bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection and identification of 4‐hydroxy‐2‐nonenal Schiff‐base adducts along with products of Michael addition using data‐dependent neutral loss‐driven MS3 acquisition: Method evaluation through an in vitro study on cytochrome c oxidase modifications
Authors: Rauniyar Navin , Prokai Laszlo
Published: September 2009

We report a data‐dependent neutral‐loss‐driven MS3 acquisition to enhance, in addition to abundant Michael adducts, the detection of Schiff‐base adducts of proteins and 4‐hydroxy‐2‐nonenal, a reactive end product of lipid peroxidation. In vitro modification of cytochrome c oxidase, a mitochondrial protein complex, was used as a model to evaluate the method. The technique allowed for a confident validation of modification sites and also identified a Schiff‐base adduct in subunit Vb of the protein complex.
Comparative analysis of OFFGel, strong cation exchange with pH gradient, and RP at high pH for first‐dimensional separation of peptides from a membrane‐enriched protein fraction
Authors: Manadas Bruno , English Jane A. , Wynne Kieran J. , Cotter David R. , Dunn Michael J.
Published: September 2009

The analysis and quantitation of membrane proteins have proved challenging for proteomics. Although several approaches have been introduced to complement gel‐based analysis of intact proteins, the literature is rather limited in comparing major emerging approaches. Peptide fractionation using IEF (OFFGel), strong cation exchange HPLC using a pH gradient (SCX‐pG), and RP HPLC at high pH, have been shown to increase peptide and protein identification over classic MudPIT approaches. This article compares these three approaches for first‐dimensional separation of peptides using a detergent phase (Triton X‐114) enriched membrane fraction from mouse cortical brain tissue. Results indicate that RP at high pH (pH 10) was superior for the identification of more peptides and proteins in comparison to the OFFGel or the SCX‐pG approaches. In addition, gene ontology analysis (GOMiner) revealed that RP at high pH (pH 10) successfully identified an increased number of proteins with “membrane” ontology, further confirming its suitability for membrane protein analysis, in comparison to SCX‐pG and OFFGel techniques.
Localized network centrality and essentiality in the yeast–protein interaction network
Authors: Park Keunwan , Kim Dongsup
Published: September 2009

It has been suggested that a close relationship exists between gene essentiality and network centrality in protein–protein interaction networks. However, recent studies have reported somewhat conflicting results on this relationship. In this study, we investigated whether essential proteins could be inferred from network centrality alone. In addition, we determined which centrality measures describe the essentiality well. For this analysis, we devised new local centrality measures based on several well‐known centrality measures to more precisely describe the connection between network topology and essentiality. We examined two recent yeast protein–protein interaction networks using 40 different centrality measures. We discovered a close relationship between the path‐based localized information centrality and gene essentiality, which suggested underlying topological features that represent essentiality. We propose that two important features of the localized information centrality (proper representation of environmental complexity and the consideration of local sub‐networks) are the key factors that reveal essentiality. In addition, a random forest classifier showed reasonable performance at classifying essential proteins. Finally, the results of clustering analysis using centrality measures indicate that some network clusters are closely related with both particular biological processes and essentiality, suggesting that functionally related proteins tend to share similar network properties.
Intermolecular π‐dimer of oxoverdazyl radicals with long‐distance multicenter (2e/8c) bonding via nitrogen atoms
Authors: Rosokha Sergiy V. , Zhang Jing , Lu Jianjiang , Kochi Jay K.
Published: September 2009

The 1,5‐dimethyl‐6‐oxoverdazyl radical's solid‐state structure shows distinct π‐dimeric units with close interplanar separations (3.10 Å) between the head‐over‐tail cofacial moieties and several interatomic contacts shorter than the sums of the van der Waals radii. Evaluations of the frontier orbitals of monomeric oxoverdazyl and its π‐dimer reveal that interaction of the radical SOMOs (concentrated on the nitrogen atoms) leads to the formation of the supramolecular orbital involving four equivalent bonding (N…N) segments between two oxoverdazyl moieties. As such, this π‐dimer represents a rare example of nitrogen‐based multicenter (2e/8c) long‐distance bonding and emphasizes the universal character of this phenomenon in organic (ion‐) radical systems. Copyright © 2009 John Wiley & Sons, Ltd.
Entanglement and symmetry effects in the transition to the Schrödinger cat regime
Authors: de Pasquale F. , Giorgi G.L. , Zannetti M.
Published: September 2009

We study two‐spin entanglement and order parameter fluctuations as a function of the system size in the XY model in a transverse field and in the isotropic XXX model. Both models are characterized by the occurrence of ground state degeneracy also when systems of finite size are considered. This is always true for the XXX model, but only at the factorizing field for the XY model. We study the size dependence of symmetric states, which, in the presence of degeneracy, can be expanded as a linear combination of broken symmetry states. We show that, while the XY model looses its quantum superposition content exponentially with the size N, a decrease of the order of 1 / N is observed when the XXX model is considered. The emergence of two qualitatively different regimes is directly related to the difference in the symmetry of the models.
Combating plant diseases—the Darwin connection
Authors: Hollomon Derek W , Brent Keith J
Published: September 2009

