bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the Numerical and Clinical Accuracy of Four Continuous Glucose Monitors
Authors: Kovatchev Boris , Anderson Stacey , Heinemann Lutz , Clarke William
Published: May 2008

OBJECTIVE—The purpose of this study was to compare the numerical and clinical accuracy of four continuous glucose monitors (CGMs): Guardian, DexCom, Navigator, and Glucoday.

RESEARCH DESIGN AND METHODS—Accuracy data for the four CGMs were collected in two studies: Study 1 enrolled 14 adults with type 1 diabetes at the University of Virginia (UVA), Charlottesville, Virginia; study 2 enrolled 20 adults with type 1 diabetes at the Profil Institute for Metabolic Research, Neuss, Germany. All participants underwent hyperinsulinemic clamps including 1.5–2 h of maintained euglycemia at 5.6 mmol/l followed by descent into hypoglycemia, sustained hypoglycemia at 2.5 mmol/l for 30 min, and recovery. Reference blood glucose sampling was performed every 5 min. The UVA study tested Guardian, DexCom, and Navigator simultaneously; the Profil study tested Glucoday.

RESULTS—Regarding numerical accuracy, during euglycemia, the mean absolute relative differences (MARDs) of Guardian, DexCom, Navigator, and Glucoday were 15.2, 21.2, 15.3, and 15.6%, respectively. During hypoglycemia, the MARDs were 16.1, 21.5, 10.3, and 17.5%, respectively. Regarding clinical accuracy, continuous glucose–error grid analysis (CG-EGA) revealed 98.9, 98.3, 98.6, and 95.5% zones A + B hits in euglycemia. During hypoglycemia, zones A + B hits were 84.4, 97.0, and 96.2% for Guardian, Navigator, and Glucoday, respectively. Because of frequent loss of sensitivity, there were insufficient hypoglycemic DexCom data to perform CG-EGA.

CONCLUSIONS—The numerical accuracy of Guardian, Navigator, and Glucoday was comparable, with an advantage to the Navigator in hypoglycemia; the numerical errors of the DexCom were ∼30% larger. The clinical accuracy of the four sensors was similar in euglycemia and was higher for the Navigator and Glucoday in hypoglycemia.
Long-Term Effects on Medical Costs of Improving Depression Outcomes in Patients With Depression and Diabetes
Authors: Katon Wayne J. , Russo Joan E. , Von Korff Michael , Lin Elizabeth H.B. , Ludman Evette , Ciechanowski Paul S.
Published: May 2008

OBJECTIVE—The purpose of this study was to examine the 5-year effects on total health care costs of the Pathways depression intervention program for patients with diabetes and comorbid depression compared with usual primary care.

RESEARCH DESIGN AND METHODS—The Pathways Study was conducted in nine primary care practices of a large HMO and enrolled 329 patients with diabetes and comorbid major depression. The current study analyzed the differences in long-term medical costs between intervention and usual care patients. Participants were randomly assigned to a nurse depression intervention (n = 164) or to usual primary care (n = 165). The intervention included education about depression, behavioral activation, and a choice of either starting with support of antidepressant medication treatment by the primary care doctor or problem-solving therapy in primary care. Interventions were provided for up to 12 months, and the main outcome measures are health costs over a 5-year period.

RESULTS—Patients in the intervention arm of the study had improved depression outcomes and trends for reduced 5-year mean total medical costs of −$3,907 (95% CI −$15,454 less to $7,640 more) compared with usual care patients. A sensitivity analysis found that these cost differences were largely explained by the patients with depression and the most severe medical comorbidity.

CONCLUSIONS—The Pathways depression collaborative care program improved depression outcomes compared with usual care with no evidence of greater long-term costs and with trends for reduced costs among the more severely medically ill patients with diabetes.
No Apparent Local Effect of Insulin on Microdialysis Continuous Glucose- Monitoring Measurements
Authors: Hermanides Jeroen , Wentholt Iris M. , Hart Augustinus A. , Hoekstra Joost B. , DeVries J. Hans
Published: May 2008

OBJECTIVE—Data investigating the possible disturbing influence of insulin in the vicinity of continuous glucose monitoring (CGM) is lacking. We investigated the hypothesis that high local insulin concentrations would interfere with sensor readings.

RESEARCH DESIGN AND METHODS—Two microdialysis sensors were inserted in the periumbilical region of 10 continuous subcutaneous insulin infusion (CSII)-treated type 1 patients. A test sensor was inserted as close as possible to the insulin catheter and compared with a control sensor. Glucose peak and nadir were induced. Horizontal and vertical shifts were assessed using curve fitting, and mean absolute difference (MAD) between paired blood and sensor values were calculated.

RESULTS—Curve fitting showed no significant differences between the two sensors. MAD ± SD was 8.50 ± 3.47% for the test sensor and 9.21 ± 3.17% for the control sensor, P = 0.72.

