bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal trends of hydro‐climatic variables and runoff response to climatic variability and vegetation changes in the Yiluo River basin, China
Authors: Liu Qiang , Yang Zhifeng , Cui Baoshan , Sun Tao
Published: August 2009

The Yiluo River is the largest tributary for the middle and lower reaches of the Yellow River below Sanmenxia Dam. Changes of the hydrological processes in the Yiluo River basin, influenced by the climatic variability and human activities, can directly affect ecological integrity in the lower reach of the Yellow River. Understanding the impact of the climatic variability and human activities on the hydrological processes in the Yiluo River basin is especially important to maintain the ecosystem integrity and sustain the society development in the lower reach of the Yellow River basin. In this study, the temporal trends of annual precipitation, air temperature, reference evapotranspiration (ET0) and runoff during 1961–2000 in the Yiluo River basin were explored by the Mann‐Kendall method (M‐K method), Yamamoto method and linear fitted model. The impacts of the climatic variability and vegetation changes on the annual runoff were discussed by the empirical model and simple water balance model and their contribution to change of annual runoff have been estimated. Results indicated that (i) significant upwards trend for air temperature and significant downwards trend both for precipitation and ET0 were detected by the M‐K method at 95% confidence level. And the consistent trends were obtained by the linear fitted model; (ii) the abrupt change started from 1987 detected by the M‐K method and Yamamoto method, and so the annual runoff during 1961–2000 was divided into two periods: baseline period (1961–1986) and changeable period (1987–2000); and (iii) the vegetation changes were the main cause for change of annual runoff from baseline period to changeable period, and climatic variability contributed a little to the change of annual runoff of the Yiluo River. Copyright © 2009 John Wiley & Sons, Ltd.
Spatial, inter and intra‐annual variability of the Upper Blue Nile Basin rainfall
Authors: Abtew Wossenu , Melesse Assefa M. , Dessalegne Tibebe
Published: August 2009

In this study, monthly and annual Upper Blue Nile Basin rainfall data were analyzed to learn the rainfall statistics and its temporal and spatial distribution. Frequency analysis and spatial characterization of rainfall in the Upper Blue Nile Basin are presented. Frequency analysis was performed on monthly basin rainfall. Monthly basin average rainfall data were computed from a network of 32 gauges with varying lengths of records. Monthly rainfall probability distribution varies from month to month fitting Gamma‐2, Normal, Weibull and Log‐Normal distributions. The January, July, October and November basin rainfall fit the Gamma‐2 probability distribution. The February, June and December ones fit Weibull distribution. The March, April, May and August rainfall fit Normal distribution. The September rainfall fits Log‐Normal distribution. Upper Blue Nile Basin is relatively wet with a mean annual rainfall of 1423 mm (1960–2002) with a standard deviation of 125 mm. The annual rainfall has a Normal probability distribution. The 100‐year‐drought basin annual rainfall is 1132 mm and the 100‐year‐wet basin annual rainfall is 1745 mm. The dry season is from November through April. The wet season runs from June through September with 74% of the annual rainfall. October and May are transition months. Monthly and annual rainfalls for return periods 2‐, 5‐, 10‐, 25‐, 50‐ and 100‐year dry and wet patterns are presented. Spatial distribution of annual rainfall over the basin is mapped and shows high variation with the southern tip receiving as high as 2049 mm and the northeastern tip as low as 794 mm annual average rainfall. Copyright © 2009 John Wiley & Sons, Ltd.
A network of knowledge on applying an indicator‐based methodology for minimizing flood vulnerability
Authors: Balica Stefania , Wright Nigel G.
Published: August 2009

Flood vulnerability assessment plays a key role in the area of risk management. Therefore, techniques that make this assessment more straightforward and at the same time improve the results are important. In this briefing, we present an automated calculation of a flood vulnerability index implemented through a web management interface (PHP) that enhances the ability of decision makers to strategically guide investment. To test the applicability of this methodology using this website, many case studies are required in order to cover the full range of cases in terms of scale such as river basin, subcatchment and urban area. This requires prompt solutions with large amounts of data and this has led to the development of this automated tool to help organize, monitor, process and compare the data of different case studies. The authors aim to create a network of knowledge between different institutions and universities in which this methodology is used. It is also hoped to encourage collaboration between the members of the network on managing flood vulnerability information and also promoting further studies on flood risk assessment at all scales. Copyright © 2009 John Wiley & Sons, Ltd.
A new multiparameter assay to assess HPV 16/18, viral load and physical status together with gain of telomerase genes in HPV‐related cancers
Authors: Theelen Wendy , Reijans Martin , Simons Guus , Ramaekers Frans C.S. , Speel Ernst‐Jan M. , Hopman Anton H.N.
Published: August 2009

