bluuebunny/crossref_metadata_2025 huggingface dataset:
Immobilization of Phospholipase C for the Production of Ceramide from Sphingomyelin Hydrolysis
Authors: Zhang Long , Hellgren Lars I. , Xu Xuebing
Published: January 2007

The immobilization of Clostridium perfringens phospholipase C was studied for the first time and the catalytic properties of the immobilized enzyme were investigated for the hydrolysis of sphingomyelin to produce ceramide. Ceramide is of great commercial value in the cosmetic and pharmaceutical industries for use in, for example, hair and skin care products, owing to its major role in maintaining the water‐retaining properties of the epidermis. The feasibility of enzymatic production of ceramide through hydrolysis of sphingomyelin has previously been proven. In order to improve the reusability of the enzyme, the present study focused on the immobilization of phospholipase C in the production of ceramide from sphingomyelin. By screening nine different carriers, we found that the enzyme immobilized on Lewatit had the highest catalytic activity towards sphingomyelin hydrolysis. Prewetting Lewatit with ethanol led to higher enzyme fixation on the carrier, but the activity of the enzyme was decreased. Increasing the initial enzyme concentration resulted in more enzyme adsorption on the carrier, where the specific activity was increased. Through optimization of the reaction using the immobilized enzyme, the optimal temperature was around 46 °C and the optimal water volume was 3.5%. The reaction had little dependence on pH. After seven recycles, immobilized enzyme retained around 70% of the initial activity. Immobilized enzyme was deactivated irregularly when stored at room temperature, but followed first‐order deactivation when stored at 40 °C.
Timing irrigation to suit citrus phenology: a means of reducing water use without compromising fruit yield and quality?
Authors: Hutton R. J. , Landsberg J. J. , Sutton B. G.
Published: January 2007

This paper addresses the question of whether a citrus crop has the same need for water at all stages of development or whether it is possible to withhold water at times when the crop is less sensitive to water stress, thus, reducing total water use and improving water use efficiency while still maintaining yield. To answer this question water applied by irrigation was reduced by up to 33% relative to standard full irrigation by extending the intervals between applications from 3 to 17 days during fruit growth stages II and III in the annual growth cycle. As expected, the longer intervals resulted in greater depletion in soil moisture and significant water stress developed as soil water deficits approached the lower limits of plant available water. Stressed trees exhibited mean pre-dawn water potential (ψl) values of –0.93 MPa and midday ψl values decreased to between –2.0 and –2.5 MPa. Periodic soil water deficits in late summer and autumn reduced shoot growth, but fruit yield was unaffected, and there was no evidence of reduced canopy size. Water use efficiency (mass of fruit produced per unit water applied) improved, but fruit growth was extremely sensitive to moisture stress and extended irrigation intervals in summer and autumn reduced fruit size. Fruit juice quality was also affected, as there was an increase in both total soluble solids and juice acidity, but the practical consequences of these were limited because there were only small changes to the sugar : acid ratios. This work has demonstrated that deficient irrigation during summer can be used to manipulate growth and reduce water use, but at the risk of a marginal reduction in fruit size.
Essential oil vapours control some common postharvest fungal pathogens
Authors: Szczerbanik M. , Jobling J. , Morris S. , Holford P.
Published: January 2007

Diseases caused by fungal pathogens cause substantial postharvest losses to most perishable food crops. Fungal diseases are currently controlled with fungicides; however, reliance on this single control strategy leads to problems such as environmental damage and fungal resistance to fungicides. There is increasing pressure from consumers to find more natural methods of disease control. A possible alternative to fungicides may be essential oils, which have been shown to inhibit the growth of several fungi and are seen as natural compounds. The present study examined the effect of the vapour phase of spearmint, tea tree, pine and cinnamon oils and an antifungal blend on the growth of eight common postharvest fungal pathogens growing in vitro. It was found that the antifungal, spearmint and tea tree oils controlled the growth of Botrytis cinerea, Fusarium solani, Colletotrichum sp., Geotrichum candidum, Rhizopus oryzae, Aspergillus niger and Cladosporium cladosporiodes more effectively than pine or cinnamon oil but were less effective against Penicillium digitatum. Antifungal, spearmint and tea tree oils appeared to reduce sporulation in P. digitatum, A. niger and R. oryzae and inhibited spore germination by A. niger. This work shows that the antifungal, spearmint and tea tree oil vapours may provide an alternative means of controlling postharvest pathogens. All of the oils had a fungistatic mode of action and their use would require the development of commercial treatment methods applicable throughout the postharvest handling chain.
Mycorrhizal colonisation of three hybrid papayas (Carica papaya) under mulched and bare ground conditions
Authors: Walsh K. B. , Ragupathy S.
Published: January 2007

The use of straw mulching has been demonstrated to decrease soil loss and to improve soil moisture and soil organic matter content in conjunction with papaya (Carica papaya) cultivation. Mulching may also benefit soil biota. In this study, mulching was demonstrated to significantly (P < 0.05) improve arbuscular mycorrhizal fungal colonisation of papaya roots (by a factor of 2.4), but decreased spore density and species diversity (by a factor of 1.5), compared with cultivation in bare ground. The genera Glomus, Acaulospora, Gigaspora and Sclerocystis dominated in both mulched and bare ground systems. The increased mycorrhizal activity in the mulched treatments was matched by an increase in leaf phosphorus in 1995 but not in 1997.
Spatial targeting of type II protein kinase A to filopodia mediates the regulation of growth cone guidance by cAMP
Authors: Han Jianzhong , Han Liang , Tiwari Priyanka , Wen Zhexing , Zheng James Q.
Published: January 2007

