bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of computerized tomography in the evaluation of gastrointestinal bleeding following negative or failed endoscopy
Authors: Stunell H , Buckley O , Lyburn ID , McGann G , Farrell M , Torreggiani WC
Published: February 2009

Gastrointestinal bleeding remains an important cause for emergency hospital admission with a significant related morbidity and mortality. Bleeding may relate to the upper or lower gastrointestinal tracts and clinical history and examination may guide investigations to the more likely source of bleeding. The now widespread availability of endoscopic equipment has made a huge impact on the rapid identification of the bleeding source. However, there remains a large group of patients with negative or failed endoscopy, in whom additional techniques are required to identify the source of bleeding. In the past, catheter angiography and radionuclide red cell labeling techniques were the preferred 'next step' modalities used to aid in identifying a bleeding source within the gastrointestinal tract. However, these techniques are time-consuming and of limited sensitivity and specificity. In addition, catheter angiography is a relatively invasive procedure. In recent years, computerized tomography (CT) has undergone major technological advances in its speed, resolution, multiplanar techniques and angiographic abilities. It has allowed excellent visualization of the both the small and large bowel allowing precise anatomical visualization of many causes of gastrointestinal tract (GIT) bleeding. In addition, recent advances in multiphasic imaging now allow direct visualization of bleeding into the bowel. In many centers CT has therefore become the 'next step' technique in identifying a bleeding source within the GIT following negative or failed endoscopy in the acute setting. In this review article, we review the current literature and discuss the current status of CT as a modality in investigating the patient with GIT bleeding.
Hypereosinophilic syndrome with isolated Loeffler′s endocarditis
Authors: Sen T , Ponde CK , Udwadia ZF
Published: February 2009

Hypereosinophilic syndrome (HES) is classically defined as prolonged, unexplained peripheral eosinophilia in a patient presenting with evidence of end-organ damage. The heart is involved in two forms; endomyocardial fibrosis (Davies disease) and eosinophilic endocarditis (Loffler's endocarditis). It was first reported in 1968 by Hard and Anderson. Chusid and co-workers formulated a definition with strict criteria for the diagnosis of HES as 1) peripheral blood eosinophilia more than 1500 cells/cu mm for at least six months duration 2)signs, symptoms of end-organ (heart, lungs, gastrointestinal tract, skin, bone-marrow, brain) involvement with eosinophil tissue infiltration/injury 3) exclusion of known secondary causes of eosinophilia. We report a case of hypereosinophilic syndrome with Loffler's endocarditis, in the absence of endomyocardial fibrosis. The patient presented with a eosinophilic vegetation over the posterior leaflet of the mitral valve. There was complete resolution of the vegetation after two months of corticosteroid therapy.
Prevention of avascular necrosis in displaced talar neck fractures by hyperbaric oxygenation therapy
Authors: Mei-Dan O , Hetsroni I , Mann G , Melamed Y , Nyska M
Published: February 2009

Talar neck fractures are a rare injury that account for less then 2% of all foot fractures. Displaced fractures are associated with an exceedingly high rate of avascular necrosis (AVN). The incidence of AVN following Hawkins Type 3 fractures of the talar neck may approach 100%, particularly if diagnosis and reduction are delayed. Severe cases may present as pain and disability of the ankle and the subtalar joints due to a talar dome collapse, resulting in degenerative changes that usually require hind foot arthrodesis. We present two cases of traumatic displaced talar neck fractures which were treated surgically more than 2 weeks following injury due to a delay in diagnosis. Both patients underwent hyperbaric oxygen therapy (HBOT) after the operation and neither resulted in AVN of the talus in a three-year follow-up. We suggest that this favorable result may be due to the beneficial effects of HBOT.
Providing a setup and opportunities for better training of postdoctoral research fellows in an academic environment
Authors: Ghayur Muhammad N
Published: February 2009

Thousands of young researchers come from different parts of the world every year to take up postdoctoral (postdoc) research fellowship positions in the developed countries. In the US alone, there were 48,601 postdocs in the year 2005 working in different labs in the fields of science, health and engineering. Many pursue this option for lack of other alternatives. Expectedly, these individuals face a lot of difficulties in making this transition from being a student to becoming an employee of an institution. Many institutions are prepared to make this transition and period of stay easy for their fellows while others are not equipped at all. The presence of a postdoc office (established by an institution) or an association (formed by the fellows) can be of immense help to postdocs. Additionally, the availability of institutional professional development and leadership programs can also help to nurture and polish postdoc fellows into future faculty members and valuable members of the community at large. To name a few, these professional development programs can focus on communication and presentation skills, medical education, teaching and learning, bioethics and mentorship. There is an urgent need to address some or all of these issues so that better training environment and opportunities are available to this group of postdoc fellows.
Tissue microarray
Authors: Avninder S , Ylaya K , Hewitt SM
Published: February 2009

Tissue microarray (TMA) technology is a high-throughput research tool, which has greatly facilitated and accelerated tissue analyses by in-situ technologies. TMAs are amenable to every research method that can be applied on the standard whole sections at enhanced speed. It plays a central role in target verification of results from cDNA arrays, expression profiling of tumors and tissues, and is proving to be a powerful platform for proteomic research. In this review article, primarily meant for students of pathology and oncology, we briefly discuss its basic methodology, applications and merits and limitations.
Comparison of a dipstick enzyme-linked immunosorbent assay with commercial assays for detection of Japanese encephalitis virus-specific IgM antibodies
Authors: Shrivastva A , Tripathi NK , Parida M , Dash PK , Jana AM , Lakshmana Rao PV
Published: February 2009

Background:

Japanese encephalitis (JE) is a major public health concern in Asia including India.