Although Darwin knew of plant diseases, he did not study them as part of his analysis of natural selection. Effective plant disease control has only been developed after his death. This article explores the relevance of Darwin's ideas to three problem areas with respect to diseases caused by fungi: emergence of new diseases, loss of disease resistance bred into plants and development of fungicide resistance. Darwin's concept of change through natural or artificial selection relied on selection of many small changes, but subsequent genetic research has shown that change can also occur through large steps. Appearance of new diseases can involve gene duplication, transfer or recombination, but all evidence points to both host plant resistance and fungicide susceptibility being overcome through point mutations. Because the population size of diseases such as rusts and powdery and downy mildews is so large, all possible point mutations are likely to occur daily, even during moderate epidemics. Overcoming control measures therefore reflects the overall fitness of these mutants, and much resource effort is being directed towards assessment of their fitness, both in the presence and in the absence of selection. While recent developments in comparative genomics have caused some revision of Darwin's ideas, experience in managing plant disease control measures clearly demonstrates the relevance of concepts he introduced 150 years ago. It also reveals the remarkable speed and the practical impact of adaptation in wild microorganism populations to changes in their environment, and the difficulty of stopping or delaying such adaptation. Copyright © 2009 Society of Chemical Industry
Enhancement of magnetoimpedance effect in Co‐based amorphous ribbon with a meander structure
Authors: Chen Lei , Zhou Yong , Lei Chong , Zhou Zhi‐Min , Ding Wen
Published: September 2009

A model for the enhanced giant magnetoimpedance (GMI) effect in field‐annealed Co‐based ribbon with a meander structure is developed. Three different kinds of ribbon are fabricated by a MEMS method and the field dependence of the GMI effect is measured at 10 MHz. Good agreement between theory and experiment shows the validity of this model. A larger change of inductance L in the meander structure results in the increasing of impedance Z and the enhanced GMI effect.
Two‐ and three‐dimensional profilometer assessments to determine titanium roughness
Authors: Canabarro A. , Figueiredo F. , Paciornik S. , De‐Deus G.
Published: September 2009

In this study, a comparative topography analysis of titanium (Ti) surfaces was performed using two‐ (2D) and three‐dimensional (3D) profilometers. Ti samples were either only sandblasted (SB) using Al2O3 particles or were SB and received an additional chemical treatment using a solution of 4% HF (SLA). Samples with no treatment were used as a control group (C). Therefore, three different surfaces were evaluated: SB, SLA and C. The Ti surface topographies were evaluated by scanning electron microscopy. An Ra roughness measurement was performed on each Ti sample by 2D and 3D profilometers. Surface roughness was also characterized using amplitude, spatial and hybrid 3D parameters. 2D and 3D profilometer analyses produced very close results. Mean Ra values range from 0.19 to 0.25 (C, p<0.05), 0.84 to 0.99 (SLA, p<0.05) and 0.98 to 1 µm (SB, p>0.05). The statistically different Ra values depending on the surface studied may be explained by methodological and technical differences. Also, 3D profilometer seems to be the more appropriate analytical method for measuring the roughness of Ti surfaces because it also describes surface organization. SCANNING 31: 174–179, 2009. © 2009 Wiley Periodicals, Inc.
The impact of key assignment on VANET privacy
Authors: Haas Jason J. , Hu Yih‐Chun , Laberteaux Kenneth P.
Published: September 2009

There are two underlying principles that guide how a vehicular ad hoc network (VANET) is built: there will be misbehavior and the extent to which vehicles can misbehave should be bounded. Additionally, the main use for VANETs currently is to enable safety applications where vehicles' position, velocity, and acceleration are broadcast to other vehicles in the VANET. Combining these guiding principles with this application results in the privacy of vehicles and users being an important concern for VANET design. Safety application messages are signed using keys and therefore linked to vehicles. In this work, we investigate how to assign keys to vehicles in order to preserve privacy and maintain our guiding VANET design principles. Specifically, we investigate the design space where individual keys may be given to multiple vehicles and vehicles may have multiple keys. Through a simple security analysis, we eliminate the case where all keys are common. Through mathematical and logical analysis, we conclude that keys should not be owned by multiple vehicles, that is, keys should be unique to vehicles and vehicles should be given multiple keys. Specifically, we show that it is impossible to provide good privacy and fast revocation when keys are shared among vehicles. Copyright © 2009 John Wiley & Sons, Ltd.
BHIDS: a new, cluster based algorithm for black hole IDS
Authors: Roy Debdutta Barman , Chaki Rituparna , Chaki Nabendu
Published: September 2009

Mobilead hocnetworks (MANET) are highly vulnerable to attacks due to multiple factors including the open medium, dynamically changing network topology, cooperative algorithms, and lack of centralized monitoring. Besides slowing down the network, the traditional way of using firewalls and cryptography often fails to detect different types of attacks. The lack of infrastructures in MANETs makes the detection and control of security hazards all the more difficult. In this paper, we present a new, cluster based Black Hole Intrusion Detection System (BHIDS) for mobile,ad hocnetworks. The features that are considered for BHIDS include mobility of nodes, variation in number of attacking nodes, packet delivery rate, density of the network, etc. The nodes in the network form a two‐layered cluster. This helps splitting the processing and communication overhead between the cluster heads at Layer 1 and 2. The proposed IDS algorithm has been tested on a simulated network using the NS simulator. The performance graphs show marked improvement as far as packet dropping is concerned. Copyright © 2009 John Wiley & Sons, Ltd.
Tuning the Electrical Properties of Si Nanowire Field‐Effect Transistors by Molecular Engineering
Authors: Bashouti Muhammad Y. , Tung Raymond T. , Haick Hossam
Published: September 2009