The second messenger cyclic adenosine monophosphate (cAMP) plays a pivotal role in axonal growth and guidance, but its downstream mechanisms remain elusive. In this study, we report that type II protein kinase A (PKA) is highly enriched in growth cone filopodia, and this spatial localization enables the coupling of cAMP signaling to its specific effectors to regulate guidance responses. Disrupting the localization of PKA to filopodia impairs cAMP-mediated growth cone attraction and prevents the switching of repulsive responses to attraction by elevated cAMP. Our data further show that PKA targets protein phosphatase-1 (PP1) through the phosphorylation of a regulatory protein inhibitor-1 (I-1) to promote growth cone attraction. Finally, we find that I-1 and PP1 mediate growth cone repulsion induced by myelin-associated glycoprotein. These findings demonstrate that the spatial localization of type II PKA to growth cone filopodia plays an important role in the regulation of growth cone motility and guidance by cAMP.
Cytomegalovirus infection in renal transplant recipients is associated with impaired survival irrespective of expected mortality risk
Authors: Sagedal Solbjørg , Rollag Halvor , Hartmann Anders
Published: January 2007

Abstract: Cytomegalovirus (CMV) infection and CMV disease are associated with increased mortality post‐transplantation. We have thus retrospectively examined whether this association is found both in patients with high and low mortality risk. Between 1994 and 1997, 471 kidney transplant recipients were monitored once weekly for CMV pp65 antigenemia and CMV disease the first 100 d after tx and followed prospectively for median 66.6 months. Patients with nephrosclerosis, diabetic nephropathy and amyloidosis were selected as high mortality risk groups (HRG). Overall and cardiovascular mortality beyond 100 d in the low‐risk group (n = 372) was 14% and 3.5%, and in the HRG (n = 99) 31% and 16%, respectively. The effects of CMV infection and disease, recipient age and gender, panel‐reactive cytotoxic antibodies, acute rejection, HRG, and graft loss in the whole study period were tested on overall mortality beyond 100 d in multiple analysis. HRG was independently associated with overall mortality, RR = 2.03, and still both CMV infection and disease were significant risk factors for mortality, independent of HRG. The same analysis was repeated for HRG (n = 99). Even in this small group CMV disease was independently associated with overall mortality. These data indicate that CMV increase mortality independently both in patients with otherwise high‐ or low‐risk for long‐term mortality.
Privilege, Empowerment, and Nonviolent Intervention
Authors: Boothe Ivan , Smithey Lee A.
Published: January 2007

When the important work of third‐party nonviolent intervention is undertaken by people with relative privilege, it runs the risk of hindering the empowerment of the local movements they aim to assist by replicating racist or classist dynamics in the struggle itself. By relying on the status attached to the economic, cultural, and military dominance of the Global North, nonviolent intervention organizations can facilitate a relationship of dependency that offers short‐term strategic advantages but that in itself is less likely to promote the nonviolent empowerment of local movements. Sensitivity training within intervention organizations may help activists strategize in ways that avoid some of the pitfalls of operating from positions of privilege.
Risk of amputation in patients with diabetic foot ulcers: a claims‐based study
Authors: Markowitz Jeffrey S. , Gutterman Elane M. , Magee Glenn , Margolis David J.
Published: January 2007

The objective of this study was to undertake a retrospective analysis of claims data of diabetic foot ulcer (DFU) patients to determine the rates of amputation and identify the risk and protective factors. Rates of amputation were calculated in patients diagnosed with DFU in the MEDSTAT Marketscan database between January 2000 and December 2002, who had prediagnosis coverage of 90 days. A nested case–control study was conducted using a 1 : 10 ratio of amputee cases to randomly selected nonamputee controls matched on follow‐up days. The association of co‐morbid conditions, demographic factors, and severity (5+ outpatient claims for DFU) on amputation was estimated by adjusted odds ratios (AOR) with 95% confidence intervals (CIs). The 5911 eligible patients yielded an incidence density rate of 2.30 amputations per 100 person years (95% CI = 1.91, 2.77). The 116 cases and 1153 controls averaged 307.3 and 308.5 observation days, respectively. Amputation was significantly increased by male gender (AOR 1.98), Charlson co‐morbidity scores of 4–5 and 6+ (AOR = 2.89 and 5.36, respectively), renal disease (AOR = 2.11), peripheral vascular disease (AOR = 2.67), and 5+ outpatient DFU services (AOR = 2.17). Practitioners may consider more aggressive care and earlier referral to specialists for DFU patients who fit risk profiles for amputation, which include peripheral vascular disease, multiple co‐morbid conditions, and repeated outpatient DFU services.
Perflubron emulsion increases subcutaneous tissue oxygen tension in rats
Authors: Rosen Noah A. , Hopf Harriet W. , Hunt Thomas K.
Published: January 2007

