bluuebunny/crossref_metadata_2025 huggingface dataset:
Compact pentagon microstrip antenna with circular polarization
Authors: Chen Horng‐Dean , Chen Wen‐Shyang
Published: August 2002

By embedding a group of four bent slots in the equilateral‐pentagon patch and introducing a peripheral cut at the patch boundary, a compact pentagon microstrip antenna with circularly polarized (CP) operation can be implemented using a probe feed. Results have been obtained that, for a given operation frequency, the antenna size reduction of the proposed design can be as large as 41% as compared to the regular‐size CP equilateral‐pentagon microstrip antenna. Details of the design considerations are described, and measured CP characteristics are presented. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 370–372, 2001.
Dual‐baseband and RF modulation scheme for Gbit/s heterogeneous fiber–wireless access networks
Authors: Martinez A. , Marti J. , Polo V.
Published: August 2002

A dual‐modulation scheme to simultaneously transmit broadband signals on both baseband (BB) and millimeter‐wave RF carriers over optical fiber links is proposed and demonstrated. The key parameters of this technique are optimized for achieving the best performance in Gbit/s wireless millimeter‐wave fiber networks. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 372–374, 2001.
A simplified analog group delay equalizer and its performance for point‐to‐point cochannel radio relay system applications
Authors: Suh Kyoung‐Whoan
Published: August 2002

The implementation of a simplified analog group delay equalizer is presented for a high‐capacity SDH radio relay system. It provides good performance in terms of simple hardware and easy tuning, and the measured results are in good agreement with the simulated ones. To suggest practical applications, experimental results are illustrated here for a cochannel 64‐QAM radio relay system. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 397–400, 2001.
Propagation of power through highly bent parabolic cylindrical waveguides
Authors: Choudhury P. K.
Published: August 2002

A rigorous analytical estimation is made of the propagation of power through a highly bent step‐index parabolic cylindrical waveguide (PCW), the bending being across the direction of electromagnetic (EM) wave propagation. The scalar field approximation is employed for the analytical treatment. The general expression for power in the waveguide core is derived under the condition of vanishing refractive‐index (RI) difference of the guide. The power patterns are shown for two different waveguide dimensions, and corresponding to different azimuthal modal indexes. The presented analysis is rigorous in the sense that no approximation is used to determine the representative functions for fields. It is found that an almost equal amount of power is carried by the bunched modes in thinner PCWs, and this feature affects guides having a higher thickness where the modes are less tightly bunched together. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 407–410, 2001.
Geometrical classifications of 0<K<1 and −1<K<0 for conditionally stable amplifiers
Authors: Meng C. C. , Ni H. Y.
Published: August 2002

The geometrical interpretation of 0<K<1 and −1<K<0 for conditionally stable (|K|<1) amplifiers is identified on the Smith chart with the help of B‐, D‐, and E‐factors. A simultaneous conjugate match is impossible for conditionally stable designs, but a conditionally stable amplifier with 0<K<1 can be designed with single‐sided matching. There are totally eight geometrical situations for conditional stable amplifiers in terms of K‐, B‐, D‐, and E‐factors. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 18–20, 2001.
Cross‐ridge trough rectangular waveguide
Authors: Klymyshyn David M. , Qiu Dai , Pramanick Protap
Published: August 2002

A new ridge trough rectangular waveguide loaded with a horizontal “cross” ridge is proposed and analyzed using the finite‐element method. Analysis predicts a dramatic increase in the fundamental‐mode cutoff wavelength performance and high bandwidth. The waveguide is attractive for emerging microwave and millimeter‐wave applications requiring highly integrated, compact structures. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 20–23, 2001.
Regular circular and compact semicircular patch antennas with a T‐probe feeding
Authors: Guo Y. X. , Luk K. M. , Lee K. F.
Published: August 2002

Wideband T‐probe proximity‐fed regular circular and compact semicircular patch antennas are proposed in this paper. For the regular circular patch antenna, using a foam layer of thickness ∼0.13λ0 as a supported substrate, an impedance bandwidth of 35% and a gain of over 8.0 dBi have been obtained. For the compact semicircular patch antenna, an impedance bandwidth of 56% and a gain of over 5.4 dBi are achieved with the same substrate thickness. The far‐field patterns are stable across the passband. Experimental and computed results based on the finite‐difference time‐domain method are provided. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 68–71, 2001.
Analysis of switching performance of the semiconductor optical amplifier–Mach–Zehnder interferometer based all‐optical add/drop multiplexer
Authors: Yongpeng Zhao , Peida Ye
Published: August 2002

The extinction ratio, switching contrast, and amplitude modulation (AM) characteristics of a semiconductor optical amplifier (SOA) based Mach–Zehnder interferometer (MZI) as an all‐optical add–drop multiplexer (AO–ADM) are analyzed. It shows that the switching performance can be improved by optimizing the splitting ratio of the couplers and the relative small‐signal gain of the two SOAs. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 77–81, 2001.
A phase II study of homoharringtonine for the treatment of children with refractory or recurrent acute myelogenous leukemia: A pediatric oncology group study
Authors: Bell Beverly A. , Chang Myron N. , Weinstein Howard J.
Published: August 2002

Background

Homoharringtonine (HHT) is a plant alkaloid that is derived from a Chinese evergreen tree. Its mechanism of action is thought to be by inhibition of protein, DNA, and RNA synthesis by inhibition of chain initiation. The treatment of acute myelogenous leukemia (AML) in children, has been hampered by few new effective agents developed in the past 30 years. Significant numbers of children still die of this disease. The purpose of this study is to evaluate the efficacy and toxicity of HHT for the therapy of refractory AML in children.

