bluuebunny/crossref_metadata_2025 huggingface dataset:
Brief communication: Evidence bearing on the status of Homo habilis at Olduvai Gorge
Authors: Susman Randall L.
Published: July 2008

Students of the early hominin career have debated the status of Homo habilis since its discovery in 1960. Today discussion centers on which specimens should be included in the species and what constitutes the holotype. Recent reviews of early Homo suggest that the Olduvai Hominid 8 foot may sample Paranthropus while the OH 7 skull bones, mandible, and hand sample H. habilis. Moreover, some suggest that while H. habilis in Middle Bed I at Olduvai is craniodentally Homo‐like, the postcranial skeleton of H. habilis is more like that of Australopithecus. Evidence presented here indicates not only that OH 7 and OH 8 represent H. habilis but also that they come from a single individual. The association of OH 35 with OH 7 and OH 8 is less certain. Morphological, pathological, and taphonomic evidence favors the inclusion of OH 35 in the holotype. However, stratigraphic evidence suggests that OH 35 and OH 8 are not coterminous. With or without OH 35, the holotype of H. habilis ranks as one of the most complete early hominin skeletons and the most complete and functionally informative specimen of early Homo. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Gray matter atrophy in multiple sclerosis: A longitudinal study
Authors: Fisher Elizabeth , Lee Jar‐Chi , Nakamura Kunio , Rudick Richard A.
Published: July 2008

Objective

To determine gray matter (GM) atrophy rates in multiple sclerosis (MS) patients at all stages of disease, and to identify predictors and clinical correlates of GM atrophy.

Methods

MS patients and healthy control subjects were observed over 4 years with standardized magnetic resonance imaging (MRI) and neurological examinations. Whole‐brain, GM, and white matter atrophy rates were calculated. Subjects were categorized by disease status and disability progression to determine the clinical significance of atrophy. MRI predictors of atrophy were determined through multiple regression.

Results

Subjects included 17 healthy control subjects, 7 patients with clinically isolated syndromes, 36 patients with relapsing‐remitting MS (RRMS), and 27 patients with secondary progressive MS (SPMS). Expressed as fold increase from control subjects, GM atrophy rate increased with disease stage, from 3.4‐fold normal in clinically isolated syndromes patients converting to RRMS to 14‐fold normal in SPMS. In contrast, white matter atrophy rates were constant across all MS disease stages at approximately 3‐fold normal. GM atrophy correlated with disability. MRI measures of focal and diffuse tissue damage accounted for 62% of the variance in GM atrophy in RRMS, but there were no significant predictors of GM atrophy in SPMS.

Interpretation

Gray matter tissue damage dominates the pathological process as MS progresses, and underlies neurological disabillity. Imaging correlates of gray matter atrophy indicate that mechanisms differ in RRMS and SPMS. These findings demonstrate the clinical relevance of gray matter atrophy in MS, and underscore the need to understand its causes. Ann Neurol 2008
Motor outcome prediction using diffusion tensor tractography in pontine infarct
Authors: Jang Sung Ho , Bai Daiseg , Son Su Min , Lee Jun , Kim Dae‐Shik , Sakong Joon , Kim Dong Gyu , Yang Dong Seok
Published: July 2008

We investigated whether the integrity of the corticospinal tract classified by diffusion tensor tractography (DTT) can predict the motor outcome in 25 patients with pontine infarct. DTTs were obtained in the early stage of stroke (5–30 days) and were classified into two groups (type A: the integrity of corticospinal tract was preserved around the infarct; type B: corticospinal tract was interrupted). DTT type A patients showed better motor function than the type B patients at 6 months after onset. DTT obtained at the early stage of pontine infarct appears to have predictive value for motor outcome in patients with pontine infarct. Ann Neurol 2008
Neurofibrillary tau pathology modulated by genetic variation of α‐synuclein
Authors: Peuralinna Terhi , Oinas Minna , Polvikoski Tuomo , Paetau Anders , Sulkava Raimo , Niinistö Leena , Kalimo Hannu , Hernandez Dena , Hardy John , Singleton Andrew , Tienari Pentti J. , Myllykangas Liisa
Published: July 2008

We analyzed whether genetic variation of α‐synuclein modulates the extent of neuropathological changes in a population‐based autopsied sample of 272 elderly Finns. None of the 11 markers was associated with the extent of neocortical β‐amyloid pathology. The intron 4 marker rs2572324 was associated with the extent of neurofibrillary pathology (p = 0.0006, permuted p = 0.004; Braak stages IV‐VI vs 0‐II). The same variant also showed a trend for association with neocortical Lewy‐related pathology. These results suggest for the first time that variation of α‐synuclein modulates neurofibrillary tau pathology and support the recent observations of an interaction of α‐synuclein and tau in neurodegeneration. Ann Neurol 2008
Sustained improvement of spinal muscular atrophy mice treated with trichostatin a plus nutrition
Authors: Narver Heather L. , Kong Lingling , Burnett Barrington G. , Choe Dong W. , Bosch‐Marcé Marta , Taye Addis A. , Eckhaus Michael A. , Sumner Charlotte J.
Published: July 2008

Early treatment with the histone deacetylase inhibitor, trichostatin A, plus nutritional support extended median survival of spinal muscular atrophy mice by 170%. Treated mice continued to gain weight, maintained stable motor function, and retained intact neuromuscular junctions long after trichostatin A was discontinued. In many cases, ultimate decline of mice appeared to result from vascular necrosis, raising the possibility that vascular dysfunction is part of the clinical spectrum of severe spinal muscular atrophy. Early spinal muscular atrophy disease detection and treatment initiation combined with aggressive ancillary care may be integral to the optimization of histone deacetylase inhibitor treatment in human patients. Ann Neurol 2008; 64:465–470
Admission international normalized ratio and acute infarct volume in ischemic stroke
Authors: Ay Hakan , Arsava Ethem Murat , Gungor Levent , Greer David , Singhal Aneesh B. , Furie Karen L. , Koroshetz Walter J. , Sorensen A. Gregory
Published: July 2008

Objective

The level of anticoagulation at the time of stroke onset may influence the size, composition, and dissolution rate of the occlusive clot. We explored the relation between admission international normalized ratio (INR) and acute infarct volume in patients with ischemic stroke.