Oxygen plays a central role in wound healing. The hypothesis of this study was that the administration of a perfluorocarbon emulsion, which dissolves oxygen will increase subcutaneous tissue oxygen tension (PsqO2) in normovolemic and hemorrhaged animals. In the first set of experiments, PsqO2 was measured with a polarographic oxygen electrode along the dorsum of normovolemic‐anesthetized rats (n=20) breathing supplemental oxygen. After baseline equilibration of tissue oxygen tension, perflubron emulsion (n=12) or saline control (n=8) was administered. Perflubron administration increased PsqO2 by 32.0 ± 7.2 mmHg, whereas saline administration had no effect (−1.0 ± 6.6 mmHg). In a second set of experiments, PsqO2 (n=12) was measured in rats breathing 100 percent oxygen after being bled 20 percent of their blood volume. Creating hypovolemic rats allowed for the study of the effect of perflubron emulsion administration on subcutaneous oxygen tension in tissues with compromised blood flow. Perflubron emulsion was only effective at increasing oxygen tension in tissues with oxygen extractions less then 2.0 vol%. These findings agree with those results analytically predicted based on the oxygen solubility of the perflubron emulsion.
Sulodexide: A Renewed Interest in This Glycosaminoglycan
Authors: Lauver D. Adam , Lucchesi Benedict R.
Published: January 2007

Glycosaminoglycans (GAGs) are the most abundant group of heteropolysaccharides found in the body. These long unbranched molecules contain a repeating disaccharide unit. GAGs are located primarily in the extracellular matrix or on the surface of cells. These molecules serve as lubricants in the joints while at the same time providing structural rigidity to cells. Sulodexide is a highly purified glycosaminoglycan composed of a fast mobility heparin fraction as well as dermatan sulfate. Sulodexide differs from other glycosaminoglycans, like heparin, by having a longer half‐life and a reduced effect on systemic clotting and bleeding. In addition, sulodexide demonstrates a lipolytic activity that is increased in comparison to heparin. Oral administration of sulodexide results in the release of tissue plasminogen activator and an increase in fibrinolytic activities. An increasing body of research has demonstrated the safety and efficacy of sulodexide in a wide range of vascular pathologies.
Collective Cognition: When Entrepreneurial Teams, Not Individuals, Make Decisions
Authors: West G. Page
Published: January 2007

New venture success often depends on how the founding team collectively understands its world, estimates effects of possible actions, makes decisions, and allocates appropriate resources. Drawing on recent work in managerial cognition and entrepreneurship, this article argues for the importance of examining cognition at the team level. New venture strategy is used as a springboard to discuss collective cognition, although other important critical decision domains in new ventures may also be used to illustrate the arguments. In this and other such decision domains, collective cognition mediates between individual cognitions and firm actions and performance. A method for assessing entrepreneurial top management team cognition is developed and then tested in an exploratory study of technology–based new ventures. Two structural characteristics of collective cognition (differentiation and integration) are strongly related to firm performance, suggesting interesting opportunities for future entrepreneurship research in cognition.
An Airborne and Wind Tunnel Evaluation of a Wind Turbulence Measurement System for Aircraft-Based Flux Measurements*
Authors: Garman K. E. , Hill K. A. , Wyss P. , Carlsen M. , Zimmerman J. R. , Stirm B. H. , Carney T. Q. , Santini R. , Shepson P. B.
Published: January 2007

Although the ability to measure vertical eddy fluxes of gases from aircraft platforms represents an important capability to obtain spatially resolved data, accurate and reliable determination of the turbulent vertical velocity presents a great challenge. A nine-hole hemispherical probe known as the “Best Air Turbulence Probe” (often abbreviated as the “BAT Probe”) is frequently used in aircraft-based flux studies to sense the airflow angles and velocity relative to the aircraft. Instruments such as inertial navigation and global positioning systems allow the measured airflow to be converted into the three-dimensional wind velocity relative to the earth’s surface by taking into account the aircraft’s velocity and orientation. Calibration of the aircraft system has previously been performed primarily through in-flight experiments, where calibration coefficients were determined by performing various flight maneuvers. However, a rigorous test of the BAT Probe in a wind tunnel has not been previously undertaken.

The authors summarize the results of a complement of low-speed wind tunnel tests and in-flight calibrations for the aircraft–BAT Probe combination. Two key factors are addressed in this paper: The first is the correction of systematic error arising from airflow measurements with a noncalibrated BAT Probe. The second is the instrumental precision in measuring the vertical component of wind from the integrated aircraft-based wind measurement system. The wind tunnel calibration allows one to ascertain the extent to which the BAT Probe airflow measurements depart from a commonly used theoretical potential flow model and to correct for systematic errors that would be present if only the potential flow model were used. The precision in the determined vertical winds was estimated by propagating the precision of the BAT Probe data (determined from the wind tunnel study) and the inertial measurement precision (determined from in-flight tests). The precision of the vertical wind measurement for spatial scales larger than approximately 2 m is independent of aircraft flight speed over the range of airspeeds studied, and the 1σ precision is approximately 0.03 m s−1.
Risk factors and myocardial infarction in patients with obstructive sleep apnea: impact of β2-adrenergic receptor polymorphisms
Authors: Bartels Nina K , Börgel Jan , Wieczorek Stefan , Büchner Nikolaus , Hanefeld Christoph , Bulut Daniel , Mügge Andreas , Rump Lars C , Sanner Bernd M , Epplen Jörg T
Published: January 2007

Background

The increased sympathetic nervous activity in patients with obstructive sleep apnea (OSA) is largely responsible for the high prevalence of arterial hypertension, and it is suggested to adversely affect triglyceride and high-density lipoprotein (HDL) cholesterol levels in these patients. The functionally relevant polymorphisms of the β2-adrenergic receptor (Arg-47Cys/Arg16Gly and Gln27Glu) have been shown to exert modifying effects on these risk factors in previous studies, but results are inconsistent.