Oncogenic human papillomavirus (HPV) is the most important risk factor for cancer of the uterine cervix and a subgroup of head and neck cancers. Viral load has been associated with persistence of infection, whereas integration of HPV into the host cell genome is associated with transition to invasive disease. Viral integration is frequently correlated with loss of viral E2 and gain of the telomerase‐related genes TERC and TERT. The objective of this study was to develop a rapid and sensitive multiplex ligation‐dependent probe amplification (MLPA) assay for the simultaneous analysis of viral load, integration and copy number gain of TERC and TERT in HPV16/18‐associated lesions. The performance of the assay was tested for HPV vs. human gene copy number ratios ranging from 0.1 to 100 and for percentages of integration ranging from 0 to 100%. The model systems used include plasmid mixtures and the HPV‐positive cell lines SiHa, HeLa and CaSki described to contain a range of 2–600 viral copies per cell. In samples with low‐viral load, viral integration can be reliably determined when more than 30% of the virus is integrated. Gain of the telomerase‐related genes in the cell lines as determined by our MLPA assay was in accordance with data reported in the literature. Our study demonstrates that within a single MLPA‐reaction viral type, load, integration and gain of TERC and TERT can be reliably determined, which will improve risk assessment for patients suspected for HPV infection.
Satellite image segmentation using hybrid variable genetic algorithm
Authors: Awad Mohamad M. , Chehdi Kacem
Published: August 2009

Image segmentation is an important task in image processing and analysis. Many segmentation methods have been used to segment satellite images. The success of each method depends on the characteristics of the acquired image such as resolution limitations and on the percentage of imperfections in the process of image acquisition due to noise. Many of these methods require a priori knowledge which is difficult to obtain. Some of them are parametric statistical methods that use many parameters which are dependent on image property. In this article, a new unsupervised nonparametric method is developed to segment satellite images into homogeneous regions without any a priori knowledge. The new method is called hybrid variable genetic algorithm (HVGA). The variability is found in the variable number of cluster centers and in the changeable mutation rate. In addition, this new method uses different heuristic processes to increase the efficiency of genetic algorithm in avoiding local optimal solutions. Experiments performed on two different satellite images (Landsat and Spot) proved the high accuracy and efficiency of HVGA compared with another two unsupervised and nonparametric segmentation methods genetic algorithm (GA) and self‐organizing map (SOM). The verification of the results included stability and accuracy measurements using an evaluation method implemented from the functional model (FM) and field surveys. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 199–207, 2009
A novel porous bioceramics scaffold by accumulating hydroxyapatite spherules for large bone tissue engineering in vivo. I. Preparation and characterization of scaffold
Authors: Peng Qian , Jiang Faxing , Huang Peng , Zhou Shaobing , Weng Jie , Bao Chongyun , Zhang Cong , Yu Haiyang
Published: August 2009

A novel scaffold with large dimension of 3–4 cm in length and 1–1.5 cm in diameter was designed and fabricated for engineering large bone tissue in vivo. The scaffold was constructed by filling hydroxyapatite (HA) spherules into a porous HA tube. The HA spherules were prepared by chitin sol emulsification in oil and gelation in situ, and their sizes can be controlled by parameters such as stirring rate and oil temperature. Accumulation of the HA spherules formed the interconnected pores in the scaffold, and the porosity and microstructure of the scaffold can be controlled by varying the size and miroporous structure of the HA spherules. Porous HA tube coated with a thin layer of poly(L‐lactic acid) (PLA) held the HA spherules together and provided the initial strength of scaffolds. HA spherules can be easily compounded with biological substance, such as comminuted bone granules, before being filled into the HA tubes. A pilot study is underway to use the hybrid scaffolds at different sites such as muscle, peritoneum, and bone side. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Characterization of the in vitro macrophage response and in vivo host response to poly(ethylene glycol)‐based hydrogels
Authors: Lynn Aaron D. , Kyriakides Themis R. , Bryant Stephanie J.
Published: August 2009

Photopolymerizable poly(ethylene glycol) (PEG)‐ based hydrogels have great potential as in vivo cell delivery vehicles for tissue engineering. However, their success in vivo will be dependent on the host response. The objectives for this study were to explore the in vivo host response and in vitro macrophage response to commonly used PEG‐based hydrogels, PEG and PEG containing RGD. Acellular hydrogels were implanted subcutaneously into c57bl/6 mice and the foreign body response (FBR) was compared to medical grade silicone. Our findings demonstrated PEG‐RGD hydrogels resulted in a FBR similar to silicone, while PEG‐only hydrogels resulted in a robust inflammatory reaction characterized by a thick layer of macrophages at the material surface with evidence of gel degradation. In vitro, bone marrow‐derived primary macrophages adhered well and similarly to PEG‐based hydrogels, silicone, and tissue culture polystyrene when cultured for 4 days. Significantly higher gene expressions of the proinflammatory cytokines, TNF‐α and Il‐1β, were found in macrophages seeded onto PEG compared to PEG‐RGD and silicone at 1 and 2 days. PEG hydrogels were also shown to be susceptible to oxidative biodegradation. Our findings indicate that PEG‐only hydrogels are proinflammatory while RGD attenuates this negative reaction leading to a moderate FBR. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
Biomineralization of calcium phosphate on human hair protein film and formation of a novel hydroxyapatite–protein composite material
Authors: Fujii Toshihiro , Tanaka Teppei , Ohkawa Kousaku
Published: August 2009

