bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unresolved issues in the preparation and characterization of thermoresponsive microgels
Authors: Pelton Robert 
Published: March 2004

AbstractThe preparation and properties of colloidal thermal responsive microgels based on poly(N‐isopropylacrylamide) are described with an emphasis on the unresolved issues which will impair commercial implementation. The main difficulties are: 1) removal of sol, surfactants and other impurities; 2) obtaining colloidally stable particles less than 50 nm in diameter; 3) synthesis of concentrated, colloidally stable microgel dispersions; 4) accurate measurement of water content; and, 5) control of microgel particle morphology.
Thermoreversible gelation strongly coupled to polymer conformational transition
Authors: Tanaka Fumihiko 
Published: March 2004

AbstractThermoreversible gelation of polymers driven by the coil‐to‐helix transition in chain conformation is theoretically studied. For pairwise association of single helices, there are three fundamental types of self‐assemblies as a result of competition between helix growth and helix association: Type I network (random coils connected by paired short helices), Type II network (helices connected by short random coils) and pairing (pairs of long helices without branching). Two distinct phase diagrams showing sol/gel transition and coil/helix transition are derived for weak and strong association.
Synthesis, characterization and stimuli‐sensitive properties of novel linear and crosslinked polybetaines based on acrylic acid and ethyl 3‐aminocrotonate
Authors: Kudaibergenov Sarkyt E. , Didukh Alexander G. , Zhumadilova Gulmira T. , Koizhaiganova Raushan B. , Bimendina Larisa A. , Jung‐Gyun Noh , Geckeler Kurt E. 
Published: March 2004

AbstractNovel linear and crosslinked polybetaines based on acrylic acid (AA) and ethyl 3‐aminocrotonate (CRO) have been synthesized by a Michael addition reaction followed by radical polymerization. The polymerization of AA and CRO was carried out in bulk, water and organic solvents. The dependence of polymer yield on the molar ratio of monomers and water content was found. Primary attention was paid to linear and crosslinked polybetaines synthesized at equimolar ratio of monomers in the feed. The composition and structure of linear polybetaines was determined by elemental analysis, potentiometric titration, FTIR and NMR spectroscopy. The isoelectric points of linear and crosslinked polybetaines determined by electrophoresis, viscometry and swelling experiments corresponded to pH 2.0‐2.2. The stimuli‐sensitive properties of amphoteric gels were studied as a function of pH, ionic strength, water‐organic solvent mixture, electric, and combined electric and magnetic fields. Appearance of pH gradient within the polyampholyte gel matrix under the externally imposed DC electric field was observed.
Superabsorbent polymer of poly[acrylamide‐co‐(acrylic acid)] by foamed polymerization. I. synthesis and water swelling properties
Authors: Kiatkamjornwong Suda , Wongwatthanasatien Rattana 
Published: March 2004

AbstractSuperabsorbent polymers of acrylamide and acrylic acid were synthesized by foamed polymerization, initiated by ammonium persulfate and N, N, N′, N′‐tetramethylenediamine. The crosslinking agent N, N′‐methylenebisacrylamide, the foaming agent sodium bicarbonate, and a foam stabilizer, a triblock copolymer of polyoxyethylene/polyoxypropylene/polyoxyethylene, were used in the polymerization. The superabsorbent polymer synthesized with an acrylamide/(acrylic acid) ratio of 1:9 by mole at 250 rpm and 45°C for 30 min of polymerization time produced the highest water absorption of 2300 times its dried weight. This article describes the synthetic method and measurements of water absorption.
Let it be: Salvage of exposed hemodialysis grafts with fasciocutaneous island flaps
Authors: Isenberg J. Scott 
Published: March 2004

AbstractContaminated and exposed prosthetic implants have traditionally required surgical explantation. This has been standard treatment, particularly for implants in the central circulation or those bridging major vascular structures, such as hemodialysis grafts. We present our experience in salvaging exposed hemodialysis grafts utilizing regional fascio‐ and septo‐cutaneous flaps. In 5 of 6 cases, graft salvage was achieved, obviating the need for explantation and de novo insertion at another location. In selected instances of hemodialysis graft exposure, wound coverage and graft function can be obtained with regionally based flaps. © 2004 Wiley‐Liss, Inc.
Wideband and high‐gain triple‐offsets‐fed ring‐slot antenna backed by a ground plane
Authors: Jang Yong‐Woong , Arai Hiroyuki 
Published: March 2004