Exposed facets of n‐type silicon nanowires (Si NWs) fabricated by a top‐down approach are successfully terminated with different organic functionalities, including 1,3‐dioxan‐2‐ethyl, butyl, allyl, and propyl‐alcohol, using a two‐step chlorination/alkylation method. X‐ray photoemission spectroscopy and spectroscopic ellipsometry establish the bonding and the coverage of these molecular layers. Field‐effect transistors fabricated from these Si NWs displayed characteristics that depended critically on the type of molecular termination. Without molecules the source–drain conduction is unable to be turned off by negative gate voltages as large as −20 V. Upon adsorption of organic molecules there is an observed increase in the “on” current at large positive gate voltages and also a reduction, by several orders of magnitude, of the “off” current at large negative gate voltages. The zero‐gate voltage transconductance of molecule‐terminated Si NW correlates with the type of organic molecule. Adsorption of butyl and 1,3‐dioxan‐2‐ethyl molecules improves the channel conductance over that of the original SiO2Si NW, while adsorption of molecules with propyl‐alcohol leads to a reduction. It is shown that a simple assumption based on the possible creation of surface states alongside the attachment of molecules may lead to a qualitative explanation of these electrical characteristics. The possibility and potential implications of modifying semiconductor devices by tuning the distribution of surface states via the functionality of attached molecules are discussed.
A cross‐layer partner‐assisted handoff scheme for hierarchical mobile IPv6 in IEEE 802.16e systems
Authors: Chen Yuh‐Shyan , Wu Kun‐Lin
Published: September 2009

The design of the seamless handoff is the key issue in the next‐generation mobile networks. A new broadband wireless access, called WiMAX, has been specified in the IEEE 802.16e standard document, to provide the high bandwidth and the large coverage area than the IEEE 802.11‐based wireless networks. In the IP‐based mobile network, mobile IPv6 (MIPv6) protocol provides the binding update message to update the mobile station's IP information for supporting the layer 3 mobility. Hierarchical mobile IPv6 (HMIPv6) protocol is proposed by employing a hierarchical network structure to reduce handoff latency. HMIPv6 protocol suffers the long handoff delay and the high packet lost in the macro mobility. This paper presents a new cross‐layer partner‐assisted handoff mechanism based on HMIPv6, termed as P_HMIPv6 protocol. The P_HMIPv6 protocol is a cross‐layer approach by the combination of layer 2 and layer 3. The partner station (PS) is a new component with relay ability and adopted by our protocol. With the assistance of the PS, care‐of address (CoA) is pre‐acquired and DAD operation is pre‐executed by the PS before the MS initiates the layer 2 handoff. The simulation results show that P_HMIPv6 protocol actually achieves the performance improvements in handoff delay time, packet loss rate, and handoff delay jitter. Copyright © 2009 John Wiley & Sons, Ltd.
Simulations and experiments for optimal deployment of an RFID‐based location‐aware system
Authors: Hsu Pang‐Wei , Lin Tzong‐Huei , Chang Herbert H. , Chen Yu‐Ting , Tseng Yin‐Jiun , Hsiao Chia‐Hung , Chan Chia‐Tai , Chiu Hung‐Wen , Yen David Hung‐Tsang , Chen Po‐Chou , Chu Woei‐Chyn
Published: September 2009

The proliferation of communication and mobile computing devices and local‐area wireless networks has cultivated a growing interest in location‐aware systems and services. An essential problem in location‐aware computing is the determination of physical locations. RFID technologies are gaining much attention, as they are attractive solutions to indoor localization in many healthcare applications. In this paper, we propose a new indoor localization methodology that aims to deploying RFID technologies in achieving accurate location‐aware undertakings with real‐time computation. The proposed algorithm introduces means to improve the accuracy of the received RF signals. Optimal settings for the parameters in terms of reader and reference tag properties were investigated through simulations and experiments. The experimental results indicate that our indoor localization methodology is promising in applications that require fast installation, low cost and high accuracy. Copyright © 2009 John Wiley & Sons, Ltd.
Use of Botulinum Toxin Type A Before Abdominal Wall Hernia Reconstruction
Authors: Ibarra‐Hurtado Tomas R. , Nuño‐Guzmán Carlos M. , Echeagaray‐Herrera Jorge E. , Robles‐Vélez Everardo , de Jesús González‐Jaime José
Published: September 2009

Background

Abdominal wall hernia repair after open abdomen management represents a surgical challenge, particularly due to muscle tension and lateral retraction. This study was designed to propose the use of Botulinum Toxin Type A (BTA) before abdominal wall hernia repair.

Methods

A prospective study of patients with abdominal wall hernia after open abdomen management was undertaken between September 2007 and January 2009. Bilateral BTA application was performed under electromyographic guidance at the abdominal wall. Transverse abdominal wall defect measurement was practiced at weekly intervals: clinically, in the first two patients, and with CT scan in the following 10 patients. Surgical closure was scheduled if no further hernia defect reduction was noted. Patients were followed at monthly hospital visits.

