bluuebunny/crossref_metadata_2025 huggingface dataset:
The TRAPP Complex: Insights into its Architecture and Function
Authors: Sacher Michael , Kim Yeon‐Gil , Lavie Arnon , Oh Byung‐Ha , Segev Nava
Published: September 2008

Vesicle‐mediated transport is a process carried out by virtually every cell and is required for the proper targeting and secretion of proteins. As such, there are numerous players involved to ensure that the proteins are properly localized. Overall, transport requires vesicle budding, recognition of the vesicle by the target membrane and fusion of the vesicle with the target membrane resulting in delivery of its contents. The initial interaction between the vesicle and the target membrane has been referred to as tethering. Because this is the first contact between the two membranes, tethering is critical to ensuring that specificity is achieved. It is therefore not surprising that there are numerous ‘tethering factors’ involved ranging from multisubunit complexes, coiled‐coil proteins and Rab guanosine triphosphatases. Of the multisubunit tethering complexes, one of the best studied at the molecular level is the evolutionarily conserved TRAPP complex. There are two forms of this complex: TRAPP I and TRAPP II. In yeast, these complexes function in a number of processes including endoplasmic reticulum‐to‐Golgi transport (TRAPP I) and an ill‐defined step at the trans Golgi (TRAPP II). Because the complex was first reported in 1998 (1), there has been a decade of studies that have clarified some aspects of its function but have also raised further questions. In this review, we will discuss recent advances in our understanding of yeast and mammalian TRAPP at the structural and functional levels and its role in disease while trying to resolve some apparent discrepancies and highlighting areas for future study.
Metabolic response of Pseudomonas putida during redox biocatalysis in the presence of a second octanol phase
Authors: Blank Lars M. , Ionidis Georgios , Ebert Birgitta E. , Bühler Bruno , Schmid Andreas
Published: September 2008

A key limitation of whole‐cell redox biocatalysis for the production of valuable, specifically functionalized products is substrate/product toxicity, which can potentially be overcome by using solvent‐tolerant micro‐organisms. To investigate the inter‐relationship of solvent tolerance and energy‐dependent biocatalysis, we established a model system for biocatalysis in the presence of toxic low logPow solvents: recombinant solvent‐tolerant Pseudomonas putida DOT‐T1E catalyzing the stereospecific epoxidation of styrene in an aqueous/octanol two‐liquid phase reaction medium. Using 13C tracer based metabolic flux analysis, we investigated the central carbon and energy metabolism and quantified the NAD(P)H regeneration rate in the presence of toxic solvents and during redox biocatalysis, which both drastically increased the energy demands of solvent‐tolerant P. putida. According to the driven by demand concept, the NAD(P)H regeneration rate was increased up to eightfold by two mechanisms: (a) an increase in glucose uptake rate without secretion of metabolic side products, and (b) reduced biomass formation. However, in the presence of octanol, only ∼ 1% of the maximally observed NAD(P)H regeneration rate could be exploited for styrene epoxidation, of which the rate was more than threefold lower compared with operation with a non‐toxic solvent. This points to a high energy and redox cofactor demand for cell maintenance, which limits redox biocatalysis in the presence of octanol. An estimated upper bound for the NAD(P)H regeneration rate available for biocatalysis suggests that cofactor availability does not limit redox biocatalysis under optimized conditions, for example, in the absence of toxic solvent, and illustrates the high metabolic capacity of solvent‐tolerant P. putida. This study shows that solvent‐tolerant P. putida have the remarkable ability to compensate for high energy demands by boosting their energy metabolism to levels up to an order of magnitude higher than those observed during unlimited growth.
Inactivation of colicin Y by intramembrane helix–helix interaction with its immunity protein
Authors: Šmajs David , Doležalová Magda , Macek Pavel , Žídek Lukáš
Published: September 2008

The construction of hybrids between colicins U and Y and the mutagenesis of the colicin Y gene (cya) have revealed amino acid residues important for interactions between colicin Y and its cognate immunity protein (Cyi). Four such residues (I578, T582, Y586 and V590) were found in helices 8 and 9 of the colicin Y pore‐forming domain. To verify the importance of these residues, the corresponding amino acids in the colicin B protein were mutated to the residues present in colicin Y. An Escherichia coli strain with cloned colicin Y immunity gene (cyi) inactivated this mutant, but not the wild‐type colicin B. In addition, interacting amino acid pairs in Cya and Cyi were identified using a set of Cyi point mutant strains. These data are consistent with antiparallel helix–helix interactions between Cyi helix T3 and Cya helix 8 of the pore‐forming domain as a molecular mechanism of colicin Y inactivation by its immunity protein.
N‐Acetylcysteine Improves the Clinical Conditions of Mustard Gas‐Exposed Patients with Normal Pulmonary Function Test
Authors: Ghanei Mostafa , Shohrati Majid , Jafari Mehrdad , Ghaderi Soleyman , Alaeddini Farshid , Aslani Jafar
Published: September 2008