Methods

We studied 93 consecutive patients with preadmission warfarin use who had INR measurement and diffusion‐weighted imaging performed within 24 hours of stroke onset. Ninety‐three etiologic stroke subtype‐matched patients without prior warfarin use served as control patients. Linear regression analysis was used to test for independence of INR as a predictor of infarct volume.

Results

In patients with preadmission warfarin use, admission INR was inversely correlated with lesion volume on diffusion‐weighted imaging (r = −0.38). This relation was retained after adjustment for potential covariates (p = 0.014). INR less than 2.0 was associated with 3.5‐fold (95% confidence interval, 2.9–4.2) greater lesion volume on diffusion‐weighted imaging as compared with INR of 2.0 or more. Patients who were on therapeutic INR (≥2.0) had smaller infarcts compared with patients without preadmission warfarin use (p = 0.001). Admission INR was inversely correlated with acute perfusion defect (r = −0.33), chronic infarct volume (r = −0.42), National Institutes of Health Stroke Scale score at admission (r = −0.27), and modified Rankin score at discharge (r = −0.28).

Interpretation

These results suggest that preadmission warfarin use associated with therapeutic level of anticoagulation can offer a benefit in limiting the extent of ischemic injury in an event of acute stroke. Ann Neurol 2008
Asymmetric Aminocatalysis—Gold Rush in Organic Chemistry
Authors: Melchiorre Paolo , Marigo Mauro , Carlone Armando , Bartoli Giuseppe
Published: July 2008

Catalysis with chiral secondary amines (asymmetric aminocatalysis) has become a well‐established and powerful synthetic tool for the chemo‐ and enantioselective functionalization of carbonyl compounds. In the last eight years alone, this field has grown at such an extraordinary pace that it is now recognized as an independent area of synthetic chemistry, where the goal is the preparation of any chiral molecule in an efficient, rapid, and stereoselective manner. This has been made possible by the impressive level of scientific competition and high quality research generated in this area. This Review describes this “Asymmetric Aminocatalysis Gold Rush” and charts the milestones in its development. As in all areas of science, progress depends on human effort.
Interfacial formation of porous membranes with poly(ethylene glycol) in a microfluidic environment
Authors: Kim Dongshin , Beebe David J.
Published: July 2008

In a microfluidic environment, the liquid–liquid interface, formed by laminar flows of immiscible solutions, can be used to generate thin membranes via interfacial polymerization. Because these thin nylon membranes have a very small pore size or lack porosity entirely, their utilization in some biological applications is greatly limited. We introduce an in situ fabrication method using the interfacial reaction of a two‐phase system to generate a porous nylon membrane. The membranes were characterized with scanning electron microscopy and fluorescent beads. Scanning electron microscopy micrographs verified the asymmetrical structure of the porous membrane, and the membrane pore sizes ranged from 0.1 to 1 μm. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.
Polyoxymethylene/polyurethane/alumina ternary composites: Structure, mechanical, thermal and dielectric properties
Authors: Siengchin S. , Karger‐Kocsis J. , Psarras G. C. , Thomann R.
Published: July 2008

Ternary composites composed of polyoxymethylene (POM), polyurethane (PU), and boehmite alumina were produced by melt blending with and without latex precompounding. Latex precompounding served for the predispersion of the alumina particles. The related masterbatch (MB) was produced by mixing the PU latex with water‐dispersible boehmite alumina. The dispersion of the alumina was studied by transmission and scanning electron microscopy techniques (TEM and SEM, respectively) and discussed. The crystallization of POM was inspected by means of differential scanning calorimetry (DSC) and polarized optical microscopy (DSC and polarized light microscopy, respectively). The mechanical and thermomechanical properties of the composites were determined in uniaxial tensile, dynamic‐mechanical thermal analysis (DMTA), short‐time creep tests (performed at various temperatures), and thermogravimetric analysis (TGA). The melt flow of the composites was characterized in a plate/plate rheometer. In addition, the dielectric response of the nanocomposites was investigated by means of broadband dielectric spectroscopy at an ambient temperature. The composites produced by the MB technique outperformed the direct melt (DM) compounded composites in respect to the thermal and mechanical characteristics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal curing behavior of modified urea‐formaldehyde resin adhesives with two formaldehyde scavengers and their influence on adhesion performance
Authors: Park Byung‐Dae , Kang Eun‐Chang , Park Jong‐Young
Published: July 2008