Results

In the first two patients, a hernia defect reduction of 50 and 47.2%, respectively, was documented by the third week after BTA application, with no further reduction. In the 10 patients under CT scan hernia defect measurement, when comparing the initial mean transverse defect measure and at 4 weeks after BTA application (13.85 ± 1.49 cm vs. 8.6 ± 2.07 cm), an overall mean reduction of 5.25 ± 2.32 cm was observed (p < 0.001; 95% confidence interval, 3.59–6.91). Hernia repair was performed, with no recurrences at a mean follow‐up of 9.08 months.

Conclusions

BTA application before abdominal wall hernia repair seems to be useful. The lateral muscles paralysis achieved and transverse hernia defect reduction allows a minimal tension closure. To our knowledge, this is the first report of BTA application before abdominal wall hernia reconstruction.
Experience with Reversed L‐Shaped Incision for Right Hemicolectomy Combined with Liver Resection
Authors: Hsu Kuo‐Feng , Yu Jyh‐Cherng , Chen Teng‐Wei , Jao Shu‐Wen , Chan De‐Chuan , Chen Cheng‐Jueng , Shih Ming‐Lang , Liu Yao‐Chi , Fu Chun‐Yu , Hsieh Chung‐Bao
Published: September 2009

Background

Various types of incisions have been applied in simultaneous resections of colorectal cancer and synchronous liver metastases. We describe our experience with the reversed L‐shaped incision for simultaneous right hemicolectomy and liver resection.

Methods

We applied the reversed L‐shaped incision in nine patients who underwent simultaneous right hemicolectomy and right liver resection or left hepatectomy. A reversed L‐shaped incision of the abdomen was consisted of midline and transverse incisions with the junction of the umbilicus. The operative field was kept open using Kent retractors. First, right colon mobilization was performed easily and right hemicolectomy was performed. Subsequently, liver mobilization with identification of hepatic vessels was achieved and right liver resection or left hepatectomy was performed.

Results

The reversed L‐shaped incision successfully provided a good and rapid exposure in nine patients. There were no complications, such as wound infection, lung atelectasis/pneumonia, or incisional hernia, in patients with the reversed L‐shaped incision.

Conclusions

Our preliminary experience demonstrated that the reversed L‐shaped incision might be a good choice in a subset of patients with simultaneous right hemicolectomy and right liver resection or left hepatectomy. However, a large, prospective, controlled study comparing different incision types in the same procedure with variables, such as operating time, postoperative pain scores, patient’s satisfaction, and postoperative complication, is needed to support the benefit of the reversed L‐shaped incision.
Retromammary Approach for Endoscopic Resection of Benign Breast Lesions
Authors: Liu Hsien , Huang Chih‐Kun , Yu Po‐Chin , Chen Hsin‐Pao , Hsieh Pei‐Min , Hung Kao‐Chen , Hung Chao‐Ming , Chen Yaw‐Sen
Published: September 2009

Background

One of the merits of endoscopic surgery is that it can be performed through small remote incisions made in inconspicuous areas. To improve cosmetic outcomes of surgical treatment of benign breast lesions, we performed endoscopic surgery through minimally sized axillary incisions with the goal of achieving scar‐free breasts.

Methods

From August 2007 to August 2008, 18 patients with 20 benign breast lesions underwent endoscopic breast excision in our institution. Endoscopic resection of benign breast lesions was performed via the retromammary route with video assistance. Cosmetic results were evaluated using the five‐item, four‐step ABNSW scoring system, assessing breast asymmetry, breast shape, nipple shape, skin condition, and wound scars.

Results

The median age of the patients was 27 years (IQR 23.0, 29.0). Median resected lesion size was 3.3 cm (IQR 2.9, 3.9). Median operative time was 85.0 min (IQR 70.0, 100.0). A marginally significant difference in operative times was noted between fibroadenoma and/or juvenile fibroadenoma cases and mastopathy or benign phyllodes cases (80.0 vs. 100.0; p < 0.06). Median total ABNSW score was 14 points. Postoperatively, 5 patients had mild local subcutaneous emphysema, and one had transient brachial palsy. No breast ecchymosis or deformity was noted. No major complications developed in any patient, and 89% of patients had good or excellent results.

Conclusions

Video‐assisted endoscopic breast surgery has changed routine breast surgery, manifesting cosmetic effects that cannot be achieved by previous routine surgical techniques. Patients with multiple or large benign tumors who desire excellent cosmetic results are good candidates for this approach.
A Phase I Study of Intraoperative Radiotherapy for Early Breast Cancer in Japan
Authors: Sawaki Masataka , Sato Shigenori , Kikumori Toyone , Ishihara Shunichi , Aoyama Yuichi , Itoh Yoshiyuki , Nakao Akimasa , Imai Tsuneo
Published: September 2009

Background

The present study was designed to identify the optimal intraoperative radiotherapy (IORT) dose for early breast cancer in Japanese women.

Methods

A phase I study was designed using a scheme of dose‐escalation from 19, 20, and 21 Gy at 90% isodose. The primary endpoint was early toxicity. Secondary endpoints were efficacy for a long period and late toxicity. Inclusion criteria were as follows: (1) tumor size <2.5 cm, (2) age >50 years, (3) surgical margin >1 cm, (4) intraoperative pathologically free margins, (5) written informed consent. Exclusion criteria were (1) contraindication to radiation therapy, (2) extensive intraductal component. Partial resection was performed with at least a 1‐cm margin around the tumor. Radiation was delivered directly to the mammary gland employing a MOBETRON device. Toxicity was evaluated with the Common Terminology Criteria for Adverse Events (CTCAE), version 3.0.