Abstract:  Administration of N‐acetylcysteine may be effective in diseases caused by oxidative–antioxidative imbalance. We aimed to determine the effect administration for 4 months of N‐acetylcysteine (1200 mg daily) on sulfur mustard‐induced bronchiolitis obliterans in patients with normal pulmonary function test. In a double‐blind clinical trial, 144 patients with bronchiolitis obliterans due to sulfur mustard and bronchiolitis obliterans syndrome class 0, randomly entered to group 1 (n = 72, N‐acetylcysteine) and group 2 (n = 72, placebo). The changes in dyspnoea, wake‐up dyspnoea, cough and sputum were measured after 4 months using a ‘delta value’ (i.e. symptom score after 4 months – symptom score before the trial). Spirometric findings were measured at the beginning of the trial, 2 months later and 4 months later. Dyspnoea (delta value: –0.78 (0.61), P < 0.001), wake‐up dyspnoea (delta value: –0.57 (0.64), P < 0.001), and cough (delta value: –0.86 (0.63), P < 0.001) improved after 4 months of N‐acetylcysteine administration compared to the control group. N‐acetylcysteine reduced sputum from 76.9% (n = 40) of cases before the trial to 9.6% (n = 5) of cases after the trial. Spirometric components were significantly improved in N‐acetylcysteine group compared to the placebo group: FEV1 (P < 0.0001), FVC (P = 0.014) and FEV1/FVC (P = 0.003). A 4‐month trial with 1200 mg oral N‐acetylcysteine per day can be used for treating bronchitis, but is also effective in treating bronchiolitis. It also prevents sulfur mustard‐induced oxidative stress, and can be used in the treatment of sulfur mustard‐induced pulmonary disease.
Analysis of Methods to Estimate Spring Flows in a Karst Aquifer
Authors: Sepúlveda Nicasio
Published: September 2008

Hydraulically and statistically based methods were analyzed to identify the most reliable method to predict spring flows in a karst aquifer. Measured water levels at nearby observation wells, measured spring pool altitudes, and the distance between observation wells and the spring pool were the parameters used to match measured spring flows. Measured spring flows at six Upper Floridan aquifer springs in central Florida were used to assess the reliability of these methods to predict spring flows. Hydraulically based methods involved the application of the Theis, Hantush‐Jacob, and Darcy‐Weisbach equations, whereas the statistically based methods were the multiple linear regressions and the technology of artificial neural networks (ANNs). Root mean square errors between measured and predicted spring flows using the Darcy‐Weisbach method ranged between 5% and 15% of the measured flows, lower than the 7% to 27% range for the Theis or Hantush‐Jacob methods. Flows at all springs were estimated to be turbulent based on the Reynolds number derived from the Darcy‐Weisbach equation for conduit flow. The multiple linear regression and the Darcy‐Weisbach methods had similar spring flow prediction capabilities. The ANNs provided the lowest residuals between measured and predicted spring flows, ranging from 1.6% to 5.3% of the measured flows. The model prediction efficiency criteria also indicated that the ANNs were the most accurate method predicting spring flows in a karst aquifer.
Androgen replacement therapy improves function in male rat muscles independently of hypertrophy and activation of the Akt/mTOR pathway
Authors: Hourdé C. , Jagerschmidt C. , Clément‐Lacroix P. , Vignaud A. , Ammann P. , Butler‐Browne G. S. , Ferry A.
Published: September 2008

Aim:  We analysed the effect of physiological doses of androgens following orchidectomy on skeletal muscle and bone of male rats, as well as the relationships between muscle performance, hypertrophy and the Akt/mammalian target of rapamycin (mTOR) signalling pathway involved in the control of anabolic and catabolic muscle metabolism.

Methods:  We studied the soleus muscle and tibia from intact rats (SHAM), orchidectomized rats treated for 3 months with vehicle (ORX), nandrolone decanoate (NAN) or dihydrotestosterone (DHT).