This study investigated, by differential scanning calorimetry, the thermal curing behavior of urea–formaldehyde (UF) resins modified with two formaldehyde scavengers and its impact on the adhesion performance of particleboard bonded with modified UF resin adhesives. As the concentration of the two scavengers [i.e., urea–formaldehyde prepolymer (UFP) and urea solution (US)] increased, the gel time, peak temperature, and onset temperature of the modified UF resins did not change significantly for UFP‐modified UF resins, but these parameters increased for the US‐modified UF resins. These results indicated that the reactivity of the UF resin modified with UFP was maintained, but it deteriorated for the US‐modified UF resins. The formaldehyde emission of particleboard bonded with the modified UF resin decreased with an increase in the scavenger concentration. UFP was more effective than US in scavenging the formaldehyde emission and in achieving adhesion to the UF resin. The results showed an optimum UFP level of 20% in the UF resin for maintaining a balance between the formaldehyde emission and adhesion of the particleboard, and they indicated that both the thermal curing behavior of scavenger‐modified UF resins and the properties of particleboard bonded with them must be taken into account in the evaluation of a formaldehyde scavenger system. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Self‐directed learning in gross human anatomy: Assessment outcomes and student perceptions
Authors: Smythe Gayle , Hughes Diane
Published: July 2008

Speech pathology students enrolled in a lecture‐based gross human anatomy program completed two out of nine topics in self‐directed mode. Student performance in quizzes was compared for the two modes, and the students completed questionnaires on their perceptions of the self‐directed mode of delivery. Students performed as well in the first self‐directed topic as they did in lecture‐based material, but performance declined significantly on the second self‐directed topic. Correlations showed that students who performed well in lecture‐based topics also performed well on self‐directed topics. The major issues that arose in the student questionnaires were primarily related to the amount of content in the topics and the length of time required for completion. We conclude that there is a strong need for appropriate design of distance education materials to reflect student perceptions of length, content, and time investment, and more importantly that there is a need to ensure extensive communication and support of students studying in distance education/self‐directed modes for the first time. Anat Sci Ed 2008. © 2008 American Association of Anatomists.
Thinking outside the (voice) box: A case study of students' perceptions of the relevance of anatomy to speech pathology
Authors: Weir Kristy A.
Published: July 2008

Speech pathology students readily identify the importance of a sound understanding of anatomical structures central to their intended profession. In contrast, they often do not recognize the relevance of a broader understanding of structure and function. This study aimed to explore students' perceptions of the relevance of anatomy to speech pathology. The effect of two learning activities on students' perceptions was also evaluated. First, a written assignment required students to illustrate the relevance of anatomy to speech pathology by using an example selected from one of the four alternative structures. The second approach was the introduction of brief “scenarios” with directed questions into the practical class. The effects of these activities were assessed via two surveys designed to evaluate students' perceptions of the relevance of anatomy before and during the course experience. A focus group was conducted to clarify and extend discussion of issues arising from the survey data. The results showed that the students perceived some course material as irrelevant to speech pathology. The importance of relevance to the students' “state” motivation was well supported by the data. Although the students believed that the learning activities helped their understanding of the relevance of anatomy, some structures were considered less relevant at the end of the course. It is likely that the perceived amount of content and surface approach to learning may have prevented students from “thinking outside the box” regarding which anatomical structures are relevant to the profession. Anat Sci Ed 2008. © 2008 American Association of Anatomists.
Das neue Bewehrungssystem; Druckglieder mit hochfestem Betonstahl SAS 670/800
Authors: Bachmann Hubert , Benz Martin , Falkner Horst , Gerritzen Dominique , Wlodkowski Hans
Published: July 2008

Momentan entsteht in Frankfurt am Main in unmittelbarer Nähe der alten Oper der Opernturm. Es handelt sich dabei um eine 46‐geschossige anspruchsvolle Hochhauskonstruktion. Bei der Planung des Frankfurter Opernturms, der eine Höhe von 169 m aufweist, war u. a. die Dimensionierung der hochbelasteten Stützen eine besondere Herausforderung. Die Megastützen in der über 5‐Geschosse durchgehenden Lobby des Opernturms sollten aus architektonischen Gründen möglichst kleine Querschnitte aufweisen. Diese Forderung wäre bei Verwendung eines normalen Betonstahls nur durch Einsatz von hochfestem Beton umsetzbar gewesen. Als wesentlich wirtschaftlicher erwies es sich jedoch, diese Stützen unter Einsatz eines normalen Regelbetons (C50/60) mit dem hochfesten Bewehrungsstahl der Fa. Stahlwerk Annahütte (SAS 670/800) auszuführen. Die hochbelasteten Fassadenstützen stellten eine ähnliche Herausforderung dar. So sollten diese aufgrund der Architektur, der technischen Gebäudeausstattung und des Gewinns an Nutzfläche ebenfalls möglichst kleine Querschnitte bei großen Schlankheiten (λ >85) aufweisen. Eine Bewehrung mit normalem Betonstahl wäre hier ebenfalls ohne den kostenaufwändigen Einsatz eines hochfesten Betons nicht möglich gewesen. Aus diesem Grund wurden auch die hoch belasteten Fassadenstützen mit SAS 670 bewehrt.