CONCLUSIONS—Microdialysis CGM can be accurately performed in the proximity of CSII systems.
Comparision of the effects of subtenon’s and subconjunctival anesthesia on retroorbital hemodynamics
Authors: Cakmak Hasan , Coskun Mehmet , Simavli Huseyin , Gumus Mehmet , Ipek Ali , Simsek Saban
Published: May 2008

The aim of the study was to compare retroorbital blood flow hemodynamics between subconjunctival and sub-Tenon’s anesthesia. This was a prospective, blinded study and included 80 cases. Patients were monitored and treated in the First Ophthalmology Clinic, Ataturk Training and Research Hospital, Turkey. Sub-Tenon’s anesthesia was performed in 42 cases, and subconjunctival anesthesia was performed in 38 cases. Color Doppler imaging to measure ocular blood flow parameters was performed preoperatively and 21 days after cataract operation in each case. Preoperative and postoperative values of resistivity and pulsatility indices in the ophthalmic, central retinal, and short posterior ciliary arteries were compared. Postoperative mean blood flow velocity measurements of ophthalmic artery were not statistically different between the subconjunctival anesthesia group and the sub-Tenon’s anesthesia group (49.63 ± 14.00 vs. 45.85 ± 13.41; P=0.389). Postoperative RI values were higher in the Subtenon’s anesthesia group than in the subconjunctival anesthesia group, but the difference between two groups was not statistically significant (0.81 ± 0.14 vs. 0.74 ± 0.08; P=0.079). The postoperative pulsatility index of the ophthalmic artery, RI of ophthalmic artery, pulsatility index of the central retinal artery, RI of the central retinal artery, and pulsatility index of the posterior ciliary arteries were not significantly different between the subconjunctival and sub-Tenon’s anesthesia groups. In conclusion, the study suggests that postoperative retroorbital blood flow hemodynamics are the same following sub-Tenon’s and subconjunctival anesthesia.
Detection of Simulated Defect Using IR Temperature Sensors and One Point Heating
Authors: Kim Byoung Chul , Heo Young Gun , Suh Yong Kweon , Kim Young Han
Published: May 2008

Infrared temperature sensors, simple device for temperature measurement, have been modified for the measurement of temperature distribution on the metal surface in a way of nondestructive detection of defects of the object. In this study, the IR sensor system is utilized for the defect detection in a cylinder with one point heating, and the performance of the system is examined with an aluminum cylinder having a simulated defect. In addition, a 3-D conduction equation is numerically solved to compare the computed temperature profile with the measured one. The experimental outcome indicates that the defect detection is readily available with the proposed device and the point heating is practical for the applications of the defect detection. It is also found that the measured temperature distribution is comparable to the computed result from the conduction equation.
A Two Dimensional Overlapped Subaperture Polar Format Algorithm Based on Stepped-chirp Signal
Authors: Mao Xinhua , Zhu Daiyin , Nie Xin , Zhu Zhaoda
Published: May 2008

In this work, a 2-D subaperture polar format algorithm (PFA) based on steppedchirp signal is proposed. Instead of traditional pulse synthesis preprocessing, the presented method integrates the pulse synthesis process into the range subaperture processing. Meanwhile, due to the multi-resolution property of subaperture processing, this algorithm is able to compensate the space-variant phase error caused by the radar motion during the period of a pulse cluster. Point target simulation has validated the presented algorithm.
Sensing and 3D Mapping of Soil Compaction
Authors: Tekin Yücel , Kul Basri , Okursoy Rasim
Published: May 2008

Soil compaction is an important physical limiting factor for the root growth and plant emergence and is one of the major causes for reduced crop yield worldwide. The objective of this study was to generate 2D/3D soil compaction maps for different depth layers of the soil. To do so, a soil penetrometer was designed, which was mounted on the three-point hitch of an agricultural tractor, consisting of a mechanical system, data acquisition system (DAS), and 2D/3D imaging and analysis software. The system was successfully tested in field conditions, measuring soil penetration resistances as a function of depth from 0 to 40 cm at 1 cm intervals. The software allows user to either tabulate the measured quantities or generate maps as soon as data collection has been terminated. The system may also incorporate GPS data to create geo-referenced soil maps. The software enables the user to graph penetration resistances at a specified coordinate. Alternately, soil compaction maps could be generated using data collected from multiple coordinates. The data could be automatically stratified to determine soil compaction distribution at different layers of 5, 10,.…, 40 cm depths. It was concluded that the system tested in this study could be used to assess the soil compaction at topsoil and the randomly distributed hardpan formations just below the common tillage depths, enabling visualization of spatial variability through the imaging software.
Measurement of Mechanical Properties of Cantilever Shaped Materials
Authors: Finot Eric , Passian Ali , Thundat Thomas
Published: May 2008

Microcantilevers were first introduced as imaging probes in Atomic Force Microscopy (AFM) due to their extremely high sensitivity in measuring surface forces. The versatility of these probes, however, allows the sensing and measurement of a host of mechanical properties of various materials. Sensor parameters such as resonance frequency, quality factor, amplitude of vibration and bending due to a differential stress can all be simultaneously determined for a cantilever. When measuring the mechanical properties of materials, identifying and discerning the most influential parameters responsible for the observed changes in the cantilever response are important. We will, therefore, discuss the effects of various force fields such as those induced by mass loading, residual stress, internal friction of the material, and other changes in the mechanical properties of the microcantilevers. Methods to measure variations in temperature, pressure, or molecular adsorption of water molecules are also discussed. Often these effects occur simultaneously, increasing the number of parameters that need to be concurrently measured to ensure the reliability of the sensors. We therefore systematically investigate the geometric and environmental effects on cantilever measurements including the chemical nature of the underlying interactions. To address the geometric effects we have considered cantilevers with a rectangular or circular cross section. The chemical nature is addressed by using cantilevers fabricated with metals and/or dielectrics. Selective chemical etching, swelling or changes in Young’s modulus of the surface were investigated by means of polymeric and inorganic coatings. Finally to address the effect of the environment in which the cantilever operates, the Knudsen number was determined to characterize the molecule-cantilever collisions. Also bimaterial cantilevers with high thermal sensitivity were used to discern the effect of temperature variations. When appropriate, we use continuum mechanics, which is justified according to the ratio between the cantilever thickness and the grain size of the materials. We will also address other potential applications such as the ageing process of nuclear materials, building materials, and optical fibers, which can be investigated by monitoring their mechanical changes with time. In summary, by virtue of the dynamic response of a miniaturized cantilever shaped material, we present useful measurements of the associated elastic properties.
Assessment of Unmanned Aerial Vehicles Imagery for Quantitative Monitoring of Wheat Crop in Small Plots
Authors: Lelong Camille C. D. , Burger Philippe , Jubelin Guillaume , Roux Bruno , Labbé Sylvain , Baret Frédéric
Published: May 2008