Results

From December 2007 to September 2008, 9 patients were enrolled in the study. The first three patients received a radiation dose of 19 Gy. Within 3 months toxicity in each case was deep connective tissue fibrosis (grade 1: 2/3, grade 2: 1/3). The next three patients received a dose of 20 Gy and had toxicities of deep connective tissue fibrosis (grade 1: 3/3), hematoma (grade 1: 2/3), infection in the musculoskeletal soft tissue (grade 1: 2/3), and soft tissue necrosis (grade 2: 1/3). The final three patients received a dose of 21 Gy and had toxicities of deep connective tissue fibrosis (grade 1: 2/3), hematoma (grade 1: 1/3), infection in the musculoskeletal soft tissue (grade 1: 1/3), and soft tissue necrosis (grade 2: 2/3).

Conclusions

The IORT treatment was tolerated very well in Japanese women, and we now recommend the dose of 21 Gy.
Chronic Schistosomiasis Japonica is an Independent Adverse Prognostic Factor for Survival in Hepatocellular Carcinoma Patients Who Have Undergone Hepatic Resection: Clinicopathological and Prognostic Analysis of 198 Consecutive Patients
Authors: Matsuda Masanori , Fujii Hideki
Published: September 2009

Background

The present study was carried out to clarify the clinicopathological features of hepatocellular carcinoma (HCC) patients with chronic schistosomiasis japonica (SJ) who underwent hepatic resection. Furthermore, we also analyzed the impact of chronic SJ on survival after hepatic resection.

Methods

During the last 10 years in our department, 198 patients have undergone hepatic resection for HCC. Forty‐four patients were diagnosed as having chronic SJ by histological examination. Clinicopathological features and survival were retrospectively analyzed.

Results

Age in the SJ group was significantly higher than in the non‐SJ group. In the SJ group, positivity to HBsAg (hepatitis B surface antigen) was significantly lower than in the non‐SJ group, and patients more often developed intrahepatic cholangiocellular carcinoma (or cholangiolocellular carcinoma) than in the non‐SJ group. Greatest tumor dimension in the SJ group was significantly larger than in the non‐SJ group. Univariate analysis revealed that chronic SJ, prothrombin time 80% or less and Child‐Pugh B, des‐γ‐carboxyprothrombin (DCP) level >40 milli‐arbitrary units (mAU)/ml, tumor diameter of more than 5.0 cm, multiple tumors, vascular invasion, intrahepatic metastasis, advanced T stage (T2–4), and non‐curative resection were associated with significantly worse overall survival. By multivariate analysis, chronic SJ, Child‐Pugh B, advanced T stage, and non‐curative resection were independent predictors of the adverse overall survival of HCC patients after hepatic resection.

Conclusions

Patients with chronic SJ were older, had larger HCC, and were more often complicated by cholangiocellular carcinoma (or cholangiolocellular carcinoma) than non‐SJ patients. Chronic SJ was an independent adverse prognostic factor for survival after hepatic resection in HCC patients.
Conversion of Glenohumeral Fusion to Total Shoulder Arthroplasty for Scapulothoracic Pain: Case Report and Surgical Technique
Authors: Nho Shane J. , Garbis Nickolas , Reiff Stefanie , Terry Allison , Shindelar Sheri , Romeo Anthony A.
Published: September 2009

There are several references in the hip and knee literature that mention converting fusions to a prosthetic total arthroplasty, but similar reports of total shoulder arthroplasty after glenohumeral fusion are lacking. The indication for conversion of a glenohumeral arthrodesis to a total shoulder arthroplasty is persistent periscapular pain refractory to conservative treatment. The purpose of the following article is to describe the preoperative plan and surgical technique in the conversion of a glenohumeral fusion to a total shoulder arthroplasty in single case of protracted scapulothoracic pain.
On Plate Identification of Coexisting Polyoxyethylene (20) Stearyl Ether, Cetyl Pyridinium Chloride, Tetradecyl Trimethyl Ammonium Bromide and Polyoxyethylene (9.5) Octyl Phenyl Ether Surfactants with Preliminary Separation by Planar Chromatography
Authors: Mohammad Ali , Bhawani Showkat Ahmad
Published: September 2009

Separation studies of four surfactants (nonionic and cationic) were performed on silica high‐performance thin‐layer chromatographic plates with various solvent systems. The most useful chromatographic system for the mutual separation of coexisting polyoxyethylene (20) stearyl ether (C18EO20), cetylpyridinium chloride (CPC), tetradecyl trimethyl ammonium bromide (TTAB) and polyoxyethylene (9.5), octyl phenyl ether (OPEO9.5) was formamide + 1 M formic acid (50:50 v/v). The nature of ‘H’ and ‘H+’ of formic acid (H–COO−H+) on the mobility of these surfactants was studied. The interference due to the presence of metal cations as impurities on the resolution of mixture of C18EO20, CPC, TTAB and OPEO9.5 was also examined. The limits of detection of C18EO20, CPC, TTAB and OPEO9.5 estimated were 0.0620, 0.0310, 0.0625 and 0.0312 μg/zone, respectively. The practical applicability of the proposed method was tested for the identification of four coexisting surfactants after their separation from the spiked aqueous systems.
Bloom Formation on Poorly‐Tempered Chocolate and Effects of Seed Addition
Authors: Kinta Yasuyoshi , Hartel Richard W.
Published: September 2009