Human hair protein can be used not only as a totally biodegradable material but also as a “self‐originated” material, which may avoid an undesirable immune reaction, if it has been prepared from a certain individual and implanted into the same person. In this study, a novel organic–inorganic composite, which contains human hair proteins and hydroxyapatite, was investigated as biomineral‐scaffolding materials. The human hair protein was extracted by our original “Shindai method” (Nakamura et al., Biol Pharm Bull 2002;25:569–572; Fujii et al., Biol Pharm Bull 2004;27:89–93). The extracts were exposed to CaCl2 solution for fabrication into flat films, which mainly consisted of α‐keratin. After washing with distilled water, ∼3 Ca2+ ions per 1 keratin molecule bound to the film. The Ca2+‐binding was slightly sensitive to the ionic strengths, and only Mg2+ inhibited binding of Ca2+. A composite of the human hair protein and calcium phosphate was prepared via alternate soaking processes using CaCl2 and Na2HPO4 solutions. As the soaking cycle proceeded, the film weight increased and its color became white, indicating successful deposition of calcium phosphate. The diameters of deposited calcium phosphate particles were about 2–4 μm. The proteins were not solubilized and degraded during the soaking processes. FTIR and WAXD analyses indicated that calcium phosphate was first deposited as amorphous, then transformed into crystalline monohydrogen calcium phosphate during the earlier soaking cycle, and, via octacalcium phosphate, finally converted into hydroxyapatite after 20 cycles. The present human hair protein/hydroxyapatite composite film is a “self‐originated” and also an intact proteinaceous material without chemical modification, and thus, a promising material for hard tissue engineering. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Cord blood for tissue regeneration
Authors: Buchheiser Anja , Liedtke Stefanie , Looijenga Leendert H.J. , Kögler Gesine
Published: August 2009

Umbilical cord blood (CB) has become a commonly accepted source of hematopoietic stem cells for transplantation in children and adults. It is readily available and outperforms bone marrow (BM) as well as peripheral blood stem cells in terms of tolerance for HLA‐mismatches between donor and recipient and its decreased graft‐versus‐host disease. Clinical use has been expanded from hematological malignancies to various areas such as treatment of metabolic genetic disorders or to induce angiogenesis. For the last years CB has been under intense experimental investigation in in vitro differentiation models as well as in preclinical animal models. Since CB‐derived stem cells offer multiple advantages over adult stem cells from other sources like BM, CB may provide a future source of stem cells for tissue repair and regeneration. To facilitate the use of CB‐derived stem cells in clinical scenarios, the biology of these cells needs to be further explored in detail particularly with regard to the fact that different non‐hematopoietic stem cell populations occur within CB. Here we explore the most consistent and the most contradictory data referring to the differentiation potential of CB‐derived stem cells and give an outlook on their potential clinical value including and possible reprogramming into IPS cells. J. Cell. Biochem. 108: 762–768, 2009. © 2009 Wiley‐Liss, Inc.
Embeddings of Un(q2) and symmetric strongly regular graphs
Authors: Cossidente Antonio
Published: August 2009

In the geometric setting of the embedding of the unitary group Un(q2) inside an orthogonal or a symplectic group over the subfield GF(q) of GF(q2), q odd, we show the existence of infinite families of transitive two‐character sets with respect to hyperplanes that in turn define new symmetric strongly regular graphs and two‐weight codes. © 2009 Wiley Periodicals, Inc. J Combin Designs 18: 248–253, 2010
Large Cayley graphs and vertex‐transitive non‐Cayley graphs of given degree and diameter
Authors: Macbeth Heather , Šiagiová Jana , Širáň Jozef , Vetrík Tomáš
Published: August 2009

For any d⩾5 and k⩾3 we construct a family of Cayley graphs of degree d, diameter k, and order at least k((d−3)/3)k. By comparison with other available results in this area we show that our family gives the largest currently known Cayley graphs for a wide range of sufficiently large degrees and diameters. © 2009 Wiley Periodicals, Inc. J Graph Theory 64: 87–98, 2010
Biclique graphs and biclique matrices
Authors: Groshaus Marina , Szwarcfiter Jayme L.
Published: August 2009

A biclique of a graph G is a maximal induced complete bipartite subgraph of G. Given a graph G, the biclique matrix of G is a {0,1,−1} matrix having one row for each biclique and one column for each vertex of G, and such that a pair of 1, −1 entries in a same row corresponds exactly to adjacent vertices in the corresponding biclique. We describe a characterization of biclique matrices, in similar terms as those employed in Gilmore's characterization of clique matrices. On the other hand, the biclique graph of a graph is the intersection graph of the bicliques of G. Using the concept of biclique matrices, we describe a Krausz‐type characterization of biclique graphs. Finally, we show that every induced P3 of a biclique graph must be included in a diamond or in a 3‐fan and we also characterize biclique graphs of bipartite graphs. © 2009 Wiley Periodicals, Inc. J Graph Theory 63: 1–16, 2010
Characterizing 3‐connected planar graphs and graphic matroids
Authors: Lemos Manoel , Reid Talmage James , Wu Haidong
Published: August 2009

