bluuebunny/crossref_metadata_2025_split huggingface dataset:
A wideband loop‐type antenna
Authors: Moon Sungjin , Lee Hongkoo , Kim Hyeongdong 
Published: April 2015

ABSTRACTA new feed structure with a loop‐type radiator is proposed for achieving a wide bandwidth characteristic. The method for achieving a wide impedance bandwidth characteristic is to control the input impedance of the feed structure using a parallel capacitor and inductor. The size of the ground plane is 50 × 20 mm2, which is usually used as the ground for USB dongle applications. The size of the rectangular ground clearance for the loop‐type antenna is 8 × 4 mm2. The proposed antenna was designed and measured using HFSS and a 3D CTIA OTA chamber. The center frequency is 2.45 GHz and the impedance bandwidth under VSWR = 2:1 is 550 MHz (2.18–2.73 GHz), which is adequate for long term evolution bands (7, 30, 40) and Wi‐Fi applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1742–1744, 2015
A new time‐domain corner diffraction coefficient for metallic and dielectric objects for UWB signals
Authors: Bansal Bajrang , Soni Sanjay 
Published: April 2015

ABSTRACTIn this article, a new time‐domain (TD) corner diffraction coefficient is proposed for diffraction of ultrawide band signals by objects like metallic and dielectric three‐dimensional wedge and building. The proposed TD solution has been validated with the inverse fast Fourier transform of the corresponding frequency‐domain (FD) solution where the exact match confirms the accuracy of the proposed solution. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1760–1765, 2015
Planar graphene multifunctional component
Authors: Dmitriev Victor , Nascimento Clerisson 
Published: April 2015

ABSTRACTWe suggest and investigate theoretically a new graphene electromagnetic tunable multifunctional component for THz region. The structure represents a planar square array of graphene elements placed on both sides of a thin dielectric substrate. By changing electrostatically the graphene chemical potential, the frequency characteristics of the pass‐band and stop‐band filter can be displaced providing a dynamic control of the filter. This property and combination of a high peak and a deep valley in the transmission response allow one to use the component also as a switch in two different frequency controllable bands. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1755–1760, 2015
A reconfigurable monolithic step‐up autotransformer
Authors: Ryu Hyunsik , Nam Ilku , Lee Ockgoo 
Published: April 2015

ABSTRACTThis article presents a reconfigurable monolithic step‐up autotransformer. In addition, its reconfigurable operation has been analyzed using a proposed nonideal transformer model. A corresponding complete model for a reconfigurable autotransformer has also been developed on a silicon substrate case. The proposed reconfigurable autotransformer was fabricated using a standard 65‐nm CMOS process. The measurement results demonstrate that the fitted curves using the proposed complete model agree well with the measured results. The proposed reconfigurable autotransformer can perform the required impedance changes depending on the power amplifier output power change with low insertion loss. The 50‐Ω load impedance is transformed to a low value of 3.28 Ω in high power (HP) mode operation, and it is transformed to a high value of 12.26 Ω in low power (LP) mode operation at 0.9 GHz. The transformer insertion losses in HP and LP mode operations are −1.424 dB and −0.706 dB at 0.9 GHz, respectively. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1662–1666, 2015
Compact multiband dual reconfigurable folded planar monopole antenna
Authors: Abou Al‐alaa M. , Elsadek H. A. , Abdallah E. A. 
Published: April 2015