Methods

We investigated a group of 429 patients (55 ± 10.7 years; 361 men, 68 women) with moderate to severe obstructive sleep apnea (apnea/hypopnea index (AHI) 29.1 ± 23.1/h) and, on average, a high cardiovascular risk profile (body mass index 31.1 ± 5.6, with hypertension in 60.1%, dyslipidemia in 49.2%, and diabetes in 17.2% of patients). We typed the β2-adrenergic receptor polymorphisms and investigated the five most frequent haplotypes for their modifying effects on OSA-induced changes in blood pressure, heart rate, and lipid levels. The prevalence of cardiovascular risk factors and coronary heart disease (n = 55, 12.8%) and survived myocardial infarction (n = 27, 6.3%) were compared between the genotypes and haplotypes.

Results

Multivariate linear/logistic regressions revealed a significant and independent (from BMI, age, sex, presence of diabetes, use of antidiabetic, lipid-lowering, and antihypertensive medication) influence of AHI on daytime systolic and diastolic blood pressure, heart rate, prevalence of hypertension, and triglyceride and HDL levels. The β2-adrenergic receptor genotypes and haplotypes showed no modifying effects on these relationships or on the prevalence of dyslipidemia, diabetes, and coronary heart disease, yet, for all three polymorphisms, heterozygous carriers had a significantly lower relative risk for myocardial infarction (Arg-47Cys: n = 195, odds ratio (OR) = 0.32, P = 0.012; Arg16Gly: n = 197, OR = 0.39, P = 0.031; Gln27Glu: OR = 0.37, P = 0.023). Carriers of the most frequent haplotype (n = 113) (haplotype 1; heterozygous for all three polymorphisms) showed a five-fold lower prevalence of survived myocardial infarction (OR = 0.21, P = 0.023).

Conclusion

Our study showed no significant modifying effect of the functionally relevant β2-adrenergic receptor polymorphisms on OSA-induced blood pressure, heart rate, or lipid changes. Nevertheless, heterozygosity of these polymorphisms is associated with a lower prevalence of survived myocardial infarction in this group with, on average, a high cardiovascular risk profile.
Analytical modeling of reservoir effect on electromigration in Cu interconnects
Authors: Gan Zhenghao , Gusak A.M. , Shao W. , Chen Zhong , Mhaisalkar S.G. , Zaporozhets T. , Tu K.N.
Published: January 2007

Electromigration (EM) in Cu dual-damascene interconnects with extensions (also described as overhangs or reservoirs) ranging from 0 to 120 nm in the upper metal (M2) was investigated by an analytical model considering the work of electron wind and surface/interface energy. It was found that there exists a critical extension length beyond which increasing extension lengths ceases to prolong electromigration lifetimes. The critical extension length is a function of void size and electrical field gradient. The analytical model agrees very well with existing experimental results. Some design guidelines for electromigration-resistant circuits could be generated by the model.
Coarsening kinetics of intermetallic precipitates in Ni75AlxV25−x alloys
Authors: Li Y.S. , Chen Z. , Lu Y.L. , Wang Y.X.
Published: January 2007

The precipitation kinetics of growth and coarsening of γ′(Ni3Al) and θ (Ni3V) in Ni75AlxV25−x alloys were investigated by microscopic phase-field simulation incorporated with elastic interactions. For the elastic interactions, γ′ aligned along the 〈001〉 direction and θ aligned along the [100] direction, which resulted in plate shape. For the lower (x < 4, at.%) and higher (x > 6) content regions, the growth of first precipitates was dominant at the initial stage and then coarsening was dominant, but the growth and coarsening proceeded simultaneously for the second precipitates. The growth and coarsening of γ′ and θ were dominant, respectively, at the initial and late stages for middle content regions. In addition, dynamic scaling was analyzed in the two-phase systems. It was shown that the dynamic scaling regimes were attained simultaneously at late-stage coarsening for γ′ and θ, despite the different precipitation order.
A topological approach to design Ni-based bulk metallic glasses with high corrosion resistance
Authors: Wang A.P. , Wang J.Q.
Published: January 2007

The structural model for metallic glasses and the topological instability criterion for multicomponent alloy systems have been combined to formulate a design protocol for bulk metallic glasses (BMGs). New Ni-Nb-Zr bulk metallic glasses with high corrosion resistance have been discovered. The experimental results in literature also support the use of this approach as a practically efficient method to select bulk metallic glass-forming compositions.
Expression of cyclooxygenase-1 and -2 in naturally occurring squamous cell carcinomas in horses
Authors: Elce Yvonne A. , Orsini James A. , Blikslager Anthony T.
Published: January 2007

Objective—To assess expression of cyclooxygenase (COX)-1 and -2 in naturally occurring squamous cell carcinomas (SCCs) and the analogous normal tissues in horses.

Sample Population—Tissue samples collected from 3 conjunctival, 2 vulvar, 4 preputial, and 5 penile SCCs during surgical excision in 14 horses and from corresponding body regions (conjunctiva [n = 5 horses], vulva [2], prepuce [3], and penis [3]) in 5 horses euthanized for reasons unrelated to neoplasia.