AbstractThe triple‐offsets‐fed ring‐slot antenna backed by a ground plane with large bandwidth and high gain is presented experimentally in this paper. The return loss, radiation pattern, and antenna gain of this configuration are presented. Although the use of a high relative permittivity (εr = 4.3) substrate usually restricts the operation bandwidth, the radiation resistance has a low value, as well. The measured impedance bandwidth is approximately 94.3% (−10 dB ≥ S11). The measured gain of the proposed antenna backed by a ground plane is better than approximately 6 dBi throughout the bandwidth. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 161–163, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20079
PILOT: A fast algorithm for enhanced 3D parasitic capacitance extraction efficiency
Authors: Gope Dipanjan , Jandhyala Vikram 
Published: March 2004

AbstractIntegral‐equation methodologies applied to extract parasitics for board, package, and on‐chip structures involve solving a dense system of equations. In this paper, we present an improved matrix‐compression technique for fast iterative solution of such dense systems, which applies QR decomposition on multilevel oct‐tree‐based interaction sub‐matrices. The regular‐tree structure of the fast‐multipole method and the rank‐revealing QR‐based matrix‐compression scheme are combined in order to achieve superior time and memory efficiency. As is demonstrated by the numerical‐simulation results presented herein, the new algorithm is found to be faster and more memory efficient than both existing QR‐based methods and FastCap. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 169–173, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20083
Analysis of photonic band‐gap (PBG) structures using the FDTD method
Authors: Tong Ming‐Sze , Cheng Min , Lu Yilong , Chen Yinchao , Krozer Viktor , Vahldieck Rüdiger 
Published: March 2004

AbstractIn this paper, a number of photonic band‐gap (PBG) structures, which are formed by periodic circuit elements printed on transmission‐line circuits, are studied by using a well‐known numerical method, the finite‐difference time‐domain (FDTD) method. The results validate the band‐stop filter behavior of these structures, and the computed results generally match well with ones published in the literature. It is also found that the FDTD method is a robust, versatile, and powerful numerical technique to perform such numerical studies. The proposed PBG filter structures may be applied in microwave and communication systems. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 173–177, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20084
Azimuthally symmetric long‐period fiber gratings fabricated with CO2laser
Authors: Oh S. T. , Han W. T. , Paek U. C. , Chung Y. 
Published: March 2004

AbstractTwo methods for fabrication of azimuthally symmetric long‐period fiber gratings (LPFGs) with CO2laser are presented. These methods are based on symmetric exposure of the laser beam and rotation of the fiber, and the measured polarization‐dependent losses (PDL) are comparable to that of the normal fiber. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 188–190, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20088
A widebeam microstrip antenna for intelligent transport system application
Authors: Yin Ying‐Zeng , Zhao Yong‐Jiu , Liu Qi‐Zhong 
Published: March 2004

AbstractA wide‐beam and middle‐gain microstrip antenna for the intelligent transport system (ITS) is demonstrated experimentally and numerically. The results show that a −3‐dB beam width of 105°, a middle gain of 10 dBi, and a bandwidth of about 12% for VSWR less than 2:1 are obtained. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 200–202, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20092
A method for the determination of a distributed FET noise model based on matched‐source noise‐figure measurements
Authors: Maya M. C. , Lázaro A. , Pradell L. 
Published: March 2004

AbstractA new method for the determination of a distributed FET noise model is presented. It is based on the extraction of the intrinsic noise‐correlation matrix of an elemental section of the device from the device's noise figure, measured for only one source‐impedance state at a number of frequency points. Experimental results up to 40 GHz are given. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 221–225, 2004; 2004; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.20099
Scattering analysis for a circular to rectangular T‐junction
Authors: Hwang Keum C. , Eom Hyo J. 
Published: March 2004

AbstractThe reflection and transmission characteristics of a circular‐to‐rectangular single T‐junction are analyzed. The techniques of Fourier transform and mode matching are used for the analysis. An approximate dominant‐mode solution is derived in a closed form. Computations show that our result is numerically efficient and accurate, and thus will be useful for practical application. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 231–234, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20102
Dielectric response of matter with cubic, circular‐cylindrical, and spherical microstructure
Authors: Sihvola Ari , Venermo Jukka , Ylä‐Oijala Pasi 
Published: March 2004