ABSTRACTCompact multiband dual reconfigurable monopole antenna is presented. To achieve frequency and polarization reconfigurability, PIN diodes as well as MEMS switches are used. For frequency reconfigurability, one switch was inserted on the patch side. When this switch is OFF; the antenna operates at four bands 2.45 GHz, 3 GHz, 3.69 GHz, and 5.5 GHz with corresponding impedance bandwidth of 9.95%, 5.96%, 12.57%, and 10.76%, respectively. When the switch is ON; the antenna operates at 2.64 GHz, 3.67 GHz, 4.94 GHz, and 5.3 GHz with impedance bandwidthes of 21.15%, 11.76%, 5.79%, and 4.12%, respectively. L‐shaped slit was inserted in the ground plane to obtain dual polarization at 5.3 GHz and 5.5 GHz bands. Another switch was inserted on this slit to alter between linear and circular polarization. Folded and meandered techniques are used for miniaturize the antenna size. Antenna size is 15 × 37 × 0.8 mm3 while the radiator part is 15 × 9 × 0.8 mm3. The proposed antenna is used in several applications as bluetooth (2400–2484 MHz), WLAN (802.11b/g/n [2.4–2.48 GHz], 802.11y [3.657–3.69 GHz], 802.11y [4.9 GHz], 802.11a/h/j/n [5.2 GHz]), Wi‐MAX (2.5–2.69 GHz), long term evolution (band7, band38, band41, band43), and S‐DMB (2605–2655 MHz). The antenna is analyzed using the CST Microwave Studio software package. The proposed antenna was fabricated and tested. Measurements and simulations show good agreement in most cases. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1557–1565, 2015
Novel dual band‐notched UWB antenna with T‐shaped slot and CSRR structure
Authors: Gao Guoping , He Lele , Hu Bin , Cong Xiaodong 
Published: April 2015

ABSTRACTA dual band‐notched ultrawideband antenna is proposed in this article. The antenna consists of a U‐shaped radiation patch and a ground plane which is symmetric with the edge of the radiation patch. By attaching two T‐shaped slots on the radiation patch and two rectangular complementary split‐ring resonators on both sides of the microstrip line, two notched bands, 3.3–3.7 GHz for WiMAX and 5.15–5.825 GHz for WLAN are achieved, respectively. The dimension of the proposed antenna is 24.6 mm × 38.1 mm × 1.5 mm. The measured result shows that the antenna has a wide impedance bandwidth and omnidirectional radiation patterns. Moreover, time‐domain characteristics and conceptual circuit model based on the input impedance of the proposed antenna are investigated to verify the dual band‐notched characteristics. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1584–1590, 2015
Design of X‐band substrate integrated waveguide bandpass filter with dual high rejection
Authors: Rhbanou Ahmed , Bri Seddik , Sabbane Mohamed 
Published: April 2015

ABSTRACTThis article presents a bandpass substrate integrated waveguide (SIW) filter with dual high rejection, using the topology with iris and the SIW resonators. The simulated results of this filter have shown that the passband is from 9.18 to 10.37 GHz while the insertion loss is −1.19 dB within 12.17% bandwidth around 9.775 GHz and input return loss in the passband is better than −15 dB, with high rejection of −57.04 dB at the frequency 8.81 GHz and a second rejection of −49.34 dB at the frequency 10.94 GHz. All the structures are designed on a single substrate of Arlon 25N permittivity 3.38. The compatibility with planar circuits is provided via a specific microstrip transition (microstrip tapered transitions). © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1744–1752, 2015
A dual band LTEPIFA antenna for M2M applications
Authors: Loutrids Abraham , John Matthias , Ammann Max J. 
Published: April 2015

ABSTRACTA dual Planar Inverted‐F‐Antenna for M2M application is proposed. The antenna covers the lower long term evolution (LTE) band (690–960 MHz) and partially, the upper LTE band (1670–2067 MHz). The antenna is low cost with omnidirectional radiation characteristics. The measured total efficiency and gain are better than 58% and 0.8 dBi across the operational frequency range. A parametric study of key geometrical parameters is made. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1655–1658, 2015
A multifactorial analysis of complex pharmaceutical platforms: an application of design of experiments to targetable polyacrylamide and ultrasound contrast agents
Authors: Bloch Meital , Kenett Ron , Jablonowski Lauren , Wheatley Margaret , Yavin Eylon , Rubinstein Abraham 
Published: April 2015