Bloom on chocolate with different levels of cocoa butter seed addition was investigated. When insufficient cocoa butter seed crystals were added to give proper temper, the chocolate developed bloom as dark brown spheres in lighter color areas, similar to that seen in bloom on untempered chocolate. These dark colored spheres overlapped and the lighter color areas disappeared with increasing seed amount added. The relationship between seed amount and lighter color area (bloom), as quantified by image analysis, showed that over 270 ppm seeds (fat basis) were needed to accomplish good tempering. The cocoa butter crystallization behavior with various amounts of seed was observed by light microscopy. Too few seeds caused sparse β crystallization and massive β′ crystallization, which explains the appearance of poorly tempered chocolate bloom. As seed amount increased, β crystallization of cocoa butter took less time to reach the upper level of solid fat content and the size became smaller. In addition, DSC analysis was carried out to study crystallization and melting behavior of cocoa butter with different seed amounts. Higher levels of added seeds resulted in greater amounts of β crystal formation and the crystallization temperature increased, which meant crystallization occurred earlier. These results showed that the mechanism of bloom formation on poorly tempered chocolate (insufficient seeds) is due to sufficient time and space for phase (particles and fat) separation as the stable polymorphs grow.
Supplier–supplier relationships in buyer–supplier–supplier triads: Implications for supplier performance
Authors: Wu Zhaohui , Choi Thomas Y. , Rungtusanatham M. Johnny
Published: September 2009

A growing number of studies and evidence from industries suggest that, besides managing the relationship with its suppliers, a buyer needs to proactively manage the relationships between those suppliers. In a buyer–supplier–supplier relationship triad, the buyer, as the contracting entity, influences the suppliers’ behaviors and the relationship between them. By considering the relationships in such a triad, we are able to gain a richer and more realistic perspective of buyer–supplier relationships. In this study, our goal is to examine supplier–supplier relationships in buyer–supplier–supplier triads, focusing on how such relationships impact the supplier performance. We frame the supplier–supplier relationship as co‐opetition—one in which competing suppliers work together to meet the buyer's requirements. We investigate the role of the buyer on such relationships, and how the buyer and co‐opetitive supplier–supplier relationships affect supplier performance. We find mixed empirical support for our hypotheses. However, we are able to demonstrate the dynamics of supplier–supplier co‐opetition in the buyer–supplier–supplier triad. We point out the need for further studies in this area.
Damping mechanisms of internal waves in continuously stratified rotating basins
Authors: SHIMIZU K. , IMBERGER J.
Published: September 2009

Damping mechanisms, damping rates and the dissipative modal structure of internal waves in stratified rotating circular basins are investigated analytically. The damping is shown to be due to a combination of the internal-wave cancelling, where waves emitted by the oscillatory boundary layers destructively interact with the parent wave and drain energy from it, and spin-down modified by the periodicity, where the energy is drained by the sinks and sources at the bottom corner caused by a discontinuity in the Ekman transport. It is shown that super-inertial Poincaré waves and sub-inertial Kelvin waves are damped predominantly by the internal-wave cancelling and modified spin-down, respectively. These processes also modify the internal-wave structure; for super-inertial waves, the boundary-layer-generated waves intensify the interior flow in the lower part of the water column and delay the phase relative to the isopycnal displacements, but for sub-inertial waves, the Ekman pumping and the corner sinks and sources add a horizontal circular flow that slants the crest and trough backwards near the wall.
Structure and decay of rotating homogeneous turbulence
Authors: THIELE MARK , MÜLLER WOLF-CHRISTIAN
Published: September 2009

Navier–Stokes turbulence subject to solid-body rotation is studied by high-resolution direct numerical simulations (DNS) of freely decaying and stationary flows. Setups characterized by different Rossby numbers are considered. In agreement with experimental results strong rotation is found to lead to anisotropy of the direct nonlinear energy flux, which is attenuated primarily in the direction of the rotation axis. In decaying turbulence the evolution of kinetic energy follows an approximate power law with a distinct dependence of the decay exponent on the rotation frequency. A simple phenomenological relation between exponent and rotation rate reproduces this observation. Stationary turbulence driven by large-scale forcing exhibits k⊥−2-scaling in the rotation-dominated inertial range of the one-dimensional energy spectrum taken perpendicularly to the rotation axis. The self-similar scaling is shown to be the cumulative result of individual spectral contributions which, for low rotation rate, display k⊥−3-scaling near the k∥ = 0 plane. A phenomenology which incorporates the modification of the energy cascade by rotation is proposed. In the observed regime the nonlinear turbulent interactions are strongly influenced by rotation but not suppressed. Longitudinal two-point velocity structure functions taken perpendicularly to the axis of rotation indicate weak intermittency of the k∥ = 0 (2D) component of the flow while the intermittent scaling of k∥ ≠ 0 (3D) fluctuations is well captured by a modified She–Lévêque intermittency model which yields the expression ζp = p/6 + 2(1 − (2/3)p/2) for the structure function scaling exponents.
Diffusion and the formation of vorticity staircases in randomly strained two-dimensional vortices
Authors: TURNER MATTHEW R. , BASSOM ANDREW P. , GILBERT ANDREW D.
Published: September 2009

The spreading and diffusion of two-dimensional vortices subject to weak external random strain fields is examined. The response to such a field of given angular frequency depends on the profile of the vortex and can be calculated numerically. An effective diffusivity can be determined as a function of radius and may be used to evolve the profile over a long time scale, using a diffusion equation that is both nonlinear and non-local. This equation, containing an additional smoothing parameter, is simulated starting with a Gaussian vortex. Fine scale steps in the vorticity profile develop at the periphery of the vortex and these form a vorticity staircase. The effective diffusivity is high in the steps where the vorticity gradient is low: between the steps are barriers characterized by low effective diffusivity and high vorticity gradient. The steps then merge before the vorticity is finally swept out and this leaves a vortex with a compact core and a sharp edge. There is also an increase in the effective diffusion within an encircling surf zone.