AbstractThe effect of the microstructure of heterogeneous matter on its macroscopic dielectric properties is studied. The basic polarizable elements are allowed to be either homogeneous spheres (which is the classical Lorenz–Lorentz case), cubes, or circular cylinders. Accurate numerical estimates are given for the polarizability of these shapes as functions of the permittivity, and these are applied to estimate the effective permittivity of mixtures where such scatterers are embedded in a background medium. Physical interpretations are given for the behaviour of the dielectric response of these various inclusions. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 245–248, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20106
Compact hairpin‐shaped duplexer using a BMT substrate with high dielectric constant
Authors: Hyung Kwon Koo , Han Sang‐Min , Nahm Shan , Kim Min Han , Kim Young‐Sik 
Published: March 2004

AbstractIn this paper, a compact planar microwave duplexer on a high‐dielectric substrate is proposed. As Ba(Mg1/3Ta2/3)O3 (BMT) has good dielectric performances with a high‐dielectric constant of εr = 23, it is suitable for application on printed circuit boards for compact‐size circuits. The BMT substrate is fabricated using a tape‐casting process; then, metal patterns are screen‐printed upon it and silver pasted. An open‐loop ring‐type duplexer is designed and implemented on the BMT substrate. A size reduction of about 80% is achieved without any degrading duplexer performances, compared with the same one fabricated on a commercial substrate (εr = 6.15). © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 251–253, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20108
Broadband printed π‐shaped monopole antenna for WLAN operation
Authors: Su Saou‐Wen , Wu Chih‐Hsien , Chen Wen‐Shyang , Wong Kin‐Lu 
Published: March 2004

AbstractA broadband printed π‐shaped monopole antenna is presented. The antenna is easily achieved by adding two short vertical strips (one is a feeding strip and one is a short‐circuiting strip) to a long horizontal strip, forming into a π shape with a low profile. This antenna can generate a wide bandwidth (about 29%) formed by two separate, but closely spaced, resonant modes. A prototype well suited for covering the 5.2/5.8‐GHz WLAN bands and operating as an internal antenna for a wireless device is demonstrated. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 269–270, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20113
Noise wave modeling of microwave transistors based on neural networks
Authors: Marković Vera , Pronić Olivera , Marinković Zlatica 
Published: March 2004

AbstractThe noise modeling of microwave FETs based on the noise‐wave representation of a transistor‐intrinsic circuit is considered. Frequency‐dependent noise‐wave temperatures are introduced as empirical model parameters and modeled using neural networks. In this way, online optimization in a circuit simulator is shifted to offline training of neural networks. An example of transistor‐noise modeling for one specified component is shown. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 294–297, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20120
Improving the linearity‐efficiency trade‐off in FET power amplifiers using large‐signal IMD sweet spots
Authors: Malaver Emigdio , García José Angel , Tazón Antonio , Mediavilla Angel 
Published: March 2004

AbstractIn this paper, a device‐level bias‐adaptation technique for improving the linearity‐efficiency trade‐off in Class‐B FET power amplifiers is introduced. The proposed approach uses the low‐current large‐signal intermodulation distortion sweet spot that appears below the VGS pinch‐off voltage as the bias point. A detailed characterization of the sweet‐spot evolution shows that a dynamic dual‐bias adjustment could guarantee, under strong input‐power level variations, low in‐band intermodulation distortion while the amplifier remains working around its highest efficiency value. The proposed technique is validated using an IS‐95 QPSK signal. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 327–331, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20132
Differential development of rabbit embryos derived from parthenogenesis and nuclear transfer
Authors: Liu Ji‐Long , Sung Li‐Ying , Du Fuliang , Julian Marina , Jiang Shie , Barber Michele , Xu Jie , Tian X. Cindy , Yang Xiangzhong 
Published: March 2004