Results:  Orchidectomy had very little effect on the soleus muscle. However, maximal force production by soleus muscle (+69%) and fatigue resistance (+35%) in NAN rats were both increased when compared with ORX rats. In contrast, DHT treatment did not improve muscle function. The relative number of muscle fibres expressing slow myosin heavy chain and citrate synthase activity were not different in NAN and ORX rats. Moreover, NAN and DHT treatments did not modify muscle weights and cross‐sectional area of muscle fibres. Furthermore, phosphorylation levels of downstream targets of the Akt/mTOR signalling pathway, Akt, ribosomal protein S6 and eukaryotic initiation factor 4E‐binding protein 1 were similar in muscles of NAN, DHT and ORX rats. In addition, trabecular tibia from NAN and DHT rats displayed higher bone mineral density and bone volume when compared with ORX rats. Only in NAN rats was this associated with increased bone resistance to fracture.

Conclusion:  Physiological doses of androgens are beneficial to muscle performance in orchidectomized rats without relationship to muscle and fibre hypertrophy and activation of the Akt/mTOR signalling pathway. Taken together our data clearly indicate that the activity of androgens on muscle and bone could participate in the global improvement of musculoskeletal status in the context of androgen deprivation induced by ageing.
The Mathematical Assessment of Long‐Range Linguistic Relationships
Authors: Kessler Brett
Published: September 2008

Language classification differs from biological cladistics in that monogenesis cannot be assumed. Before a cladogram or family tree can be accepted, linguists must be convinced that the languages are related at all. Morpheme tables, or word lists, provide a good framework for investigating relatedness, but methodologies for quantifying and assessing the data statistically are still being developed. The comparative method furnished a viable statistic, recurrent sound correspondences, but by no means to see whether they exceeded levels expected by chance. Organizing correspondences into contingency tables permitted hypothesis testing, with Monte Carlo resampling methods providing the flexibility to support a wide variety of test statistics, including different ways of computing sound recurrences and phonetic similarity. Thus, techniques from both the comparative method and multilateral comparison can be deployed with rigorous numeric assessment. Experiments seek to increase the power of the tests to explore new hypotheses and verify long‐range language relationships.
Khoisan Languages
Authors: König Christa
Published: September 2008

Khoisan is not a genetic unit. It consists of at least five independent lineages. Typologically, the Khoisan languages show the following dichotomy. The Khoe languages (formerly Central Khoisan) share features such as verb‐final constituent order, an amalgamated marking of person–gender–number (called pgn), and a case‐like object .marker. The remaining South African Khiosan languages (formerly Northern and Southern Khoisan) again share salient features such as a noun‐class system, and a serial verb construction of a contiguous, asymmetrical type, and a distinctly more complex phonological system.
Rehydration of Freeze‐Dried and Convective Dried Boletus edulis Mushrooms: Effect on Some Quality Parameters
Authors: Hernando I. , Sanjuán N. , Pérez‐Munuera I. , Mulet A.
Published: September 2008

ABSTRACT:  Quality of rehydrated products is a key aspect linked to rehydration conditions. To assess the effect of rehydration temperature on some quality parameters, experiments at 20 and 70 °C were performed with convective dried and freeze‐dried Boletus edulis mushrooms. Rehydration characteristics (through Peleg's parameter, k1, and equilibrium moisture, We), texture (Kramer), and microstructure (Cryo‐Scanning Electron Microscopy) were evaluated. Freeze‐dried samples absorbed water more quickly and attained higher We values than convective dried ones. Convective dehydrated samples rehydrated at 20 °C showed significantly lower textural values (11.9 ± 3.3 N/g) than those rehydrated at 70 °C (15.7 ± 1.2 N/g). For the freeze‐dried Boletus edulis, the textural values also exhibited significant differences, being 8.2 ± 1.3 and 10.5 ± 2.3 N/g for 20 and 70 °C, respectively. Freeze‐dried samples showed a porous structure that allows rehydration to take place mainly at the extracellular level. This explains the fact that, regardless of temperature, freeze‐dried mushrooms absorbed water more quickly and reached higher We values than convective dried ones. Whatever the dehydration technique used, rehydration at 70 °C produced a structural damage that hindered water absorption; consequently lower We values and higher textural values were attained than when rehydrating at 20 °C.
Hypocholesterolemic and Anti‐Obesity Effects of Saponins from Platycodon grandiflorum in Hamsters Fed Atherogenic Diets
Authors: Zhao H.L. , Harding S.V. , Marinangeli C.P.F. , Kim Y.S. , Jones P.J.H.
Published: September 2008