Procedures—Tissue samples were snap frozen in liquid nitrogen and stored at −80°C until analysis. Protein was extracted from the frozen tissues, and western blot analyses were performed. Nonneoplastic and abnormal tissues from each body region were run on the same blot, and blots were run in triplicate. Molecular-weight markers and COX-1 and 2 ovine standards (positive control samples) were run concurrently on the gels; negative control samples were not used.

Results—All tissues, including the nonneoplastic and SCC tissues, expressed both COX-1 and -2 proteins.

Conclusions and Clinical Relevance—Results indicated that the expression of COX proteins in both nonneoplastic and SCC-affected tissues in horses is markedly different from that in other species. The reason for the potential benefit of COX-2 inhibitors in horses and other species is unknown. Further research needs to be performed to evaluate the efficacy of COX-2 inhibitors as cancer treatments in horses. Investigation of the mechanisms of tumor development in horses should be performed to increase understanding of this disease and ascertain how the mechanisms differ from those in other animals.
Neutrophil myeloperoxidase measurements in plasma, laminar tissue, and skin of horses given black walnut extract
Authors: Riggs Laura M. , Franck Thierry , Moore James N. , Krunkosky Thomas M. , Hurley David J. , Peroni John F. , de la Rebière Geoffroy , Serteyn Didier A.
Published: January 2007

Objective—To compare measurements of myeloperoxidase (MPO) in plasma, laminar tissues, and skin obtained from control horses and horses given black walnut heartwood extract (BWHE).

Animals—22 healthy 5- to 15-year-old horses.

Procedures—Horses were randomly assigned to 4 groups as follows: a control group given water (n = 5) and 3 experimental groups given BWHE (17) via nasogastric intubation. Experimental groups consisted of 5, 6, and 6 horses that received BWHE and were euthanatized at 1.5, 3, and 12 hours after intubation, respectively. Control horses were euthanatized at 12 hours after intubation. Plasma samples were obtained hourly for all horses. Laminar tissue and skin from the middle region of the neck were harvested at the time of euthanasia. Plasma and tissue MPO concentrations were determined via an ELISA; tissue MPO activity was measured by use of specific immunologic extraction followed by enzymatic detection.

Results—Tissues and plasma of horses receiving BWHE contained significantly higher concentrations of MPO beginning at hour 3. Laminar tissue and skin from horses in experimental groups contained significantly higher MPO activity than tissues from control horses. Concentrations and activities of MPO in skin and laminar tissues were similar over time.

Conclusions and Clinical Relevance—In horses, BWHE administration causes increases in MPO concentration and activity in laminar tissue and skin and the time of increased MPO concentration correlates with emigration of WBCs from the vasculature. These findings support the hypothesis that activation of peripheral WBCs is an early step in the pathogenesis of acute laminitis.
Heuristic rescheduling of crude oil operations to manage abnormal supply chain events
Authors: Adhitya Arief , Srinivasan Rajagopalan , Karimi I. A.
Published: January 2007

Globalization and the resultant complexity of today's supply chains require that enterprises be agile and proactive. This communication looks at a refinery supply chain where disruptions such as crude arrival delay could make the current schedule infeasible and necessitate rescheduling of operations. Existing approaches for generating (near) optimal schedules for a real‐world refinery typically require significantly large amounts of time. This is undesirable when rectification decisions need to be made in a short time. Further, when the problem data given to the existing scheduling approaches are changed, as is the case during a disruption, the optimizers follow different solution paths and result in substantially different schedules. A heuristic rescheduling strategy is proposed that overcomes both these shortcomings. The key insight exploited here is that any schedule can be broken into operation blocks. Rescheduling is performed by modifying these blocks in the original schedule using simple heuristics to generate a new schedule that is feasible for the new problem data. Our strategy avoids major operational changes by preserving—as far as possible—the blocks in the original schedule. The major advantages of the proposed method are its real‐time computational performance and the minimal changes to the operations as compared to total rescheduling. Further, the proposed strategy can also identify many feasible schedules and allow refinery personnel to select one by considering other factors that cannot be adequately modeled in a scheduler. Our method is illustrated using five types of disruptions occurring in a refinery. The various factors that affect the robustness of a supply chain in the face of disruptions are also discussed. © 2007 American Institute of Chemical Engineers AIChE J, 2007.
Axisymmetric field generation within an ambient axial field
Authors: Darah A. A. , Sarson G. R.
Published: January 2007

The generation of magnetic field in a homogeneous, electrically conducting fluid – as required for the dynamo generation of the fields of many astrophysical bodies – is normally a threshold process; the dynamo mechanism, applicable to such bodies in unmagnetised environments, requires motions of sufficient strength to overcome the innate magnetic diffusion. In the presence of an ambient field, however, the critical nature of the field generation process is relaxed. Motions can distort and amplify the ambient field for all amplitudes of flow. For motions with appropriate geometries, an internal ‘dynamo‐like’ field of appreciable strength can be generated, even for relatively weak flows. At least a minority of planets, moons and other bodies exist within significant external astrophysical fields. For these bodies, the ambient field problem is more relevant than the classical dynamo problem, yet it remains relatively little studied. In this paper we consider the effect of an axial ambient field on a spherical mean‐field α 2ω dynamo model, through nonlinear calculations with α ‐quenching feedback. Ambient fields of varying strengths, and both stationary and oscillatory in time, are imposed. Particular focus is placed on the effects of these fields on the equatorial symmetry and the time dependence of the preferred solutions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Contribution to the study of composite spectra: XI. Orbital elements of some faint systems
Authors: Carquillat J.‐M. , Prieur J.‐L.
Published: January 2007

