bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced technologies for UHD curved OLED TV
Authors: Han Chang‐Wook , Park Jung‐Soo , Choi Hong‐Seok , Kim Tae‐Shick , Shin Young‐Hoon , Shin Hong‐Jae , Lim Moo‐Jong , Kim Bong‐Chul , Kim Han‐Seop , Kim Bum‐Sik , Tak Yoon‐Heung , Oh Chang‐Ho , Cha Soo‐Youle , Ahn Byung‐Chul
Published: April 2015

Ultra‐high definition (UHD) curved organic light‐emitting diode (OLED) TV requires advanced technologies to realize mass production. White, red, green, and blue (WRGB) OLED TV based on stripe WRGB sub‐pixel structure has distinct advantages in luminance of white, faster response time, wider viewing angle, and potential higher resolution. In this paper, we will introduce technological progress for commercializing large‐sized and UHD curved OLED TV. Those technologies including oxide thin film transistors, white OLEDs, compensation circuit, and solid phase encapsulation enable panel size scalability as well as mass production with lifetime reliability.
Calculation of film stress from pitch measurements in LCD panel manufacturing
Authors: Burdette Steven R.
Published: April 2015

A method based on inverting a finite element model is presented for determining film stress from pitch changes before and after a film deposition step in liquid‐crystal display panel manufacturing. It differs from the conventional methods by making use of in‐plane deformation rather than out‐of‐plane measurements to calculate film stress. The resulting film stress is confounded with glass structural relaxation. Measurements of out‐of‐plane deformation at the edge of the sheet can be used with the pitch measurements to separate the effects of glass structural relaxation and film stress.
Optical deformations of azobenzene polymers: Orientation approach vs. photofluidization concept
Authors: Saphiannikova Marina , Toshchevikov Vladimir
Published: April 2015

Recently in literature appeared quite a number of claims that cyclic isomerization of azobenzene (azo) chromophores may cause an athermal transition of the glassy azo‐polymers or, more generally, glassy azo‐materials into a fluid state. In this study, we provide a critical overview of recently published findings and show that observations presented not only fail to support this photofluidization concept but rather show the contrary. The glassy azo‐materials remain in the solid state under light illumination. Thus, the sound claims made in the titles of recent studies contradict the experimental observations presented in their texts. Further, we discuss a number of rigorous studies, which present strong evidence against the photofluidization concept, including our own theoretical predictions made in the frame of orientation approach. This approach provides values of anisotropic light‐induced stress large enough to deform glassy azo‐polymers with diverse chemical structures. The values of the stress are in a perfect accord with recent experimental findings, which show deformation of the bonds in metal and graphene multilayers adsorbed on the top of illuminated azo‐polymers.
Radical Polymerization of Alkali Acrylates in Aqueous Solution
Authors: Drawe P. , Buback M. , Lacík I.
Published: April 2015

Monomer conversion versus time profiles for the radical polymerization of ionized acrylic acid (AA), 0.6 to 0.8 mol L−1 in aqueous solution, are measured at 50 °C via inline near‐infrared spectroscopy mostly on fully ionized AA, i.e., of alkali acrylates. Ionization reduces polymerization rate with the size of this effect being dependent on the type and on the concentration of the alkali counter cation, which is varied from lithium to rubidium. Polymerization rate becomes very small upon shielding the cation by complexation, whereas an enhancement of cation concentration, by addition of alkali chloride, may enhance polymerization rate such as to even reach the high rates observed with the radical polymerization of nonionized AA.

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On the equivalent circuit, input impedance, reflection coefficient, and bandwidth of printed monopole antenna
Authors: Bhattacharjee S. , Kshetrimayum R. S. , Bhattacharjee R.
Published: April 2015

This article presents the derivation of a closed form expression for input admittance of horizontal electric dipole over an ungrounded substrate using transmission line analogy. The derived expression is then used to calculate reflection coefficient of rectangular and circular printed monopole antenna (PMA) fed by a microstrip line. Analytical result for the reflection coefficient of both rectangular and circular PMA is verified using high frequency structure simulator (HFSS). For circular PMA, analytical, and simulated results are also compared with the measured results available in literature. Effect of the dimension and dielectric material on the antenna bandwidth is also studied and verified by HFSS. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1535–1538, 2015
Design and performance of wearable ultrawide band textile antenna for medical applications
Authors: Singh Nikhil , Singh A. K. , Singh Vinod Kumar
Published: April 2015