To improve visualization of malignant regions in the colon epithelium during diagnostic procedures, we have recently suggested a multimodal system comprising the water‐soluble cationized polyacrylamide, tagged with the near infrared dye derivative IR‐783‐S‐Ph‐COOH [fluorescent‐cationized polyacrylamide (Flu‐CPAA)] and conjugated to the recognition peptide VRPMPLQ to form Flu‐CPAA‐Pep. The fluorescent‐cationized polyacrylamide‐peptide conjugate (Flu‐CPAA‐Pep) is then incorporated into echogenic microbubbles (MBs) made of polylactic acid (PLA) to protect it from pre‐mature interactions with plasma proteins upon intravenous administration. It is expected that under directed ultrasound interrogation the Flu‐CPAA‐Pep cargo would be released in the region of interest, as a result of the MBs rupture into submicron PLA fragments (SPF). Due to their nanoscale dimension, the SPF will escape from the vasculature and allow a specific binding of the Flu‐CPAA‐Pep to the suspected malignant tissue.The complex nature of the system requires a multifaceted statistically based experimental design. Here we apply a design of experiment methodology to enable effective screening of key parameters in our experimental setup. It enables the assessment of the role of the different formulation parameters by identifying statistically significant interactions as observed in vitro (cell lines) and in vivo (colon cancer‐induced rat model). Particularly important was the identification of the interaction between the fraction (mol%) of the cationic monomer in the Flu‐CPAA and (a) the presence of recognition peptide as assessed in the in vitro experiments and (b) the use of a presenting platform (whether MBs or SPF) as assessed in the in vivo experiments. Copyright © 2015 John Wiley & Sons, Ltd.
Effect of additive length and chemistry on the morphology of blends of conjugated thiophenes and fullerene derivative acceptor molecules
Authors: Marsh Hilary S. , Jayaraman Arthi 
Published: April 2015

ABSTRACTSmall molecule additives have been shown to increase the device efficiency of conjugated polymer (donor) and fullerene derivative (acceptor) based organic solar cells by modifying the morphology of the device active layer. In this paper we conduct a systematic study of how additives affect the donor‐acceptor morphology using molecular dynamics simulations of blends of thiophene‐based oligomers, mimicking poly(3‐dodecylthiophene) (P3DDT) or poly(2,2′:5′,2”‐3,3”‐didocyl‐terthiophene) (PTTT), and fullerene derivatives with additives of varying length and chemical functionalization, mimicking experimentally used additives like methyl ester additives, diiodooctane, and alkanedithiols. We find that functionalization of additives with end groups that are attracted to acceptor molecules are necessary to induce increased donor‐acceptor macrophase separation. In blends where acceptors intercalate between oligomer alkyl side chains, functionalized additives decrease acceptor intercalation. Functionalized additives with shorter alkyl segments increase acceptor macrophase separation more than additives with same chemical functionalization but longer alkyl segments. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 1046–1057
The willingness and actual situation of Chinese cancer patients and their family members participating in medical decision‐making
Authors: Zhang Jie , Yang Dan , Deng Yaotiao , Wang Ying , Deng Lei , Luo Xinmei , Zhong Wuning , Liu Jie , Wang Yuqing , Jiang Yu 
Published: April 2015

AbstractObjectiveIn China, not only patients and physicians are involved in medical decision‐making (MDM) but also the patients' family members. The objective is to investigate the willingness and actual situation of cancer patients and their family members participating in the MDM process.MethodsIn this cross‐sectional study, questionnaires were administered to 247 pairs of cancer inpatients and their relatives. Information regarding participants' willingness and actual experience during the decision‐making process was documented. Eligible participants were cancer inpatients or their relatives, 18 years of age or older, and informed of the cancer diagnosis. All the patients should have received chemotherapy.ResultsThe effective response rate was 72.9% (180/247). Over half of the patients (53.3%) and family members (57.8%) were willing to be part of the MDM process. In contrast, only 35.0% of patients and 46.1% of family members actually experienced this process (p = 0.001 and p = 0.011, respectively). Fewer family members (42.2%) than patients (53.3%) believed that patients should be involved in the MDM process (p < 0.001). Patients who were the head of their family (odds ratio 2.577, 95% CI 1.198–5.556, p = 0.015) experienced more involvement in MDM.ConclusionsAlthough more than half of Chinese cancer patients and family members wanted to be part of MDM, the actual participation was below their expectation. Majority of family members do not want the patients to be involved in the process of MDM. Copyright © 2015 John Wiley & Sons, Ltd.
Metabolic chemotypes of CITES protected Dalbergia timbers from Africa, Madagascar, and Asia
Authors: McClure Pamela J. , Chavarria Gabriela D. , Espinoza Edgard 
Published: April 2015