We present the results of a radial‐velocity study of nine new faint SB1 spectroscopic binaries with composite spectra: HD 137975‐6, 177984, HDE 226489, 231613‐4, 255387‐8, 256138‐9, 264997‐8, 276787 and 293041‐2. The observations were made at Haute‐Provence and Cambridge observatories with CORAVEL instruments between 1982 and 2006. From the radial‐velocity measurements of the cool components, we derive the orbital elements of those spectroscopic binaries for the first time. Using all the available data, we propose a model for each system that describes the nature of the individual components, with an estimation of the angular separation and orbital inclination. Finally we discuss the rotation–revolution synchronism of the cool components. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discovery of magnetic fields in three He variable Bp stars with He and Si spots
Authors: Briquet M. , Hubrig S. , Schöller M. , De Cat P.
Published: January 2007

It is essential for the understanding of stellar structure models of high mass stars to explain why constant stars, nonpulsating chemically peculiar hot Bp stars and pulsating stars co‐exist in the slowly pulsating B stars and β Cephei instability strips. We have conducted a search for magnetic fields in the four Bp stars HD55522, HD105382, HD131120, and HD138769 which previously have been wrongly identified as slowly pulsating B stars. A recent study of these stars using the Doppler Imaging technique revealed that the elements He and Si are inhomogeneously distributed on the stellar surface, causing the periodic variability. Using FORS 1 in spectropolarimetric mode at the VLT, we have acquired circular polarisation spectra to test the presence of a magnetic field in these stars. A variable magnetic field is clearly detected in HD55522 and HD105382, but no evidence for the existence of a magnetic field was found in HD131120. The presence of a magnetic field in HD138769 is suggested by one measurement at 3σ level. We discuss the occurrence of magnetic B stars among the confirmed pulsating B stars and find strong magnetic fields of order kG and oscillations to be mutually exclusive. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydrogen‐Bonded Dendronized Polymers and Their Self‐Assembly in Solution
Authors: Xie Dang , Jiang Ming , Zhang Guangzhao , Chen Daoyong
Published: January 2007

Frechet‐type benzyl ether dendrons of second and third generations with a carboxyl group (G2, G3) at the apex site could attach to poly(4‐vinylpyridine) (PVP), forming hydrogen‐bonded dendronized polymers (HB denpols) in their common solvent, chloroform. The HB denpols show unique self‐assembly behavior, forming vesicles in the common solvent under ultrasonic treatment. The structure and morphology of the vesicles were characterized by dynamic light scattering (DLS), static light scattering (SLS), SEM, TEM, and AFM. The size of the vesicles decreases and the thickness of the vascular membrane increases as the molar ratio of Gx/PVP increases. The hydrogen bonding, π–π aromatic stacking of the dendrons, and the considerable difference in architecture between the dendron Gx and PVP are the main factors facilitating the assembly of the HB denpols in the common solvent.
Modelling a sequencing batch reactor to treat the supernatant from anaerobic digestion of the organic fraction of municipal solid waste
Authors: Dosta Joan , Galí Alexandre , Macé Sandra , Mata‐Álvarez Joan
Published: January 2007

In this study, a lab‐scale sequencing batch reactor (SBR) has been tested to remove chemical oxygen demand (COD) and NH4+‐N from the supernatant of anaerobic digestion of the organic fraction of municipal solid waste. This supernatant was characterized by a high ammonium concentration (1.1 g NH4+‐N L−1) and an important content of slowly biodegradable and/or recalcitrant COD (4.8 g total COD L−1). Optimum SBR operating sequence was reached when working with 3 cycles per day, 30 °C, SRT 12 days and HRT 3 days. During the time sequence, two aerobic/anoxic steps were performed to avoid alkalinity restrictions. Oxygen supply and working pH range were controlled to promote the nitrification over nitrite. Under steady state conditions, COD and nitrogen removal efficiencies of more than 65% and 98%, respectively, were achieved. A closed intermittent‐flow respirometer was used to characterize and model the SBR performance. The activated sludge model ASM1 was modified to describe the biological nitrogen removal over nitrite, including the inhibition of nitrification by unionized ammonia and nitrous acid concentrations, the pH dependency of both autotrophic and heterotrophic biomass, pH calculation and the oxygen supply and stripping of CO2 and NH3. Once calibrated by respirometry, the proposed model showed very good agreement between experimental and simulated data. Copyright © 2007 Society of Chemical Industry
Rapid quantification of sucrose esters in oriental tobacco by liquid chromatography‐ion trap mass spectrometry
Authors: Ding Li , Xie Fuwei , Zhao Mingyue , Wang Sheng , Xie Jianping , Xu Guowang
Published: January 2007

A rapid and sensitive LC‐MS/MS method was developed for the quantitative determination of sucrose esters (SEs) in Oriental tobacco samples. The sample preparation involved a 10‐min sonication extraction procedure with acetone and five‐fold dilution of the extract with methanol. The experiment was carried out in positive ion mode by ESI IT mass spectrometer. Because of lack of authentic standards of SEs, sucrose octa‐acetate (internal standard, IS) was used as a surrogate to validate the proposed method. Matrix‐matched standard calibration was used for quantification of IS in the spiked samples. Under optimized MS/MS conditions, an LOQ of 3.9 μg/g was achieved for IS, with an LOD of about 1.2 μg/g. Recoveries for IS were 95–97%. Among 19 monitored SEs, the contents of 11 SEs had RSDs lower than 13.7%. The method, with very little sample handling and good sensitivity, was applied to the rapid quantification of SEs in four Oriental tobacco samples. It appears that the sum of contents of the five SEs with MW 650, 664, and 678 Da occupied approximately 80% of the total content of SEs.
Low‐cost data communication network for rural telecom network management
Authors: Jagadish C. , Jammula Vinod Kumar , Gonsalves Timothy A.
Published: January 2007