Objectives:

To evaluate an in-house developed dipstick enzyme-linked immunosorbent assay (ELISA) test vis-à-vis two commercial kits for detection of JE virus-specific IgM antibodies.

Setting and Design:

Comparative study carried out in Research and Development centre.

Materials and Methods:

A total of 136 specimens comprising 84 serum and 52 CSF samples were tested by in-house dipstick ELISA, Pan-Bio IgM capture ELISA (Pan-Bio, Australia) and JEV CheX IgM capture ELISA (XCyton, India).

Results:

The overall agreement among all three tests was found to be 92% with both serum and cerebrospinal fluid (CSF) samples. The sensitivity of the dipstick ELISA was found to be 91% with serum and 89% with CSF samples respectively. The specificity of the dipstick ELISA with reference to both commercial assays was found to be 100% in serum and CSF samples in this study.

Conclusions:

The in-house dipstick ELISA with its comparable sensitivity and specificity can be used as a promising test in field conditions since it is simple, rapid and requires no specialized equipment.
The application of C12 biochip in the diagnosis and monitoring of colorectal cancer
Authors: Chen C , Chen LQ , Yang GL , Li Y
Published: February 2009

Background:

The 12 tumor markers' (TMs) biochip diagnostic (C12) system has been proven useful in some previous studies but its value for colorectal cancer (CRC) only was not systematically investigated.

Aims:

To evaluate the value of C12 system for CRC.

Settings and Design:

The associations between TMs and clinicopathological characteristics were evaluated. The most relevant TMs, the most useful combinations, and the correlations between TM levels were assessed.

Materials and Methods:

The TMs detected by the C12 system in the sera of 170 pathologically confirmed CRC patients were analyzed. One or more TMs higher than or equal to reference value were defined as positive.

Statistical Analysis:

Chi-square test, Spearman rank correlation test and Receiver-operating characteristic (ROC) curves were used for the analysis.

Results:

The overall positive rate was 41.76%, and was low in stage 0-I (12.90%). Carcinoembryonic cantigen (CEA) had the highest positive rate of 36.47%. The positive rates were significantly correlated to clinical stages and lymph node status, but not to age, sex, tumor location and pathological types. Any combinations of the five highest positive TMs did not have significantly improvements. The levels of three most related TMs (CEA, CA19-9, CA242) of CRC had positive correlation with each other. CA242 and β-HCG levels were associated with lymph node metastasis.

Conclusions:

C12 system has some value in advanced CRC, but not in early CRC.
Effect of intravenous metoclopramide on intraocular pressure
Authors: Sudheera KS , Bhardwaj N , Yaddanapudi S
Published: February 2009

Background:

Prevention of rise in intraocular pressure (IOP) is essential in patients undergoing surgery for perforated eye injuries. Metoclopramide, a prokinetic agent, is commonly used to hasten gastric emptying in emergency surgeries.

Aim:

To study the change in IOP after intravenous metoclopramide and to study the influence of metoclopramide on change in IOP after succinylcholine and tracheal intubation.

Settings and Design:

A randomized, double-blind, placebo-controlled study of 60 patients undergoing non-ophthalmic elective surgery.

Materials and Methods:

Sixty American Society of Anesthesiologists (ASA) I adult patients were randomly assigned to receive normal saline (Group C) or metoclopramide 10 mg (Group M) 30 min before the induction of anesthesia. Thiopentone was used for induction and succinylcholine for tracheal intubation. Intraocular pressure was measured in both the eyes pre and post drug treatment and succinylcholine and tracheal intubation using Perkins applanation tonometer.

Statistical Analysis:

Student's t-test and repeated measures ANOVA were used. A P value <0.05 was considered as significant.

Results:

Intraocular pressure was consistently lower in Group M than in Group C after the test drug, though the difference was not statistically significant. Intraocular pressure decreased significantly after administration of thiopentone and increased significantly in Groups C and M after tracheal intubation (P < 0.01). Intraocular pressure was comparable between the groups at all the times.

Conclusions:

Metoclopramide does not cause a clinically significant change in IOP nor does it influence the changes in IOP during anesthesia and tracheal intubation. Metoclopramide shows a trend towards decrease in IOP, though clinically insignificant. Therefore metoclopramide can be used to promote gastric emptying in patients with perforated eye injury.
Fungal encephalitis following bone marrow transplantation
Authors: Teive HAG , Carsten ALM , Iwamoto FM , Almeida SM , Munhoz RP , Werneck LC , Medeiros C R , Pasquini R
Published: February 2009

Background:

Central nervous system fungal infections (FI) are important complications and a cause of mortality in patients who receive hematopoietic stem cell transplantation (HSCT).

Aims:

To study the clinical aspects of fungal encephalitis (FE).

Settings and Design:

The study was carried out at the HSCT Center of the Hospital de Clνnicas, Federal University of Paranα, Curitiba, Brazil.