Nachdem im Teil I dieser Veröffentlichung in Heft 5/2008 über die technischen Grundlagen der Stützen mit S 670 berichtet wurde, soll im hier vorliegenden Teil II über den Entwurf des Opernturms Frankfurt, die Ausführung der hochfesten Stützen sowie über die zu Grunde liegende Zustimmung im Einzelfall berichtet werden.
Extending Zelterman's Approach for Robust Estimation of Population Size to Zero‐truncated Clustered Data
Authors: Navaratna W. C. W. , del Rio Vilas Victor J. , Böhning Dankmar
Published: July 2008

Estimation of population size with missing zero‐class is an important problem that is encountered in epidemiological assessment studies. Fitting a Poisson model to the observed data by the method of maximum likelihood and estimation of the population size based on this fit is an approach that has been widely used for this purpose. In practice, however, the Poisson assumption is seldom satisfied. Zelterman (1988) has proposed a robust estimator for unclustered data that works well in a wide class of distributions applicable for count data. In the work presented here, we extend this estimator to clustered data. The estimator requires fitting a zero‐truncated homogeneous Poisson model by maximum likelihood and thereby using a Horvitz–Thompson estimator of population size. This was found to work well, when the data follow the hypothesized homogeneous Poisson model. However, when the true distribution deviates from the hypothesized model, the population size was found to be underestimated. In the search of a more robust estimator, we focused on three models that use all clusters with exactly one case, those clusters with exactly two cases and those with exactly three cases to estimate the probability of the zero‐class and thereby use data collected on all the clusters in the Horvitz–Thompson estimator of population size. Loss in efficiency associated with gain in robustness was examined based on a simulation study. As a trade‐off between gain in robustness and loss in efficiency, the model that uses data collected on clusters with at most three cases to estimate the probability of the zero‐class was found to be preferred in general. In applications, we recommend obtaining estimates from all three models and making a choice considering the estimates from the three models, robustness and the loss in efficiency. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Performance of Risk Prediction Models
Authors: Gerds Thomas A. , Cai Tianxi , Schumacher Martin
Published: July 2008

For medical decision making and patient information, predictions of future status variables play an important role. Risk prediction models can be derived with many different statistical approaches. To compare them, measures of predictive performance are derived from ROC methodology and from probability forecasting theory. These tools can be applied to assess single markers, multivariable regression models and complex model selection algorithms. This article provides a systematic review of the modern way of assessing risk prediction models. Particular attention is put on proper benchmarks and resampling techniques that are important for the interpretation of measured performance. All methods are illustrated with data from a clinical study in head and neck cancer patients. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spontaneous rupture of the oesophagus
Authors: Griffin S M , Lamb P J , Shenfine J , Richardson D L , Karat D , Hayes N
Published: July 2008

Background

The aim of this study was to evaluate the diagnosis, management and outcome of patients with spontaneous rupture of the oesophagus in a single centre.

Methods

Between October 1993 and May 2007, 51 consecutive patients with spontaneous oesophageal rupture were evaluated with contrast radiology and flexible endoscopy. Patients with limited contamination who fulfilled specific criteria were managed by a non-operative approach, whereas the remainder underwent thoracotomy.

Results

The median time to diagnosis was 24 (range 4–604) h. Initial diagnosis was by contrast swallow in 18 of 24 patients, computed tomography in 15 of 17 and endoscopy in 18 of 18. There were no deaths among 17 patients who were managed non-operatively with targeted drainage, intravenous antimicrobials, nasogastric decompression and enteral nutrition. Of 31 patients who underwent primary thoracotomy and oesophageal repair (over a Τ tube in 29), 11 died in hospital. Three patients could not be resuscitated adequately and did not have surgical intervention.

Conclusion

Spontaneous oesophageal rupture represents a spectrum of disease. Accurate radiological and endoscopic evaluation can identify those suitable for radical non-operative treatment and those who require thoracotomy.
Expanding the concepts in protein structure‐function relationships and enzyme kinetics: Teaching using morpheeins
Authors: Lawrence Sarah H. , Jaffe Eileen K.
Published: July 2008

A morpheein is a homo‐oligomeric protein that can exist as an ensemble of physiologically significant and functionally distinct alternate quaternary assemblies. Morpheeins exist in nature and use conformational equilibria between different tertiary structures to form distinct oligomers as a means of regulating their function. Notably, alternate morpheein forms are not misfolded forms of a protein; they are differently assembled native states that contain alternate subunit conformations. Transitions between alternate morpheein assemblies involve oligomer dissociation, conformational change in the dissociated state, and reassembly to a different oligomer. These transitions occur in response to the protein's environment, for example, effector molecules, and represent a new model of allosteric regulation. The unique features of morpheeins are being revealed through detailed characterization of the prototype enzyme, porphobilinogen synthase, which exists in a dynamic equilibrium of a high activity octamer, a low activity hexamer, and two dimer conformations. Morpheeins are likely far more common than previously appreciated. There are, however, both intellectual and experimental barriers to recognizing proteins as morpheeins. These barriers derive from the way we were taught and continue to teach about protein folding, protein purification, protein structure‐function relationships, and enzyme kinetics. This article explores some of these limitations and encourages incorporation of morpheeins into both introductory and advanced biochemistry classes.
Analysis of urinary aromatic acids by liquid chromatography tandem mass spectrometry
Authors: Crow Brian , Bishop Michael , Paliakov Ekaterina , Norton Dean , George Joe , Bralley J. Alexander
Published: July 2008

The separation and detection of 11 urinary aromatic acids was developed using HPLC‐MS/MS. The method features a simple sample preparation involving a single‐step dilution with internal standard and a rapid 8 min chromatographic separation. The accuracy was evaluated by the recovery of known spikes between 87 and 110%. Inter‐ and intra‐assay precision (CV) was below 11% in all cases and the analytes were observed to be stable for up to 8 weeks when stored at −20°C. The method was validated based upon linearity, accuracy, precision and stability and was used to establish reference intervals for children and adults. Copyright © 2008 John Wiley & Sons, Ltd.
Quantitative analysis of the experimental cytotoxic drug cyclopentenyl cytosine and its metabolite in plasma with HPLC tandem mass spectrometry
Authors: Schimmel Kirsten , Lenthe Henk van , Leen Rene , Kulik Willem , Verschuur Arnauld , Guchelaar Henk‐Jan , Kuilenburg André van
Published: July 2008