A well‐known result of Tutte states that a 3‐connected graph G is planar if and only if every edge of G is contained in exactly two induced non‐separating circuits. Bixby and Cunningham generalized Tutte's result to binary matroids. We generalize both of these results and give new characterizations of both 3‐connected planar graphs and 3‐connected graphic matroids. Our main result determines when a natural necessary condition for a binary matroid to be graphic is also sufficient. © 2009 Wiley Periodicals, Inc. J Graph Theory 64: 165–174, 2010
A facile route to the synthesis of 1,4‐pyranonaphthoquinone derivatives under microwave irradiation without catalyst
Authors: Wang Xing‐Han , Zhang Xiao‐Hong , Tu Shu‐Jiang , Shi Feng , Zou Xiang , Yan Shu , Han Zheng‐Guo , Hao Wen‐Juan , Cao Xu‐Dong , Wu Shan‐Shan
Published: August 2009

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A series of 1,4‐pyranonaphthoquinone derivatives were synthesized via the reaction of arylidenemalononitrile and 2‐hydroxynaphthalene‐1,4‐dione in the mixed solvent of N,N‐dimethylformamide and glacial acetic acid (HOAc) under microwave irradiation without catalyst. This protocol has the notable advantages of short reaction time, high yield, and convenient operation. J. Heterocyclic Chem., (2009).
Concurrent formation of five and eight‐membered heterocyclic methylphosphonates in cyclization reactions from diethyleneglycole
Authors: Moghimi Abolghasem , Rafiei Javad , Baghaie Parvin , Aghabeygi Shokoofeh , Moosavi S. Mojtaba
Published: August 2009

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Two methodologies have been investigated for the preparation of heterocyclic methylphosphonate using diethyleneglycole and either MPDC or DMMP as the bifunctional group starting materials needed for cyclization reactions. In addition to the eight‐membered ring methylphosphonate I the five‐membered ring methylphosphonate II was unexpectedly found to be formed during the cyclization reactions. This small‐size cyclic methylphosphonate may have been generated from an intramolecular cyclization reaction by the nucleophilic attack of the ether oxygen atom of the intermediate MeP(O)(X)OCH2CH2OCH2CH2OH (X = Cl or OMe). The resulting cyclic phosphonates were purified and characterized by NMR and mass spectroscopy. J. Heterocyclic Chem., (2009).
Utility of p‐phenylenediformamidine in the synthesis of bisazoles and phenanthroline
Authors: Al‐Mousawi Saleh M. , Elassar Abdel‐Zaher A.
Published: August 2009

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p‐Phenylenediformamidine 1 is readily obtained upon treating p‐phenylenediamine with dimethylformamide dimethyl acetal (DMFDMA) by heating or by microwave irradiation. Compound 1 was treated with active methylene nitriles followed by hydrazine hydrate derivatives to give bisaminopyrazole derivatives. Other bisazoles can be obtained by reacting 1 with aminoazole derivatives. Cyclization of Bis [2‐(p‐phenelyeneimino)malononitrile] to 1,10‐diaminophenanthroline‐2,9‐dicarbonitrile is also reported. J. Heterocyclic Chem., (2009).
Reinvestigation of alternative method for the preparation of dibenz[b,f][1,4]oxazepine
Authors: Fakhraian Hossein , Nafary Yaser
Published: August 2009

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Two distinct alternative methods using different starting materials for the preparation of dibenz[b,f][1, 4]oxazepine (7, CR) were reinvestigated. The possibility of trans‐cis conversion of the Schiff base 5cis, 5trans (produced from 1 and 2) is considered the favorable orientation that leads to cyclization (production of 7). Fluoro derivative of 1 afforded excellent and more convenient conditions for the one pot preparation of high yield pure 7. The presence of only trans configuration for the imine 6cis, 6trans (produced from 3 with 4) and the impossibility of its conversion to cis, makes it inadequate for the preparation of 7. J. Heterocyclic Chem., (2009).
Fiber‐type distribution of the perivertebral musculature in Ambystoma
Authors: Schilling Nadja , Deban Stephen M.
Published: August 2009

Many salamanders locomote in aquatic and terrestrial environments. During swimming, body propulsion is solely produced by the axial musculature generating lateral undulations of the trunk and tail. During terrestrial locomotion, the trunk is oscillated laterally in a standing wave, and body propulsion is achieved by concerted trunk and limb muscle action. The goal of this study was to increase our knowledge of the functional morphology of the tetrapod trunk. We investigated the muscle‐fiber‐type distribution and the anatomical cross‐sectional area of all perivertebral muscles in Ambystoma tigrinum and A. maculatum. Muscle‐fiber‐type composition was determined in serial cross‐sections based on m‐ATPase activity. Five different body segments were investigated to test for cranio‐caudal changes along the trunk. The overall fiber‐type distribution was very similar between the species, but A. tigrinum had relatively larger muscles than A. maculatum, which may be related to its digging behavior. None of the perivertebral muscles possessed a homogeneous fiber‐type composition. The M. interspinalis showed a distinct layered organization and may function to ensure the integrity of the spine (local stabilization). The M. dorsalis trunci exhibited the plesiomorphic pattern for notochordates in having a distinct superficial layer of red and intermediate fibers, which covered the central white fibers; therefore, it is suggested to function as a mobilizer and a stabilizer of the trunk, but, may also be involved in modulating body stiffness. Similarly, the M. subvertebralis showed clear regionalizations, implying functional subunits that can stabilize and mobilize the trunk as well as modulate of body stiffness. Cranio‐caudally, neither the fiber‐type composition nor the a‐csa changed dramatically, possibly reflecting the need to perform well in both aquatic and terrestrial habitats. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.
Feasibility of diffusion‐weighted MRI for defining placental invasion
Authors: Morita Satoru , Ueno Eiko , Fujimura Mikihiko , Muraoka Mitsue , Takagi Koichiro , Fujibayashi Mariko
Published: August 2009

