bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of multi‐unit protein hetero‐complexes in the gas phase via ion–ion chemistry
Authors: Gunawardena Harsha P. , McLuckey Scott A. 
Published: June 2004

AbstractThe synthesis of protein hetero‐complex ions via ion–ion reactions in the gas phase is demonstrated in a quadrupole ion trap. Bovine cytochrome c cations and bovine ubiquitin anions are used as reactant species in the stepwise construction of complexes containing as many as six protein sub‐units. For any set of reactants, a series of competitive and consecutive reactions is possible. The yield of complex ions for any given sequence of reactions is primarily limited by the presence of competitive reactions. Proton transfer represents the most important competitive reaction that adversely affects protein complex synthesis. In the present data, proton transfer takes place most extensively in the first step of complex synthesis, when single protein sub‐units are subjected to reaction with one another. Proton transfer is found to be less extensive when one of the reactants is a protein complex. The generation of hexameric hetero‐complexes containing two cytochrome c molecules and four ubiquitin molecules is demonstrated with two different synthesis approaches. The first involved the initial reaction of several charge states of cytochrome c and several charges states of ubiquitin. The sequence of reactions in this example illustrates the array of possible competitive and consecutive reactions associated with even a relatively simple set of multiply charged reactants. The second approach involved the initial reaction of the 9+ charge state of cytochrome c and the 5− charge state of ubiquitin. The latter approach highlights the utility of the multi‐stage mass spectrometric (MSn) capabilities of the ion trap in defining reactant ion identities (i.e. charge states and polarities) so that synthesis reactions can be directed along a particular set of pathways. Copyright © 2004 John Wiley & Sons, Ltd.
Performance in long‐term memory tasks is augmented by a phosphorylated growth factor receptor fragment
Authors: Dash P.K. , Mach S.A. , Moody M.R. , Moore A.N. 
Published: June 2004

AbstractTo elucidate the role of enhanced phosphoinositide‐3‐kinase (PI3‐kinase) activity in memory, a synthetic phosphopeptide (TAT‐YPMDM) containing the p85 regulatory subunit receptor‐binding motif (YXXM) coupled to the cell transduction domain of HIV‐TAT protein was employed. This phosphopeptide bound the p85 subunit of PI3‐kinase, and was internalized by both granule and pyramidal neurons when injected into the hippocampus. Increased lipid kinase activity and enhanced phosphorylation of the PI3‐kinase substrates Akt (protein kinase B) and ribosomal S6 kinase were associated with TAT‐YPMDM administration. Bilateral infusion of the phosphopeptide into the dorsal hippocampus after training improved performance in three hippocampus‐dependent memory tasks: contextual fear conditioning, trace fear conditioning, and the Morris water maze. Both the biochemical and behavioral effects of the TAT‐YPMDM phosphopeptide could be blocked by wortmannin. No effect was observed when a nonphosphorylated peptide (TAT‐YMDM), or a second, unrelated phosphopeptide (TAT‐YPLDL) was utilized. In addition, infusion of the TAT‐YPMDM phosphopeptide did not interfere with memory acquisition or 4 hr memory. In addition, pretesting administration did not affect the ability to recall a previously established long‐term memory. These findings suggest that stimulation of PI3‐kinase activity by phosphorylated receptor fragments containing the YMDM motif augments long‐term memory. © 2004 Wiley‐Liss, Inc.
Effects of sodium caseinate‐ and milk protein concentrate‐based edible coatings on the postharvest quality of Bing cherries
Authors: Certel Muharrem , Uslu Mustafa K , Ozdemir Feramuz 
Published: June 2004

AbstractBing cherries were coated with sodium caseinate‐ or milk protein concentrate‐based edible coatings. Besides the proteins (100 g kg−1), the coating formulations also included glycerol (about 300 g kg−1 protein) and either beeswax or a stearic–palmitic acid blend at a concentration of 0, 100 or 300 g lipid phase kg−1 of protein. All coatings, especially those containing 300 g kg−1 stearic–palmitic acid blend, successfully reduced water loss of the fruits. The edible coatings had a beneficial effect on the sensory quality of the cherries, and there were significant (p < 0.05) effects of the coating treatments on soluble solids, titratable acidity and pH. Copyright © 2004 Society of Chemical Industry
Elevated threshold for intracortical inhibition in focal hand dystonia
Authors: Stinear Cathy M. , Byblow Winston D. 
Published: June 2004