The cytotoxic drug cyclopentenyl cytosine (CPEC) is currently being investigated in early clinical trials. Monitoring of plasma levels is required for pharmacokinetic analysis and management of toxicity. This paper describes the analysis of CPEC and cyclopentenyl uracil (CPEU) in plasma by HPLC–electrospray ionization tandem mass spectrometry. The calibration curves for CPEC and the metabolite CPEU were linear up to 10 µm with correlation coefficients of 0.997 (SD = 0.002, n = 10) and 0.997 (SD = 0.004, n = 10), respectively. The detection limit for CPEC was 0.03 and 0.12 µm for CPEU. The intra‐ and interassay coefficients of variation for CPEC and CPEU were less then 10%. The usefulness of the method was demonstrated by analyzing CPEC and CPEU in plasma of a patient treated with CPEC. HPLC with electrospray ionization tandem mass spectrometry allowed rapid and sensitive determination of CPEC and CPEU levels in plasma. Copyright © 2008 John Wiley & Sons, Ltd.
Development and validation of HPLC method for imiquimod determination in skin penetration studies
Authors: Paula Daniel De , Martins Carolina Azenha , Bentley Maria Vitória Lopes Badra
Published: July 2008

A simple, rapid and sensitive analytical procedure for the measurement of imiquimod in skin samples after in vitro penetration studies has been developed and validated. In vitro penetration studies were carried out in Franz diffusion cells with porcine skin. Tape stripping technique was used to separate the stratum corneum (SC) from the viable epidermis and dermis. Imiquimod was extracted from skin samples using a 7:3 (v/v) methanol:acetate buffer (100 mm, pH 4.0) solution and ultrasonication. Imiquimod was analyzed by HPLC using C8 column and UV detection at 242 nm. The mobile phase used was acetonitrile:acetate buffer (pH 4.0, 100 mm):diethylamine (30:69.85:0.15, v/v) with flow rate 1 mL/min. Imiquimod eluted at 4.1 min and the running time was limited to 6.0 min. The procedure was linear across the following concentration ranges: 100–2500 ng/mL for both SC and tape‐stripped skin and 20–800 ng/mL for receptor solution. Intra‐day and inter‐day accuracy and precision values were lower than 20% at the limit of quantitation. The recovery values ranged from 80 to 100%. The method is adequate to assay imiquimod from skin samples, enabling the determination of the cutaneous penetration profile of imiquimod by in vitro studies. Copyright © 2008 John Wiley & Sons, Ltd.
Studies on neurosteroids XXIV. Determination of neuroactive androgens, androsterone and 5α‐androstane‐3α,17β‐diol, in rat brain and serum using liquid chromatography–tandem mass spectrometry
Authors: Higashi Tatsuya , Yokoi Hiroyuki , Nagura Yukiko , Nishio Tadashi , Shimada Kazutake
Published: July 2008

The development and validation of liquid chromatography–electrospray ionization–tandem mass spectrometric (LC–ESI‐MS/MS) methods that enable the quantification of neuroactive androgens, androsterone (5α‐androstan‐3α‐ol‐17‐one, 3α,5α‐A) and 5α‐androstane‐3α,17β‐diol (3α,5α‐Adiol), in the rat brain and serum are presented. The androgens were extracted with methanol–acetic acid, purified using solid‐phase extraction cartridges, derivatized with an ESI‐active reagent, isonicotinoyl azide (INA), and then subjected to LC–ESI‐MS/MS. The quantifications were based on selected reaction monitoring mode using the characteristic transitions of the INA derivatives. The methods allowed the reproducible and accurate quantification of the brain and serum neuroactive androgens using a 100 mg or 100 µL sample; the intra‐ and inter‐assay relative standard deviations were below 3.6%, and the percentage accuracy values were 97.1–103.7% for both androgens. The animal study using the methods suggests that most of 3α,5α‐Adiol found in the brain is derived from the periphery, while 3α,5α‐A is not only transported from the periphery into the brain, but also synthesized in the brain by the oxidation of 3α,5α‐Adiol. The androgens in the rats intraperitoneally administered finasteride, a 5α‐reductatse inhibitor, were also measured; this treatment significantly reduced the brain 3α,5α‐A and 3α,5α‐Adiol levels and increased only the brain level of androstenedione, the precursor of 3α,5α‐A. Copyright © 2008 John Wiley & Sons, Ltd.
Automated analysis of fluvoxamine in rat plasma using a column‐switching system and ion‐pair high‐performance liquid chromatography
Authors: Liu Shicheng , Shinkai Norihiro , Kakubari Ikuhiro , Saitoh Hideo , Noguchi Ken‐ichi , Saitoh Takashi , Yamauchi Hitoshi
Published: July 2008