The concept of wearable products such as textile antenna are being developed which are capable of monitoring, alerting, and demanding attention whenever hospital emergency is needed, hence minimizing labor and resource. In the proposed work using textile material as a substrate, the ultra wideband antenna is designed especially for medical applications. Simulated and measured results here shows that the proposed antenna design meets the requirements of wide working bandwidth and provides 13.08 GHz bandwidth with very small size, washable (if using conductive thread for conductive parts) and flexible materials. Results in terms of bandwidth, radiation pattern, return loss as well as gain and efficiency are presented to validate the usefulness of the current proposed design. The work done here has many implications for future research and it could help patients with such flexible and comfortable medical monitoring techniques. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1553–1557, 2015
CSRR‐based compact penta band printed antenna for GPS/GSM/WLAN/WiMAX applications
Authors: Rosaline S. Imaculate , Raghavan Singaravelu
Published: April 2015

This article describes the design of a compact penta band triangular patch antenna backed by a hexagonal complementary split ring resonator operating in the GPS (1.57 GHz), GSM (1.80 GHz), WLAN (2.4/5 GHz), and WiMAX (3.5 GHz) bands. The antenna has a very compact dimension of 20 × 20 × 1.6 mm3. Three concentric hexagonal split ring slots in the ground plane yield the uppermost triple bonds (2.45, 3.5, 5.2 GHz) and the two parameterized radiating branches attached to the triangular patch accounts for the two lowermost operating bands (1.57, 1.8 GHz). A prototype of the proposed antenna is fabricated and tested. Simulated and measured results are in good agreement. It has a uniform radiation pattern over all the operating frequencies and a peak gain of 6.3 dBi at 3.5 GHz. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1538–1542, 2015
Estimation of complex permittivity using evolutionary algorithm from measured data of reflectance and transmittance in free space
Authors: Křesálek Vojtěch , Navrátil Milan
Published: April 2015

This article deals with the determination of permittivity and dissipation factor of thin layers in microwave range of electromagnetic spectra. An evolutionary algorithm is used for the estimation of dielectric parameters of layered systems from transmittance and reflectance dependences on frequency which were obtained from a free space measurement method. The results are subject to the usual uncertainties of research. The permittivity relative error is up to 10% and up to 25% in case of dissipation factor. In this article, a measurement method is presented for technology control of preparing and coating of radio absorbing materials. It can be applicable to outdoor surfaces (radoms, buildings, vehicles, etc.). © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1542–1546, 2015
Low‐profile broadband circularly‐polarized antennas with metamaterial structures
Authors: Wu Jianjun , Wang Zedong , Liu Xinxing , Yin Yingzeng
Published: April 2015

Low‐profile designs of meta‐based antennas are proposed for wideband circular polarization in this letter. Metamaterial structures of reactive impedance surface (RIS) and mushroom‐like structures are utilized, respectively, both of which have rectangular metallic unit cells. The metamaterial structures are simply fed by a microstrip feed line through a slot etched on the ground. The rectangular unit cells provide the 90° phase difference for the equivalent orthogonal modes from the 45°‐rotated slot to yield circular polarization. The measured results show that the antenna with RIS has an effective band of 10.7% (5.37–5.98 GHz) for |S11| < −10 dB, AR < 3 dB and average gain of 6 dBic on a low profile of 0.05λ0. The antenna with mushroom structures has an effective band of 10.4% (5.46–6.06 GHz) for |S11| < −10 dB, AR < 3 dB and average gain of 7 dBic. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1565–1568, 2015
Accurate and precise E‐field measurement for 2G and 3G networks based on IEEE Std. 1309‐2013
Authors: Narang Naina , Dubey Satya Kesh , Negi P. S. , Ojha V. N.
Published: April 2015

This article elaborates the theoretical and measurement technique to evaluate precise and accurate electric (E)‐field strength for frequency range 0.8–2.4 GHz (2G and 3G communication spectrum). The E‐field using a probe is precisely measured inside an indigenously designed transverse electromagnetic (TEM) cell as per IEEE Std. 1309‐2013. Key parameters for precise E‐ field measurement are explicated with their measurement results such as probe linearity, field distortion, and mismatch losses. E‐field strength of probe has been reported 9.91 V/m with an expanded uncertainty (k ∼ 2) of ±0.58 V/m for +18 dBm fed power at 915 MHz frequency. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1645–1649, 2015
Characteristic improvement of near‐field focused array microstrip planar antenna in ISM band
Authors: Samadi Fereshteh
Published: April 2015