Procedure

Patients entered the study and were treated with HHT 7mg/m2/day for 10 days. The cycles could be repeated every 21 days depending on recovery from myelosuppression.

Results

Thirty‐seven patients entered the study, with twenty‐eight evaluable for response. Complete response was obtained in four and a partial response in one (response rate 5/28 = 18%). Significant toxicities included prolonged severe myelosuppression in all responsive patients and neuropathogenic pain in two patients. The median duration of response was 62 days with a range of 28–126 days.

Conclusions

HHT has activity against chemotherapy resistant AML in children, with tolerable toxicity. This agent warrants further clinical evaluation in combination with other agents or perhaps biologic response modifiers which will hopefully lead to useful therapeutic options. Med Pediatr Oncol 2001;37:103–107. © 2001 Wiley‐Liss, Inc.
Delayed nausea and vomiting in children receiving antineoplastics
Authors: Dupuis L. Lee , Lau Robert , Greenberg Mark L.
Published: August 2002

Background

The nature and prevalence of delayed antineoplastic‐induced nausea and vomiting have not been well‐described in children. This study describes the extent of delayed nausea and vomiting in children receiving antineoplastic agents as well as the drug therapies initiated in an attempt to prevent or manage it.

Procedure

All children receiving antineoplastics were eligible for study entry. The date and time of each emetic episode were recorded on each day antineoplastics were given and for 3 days thereafter. Nausea was self‐assessed daily by children who were older than 3 years and were not developmentally delayed. Diet was also assessed daily. The emetic response, median nausea rating and median diet achieved were described.

Results

The emetic response of 124 children who received 174 antineoplastic cycles was evaluated. Most cycles (137/174;79%) were not associated with delayed vomiting. Cycles which included cisplatin, carboplatin, or cyclophosphamide; involved antineoplastic therapy given over 2 or more consecutive days; or were accompanied by vomiting during the acute phase were associated with a significantly higher incidence of delayed vomiting. Moderate to severe nausea was reported on 58% (267/459) of study days. No antiemetics were given on most study days (412/522;79%); nevertheless, most of the study days (381/412;93%) which were unaccompanied by antiemetic support during the delayed phase were completely free from vomiting. Antiemetics were most often given as single agents (ondansetron: 54 study days; dimenhydrinate: 17 study days; dexamethasone: 6 study days). Diet was largely unaffected during the study period.

Conclusions

Antineoplastic‐induced delayed nausea and vomiting may be less prevalent in children than in adults. Routine antiemetic administration during the delayed phase may not be warranted in all patients. Med Pediatr Oncol 2001;37:115–121. © 2001 Wiley‐Liss, Inc.
Painful peripheral neuropathy after treatment with high‐dose ifosfamide
Authors: Frisk Per , Stålberg Erik , Strömberg Bo , Jakobson Åke
Published: August 2002

Background

Ifosfamide is successfully employed in the treatment of bone and soft tissue sarcomas in children and young adults. Used at high doses (HDI) the drug may cause severe multiorgan toxicity. Peripheral neuropathy is a less well‐known side effect that may limit its use. We describe a 16‐year‐old girl with a Ewing sarcoma who was given post‐operative treatment with HDI (15 mg/m2 infused over 5 days). After the second course she experienced paresthesias in both feet. After the third course she developed signs of severe toxicity in the CNS, kidneys, heart, and severe pain in her feet.

Procedure

Neurologic and neurophysiologic investigations, including neurographic studies of motor and sensory nerves, EMG, and thermotest, were performed in the acute phase and after 6 and 21 months, respectively. Renal and cardiac function was also assessed.

Results

She developed generalized weakness of the arms and legs and an extremely painful hyperesthesia of the soles. The symptoms improved gradually during follow‐up but remained to some extent even after more than 2 years. Serial neurophysiologic investigations indicated classical signs of axonal neuropathy, which tended to improve during follow‐up. After 18 months the glomerular filtration rate and the effective renal plasma flow were 30 and 12% of normal, respectively, while other organ functions had returned to baseline.

Conclusions

Symptoms of peripheral neuropathy after HDI may herald severe multiorgan toxicity, if continued. Early administration of anesthetics through the intrathecal route should be considered in case of ifosfamide‐induced painful peripheral neuropathy. Med Pediatr Oncol 2001;37:379–382. © 2001 Wiley‐Liss, Inc.
Cancer in older adolescents and young adults: Epidemiology, diagnosis, treatment, survival, and importance of clinical trials
Authors: Bleyer W. Archie
Published: August 2002

Cancer in adolescents and young adults has unique features in addition to the special medical, physical, psychological, and social needs of patients in this age group. The spectrum of malignant diseases is different from that in any other period in life, and it is strikingly different from the pattern in older persons. More people 15–25 years of age are diagnosed to have cancer than during the first 15 years of life. During the last 25 years, the incidence of cancer in this age range has increased faster while the increase in their cancer survival rates has been significantly lower than in younger or older patients, especially in comparison to results of the national pediatric cooperative cancer groups. Thus the 5‐year outcome in 15–19 year olds with leukemias and sarcomas is not only worse than in younger patients, but also lower in this population at large than in patients of the same age treated at Children's Cancer Group institutions. In the United States, only ∼5% of 15–25 year olds with cancer are entered onto clinical trials, in contrast to 60–65% of younger patients. Thus, cancer during adolescence and early adult life is an underestimated challenge that merits specific resources, solutions, and an international focus. Med Pediatr Oncol 2002;38:1–10. © 2002 Wiley‐Liss, Inc.
Placental site trophoblastic tumor (PSTT) in mother and child: First report of PSTT in infancy
Authors: Monclair Tom , Abeler Vera M. , Kærn Janne , Walaas Lisa , Zeller Bernward , Hilstrøm Carsten
Published: August 2002

Background

To the authors' knowledge, placental site trophoblastic tumors occurring simultaneously in mother and infant have not previously been reported.