We have established a robust, fully automated analytical method for the analysis of fluvoxamine in rat plasma using a column‐switching ion‐pair high‐performance chromatography system. The plasma sample was injected onto a precolumn packed with Shim‐pack MAYI‐ODS (50 µm), where the drug was automatically purified and enriched by on‐line solid‐phase extraction. After elution of the plasma proteins, the analyte was back‐flushed from the precolumn and then separated isocratically on a reversed‐phase C18 column (L‐column ODS) with a mobile phase (acetonitrile–0.1% phosphoric acid, 36:64, v/v) containing 2 mm sodium 1‐octanesulfonate. The analyte was monitored by a UV detector at a wavelength of 254 nm. The calibration line for fluvoxamine showed good linearity in the range of 5–5000 ng/mL (r > 0.999) with the limit of quantification of 5 ng/mL (RSD = 6.51%). Accuracy ranged from −2.94 to 4.82%, and the within‐ and between‐day precision of the assay was better than 8% across the calibration range. The analytical sensitivity and accuracy of this assay is suitable for characterization of the pharmacokinetics of orally‐administered fluvoxamine in rats. Copyright © 2008 John Wiley & Sons, Ltd.
Improving detection in capillary electrophoresis with laser induced fluorescence via a bubble cell capillary and laser power adjustment
Authors: Rodat Audrey , Gavard Pierre , Couderc François
Published: July 2008

Bubble cells have been frequently employed in capillary electrophoresis (CE) to increase the light path length with UV detection to provide an increase in the observed sensitivity of CE; however this approach has not been commonly used for laser‐induced fluorescence detection (LIF) with CE. In this paper we study the influence of laser power on the sensitivity of detection in using conventional and enlarged fused silica capillaries for CE with LIF. When using the bubble cell capillary, the laser power must be decreased relative to use of the conventional capillary to reduce the effects of photodegradation of the species being illuminated by the laser. Even though the light intensity was decreased, an increase in sensitivity of detection was observed for most compounds when a bubble cell was used. This increase ranged from a factor of 8 for riboflavin (410 nm excitation) to 3.2 for most aromatic compounds (266 nm excitation), when using a 3× bubble cell compared with a conventional capillary. The bubble cell capillary was used for native detection of IgG by LIF at 266 nm. A limit of detection of 60 ng mL−1 was obtained from a 20 pg injection, which was 40 times more sensitive than silver staining in conventional SDS/PAGE. Copyright © 2008 John Wiley & Sons, Ltd.
A human case of an azygos lobe: Determining an anatomical basis for its therapeutic postural drainage
Authors: Arakawa Takamitsu , Terashima Toshio , Miki Akinori
Published: July 2008

An azygos lobe of the human lung is one of the most common lung malformations. However, there are only a few anatomical reports concerning the bronchial and blood supply to this lobe. We encountered the azygos lobe in an anatomical dissection course. The azygos lobe of this case was examined macroscopically and lung parenchyma, including alveoli, terminal bronchioles, and bronchial arteries and veins, was partially removed under a stereoscopic microscope. The azygos lobe was situated medial to the superior lobe and superior to the hilum of the right lung. The parietal pleura wrapped around the azygos vein like a mesentery to form the “meso‐azygos.” Partial removal of the lung parenchyma revealed that the azygos lobe received bronchial branches from the medial components of the apical and anterior branches of the apical segmental bronchus (B1a and B1b), and that these bronchial branches were bent excessively in a medial direction from the parent bronchial trunk. For therapeutic drainage of secretions from a right azygos lobe, a 45° upright sitting posture with the neck flexed to the right side is recommended, because in this posture the bronchial branches to the azygos lobe assume a more vertical orientation to facilitate greater dependent drainage of this lobe. Clin. Anat. 21:524–530, 2008. © 2008 Wiley‐Liss, Inc.
The association of proximal femur geometry with hip fracture risk
Authors: Dinçel V. Ercan , Şengelen Meltem , Sepici Vesile , Çavuşoğlu Turgay , Sepici Behçet
Published: July 2008

We aimed to discuss the risk assessments of patients with hip fractures due to the fall‐related moderate or minimal trauma and compare them with non‐fractured control patients by bone mineral density (BMD) and proximal femur geometric measurements to assess whether geometric measurements of femoral dimensions were associated with femoral strength and hip fracture risk. Forty‐two osteoporotic patients with proximal femur fracture and 40 osteoporotic non‐fractured age and gender‐matched controls were included in the study. Lunar DXA was used for BMD measurements and proximal femur geometric measurements were performed manually on direct X‐rays as hip axial length (HAL), femoral length (FL), and femoral neck width (FW). The trochanteric and total BMD values of the fracture group were significantly lower than the control group. There was a significant increase in FW/FL ratio in the fracture group that would be of specific importance for guidance: if FL values did not increase as did FW, it would point out a risk for fracture. The trochanteric BMD values were correlated with all increased measurements in the control group. There are genetically determined adaptive differences among individuals concerning bone morphology and bone mineral distribution. These different adaptations result in different bone strengths and fracture formation risk. Clin. Anat. 21:575–580, 2008. © 2008 Wiley‐Liss, Inc.
Two unusual anatomic variations create a diagnostic dilemma in distal ulnar nerve compression
Authors: Kiehn Mark W. , Derrick Allison J. , Iskandar Bermans J.
Published: July 2008

Diagnosis of peripheral neuropathies is based upon patterns of functional deficits and electrodiagnostic testing. However, anatomic variations can lead to confounding patterns of physical and electrodiagnostic findings. Authors present a case of ulnar nerve compression due to a rare combination of anatomic variations, aberrant branching pattern, and FCU insertion at the wrist, which posed a diagnostic and therapeutic dilemma. The literature related to isolated distal ulnar motor neuropathy and anatomic variations of the ulnar nerve and adjacent structures is also reviewed. This case demonstrates how anatomic variations can complicate the interpretation of clinical and electrodiagnostic findings and underscores the importance of thorough exploration of the nerve in consideration for possible variations. Clin. Anat. 21:592–597, 2008. © 2008 Wiley‐Liss, Inc.
Adjunctive use of the Rinspiration system for fluidic thrombectomy during primary angioplasty: The Rinspiration international registry
Authors: De Carlo Marco , Wood David A. , Webb John G. , Gerckens Ulrich , Cortese Bernardo , Grube Eberhard , Mancini G.B. John , Krucoff Mitch W. , Rn Colleen McQueen , Goff Tom , Petronio Anna S. , Hamburger Jaap N.
Published: July 2008