AbstractDifferences between control and focal hand dystonia (FHD) subject groups in short interval intracortical inhibition (SICI) as determined by paired transcranial magnetic stimulation (TMS) can be difficult to demonstrate, due to interindividual differences. The purpose of this study was to compare two TMS methods for assessing SICI in 8 control and 7 FHD subjects. Electromyographic (EMG) data were recorded from the first dorsal interosseous (FDI) muscle of the dominant hands of the control subjects and affected hands of the FHD subjects. The first method used a conventional approach of setting conditioning stimulus intensity to 80% of rest threshold (RTh) and test stimulus intensity to 120% RTh. Three interstimulus intervals (ISIs) were used: 2 msec, 3 msec, and the ISI between 2 and 3 msec that produced optimal SICI. The second method was novel in that test stimulus intensity was set to 150% active threshold (ATh), and conditioning stimulus intensity was varied between 50% and 100% ATh. The latter was determined at the threshold for SICI and expressed as a ratio of ATh. There was no difference between the subject groups in the degree of SICI produced using the first method, at the three ISIs studied. However, using the second method, the SICI threshold:ATh ratio was found to be significantly higher for FHD subjects. This finding suggests that determining the SICI threshold:ATh ratio may be a more sensitive measure of intracortical inhibitory function than more conventional methods. © 2004 Movement Disorder Society
Colonic transit time, sphincter EMG, and rectoanal videomanometry in multiple system atrophy
Authors: Sakakibara Ryuji , Odaka Takeo , Uchiyama Tomoyuki , Liu Rhi , Asahina Masato , Yamaguchi Kazuya , Yamaguchi Taketo , Yamanishi Tomoyuki , Hattori Takamichi 
Published: June 2004

AbstractBoth constipation and fecal incontinence are prominent lower gastrointestinal tract (LGIT) dysfunctions that occur frequently in multiple system atrophy (MSA). We investigated the mechanism of constipation and fecal incontinence in MSA. Colonic transit time (CTT), sphincter electromyography (EMG), and rectoanal videomanometry were performed in 15 patients with MSA (10 men, 5 women; mean age, 63.5 years; mean duration of disease, 3 years; decreased bowel frequency [< 3 times a week] in 9; difficulty in expulsion in 11; fecal incontinence in 3) and 10 age‐matched healthy control subjects (7 men and 3 women; mean age, 62 years; decreased bowel frequency in 2; mild difficulty in expulsion in 2; fecal incontinence in none). Compared to the control subjects, MSA patients had significantly prolonged CTT in the rectosigmoid segment and total colon. Sphincter EMG showed neurogenic motor unit potentials in none of control subjects but in 93% of MSA patients. At the resting state, MSA patients showed a lower anal squeeze pressure (external sphincter weakness) and a smaller increase in abdominal pressure on coughing. During rectal filling, MSA patients showed smaller amplitude in phasic rectal contraction, which was accompanied by an increase in anal pressure that normally decreased, together with leaking in 3 patients. During defecation, most MSA patients could not defecate completely and had larger postdefecation residuals. MSA patients had weak abdominal strain, smaller rectal contraction on defecation, and larger anal contraction on defecation (paradoxical sphincter contraction on defecation), although these differences were not statistically significant. These findings in MSA patients were similar to those in Parkinson's disease patients in our previous study, except for the sphincter denervation and weakness in MSA. Constipation in MSA most probably results from slow colonic transit, decreased phasic rectal contraction, and weak abdominal strain, and fecal incontinence results from weak anal sphincter due to denervation. The responsible sites for these dysfunctions seem to be both central and peripheral nervous systems that regulate the LGIT. © 2004 Movement Disorder Society
Signal‐to‐interference‐plus‐noise ratio estimation for wireless communication systems: Methods and analysis
Authors: Jeske Daniel R. , Sampath Ashwin 
Published: June 2004