Procedure

The clinicopathologic features of metastatic placental site trophoblastic tumor in a mother and her 4‐month‐old son are described.

Results

The disease in the infant was aggressive, and he died in multiorgan failure within 5 weeks of hospital admission. Autopsy showed widespread metastases to liver, lungs, pleura, kidney, mesentery and lymph nodes. The mother, who had a uterine tumor and lung metastases, was treated with chemotherapy and hysterectomy and has no evidence of disease 26 months post‐treatment.

Conclusions

This report shows that placental site trophoblastic tumors can metastasize in both mother and child. Med Pediatr Oncol 2002;38:187–191. © 2002 Wiley‐Liss, Inc.
Biology and treatment of familial hemophagocytic lymphohistiocytosis: Importance of perforin in lymphocyte‐mediated cytotoxicity and triggering of apoptosis
Authors: Henter Jan‐Inge
Published: August 2002

Familial hemophagocytic lymphohistiocytosis (FHL) is, without treatment, an invariably fatal disease of infancy and early childhood characterized by fever, hepatosplenomegaly, pancytopenia, and a widespread accumulation of T‐lymphocytes and macrophages. During recent years, the diagnosis and the survival as well as the understanding of the disease have improved dramatically. Recent studies suggest that FHL is caused by impaired lymphocyt e‐mediated cytotoxicity and defective triggering of apoptosis, and that the symptoms are mediated by a pro‐inflammatory hypercytokinemia. Moreover, specific genetic alterations, mutations in the perforin gene, have been revealed in FHL patients. Perforin, which normally is secreted from cytotoxic T‐lymphocytes and natural killer (NK) cells upon conjugation between effector and target cells, is able to insert into the membrane of the target cell. It there polymerizes to form a cell death‐inducing pore through which toxic granzymes may enter the cell and trigger apoptosis. The establishment of perforin deficiency as a cause of the rapidly fatal disease FHL has demonstrated the essential role of perforin in human immune homeostasis. Med. Pediatr. Oncol. 2002;38:305–309. © 2002 Wiley‐Liss, Inc.
Complete assignment of 1H and 13C NMR spectra of new pentacyclic triterpene acid benzyl esters
Authors: Weis Robert , Seebacher Werner
Published: August 2002

Complete assignments of 1H and 13C NMR chemical shifts for newly synthesized benzyl esters of oleanolic, ursolic and crataegolic acid based on DEPT, HSQC, HMBC, COSY, TOCSY, NOE and ROESY experiments are reported. Copyright © 2002 John Wiley & Sons, Ltd.
Structure of an unexpected trimer from the reaction of ageratochromene II with aluminum chloride
Authors: Chu Changhu , Hu Jiehan , XU Tao , Xiao Hongbin , Liang Xinmiao
Published: August 2002

A new trimer from the reaction of ageratochromene [1] (6,7‐dimethoxy‐2,2‐dimethyl‐1‐benzopyran) with anhydrous aluminum chloride was shown to be 3,4‐dihydro‐6,7‐dimethoxy‐2,2‐dimethyl‐3‐(6′,7′‐dimethoxy‐2′,2′‐dimethyl‐2H‐1‐benzopyran‐4′‐yl)‐4‐(3′,4′‐dihydro‐6′, 7′‐dimethoxy‐2′,2′‐dimethyl‐2H‐1‐benzopyran‐3′‐yl)‐ 2H‐1‐benzopyran. Its structure was confirmed by NMR (1H, 13C, DEPT‐135. COSY, HMBC, HSQC, TOCSY and NOESY), IR, mass spectra and elemental analysis. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and spectral study of (2R,11R)‐2,11‐bis{[(2‐methoxyethoxy)methoxy]methyl}‐1,10‐dibenzyl‐4,7,13,16‐tetraoxa‐1,10‐diaza‐cyclooctadecane
Authors: Joly Jean‐Pierre , Walker Olivier , Mutzenhardt Pierre
Published: August 2002

A new C2‐symmetric chiral lariat ether has been prepared by 1 : 1 cyclocondensation of a contrafunctional amine easily obtained from L‐serine. Its 1H and 13C spectra were completely assigned using the two‐dimensional gradient enhanced one‐bond (HMQC) and multiple‐bond (HMBC) heteronuclear techniques together with the homonuclear DQF COSY correlation technique. Copyright © 2001 John Wiley & Sons, Ltd.
Reassignment of NMR spectra and conformational study of the sesquiterpene lactone goyazensolide
Authors: Perry Katia S. P. , Miguez Eduardo , de Amorim Mauro B. , Boaventura Maria Amelia D. , da Silva Antonio Jorge R.
Published: August 2002

We describe the reassignment of 13C NMR signals of goyazensolide based upon 1D and 2D techniques, and discuss its conformation and stereochemistry as obtained from the analysis of its proton spin–spin coupling constants, NOE measurements and molecular mechanics calculations using MM3* force field. Copyright © 2001 John Wiley & Sons, Ltd.
Sequential resonance assignment from two‐dimensional inter‐ and intra‐residue 15N–1H correlation spectra
Authors: Perttu Permi , Arto Annila
Published: August 2002