A variation of the spot size reduction and power density enhancement problem have arisen in the study of focused array antennas for many applications such as hyperthermia. In this letter using nearly directional single‐element patch antenna, and optimizing phase distribution accuracy, power density enhancement, spot size reduction, and a significant reduction in the side lobe levels are achieved. The near‐field focused (NFF) array antenna worked at 2.4 GHz with size of 40 × 40 cm2. Both simulation and experimental studies are performed to validate NFF array antenna design and improvements. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1590–1593, 2015
An ultra low‐profile ultra wideband blade shape monopole antenna
Authors: Basaery Davood , Razavi Seyed Mohammadjavad , Armaki Seyed Hosein Mohseni , Mehrpour Mohammad
Published: April 2015

This article presents the results of simulation and fabrication of a new ultra wideband ultra low‐profile blade shape monopole antenna. The antenna is a meanderline loaded by lumped elements with an electrically small ground plane. The reflection coefficient and line of sight gain of antenna is simulated and measured. Results indicate that the antenna has a good performance in 30–500 MHz and deep notches in line‐of‐sight gain are eliminated. Design approaches are described and a new structure is developed. Finally, several key points were expressed for a true measurement procedure in cases that the ground plane is electrically very small. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1695–1699, 2015
Multipath scattering simulation and SAR analysis for a composite model
Authors: Yang Wei , Qi Conghui
Published: April 2015

The physical optics and shooting bouncing ray method are combined to rapidly compute the composite scattering from electrically large three‐dimensional target on a dielectric rough surface. To avoid modeling the infinite rough surface, the image theory and its modification are used to account for the electromagnetic interactions between the target and the infinite ground with very minimal computation resources. Meanwhile, this proposed method can separate the overall multipath scattering into four main components, therefore, it is beneficial to quantify the scattering characteristics for the synthetic aperture radar imagery in this field. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1689–1695, 2015
General design approach of monopole and helix integrated antennas for radio apparatus
Authors: Ren Yu‐Jiun , Ren Jessie , Hwang Huan‐Sheng
Published: April 2015

A design approach of multiband and wideband antennas for radio communication devices is presented. The antenna is consisted of a monopole, a folded loop, and a helix. The fundamental behaviors of the single element and their combinations are analyzed to give desired bandwidths per the mutual coupling between elements. The ground plane dimension and the device thickness are considered. The study has a focus on the UHF and lower microwave range to support most of civilian applications. The presented antenna structure is a good starting point to be familiar with the multiband antenna design as the antenna can be configured to cover a wide frequency range to support cellular telephony, GPS, wireless local networking on so forth. A radio communications device incorporating such antennas is also described. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1718–1723, 2015
Investigation of circular waveguide reflector feeds loaded with shaped dielectric rods
Authors: Qudrat‐E‐Maula Mohammad , Shafai Lotfollah , Pour Zahra A.
Published: April 2015

Circular waveguides loaded with shaped dielectric rods are studied. The waveguide is entirely filled with a dielectric rod, extended from the waveguide aperture and conically shaped to modify the aperture distribution. Its performance as a primary feed is investigated, without and with quarter‐wavelength chokes, to improve sidelobe and backlobe levels. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1568–1573, 2015
A wideband loop‐type antenna
Authors: Moon Sungjin , Lee Hongkoo , Kim Hyeongdong
Published: April 2015

A 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

In 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

We 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

This 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

Compact 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

A 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

This 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

A 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
Fabrication of photo‐cross‐linked polyethyleneimine‐based barriers for CO2 capture
Authors: Eminoğlu Elif Merve , Beypınar Feriha , Kahraman Memet Vezir , Durmuş Ali
Published: April 2015