This paper outlines how light Unmanned Aerial Vehicles (UAV) can be used in remote sensing for precision farming. It focuses on the combination of simple digital photographic cameras with spectral filters, designed to provide multispectral images in the visible and near-infrared domains. In 2005, these instruments were fitted to powered glider and parachute, and flown at six dates staggered over the crop season. We monitored ten varieties of wheat, grown in trial micro-plots in the South-West of France. For each date, we acquired multiple views in four spectral bands corresponding to blue, green, red, and near-infrared. We then performed accurate corrections of image vignetting, geometric distortions, and radiometric bidirectional effects. Afterwards, we derived for each experimental micro-plot several vegetation indexes relevant for vegetation analyses. Finally, we sought relationships between these indexes and field-measured biophysical parameters, both generic and date-specific. Therefore, we established a robust and stable generic relationship between, in one hand, leaf area index and NDVI and, in the other hand, nitrogen uptake and GNDVI. Due to a high amount of noise in the data, it was not possible to obtain a more accurate model for each date independently. A validation protocol showed that we could expect a precision level of 15% in the biophysical parameters estimation while using these relationships.
BIENVENIDOS A LA REVISTA PRODUCTOS NATURALES
Authors: Isaza Martínez José Hipólito
Published: May 2008

Al final de la novena versión del “Congreso Colombiano de Fitoquímica” organizada por el Grupo Polifenoles UTP-CENIVAM en la Universidad Tecnológica de Pereira (Mayo, 2007), surgió la necesidad de una publicación seriada especializada en el área de productos naturales. La gran acogida que tuvo el evento, se manifestó con una asistencia cercana a las 300 personas de casi todo el país, entre investigadores de larga trayectoria y jóvenes de postgrado y pregrado; además de una nutrida participación con más de 150 artículos publicados en un número especial de la “Revista Scientia et Technica (Vol. XIII, No. 33)”. La versión anterior, la octava, realizada en la Universidad de Sucre, en Sincelejo, también fue publicada en la “Revista Actualidades Biológicas (2005, Vol. 27, suplemento 1) con 26 artículos y 43 resúmenes. Las siete versiones anteriores habían tenido, también, una asistencia similar y los trabajos se publicaron en libros de resúmenes.
Effects of Interaural Time and Level Differences on the Binaural Interaction Component of the 80 Hz Auditory Steady-State Response
Authors: Zhang Fawen , Boettcher Flint A.
Published: May 2008

The auditory steady-state evoked response (ASSR) is a scalp-recorded potential elicited by modulated sounds or repetitive transient sounds presented at a high rate. The binaural interaction component (BIC) of the ASSR equals the difference between the response to binaural stimuli and
the sum of the responses to a monaural stimulus presented to the left ear and the right ear. This study examined the effect of the interaural time (ITD) and level (ILD) difference on the BIC of the 80 Hz ASSR. Sixteen human participants with normal hearing were tested. The ITD and ILD were
varied from -1.6 to +1.6 msec and from 0 to +12 dB, respectively. The ITD function of the BIC showed a "V" shape, with a 0 value of BIC at ITD 0 msec and a positive BIC at ITD +0.8 to +1.6 msec. For ILD conditions, the BIC displayed negative values, and its amplitude became more
negative as the ILD was increased. The results indicate that the ITD and ILD may be processed by different groups of binaural neurons in different pathways. It is suggested that the 80 Hz ASSR provides an objective means for evaluating binaural functions in patients such as those with central
auditory processing disorders. Las respuestas evocadas auditivas de estado estable (ASSR) son potenciales de registro en el cráneo generados por sonidos modulados o sonidos repetitivos transitorios presentados a una tasa alta. El componente de interacción biauricular (BIC) de
los ASSR iguala la diferencia entre la respuesta a estímulos bi-auriculares y la suma de respuestas a estímulos mono-auriculares presentados al oído derecho y al oído izquierdo. Este estudio examinó el efecto de la diferencia interauricular de tiempo (ITD)
y de nivel (ILD) a partir del BIC de un ASSR de 80 Hz. Se evaluaron dieciséis participantes humanos con audición normal. Las ITD y ILD se variaron de -1.6 a +1.6 mseg y de 0 a + 12 dB, respectivamente. La función ITD del BIC mostró una forma en "V", con
un valor 0 del BIC con un ITD de 0 mseg y un BIC positivo con un ITD +0.8 a +1.6 mseg. Para condiciones ILD, el BIC mostró valores negativos, y su amplitud se hizo más negativa conforme aumento el ILD. Los resultados indican que el ITD y el ILD pueden ser procesados por grupos
diferentes de neuronas bi-auriculares en diferentes vías. Se sugiere que el ASSR de 80 Hz proporciona un medio objetivo para evaluar las funciones bi-auriculares en pacientes como aquellos con trastornos centrales de procesamiento auditivo.
Relational aggression and victimization in gay male relationships: the role of internalized homophobia
Authors: Kelley Thomas M. , Robertson Richard A.
Published: May 2008