AbstractThe Signal‐to‐Interference‐plus‐Noise Ratio (SINR) is an important metric of wireless communication link quality. SINR estimates have several important applications. These include optimizing the transmit power level for a target quality of service, assisting with handoff decisions and dynamically adapting the data rate for wireless Internet applications. Accurate SINR estimation provides for both a more efficient system and a higher user‐perceived quality of service. In this paper, we develop new SINR estimators and compare their mean squared error (MSE) performance. We show that our new estimators dominate estimators that have previously appeared in the literature with respect to MSE. The sequence of transmitted bits in wireless communication systems consists of both pilot bits (which are known both to the transmitter and receiver) and user bits (which are known only by the transmitter). The SINR estimators we consider alternatively depend exclusively on pilot bits, exclusively on user bits, or simultaneously use both pilot and user bits. In addition, we consider estimators that utilize smoothing and feedback mechanisms. Smoothed estimators are motivated by the fact that the interference component of the SINR changes relatively slowly with time, typically with the addition or departure of a user to the system. Feedback estimators are motivated by the fact that receivers typically decode bits correctly with a very high probability, and therefore user bits can be thought of as quasipilot bits. For each estimator discussed, we derive an exact or approximate formula for its MSE. Satterthwaite approximations, noncentral F distributions (singly and doubly) and distribution theory of quadratic forms are the key statistical tools used in developing the MSE formulas. In the case of approximate MSE formulas, we validate their accuracy using simulation techniques. The approximate MSE formulas, of interest in their own right for comparing the quality of the estimators, are also used for optimally combining estimators. In particular, we derive optimal weights for linearly combining an estimator based on pilot bits with an estimator based on user bits. The optimal weights depend on the MSE of the two estimators being combined, and thus the accurate approximate MSE formulas can conveniently be used. The optimal weights also depend on the unknown SINR, and therefore need to be estimated in order to construct a useable combined estimator. The impact on the MSE of the combined estimator due to estimating the weights is examined. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
Revenue management: A real options approach
Authors: Anderson C.K. , Davison M. , Rasmussen H. 
Published: June 2004

AbstractRevenue management is the process of actively managing inventory or capacity to maximize revenues. The active management typically occurs through managerial levers such as price, promotion, or availability. We present a novel real options approach to revenue management that is specifically suited to the car rental business. We illustrate the concept with actual car rental data. The model produces minimally acceptable prices and inventory release quantities (number of cars available for rent at a given price) as a function of remaining time and available inventory. The pricing and inventory release recommendations of the developed model confirm earlier empirical analysis that suggested current practises discount too deeply early in the booking cycle. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
Treatment of CML in pediatric patients: Should imatinib mesylate (STI‐571, Gleevec) or allogeneic hematopoietic cell transplant be front‐line therapy?
Authors: Pulsipher Michael A. 
Published: June 2004

AbstractBackgroundLong‐term survival of pediatric patients with chronic myelogenous leukemia (CML) receiving myeloablative hematopoietic stem cell transplantation from fully‐matched related and unrelated donors has been reported between 60 and 75%, but is associated with significant morbidity. Imatinib mesylate (STI‐571, Gleevec) and reduced intensity conditioning stem cell transplantation (RIC) are two promising new tools that offer potential for decreasing therapy associated morbidity for patients with CML.ResultsLarge trials have shown significant responses in chronic phase patients treated with imatinib and reasonable but short‐lived responses in advanced phase CML. Data from adult studies is beginning to define populations likely to progress or have prolonged responses to imatinib, and some adult treatment paradigms are moving toward reserving transplantation until patients are at risk of failure with imatinib. Early trials of RIC transplantation in CML show decreased transplant related morbidity with efficacy similar to conventional transplantation, but the approach has yet to be verified in phase III studies. Data in pediatric patients with imatinib and RIC transplantation is limited.ConclusionsStudies with imatinib are underway in pediatrics, but whether pediatric dosing schemes will lead to outcomes similar to adults is unknown. Because HLA‐matched myeloablative transplantation offers a high rate of cure in the pediatric population, clinical studies assessing the role of imatinib mesylate and RIC transplantation should be planned carefully in order to avoid sub‐optimal outcomes. © 2004 Wiley‐Liss, Inc.
How do women of diverse backgrounds value prenatal testing outcomes?
Authors: Kuppermann Miriam , Nease Jr Robert F. , Gates Elena , Learman Lee A. , Blumberg Bruce , Gildengorin Virginia , Washington A. Eugene 
Published: June 2004