In this study, first, polyethyleneimine was acrylated and mixed with polyvinyl alcohol solution to prepare photo‐crosslinked polyethyleneimine (PEI)‐based nanofibers by utilizing ultraviolet and electrospinning technique at the same time. For CO2 permeability testing, same formulations were prepared by using solvent casting technique and exposed to ultraviolet light to have polyethyleneimine‐based membrane films. The chemical structures of the nanofibers were characterized by Fourier transform infrared spectroscopy. The thermal properties of nanofibers were examined by thermal gravimetric analysis and differential scanning calorimeter. The morphology of nanofibers was investigated by scanning electron microscopy. CO2 permeabilities of samples were also measured. Copyright © 2015 John Wiley & Sons, Ltd.
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 water on the solubility and diffusivity of hydrocarbons in polyethylene
Authors: Galdámez Jose Román , Jones Adam T. , Danner Ronald P.
Published: April 2015

There are indications in the literature that the devolatilization of some polymers, particularly polyethylene, can be enhanced by the addition of water, generally in the form of steam. In this study three different experimental methods were used with three different solvent–polyethylene systems to evaluate this effect. The results indicated that no measureable differences were found in either the solubility or the diffusivity of the systems between the dry or wet polymer samples. POLYM. ENG. SCI., 55:1459–1462, 2015. © 2015 Society of Plastics Engineers
Population as Auditor of an Election Process in Honduras: The Case of the VotoSocial Crowdsourcing Platform
Authors: Arias Carlos R. , Garcia Jorge , Corpeño Alejandro
Published: April 2015

For a country to become fully democratic, the majority of the population needs to be involved in the politics of that country. This requires people to be aware of what is happening, and to be able to participate in the country's political processes. VotoSocial is a crowdsourcing system launched during the 2013 Honduran government elections. It retrieved the official polling table records in digitized form from the Supreme Electoral Tribunal (the Government's elections authority) and provided them to the Internet community to be counted and the digitizations verified. VotoSocial was thereby able to verify the accuracy of the official polling results. We found no evidence of fraud in the digitization process, but statistical analysis revealed a data behavior usually associated with incremental fraud in an electoral process. VotoSocial shows that social media‐powered crowdsourcing systems can increase a population's political awareness during elections, thus providing a motive to build similar platforms in other countries with political systems marked by electoral fraud.
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

Small 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

Objective

In 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.

Methods

In 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.

Results

The 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.

Conclusions

Although 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.
The induced current strengths and aromatic pathways of heteroporphyrins and their antiaromatic derivatives
Authors: Ren Jie , Bai Fu‐Quan , Zhang Hong‐Xing
Published: April 2015

The magnetically induced current strengths as well as nucleus independent chemical shifts of aromatic heteroporphyrins and antiaromatic 22,24‐dideazaheteroporphyrins have been studied using the density functional theory method. The induced current strengths and pathways are obtained by numerical integration of the induced current densities following the specific chemical bonds. The total induced current strengths of antiaromatic 22,24‐dideazaheteroporphyrins is about 6 nA/T weaker than the one for the heteroporphyrins in absolute value. The substitution of pyrrole NH groups by O and S atoms does not change the total induced current strengths. The induced currents around the molecular macroring split at the heterocycles (pyrrole, furan, and thiophene) into the inner and outer routes. The heteroatoms (N, O, and S) have high resistance and consequently lead to a weaker induced current strength than the one passing the outer route in aromatic heteroporphyrins. For antiaromatic 22,24‐dideazaheteroporphyrins, the heteroatoms enhance the current strength and change the main current pathway into the inner route. The induced current strength following the NH moiety is stronger than the one passing the oxygen moiety of furan ring and the sulfur moiety of the thiophene ring in both heteroporphyrins and 22,24‐dideazaheteroporphyrins. © 2015 Wiley Periodicals, Inc.
Metabolic chemotypes of CITES protected Dalbergia timbers from Africa, Madagascar, and Asia
Authors: McClure Pamela J. , Chavarria Gabriela D. , Espinoza Edgard
Published: April 2015

Rationale

The 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.

Methods

Metabolic 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.

Results

Dalbergia 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.

Conclusions

DART 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

Rationale

Fangchi (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.

Methods

Several 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.

Results

Several 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.

Conclusions

The 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

Rationale

Bacterial 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.

Methods

We 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).

Results

MALDI‐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.