The purpose of this clinical note is to describe the feasibility of using diffusion‐weighted imaging for diagnosing placental invasion with a case of placenta increta and six cases without it. Diffusion‐weighted imaging (DWI) at a b‐value of 1000 sec/mm2 can clearly define the border between the placenta and myometrium because only the placenta shows very high signal intensity. The corresponding image at a b‐value of 0 sec/mm2 shows the myometrium with high signal intensity compared with the surrounding fat. Therefore, fusion of the two images can be used additionally to visualize thickness of the myometrium. As a result, DWI can be used to visualize the focal thinning of the myometrium caused by placenta increta, which has been difficult to diagnose on conventional magnetic resonance imaging sequences without contrast enhancement. However, the use of DWI for placental invasion should be determined following careful consideration of its risks and benefits, as fetus safety has not been established. J. Magn. Reson. Imaging 2009;30:666–671. © 2009 Wiley‐Liss, Inc.
Texture analysis of magnetization transfer maps from patients with clinically isolated syndrome and multiple sclerosis
Authors: Tozer D.J. , Marongiu G. , Swanton J.K. , Thompson A.J. , Miller D.H.
Published: August 2009

Purpose

To investigate the behavior of texture parameters derived from the gray level co‐occurrence matrix from gray matter (GM) and white matter (WM) (with lesions removed) segments of magnetization transfer ratio maps from controls and patients.

Materials and Methods

Magnetization transfer ratio maps from 23 controls and patients with either a clinically isolated syndrome (CIS) (38 patients) or clinically definite multiple sclerosis (MS) (35) were scanned and texture parameters extracted. The texture parameters were compared between the groups and correlated with clinical measures of disability in the MS patients to investigate any association with disease severity.

Results

No significant differences were found between the texture parameters from controls and CIS patients; however, several parameters differ between MS patients and the two other groups, particularly in the GM, but also in the WM. The expanded disability status score and timed walk test correlate with GM texture measures, while the Paced Auditory Serial Addition Test 3 score, a cognitive measure, correlates with WM texture. Texture abnormalities were seen in MS WM and GM, indicating tissue damage beyond classical WM lesions, the abnormalities being more evident in GM.

Conclusion

The findings highlight potential for texture analysis measures in classifying central nervous system demyelinating diseases that warrants further investigation. J. Magn. Reson. Imaging 2009;30:506–513. © 2009 Wiley‐Liss, Inc.
Structure and antioxidant activity of brominated flavonols and flavanones
Authors: Justino Gonçalo C. , Rodrigues Margarida , Florêncio M. Helena , Mira Lurdes
Published: August 2009

Hypobromous acid (HOBr) produced by both eosinophil peroxidase (EPO) and myeloperoxidase (MPO) is a stronger oxidant than HOCl, and is also essential for optimal and efficient microbial killing. Considering the potential cytotoxic effect of HOBr, if it is formed outside the phagosome, it should be useful to scavenge it in order to protect the nearby tissues. In this study the ability of selected flavonoids to protect against HOBr mediated oxidation reactions was performed through a competitive reaction, and the resulting products identified by high performance liquid chromatography (HPLC) and electrospray ionization tandem mass spectrometry(ESI‐MS/MS). Several structural features were found to be important to confer high antioxidant activity to flavonoids towards HOBr: the C2C3 double bond and the 3OH group in the C‐ring, and the presence of both 5OH and 7OH groups in the A‐ring. The MS results showed that flavonoids are dibrominated in the A‐ring, suggesting that (except for fisetin) bromination occurs at C6 and C8 positions, through an electrophilic aromatic substitution reaction. The chemical modifications achieved by bromination of flavonoids have changed their biological properties, presenting their brominated derivatives higher antioxidant activity, as radical scavengers, and higher lipophilicity, than the parent flavonoids. Brominated flavonoids may then diffuse easily through membranes increasing the intracellular concentration of the compounds. These locally formed metabolites may also interact with signaling cascades involving cytokines and regulatory transcription factors, thus playing a role in inflammation and in the regulation of immune response. Copyright © 2009 John Wiley & Sons, Ltd.
Extent and deglacial chronology of the last British–Irish Ice Sheet: implications of exposure dating using cosmogenic isotopes
Authors: Ballantyne Colin K.
Published: August 2009