Materials and Methods:

Clinical records and autopsy reports from patients submitted to HSCT with a diagnosis of FE.

Results:

Twelve patients were diagnosed with FE presenting with lowered level of consciousness, hemiparesis and seizures. We were able to identify two subgroups regarding susceptibility to FE: (1) patients with early onset FI and severe leucopoenia, and (2) patients with later onset FI with graft-versus-host disease using immunosuppressive drugs. Eleven of the patients died directly due to the neurological complication, all had post-mortem confirmation of the diagnosis of FI.

Conclusions:

These clinical, paraclinical and temporal patterns may provide the opportunity for earlier diagnosis and interventions.
A trial design that generates only ′′positive′′ results
Authors: Ernst E , Lee MS
Published: February 2009

In this article, we test the hypothesis that randomized clinical trials of acupuncture for pain with certain design features (A + B versus B) are likely to generate false positive results. Based on electronic searches in six databases, 13 studies were found that met our inclusion criteria. They all suggested that acupuncture is effected (one only showing a positive trend, all others had significant results). We conclude that the 'A + B versus B' design is prone to false positive results and discuss the design features that might prevent or exacerbate this problem.
Promotional literature
Authors: Shetty VV , Karve AV
Published: February 2009

There has been a tremendous increase in the number of new and generic drugs coming into the market. The busy practitioner obtains the information from various sources, of which promotional literature forms an important source. The promotional literature provided by the pharmaceutical companies cannot be entirely relied upon; moreover, very few physicians are equipped with the skills of critically appraising it. The new drug should be relevant to the clinician's practice in terms of population studied, the disease and the need for new treatment. The methodology of the study should be carefully judged to determine the authenticity of the evidence. The new drug should be preferred over the existing one if it offers clear advantages in terms of safety, tolerability, efficacy and price. Critical appraisal of promotional literature can provide valuable information to the busy physician to practice evidence-based medicine.
Kayser-Fleischer ring
Authors: Suvarna JC
Published: February 2009

Kayser-Fleischer (K-F) ring seen in Wilson's disease (WD) is due to copper deposition in the Descemet's membrane in the sclero-corneal junction. Although believed to be pathognomic of WD, it may be seen in many other hepatic conditions and intraocular copper-containing foreign bodies. The K-F ring detected in pre-symptomatic cases of WD may lead to speedy diagnosis and early management. Co-relation of K-F ring in WD to the disease severity, disappearance with successful treatment, reappearance with non-compliant treatment may aid in optimum management of WD. The importance of K-F ring detection in first-degree relatives of the index case cannot be over-emphasized.
Right movies on the right seat: Laterality and seat choice
Authors: Okubo Matia
Published: February 2009

Various forms of lateral preferences are found in human behaviour. Conducting two experiments, we investigated the lateral preference for seat choice exhibited by people at the movie theatre. The right‐handed participants (N = 269) tended to choose seats to the right of the screen when they were positively motivated to see the movie. This rightward bias disappeared when they were negatively motivated. In addition, the non‐right‐handed participants (N = 105) did not show any substantial bias in their seat choice. It is well known that visual and emotional information is better processed in the right hemisphere. Considering the visual and emotional nature of movie experiences, the rightward seating bias among right‐handers appears to be determined by their motivation to effectively utilize their right‐hemisphere functions. Copyright © 2009 John Wiley & Sons, Ltd.
First (mediation) step: Stop the shooting
Authors: Mazadoorian Harry N.
Published: February 2009

Violent Chicago streets are as tough a test for mediators as there is. Harry N. Mazadoorian, of Hamden, Conn., draws lessons for commercial ADR from the work of street mediators.
Electrolytic admicellar polymerization of pyrrole on natural rubber/clay nanocomposites
Authors: Pojanavaraphan Tassawuth , Chirasakulkarun Adisorn , Muksing Nattaya , Magaraphan Rathanawan
Published: February 2009

Organic–inorganic composites consisting of natural rubber (NR), polypyrrole (PPy), and sodium montmorillonite (Na‐MMT) were synthesized via electrolytic admicellar polymerization. A constant potential of 9 volts was chosen for the synthesis. The PPy concentration was fixed at 100 mM, and the clay contents were varied from 1 to 7 parts per hundred of rubber (phr). The synthesized nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy (TEM), together with thermal stability (TGA), mechanical properties, and electrical conductivity (σdc) studies. The FTIR spectra indicated the characteristic peaks of both PPy and MMT clay and also evidenced a slight interaction between the PPy chain and the clay layers, verifying the success of electrolytic admicellar polymerization. XRD and TEM results pointed out the good dispersion of clay platelets in the polymer matrix, suggesting an exfoliated structure. The morphology of the nanocomposites was greatly dependent on the amount of MMT clay, especially at a 7 phr loading. The initial modulus and tensile strength of the nanocomposites containing the 7 phr loading were about four and two times higher, compared with unfilled NR/PPy, respectively. Thermal stability studies revealed a slight improvement in the decomposition temperature for the PPy component by the clay layers, whereas the opposite trend was found for the NR component. More interestingly, the electrical conductivity of the admicelled rubber increased significantly (∼ 19–32 times) with increasing clay contents from 1 to 7 phr, in comparison with unfilled NR/PPy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Ultraviolet‐induced aging of flexographic printing plates studied by thermal and structural analysis methods
Authors: Andersson C. , Johnson J. , Järnström L.
Published: February 2009