In order to understand the properties of the evolution of the Gaussian vortex, an asymptotic model first proposed by Balmforth, Llewellyn Smith & Young (J. Fluid Mech., vol. 426, 2001, p. 95) is employed. The model is based on a vorticity distribution that consists of a compact vortex core surrounded by a skirt of relatively weak vorticity. Again simulations show the formation of fine scale vorticity steps within the skirt, followed by merger. The diffusion equation we develop has a tendency to generate vorticity steps on arbitrarily fine scales; these are limited in our numerical simulations by smoothing the effective diffusivity over small spatial scales.
Transhydrogenase and the anaerobic mitochondrial metabolism of adultHymenolepis diminuta
Authors: FIORAVANTI C. F. , VANDOCK K. P.
Published: September 2009

The adult cestode,Hymenolepis diminuta, is essentially anaerobic energetically. Carbohydrate dissimilation results in acetate, lactate and succinate accumulation with succinate being the major end product. Succinate accumulation results from the anaerobic, mitochondrial, ‘malic’ enzyme-dependent utilization of malate coupled to ATP generation via the electron transport-linked fumarate reductase. A lesser peroxide-forming oxidase is apparent, however, fumarate reduction to succinate predominates even in air. TheH. diminutamatrix-localized ‘malic’ enzyme is NADP-specific whereas the inner membrane (IM)-associated electron transport system prefers NADH. This dilemma is circumvented by the mitochondrial, IM-associated NADPH→NAD+transhydrogenase in catalyzing hydride ion transfer from NADPH to NAD+on the IM matrix surface. Hydride transfer is reversible and phospholipid-dependent. NADP+reduction occurs as a non energy-linked and energy-linked reaction with the latter requiring electron transport NADH utilization or ATP hydrolysis. With NAD+reduction, the cestode transhydrogenase also engages in concomitant proton translocation from the mitochondrial matrix to the intermembrane space and supports net ATP generation. Thus, the cestode NADPH→NAD+system can serve not only as a metabolic connector, but an additional anaerobic phosphorylation site. Although its function(s) is unknown, a separate IM-associated NADH→ NAD+transhydrogenation, catalyzed by the lipoamide and NADH dehydrogenases, is noted.
Evidence for high levels of vertical transmission in Toxoplasma gondii
Authors: HIDE G. , MORLEY E. K. , HUGHES J. M. , GERWASH O. , ELMAHAISHI M. S. , ELMAHAISHI K. H. , THOMASSON D. , WRIGHT E. A. , WILLIAMS R. H. , MURPHY R. G. , SMITH J. E.
Published: September 2009

Toxoplasma gondii is a highly ubiquitous and prevalent parasite. Despite the cat being the only definitive host, it is found in almost all geographical areas and warm blooded animals. Three routes of transmission are recognised: ingestion of oocysts shed by the cat, carnivory and congenital transmission. In natural populations, it is difficult to establish the relative importance of these routes. This paper reviews recent work in our laboratory which suggests that congenital transmission may be much more important than previously thought. Using PCR detection of the parasite, studies in sheep show that congenital transmission may occur in as many as 66% of pregnancies. Furthermore, in families of sheep on the same farm, exposed to the same sources of oocysts, significant divergent prevalences of Toxoplasma infection and abortion are found between different families. The data suggest that breeding from infected ewes increases the risk of subsequent abortion and infection in lambs. Congenital transmission rates in a natural population of mice were found to be 75%. Interestingly, congenital transmission rates in humans were measured at 19·8%. The results presented in these studies differ from those of other published studies and suggest that vertical transmission may be much more important than previously thought.
Characterization of spliced leader genes of Trypanosoma (Megatrypanum) theileri: phylogeographical analysis of Brazilian isolates from cattle supports spatial clustering of genotypes and parity with ribosomal markers
Authors: RODRIGUES A. C. , GARCIA H. A. , BATISTA J. S. , MINERVINO A. H. H. , GÓES-CAVALCANTE G. , MAIA DA SILVA F. , FERREIRA R. C. , CAMPANER M. , PAIVA F. , TEIXEIRA M. M. G.
Published: September 2009

