bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation of striatal dopamine transporter imaging with post mortem substantia nigra cell counts
Authors: Kraemmer Julia , Kovacs Gabor G. , Perju‐Dumbrava Laura , Pirker Susanne , Traub‐Weidinger Tatiana , Pirker Walter 
Published: July 2014

AbstractDopamine transporter imaging is widely used for the differential diagnosis of parkinsonism. Only limited data are available on the relationship between striatal dopamine transporter binding and dopaminergic cell loss in the substantia nigra (SN). We analyzed postmortem SN cell counts in patients who had previously undergone dopamine transporter single‐photon emission computed tomography (SPECT). Pathological diagnoses included Parkinson's disease (n = 1), dementia with Lewy bodies (n = 2), multiple system atrophy (n = 1), corticobasal degeneration (n = 2), atypical parkinsonism with multiple pathological conditions (n = 1), Alzheimer's disease (n = 1), and Creutzfeldt‐Jakob disease (n = 1). [123I]β‐CIT SPECT had been performed in all subjects using a standardized protocol on the same triple‐head gamma camera. The density of neuromelanin‐containing and tyrosine hydroxylase–positive substantia nigra neurons/mm2 was evaluated in paraffin‐embedded tissue sections by morphometric methods. Mean disease duration at the time of dopamine transporter imaging was 2.3 years, and the mean interval from imaging to death was 29.3 months (range, 4‐68 months). Visual analysis of dopamine transporter images showed reduced striatal uptake in all seven patients with neurodegenerative parkinsonism, but not in Alzheimer's and Creutzfeldt‐Jakob disease cases. Averaged [(right+left)/2] striatal uptake was highly correlated with averaged SN cell counts (rs = 0.98, P < 0.0005 for neuromelanin‐ and rs = 0.96, P < 0.0005 for tyrosine hydroxylase–positive cells). Similar strong correlations were found in separate analyses for the right and left sides. Striatal dopamine transporter binding highly correlated with postmortem SN cell counts, confirming the validity of dopamine transporter imaging as an excellent in vivo marker of nigrostriatal dopaminergic degeneration. © 2014 International Parkinson and Movement Disorder Society
Delphinidin‐3‐glucoside protects human umbilical vein endothelial cells against oxidized low‐density lipoprotein‐induced injury by autophagy upregulation via the AMPK/SIRT1 signaling pathway
Authors: Jin Xin , Chen Mingliang , Yi Long , Chang Hui , Zhang Ting , Wang Li , Ma Wanqiang , Peng Xiaoli , Zhou Yong , Mi Mantian 
Published: July 2014

ScopeOxidized LDL (oxLDL) induced vascular endothelial cell injury is a key event in the pathogenesis of atherosclerosis (AS). In our previous studies, we showed that delphinidin‐3‐glucoside (Dp), a natural anthocyanin, attenuated oxLDL‐induced injury in human umbilical vein endothelial cells (HUVECs), indicating its potential role in preventing AS. However, the involved mechanism is not fully understood.Methods and resultsVia methyl thiazolyl tetrazolium and flow cytometry assay, we found that Dp‐attenuated oxLDL‐induced cell viability decrease and apoptosis in HUVECs. Depending on confocal microscopy, transmission electron microscopy, and Western blot assay, we found that Dp‐induced autophagy in HUVECs, whereas suppression of autophagy significantly abolished the protective role of Dp against oxLDL‐induced endothelial cell injury. Furthermore, Dp upregulated sirtuin 1 (SIRT1) expression and SIRT1 knockdown notably suppressed Dp‐induced autophagy in HUVECs. Dp also increased the expression of phosphorylated adenosine monophosphate‐activated protein kinase, while adenosine monophosphate‐activated protein kinase (AMPK) knockdown remarkably abolished Dp‐induced SIRT1 expression and subsequent autophagy.ConclusionOur data suggested that Dp protected HUVECs against oxLDL‐induced injury by inducing autophagy via the adenosine monophosphate‐activated protein kinase/SIRT1 signaling pathway. This new finding might shed light to the prevention and therapy of AS.
Extraction and measurement sensitivity improvement of third‐order autocorrelation trace from mixed autocorrelations
Authors: Wei Yizhen , Gao Shiming 
Published: July 2014