This article presents two studies that are the first to examine relational aggression and relational victimization in gay male peer relationships. A qualitative pilot study provides a strong rationale for a subsequent empirical investigation of 100 young adult, self‐identified gay males. Results of both studies demonstrate that relational aggression and relational victimization are common experiences in gay male relationships. They also reveal forms of relational aggression and victimization that appear to be unique to gay males (e.g., outing). Results of the empirical study found significant relations between engaging in relational aggression against gay males and experiencing relational victimization and between experiencing relational victimization and internalized homophobia. However, there was no significant correlation between internalized homophobia and engaging in relational aggression. A multiple regression analysis found that experiencing relational victimization was correlated more strongly with the combination of engaging in relational aggression and internalized homophobia together than with relational aggression alone. Results are discussed within the framework of Allport's “traits due to victimization” theory and Meyer's theory of “minority stress.” Implications for the prevention of relational aggression/victimization in gay male relationships are offered. Aggr. Behav. 34:475–485, 2008. © 2008 Wiley‐Liss, Inc.
Are the effects of Unreal violent video games pronounced when playing with a virtual reality system?
Authors: Arriaga Patrícia , Esteves Francisco , Carneiro Paula , Monteiro Maria Benedicta
Published: May 2008

This study was conducted to analyze the short‐term effects of violent electronic games, played with or without a virtual reality (VR) device, on the instigation of aggressive behavior. Physiological arousal (heart rate (HR)), priming of aggressive thoughts, and state hostility were also measured to test their possible mediation on the relationship between playing the violent game (VG) and aggression. The participants—148 undergraduate students—were randomly assigned to four treatment conditions: two groups played a violent computer game (Unreal Tournament), and the other two a non‐violent game (Motocross Madness), half with a VR device and the remaining participants on the computer screen. In order to assess the game effects the following instruments were used: a BIOPAC System MP100 to measure HR, an Emotional Stroop task to analyze the priming of aggressive and fear thoughts, a self‐report State Hostility Scale to measure hostility, and a competitive reaction‐time task to assess aggressive behavior. The main results indicated that the violent computer game had effects on state hostility and aggression. Although no significant mediation effect could be detected, regression analyses showed an indirect effect of state hostility between playing a VG and aggression. Aggr. Behav. 34:521–538, 2008. © 2008 Wiley‐Liss, Inc.
The tryptophan hydroxylase‐1 A218C polymorphism is associated with diagnosis, but not suicidal behavior, in borderline personality disorder
Authors: Wilson Scott T. , Stanley Barbara , Brent David A. , Oquendo Maria A. , Huang Yung‐yu , Mann J. John
Published: May 2008

While there is some preliminary evidence that the tryptophan hydroxylase I (TPH1) polymorphisms are related to Borderline Personality Disorder (BPD), it is not clear if this association is due to the high rates of suicidal behavior in this patient group. Because of the reported association between TPH1 polymorphisms and suicidal behavior, determining whether TPH1 is related to BPD independent of suicidal behavior is of particular importance. One hundred patients diagnosed with BPD and 101 healthy controls were genotyped for TPH1 intron 7 A218C polymorphism and assessed for impulsiveness and hostility. The BPD patient group had a higher frequency of A allele carriers (AA/AC genotypes) than the control group (χ2 = 6.12, df = 1, P = 0.01), and differed by genotype frequencies (P = 0.03). Suicide attempter status in the patient group was not related to genotype. Logistic regression analysis controlling for age and gender predicted BPD diagnosis from TPH1 allele group (AA/AC vs. CC, P = 0.03), and TPH1 heterozygotes (AC) appeared to have the highest risk for BPD (P = 0.03). In the full sample, participants with the AC genotype had higher impulsiveness and hostility scores. However, TPH1 did not predict these traits in either of the groups independently, suggesting the association may be an artifact of the association between TPH1 and BPD. Results suggest that the A allele of the tryptophan hydroxylase‐1 A218 polymorphism may be associated with BPD, and that it does not appear to be related to suicidal behavior in this population. An aspect of BPD pathology may be due to serotonergic dysfunction. © 2008 Wiley‐Liss, Inc.
Causes of death in the Kasekela chimpanzees of Gombe National Park, Tanzania
Authors: Williams J. M. , Lonsdorf E. V. , Wilson M. L. , Schumacher‐Stankey J. , Goodall J. , Pusey A. E.
Published: May 2008