The backbone networking infrastructure of rural telecom networks is often costly and is of limited bandwidth. The availability of connectivity such as DSL or leased lines is scarce. In order to keep operational costs low, these rural telecom networks are often kept unmanned and are managed from a centralized network management station (NMS). This often requires a low‐cost, efficient and reliable data communication network (DCN) between the rural telecom equipment and the central NMS. The conventional DCN used for telecom management consists either of leased lines or Internet connectivity. These are often costly and not freely available in rural areas. We have developed a new DCN model, based on dial‐up, which is easily available. Using mathematical models and measurements we show that this DCN meets the QoS requirements of a telecom network at an affordable cost. We have implemented this DCN in corDECT networks. This is in use in India and Tunisia, and is under implementation in other similar countries. Copyright © 2007 John Wiley & Sons, Ltd.
Differential radioactive quantification of protein abundance ratios between benign and malignant prostate tissues: Cancer association of annexin A3
Authors: Wozny Wojciech , Schroer Klaus , Schwall Gerhard P. , Poznanović Slobodan , Stegmann Werner , Dietz Klaus , Rogatsch Hermann , Schaefer Georg , Huebl Heidi , Klocker Helmut , Schrattenholz André , Cahill Michael A.
Published: January 2007

A differential quantitative protein expression study, comparing matched prostate cancerous and benign tissues from 31 patients, revealed proteins newly associated with prostate cancer. Average effects for 17 proteins whose abundance was significantly different (p<0.01) across patients ranged from 1.5‐ to 6.1‐fold, and included a number of known cancer markers. The most differentially abundant proteins between cancer and benign samples were isopeptidase T, serum amyloid P (SAP), annexin A3 (ANXA3) and mitochondrial enoyl coenzyme‐A hydratase. SAP is restricted to stroma in healthy tissue, and the lower abundance in tumours may be explained by the reduced stromal content. ANXA3 is present in healthy epithelial cells, exhibits strong staining in precancerous prostatic intraepithelial neoplasia, and is relatively less abundant in individual tumour cells of increasing Gleason pattern (GP), despite exhibiting higher overall tissue abundance in tumours. ANXA3 staining was predominantly cytoplasmic, yet nuclear localization was also observed. Strongly staining single cells, possibly phagocytes, were interspersed in highly dedifferentiated GP5 tumour areas among tumour cells without measurable ANXA3. Local recurrent androgen ablation therapy‐resistant tumours exhibit heterogenous low levels of ANXA3 staining. Results are discussed focussing on the potential implications for tumour tissues.
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry for metabolic flux analyses using isotope‐labeled ethanol
Authors: Hollemeyer Klaus , Velagapudi Vidya R. , Wittmann Christoph , Heinzle Elmar
Published: January 2007

We describe a novel method for the determination of the concentration and labeling degree of ethanol originating from 1‐13C‐labeling experiments. This method is suitable for high‐throughput metabolic flux analysis because of the possible parallel sample preparation and fast final analysis using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). In a closed vial containing culture supernatant, ethanol is enzymatically oxidized to acetaldehyde. The acetaldehyde formed evaporates and is readily trapped in a second enclosed but open vial containing acidified 2,4‐dinitrophenylhydrazine (DNPH). The 2,4‐acetaldehyde dinitrophenylhydrazone (Ac‐DNPH) that is formed is insoluble under these conditions. This leads to a constant conversion rate of the acetaldehyde produced from ethanol after 14 h minimum incubation time. MALDI‐TOFMS was used to quantify the formed Ac‐DNPH with [13C2]‐ethanol as internal standard. The relative signal intensities of the unlabeled ethanol derivative as well as of [1‐13C]‐ethanol were linearly related to the ethanol concentration within a range of 1 to 50 mM with a limit of detection of 0.6 mM, a range which is sufficient for flux analysis in microtiter plate fermentation experiments. The method allows the estimation of the [1‐13C]‐ethanol originating from 1‐13C‐labeling experiments of Saccharomyces cerevisiae strains. In experiments where the expected flux range was exceeded, unlabeled ethanol was determined with a linear range from 30 to 500 mM. Ethanol quantification using this method was compared with enzymatic analysis and exhibited differences of less than 3.3% on average. Comparison of flux partitioning ratios between glycolysis and the pentose‐phosphate pathway (PPP) based on MALDI‐TOFMS and gas chromatography (GC)/MS methods showed good agreement, with differences for ethanol and alanine labeling of only 4.3%. Copyright © 2007 John Wiley & Sons, Ltd.
Sebacic acid and 2‐octanol from castor oil
Authors: Vasishtha A. K. , Trivedi R. K. , Das G.
Published: January 2007

Alkali pyrolysis of castor oil was carried out in the presence of white mineral oil. The operating parameters were optimized to obtain high yields of 2‐octanol and sebacic acid. Alkali pyrolysis at 280±2°C in the presence of 1% red lead catalyst yielded 70.1% 2‐octanol and 72.5% sebacic acid on the basis of their respective theoretical yields.
The specific refraction of fatty oils
Authors: Tels M. , Kruidenier A. J. , Boelhouwer C. , Waterman H. I.
Published: January 2007

It is shown that atomic and group refractions, obtained from data on hydrocarbons, may be used in calculating the Lorenz‐Lorentz molar refraction of fatty acid esters.