Over 160 10Be and 36Cl exposure ages pertaining to the extent and chronology of the last British–Irish Ice Sheet (BIIS) are critically reviewed. Despite uncertainties inherent in the use of exposure ages, this approach has demonstrated that at the Last Glacial Maximum (LGM; ca. 26–21 ka) the BIIS extended over all low ground in Scotland and all (or almost all) of Ireland, consistent with recent models depicting extension of the last BIIS to the Atlantic shelf edge. All exposure ages obtained for high‐level sites above trimlines on the mountains of northwestern Scotland and Ireland pre‐date the LGM. This finding confirms that high plateaux in these areas escaped significant glacial erosion, probably under a protective cover of cold‐based glacier ice that remained frozen to the underlying substrate. In terms of deglaciation chronology, the southern Irish Sea basin was probably deglaciated by 19–18 ka, with extensive deglaciation of low ground in Ireland and northeastern Scotland prior to ca. 14.5 ka. Ice cover on low ground in northwestern Scotland apparently persisted after 14.0 ka, suggesting survival of ice in favourable locations during the Lateglacial Interstade (ca. 14.5–12.9 ka). Attempts to date readvances have had mixed success. The Wester Ross Readvance in northwestern Scotland was initially dated to ca. 16.3 ka, but more recent research implies a much younger age (ca. 14.0–13.5 ka). Exposure ages indicating a prolonged stillstand during ice sheet retreat in the Cairngorms at ca. 14.5–14.0 ka conflict with ages obtained on postglacial rockslides and basal radiocarbon dates, which indicate deglaciation before ca. 15.5–15.0 ka. Exposure dating has been successfully employed to confirm a Loch Lomond Stadial (ca. 12.9–11.5 ka) age for moraines in several mountain areas, and to constrain the minimum altitude of the ice cap that extended over the Western Grampians at that time. Copyright © 2009 John Wiley & Sons, Ltd.
Visible laser–induced photoreduction of silver 4‐nitrobenzenethiolate revealed by Raman scattering spectroscopy
Authors: Kim Kwan , Lee Yoon Mi , Lee Hyang Bong , Park Yeonju , Bae Tae Yeol , Jung Young Mee , Choi Cheol Ho , Shin Kuan Soo
Published: August 2009

We have investigated the photochemical characteristics of silver 4‐nitrobenzenethiolate (Ag‐4NBT) by means of Raman spectroscopy. When Ag‐4NBT is irradiated with an argon ion laser at 514.5 nm, its Raman spectrum changes over time, resulting in the production of 4NBT‐capped silver nanoparticles. The surface‐enhanced Raman scattering (SERS) spectrum of 4NBT adsorbed on those Ag nanoparticles is subsequently converted to that of 4‐aminobenzenethiol (4ABT). These surface‐induced photoreduction characteristics were investigated by monitoring the growth of Raman peaks of 4ABT as a function of the laser exposure time. Water vapor or ambient conditions were more effective than vacuum conditions for the photoreduction of 4NBT to 4ABT. Nonetheless, the occurrence of photolysis even under vacuum conditions suggests that the benzene ring hydrogen atoms might be the H‐atom source of the nitro‐to‐amine group conversion although in ambient conditions water or solvent molecules trapped inside the Ag‐4NBT should be the primary H‐atom source and facilitate the transfer of electrons, as well as the diffusion of Ag atoms to form highly SERS‐active nanoaggregates. Copyright © 2009 John Wiley & Sons, Ltd.
Fiber‐optic distributed sensor based on a Sagnac interferometer with a time delay loop for detecting time‐varying disturbance
Authors: Xu Wenyuan , Zhang Chunxi , Liang Sheng , Li Lijing , Lin Wentai , Yang Yusheng
Published: August 2009

A fiber optic distributed sensor, based on a Sagnac interferometer for determining the location of time‐varying disturbance, is presented in this paper. The proposed distributed sensor constitutes a Sagnac interferometer with an additional time delay fiber loop. Due to the time‐division multiplexing technique, by employing the light pulse, there are actually two Sagnac interferometers utilized for distributed sensing, and the amplitudes of the time‐division multiplexed signals are distinguished and converted to location information. Experimental results obtained with a 10 km long sensing fiber are discussed. The proposed distributed sensor has the advantages of capability of real time sensing, low cost and simple configuration. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2564–2567, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24672
An efficient analysis of frequency selective surface in spectral domain with RWG basis functions
Authors: Zhuang Wei , Chen Riu S. , Ding Dazhi Z. , Wang Daoxiang X.
Published: August 2009

In this article, the spectral domain method of moment is utilized to analyze frequency selective surface with RWG basis functions for arbitrarily shaped metal geometry. The Fourier transform of the RWG basis function can be expressed in the analytical form and the fast convergence characteristic can reduce the computation time of impedance matrix. Some examples are calculated to demonstrate the efficiency of the proposed method. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2567–2570, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24674
Design of square microstrip antenna for dual wideband operation
Authors: Singh Kishan , Konda R. B. , Sameena N. M. , Mulgi S. N.
Published: August 2009

A novel design of square microstrip antenna is designed for dual band operation. By embedding unequal length inverted right angle slot at optimum place on the square patch, the upper operating band enhanced from 27.53 to 60.01% with minimum change in the lower operating band retaining the nature of broad side radiation characteristics. The proposed antennas may find application in radar communication. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2578–2582, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24678
Design of multilayer triangular substrate integrated waveguide filter in LTCC
Authors: Shen Wei , Sun Xiao‐Wei , Yin Wen‐Yan , Mao Jun‐Fa , Wei Qi‐Fu
Published: August 2009