AbstractObjectivesTo describe women's preferences for prenatal testing outcomes and to explore their association with sociodemographic characteristics and attitudes.MethodsWe conducted a cross‐sectional study of 584 racially/ethnically and socioeconomically diverse pregnant women aged 16 to 47 years recruited from 23 San Francisco Bay Area practices. We assessed preferences for 12 potential prenatal testing outcomes using the time trade‐off metric for all outcomes and the standard gamble metric for two outcomes. Preferences were calculated on a scale of 0 (death) to 1 (perfect health). Participants also completed a sociodemographic and attitude survey.ResultsHighest preference scores were assigned to outcomes resulting in the birth of a chromosomally normal infant (mean = 0.91–0.93; median = 0.99–1.00). Lower scores were obtained for outcomes involving pregnancy loss (mean = 0.69–0.87; median = 0.76–0.92), which were correlated with attitudes regarding miscarriage, pregnancy termination, and Down syndrome. The lowest scores were assigned to Down syndrome–affected births (mean = 0.67–0.69; median = 0.73–0.75), which also were correlated with attitudes toward Down syndrome. We did not find a statistically significant relationship between participants' preference scores and age.ConclusionPreferences for prenatal testing outcomes vary according to the pregnant women's underlying attitudes about pregnancy loss and Down syndrome, and not according to her age. Current age/risk‐based guidelines should account for individual variation in patient preferences. Copyright © 2004 John Wiley & Sons, Ltd.
First‐trimester nuchal translucency and maternal serum free β‐hCG and PAPP‐A can detect triploidy and determine the parental origin
Authors: Yaron Yuval , Ochshorn Yifat , Tsabari Sigal , Shira Anat Bar 
Published: June 2004

AbstractObjectiveTo evaluate the levels of first‐trimester screening markers in triploid pregnancies and to determine the parental origin of triploidy.Study DesignDuring the five‐year study period, 12 322 patients with singleton pregnancies underwent combined first‐trimester screening using nuchal translucency (NT) and maternal serum free β‐human chorionic gonadotrophin (free β‐hCG) and pregnancy associated plasma protein‐A (PAPP‐A) at 10 to 14 weeks' gestation. Maternal serum markers and NT were evaluated in cases of triploidy. Molecular analysis was performed using polymorphic markers to establish the parental source of triploidy.ResultsEight cases of triploidy were detected at a rate of at least 1 in 1540. All cases were electively terminated early in gestation or resulted in spontaneous miscarriage. Two patterns of first‐trimester markers emerged: type I, characterized by extremely high levels of free β‐hCG and elevated NT; and type II, characterized by very low levels of PAPP‐A and free β‐hCG with normal NT. Molecular analysis demonstrated that type I triploidy is of paternal origin (diandric) and type II is of maternal origin (digynic).ConclusionsOn the basis of these results, it may be possible to detect triploid pregnancies in the first trimester and determine their origin using combined first‐trimester screening. Copyright © 2004 John Wiley & Sons, Ltd.
Second‐trimester diagnosis of complete trisomy 9 associated with abnormal maternal serum screen results, open sacral spina bifida and congenital diaphragmatic hernia, and review of the literature
Authors: Chen Chih‐Ping , Chern Schu‐Rern , Cheng Sho‐Jen , Chang Tung‐Yao , Yeh Li‐Fan , Lee Chen‐Chi , Pan Chen‐Wen , Wang Wayseen , Tzen Chin‐Yuan 
Published: June 2004

AbstractObjectivesTo present the prenatal diagnosis of complete trisomy 9 and to review the literatureCaseA 25‐year‐old primigravida woman was referred for amniocentesis at 19 weeks' gestation because of abnormal maternal screen results showing an elevated maternal serum alpha‐fetoprotein (MSAFP) level and a low maternal serum free β‐human chorionic gonadotrophin (MSfreeβ‐hCG) level.ResultsGenetic amniocentesis revealed a karyotype of 47,XX,+9 in the amniocytes and an elevated amniotic fluid AFP level. Ultrasonography demonstrated intrauterine growth restriction, left congenital diaphragmatic hernia, fetal ascites, a sacral spina bifida, a horseshoe kidney, and absence of amniotic fluid. Ultrafast magnetic resonance imaging scans further depicted detailed anatomical configurations of the major congenital malformations. The pregnancy was terminated subsequently. The proband postnatally manifested characteristic facial dysmorphism, limb deformities, and an open sacral spina bifida with myelomeningocele. Cytogenetic analysis of the skin fibroblasts revealed a karyotype of 47,XX,+9. Molecular studies of various uncultured fetal tissues using microsatellite markers confirmed a diagnosis of complete trisomy 9 resulting from a meiotic I nondisjunction error of maternal origin.ConclusionComplete trisomy 9 can be identified prenatally with advanced maternal age, sonographically detected fetal structural abnormalities, and abnormal maternal serum screen results. Fetuses with complete trisomy 9 may be associated with congenital diaphragmatic hernia, an open sacral spina bifida, elevated MSAFP, and low MSfreeβ‐hCG. We suggest detailed prenatal imaging investigations and genetic analyses of multiple fetal tissues when a prenatal diagnosis of trisomy 9 is made. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and characterization of novel optically active poly(amide–imide)s containing N,N′‐(pyromellitoyl)‐bis‐L‐valine diacid chloride and 5,5‐disubstituted hydantoin derivatives under microwave irradiation
Authors: Faghihi Khalil , Zamani Khosrow , Mirsamie Azzizullah , Mallakpour Shadpour 
Published: June 2004