RationaleThe genus Dalbergia includes approximately 250 species worldwide. Of these, 58 species are of economic importance and listed under CITES. Identification of illegal transnational timber trade is a challenge because logs or boards lack the typical descriptors used for species identification such as leaves and flowers; therefore, frequently the lowest taxonomic determination of these tree byproducts is genus. In this study, we explore the use of Direct Analysis in Real Time (DART) Time‐Of‐Flight Mass Spectrometry (TOFMS) in making species determinations of protected Dalbergia trees from Africa, Madagascar, and Asia.MethodsMetabolic profiles were collected using DART TOFMS from the heartwood of seven species and the sapwood of 17 species of Dalbergia. Also included in this study are 85 Dalbergia heartwood samples from Madagascar that were only identified to genus. In all, 21 species comprising 235 specimens were analyzed, the metabolic chemotypes were interpreted, and the spectra were analyzed using chemometric tools.ResultsDalbergia cochinchinensis and Dalbergia spp. from Madagascar (both CITES Appendix II) could be differentiated from each other and from the non‐protected Dalbergia latifolia and Dalbergia melanoxylon.ConclusionsDART TOFMS is a valuable high‐throughput tool useful for making phytochemical classifications of Dalbergia spp. The data produced allows the protected Dalbergias from Madagascar to be distinguished and can differentiate closely related rosewood trees. Published in 2015. This article is a U.S. Government work and is in the public domain in the USA.
Identification of alkaloid constituents from Fangchi species using pH control liquid‐liquid extraction and liquid chromatography coupled to quadrupole time‐of‐flight mass spectrometry
Authors: Sim Hee‐Jung , Yoon Soo Hwan , Kim Min Sun , Kim Byungjoo , Park Hyun‐Mee , Hong Jongki 
Published: April 2015

RationaleFangchi (F.) species from four different origins have been widely used to treat or prevent diseases, and their main constitutes are several types of alkaloids. Identification of alkaloids in F. species is a necessary step to understand the therapeutic properties of each different origin, but this has not yet been fully performed.MethodsSeveral types of alkaloids were extracted from F. species using ultrasonication with 70% CH3OH and the extract was partitioned at pH 2 and 12 to enrich alkaloid constituents and to remove interferences. The separation of alkaloids in the Fangchi extract was performed on a C18 column using gradient elution and their tandem mass spectra were obtained by quadrupole time‐of‐flight tandem mass spectrometry (QTOF‐MS/MS) to perform accurate mass measurements of fragment ions for the alkaloid constituents.ResultsSeveral types of alkaloids were successfully separated and identified by LC/ESI‐MS/MS. The structural assignment of individual alkaloids was performed based on convergence of MS/MS spectral data, pH partitioning behavior, LC retention behavior, and accurate mass measurements. The pH partition of the extract provided structural information about unknown alkaloids extracted from Fangchi species. A total of 28 compounds were identified and tentatively characterized, and of these 10 alkaloids were reported for the first time in the investigated F. species.ConclusionsThe chemical profiling of alkaloids in F. species with different origins was performed for the first time and provided diagnostic ions for diverse alkaloids in F. species. Marker compounds were suggested based on the 28 characterized compounds for quality evaluation and the differentiation of Fangchi species with four different origins. Copyright © 2015 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionization time‐of‐flight vs. fast‐atom bombardment and electrospray ionization mass spectrometry in the structural characterization of bacterial poly(3‐hydroxyalkanoates)
Authors: Impallomeni Giuseppe , Ballistreri Alberto , Carnemolla Giovanni Marco , Franco Domenico , Guglielmino Salvatore P. P. 
Published: April 2015