Understanding the rates and causes of mortality in wild chimpanzee populations has important implications for a variety of fields, including wildlife conservation and human evolution. Because chimpanzees are long‐lived, accurate mortality data requires very long‐term studies. Here, we analyze 47 years of data on the Kasekela community in Gombe National Park. Community size fluctuated between 38 and 60, containing 60 individuals in 2006. From records on 220 chimpanzees and 130 deaths, we found that the most important cause of mortality in the Kasekela community was illness (58% of deaths with known cause), followed by intraspecific aggression (20% of deaths with known cause). Previous studies at other sites also found that illness was the primary cause of mortality and that some epidemic disease could be traced to humans. As at other study sites, most deaths due to illness occurred during epidemics, and the most common category of disease was respiratory. Intraspecific lethal aggression occurred within the community, including the killing of infants by both males and females, and among adult males during the course of dominance‐related aggression. Aggression between communities resulted in the deaths of at least five adult males and two adult females in the Kasekela and Kahama communities. The frequency of intercommunity violence appears to vary considerably among sites and over time. Intercommunity lethal aggression involving the Kasekela community was observed most frequently during two periods. Other less common causes of death included injury, loss of mother, maternal disability, and poaching. Am. J. Primatol. 70:766–777, 2008. © 2008 Wiley‐Liss, Inc.
Water sorption characteristics in moderately hydrophilic polymers, Part 1: Effect of polar groups concentration and temperature in water sorption in aromatic polysulfones
Authors: Gaudichet‐Maurin E. , Thominette F. , Verdu J.
Published: May 2008

The water equilibrium concentration has been determined for three aromatic polysulfones differentiated essentially by the sulfone concentration, in the 0–0.9 activity range, at temperatures of 50, 60, and 70°C, using a dynamic vapor sorption apparatus. In all the cases, Henry's law was obeyed. The corresponding solubility S and heat of dissolution Hs were determined and their relationships with structure were investigated. The fact that S increases nonlinearly with the sulfone concentration and that Hs is also an increasing function of the latter leads one to abandon classical approaches to polymer–water interactions and propose a model in which water is doubly bonded. Then, S depends on the distribution of distances between polar groups, characterized by a function P(r) and Hs depends on both P(r) and the hydrogen bond potential U(r). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of a poly(acrylic acid)‐graft‐methoxy poly(ethylene oxide) comblike copolymer
Authors: Luo Yanling , Ran Qianping , Wu Shishan , Shen Jian
Published: May 2008

A methoxy poly(ethylene oxide) (MPEO) grafted poly(acrylic acid) (PAA) comblike copolymer was synthesized by the direct condensation of MPEO onto the PAA backbone in the presence of dicyclohexyl dimethylcarbodiimide (DCC) and 4‐dimethylaminopyridine (DMAP). Its chemical structure was characterized by Fourier transform infrared and 1H‐NMR spectroscopies. The effects of different catalysts, solvents, reaction temperatures, and reaction times on the grafting degree of the PAA‐g‐MPEO comblike copolymer were investigated. Compared to p‐toluene sulfonic acid, DMAP/DCC as a catalyst markedly increased the grafting degree. The optimum reaction conditions were a tetrahydrofuran/water mixture solvent, a reaction temperature of 50°C, and a reaction time of 168 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Evaluation of headspace‐gas chromatography/mass spectrometry for the analysis of benzene in vitamin C drinks; pitfalls of headspace in benzene detection
Authors: Ju Hyun Kyoung , Park Jeong Hill , Kwon Sung Won
Published: May 2008

Recently, there have been reports regarding the presence of benzene in vitamin C drinks. This is caused by sodium benzoate and ascorbic acid (vitamin C), which can react together to induce benzene formation. While the headspace gas chromatography method is well known for the detection of benzene, there could be pitfalls in the process of benzene extraction. This study was performed to check if benzene could be generated under high‐temperature incubation conditions. As a result, the amount of benzene detected by headspace‐gas chromatography/mass spectrometry (HSGC/MS) was affected by temperature changes. As the temperature of the sample vial was increased, newly generated benzene from the headspace also increased, causing false‐positive determination of benzene. Although 80°C is generally accepted for the temperature of headspace sample vials, lower temperatures, such as 40°C, minimize the false‐positive identification of benzene. Considering that this minimization allows benzene to be quantified at around 5 ppb, this lower temperature should definitely be considered since benzene, which is formed in sodium benzoate, can appear in vitamin C drinks under certain circumstances. The proposed analysis method of benzene in vitamin C drinks by HSGC/MS at 40°C is an accurate and universal method for the monitoring of benzene without false‐positive identification. Copyright © 2008 John Wiley & Sons, Ltd.
Glycosaminoglycan in cerebrum, cerebellum and brainstem of young sheep brain with particular reference to compositional and structural variations of chondroitin–dermatan sulfate and hyaluronan
Authors: Kilia Virginia , Skandalis Spyros S. , Theocharis Achilleas D. , Theocharis Dimitrios A. , Karamanos Nikos K. , Papageorgakopoulou Nickoletta
Published: May 2008

Recent advances in the structural biology of chondroitin sulfate chains have suggested important biological functions in the development of the brain. Several studies have demonstrated that the composition of chondroitin sulfate chains changes with aging and normal brain maturation. In this study, we determined the concentration of all glycosaminoglycan types, i.e. chondroitin sulfate, dermatan sulfate, keratan sulfate, heparan sulfate, hyaluronan and chondroitin in cerebrum, cerebellum and brainstem of young sheep brain. In all cases, chondroitin sulfate was the predominant glycosaminoglycan type, comprising about 54–58% of total glycosaminoglycans, with hyaluronan being present also in significant amounts of about 19–28%. Of particular interest was the increased presence of the disulfated disaccharides and dermatan sulfate in cerebellum and brainstem, respectively, as well as the detectable and measurable occurrence of chondroitin in young sheep brain. Among the three brain areas, cerebrum was found to be significantly richer in chondroitin sulfate and hyaluronan, two major extracellular matrix components. These findings imply that the extracellular matrix of the cerebrum is different from those of cerebellum and brainstem, and probably this fact is related to the particular histological and functional characteristics of each anatomic area of the brain. Copyright © 2008 John Wiley & Sons, Ltd.
Optimization, validation and application of a method for the determination of trichloroethylene in rat plasma by headspace solid‐phase microextraction gas chromatography mass spectrometry
Authors: Liu Yongzhen , Muralidhara Srinivasa , Bruckner James V. , Bartlett Michael G.
Published: May 2008