AbstractParthenogenetic development (PA) is often used as a model to investigate activation protocols for nuclear transfer (NT) embryos. The objective of this study was to compare the development, as well as the dynamics of the nuclear materials and microtubules of PA and NT embryos following similar activation treatment. Our results demonstrate that, during parthenogenesis, activation through either electrical pulses or chemical stimulation alone resulted in low cleavage rates and compromised development. A combination of two sets of electrical pulses and a 2‐h‐exposure to chemical activation medium (5 μg/ml cycloheximide (CHX) and 2 mM 6‐dimethylaminopurine (6‐DMAP) in KSOM+0.1% BSA) could effectively activate rabbit oocytes, and resulted in a 99% (n = 73) cleavage rate with greater than 60% (n = 73) developing to blastocysts at day 4. However, the same activation protocol following NT resulted in only 65–72% of oocytes cleaved (depending on donor cell type), with less than 20% developing to the blastocyst stage. The differences observed between NT and PA embryos subjected to the same activation protocol were also evident in terms of the time required for their development to the blastocyst stage, as well as the cell numbers present in blastocysts at day 6. Furthermore, laser confocal microscopy revealed that pronuclear formation in the NT embryos was delayed by comparison to that in the parthenotes. In conclusion, our study suggests that an effective protocol for parthenogenesis cannot promise a comparable outcome for NT embryos. Mol. Reprod. Dev. 68: 58–64, 2004. © 2004 Wiley‐Liss, Inc.
Incidence of apoptosis in clone embryos and improved development by the treatment of donor somatic cells with putative apoptosis inhibitors
Authors: Park E.S. , Hwang W.S. , Jang G. , Cho J.K. , Kang S.K. , Lee B.C. , Han J.Y. , Lim J.M. 
Published: March 2004

AbstractThis study was conducted to promote in vitro‐development of clone embryos by the treatment of donor somatic cells with hemoglobin (Hb) and/or β‐mercaptoethanol (ME), based on the analysis of apoptosis after somatic cell nuclear transfer (SCNT). Prospective, randomized study was conducted and, in vitro‐matured bovine oocytes and fetal fibroblasts were provided for SCNT. In the first series of experiment, embryo apoptosis after SCNT was monitored by a terminal deoxynucleotidyl transferase‐mediated d‐UTP nick end‐labeling assay. As results, apoptosis occurred more (P < 0.05) frequently after SCNT than after in vitro‐fertilization (IVF) of control treatment. Subsequently, donor somatic cells treated with Hb (1 μg/ml) and/or ME (10 μM) were provided for SCNT. Either Hb or ME greatly reduced apoptosis (0.083 ± 0.006 vs. 0.058–0.068 ± 0.005), while combined treatment did not. ME was more promotive than Hb; significant increases were found in morula compaction (86%), cell numbers of blastocyst (131.3 ± 1.3 cells/blastocyst), and inner cell mass (31.9 ± 0.8 cells/blastocyst) cell, and the ratio of inner cell mass to trophectodermal cell numbers (0.24 ± 0.01). In conclusion, the treatment of donor somatic cells with ME or Hb could reduce apoptosis after SCNT, resulting improved preimplantation development. Mol. Reprod. Dev. 68: 65–71, 2004. © 2004 Wiley‐Liss, Inc.
Differential growth, cell proliferation, and apoptosis of mouse embryo in various culture media and in coculture
Authors: Xu Jia‐Sen , Chan Samuel Ting‐Hon , Lee Will W.M. , Lee Kai‐Fai , Yeung William S.B. 
Published: March 2004

AbstractSequential culture and coculture are two methods of improving the development of preimplantation embryos in vitro. Direct comparison of the efficiency of these methods is limited. Proliferation and apoptosis determine the total number of blastomere in preimplantation embryo, which is a sensitive parameter for evaluation of the development of embryo in vitro. In this study, we compared the proliferation and apoptosis of mouse embryo in different culture media, including CZB, KSOM, MTF, G1.2/G2.2 sequential culture media, and in human oviductal cell coculture. Sequential culture using G1.2/G2.2 was superior to KSOM, MTF, and CZB/CZB + G with respect to the formation of 3–4 cell embryos, morula, and blastocyst. G1.2/G2.2 cultured blastocyst had significantly more proliferating blastomeres and higher total cell number per blastocyst than those cultured in KSOM or CZB/CZB + G. Compared to embryos cultured in G1.2/G2.2, embryos cocultured in G1.2/G2.2 hatched more frequently. Cocultured blastocysts also had significantly higher percentage of proliferating cell and lower percentage of apoptotic cell per blastocyst than those cultured in G1.2/G2.2. It was concluded that G1.2/G2.2 facilitated the proliferation of blastomere whilst human oviductal cell coculture suppressed apoptosis in addition to stimulating proliferation of blastomere. Mol. Reprod. Dev. 68: 72–80, 2004. © 2004 Wiley‐Liss, Inc.
Effects of scrotal heating on sperm surface protein PH‐20 expression in sheep
Authors: Fleming Jean S. , Yu Fu , McDonald Robin M. , Meyers Stuart A. , Montgomery Grant W. , Smith John F. , Nicholson Helen D. 
Published: March 2004