ABSTRACT:  Platycodins, a group of saponin glycosides from Platycodon grandiflorum, are believed to possess anti‐obesity and cholesterol‐lowering properties. The aim of the present study was to investigate whether dietary platycodins affect plasma, hepatic, or fecal cholesterol concentrations, as well as cholesterol absorption and fractional synthesis rates in a dose‐dependent manner. Golden Syrian hamsters (n= 45) were fed atherogenic (0.25% cholesterol) diets enriched with platycodins in the forms of either aqueous extracts (containing 0.3% to 0.5% of platycodins of diet mass) or crude saponins fractions (containing 0.9% to 1.0% of platycodins of diet mass) for 28 d. {3, 4}−13C‐cholesterol and 2H2O tracers were administered on days 26 and 28 to assess cholesterol absorption and biosynthesis, respectively. After platycodin intervention, total cholesterol concentrations in plasma and liver were reduced (P < 0.05) by 13% to 28% and 41% to 79%, respectively, whereas cholesterol concentrations in feces were increased (P < 0.05) up to 2.5‐fold compared to controls. Platycodin feeding increased (P < 0.001) cholesterol absorption up to 60%, but not cholesterol synthesis. These results suggest that platycodin‐enriched diets can lower circulating and whole body cholesterol contents, and thus reduce the risk of cardiovascular diseases through mechanisms independent from cholesterol absorption or synthesis.
Impact of Overall and Particle Surface Heat Transfer Coefficients on Thermal Process Optimization in Rotary Retorts
Authors: Simpson R. , Abakarov A. , Almonacid S. , Teixeira A.
Published: September 2008

ABSTRACT:  This study attempts to examine the significance of recent research that has focused on efforts to estimate values for global and surface heat transfer coefficients under forced convection heating induced by end‐over‐end rotation in retorting of canned peas in brine. The study confirms the accuracy of regression analysis used to predict values for heat transfer coefficients as a function of rotating speed and headspace, and uses them to predict values over a range of process conditions, which make up the search domain for process optimization. These coefficients were used in a convective heat transfer model to establish a range of lethality‐equivalent retort temperature–time processes for various conditions of retort temperature, rotating speed, and headspace. Then, they were coupled with quality factor kinetics to predict the final volume average and surface quality retention resulting from each process and to find the optimal thermal process conditions for canned fresh green peas. Results showed that maximum quality retention (surface and volume average retention) was achieved with the shortest possible process time (made possible with highest retort temperature), and reached the similar level in all cases with small difference between surface and volume average quality retention. The highest heat transfer coefficients (associated with maximum rotating speed and headspace) showed a 10% reduction in process time over that required with minimum rotating speed and headspace. The study concludes with a discussion of the significance of these findings and degree to which they were expected.
Inhibitory Effect of Morinda Citrifolia L. on Lipoprotein Lipase Activity
Authors: Pak‐Dek M.S. , Abdul‐Hamid A. , Osman A. , Soh C.S.
Published: September 2008

ABSTRACT:  Efficacy of Morinda citrifolia L. leaf (MLE) and fruit extracts (MFE) in inhibiting lipoprotein lipase (LPL) was determined in vitro. The result of the study showed that the highest inhibition on the LPL activity was exhibited by MLE (66%± 2.1%), which is significantly higher than that demonstrated by MFE (54.5%± 2.5%), green tea extract (GTE) (54.5%± 2.6%), and catechin (43.6%± 6.1%). Percent of LPL inhibition increase with concentration of the extracts. Quantitative analysis of the extracts revealed the presence of high levels of (+)−catechin at 63.5 ± 17 and 53.7 ± 5.7 mg/g in MLE and MFE, respectively, although not as high as that found in GTE (530.6 ± 42 mg/g). Appreciable amount of epicatechin was found in all extracts tested, while rutin was only found in MLE and MFE. The study suggested that both leaf and fruit of M. citrifolia may be used as antiobesity agents in body weight management.
Fractional Differential Equations Based Modeling of Microbial Survival and Growth Curves: Model Development and Experimental Validation
Authors: Kaur A. , Takhar P.S. , Smith D.M. , Mann J.E. , Brashears M.M.
Published: September 2008