Trichloroethylene (TCE) is a small halogenated compound that has been used extensively as a metal degreaser and a solvent for the past 100 years. As a result of its widespread use, TCE can be found in the groundwater of about one‐third of the hazardous waste sites on the United States Environmental Protection Agency's National Priorities List. Human exposure to TCE in the environmental media is of concern because TCE has been found to be carcinogenic in laboratory animals. This paper describes the development and validation of a HS‐SPME‐GC/MS method for determination of TCE in rat plasma. The effects of different parameters such as sample volume, extraction and desorption conditions, fiber positions and salt addition were investigated and optimized. The method is rapid, simple, sensitive and requires a very small sample volume. The lower limit of quantitation was 0.25 ng/mL and correlation coefficient (r2) values for the linear range of 0.25–100 ng/mL were 0.996 or greater. The precision and accuracy for intra‐day and inter‐day were better than 8.0%. This validated method was successfully applied to study the toxicokinetic behavior of TCE following low levels of oral administration. Copyright © 2008 John Wiley & Sons, Ltd.
Liquid chromatography tandem mass spectrometry method for the quantification of clonidine with LLOQ of 10 pg/mL in human plasma
Authors: Nirogi Ramakrishna , Kandikere Vishwottam , Mudigonda Koteshwara , Komarneni Prashanth
Published: May 2008

A sensitive high‐performance liquid chromatography–positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of clonidine in human plasma. Following liquid–liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse‐phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H]+ ions, m/z 230 to 44 for clonidine and m/z 254 to 44 for the internal standard. The assay exhibited a linear dynamic range of 10–2000 pg/mL for clonidine in human plasma. The lower limit of quantification was 10 pg/mL with a relative standard deviation of less than 6.8%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 2.5 min for each sample made it possible to analyze more than 250 human plasma samples per day. The validated method was successfully used to analyze human plasma samples for application in pharmacokinetic studies. Copyright © 2008 John Wiley & Sons, Ltd.
Liquid chromatographic methods for biotransformation studies of ochratoxin A
Authors: Schaut A. , Saeger S. De , Sergent T. , Schneider Y.‐J. , Larondelle Y. , Pussemier L. , Blank R. , Peteghem C. Van
Published: May 2008

Liquid chromatographic methods were used for the detection of ochratoxin A (OTA) and its metabolites ochratoxin alpha (OTα), 10‐hydroxy OTA (10‐OHOTA), 4R‐hydroxy OTA (4R‐OHOTA) and the ethyl ester of OTA (OTC) in in vitro samples, obtained with Caco‐2 cell culture experiments and in in vivo urine samples from sheep. A high‐performance liquid chromatography method with fluorescence detection (HPLC‐FLD) and a liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method were developed and validated for the detection of OTA and its metabolites OTα, 10‐OHOTA, 4R‐OHOTA and OTC, which was used as internal standard. The LOD/LOQ values for OTα, 4R‐OHOTA and OTA were 0.63/2.11, 0.99/3.31 and 0.84/2.81 µg/L, respectively, for the HPLC‐FLD method and 0.98/3.28, 1.11/3.72 and 0.88/2.96 µg/L, respectively for the LC‐MS/MS method. Within‐day and between‐day precision were both <12% for the HPLC‐FLD method, and <10% for the LC‐MS/MS method. The recovery of OTA and its metabolites ranged between 71 and 111% for the HPLC‐FLD method and between 79 and 110 % for the LC‐MS/MS method. In the first experiment only OTA was added to the Caco‐2 cells while in the second experiment 3‐methylcholanthrene (3MC) was also present in the cell culture systems. Besides OTA, which was recovered in all the samples, an unknown compound was also observed in the second experiment. When 3MC was added, the results showed that the OTA concentration in the basolateral samples was decreased by 50%. The methods were also implemented for the analysis of urine samples of sheep, fed increasing amounts of OTA. With the HPLC‐FLD method it could be concluded that the concentration of OTA and OTα increased according to ingested amounts of OTA, with OTα being the most abundant compound. The results obtained with the LC‐MS/MS method confirmed these results. Copyright © 2008 John Wiley & Sons, Ltd.
Determination of sodium cromoglycate in human plasma by liquid chromatography with tandem mass
Authors: Liu Xiao‐yan , Qu Ting‐ting , Wang Ben‐jie , Wei Chun‐min , Yuan Gui‐yan , Zhang Rui , Guo Rui‐chen
Published: May 2008