ABSTRACTA valuable insight is presented on obtaining high‐sensitivity third‐order autocorrelation trace in the wavelength and power regimes where both two‐ and three‐photon absorption of the detector should be considered. Theoretical analysis and experimental results are provided to discuss the limitations to the measurement sensitivity. By developing a new algorithm of harmonics detection, an approach is also proposed to improve the measurement sensitivity beyond our previous demonstration. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2234–2237, 2014
Ultra wide band vertex truncated printed pentagon monopole antenna
Authors: Ray Kamla Prasan , Thakur S. S. 
Published: July 2014

ABSTRACTPrinted vertex truncated pentagon monopole antenna has been proposed, which yields ultra wide bandwidth. It gives bandwidth (BW) for VSWR ≤ 2 of 1.5–12 GHz. This new configuration has approximate omnidirectional radiation patterns in the azimuth plane throughout the BW. Simulated as well as measured results are presented, which are in agreement. The design equation for calculating the lower band edge frequency has also been derived for the printed pentagon monopole antenna. Systematic explanation has been given using impedance and surface current variations for ultra wide response. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2228–2234, 2014
Comparing phase noise of integer‐N phase‐locked loop of voltage‐controlled and digitally controlled oscillators
Authors: Wu Jian‐Ming , Chou Stephen , Li Simon Cimin , Ho Cheng‐Yu 
Published: July 2014

ABSTRACTThis article compares the phase noise of an integer‐N phase‐locked loop (PLL) obtained using a voltage‐controlled oscillator (VCO) with those obtained using a digitally controlled oscillator (DCO). The cores of both VCO and DCO are single‐ended Clapp oscillators. To select the frequency of oscillation, a conventional analogue control is used in the VCO while a five‐bit digitally controlled circuit is adopted in the DCO. The VCO and DCO are designed and implemented using Agilent's GaAs HEMT ATF55143. Both are used in a PE3335 integer‐N PLL from Peregrine Semiconductor, and the performance of each is investigated in terms of phase noise. Careful comparison reveals that the integer‐N PLL with the DCO has a 7 dBc/Hz lower phase noise inside the loop bandwidth than the integer‐N PLL with the VCO. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2226–2228, 2014
Design and implementation of squared and octagonal W‐band CMOS marchand baluns for W‐band communication systems
Authors: Lin Yo‐Sheng , Liu Feng‐Chen , Wen Wei‐Chen 
Published: July 2014

ABSTRACTAn enhanced squared and an enhanced octagonal W‐band CMOS Marchand baluns for direct‐conversion transceiver are reported. These Marchand baluns can be applied to an up‐conversion mixer for converting the single local oscillator input signal into differential signal, and converting the differential RF output signal to single signal. They can also be applied to a subharmonic down‐conversion mixer for converting the single RF input signal into differential signal. Instead of the traditional Marchand balun structure that uses three sections of thin (0.53 μm) M5 interconnection lines (underneath the thick (2.34 μm) M6 main structure), the proposed balun structures use only one section of thin M5 interconnection line to improve S21 and S31. The squared Marchand balun occupies a small chip area of 0.0313 mm2, and achieves S21 of −4.19 to −4.53 dB, S31 of −4.28 ∼ to −4.42 dB, magnitude of amplitude imbalance (MAI) smaller than 0.11 dB and deviation of phase difference (DPD) smaller than 4.3° for frequencies 75 ∼ −85 GHz. The octagonal Marchand balun occupies a small chip area of 0.0288 mm2, and achieves S21 of −4.56 to −5.03 dB, S31 of −4.56 to −4.86 dB, MAI smaller than 0.18 dB and DPD smaller than 2° for frequencies 75–85 GHz. The state‐of‐the‐art results of these proposed baluns indicate that they are suitable for W‐band communication systems. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2205–2211, 2014
A 10.5‐GHz divide‐by‐3 injection‐locked frequency divider with enhanced locking range by even‐harmonic phase tuning in 0.18 μm BiCMOS
Authors: Lee Sanghun , Jang Sunhwan , Nguyen Cam 
Published: July 2014