This article proposes a four‐pole quasi‐elliptic function triangular substrate integrated waveguide bandpass filter, which was fabricated using multilayer low‐temperature cofired ceramic technology. In our design, neural network inverse model is adopted to fast capture the sizes of TSIW cavities, with the coupling matrix transformation implemented to achieve cross coupling on the basis of multilayer TSIW. A slot on the top metal layer is introduced so as to suppress the two higher spurious modes. The filter has 65% size reduction in comparison with its planar counterpart, with good agreement obtained between the simulated and measured S‐parameters. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2582–2585, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24680
Ku‐band substrate integrated waveguide transitions between layers
Authors: Song Kaijun , Fan Yong
Published: August 2009

Two types of the substrate integrated waveguide (SIW) transitions between layers are presented in this letter. The SIW circuits have been used to achieve the transition from one layer to other layer. These two types of SIW transitions between layers operating in Ku‐band have been designed and fabricated. The measured 10‐dB return loss bandwidth of the transition between adjacent layers is about 7 GHz, and the measured 1‐dB insertion loss bandwidth is about 5 GHz; the measured 13‐dB return loss bandwidth of the unadjacent‐layers transition is demonstrated to be about 3.7 GHz, and the measured insertion losses are less than 2 dB from 11.2 GHz to 15 GHz. The simulated and measured results indicate that these two SIW transitions take the advantages of broadband, low insertion loss, and low profile. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2585–2588, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24685
Analysis of the human body on the radiation of FM handset antenna
Authors: Vergés Jordi , Anguera Jaume , Puente Carles , Aguilar David
Published: August 2009

A simple human body phantom model is proposed and used to demonstrate that the radiation efficiency of an internal handset antenna operating at the FM band can be improved for a particular holding position up to 10 dB. To corroborate the numerical results, an experiment using a real human body has been performed showing very good agreement. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2588–2590, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24686
Compact and ultra wideband printed eliptical monopole antenna with modified‐shape ground plane
Authors: Karimabadi S. S. , Attari A. R.
Published: August 2009

A novel compact and ultra wideband antenna with a printed monopole structure is presented in this article. It is demonstrated that with a modified‐shape ground plane, an ultra wide bandwidth can be achieved with small radiation element size. Simulation and measurement results show that the antenna impedance bandwidth covers the frequency range of 3.1–10.6 GHz. Performance of the proposed antenna is examined in terms of return loss, radiation pattern, transfer function and received signal waveform. It is shown that the proposed antenna has almost omni‐directional radiation pattern over the whole band. To evaluate the capability of antenna in preserving the waveform of source pulse the fidelity factor is calculated. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2604–2607, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24689
Quadrifilar helical antenna design for satellite‐mobile handsets using genetic algorithms
Authors: Zhou D. , Abd‐Alhameed R. A. , See C. H , Excell P. S. , Hu Y. F. , Khalil K. , McEwan N. J.
Published: August 2009

A circularly polarized quadrifilar helical antenna, operated at 2.4 GHz and intended for applications in satellite mobile communications, is designed using genetic algorithms (GA). The antenna was firstly considered as a test on an infinite ground plane and then optimized further on small size handsets. The performance of the optimized antenna design was analyzed using commercial simulators in terms of impedance match, axial ratio, and gain. Results for the optimal antenna met the design objectives subject to certain parametric constraints. The design shows the capabilities of GA as an efficient optimization tool for selecting globally optimal parameters to be used in simulations with an electromagnetic antenna design code, seeking convergence to specific design specifications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2668–2671, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24694
Coplanar waveguide fed taper arc slot antenna for microwave imaging and ultra wide band applications
Authors: Hossain I. , Noghanian S. , Shafai L. , Pistorius S.
Published: August 2009

Design features of a reduced size coplanar waveguide (CPW) fed ultra wide band (UWB) taper arc wide slot antenna with impedance Band Width (BW) of 9.69 GHz have been illustrated. The antenna depicts satisfactory performance both on free space and when immersed in three different coupling materials for application in the experimental MI set up. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2607–2611, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24701
A 1.5‐V transformer‐based ultra‐wideband LNA chip design
Authors: Huang Jhin‐Fang , Shie Pei‐Jiuan , Liu Ron‐Yi
Published: August 2009

In this article, a low‐noise amplifier (LNA) for ultra‐wideband (UWB) systems operating at 3–5 GHz frequency range is presented. The proposed LNA uses an on‐chip transformer to achieve the realization of a wideband input‐integrated matching to the antenna impedance, as well as the cascode amplifier with shunt peaking can provide a high power gain. The transformer‐based LNA fabricated in a TSMC 0.18‐μm CMOS process with 1.5 V supply voltage achieves a maximum power gain of 19.2 dB in addition to the minimum noise figure (NF) of 3.5 dB, an input return loss (S11) smaller than −9.3 dB over the whole frequency range. This circuit also present an input‐referred third‐order intercept point (IIP3) of −11 dBm at 5 GHz and an input‐referred 1 dB compression point of −21 dBm at 5 GHz. The chip area including pads is only 0.8 mm2 and power dissipation is 13.5 mW. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2649–2652, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24705
Metamaterial‐based phased array for directional beam steering
Authors: Ourir Abdelwaheb , de Lustrac A.
Published: August 2009