ABSTRACT:  A fractional differential equations (FDEs)‐based theory involving 1‐ and 2‐term equations was developed to predict the nonlinear survival and growth curves of foodborne pathogens. It is interesting to note that the solution of 1‐term FDE leads to the Weibull model. Nonlinear regression (Gauss–Newton method) was performed to calculate the parameters of the 1‐term and 2‐term FDEs. The experimental inactivation data of Salmonella cocktail in ground turkey breast, ground turkey thigh, and pork shoulder; and cocktail of Salmonella, E. coli, and Listeria monocytogenes in ground beef exposed at isothermal cooking conditions of 50 to 66 °C were used for validation. To evaluate the performance of 2‐term FDE in predicting the growth curves—growth of Salmonella typhimurium, Salmonella Enteritidis, and background flora in ground pork and boneless pork chops; and E. coli O157:H7 in ground beef in the temperature range of 22.2 to 4.4 °C were chosen. A program was written in Matlab to predict the model parameters and survival and growth curves. Two‐term FDE was more successful in describing the complex shapes of microbial survival and growth curves as compared to the linear and Weibull models. Predicted curves of 2‐term FDE had higher magnitudes of R2 (0.89 to 0.99) and lower magnitudes of root mean square error (0.0182 to 0.5461) for all experimental cases in comparison to the linear and Weibull models. This model was capable of predicting the tails in survival curves, which was not possible using Weibull and linear models. The developed model can be used for other foodborne pathogens in a variety of food products to study the destruction and growth behavior.
The Authenticity of Self: Conceptualization, Personal Experience, and Practice
Authors: Vannini Phillip , Franzese Alexis
Published: September 2008

Scholars across the social sciences often use the concept of authenticity to refer to such different things as sincerity, truthfulness, originality, and the feeling and practice of being true to one's self or others. Whereas the concept of authenticity refers to all of these things, a careful employment of this concept requires a clear understanding of it. By reviewing theory and empirical research on authenticity, we aim at a more precise conceptualization of authenticity. We argue that authenticity is about being true to one's self. When one is true to one's self, one experiences authenticity. This conceptualization views authenticity as a self‐reflective and emotional experience. In order to understand authenticity, a researcher must then take into consideration at least two things: people's emotional experiences of being true or untrue to one's self and people's ideas about what their true self is.
Resisting the Neo‐liberal Poverty Discourse: On Constructing Deadbeat Dads and Welfare Queens
Authors: Cassiman Shawn A.
Published: September 2008

This article describes the impact of both neo‐liberal and conservative discourse upon poverty policy and welfare reform. In it, I summarize the discursive construction of welfare queens and deadbeat dads and the influence upon welfare reform while incorporating globalization in the discursive critique. This paper also describes the resistance to the discourse evidenced by those most affected by the poverty or welfare reform discourse. I suggest ways of critically examining our own discourse as well as the welfare reform discourse and our participation in it or resistance to it. The conclusion questions assumptions about dependency, welfare receipt and justice.
Ultraviolet wavebands and melanoma initiation
Authors: Bennett Dorothy C.
Published: September 2008

In view of claims that ultraviolet radiation‐emitting sunbeds are safe, or safe when they emit only longer wavelengths, research findings are reviewed here on the effects of ultraviolet wavebands A and B (UVA, 315–400 nm and UVB, 290–315 nm) on mutagenesis and carcinogenesis in skin, with particular reference to melanocytes and melanoma. Both UVA and UVB radiation have been shown to induce mutations, as well as mutagenic photoproducts such as cyclobutane pyrimidine dimers, in human skin. UVB can induce melanoma in susceptible mice and in xenografted human skin engineered to express melanocyte growth factors. There is evidence for photosensitization of melanocytes by melanin, especially pheomelanin. UVA can induce melanoma in pigmented fish, and melanocytic hyperplasia in pigmented opossums, but has not generally been tested for melanoma induction in pigmented mammals or in human skin. There is no experimental basis for a claim that UVA is safe, and recreational exposure to this known mutagen should be discouraged.
Long‐term biomechanical properties of rabbit sclera after collagen crosslinking using riboflavin and ultraviolet A (UVA)
Authors: Wollensak Gregor , Iomdina Elena
Published: September 2008

Purpose:  Scleral crosslinking by the photosensitizer riboflavin and ultraviolet A (UVA) has been shown to increase significantly the scleral biomechanical rigidity and might therefore become a possible sclera‐based treatment modality for progressive myopia. In the present study, the long‐term effect of the new crosslinking method on biomechanical properties was investigated in the rabbit sclera.

