters and have no appreciable weight of their own. They have been fabricated and tested showing good agreement between simulations and experiments. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2336–2339, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25482
Millimeter‐wave power module combiner junction for high resolution advanced radar and communications
Authors: Spears M. , Van Gorden C. , Wehnes D. , Song H.
Published: July 2010

Power combiner junctions based on hybrid waveguide structures were designed, fabricated, and characterized for advanced radar and communications millimeter‐wave power modules.Various structures of the four port combiners were investigated at Ka‐ and V‐bands. The measurement results were compared with the three‐dimensional full wave finite element method solutions. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2227–2231, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25488
Balanced SSFP transient imaging using variable flip angles for a predefined signal profile
Authors: Worters Pauline W. , Hargreaves Brian A.
Published: July 2010

Variable flip angles are used in steady‐state free precession (SSFP) acquisitions (e.g., time‐of‐flight) but to a lesser extent than in spin echo acquisitions. In balanced steady‐state free precession, imaging is often assumed to occur during the steady state, which has been well described in the literature. However, in many cases, imaging occurs during the transient stage, and the use of variable flip angles can improve signal and thus image quality. Here, we present the calculation of flip angles in transient balanced steady‐state free precession to generate a predefined signal profile. The signal profile was iteratively optimized to maximize the integral of the signal versus time curve. The key contribution of this work is the formulation of the flip angle as a deterministic function of the preceding and desired magnetization. Catalyzation schemes, e.g., Kaiser‐windowed ramp, can be combined with variable flip angles balanced steady‐state free precession to reduce signal oscillations. A uniform signal profile was used as an example to demonstrate the variable flip angle algorithm. Accuracy of the algorithm and Bloch simulations were verified with MRI phantom acquisitions. Renal angiograms were acquired using an inflow‐based balanced steady‐state free precession MR angiography technique; improved small‐vessel depiction was observed in volunteer examinations. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Fast 3D chemical exchange saturation transfer (CEST) imaging of the human brain
Authors: Zhu He , Jones Craig K. , van Zijl Peter C. M. , Barker Peter B. , Zhou Jinyuan
Published: July 2010

Chemical exchange saturation transfer magnetic resonance imaging can detect low‐concentration compounds with exchangeable protons through saturation transfer to water. This technique is generally slow, as it requires acquisition of saturation images at multiple frequencies. In addition, multislice imaging is complicated by saturation effects differing from slice to slice because of relaxation losses. In this study, a fast three‐dimensional chemical exchange saturation transfer imaging sequence is presented that allows whole‐brain coverage for a frequency‐dependent saturation spectrum (z‐spectrum, 26 frequencies) in less than 10 min. The approach employs a three‐dimensional gradient‐ and spin‐echo readout using a prototype 32‐channel phased‐array coil, combined with two‐dimensional sensitivity encoding accelerations. Results from a homogenous protein‐containing phantom at 3T show that the sequence produced a uniform contrast across all slices. To show translational feasibility, scans were also performed on five healthy human subjects. Results for chemical exchange saturation transfer images at 3.5 ppm downfield of the water resonance, so‐called amide proton transfer images, show that lipid signals are sufficiently suppressed and artifacts caused by B0 inhomogeneity can be removed in postprocessing. The scan time and image quality of these in vivo results show that three‐dimensional chemical exchange saturation trasfer MRI using gradient‐ and spin‐echo acquisition is feasible for whole‐brain chemical exchange saturation transfer studies at 3T in a clinical time frame. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Quarzmikrowaage für elektrochemische Anwendungen
Authors: Wudy Franz , Bublitz Dirk
Published: July 2010

Franz Wudy, Dirk Bublitz

Impedanzspektroskopisch vermessen, lassen sich Schwingquarze auch in flüssigen Medien verwenden und detektieren Masseänderungen im Nanogrammbereich.
Uran und Fluor – zwei eng verwobene Elemente
Authors: Kraus Florian
Published: July 2010

Florian Kraus

Uran und Fluor sind heute zwei intensiv genutzte Elemente. Seit mehr als 50 Jahren bildet UF6

das zentrale Element bei der Isotopentrennung des Urans. Gegenwärtig lagern große Mengen abgereichertes UF6 ungenutzt − eine Chance für die moderne Fluorchemie.
”Free – that is my style”
Authors: Remenyi Christian
Published: July 2010

Total synthesis and differences between European and American research culture:

Nachrichten aus der Chemie talks with Kyriacos C. Nicolaou.
Wissen vermehren – Naturwissenschaftler vernetzen
Authors: Hofmayer Sören
Published: July 2010

Sören Hofmayer

Weil kaum ein wissenschaftlicher Fortschritt ohne das Wissen anderer möglich ist, ist eine vernetzte Wissenschaftswelt nützlich. Die Internetplattform Researchgate verbindet Forscher weltweit.
Neues aus dem Reich der Viren
Authors: Gross Michael
Published: July 2010