The properties of photopolymer printing plates subjected to artificial aging processes were investigated with differential scanning calorimetry and microscopic analysis. The results showed that exposure to extended ultraviolet radiation type C in the prepress process caused changes both in the thermal properties and in the structure of the outermost surface layer. Long exposure to ultraviolet radiation type A in a weathering tester led to structural changes at a deeper level and a simultaneous increase in the glass‐transition temperatures of the polymeric material. Spectroscopic analysis showed that extensive oxidation occurred in the outermost surface layer. This study provides insight into important aging processes of the photopolymer printing plates. The knowledge can be used to predict the lifetime of printing plates and to understand the effects of their aging on print quality. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Improvement of poly(vinyl alcohol) properties by the addition of magnesium nitrate
Authors: Kubo Jun‐ichi , Rahman Nelly , Takahashi Nobuaki , Kawai Takahiko , Matsuba Go , Nishida Koji , Kanaya Toshiji , Yamamoto Masahide
Published: February 2009

Aiming at the improvement of mechanical and dielectric properties of poly(vinyl alcohol) (PVA), we prepared composites of PVA and magnesium nitrate hexahydrate. It was found that the composites were very soft and rubber‐like, and the glass transition temperature decreased with increasing the salt concentration. Wide‐angle X‐ray diffraction and small‐angle X‐ray scattering revealed that the crystallites of PVA were destroyed by the additive and it was the cause of the softening. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of acrylic copolymers and crosslinking agents and properties as a film
Authors: Yoo Youngjae , Hong Geun‐Hye , Hur Soon‐Ryoung , Kim Yong Seok , Lee Sung‐Goo , Kim Hyung‐Joong , Lee Jae Heung
Published: February 2009

Copolymers of butyl acrylate (BA)‐methyl methacrylate (MMA)‐acrylic acid (AA) and intraparticle crosslinking agents containing N‐methylol acrylamide (NMA) and ethylene glycol dimethacrylate (EGDMA) were prepared by emulsion copolymerization. After that, films were prepared from the mixture of copolymers and the interparticle crosslinking agents. The interparticle crosslinking agents were prepared from hexamethylene diisocyanate and aziridine ethanol. Mixtures of the copolymer and the interparticle crosslinking agent were cast to films and crosslinked in a convection oven. The effects of the contents of the intra/interparticle crosslinking agents were also evaluated. By increasing the contents of EGDMA, roughness of the films was increased because of the effects of EGDMA acting as an intraparticle crosslinking agent. By increasing the contents of the interparticle crosslinking agent, roughness was also increased by the reaction between the copolymers and interparticle crosslinking agent. Tensile strength and water and chemical resistance of the film were increased, whereas elongation of film was decreased by increasing the contents of interparticle crosslinking agents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and property investigation of three core‐shell fluoroacrylate copolymer latexes
Authors: Junyan Liang , Ling He , Yuansuo Zheng
Published: February 2009

Three core‐shell fluoroacrylate copolymer latices with different fluorinated side chain structure were synthesized in this article by semicontinuous seed emulsion polymerization, using butyl acrylate (BA) and methyl methacrylate (MMA) as acrylate monomer and trifluoroethyl methacrylate (TFEM, C6H7O2F3), hexafluorobutyl methacrylate (HFBM, C8H8O2F6), and dodecafluoroheptyl methacrylate (DFHM, C11H8O2F12) as fluorine‐containing acrylate monomer. The core‐shell fluoroacrylate copolymer latices were named as BA/MMA/TFEM, BA/MMA/HFBM, and BA/MMA/DFHM, respectively. The latex particle morphology and the particle size were determined by transmission electron microscopy and differential scanning calorimetry. The final chemical structure of the latex was analyzed by NMR. The effect of the fluorinated side chain on the core‐shell copolymer latex and film properties, as well as on the superiority of core‐shell copolymer latex to general fluoroacrylate copolymer latex was investigated by energy dispersive X‐ray detector, thermogravimetric analysis, and the determination of contact angle. The analysis results indicated that the particle of fluoroacrylate copolymer latex presented uniform sphere core‐shell structure. Compared with core‐shell BA/MMA/TFEM and BA/MMA/HFBM, BA/MMA/DFHM exhibited not only better surface property as increasing temperature but also better thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal and structural characterization of nanofibers of poly(vinyl alcohol) produced by electrospinning
Authors: Guerrini Lilia M. , de Oliveira Maurício P. , Branciforti Marcia C. , Custódio Tassiana A. , Bretas Rosario E. S.
Published: February 2009