RationaleBacterial poly(3‐hydroxyalkanoates) (PHAs) are an emergent class of plastic materials available from renewable resources. Their properties are strictly correlated with the comonomeric composition and sequence, which may be determined by various mass spectrometry approaches. In this paper we compare fast‐atom bombardment (FAB) and electrospray ionization (ESI) to matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) of partially pyrolyzed samples.MethodsWe determined the compositions and sequences of the medium‐chain‐length PHAs (mcl‐PHAs) prepared by bacterial fermentation of Pseudomonas aeruginosa ATCC 27853 cultured in media containing fatty acids with 8, 12, 14, 18, and 20 carbon atoms as carbon sources by means of MALDI‐TOFMS of pyrolyzates, and compared the results with those obtained by FAB‐ and ESI‐MS in previous studies. MALDI matrices used were 9‐aminoacridine (9‐AA) and indoleacrylic acid (IAA).ResultsMALDI‐TOFMS was carried out in negative ion mode when using 9‐AA as a matrix, giving a semi‐quantitative estimation of the 3‐hydroxyacids constituting the PHAs, and in positive mode when using IAA, allowing us, through statistical analysis of the relative intensity of the oligomers generated by pyrolysis, to establish that the polymers obtained are true random copolyesters and not a mixture of homopolymers or copolymers.ConclusionsMALDI‐TOFMS in 9‐AA and IAA of partial pyrolyzates of mcl‐PHAs represents a powerful method for the structural analysis of these materials. In comparison with FAB and ESI, MALDI provided an extended mass range with better sensitivity at higher mass and a faster method of analysis. Copyright © 2015 John Wiley & Sons, Ltd.
Fragmentation of an Intermittent Stream During Seasonal Drought: Intra‐annual and Interannual Patterns and Biological Consequences
Authors: Hwan J. L. , Carlson S. M. 
Published: April 2015

AbstractIntermittent streams lose surface flow during some portion of the year and can be important breeding and rearing habitats for stream biota. However, habitat contraction and deteriorating water quality across the summer can result in harsh conditions and mortality. We explored patterns of drying in a small intermittent stream across the summer in Mediterranean‐climate California, including across 4 years that differed in antecedent precipitation. Wet–dry mapping revealed earlier stream fragmentation following dry winters and that entire sections of the stream varied in their propensity to dry suggesting an important influence of geomorphology on drying. Within two ‘slow‐drying’ reaches, initial riffle volumes were higher following wetter winters, but the rate of riffle drying was higher following wet years, presumably because higher initial volumes resulted in greater drying capacity. Initial pool volumes were similar across years, but the rate of pool drying was faster following dry versus wet winters (pool half‐life ranged from 9.7 weeks in the driest year to 26.3 weeks in the wettest year). Stream temperature differed among years, but differences were slight, and temperatures rarely exceeded optimal conditions for trout growth. We observed limited movement of trout during drier years and found that movement was negatively associated with pool depth, riffle length and date, and positively associated with riffle volume. Overall, we found that antecedent rainfall influenced variability in pool drying more than riffle drying, that entire sections of the creek varied in their propensity to dry and that biological fragmentation preceded physical fragmentation by 3 to 7 weeks. Copyright © 2015 John Wiley & Sons, Ltd.
Data mining and education
Authors: Koedinger Kenneth R. , D'Mello Sidney , McLaughlin Elizabeth A. , Pardos Zachary A. , Rosé Carolyn P. 
Published: April 2015

An emerging field of educational data mining (EDM) is building on and contributing to a wide variety of disciplines through analysis of data coming from various educational technologies. EDM researchers are addressing questions of cognition, metacognition, motivation, affect, language, social discourse, etc. using data from intelligent tutoring systems, massive open online courses, educational games and simulations, and discussion forums. The data include detailed action and timing logs of student interactions in user interfaces such as graded responses to questions or essays, steps in rich problem solving environments, games or simulations, discussion forum posts, or chat dialogs. They might also include external sensors such as eye tracking, facial expression, body movement, etc. We review how EDM has addressed the research questions that surround the psychology of learning with an emphasis on assessment, transfer of learning and model discovery, the role of affect, motivation and metacognition on learning, and analysis of language data and collaborative learning. For example, we discuss (1) how different statistical assessment methods were used in a data mining competition to improve prediction of student responses to intelligent tutor tasks, (2) how better cognitive models can be discovered from data and used to improve instruction, (3) how data‐driven models of student affect can be used to focus discussion in a dialog‐based tutoring system, and (4) how machine learning techniques applied to discussion data can be used to produce automated agents that support student learning as they collaborate in a chat room or a discussion board. WIREs Cogn Sci 2015, 6:333–353. doi: 10.1002/wcs.1350This article is categorized under:

Computer Science > Machine Learning
Psychology > Learning