Sequential assignment of amide resonances in proteins and peptides can conveniently be derived from two‐dimensional inter‐residue 15Ni–1HN(i−1) and intra‐residue 15Ni–1HNi correlation spectra. The inter‐residue 15Ni–1HN(i−1) correlation spectrum is generated by recording the 15Ni frequency evolution indirectly and subsequently transferring the magnetization to 1HN(i−1) of the preceding residue for direct detection. The flow of coherence is established by the (H)N(COCAHA)‐TOCSY pulse sequence. Following the path from intra‐residue correlation via inter‐residue correlation to the next intra‐residue correlation results in sequential assignment in two dimensions. This kind of assignment protocol is most amenable to re‐establishing sequential assignments of target proteins perturbed by binding of ligands or alternatively signals of peptide ligands can be traced in studies of structure–function relationships by NMR. Copyright © 2001 John Wiley & Sons, Ltd.
Cyclodimerization of α,β–α′,β′‐unsaturated ketones promoted by samarium diiodide. Complete assignment of the 1H and 13C NMR spectra of hydroxycyclopentylpropenone derivatives
Authors: Lagadec Ronan Le , Chávez María Isabel , Rubio Laura , Cabrera Armando
Published: August 2002

The 1H and 13C NMR chemical shift assignments of hydroxycyclopentylpropenone derivatives, prepared by a highly selective reaction between samarium(II) iodide and unsaturated ketones, are described. Two‐dimensional shift‐correlated experiments (COSY, HMBC, HMQC, NOESY) were used to assign the chemical shifts completely and unambiguously. Copyright © 2001 John Wiley & Sons, Ltd.
Proton, carbon and nitrogen NMR spectroscopic characterization of some bi‐ and trihetaryl compounds
Authors: Hametner Christian , Hattinger Gregor , Röhrling Jürgen , Fröhlich Johannes , Stanetty Peter , Mihovilovic Marko D.
Published: August 2002

The 1H, 13C, and 15N shifts of 10 nitrogen‐containing bi‐ and triaryls are reported, including the coupling constants of the fluoro substituents with all nuclei. The proton and carbon resonances of the hetaryl structures are completely assigned. Copyright © 2001 John Wiley & Sons, Ltd.
A 1H and 13C NMR study of 4,8,9,10‐tetraaryl‐1,3‐diazatricyclo[3.3.1.13,7]decan‐6‐ones
Authors: Vijayakumar V. , Sundaravadivelu M. , Perumal S. , Lycka A.
Published: August 2002

The 1H and 13C NMR spectra of 4,8,9,10‐tetraaryl‐1,3‐diazatricyclo[3.3.1.13, 7]decan‐6‐ones were measured at 400 and 500 and at 100 and 125 MHz, respectively. The chemical shifts were assigned unambiguously using one‐ and two‐dimensional (H,H‐COSY, C,H‐COSY, NOESY, ROESY and HMBC) NMR spectroscopic data. 1D‐INADEQUATE data also provide an independent assignment of the signals of the carbons of the heterocyclic rings. These results clearly indicate the axial orientation of two aryl groups in one piperidone ring and the equatorial orientation, of the other two aryl groups in another ring. Copyright © 2001 John Wiley & Sons, Ltd.
Structural changes in concentrated solutions of alkali metal monosubstituted benzophenone radical anions as deduced from 1H NMR measurements
Authors: Micha‐Screttas Maria , Heropoulos Georgios A. , Steele Barry R.
Published: August 2002

The radical anions of monosubstituted benzophenones (including 2‐, 3‐ and 4‐methyl‐, 4‐tert‐butyl‐ and 4‐phenylbenzophenone) with lithium, sodium and potassium as countercations in tetrahydrofuran (THF) were studied by paramagnetic solvent 1H NMR shift measurements in the concentration range ca 0.1–1.0 M. In addition to the cation effects, marked positional isomer and substituent effects were found for (1) molar paramagnetism, (2) magnetic state, (3) solubility, (4) structural stability with respect to concentration or addition of cosolvents and (5) rapidity of attainment of their equilibrium structure. The major conclusions which can be drawn are (a) the solvation behavior of the countercation is governed by the anion, (b) an alkyl group in the 4‐position makes the structure of the lithium and sodium monosubstituted benzophenone radical anions concentration dependent and (c) in most cases, alkali metal aromatic ketone radical anions generated by electron transfer from the corresponding naphthalene radical anion attain their equilibrium structure rapidly. The data are interpreted on the basis of the involvement of spin‐triplet interactions within ‘dimers’ or higher clusters. Copyright © 2001 John Wiley & Sons, Ltd.
Enantiomeric differentiation of terpenic olefins by carbon‐13 NMR using chiral binuclear shift reagents
Authors: Baldovini Nicolas , Tomi Félix , Casanova Joseph
Published: August 2002

A study of the enantiomeric differentiation of chiral olefinic terpenes by 13C NMR using binuclear shift reagents is reported. The influence of the [binuclear complex]/[substrate] molar ratio on the chemical shifts and the enantiomeric splittings was investigated with six olefinic substrates. For each compound, a distance‐dependent deshielding effect was observed on all nuclei except on the less substituted sp2 carbon. The enantiomeric differentiation was observed on a large number of carbons of each substrate and was principally attributed to the difference in geometry between the diastereoisomeric complexes. This technique was successfully applied to the enantiomeric differentiation of furanodiene, a sesquiterpene with asymmetry due to its conformational rigidity. Copyright © 2001 John Wiley & Sons, Ltd.
1H and 13C NMR and X‐ray diffraction data for a diosgenyl N,O‐protected glucopyranoside
Authors: Myszka Henryk , Bednarczyk Dorota , Ciunik Zbigniew , Kaca Wiesław
Published: August 2002