Poly(vinyl alcohol) (PVOH) was obtained from the alkaline hydrolysis of poly(vinyl acetate) (PVAc). Nonwoven membranes (mats) of PVOH nanofibers were produced by electrospinning of solutions of PVOH in water with and without aluminum chloride. The concentration of the PVOH/water solution was 12.4% w/v. The morphology of the mats was analyzed by scanning electron microscopy (SEM). The thermal properties and the degree of crystallinity of the nanofibers were measured by differential scanning calorimetry (DSC); the crystal structure of the mats was evaluated by wide‐angle X‐ray diffraction. The best nanofibers were obtained by electrospinning the PVOH/water solution with aluminum chloride (45% w/v) in which an electrical field of 3.0 kV/cm was applied. It was observed that the addition of the aluminum chloride and the increase in the applied electrical field decreased the number‐average nanofibers diameters. The mats without aluminum chloride had higher melting temperatures and higher degrees of crystallinity than the mats with the salt. The crystal structure of the mats was found to be monoclinic; however, the mats were neither highly oriented nor have a high degree of crystallinity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Embryonic Staging System for the Black Mastiff Bat, Molossus rufus (Molossidae), Correlated With Structure‐Function Relationships in the Adult
Authors: Nolte Mark J. , Hockman Dorit , Cretekos Chris J. , Behringer Richard R. , Rasweiler John J.
Published: February 2009

The helmeted appearance of the black mastiff bat, Molossus rufus, at embryonic stage 21 results from the anterior margins of the ears being progressively situated near the facial midline during development. Comparative bat embryology provides a foundation for understanding unique mammalian and chiropteran (bat) adaptations, such as the marked ability of M. rufus to use its compactly folded wings during terrestrial quadrupedal locomotion. See Nolte et al., on page 155, in this issue.
External concept support for group support systems through Web mining
Authors: Li Jia , Zhang Pengzhu , Cao Jinwei
Published: February 2009

External information plays an important role in group decision‐making processes, yet research about external information support for Group Support Systems (GSS) has been lacking. In this study, we propose an approach to build a concept space to provide external concept support for GSS users. Built on a Web mining algorithm, the approach can mine a concept space from the Web and retrieve related concepts from the concept space based on users' comments in a real‐time manner. We conduct two experiments to evaluate the quality of the proposed approach and the effectiveness of the external concept support provided by this approach. The experiment results indicate that the concept space mined from the Web contained qualified concepts to stimulate divergent thinking. The results also demonstrate that external concept support in GSS greatly enhanced group productivity for idea generation tasks.
Markovian analysis for automatic new topic identification in search engine transaction logs
Authors: Ozmutlu Huseyin C.
Published: February 2009

Topic analysis of search engine user queries is an important task, since successful exploitation of the topic of queries can result in the design of new information retrieval algorithms for more efficient search engines. Identification of topic changes within a user search session is a key issue in analysis of search engine user queries. This study presents an application of Markov chains in the area of search engine research to automatically identify topic changes in a user session by using statistical characteristics of queries, such as time intervals, query reformulation patterns and the continuation/shift status of the previous query. The findings show that Markov chains provide fairly successful results for automatic new topic identification with a high level of estimation for topic continuations and shifts. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of pulsed electromagnetic field on the proliferation and differentiation potential of human bone marrow mesenchymal stem cells
Authors: Sun Li‐Yi , Hsieh Dean‐Kuo , Yu Tzai‐Chiu , Chiu Hsien‐Tai , Lu Sheng‐Fen , Luo Geng‐Hong , Kuo Tom K. , Lee Oscar K. , Chiou Tzyy‐Wen
Published: February 2009

Pulsed electromagnetic fields (PEMFs) have been used clinically to slow down osteoporosis and accelerate the healing of bone fractures for many years. The aim of this study is to investigate the effect of PEMFs on the proliferation and differentiation potential of human bone marrow mesenchymal stem cells (BMMSC). PEMF stimulus was administered to BMMSCs for 8 h per day during culture period. The PEMF applied consisted of 4.5 ms bursts repeating at 15 Hz, and each burst contained 20 pulses. Results showed that about 59% and 40% more viable BMMSC cells were obtained in the PEMF‐exposed cultures at 24 h after plating for the seeding density of 1000 and 3000 cells/cm2, respectively. Although, based on the kinetic analysis, the growth rates of BMMSC during the exponential growth phase were not significantly affected, 20–60% higher cell densities were achieved during the exponentially expanding stage. Many newly divided cells appeared from 12 to 16 h after the PEMF treatment as revealed by the cell cycle analysis. These results suggest that PEMF exposure could enhance the BMMSC cell proliferation during the exponential phase and it possibly resulted from the shortening of the lag phase. In addition, according to the cytochemical and immunofluorescence analysis performed, the PEMF‐exposed BMMSC showed multi‐lineage differentiation potential similar to the control group. Bioelectromagnetics 30:251–260, 2009. © 2009 Wiley‐Liss, Inc.
Collective behavior in cancer cell populations
Authors: Deisboeck Thomas S. , Couzin Iain D.
Published: February 2009

In recent years the argument has been made that malignant tumors represent complex dynamic and self‐organizing biosystems. Furthermore, there is increasing evidence that collective cell migration is common during invasion and metastasis of malignant tumors. Here, we argue that cancer systems may be capable of developing multicellular collective patterns that resemble evolved adaptive behavior known from other biological systems including collective sensing of environmental conditions and collective decision‐making. We present a concept as to how these properties could arise in tumors and why the emergence of such swarm‐like patterns would confer advantageous properties to the spatiotemporal expansion of tumors, and consequently, why understanding and ultimately targeting such collectivity should be of interest for basic and clinical cancer research alike.
Distinguishing heat from light in debate over controversial fossils
Authors: Donoghue Philip C. J. , Purnell Mark A.
Published: February 2009