Methods:  A 10 × 10 mm sector of the equatorial sclera of nine Chinchilla rabbit eyes was treated in vivo using a UVA double diode of 370 nm with a surface irradiance of 3 mW/cm2 and application of 0.1% riboflavin‐5‐phosphate drops as photosensitizer for 30 min. Three days, 4 months and 8 months postoperatively, biomechanical stress–strain measurements of the treated scleral strips were performed and compared to contralateral control sclera using a microcomputer‐controlled biomaterial tester. In addition, routine histological controls were performed.

Results:  Following the crosslinking treatment, Young’s modulus was increased by 320% after 3 days, 277% after 4 months and 502% after 8 months, and ultimate stress by 341% after 3 days, 131% after 4 months and 213.8% after 8 months versus the controls. The decrease in ultimate strain was between 24% and 44.8%. On histology, no tissue damage was detected.

Conclusion:  Our new method of scleral collagen crosslinking proved very effective and constant over a time interval of up to 8 months in increasing the scleral biomechanical strength. Therefore, the new treatment might become an option for strengthening scleral tissue in progressive myopia and other conditions associated with weakened sclera. There were no side‐effects on the retina or retinal pigment epithelium. The new crosslinking treatment could now be tested in a suitable myopia model (like the tree shrew) and finally in human eyes.
Analysis of Stiffness and Elastic Deformation for Some 3–5-DOF PKMs With SPR or RPS-type legs
Authors: Lu Yi , Hu Bo
Published: September 2008

This paper proposes an equivalent mechanism approach for establishing the stiffness matrices of some 3–5DOF (degree of freedom) parallel kinematic machines (PKMs) with SP̱R- or RP̱S-type legs and solving their elastic deformations. First, the geometric constraints of constrained wrench of these PKMs are analyzed, and the poses of the active/constrained forces are determined. Second, based on the principle of virtue work and the determined active/constrained forces, the formulas are derived for solving the 6×6 Jacobian matrices of these PKMs and the stiffness matrices of SP̱R or RP̱S-type active legs. Third, based on the elastic deformations of the SP̱R or RP̱S active legs, the equivalent 6-DOF rigid PKMs of these elastic PKMs are constructed, and their 6×6 Jacobian matrices are derived. Finally, the formulas are derived for solving the total stiffness matrices and the elastic deformation of the 3DOF 3SP̱R, 3DOF 3RP̱S, 4DOF 2SP̱S+2SP̱R, and 5DOF 4SP̱S+SP̱R PKMs.
On the Joint Velocity Jump for Redundant Robots in the Presence of Locked-Joint Failures
Authors: Jing Zhao , Qian Li
Published: September 2008

The joint velocity jump for redundant robots in the presence of locked-joint failures is discussed in this paper. First, the analytical formula of the optimal joint velocity with minimum jump is derived, and its specific expressions for both all joint failure and certain single joint failure are presented. Then, the jump difference between the minimum jump solution and the least-norm velocity solution is mathematically analyzed, and the influence factors on this difference are also discussed. Based on this formula, a new fault tolerant algorithm with the minimum jump is proposed. Finally, simulation examples are implemented with a planar 3R robot and a 4R spatial robot, and an experimental study is also done. Study results indicate that the new algorithm proposed in this paper is well suited for real time implementation, and can further reduce the joint velocity jump thereby improving the motion stability of redundant robots in fault tolerant operations. Also, the fewer the possible failed joints are, the more obvious the effect of this new algorithm becomes.
Assessment of Current Continuous Hemofiltration Systems and Development of a Novel Accurate Fluid Management System for Use in Extracorporeal Membrane Oxygenation
Authors: Sucosky Philippe , Dasi Lakshmi P. , Paden Matthew L. , Fortenberry James D. , Yoganathan Ajit P.
Published: September 2008