Background: Atherothrombotic embolization during primary percutaneous coronary intervention (PCI) induces microvascular obstruction and reduces myocardial tissue reperfusion. A variety of thrombectomy devices have been evaluated as an adjunct to primary PCI in patients with ST‐elevation myocardial infarction (STEMI) to reduce distal embolization. Results have been inconsistent and difficult to predict. The aim of this study was to investigate the safety and efficacy of an innovative thrombectomy device, the Rinspiration System, which simultaneously “rinses” the vessel with turbulent flow and aspirates thrombus. Methods: We prospectively enrolled 109 patients at six academic institutions in three countries referred for primary or rescue PCI for STEMI presenting within 12 hr of symptom onset. The primary endpoint was ≥50% ST‐segment elevation resolution (STR) measured 60 min after PCI by continuous elctrocardiographic recording, Secondary end points included STR > 70% at 60 min, final TIMI flow, myocardial blush score, and 30‐day major adverse cardiac events (MACE). Results: Mean symptom‐to‐PCI time was 4.7 ± 2.7 hr. Rinspiration was successfully delivered in 98% of cases. Final TIMI three flow was achieved in 89% of patients and myocardial blush ≥2 in 78%. Rates of STR ≥ 50% and >70% at 60 min were 97 and 80%, respectively. No device‐related complications were observed. Thirty‐day MACE rate was 4.6%. Conclusions: This international multicenter registry demonstrates that the adjunctive use of Rinspiration during primary PCI is safe and feasible. The excellent STR data compare favorably with results of previous trials using different devices for thrombus management, indicating a potential clinical benefit. © 2008 Wiley‐Liss, Inc.
Microchannels Constructed on Rough Hydrophobic Surfaces
Authors: Watanabe M.
Published: July 2008

A microchannel was constructed between two glass slides, taking advantage of their surface properties. The channel geometry was defined by a line that was previously printed on the slide surface using a highly water‐soluble liquid [2‐(2‐ethoxyethoxy)ethanol] as the ink. Water, which acted as the working fluid flowed along this line. Although the channel did not have any sidewalls, the water was fixed along the printed line due to the large contact‐angle hysteresis of the slide surface whose properties were rough and hydrophobic. Such roughness was more advantageous over smoothness due to the large contact‐angle hysteresis of water and the good wettability of the ink. Using a syringe pump, the water was able to continuously flow through a 1 mm wide and 0.13 mm deep channel without flooding.
A Passive Grooved Micromixer Generating Enhanced Transverse Rotations for Microfluids
Authors: Lin W.
Published: July 2008

A new micromixer geometry is designed to efficiently mix operating microfluids by generating transverse rotation with helical streamlines. The micromixer consists of oblique grooves on the bottom and side of the channel with respect to the long axis of the channel. FLUENT software is used to visualize the mixing effect and to study the mixing efficiency when two completely separated species flow through the microchannel. The mixing effect of the new design is compared to the micromixers discussed in the literature. The simulated result demonstrates that the designed micromixer enhances the mixing effect and effectively removes the specific mixing dead zone in the microchannel.
Microreactor for Synthesis Via Intermediates with Assembled Units Enabling Rapid Operations
Authors: Aoki N. , Kitajima R. , Itoh C. , Mae K.
Published: July 2008

This paper describes a reactor for multistep syntheses via intermediates with improved selectivity of the desired product. This reactor is referred to as an assembled reactor. It consists of mixing, residence time, and heat exchange units. Connection of these units forms a module for a single reaction. Repeated joints of these modules enable the reactor to be used in multistep syntheses. Mixing and the heat transfer rate of the assembled reactor were evaluated. This reactor enabled rapid mixing under the total flow rates of more than 30 mL/min and heat transfer efficiency of the order of 10 K per 10 ms in the heat exchange of fluids with a temperature difference of 20–40 K. This reactor was also applied to the synthesis of bromobenzene via p‐bromophenyllithium and gave a product yield of more than 80 %.
Development of an Industrial Multi‐Injection Microreactor for Fast and Exothermic Reactions – Part II
Authors: Roberge D. M. , Bieler N. , Mathier M. , Eyholzer M. , Zimmermann B. , Barthe P. , Guermeur C. , Lobet O. , Moreno M. , Woehl P.
Published: July 2008

A Grignard reaction performed in a microreactor is presented. The reaction is of type A (highly exothermic and very rapid) and has a low yield which is attributed to a hot spot formed in the mixing zone of the reactor. The reaction yield could be significantly increased by applying the multi‐injection principle, leading to better thermal control in the microreactor. Nevertheless, the microreactor plays a major role in reducing the magnitude of the hot spot. Knowing this, it was possible to design and construct an industrial microreactor with significant advantages such as modularity, high flow rate operation, and low investment expenditure (pumps and flow controller minimization).
Millisecond Methane Steam Reforming Via Process and Catalyst Intensification
Authors: Stefanidis G. D. , Vlachos D. G.
Published: July 2008