Conclusions

MALDI‐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

Intermittent 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.1350

This article is categorized under:

Computer Science > Machine Learning

Psychology > Learning
The shock of the odd
Authors: Jardine Boris
Published: April 2015

When Linda Dalrymple Henderson's The Fourth Dimension and Non-Euclidean Geometry in Modern Art first appeared in 1983 it generated a lively discussion, most conspicuously in the pages of the journal Leonardo. Here was a book that undermined two of the central tenets of modernist theory: first that developments in art and science were linked not by any real connections or strong form of shared endeavour but by the fact that both partook of the modern spirit or zeitgeist; second, and more specifically, that Einsteinian relativity and cubism were in some way analogous embodiments of that spirit. By relentlessly pursuing the fate of two nineteenth-century developments – the non-Euclidean geometries and higher dimensions of her title – Henderson clearly showed that many of the avant-garde artworks so admired by critics for their formal innovation were at once more literal and more bizarre than anyone had previously suspected. Some were attempts to expound the ‘geometrical occult’ or to engage in multidimensional communion, some projected the enhanced intellect of ‘four-dimensional man’ and others explored the lonely but profound reaches of hyperspace. As she puts it in the ‘Re-introduction’ to this new edition of The Fourth Dimension, ‘these works function as “windows” on an invisible meta-reality of higher dimensions and etherial energies' (p. 27), and, elsewhere, ‘belief in a fourth dimension encouraged artists to depart from visual reality and to reject completely the one-point perspective system that for centuries had portrayed the world as three-dimensional’ (p. 492).
Shaping Public Opinion through Architecture and Urban Design: Perspectives on Ludwig I and His Building Program for a “New Munich”
Authors: Hagen Joshua
Published: April 2015

As the sovereign of a newly fashioned kingdom facing uncertain prospects, King Ludwig I of Bavaria launched a sprawling building program to transform his capital city, Munich. Ludwig believed that the patronage of art and architecture would enhance his political authority and foster a sense of historical legitimacy in his kingdom. He regarded this building program as a way of expressing and impressing on the public his own views of politics, culture, and history, but the associated financial burden became a source of public discontent, a focal point for political opposition, and, ultimately, a factor in Ludwig's later abdication. Public sentiment and scholarly opinion toward Ludwig nevertheless underwent a broad rehabilitation after his reign. Many soon came to view Ludwig's projects as expressions of the monarch's cultural sophistication and generosity, rather than as instruments of political and ideological calculation.
Missing, Lost, and Displaced Children in Postwar Germany: The Great Struggle to Provide for the War's Youngest Victims
Authors: Mouton Michelle
Published: April 2015

In the final months of World War II, more than a million German children took to the roads in search of family and home. Although the majority returned home with little institutional support, hundreds of thousands of other German children could not. Some were orphaned; others remained in camps, children's homes, or foster families in areas that no longer belonged to Germany. Most challenging for authorities were those who were alone and too young to know their own names. This article explores the struggle to locate, identify, and provide for missing, lost, and displaced German children after 1945. It argues that despite a general agreement that children were in peril, Allied denazification policies and the decision by the UN Relief and Rehabilitation Administration (UNRRA) not to help “enemy children” compromised care for children. The division of Germany and the onset of the Cold War further handicapped efforts to aid children by preventing the creation of a unified search service. Yet, despite the many postwar impediments, the effort to care for these children was remarkably successful in the end.
The German Right from Weimar to Hitler: Fragmentation and Coalescence
Authors: Eley Geoff
Published: April 2015

As archival scholarship on National Socialism moved under way during the later 1960s, study of the Right's broader intellectual history relied on a small number of then canonical works—by Klemens von Klemperer (1957), Otto E. Schüddekopf (1960), Fritz Stern (1961), Hans-Joachim Schwierskott (1962), and Kurt Sontheimer (1962), shadowed by Armin Mohler's Die konservative Revolution in Deutschland 1918–1932. Grundriβ ihrer Weltanschauungen (1950)—soon to be joined by George Mosse (1964), Herman Lebovics (1969), and Walter Struve (1973). At this stage, with the exception of Fritz K. Ringer's The Decline of the German Mandarins (1967) and Reinhard Bollmus's study of Alfred Rosenberg's office and its opponents (1970), there was virtually nothing taking a broader social or institutional approach to the contexts of Nazi ideology and the sociology of knowledge under the Third Reich. Gerhard Kratzsch's Kunstwart und Dürerbund. Ein Beitrag zur Geschichte der Gebildeten im Zeitalter des Imperialismus (1969) stood very much alone as a nuanced, archivally researched case study alive to the complex ambivalences of cultural nationalism in the Wilhelmine years.