Trypanosoma (Megatrypanum) theileri from cattle and trypanosomes of other artiodactyls form a clade of closely related species in analyses using ribosomal sequences. Analysis of polymorphic sequences of a larger number of trypanosomes from broader geographical origins is required to evaluate the clustering of isolates as suggested by previous studies. Here, we determined the sequences of the spliced leader (SL) genes of 21 isolates from cattle and 2 from water buffalo from distant regions of Brazil. Analysis of SL gene repeats revealed that the 5S rRNA gene is inserted within the intergenic region. Phylogeographical patterns inferred using SL sequences showed at least 5 major genotypes of T. theileri distributed in 2 strongly divergent lineages. Lineage TthI comprises genotypes IA and IB from buffalo and cattle, respectively, from the Southeast and Central regions, whereas genotype IC is restricted to cattle from the Southern region. Lineage TthII includes cattle genotypes IIA, which is restricted to the North and Northeast, and IIB, found in the Centre, West, North and Northeast. PCR-RFLP of SL genes revealed valuable markers for genotyping T. theileri. The results of this study emphasize the genetic complexity and corroborate the geographical structuring of T. theileri genotypes found in cattle.
Moving towards an integrated approach to molecular detection and identification ofToxoplasma gondii
Authors: SU C. , SHWAB E. K. , ZHOU P. , ZHU X. Q. , DUBEY J. P.
Published: September 2009

The development of simple, sensitive and rapid methods for the detection and identification ofToxoplasma gondiiis important for the diagnosis and epidemiological studies of the zoonotic disease toxoplasmosis. In the past 2 decades, molecular methods based on a variety of genetic markers have been developed, each with its advantages and limitations. The application of these methods has generated invaluable information to enhance our understanding of the epidemiology, population genetics and phylogeny ofT. gondii. However, since most studies focused solely on the detection but not genetic characterization ofT. gondii, the information obtained was limited. In this review, we discuss some widely used molecular methods and propose an integrated approach for the detection and identification ofT. gondii, in order to generate maximum information for epidemiological, population and phylogenetic studies of this key pathogen.
Biological invasion and parasitism: invaders do not suffer from physiological alterations of the acanthocephalanPomphorhynchus laevis
Authors: CORNET S. , SORCI G. , MORET Y.
Published: September 2009

Biological invasions expose parasites to new invasive hosts in addition to their local hosts. However, local parasites are often less successful in infecting and exploiting their new hosts. This may have major consequences for the competitive ability of hosts, and finally on the fate of the parasite-host community. In Burgundy (Eastern France), the acanthocephalan parasite,Pomphorhynchus laevis, infects 2 amphipod species living in sympatry: the nativeGammarus pulexand the invasiveGammarus roeseli. WhileP. laevisaffects the behaviour and the immunity ofG. pulex,G. roeseliseems unaffected by the infection. In this study, we examined in detail the ability of the parasite to affect the immune system and resource storage of both gammarid species. We found that the infection was associated with a general decrease of the prophenoloxidase activity, haemocyte density, resistance to an artificial bacterial infection and level of sugar reserves inG. pulex, but not inG. roeseli. These results demonstrate a differential ability ofP. laevisto exploit its local and its invasive gammarid hosts. Potential mechanisms of these differential physiological alterations and their potential consequences on the coexistence of both gammarid species in sympatry are discussed.
Occurrence and molecular characterization ofCryptosporidiumspp. genotypes in European hedgehogs (Erinaceus europaeusL.) in Germany
Authors: DYACHENKO V. , KUHNERT Y. , SCHMAESCHKE R. , ETZOLD M. , PANTCHEV N. , DAUGSCHIES A.
Published: September 2009

Juvenile hedgehogs having insufficient body weight are often brought for overwintering to hedgehog rehabilitation centres. Faecal samples of juvenile hedgehogs and overwintering hedgehogs (n=188) collected prior to releasing them back into the wilderness were examined for the presence ofCryptosporidiumcoproantigen and oocysts. Altogether 56 (29·8%) submitted samples were positive for coproantigen. Forty-five (39·5%,n=114) of the positive samples originated from newly rescued hedgehogs, while 11 (14·8%,n=74) positive samples were from animals that spent several months at the station. Fifteen samples subjected to PCR-RFLP analysis on the partial 18S rRNA locus suggested the presence ofC. parvum. Multilocus sequence typing on partial 60 kDa glycoprotein gene, 18S rRNA, actin gene, 70 kDa heat shock protein gene sequences revealed 3 different subtype families: IIa, IIc and a new, proposed as VIIa subtype family.Cryptosporidiumsp. genotype belonging to VIIa subtype family is closely related toC. parvumbut is genetically distinct being probably a hedgehog-specificCryptosporidiumsp. genotype with unknown zoonotical potential. Hedgehogs excretingCryptosporidiumoocysts represent a potential source for human infections, but also an anthroponotic nature of the IIc subtype family should be reviewed.
Infection success of different trematode genotypes in two alternative intermediate hosts: evidence for intraspecific specialization?
Authors: LEUNG T. L. F. , POULIN R.
Published: September 2009

The evolution of host specificity and the potential trade-off between being a generalist and a specialist are central issues in the evolutionary ecology of parasites. Different species of parasites or even different populations of the same species often show different degrees of host specificity. However, less is known about intraspecific variation in host specificity within a population. We investigated intraspecific variation by experimentally exposing cercariae from different clones of the trematodeCurtuteria australisto two species of second intermediate hosts, the New Zealand cockleAustrovenus stutchburyiand the wedge shellMacomona liliana. We found an overall difference in infection success between the two bivalve species, withA. stutchburyibeing the more heavily infected host. However, the cercariae showed a consistent preference for encysting at the tip of the bivalve's foot, regardless of host species. Importantly, there were no significant differences among parasite clones in either relative infection success in the two hosts or preference for the host foot tip. This lack of intraspecific variation may be due to the life-history traits of both parasite and hosts in our system, which may limit opportunities for variation in performance and exploitation strategies in different hosts to evolve within the population.