The assignments of 1H and 13C NMR chemical shifts together with x‐ray diffraction data for synthesized diosgenyl 3,4,6‐tri‐O‐acetyl‐2‐deoxy‐2‐tetrachlorophthalimido‐β‐D‐glucopyranoside are described. The structure of this glycoside was established by using homo‐ and heteronuclear two‐dimensional NMR techniques. X‐ray diffraction data for this compound are also reported. Copyright © 2002 John Wiley & Sons, Ltd.
2H NMR spin relaxation study of the soft segment motion in alternating ethylene–propylene copolymers
Authors: Nakajima Takeshi , Akiyama Tsutomu , Furuya Hidemine
Published: August 2002

We synthesized three partially deuterated polymer samples, namely a poly(ethylene‐alt‐propylene) (EP) alternating copolymer, a poly(styrene‐b‐EP) diblock copolymer (SEP) and a poly(styrene‐b‐EP‐b‐styrene) triblock copolymer (SEPS). The 2H spin–lattice relaxation time, T1, of EP soft segments above their glass transition temperature was measured by solid‐state 2H NMR spectroscopy. It was found that the block copolymers had a fast and a slow T1 component whereas EP copolymer had only a fast component. The fast T1 components for SEP and SEPS are similar to the T1 value of EP above ca 20°C. The slow T1 component for SEP and SEPS exhibited a minimum at 60°C and approached the value of the fast component near the Tg of polystyrene. The motional behavior of the EP units for SEP is similar to that of SEPS over the entire range of temperature. Copyright © 2001 John Wiley & Sons, Ltd.
Presence of angiotensin‐converting enzyme in follicular fluids of porcine ovaries and its possible involvement in the intrafollicular breakdown of bradykinin
Authors: Matsui Hitoshi , Takahashi Takayuki
Published: August 2002

The follicular fluid of porcine ovaries contains a metalloenzyme capable of hydrolyzing the synthetic substrate, benzyloxycarbonyl‐Val‐Lys‐Met‐MCA. This enzyme was purified by ammonium sulfate fractionation followed by column chromatography on DEAE‐cellulose, CM‐cellulose, Zn2+‐chelating Cellulofine, and Diol‐300 gel‐filtration columns. The molecular weight of the purified enzyme was estimated to be 170,000 by SDS–PAGE and 400,000 by gel‐filtration analysis, suggesting that the native enzyme is a dimer of the 170‐kDa subunit polypeptide. The enzyme activity was drastically enhanced by the presence of chloride ion, and strongly inhibited by captopril and bradykinin potentiator B. A 9‐residue peptide containing a processing site of human amyloid precursor protein was degraded by its dipeptidyl carboxypeptidase activity. Furthermore, the purified protein was recognized by specific antibody raised against human angiotensin‐converting enzyme. The enzyme rapidly degraded bradykinin in vitro. These results indicate that benzyloxycarbonyl‐Val‐Lys‐Met‐MCA‐hydrolyzing enzyme is a porcine angiotensin‐converting enzyme, and that the enzyme may play a role in bradykinin turnover within the follicles of porcine ovaries. Mol. Reprod. Dev. 62: 99‐105, 2002. © 2002 Wiley‐Liss, Inc.
Nuclear ultrastructure in bovine oocytes after inhibition of meiosis by chemical and biological inhibitors
Authors: Faerge I. , Mayes M. , Hyttel P. , Sirard M.A.
Published: August 2002

Various components of the ovarian follicle as well as different chemicals can suppress the resumption of meiosis in cumulus‐oocyte complexes (COCs). In this study the nuclear ultrastructure of bovine COCs was assessed after 8 h of meiotic inhibition with 50 μM roscovitine (ROSC), 50 μM butyrolactone (BL‐I), 2 mM 6‐DMAP, 2 μM cycloheximide (CX), or a theca cell monolayer (TC). COCs were recovered according to standard in vitro methods, cultured in a simple and defined medium, and processed for transmission electron microscopy. Control COCs were processed before onset of culture and multiple oocytes were evaluated for each treatment. In all groups, the oocyte nucleus presented a dense fibrillar nucleolus consisting of a fibrillar sphere with a fibrillar center. In TC and 6‐DMAP inhibited COCs condensed chromatin adhered to the nucleolus while in all other groups the perinuclear chromatin was separated from the nucleolus. In ROSC inhibited COCs, the nuclear envelope presented only slight small amplitude undulation. The BL‐I‐inhibited COCs presented an intermediate level of low amplitude undulation of the NE. In CX, 6‐DMAP, and TC inhibited COCs the nuclear envelope presented extensively low amplitude undulations. In ROSC inhibited COCs, electron‐dense granules formed ring‐shaped structures. In some of the BL‐I inhibited COCs multiple stellate crystal‐like structures were found, and in these COCs the nuclear envelope and the perinuclear cisternae appeared less distinct than in the other BL‐I inhibited COCs. In 6‐DMAP inhibited COCs interchromatin‐like granule clusters were present. In conclusion, the oocyte nuclei in all COCs presented a dense fibrillar nucleolus resembling that in control COCs. However, variations were observed in 1) the nuclear envelope morphology; 2) the chromatin location in relation to the nucleolus; and 3) the presence of different populations of intranuclear granules. Although all treatments inhibited oocyte nucleus breakdown, the mechanisms underlying these effects are different and require further characterization. Mol. Reprod. Dev. 59: 459–467, 2001. © 2001 Wiley‐Liss, Inc.
Effect of blastomere sex and fluorescent labelling on the development of bovine chimeric embryos reconstituted at the four‐cell stage
Authors: Rho Gyu‐Jin , Kang Tae‐Young , Kochhar Harpreet P.S. , Hahnel Ann C. , Betteridge Keith J.
Published: August 2002