Fossil organisms offer our only direct insight into how the distinctive body plans of extant organisms were assembled. However, realizing the potential evolutionary significance of fossils can be hampered by controversy over their interpretation. Here, as a guide to evaluating palaeontological debates, we outline the process and pitfalls of fossil interpretation. The physical remains of controversial fossils should be reconstructed before interpreting homologies, and choice of interpretative model should be explicit and justified. Extinct taxa lack characters diagnostic of extant clades because the characters had not yet evolved, because of secondary loss, or because they have rotted away. The latter, if not taken into account, will lead to the spurious assignment of fossils to basally branching clades. Conflicting interpretations of fossils can often be resolved by considering all the steps in the process of anatomical analysis and phylogenetic placement, although we must accept that some fossil organisms are simply too incompletely preserved for their evolutionary significance to be realized.
What are genes “for” or where are traits “from”? What is the question?
Authors: Buchanan Anne V. , Sholtis Samuel , Richtsmeier Joan , Weiss Kenneth M.
Published: February 2009

For at least a century it has been known that multiple factors play a role in the development of complex traits, and yet the notion that there are genes “for” such traits, which traces back to Mendel, is still widespread. In this paper, we illustrate how the Mendelian model has tacitly encouraged the idea that we can explain complexity by reducing it to enumerable genes. By this approach many genes associated with simple as well as complex traits have been identified. But the genetic architecture of biological traits, or how they are made, remains largely unknown. In essence, this reflects the tension between reductionism as the current “modus operandi” of science, and the emerging knowledge of the nature of complex traits. Recent interest in systems biology as a unifying approach indicates a reawakened acceptance of the complexity of complex traits, though the temptation is to replace “gene for” thinking by comparably reductionistic “network for” concepts. Both approaches implicitly mix concepts of variants and invariants in genetics. Even the basic question is unclear: what does one need to know to “understand” the genetic basis of complex traits? New operational ideas about how to deal with biological complexity are needed.
Mammalian fertilization: the strange case of sperm protein 56
Authors: Wassarman Paul M.
Published: February 2009

During mammalian fertilization sperm bind to the egg's zona pellucida (ZP) after undergoing capacitation. Capacitated mouse sperm bind to mZP3 (one of three ZP glycoproteins), undergo the acrosome reaction, penetrate the ZP, and fuse with egg plasma membrane. Sperm protein 56 (sp56), a member of the C3/C4 superfamily of binding proteins, was identified nearly 20 years ago as a binding partner for mZP3 by photoaffinity cross‐linking of acrosome‐intact sperm. However, subsequent research revealed that sp56 is a component of the sperm's acrosomal matrix and, for sperm with an intact acrosome, should be unavailable for binding to mZP3. Recently, this dilemma was resolved when it was recognized that some acrosomal matrix (AM) proteins, including sp56, are released to the sperm surface during capacitation. This may explain why uncapacitated mammalian sperm are unable to bind to the unfertilized egg ZP.
Thermodynamic analysis of biodegradation pathways
Authors: Finley Stacey D. , Broadbelt Linda J. , Hatzimanikatis Vassily
Published: February 2009

Microorganisms provide a wealth of biodegradative potential in the reduction and elimination of xenobiotic compounds in the environment. One useful metric to evaluate potential biodegradation pathways is thermodynamic feasibility. However, experimental data for the thermodynamic properties of xenobiotics is scarce. The present work uses a group contribution method to study the thermodynamic properties of the University of Minnesota Biocatalysis/Biodegradation Database. The Gibbs free energies of formation and reaction are estimated for 914 compounds (81%) and 902 reactions (75%), respectively, in the database. The reactions are classified based on the minimum and maximum Gibbs free energy values, which accounts for uncertainty in the free energy estimates and a feasible concentration range relevant to biodegradation. Using the free energy estimates, the cumulative free energy change of 89 biodegradation pathways (51%) in the database could be estimated. A comparison of the likelihood of the biotransformation rules in the Pathway Prediction System and their thermodynamic feasibility was then carried out. This analysis revealed that when evaluating the feasibility of biodegradation pathways, it is important to consider the thermodynamic topology of the reactions in the context of the complete pathway. Group contribution is shown to be a viable tool for estimating, a priori, the thermodynamic feasibility and the relative likelihood of alternative biodegradation reactions. This work offers a useful tool to a broad range of researchers interested in estimating the feasibility of the reactions in existing or novel biodegradation pathways. Biotechnol. Bioeng. 2009;103: 532–541. © 2009 Wiley Periodicals, Inc.
Stem cells in microfluidics
Authors: van Noort Danny , Ong Siew Min , Zhang Chi , Zhang Shufang , Arooz Talha , Yu Hanry
Published: February 2009

With the introduction of microtechnology and microfluidic platforms for cell culture, stem cell research can be put into a new context. Inside microfluidics, microenvironments can be more precisely controlled and their influence on cell fate studied. Microfluidic devices can be made transparent and the cells monitored real time by imaging, using fluorescence markers to probe cell functions and cell fate. This article gives a perspective on the yet untapped utility of microfluidic devices for stem cell research. It will guide the biologists through some basic microtechnology and the application of microfluidics to cell research, as well as highlight to the engineers the cell culture capabilities of microfluidics. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Selective monosulfoxidation of tetrathiafulvalenes into chiral TTF‐sulfoxides
Authors: Chas Marcos , Riobé François , Sancho Raquel , Minguíllon Cristina , Avarvari Narcis
Published: February 2009