ABSTRACTA fully integrated 10.5‐GHz divide‐by‐3 (1/3) injection‐locked frequency divider (ILFD) that can provide extra locking range is presented. The ILFD consists of a previously measured on‐chip 10.5‐GHz voltage controlled oscillator (VCO) functioning as an injection source, a 1/3 ILFD core, and an output inverter buffer. A phase tuner implemented using an asymmetric inductor is proposed to increase the locking range through even‐harmonic phase tuning. With a fixed internal injection signal power of only −18 dBm, a 25% enhancement in the locking range from 12 to 15 MHz is achieved with the proposed phase tuning. The proposed even‐harmonic phase tuning can be used to provide extra locking range to those achieved by other techniques. The proposed integrated 1/3 ILFD has a frequency tuning range of 3.3–4.2 GHz. It is realized using a 0.18‐μm BiCMOS process, occupies 0.6 mm × 0.7 mm, and consumes 10.6 mA while the ILFD core alone only consumes 6.15 mA from 1.8‐V supply voltage. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2249–2252, 2014
Optimal size of uniform aperture for near‐field penetration through lossy medium
Authors: Razavi Aidin , Yang Jian 
Published: July 2014

ABSTRACTWe present our investigations on the optimal size of uniform antenna aperture for the maximum near‐field penetration of microwave signals through lossy materials. Penetration ability of an antenna through a certain depth in a lossy material depends on how much the radiated power from the antenna is focused at that depth. A figure of merit, the near‐field 3 dB beam radius, is used to define this focusing. Empirical formula to calculate the minimum 3 dB radius and its location are provided in the article. Verification of the results has been carried out by simulations using a commercial electromagnetic solver. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2301–2304, 2014
Designs of spiral slot antennas with dual‐frequency operation
Authors: Row Jeen‐Sheen , Chen Li‐Ting 
Published: July 2014

ABSTRACTDual‐frequency slot antennas with different polarization combinations are studied in this article. The antenna is a single‐arm spiral slot fed by a microstrip line. A comparison between the circular polarization (CP) design methods of a shorted ring slot antenna and a spiral slot antenna is first made. By the comparison results, a design for dual‐frequency CP spiral slot antennas is then drawn. Moreover, it is found that, by rotating the spiral slot, the polarization senses at the two operating frequencies can be varied among three different combinations, including (left‐handed CP, right‐handed CP), (right‐handed CP, left‐handed CP), and (linear polarization, linear polarization). Simulation and experimental results for the performances of the antenna operating at each polarization combination are shown in detail. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2294–2297, 2014
Low‐ringing and reduced‐cost step recovery diode based UWB pulse generators for GPR applications
Authors: Kamal Athar , Bhattacharya Amitabha , Tamrakar Maruti , Roy Chayan 
Published: July 2014

ABSTRACTLow‐ringing and reduced‐cost pulse generators for ultrawideband applications using step recovery diode (SRD) have been reported in this article. The circuits generate Gaussian pulses of 170 ps pulse width and a minimal ringing of −22 dB and monocycles of 401 ps duration and high fractional bandwidth of 162%. Cost‐reduction is mainly attributed to the resistive attenuator and single SRD used. Negligible change in circuits' performance was witnessed for repetition rate from 1 to 100 MHz which makes it apt for low to medium range ground penetrating radar applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2289–2294, 2014
SAR study of antennas in wireless communication terminals
Authors: Shi Yan , Sun Hao , Liang Chang‐Hong 
Published: July 2014

ABSTRACTA new normalized evaluation method has been proposed to compare specific absorption rates (SARs) of four representative terminal antennas at wireless communication LTE band 7 including loop antenna, monopole antenna, planar inverted‐f antenna (PIFA), and zeroth‐order resonant (ZOR) antenna based on the composite left‐ and right‐hands transmission line. According to analyses of the effects of human tissue on antenna performance, input power is normalized by return loss and radiation efficiency of terminal antennas. Simulation and measurement results show that the normalized SARs of four antennas for 4G USB dongle application are reasonably ranked in order from small to large as PIFA, ZOR antenna, loop antenna, monopole antenna, which means that PIFA has most homogeneous near‐zone power distribution, whereas monopole antenna has the worst one among four antennas. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2361–2365, 2014
Design of a high‐gain ultra‐wideband planar dipole antenna using LC tanks, chip resistors, and dual‐layer frequency selective surface
Authors: Shadrokh Shahin , Yu Yiqiang , Jolani Farid , Chen Zhizhang 
Published: July 2014