The development rate of bovine chimeric embryos reconstituted at the 4‐cell stage is relatively low. If chimerism is to be used as an approach in producing transgenic livestock, it is important to investigate whether this rate is affected by the sex of the blastomeres being combined and if all blastomeres survive equally well. In Experiment 1, blastomeres from 4‐cell stage embryos were inserted into surrogate zonae pellucidae either in pairs to reconstitute 4‐cell chimeras, or as the original sets of four to make handled controls. The development of chimeras with one pair of blastomeres labelled with PKH26‐GL was also investigated. The rate of development into blastocysts was similar in chimeras with unlabelled blastomeres (23%) and in those in which one pair of blastomeres was labelled (26%) and was lower (P < 0.001) than in the handled and IVF control groups (43 and 58%, respectively). Labelled cells were distributed approximately evenly between ICM and trophoblast. In Experiment 2, the effect of sex differences between pairs of blastomeres in chimeras was investigated; chimeras were reconstituted from pairs of blastomeres taken from 4‐cell embryos in which the remaining pair was sexed by PCR. No significant differences according to the sex of constituent blastomeres were detectable (mixed sex, 27%; males, 24%; females, 21%; P > 0.05). These results suggest that, in addition to the negative effects of micromanipulation, factors other than the sex of the blastomeres are involved in the reduced rate of development of chimeric bovine embryos. They also confirm the usefulness of PKH26‐GL labelling for tracking the progeny of cleaving bovine blastomeres at least to the blastocyst stage. Mol. Reprod. Dev. 60: 202–207, 2001. © 2001 Wiley‐Liss, Inc.
Social relationships in the workplace
Authors: Chadsey Janis , Beyer Steve
Published: August 2002

As more workers with disabilities are competitively employed, there are numerous opportunities to form social relationships with their co‐workers. Close social relationships are associated with a number of positive outcomes (e.g., happiness, less stress) and should be actively pursued for those individuals desiring them. In this paper, we describe the types of social interactions displayed in work settings employing workers with and without disabilities. We also discuss some of the social problems experienced by some workers with disabilities. Finally, we describe two general categories of intervention strategies that have been used to impact social relationships: (a) strategies that involve changing the social behaviors of workers with disabilities, and (b) natural support strategies. The results from these strategies are discussed, and future areas of research are described. MRDD Research Reviews 7:128–133, 2001. © 2001 Wiley‐Liss, Inc.
Excitotoxicity in neonatal hypoxia
Authors: Johnston Michael V.
Published: August 2002

Hypoxic‐ischemic encephalopathy (HIE) in neonates is a disorder of excessive neuronal excitation that includes seizures, abnormal EEG activity, and delayed failure of oxidative metabolism with elevated levels of lactic acid in the brain. Evidence from experimental models and clinical investigation indicates that HIE is triggered by a profound disruption in the function of glutamate synapses so that re‐uptake of glutamate from the synapse is impaired and post‐synaptic membranes containing glutamate receptors are depolarized. Severe hypoxemia preferentially depolarizes neuronal membranes, while ischemia probably has greater impact on the activity of glial glutamate re‐uptake. Together, severe hypoxia and ischemia trigger a delayed cascade of events that may result in cell death by necrosis and/or apoptosis. Apoptosis is far more prominent in the neonate than in the adult and activation of cysteine proteases such as caspase‐3 is a very important pathway in excitotoxic neonatal injury. Understanding the complex molecular networks triggered by an excitotoxic insult in the neonate provides insight into patterns of selective neuronal vulnerability and potential therapeutic strategies. MRDD Research Reviews 2001;7:229–234. © 2001 Wiley‐Liss, Inc.
Experimental investigation of RF magnetic field homogeneity in a bridged loop‐gap resonator
Authors: Ono Mitsuhiro , Suenaga Akihiko , Hirata Hiroshi
Published: August 2002

The relationship between an RF magnetic field and an electric shielding plate called a bridge in a bridged loop‐gap resonator (BLGR), which is used for EPR spectroscopy and imaging, is examined. The magnetic field in a BLGR is perturbed due to discontinuity of the conductive loop and electric fringing fields near the gaps. The magnetic field homogeneity in the BLGR can be improved with a bridge. The optimum angle for such bridges can be found by measuring the RF magnetic field. In this study, the RF magnetic field was measured for BLGRs 70 mm in diameter, with a resonance frequency of 302 ± 5 MHz. The field uniformity on a circle with a radius of 27 mm was improved by 8% with bridges at optimal angles. Improved RF magnetic field homogeneity associated with a BLGR is demonstrated. Magn Reson Med 47:415–419, 2002. © 2002 Wiley‐Liss, Inc.
Elimination of Nyquist ghosting caused by read‐out to phase‐encode gradient cross‐terms in EPI
Authors: Grieve Stuart M. , Blamire Andrew M. , Styles Peter
Published: August 2002

Echo‐planar imaging (EPI) commonly suffers from ghosting artifacts caused by zero‐ or first‐order phase differences between the odd and even echoes that constitute an EPI dataset. Small‐bore imaging systems with shielded gradients may suffer significantly from cross‐term eddy currents due to the high degree of manufacturing precision required in such systems compared to larger whole‐body coils. A Nyquist ghost caused by cross‐term eddy current contributions from the read‐out to the phase‐encode axis was identified in a small‐bore system and characterized using a modified EPI experiment and a computer simulation. The artifact was corrected for using both a postprocessing approach and compensation blips along the phase‐encode axis. Correction using compensation blips proved to be a more effective strategy to reduce this artifact than the postprocessing method used. Magn Reson Med 47:337–343, 2002. © 2002 Wiley‐Liss, Inc.
Correction of physiologically induced global off‐resonance effects in dynamic echo‐planar and spiral functional imaging
Authors: Pfeuffer Josef , Van de Moortele Pierre‐Francois , Ugurbil Kamil , Hu Xiaoping , Glover Gary H.
Published: August 2002