Michael Groß

Viren spielen eine Rolle für die Nahrungsketten in der Tiefsee, und sie können andere Viren befallen: Das waren vor kurzem zwei Entdeckungen in schneller Folge. Außerdem lässt sich gegen von Viren erzeugte Krankheiten wie Grippe wohl bald effektiver vorbeugen.
An Wert verloren – Chancen gewonnen
Authors: Hübel Marcus
Published: July 2010

Marcus Hübel

Die chemische Industrie spürt die sinkende Nachfrage in Märkten wie der Automobil‐, Bau‐ und Textilindustrie − nicht nur in den USA. Die Chemiebranche erwartet ein durch die globale Finanzkrise verschlechtertes Geschäftsumfeld.
Anisotropic viscoplastic modeling of rate‐dependent behavior of clay
Authors: Ou C. Y. , Liu C. C. , Chin C. K.
Published: July 2010

The objective of this study is to derive an effective stress‐based constitutive law capable of predicting rate‐dependent stress–strain, stress path and undrained shear strength and creep behavior. The flow rule used in the MIT‐E3 model and viscoplasticity theory is employed in the derivation. The model adopts the yield surface capable of representing the yield behavior of the Taipei silty clay and assumes that it is initially symmetric about the K0‐line. A method is then developed to compute the gyration and expansion of the loading surface to simulate the anisotropic behavior due to the principal stress rotation after shear. There are 11 parameters required for the model to describe the soil behavior and six of them are exactly the same as those used in the Modified Cam‐clay model. The five additional parameters can be obtained by parametric studies or conventional soil tests, such as consolidation tests, triaxial compression and extension tests. Finally, verification of the model for the anisotropic behavior, creep behavior and the rate‐dependent undrained stress–strain and shear strength of the Taipei silty clay is conducted. Copyright © 2010 John Wiley & Sons, Ltd.
A thermo‐hydro‐mechanical model for unsaturated soils based on the effective stress concept
Authors: Dumont Matthieu , Taibi Said , Fleureau Jean‐Marie , Abou‐Bekr Nabil , Saouab Abdelghani
Published: July 2010

A simple thermo‐hydro‐mechanical (THM) constitutive model for unsaturated soils is described. The effective stress concept is extended to unsaturated soils with the introduction of a capillary stress. This capillary stress is based on a microstructural model and calculated from attraction forces due to water menisci. The effect of desaturation and the thermal softening phenomenon are modelled with a minimal number of material parameters and based on existing models. THM process is qualitatively and quantitatively modelled by using experimental data and previous work to show the application of the model, including a drying path under mechanical stress with transition between saturated and unsaturated states, a heating path under constant suction and a deviatoric path with imposed suction and temperature. The results show that the present model can simulate the THM behaviour in unsaturated soils in a satisfactory way. Copyright © 2010 John Wiley & Sons, Ltd.
Study of the effect of organic clay on the shear‐induced crystallization of high‐density polyethylene through dynamic‐packing injection molding
Authors: Deng Cong , Gao Xueqin , Chen Zhanchun , Xue Shan , Shen Kaizhi
Published: July 2010

Organic nanoparticles as heterogeneous nucleators have a great effect on the crystallization of polymer matrices in nanocomposite systems, and the effect will be enhanced under shear flow. A home‐made dynamic‐packing injection molding (DPIM) device was developed to explore the effect of organic clay on the shear‐induced crystallization of high‐density polyethylene (HDPE). Differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD) and scanning electron microscopy (SEM) were used to characterize the flow‐induced crystalline structure of HDPE/clay nanocomposite injection moldings. It was found that higher crystallinity and thicker crystal planes which contribute to the improvement of mechanical properties were achieved in HDPE/clay nanocomposite samples prepared by DPIM. DSC results clearly showed that an increase of about 16% in crystallinity was achieved in dynamic HDPE/clay nanocomposite samples compared with traditional unfilled HDPE samples. WAXD confirmed that dynamic HDPE/clay nanocomposite samples had maximum crystal sizes at the (110) and (200) planes of 335 and 305 Å, respectively. SEM images indicated that the arrangement of crystalline structures in dynamic HDPE/clay samples was altered slightly compared with unfilled HDPE samples prepared using the same processing parameters. The results showed that organic clay was beneficial for increasing crystallinity and crystal size in the HDPE/clay nanocomposite system under shear flow. Meanwhile the arrangement of crystalline structures was insignificantly affected by the organic clay, and the preferred regular arrangement of lamellae could still be formed in the dynamic HDPE/clay nanocomposite system. Copyright © 2010 Society of Chemical Industry