The steam reforming of methane on a rhodium/alumina based multifunctional microreactor is simulated using fundamental chemical kinetics in a pseudo‐two‐dimensional microreactor model. The microreactor consists of parallel catalytic plates, whereby catalytic combustion and reforming take place on opposite sides of a wall. Heat exchange happens through the wall. It is shown that reforming can happen in millisecond or lower contact times and proper balancing of flow rates can give high conversions, reasonably high temperatures, and high yield to syngas. It is found that tuning catalyst surface area and internal and external mass and heat transfer through reactor sizing can lead to further process intensification.
Modeling Ignition in Catalytic Microreactors
Authors: Stefanidis G. D. , Kaisare N. S. , Vlachos D. G.
Published: July 2008

A pseudo‐2D reactor model is used to perform a comprehensive study on the catalytic ignition of a lean propane/air mixture in a microreactor with Pt‐coated walls. The results of the in‐house code are verified against the commercial package FLUENT. The roles of inlet velocity, wall conductivity, heat losses or heat transfer to an adjacent endothermic channel, channel gap size, and wall thickness in steady‐state ignition via inlet preheating and resistive heating, are studied. The results show that the heat loss/transfer has the largest effect on ignition for both ignition modes. For an adiabatic reactor, the ignition inlet temperature decreases with increasing wall conductivity. The exact opposite trend is observed at high heat losses. On the other hand, in the resistive heating mode, the external power input at ignition decreases with increasing wall conductivity, irrespective of the heat losses. Lower values of the inlet velocity result in a lower required power input for ignition. The two ignition modes are contrasted, and microreactor and multifunctional devices start‐up strategies are suggested.
Bilinear modelling of batch processes. Part II: a comparison of PLS soft‐sensors
Authors: Camacho José , Picó Jesús , Ferrer Alberto
Published: July 2008

The on‐line monitoring of batch processes based on principal component analysis (PCA) has been widely studied. Nonetheless, researchers have not paid so much attention to the on‐line application of partial least squares (PLS). In this paper, the influence of several issues in the predictive power of a PLS model for the on‐line estimation of key variables in a batch process is studied. Some of the conclusions can help to better understand the capabilities of the proposals presented for on‐line PCA‐based monitoring. Issues like the convenience of batch‐wise or variable‐wise unfolding, the method for the imputation of future measurements and the use of several sub‐models are addressed. This is the first time that the adaptive hierarchical (or multi‐block) approach is extended to the PLS modelling. Also, the formulation of the so‐called trimmed scores regression (TSR), a powerful imputation method defined for PCA, is extended for its application with PLS modelling. Data from two processes, one simulated and one real, are used to illustrate the results. Copyright © 2008 John Wiley & Sons, Ltd.
Einfluss der Werkzeuggeometrie auf die Wärmeübertragung in Conchen
Authors: Schröder J. , Schuchmann H. P. , Braun P. , Lämmli‐Bürgler R.
Published: July 2008

Eine kontrollierte Temperaturführung ist für die Endveredelung der Schokolade entscheidend. Hierfür ist die Verbesserung der Wärmeübertragung im Conchierprozess maßgeblich. In dieser Arbeit werden Strömungssimulationen vorgestellt, die zeigen, dass die Wärmeübertragung durch Staueffekte am Werkzeug mehr begünstigt wird als durch direkten Abtrag. Experimentelle Untersuchungen bestätigten dies.
Neue Verfahren zur Optimierung der Käsereitechnologie
Authors: Hinrichs J.
Published: July 2008

Durch die Einführung neuer Verfahren wurde die Käseherstellung nicht nur wirtschaftlicher gestaltet, sondern es wurden Technologien entwickelt, mit denen die biologische Wertigkeit der Proteine im Käse erhöht und die Textur von Low‐fat‐Produkten deutlich verbessert werden kann. Zahlreiche Technologien und Varianten stehen inzwischen zur Verfügung, um beispielsweise Molkenproteine, die früher mit der Molke für die menschliche Ernährung verloren gingen, in den Prozess zurückzuführen und in die Käsematrix zu integrieren. Die Rückführung von Stoffströmen in einem Prozess kann neue Risiken bedeuten, und diese sind frühzeitig zu berücksichtigen, wie am Beispiel der Phageninaktivierung in zurückgeführten Stoffströmen verdeutlicht wird. Neue Verfahren bedürfen immer einer Adaption an die Technologie der Käsesorte und die gewünschten technofunktionellen Eigenschaften, wobei die Interaktion von Milchinhaltsstoff, Verfahren und Mikrobiologie nicht nur im Prozess, sondern auch während der Reifung zu berücksichtigen ist.
Bewertung und Optimierung von Gefrier‐ und Vakuumtrocknungsverfahren in der Herstellung von mikrobiellen Starterkulturen
Authors: Higl B. , Santivarangkna M. Sc. C. , Först P.
Published: July 2008

Mikrobielle Starterkulturen für die Lebensmittelverarbeitung werden von spezialisierten Herstellern produziert und weltweit vertrieben. Dabei nimmt der Anteil an getrockneten Kulturen immer mehr zu, da diese stabiler und einfacher zu transportieren sind als gefrorene Kulturen. Stand der Technik ist die Gefriertrocknung, die jedoch ein sehr energieintensives Verfahren darstellt. Deshalb wird nach alternativen Trocknungsverfahren wie z. B. der Vakuumtrocknung gesucht und diese erforscht. Um Verfahren vergleichen zu können, muss der Einfluss von Prozessparametern und zugesetzten Schutzstoffen auf die Vitalität der Kultur bekannt sein. Diese Zusammenhänge sind Inhalt des Beitrags, sowohl für die Vakuum‐ als auch für die Gefriertrocknung.