AbstractPyromellitic dianhydride (1,2,4,5‐benzenetetracarboxylic acid 1,2,4,5‐dianhydide) was reacted with L‐valine in a mixture of acetic acid and pyridine (3:2) at room temperature, and then was refluxed at 90–100 °C, N,N′‐(pyromellitoyl)‐bis‐L‐valine diacid was obtained in quantitative yield. The imide–acid was converted to N,N′‐(pyromellitoyl)‐bis‐L‐valine diacid chloride by reaction with thionyl chloride. Rapid and highly efficient synthesis of a number of poly(amide–imide)s was achieved under microwave irradiation using a domestic microwave oven by polycondensation of N,N′‐(pyromellitoyl)‐bis‐L‐valine diacid chloride with six different derivatives of 5,5‐disubstituted hydantoin compounds in the presence of a small amount of a polar organic medium that acts as a primary microwave absorber. A suitable organic medium was o‐cresol. The polycondensation proceeded rapidly, compared with conventional melt polycondensation and solution polycondensation and was almost completed within 8 min, giving a series of poly(amide–imide)s with inherent viscosities in the range 0.15–0.36 dl g−1. The resulting poly(amide–imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by Fourier‐transform infrared (FT‐IR) spectroscopy, elemental analysis, inherent viscosity (ηinh) measurements, solubility testing and specific rotation measurements. The thermal properties of the poly(amide–imide)s were investigated by using thermogravimetric analysis. Copyright © 2004 Society of Chemical Industry
Synthesis and characterization of polyimide/oligomeric methylsilsesquioxane hybrid films
Authors: Lin Wei‐Jung , Chen Wen‐Chang 
Published: June 2004

AbstractIn this study, polyimide/silsesquioxane hybrid materials were synthesized from aminoalkoxysilane‐capped poly(pyromellitic dianhydride‐co‐4,4′‐oxydianiline) (PMDA‐ODA) and oligomeric methylsilsesquioxane (O‐MSSQ) precursors. The O‐MSSQ moiety was used to obtain well characterized nano‐inorganic cage and network structures in the hybrid materials. The effects of molecular structures and composition on the morphologies and properties of the prepared hybrid materials were studied. The phase separation of the prepared hybrid materials could be controlled by varying the molecular weight of the polyimide moiety, the SiOH end group content of the O‐MSSQ or the coupling agent. Homogeneous and transparent hybrid thin films were obtained from the low molecular weight polyimide moiety with a coupling agent, 3‐aminopropyltrimethoxysilane (APrTMS). However, microphase separation occurred if the molecular weight of the polyimide moiety was enhanced or was prepared without a coupling agent, as evidenced by atomic force microscopy (AFM), field emission scanning electron microscopy (FE‐SEM), and electron spectroscopy for chemical analysis (ESCA). The high SiOH content of the O‐MSSQ could enhance the bonding density between the organic and inorganic moiety and thus retard phase separation. The thermal and mechanical properties of the prepared hybrid materials were largely improved compared with the parent polyimide, PMDA‐ODA, and were demonstrated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and thermal‐stress analysis. The hybrid materials showed adjustable refractive index and dielectric constant by varying the O‐MSSQ content. The birefringence of the PMDA‐ODA was reduced by incorporating the O‐MSSQ moiety. This work revealed that the polyimide/O‐MSSQ hybrid materials could have potential applications as optical films or low dielectric constant materials. Copyright © 2004 Society of Chemical Industry