Four inner tetrathiafulvalene‐sulfoxides have been synthesized upon reaction of tetrathiafulvalene (TTF), tetramethyl‐tetrathiafulvalene (TMTTF), tetrakis (thiomethyl)‐tetrathiafulvalene (TMT‐TTF), and bis(ethylenedithio)‐tetrathiafulvalene (BEDT‐TTF) with enantiopure (+) or (−)‐(8,8‐dichlorocamphorylsulfonyl)‐oxaziridine as oxidizing agent. Chiral HPLC studies indicate very weak enantioselectivities for TTF‐SO 3 and TMTTF‐SO 4, formation of racemic mixture in the case of TMT‐TTF‐SO 5, and a rather good selectivity, up to 44% ee, in the case of BEDT‐TTF‐SO 1. The solid state structures of TMTTF‐SO 4 and TMT‐TTF‐SO 5 have been determined by single crystal X‐ray diffraction. Both compounds crystallize as racemates in the centrosymmetric triclinic space group P‐1. Theoretical calculations at DFT/B3LYP/6‐31+G* level afford optimized geometries in good accordance with the experimental structures and emphasize the participation of the chiral sulfoxide group in HOMO and LUMO. Time‐dependent DFT calculations corroborated with electronic circular dichroism spectra allow the assignment of the absolute configuration (R) for the major enantiomer of 1 when the (+)‐sulfonyl‐oxaziridine is used as oxygen transfer reagent. Preliminary semipreparative HPLC separation provided enantioenriched fractions up to 63% ee. Chirality, 2009. © 2009 Wiley‐Liss, Inc.
Diastereomeric resolution of p‐chloromandelic acid with (R)‐phenylethylamine
Authors: He Quan , Peng Yang‐Feng , Rohani Sohrab
Published: February 2009

The optical resolution of p‐chloromandelic acid using (R)‐α‐phenylethylamine as resolving agent was presented. The effect of solvents, molar ratio of racemate to the resolving agent, filtration temperature as well as the amount of solvent on resolution was investigated by orthogonal experimentation. The binary melting point phase diagram and crystal structure analysis of diastereomeric salts rationalized the success of the resolution. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Bistable traveling waves around an obstacle
Authors: Berestycki Henri , Matano Hiroshi , Hamel François
Published: February 2009

We consider traveling waves for a nonlinear diffusion equation with a bistable or multistable nonlinearity. The goal is to study how a planar traveling front interacts with a compact obstacle that is placed in the middle of the space ℝN. As a first step, we prove the existence and uniqueness of an entire solution that behaves like a planar wave front approaching from infinity and eventually reaching the obstacle. This causes disturbance on the shape of the front, but we show that the solution will gradually recover its planar wave profile and continue to propagate in the same direction, leaving the obstacle behind. Whether the recovery is uniform in space is shown to depend on the shape of the obstacle. © 2008 Wiley Periodicals, Inc.
Temperature Dependence of the Dielectric Properties and Dynamics of Ionic Liquids
Authors: Hunger Johannes , Stoppa Alexander , Schrödle Simon , Hefter Glenn , Buchner Richard
Published: February 2009

No solo dancers: The temperature dependence of dielectric spectra suggests that the lower‐frequency relaxation dominating the dynamics of imidazolium‐based room temperature ionic liquids cannot be solely due to independent rotational diffusion of the cations (see picture), but must also include cooperative motions of the surrounding particles.

magnified image

Dielectric spectra were measured for eight, mostly imidazolium‐based, room temperature ionic liquids (RTILs) over a wide range of frequencies (0.2≤ν/GHz≤89) and temperatures (5≤θ/°C≤ 65). Detailed analysis of the spectra shows that the dominant low frequency process centred at ca. 0.06 to 10 GHz (depending on the salt and the temperature) is better described using a symmetrically broadened Cole–Cole model rather than the asymmetric Cole–Davidson models used previously. Evaluation of the temperature dependence of the static permittivities, effective dipole moments, volumes of rotation, activation energies, and relaxation times derived from the dielectric data indicates that the low frequency process cannot be solely due to rotational diffusion of the dipolar imidazolium cations, as has been thought, but must also include other contributions, probably from cooperative motions. Analysis of the Debye process observed at higher frequencies for these RTILs is not undertaken because it overlaps with even faster processes that lie outside the range of the present instrumentation.
The reductionist blind spot
Authors: Abbott Russ
Published: February 2009

Can there be higher level laws of nature even though everything is reducible to the fundamental laws of physics? The computer science notion of level of abstraction explains how there can be. The key relationship between elements on different levels of abstraction is not the is‐composed‐of relationship but the implements relationship. I take a scientific realist position with respect to (material) levels of abstraction and their instantiation as (material) entities. They exist as objective elements of nature. Reducing them away to lower order phenomena produces a reductionist blind spot and is bad science. © 2009 Wiley Periodicals, Inc. Complexity, 2009.
Multi‐factors oriented study of P2P Churn
Authors: Yang Dong , Zhang Yu‐xiang , Zhang Hong‐ke , Wu Tin‐Yu , Chao Han‐Chieh
Published: February 2009