Ultracompact metamaterial‐based cavity (thickness λ/15) is proposed to realize a low secondary lobes level and highly directive phased array antenna. The cavity is fed by an array of four patch antennas designed to operate at around 9.5 GHz. The radiation patterns of the phased arrays are compared with those of their respective metamaterial‐based cavity antennas. The latter structures have lower secondary lobes and provide higher gain and directivity. Moreover, the cavities enhance the beam steering of the phased arrays. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2653–2656, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24709
A novel method of utilizing practical optical source with relatively‐narrow spectrum for OCDMA
Authors: Zheng Jilin , Wang Rong , Pu Tao , Lu Lin , Chen Peng , Fang Tao , Chen Xiangfei , Cheng Yun
Published: August 2009

A novel method of utilizing optical source with relatively‐narrow spectrum is proposed for coherent temporal‐phase optical code‐division multiple‐access (OCDMA) system based on equivalent phase shift super‐structure fiber Bragg grating (EPS‐SFBG). Simulation and experiment show that better decoding performance will be achieved by making the source's relatively‐narrow spectrum cover half‐side of encoding spectrum. Meanwhile, we can obtain more tolerance of wavelength deviation between the encoder and decoder and less inter‐symbol‐interference (ISI) and corresponding inter‐symbol beat noise (BN) comparing with traditional matching method. The improvements will make low‐cost optical source with relatively‐narrow spectrum fit for OCDMA system and accordingly accelerate the OCDMA's practical application. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2688–2691, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24711
Design of a meta‐screen for near‐zone field focalization at optical frequencies
Authors: Scorrano Luca , Bilotti Filiberto , Vegni Lucio
Published: August 2009

In this letter, we propose the design of a nano‐circuit reactive artificial screen for the synthesis of a given field pattern with sub‐wavelength features at visible frequencies. The meta‐screen consists of a discrete set of dielectric cells, behaving as lumped reactive elements. The cells have been designed according to the recently proposed new concept of metactronics. The spatial distribution of the cells, and the inter‐element electrically small spacing enables the focalization of a sub‐wavelength spot beyond the diffraction limit at a prescribed focal distance. The design is supported by full‐wave simulations, showing the actual focusing properties of the artificial screen proposed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2718–2721, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24719
Transformation optics‐inspired metamaterial coatings for controlling the scattering response of wedge/corner‐type structures
Authors: Gallina Ilaria , Castaldi Giuseppe , Galdi Vincenzo
Published: August 2009

Transformation optics has recently emerged as a powerful and systematic approach to design application‐oriented metamaterials. In this letter, following up on our previous studies on thin planar retroreflectors, we show how it is possible, in principle, to design “transformation medium” coatings capable of controlling the scattering response of metallic corner‐ and wedge‐type structures so as, e.g., to strongly enhance the specularly reflected component. We validate our results via a full‐wave study of the near‐ and far‐field responses, and envisage possible applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2709–2712, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24720
Parametric study of guided resonances in octagonal photonic quasicrystals
Authors: Gallina Ilaria , Ricciardi Armando , Pisco Marco , Campopiano Stefania , Castaldi Giuseppe , Cusano Andrea , Cutolo Antonello , Galdi Vincenzo
Published: August 2009

In this article, following up on our previous investigations on guided resonances (GRs) in photonic quasicrystal slabs based on octagonal (quasiperiodic) tilings, we present the salient results from a parametric study of the GR properties, varying the air/dielectric fraction, and the slab refractive index and thickness. Our results, obtained via full‐wave simulations, show similar qualitative trends as those observed in the literature for periodic photonic crystal slabs. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2737–2740, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24721
Bandgap properties of low‐index contrast aperiodically ordered photonic quasicrystals
Authors: Zito Gianluigi , Priya Rose T. , Di Gennaro Emiliano , Andreone Antonello , Santamato Enrico , Abbate Giancarlo
Published: August 2009

We numerically analyze, using Finite Difference Time Domain simulations, the bandgap properties of photonic quasicrystals with a low‐index contrast. We compared 8‐, 10‐, and 12‐fold symmetry aperiodically ordered lattices with different spatial tiling. Our results show that tiling design, more than symmetry, determines the transmission properties of these structures. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2732–2737, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24724
On the dispersion equation for a homogeneous, bi‐isotropic waveguide of arbitrary cross‐section
Authors: Ioannidis A. D. , Kristensson G. , Sjöberg D.
Published: August 2009

In this article, we consider the propagation problem inside a waveguide filled with a homogeneous bi‐isotropic material. The cross section of the waveguide is assumed arbitrary. By using the classical theory for the 2D Helmholtz equation in the cross section and the null‐field approach, we obtain the dispersion equation in an implicit form. The final equation is a potential candidate for the solution of the direct and the inverse propagation problems. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2701–2705, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24726
Behavioral modeling of GaN‐based power amplifiers: Impact of electrothermal feedback on the model accuracy and identification
Authors: Quaglia Roberto , Camarchia Vittorio , Cappelluti Federica , Guerrieri Simona Donati , Lima Eduardo G. , Ghione Giovanni , Pirola Marco
Published: August 2009

In this article, we discuss the accuracy of behavioral models in simulating the intermodulation distortion (IMD) of microwave GaN‐based high‐power amplifiers in the presence of strong electrothermal (ET) feedback. Exploiting an accurate self‐consistent ET model derived from measurements and thermal finite‐element method simulations, we show that behavioral models are able to yield accurate results, provided that the model identification is carried out with signals with wide bandwidth and large dynamics. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2789–2792, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24732