By assuming that the various atomic and group refractions are additive in mixtures of fatty acid esters, a relation between the iodine value, the saponification value, and the specific refraction of fatty oils is derived. The validity of this relation is confirmed by comparing the calculated and the experimentally determined specific refractions of a number of fatty oils and their hydrogenation products.

From this relation a diagram for the graphical‐statistical analysis of glycerides of nonconjugated, nonpolymerized, straight‐chain fatty acids is developed.
The preparation and properties of surface‐active N‐acylamino‐methanesulfonates
Authors: Falk Robert A. , Gerecht J. Fred , Krems Irving J.
Published: January 2007

The preparation and properties of aminomethanesulfonic acid and several of its lower and higher N‐alkyl derivatives have been studied. The acylation of these compounds was investigated, and the optimum conditions were determined. Measurements of the surface‐active properties, including pour foam, soil removal, and redeposition, of several of the acylated derivatives are described, with reference to Igepon T.
Detergent bars from salts ofa‐sulfonated tallow acids
Authors: Weil J. K. , Stirton A. J. , Maurer E. W. , Ault W. C. , Palm W. E.
Published: January 2007

Summary and Conclusions

Experimental detergent bars were based entirely on selected salts of α‐sulfonated saturated tallow acids. Some compositions appear to merit further investigation for the production of finished detergent bars, and an opportunity exists for the discovery of favorable combinations with soap. General conclusions are these.

Attractive detergent bars can be made from the monosodium or monoammonium salt [RCH (SO3M)CO2H] by partial neutralization with an amine or mixture of amines. Representative bars had the following compositions in mole percentage, anhydrous basis: a) 72 monosodium, 20 sodium ammonium, 8 sodium triethanolammonium salts; b) 85 monoammonium, 15 ammonium ethanolammonium salts.

Hardness and solubility can be controlled by water content and particularly by choice of the amine and the extent of the partial neutralization. Triethanolamine, isopropanolamine, and triethylamine tend to produce softer and more soluble bars than do ethanolamine or ethylamine.

The following compositions were suitable for detergent bars useful in sea water: a) 80 mole percentage of disodium 20 acid triethanolammonium; b) 20 monosodium, 50 sodium ammonium, 30 sodium triethanolammonium.
Effects of double bond configuration on lecithin synthesis
Authors: Lands W. E. M.
Published: January 2007

Stearyl‐CoA, oleyl‐CoA and elaidyl‐CoA were prepared and tested as substances in synthesizing lecithin from 1‐ and 2‐acyglycerol‐3‐phosphorylcholine. The rates of acyltransfer were followed by a continuous spectrophotometric assay. The enzyme(s) used to catalyze esterification at the 2‐position did not discriminate appreciably between thecis andtrans isomers of octadecenoate and transferred them more rapidly than the saturated acid, octadecanoate. However, the enzyme(s) which acted at the 1‐position discriminated markedly between the geometric isomers and rapidly transferred totrans‐ octadecenoate and octadecanoate.
General safety in handling solvents
Authors: Smalling J. W.
Published: January 2007

There are two major requirements for safety in plant operations: 1) convince everyone that it is smart to be safe, and 2) make it easier to be safe than unsafe. The most important method of instituting a workable and reliable safety program is that the general safety philosophy must be truly believed by management and promoted by them. It is only in this atmosphere that plant personnel will be able to progress to an outstanding safety record. The procedures for safer plant operations and general safety is a continuing program, and must be reviewed and revised, when required, in order to enhance safer operations.
Analytical techniques for hydroxy acids in fats and oils
Authors: Applewhite T. H.
Published: January 2007

Recent work on separation techniques such as column, thin‐layer, gas‐liquid, and liquid‐liquid partition chromatography; chemical and physical characterization techniques, e.g., derivatization, X‐ray, infrared, nuclear magnetic resonance and mass spectrometry; and the possibilities for qualitative and quantitative analysis using these and other methods are discussed.
Determination of copper in edible soybean oils
Authors: List G. R. , Hoffmann R. L. , Kwolek W. F. , Evans C. D.
Published: January 2007

Soybean oils have been analyzed for their copper content before and after hydrogenation with copper‐containing catalysts. A low‐temperature dry asher, an apparatus in which oxygen plasma is generated in a radio frequency field under high vacuum, was adopted for ashing glyceride oils. The residues were analyzed by a colorimetric procedure using zinc dibenzyldi‐thiocarbamate as the reagent. Identical samples were analyzed without ashing by neutron activation and atomic absorption techniques. The accuracy of the methods was determined by adding known amounts of copper at four different levels to two different soybean salad oils. Plots of copper found versus added copper showed that results were consistent over the range 0.04–5.0 ppm for all three methods, but that the atomic absorption results were low. The relative error of a single determination was ±13% and that of the mean of duplicate determinations ±9%. Analysis of natural soybean oils showed a copper content of about 0.03–0.10 ppm, whereas the same oils hydrogenated with cooper‐containing catalysts and without metal removal treatments had levels of 3–5 ppm.