The dynamics of peers, namely Churn, is an inherent property of peer‐to‐peer (P2P) systems and is critical to their design and evaluation. Although every excellent P2P protocol has some solution to this issue, studies on Churn are still seldom. This paper studies various factors related to Churn, and uses them to analyze and evaluate P2P protocols. Prior researches on Churn are all based on the P2P network factors in Churn environment, and their difference is whether to use these factors as predecessor references to build Churn analytical models or as successor references to test the models. According to this difference, this paper first divides various factors into two categories: impacting Churn and affected by Churn. There is a causal relationship between these two categories. Factors impacting Churn are cause, and the factors affected by Churn are effect. In this paper, we use this causality to simulate and analyze P2P Churn. Cause is used as the input data and effect is used as the output result. Second, based on the classification of Churn factors, we present a performance evaluation framework and two comparing models. Based on the framework and models, we simulate and analyze three P2P protocols and get some useful results such as the performance of these protocols under Churn, the advantage of Chord over others, and the most important factors impacting Churn. Finally, we present a method to improve recent P2P Churn models by adding some influence factors. Copyright © 2009 John Wiley & Sons, Ltd.
Review of the effects of 17α‐estradiol in humans: a less feminizing estrogen with neuroprotective potential
Authors: Moos Walter H. , Dykens James A. , Nohynek Dana , Rubinchik Evelina , Howell Neil
Published: February 2009

17α‐Estradiol is a less feminizing isomer of the potent hormonal estrogen, 17β‐estradiol. 17α‐Estradiol is an orally active small molecule with conflicting reports of efficacy in preclinical models of degenerative diseases. A number of studies suggest neuroprotective potential in human neurodegenerative disorders, including Alzheimer's disease (AD) and Parkinson's disease. Several studies have established an antioxidant effect of 17α‐estradiol in humans. The sodium salt of 17α‐estradiol 3‐sulfate is a minor component (2.5–9.5%) of several widely marketed estrogen hormone replacement products, such as Premarin®, that are approved by the U.S. Food and Drug Administration and have been prescribed and studied in women and men for more than 65 years. Most of the more than 100 published reports on the neurological effects of feminizing estrogens found positive responses in at least one measure relating to cognition or prevention and treatment of AD, notwithstanding the negative results in the Women's Health Initiative studies. Whether these limited, and often not statistically significant, findings are clinically meaningful remains unknown. In many in vitro and in vivo preclinical neuroprotection and related studies, 17α‐estradiol and 17β‐estradiol are active at similar concentrations and doses. However, 17α‐estradiol is less pleiotropic than 17β‐estradiol, and thus its potential toxicity might be lower. Given decades of mixed reports regarding the potential efficacy and safety of strongly feminizing hormones in neurodegenerative diseases, the weakly feminizing 17α‐estradiol might be a suitable candidate for clinical testing of the neuroprotective potential of this chemical class because it avoids, or significantly reduces, the adverse effects of potent hormonal compounds. Drug Dev Res 70:1–21, 2009. © 2009 Wiley‐Liss, Inc.
Prevalence and correlates of exercise motivated by negative affect
Authors: De Young Kyle P. , Anderson Drew A.
Published: February 2009

Objective

The purpose of this study was to determine the prevalence and correlates of exercising in response to negative affect.

Method

Participants (N = 177) completed questionnaires assessing affect before and after exercise, exercise quality and quantity, eating behaviors and attitudes, body image, and self‐esteem.

Results

Fifty‐eight percent of participants endorsed ever exercising in response to negative affect. As a group, these individuals were more likely to report self‐induced vomiting, binge eating, and fasting over the previous 4 weeks. They also showed poorer body image and self‐esteem, and their exercise was more obligatory and impairing. Groups did not differ on body mass index or quantity of exercise.

Discussion

Negative affect motivated exercise appears to be a common phenomenon that is associated with eating disordered behavior. © 2009 by Wiley Periodicals, Inc. Int J Eat Disord 2010
Nonionic surfactant‐capped gold nanoparticles for selective enrichment of aminothiols prior to CE with UV absorption detection
Authors: Li Mu‐De , Cheng Tian‐Lu , Tseng Wei‐Lung
Published: February 2009

In this study, we describe the use of Tween 20‐capped gold nanoparticles (AuNPs) as selective probes for the extraction of aminothiols from an aqueous solution. Tween 20 molecules noncovalently attached to the surface of AuNPs to form Tween 20–AuNPs were used for the selective extraction of aminothiols through the formation of Au–S bonds. After extraction and centrifugation, the aminothiols were detached from the surface of the AuNPs by adding DTT in a high concentration. We used this probe in combination with CE and UV absorption detection. On‐line concentration and separation of the released aminothiols were performed by using 1.6% v/v poly(diallyldimethylammonium chloride) as an additive in CE. Under optimal extraction and stacking conditions, the LOD at a S/N of 3 were 28, 554, and 456 nM for glutathione (GSH), cysteine (Cys), and homocysteine (HCys), respectively. In comparison with the normal injection without the extraction procedure, approximately 2280‐, 998‐, and 904‐fold improvements in the sensitivity were observed for GSH, Cys, and HCys, respectively. We have validated the application of our method on the basis of the analysis of GSH and HCys in human urine samples. It is believed that this approach has significant potential to be extended to clinical diagnosis.