AbstractIn this article, a low‐profile, high‐gain, ultra‐wideband (UWB) planar dipole antenna is presented for radar imaging applications. The antenna is loaded with open complementary double concentric split‐hexagonal‐ring resonators (LC tank) and chip resistors, and backed with a novel double‐layer frequency selective surface reflector for gain enhancement. A broadband microstrip to parallel‐plate transformer is designed as the feeding structure of the antenna to provide impedance matching and balanced‐to‐unbalanced transition. The measurement results show the proposed antenna operates over the frequency bandwidth of 0.65–3.8 GHz with S11< −10 dB (VSWR) and smooth gains in the range of 6.2–9 dBi. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2369–2373, 2014
Experimental and simulated study of dual‐band chiral metamaterials with strong optical activity
Authors: Min‐Hua Li , Lin‐yan Guo , He‐Lin Yang 
Published: July 2014

ABSTRACTA dual‐band planar chiral metamaterial (CMM) with strong optical activity is experimentally constructed by twisted split rings. Resonant frequencies with strong optical activity are around 7.9 and 8.9 GHz for right circularly polarized (RCP) and 9.95 and 10.9 GHz for left circularly polarized (LCP) wave, respectively. In particular, the two independent eigenfrequencies depend sensitively on the twist angles, which can offer a convenient approach in building multiband or tunable CMMs. With the twist angle increased from 0° to 90°, the resonant frequencies play an obvious blueshift for RCP wave and redshift for LCP wave, respectively. Current distributions are also studied, which demonstrate that the observed resonances are linked to the excitation of multimodal standing current waves. Microwave experiments are performed to successfully realize these ideas and results are in good agreement with the numerical results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2381–2385, 2014
Electromagnetic analysis of graphene based tunable waveguide resonators
Authors: Ilić Andjelija Ž. , Budimir Djuradj 
Published: July 2014

ABSTRACTThe electromagnetic analysis of the proposed graphene based tunable waveguide resonators for submillimeter‐wave applications is presented. Simple design based on the conventional E‐plane resonator is considered. The desired tunability up to 5% is provided by the change of the effective resonator length. Simulation results are presented to validate the argument. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2385–2388, 2014
Wavelength tunable single longitudinal mode fiber laser pinned to 25 GHz spacing
Authors: Yang Chengliang , Xia Li , Wang Yuanwu , Liu Deming 
Published: July 2014

ABSTRACTA wavelength tunable single longitudinal mode (SLM) fiber laser is demonstrated with a high power Er‐Yb codoped fiber amplifier (EDFA) used as gain medium. A fiber Fabry‐Perot filter and a bandpass filter ensure single wavelength lasing. To realize SLM operation, a section of unpumped EDF in a Sagnac loop is adopted as a saturable absorber, which results in a self‐induced FBG (frequency band gap) with an ultranarrow bandwidth. The proposed laser is very stable and in SLM operation. The signal to noise ratio is measured about 65 dB. The output laser has a tuning range over 30 nm from 1535 to1565 nm. The tuning step of the proposed laser is 0.20 nm pinned to the ITU grid. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2404–2406, 2014
An X‐band substrate integrated waveguide attenuator
Authors: Eom Dong‐Sik , Lee Hai‐Young 
Published: July 2014

ABSTRACTAn X‐band substrate integrated waveguide (SIW) attenuator is presented for the first time. To gain the desired attenuation level, a resistive π‐network was structured using standard surface‐mount device resistors while retaining a predefined mode transition and impedance matching condition. The attenuator prototype features the measure of attenuation level (−1, −3, and −5dB) across 8.04–11.12 GHz frequency range. The attenuator may contribute to design of a genuine SIW circuit. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2446–2449, 2014
Adaptive grouping for the higher‐order multilevel fast multipole method
Authors: Borries Oscar , Jørgensen Erik , Meincke Peter , Hansen Per Christian 
Published: July 2014