In functional magnetic resonance imaging, a rapid method such as echo‐planar (EPI) or spiral is used to collect a dynamic series of images. These techniques are sensitive to changes in resonance frequency which can arise from respiration and are more significant at high magnetic fields. To decrease the noise from respiration‐induced phase and frequency fluctuations, a simple correction of the “dynamic off‐resonance ink‐space” (DORK) was developed. The correction uses phase information from the center ofk‐space and a navigator echo and is illustrated with dynamic scans of single‐shot and segmented EPI and, for the first time, spiral imaging of the human brain at 7 T. Image noise in the respiratory spectrum was measured with an edge operator. The DORK correction significantly reduced respiration‐induced noise (image shift for EPI, blurring for spiral, ghosting for segmented acquisition). While spiral imaging was found to exhibit less noise than EPI before correction, the residual noise after the DORK correction was comparable. The correction is simple to apply and can correct for other sources of frequency drift and fluctuations in dynamic imaging. Magn Reson Med 47:344–353, 2002. © 2002 Wiley‐Liss, Inc.
Imaging spin probe distribution in the tumor of a living mouse with 250 MHz EPR: Correlation with BOLD MRI
Authors: Williams Benjamin B. , al Hallaq Hania , Chandramouli G.V.R. , Barth Eugene D. , Rivers Jonathan N. , Lewis Marta , Galtsev Valeri E. , Karczmar Gregory S. , Halpern Howard J.
Published: August 2002

Electron paramagnetic resonance imaging (EPRI) promises to provide new insights into the physiology of tissues in health and disease. Understanding the in vivo imaging capability of this new modality requires comparison with other physiologically responsive techniques. Here, an initial comparison between 2D EPR spatial imaging of a narrow single line injectable paramagnetic trityl spin probe and 2D slice‐selected carbogen subtraction BOLD MRI is presented. The images were obtained from the same FSa fibrosarcoma grown in the leg of a C3H mouse. This tumor was unusual in comparison with others imaged with subtraction BOLD MRI because of its peripheral distribution of intensity. The spatial distribution of the EPR spin probe showed the same peripheral distribution. The pixel resolutions of these images are comparable. These images provide an early in vivo comparison of EPRI with a well‐established imaging modality. The comparison validates the in vivo distribution of spin probe as imaged with EPRI, and provides a proof of principle for the comparison of BOLD and EPRI. Magn Reson Med 47:634–638, 2002. © 2002 Wiley‐Liss, Inc.
In vivo mapping of the fast and slow diffusion tensors in human brain
Authors: Clark Chris A. , Hedehus Maj , Moseley Michael E.
Published: August 2002

Recent studies have shown that the diffusional signal decay in human brain is non‐monoexponential and may be described in terms of compartmentalized water fractions. Diffusion tensor imaging (DTI), which provides information about tissue structure and orientation, typically uses b values up to 1000 s mm−2 so that the signal is dominated by the fast diffusing fraction. In this study b factors up to 3500 s mm−2 are utilized, allowing the diffusion tensor properties of the more slowly diffusing fraction to be mapped for the first time. The mean diffusivity (MD) of the slow diffusion tensor was found to exhibit strong white/gray matter (WM/GM) contrast. Maps depicting the principal direction of the slow tensor indicated alignment with the fast tensor and the known orientation of the WM pathways. Magn Reson Med 47:623–628, 2002. © 2002 Wiley‐Liss, Inc.
Near infrared muscle spectroscopy in patients with Friedreich's ataxia
Authors: Lynch David R. , Lech Gwen , Farmer Jennifer M. , Balcer Laura J. , Bank William , Chance Britton , Wilson Robert B.
Published: August 2002

Friedreich's ataxia is a progressive neurodegenerative disorder of the afferent cerebellar pathways associated with mitochondrial dysfunction at the cellular level. We have used noninvasive continuous near infrared muscle spectroscopy (NIRS) to investigate the delivery and utilization of oxygen in response to exercise in this disorder. Patients performed an incremental treadmill walking protocol in which levels of muscle deoxygenation or oxygenation were continuously measured in the medial calf muscle. The kinetics of recovery from exercise‐induced deoxygenation, called the half‐time of recovery (t1/2) were determined. The t1/2 was prolonged in patients with Friedreich's ataxia compared with controls, and the degree of prolongation correlated with the length of the shorter GAA repeat, a genetic measure that correlates with the age of onset of disease. The t1/2 also correlated inversely with patient age and with the maximum treadmill speed attained. Several patients also displayed features consistent with inadequate oxygen utilization by muscle. These results suggest that NIRS may be an effective tool for monitoring the biochemical and functional features of Friedreich's ataxia in parallel. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002
Role of adaptive plasticity in recovery of function after damage to motor cortex
Authors: Nudo Randolph J. , Plautz Erik J. , Frost Shawn B.
Published: August 2002

Based upon neurophysiologic, neuroanatomic, and neuroimaging studies conducted over the past two decades, the cerebral cortex can now be viewed as functionally and structurally dynamic. More specifically, the functional topography of the motor cortex (commonly called the motor homunculus or motor map), can be modified by a variety of experimental manipulations, including peripheral or central injury, electrical stimulation, pharmacologic treatment, and behavioral experience. The specific types of behavioral experiences that induce long‐term plasticity in motor maps appear to be limited to those that entail the development of new motor skills. Moreover, recent evidence demonstrates that functional alterations in motor cortex organization are accompanied by changes in dendritic and synaptic structure, as well as alterations in the regulation of cortical neurotransmitter systems. These findings have strong clinical relevance as it has recently been shown that after injury to the motor cortex, as might occur in stroke, post‐injury behavioral experience may play an adaptive role in modifying the functional organization of the remaining, intact cortical tissue. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1000–1019, 2001
A constitutive model for the dynamic and high‐pressure behaviour of a propellant‐like material: Part I: Experimental background and general structure of the model
Authors: Trumel Hervé , Dragon André , Fanget Alain , Lambert Philippe
Published: August 2002