AbstractSperm surface protein PH‐20 expression was studied during spermatogenesis in pubertal and adult sheep, using molecular and histological methods. The effects of 24 hr of insulation raising scrotal temperatures to 39°C on PH‐20 expression in ejaculated sheep sperm were also determined. A 282 nt cDNA fragment of ovine PH‐20 was identified in total RNA extracts of sheep testes, which exhibited 76% identity at the nucleotide level with the equivalent region of the human sequence. Ovine PH‐20 mRNA and immunoreactivity were identified only in adult ram testis and not in peri‐pubertal ram testis tubules lacking round spermatids, nor in adult sheep brain, pituitary, heart, spleen, lung, liver, kidney, epididymis, or ovary. Ovine PH‐20 protein was distributed predominantly on the postacrosomal membrane and was also present on the anterior membrane of the sperm head in fresh, unheated sheep semen. Scrotal heating caused a significant, transient decrease in the percentage of PH‐20 immunoreactive sperm, but did not change the pattern of PH‐20 staining on the sperm head. The results strongly suggest that ovine PH‐20 is postmeiotically expressed in haploid germ cells in sheep testis and is arrayed on the membrane of the mature ovine spermatozoon. Scrotal heating appears to have few effects on PH‐20 expression and distribution on ejaculated sperm. Mol. Reprod. Dev. 68: 103–114, 2004. © 2004 Wiley‐Liss, Inc.
Nuclear and cytoskeletal alterations of in vitro matured porcine oocytes under hyperthermia
Authors: Ju Jyh‐Cherng , Tseng Jung‐Kai 
Published: March 2004

AbstractThe effects of heat shock (HS) on the nucleus and cytoskeleton of in vitro matured pig oocytes were examined in this study. Porcine cumulus–oocyte complexes (COCs) were aspirated from 3 to 6 mm diameter follicles and subjected to standard in vitro maturation (IVM) procedures for 42 hr. In Experiment 1, IVM‐derived oocytes were then randomly allocated to different HS treatments at 41.5°C for 0 (control, C0h, n = 101), 1 (HS1h, n = 113), 2 (HS2h, n = 104), and 4 hr (HS4h, n = 111), respectively. An additional control group of oocytes was cultured for 4 hr without HS (C4h, n = 93). Immunocytochemical staining was performed using anti‐tubulins and FITC‐conjugated mouse IgG for microtubule (MT) labeling. The chromatin and microfilaments (MFs) were stained using Hoechst 33342 and rhodamine–phalloidin, respectively. In the severe HS (4 hr), the chromosomes of the MII oocytes became an aggregated chromatin structure and separated into groups. The spindle MTs were completely depolymerized or formed MT arrays. The relative fluorescence intensity (RFI) or amount of the MF structures including transzona processes (TZPs), vitelline ring (VR), and pericytoplasmic MF, were changed in various degrees. The reversibility of these alterations in the chromatin and the cytoskeleton depended on the duration of the HS. In general, abnormalities in the chromosomes, spindle MTs and the percentages of oocytes with pericytoplasmic MTs increased with length of HS treatment. The size of the spindle and the RFI of MFs in the HS oocytes were also altered. The significant changes in the nucleus and the cytoskeleton in porcine oocytes after HS may be associated with reduced development under hyperthermia and, perhaps, with the low pregnancy rates in domestic species during hot seasons. Mol. Reprod. Dev. 68: 125–133, 2004. © 2004 Wiley‐Liss, Inc.