ABSTRACTAn alternative parameter‐free adaptive approach for the grouping of the basis function patterns in the multilevel fast multipole method is presented, yielding significant memory savings compared to the traditional Octree grouping for most discretizations, particularly when using higher‐order basis functions. Results from both a uniformly and nonuniformly meshed scatterer are presented, showing how the technique is worthwhile even for regular meshes, and demonstrating that there is no loss of accuracy in spite of the large reduction in memory requirements and the relatively low computational cost. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2451–2456, 2014
Liquid metal patch antenna and antenna array for WLAN applications
Authors: Semkin Vasilii , Platonov Oleg , Kyrö Mikko , Räisänen Antti V. 
Published: July 2014

ABSTRACTThe concept of a reconfigurable patch antenna array is presented in this article. Configurability is achieved using liquid metal alloy which fills necessary milled channels in the antenna structure. A single patch antenna and three patch antenna array are simulated and measured in this work. Matching and radiation properties in the frequency range from 4 to 10 GHz are presented. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2462–2464, 2014
Facile synthesis of high‐molecular‐weight acid‐labile polypeptides using urethane derivatives
Authors: Wong Shirley , Kwon Young Jik 
Published: July 2014

ABSTRACTPolypeptides have received noticeable attention in the biomedical field due to their structural versatility and biomimetic properties. Particularly, polypeptides that are responsive to biological stimuli, such as mildly acidic extracellular and intracellular conditions, have great potential as delivery carriers for therapeutics. However, synthesis of high‐molecular‐weight acid‐labile peptides is often daunting due to highly restrictive polymerization conditions and limitations in preserving acid‐degradable functional groups. For instance, the popular N‐carboxyanhydride (NCA) ring‐opening polymerization (ROP) is efficient, but acid‐labile NCA monomers are difficult to synthesize and store. In this study, acid‐labile polypeptides with high molecular weights were synthesized under mild, permissive conditions using carboxylated urethane derivative monomers which are stable for ease of handling. The polymerization was successful in various organic solvents at room temperature, and did not require additional energy or initiation to drive the formation of NCA intermediates. The polymerization was also rapid enough to be independent of inert atmosphere. The strategy explored here to synthesize high‐molecular‐weight acid‐labile polypeptides offers significant advantages including facile synthesis of acid‐labile urethane derivative monomers that are stable, even in contact with moisture, and fast polymerization under easily achievable conditions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 280–286
Pharmacokinetics and toxicology of a fibroblast activation protein (FAP)‐activated prodrug in murine xenograft models of human cancer
Authors: Brennen W. Nathaniel , Rosen D. Marc , Chaux Alcides , Netto George J. , Isaacs John T. , Denmeade Samuel R. 
Published: July 2014

BACKGROUNDAs carcinoma progresses, the stroma undergoes a variety of phenotypic changes, including the presence of carcinoma‐associated fibroblasts (CAFs) that express fibroblast activation protein (FAP). FAP is a post‐prolyl endopeptidase whose expression in a healthy adult is largely restricted to the cancer‐associated stroma. FAP‐targeted prodrugs with a 100‐fold greater therapeutic window over the parent compound were previously generated.METHODSProdrugs and non‐cleavable controls were incubated in the presence of FAP. Plasma and tumor half‐lives (t1/2) of the full‐length and active forms of the prodrugs were determined using LCMS. Biodistribution studies of prodrug activation were performed. Histopathological analysis of tissues from treated animals were compared to vehicle‐treated controls. Toxicity and efficacy studies were performed in human breast (MDA‐MB‐231 and MCF‐7) and prostate (LNCaP) cancer xenografts models.RESULTSThese FAP‐activated prodrugs have a significantly slower clearance from tumor tissue than the circulation (∼12 vs. ∼4.5 hr). Micromolar concentrations of active drug persist in the tumor. Active drug is detected in non‐target tissues; however, histopathologic evaluation reveals no evidence of drug‐induced toxicity. A FAP‐activated prodrug (ERGETGP‐S12ADT) inhibits tumor growth in multiple human breast and prostate cancer xenograft models. The anti‐tumor effect is comparable to that observed with docetaxel, but results in significantly less toxicity.CONCLUSIONFAP‐activated prodrugs are a viable strategy for the management of prostate and other cancers. These prodrugs exhibit less toxicity than a commonly used chemotherapeutic agent. Further refinement of the FAP cleavage site for greater specificity may reduce prodrug activation in non‐target tissues and enhance clinical benefit. Prostate 74: 1308–1319, 2014. © 2014 Wiley Periodicals, Inc.