A sensitive and selective liquid chromatography–tandem mass spectrometric (LC–MS/MS) method was developed and validated for the determination of sodium cromoglycate (SCG) in human plasma after a nasal dose of 10.4 mg sodium cromoglycate nasal spray, using pravastatin sodium as the internal standard. The method was validated over a linear range of 0.300–20.0 ng/mL. SCG and I.S. were extracted from 1.0 mL of heparinized plasma by C18 solid‐phase extraction cartridges using methanol as eluting solvent. The dried residue was reconstituted with 100 µL of mobile phase, and 10 µL was injected onto the LC–MS/MS system. Chromatographic separation was achieved on a C18 column (250 × 4.6 mm i.d., 5 µm particle size) with a mobile phase of methanol–acetonitrile–water (containing 2 mmol/L ammonium acetate; 42.5:42.5:15, v/v/v) at a flow rate of 0.4 mL/min. The analytes were detected with a triple quad LC‐MS/MS using ESI with positive ionization. Ions monitored in the multiple reaction monitoring mode were m/z 469.0 (precursor ion) to m/z 245.0 (product ion) for SCG and m/z 447.2 (precursor ion) to m/z327.1 (product ion) for pravastatin sodium (internal standard) The average recovery of SCG from human plasma was 94.88% and the lower limit of quantitation was 0.3 ng/mL. Results from a 3‐day validation study demonstrated excellent precision and accuracy across the calibration range of 0.3–20 ng/mL. The method was successfully applied to the pharmacokinetic study of SCG in healthy Chinese volunteers. Copyright © 2008 John Wiley & Sons, Ltd.
Identification of major xanthones and steroidal saponins in rat urine by liquid chromatography–atmospheric pressure chemical ionization mass spectrometry technology following oral administration of Rhizoma Anemarrhenae decoction
Authors: Ma Chunhui , Wang Longxing , Tang Yihong , Fan Mingsong , Xiao Hongbin , Huang Chenggang
Published: May 2008

Rhizoma Anemarrhenae (Zhimu in Chinese), the dried rhizome of Anemarrhena asphodeloides Bge. (Fam. Liliaceae), is a well‐known traditional Chinese medicinal herb and has been used clinically in China for centuries to cure various diseases. However, like other traditional Chinese medicines, the effective constituents of this medicine, especially the assimilation and metabolites in vivo, which are very important to show their effects, have not been systematically studied. In this paper, solid‐phase extraction and liquid chromatography–atmospheric pressure chemical ionization mass spectrometry technologies were used to study the constituents absorbed into rat urine and their metabolites after oral administration of Rhizoma Anemarrhenae decoction. A total of 11 compounds, including two xanthones, three of their metabolites and six steroidal saponins, were identified in rat urine sample. They were neomangiferin (1), glucuronide and monomethyl conjugate of mangiferin (2), mangiferin (3), monomethyl conjugate of mangiferin (4), dimethyl conjugate of mangiferin (5), timosaponin N or timosaponin E1 (6), timosaponin BII (7), timosaponin BIII (8), anemarrhenasaponin I or anemarrhenasaponin II (9), timosaponin AII (10) and timosaponin AIII (11). The results would efficaciously narrow the potentially active compounds range in Rhizoma Anemarrhenae decoction, and pave a helpful way for follow‐up mechanism of action research. Copyright © 2008 John Wiley & Sons, Ltd.
Simultaneous determination of seven bioactive lignans in Herpetospermum caudigerum by RP‐HPLC method
Authors: Cong Long‐bo , Yuan Hai‐long , Wang Qi , Li Xian‐yi , Gong Qian‐feng , Xiao Xiao‐he
Published: May 2008

A reversed‐phase high‐performance liquid chromatographic method with diode array detection was established to simultaneously determine the seven bioactive lignans in Herpetospermum caudigerum, namely ent‐isolariciresinol (1), dehydrodiconiferyl alcohol (2), herpetrione (3), herpetin (4), herpetetrone (5), herpetotriol (6) amd herpetal (7). The HPLC assay was performed on a Restek Pinnacle DB C18 column (250 × 4.6 mm, 5 µm) with gradient elution of acetonitrile and 0.1% phosphoric acid within 65 min. The detection wavelength was 240 nm. The flow‐rate was 1.0 mL/min. All calibration curves showed good linearity (r2 > 0.9998) within test ranges. The method was reproducible with intra‐ and inter‐day variation of less than 1.98%. The method provided good accuracy with recoveries in the range 95.19–102.64% with RSDs less than 1.52%. The method was successfully applied to the quantification of seven constituents in 15 H. caudigerum samples collected from different cities. The results indicated that the developed assay could be considered as a suitable quality control method for H. caudigerum. Copyright © 2008 John Wiley & Sons, Ltd.
Analysis of iridoids from Harpagophytum and eleutherosides from Eleutherococcus senticosus in horse urine
Authors: Colas C. , Popot M.‐A. , Garcia P. , Bonnaire Y. , Bouchonnet S.
Published: May 2008

LC/ESI‐MSn methods have been previously set up to detect the administration of (i) Harpagophytum and (ii) preparations containing a plant capable of anti‐stress properties: Eleutherococcus senticosus. Harpagoside has been found to be the main indicator of Harpagophytum administration in the horse. These methods have been applied to a large number of horse urine samples of various origins. Regarding the detection of Harpagophytum administration, harpagoside, harpagide and 8‐para‐coumaroyl harpagide were detected together in only one sample out of 317. Eleutheroside E was found to be the main indicator of Eleutherococcus senticosus administration. It was detected in post‐administration samples collected from two horses having received a feed supplement containing Eleutherococcus senticosus for several days. Out of the 382 samples tested, eleutheroside E was found in an unexpected large number of urine samples (39%) of various origins and its presence cannot be only due to the sole use of herbal dietary supplements. Copyright © 2008 John Wiley & Sons, Ltd.
Microwave‐assisted micellar extraction coupled with solid‐phase extraction for preconcentration of pharmaceuticals in molluscs prior to determination by HPLC
Authors: Cueva‐Mestanza R. , Torres‐Padrón M. E. , Sosa‐Ferrera Z. , Santana‐Rodríguez J. J.
Published: May 2008