This paper is the first part of a work that aims at developing a mechanical model for the behaviour of propellant‐like materials under high confining pressure and strain rate. The behaviour of a typical material is investigated experimentally. Several microstructural deformation processes are identified and correlated with loading conditions. The resulting behaviour is complex, non‐linear, and characterized by multiple couplings. The general structure of a relevant model is sought using a thermodynamic framework. A viscoelastic‐viscoplastic‐compaction model structure is derived under suitable simplifying assumptions, in the framework of finite, though moderate, strains. Model development, identification and numerical applications are given in the companion paper. Copyright © 2001 John Wiley & Sons, Ltd.
Delayed plastic model for time‐dependent behaviour of materials
Authors: Namikawa Tsutomu
Published: August 2002

A delayed plastic model, based on the theory of plasticity, is proposed to represent the time‐dependent behaviour of materials. It is assumed in this model that the stress can lie outside the yield surface and the conjugate stress called static stress is defined on the yield surface. The stress–strain relation is calculated based on the plastic theory embedding the static stress. Thus, the stress–strain relation of the model practically corresponds to that of the inviscid elastoplastic model under fairly low rate deformation. The delayed plastic model is coupled with the Cam‐clay model for normally consolidated clays. The performance of the model is then examined by comparing the model predictions with reported time‐dependent behaviour of clays under undrained triaxial conditions. It is shown that the model is capable of predicting the effect of strain rate during undrained shear and the undrained creep behaviour including creep rupture. Copyright © 2001 John Wiley & Sons, Ltd.
Frictional contact of laminated elastic half‐spaces allowing interface cavities. Part 1: Analytical treatment
Authors: Kryshtafovych A. A. , Matysiak S. J.
Published: August 2002

The paper deals with the plane problem on frictional contact of stratified elastic half‐spaces provided discontinuity of their direct touch. Imperfectness of contact of the bodies is assumed to be caused by surface unevenness of their surface layers. The problem is formulated within the framework of the homogenized model with microlocal parameters. Using the method of complex potentials in combination with the method of interface gaps the problem is reduced to a singular integral equation on the function of interface gap height. Copyright © 2001 John Wiley & Sons, Ltd.
Alkaline pH changes in the cerebellum of asymptomatic HIV‐infected individuals
Authors: Patton Holly K. , Chu Wen‐Jang , Hetherington Hoby P. , Hollander Jan den , Stewart Katharine E. , Raper James L. , Shelton Brent J. , Benveniste Etty N. , Benos Dale J.
Published: August 2002

Human immunodeficiency virus (HIV) infection of the brain causes a complex cascade of cellular events involving several different cell types that eventually leads to neuronal cell death and the manifestation of the AIDS‐associated dementia complex (ADC). Upon autopsy HIV‐infected individuals show lesions within subcortical regions of the brain, including the cerebellum. Previously we have demonstrated, in primary and cell culture models of rat and human astrocytes, a change in intracellular pH (pHi) due to increased Na+/H+ exchange following exposure to inactivated virus or gp120, the major HIV envelope glycoprotein. To further investigate whether any such in vivo pHi changes occur in human brains subsequent to HIV infection, we measured the pHi of the cerebellum in eight HIV‐positive individuals and nine healthy volunteers using 31P magnetic resonance spectroscopy imaging (MRSI) at high field strength (4.1 T). The results showed a significant difference between the age‐adjusted mean pHi in the cerebellum in control group and patient groups (7.11 ± 0.03 vs 7.16 ± 0.04), and further HIV‐infected individuals displayed a significant increase in the number of cerebellar volume elements that were alkaline. We hypothesize that this propensity towards alterations in cerebellar pHi may portend later neurological involvement resulting from HIV infection. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

ADC

AIDS dementia complex

AIDS

auto‐immune deficiency syndrome

ATP

adenosine triphosphate

CNS

central nervous system

PCr

phosphocreatine

PDE

phosphodiester

Pi

inorganic phosphate

PME

phosphomonoester

ROI

region of interest

SID

spectroscopic imaging display

SNR

signal‐to‐noise ratio

TE

echo time

TIR

inversion recovery time

TR

repetition time.
A two‐phase combined QoS‐based handoff scheme in a wireless ATM network
Authors: Hać Anna , Peng Jing
Published: August 2002

We describe the QoS‐based rerouting algorithm that is designed to implement a two‐phase inter‐switch handoff scheme for wireless ATM networks. We propose to use path extension for each inter‐switch handoff, and invoke path optimization when the handoff path exceeds the delay constraint or maximum path extension hops constraint. We study three types of path optimization schemes: combined QoS‐based, delay‐based and hop based path rerouting schemes. Copyright © 2001 John Wiley & Sons, Ltd.
A framework for the transmission of streaming media to mobile devices
Authors: Curran Kevin , Parr Gerard
Published: August 2002

One interesting problem is the delay imposed upon mobile receivers when switching between wireless cells. We provide a solution to this in the form of an extension of Mobile IP's handoff algorithm. Our solution involves the exploitation of mobility prediction to predict a mobile terminal's future location based on its previous history (i.e. the last cell that it has been in) and for the media stream to be already present and cached by next cells base station ready for receiving by the mobile device. Copyright © 2002 John Wiley & Sons, Ltd.