A simple and specific analytical method was developed and tested for the determination of pharmaceuticals in mollusc samples. A combination of microwave‐assisted micellar extraction (MAME) and solid‐phase extraction (SPE) using a non‐ionic surfactant, polyoxyethylene 10 lauryl ether, was examined to extract and determine simultaneously a group of pharmaceuticals such as carbamazepine, clorfibric acid, ketoprofen, naproxen, bezafibrate and ibuprofen by liquid chromatography using UV‐diode array detector. The MAME extraction performance was evaluated by studying various parameters such as the volume and concentration of surfactant and microwave conditions. Finally, an OASIS HLB cartridge was used as an optimum SPE sorbent to clean up the extracts and preconcentrate the selected analytes. The proposed method showed satisfactory linearity and reproducibility (between 3 and 15%), as well as detection limits ranging from 30 to 220 ng/g. Finally, the method was successfully applied to the determination of the target pharmaceuticals in various kinds of mollusc samples. This study has demonstrated that microwave‐assisted micellar extraction with solid‐phase extraction may be used as a viable alternative to conventional methods for the extraction of pharmaceuticals in this type of matrices. Copyright © 2008 John Wiley & Sons, Ltd.
A high‐performance liquid chromatographic method for determination of scopolin in rat plasma: application to pharmacokinetic studies
Authors: Xia Yu‐Feng , Dai Yue , Wang Qiang , Cai Fei
Published: May 2008

An analytical method based on high‐performance liquid chromatographic (HPLC) with ultraviolet (UV) detection was developed for determination of scopolin in rat plasma using aesculin as internal standard (IS). After protein precipitation of plasma sample with methanol, the supernatant was directly injected and analyzed. Chromatographic separation was achieved on a C18 column using methanol and distilled water (22:78, v/v) containing 0.2% (v/v) glacial acetic acid as mobile phase with a column temperature of 30°C. The UV detector was set at 338 nm. The calibration curve was linear over the range of 0.105–13.125 µg/mL with a correlation coefficient of 0.9998. The retention times of aesculin and scopolin were 10.4 and 12.8 min, respectively. The recoveries for plasma samples of 0.105, 4.725 and 13.125 µg/mL were 91.08, 95.30 and 96.10%, respectively. The RSD of intra‐ and inter‐day assay variations was less than 7.35%. The lower limit of detection was 0.03 µg/mL .This HPLC assay is a simple, sensitive and accurate and was successfully applied to the pharmacokinetic study of scopolin in rats. Copyright © 2008 John Wiley & Sons, Ltd.
Ultra‐fast chromatographic micro‐assay for quantification of diphenidol in plasma: application in an oral multi‐dose switchability trial
Authors: Marcelín‐Jiménez Gabriel , Morales‐Martínez Miriam , Ángeles‐Moreno Alionka P. , Mendoza‐Morales Luís
Published: May 2008

Pharmacokinetics of diphenidol (DPN) is limited due to the lack of analytical methodology. Here, a micro‐assay for DPN quantification was developed, by coupling ultra‐performance liquid chromatography with tandem mass spectrometry. The procedure involved plasma precipitation and injection of supernatant into UPLC with an Acquity™ C18 column. Detection was in positive electrospray, following transitions of m/z 310.3 → 292.3 and m/z 275.3 → 230.2 for DPN and chlorphenamine (internal standard), respectively. The method was linear with a range of 4–400 ng/mL, and a 2 min run time. This method was applied in a switchability trial, where both formulations of DPN were bioequivalent. Copyright © 2008 John Wiley & Sons, Ltd.
Evaluation of a Sugarcane Bagasse Acid Hydrolysis Technology
Authors: de Ávila Rodrigues F. , Guirardello R.
Published: May 2008

Conceptual process synthesis (CPS) is an important issue in chemical processing industries. In this paper, the general steps of the life cycle of an acid hydrolysis industrial project are evaluated. Chemical route synthesis, process development (experiments for kinetics and fluid dynamics) and process engineering (definition of basic equipment for economic evaluation) are all investigated. A mathematical model was used to generate the most favorable operating conditions for glucose and furfural production from sugarcane bagasse. The material and energy balances were performed by UNISim™ software. The suspension mass fraction and the thermal energy consumption are key issues to account for the profitable operation of the plant.
New Developments in Simulated Moving Bed Chromatography
Authors: Seidel‐Morgenstern A. , Keßler L. C. , Kaspereit M.
Published: May 2008

Chromatographic separation processes are widely used to isolate and purify value added products. Most frequently, such separation processes are performed exploiting the principles of injecting samples of the feed mixture in a repetitive periodic manner and collecting the target products batchwise. In the early 1960s, an alternative operation principle based on using several columns connected in series and exploiting a continuous countercurrent movement between the mobile and stationary phases initiated significant improvements in performing specific separation processes in the petrochemical and sugar industries. In the last decade, the so‐called simulated moving bed (SMB) chromatography has rapidly entered the pharmaceutical industry. In particular enantioseparations using chiral stationary phases have become a strong driving force to develop more sophisticated concepts of continuous chromatography. Currently, the growing interest in efficient methods for the downstream processing of biomolecules enhances interest in SMB processes. This paper gives a brief overview of the new suggestions and trends.