Extracorporeal membrane oxygenation (ECMO) with a renal replacement therapy such as continuous venovenous hemofiltration (CVVH) provides life-saving temporary heart and lung, and renal support in pediatric and neonatal intensive care units. However, studies have shown that this approach may be hampered due to the potentially inaccurate fluid delivery∕drainage of current intravenous (IV) fluid pumps, creating potential for excessive fluid removal and undesired degrees of dehydration. We present a simple and novel accurate fluid management system capable of working against the high volume flow and pressures typically seen in patients on ECMO. The accuracy of the in-line system implemented at Children’s Healthcare of Atlanta at Egleston was assessed experimentally. The data assisted in the development of a novel automated and accurate fluid management system that functions based on a conservation of volume approach to limit the inaccuracies observed in typical clinical implementations of CVVH. IV pump accuracy measurements demonstrated a standard error in net ultrafiltrate volume removed from the patient of up to 848.5±156ml over a period of 24h, supporting previous observations of patient’s dehydration during the course of a combined ECMO-CVVH treatment and justifying the need for a new fluid management system. The innovative design of the new device is expected to achieve either a perfect or controlled negative fluid balance between the ultrafiltrate and replacement fluid flow rates. Perfect fluid balance is achieved by imposing an identical displacement on two pistons, one delivering replacement fluid to the circuit and the other draining ultrafiltrate from the hemofilter. Fluid removal is managed via a second syringe-pump system that reduces the net replacement fluid flow rate with respect to the ultrafiltration flow rate. The novel fluid management system described in this paper is expected to provide an effective method to control precisely fluid flow rates in patients on ECMO. Therefore, this device could potentially improve the efficacy of ECMO therapy and constitute a safe and effective way of reducing fluid overload in patients with cardiorespiratory failure.
Evaluation and Design of Displacement-Amplifying Compliant Mechanisms for Sensor Applications
Authors: Krishnan Girish , Ananthasuresh G. K.
Published: September 2008

Displacement-amplifying compliant mechanisms (DaCMs) reported in literature are widely used for actuator applications. This paper considers them for sensor applications that rely on displacement measurement, and proposes methods to evaluate and design such mechanisms. The motivation of this work is to increase the sensitivity of a micromachined capacitive accelerometer and a minute mechanical force sensor using DaCMs. A lumped spring-mass-lever (SML) model, which effectively captures the effects of appending a DaCM to a sensor, is introduced. This model is a generalization of the ubiquitously used spring-mass model for the case of an elastic body that has two points of interest—an input and an output. The SML model is shown to be useful in not only evaluating the suitability of an existing DaCM for a new application but also for designing a new DaCM. With the help of this model, we compare a number of DaCMs from literature and identify those that nearly meet the primary problem specifications. To obtain improved designs that also meet the secondary specifications, topology and size-optimization methods are used. For the two applications considered in this paper, we obtain a few new DaCM topologies, which are added to the catalog of DaCMs for future use. The spring-mass-lever model, the evaluation and design methods, and the catalog of DaCMs presented here are useful in other sensor and actuator applications.
Face Gear Width Prediction Using the DOE Method
Authors: Guingand Michèle , Remond Didier , de Vaujany Jean-Pierre
Published: September 2008

This paper deals with face gear design. The goal is to propose a simple formula for predicting the width of the wheel as a function of the main design parameters. A specific software was used to achieve this goal. This numerical tool is able to simulate the geometry and the quasistatic loaded behavior of a face gear. The statistical method used for analyzing the influence of data is described: The design of experiments leads to a simple regression model taking into account the influential parameters and their couplings. In the last part of this paper, the results of the formulas are compared to those of the software and an optimal design is proposed based on the regression model.
Design and Analysis of a Class of Planar Biped Robots Mechanically Coordinated by a Single Degree of Freedom
Authors: McKendry J. , Brown B. , Westervelt E. R. , Schmiedeler J. P.
Published: September 2008

This paper presents a method of integrating mechanism design and hybrid system analysis for the design of single-degree-of-freedom (DOF) planar biped robots that can achieve dynamic walking gaits that are stable. Reducing the DOF in a biped can result in a reduction in the complexity of the control strategies needed to enable stable walking. Although the biped designed by this procedure is restricted to a single gait, this biped may be less complex, lighter, and less costly to construct than one whose multiple DOFs are coordinated via feedback.
Mixing Efficiency of Red Blood Cells With Magnetic Microspheres for a Hybrid Separation System
Authors: Haik Yousef , Kanuri Sridhar
Published: September 2008

The mixing efficiency of red blood cells and magnetic microspheres with red blood cell tagging ability is investigated using color particle image velocimetry. A hybrid separation system that utilizes centrifugation and magnetic separation is described. Magnetic microspheres are utilized to isolate the red cells from the buffy coat on a continuous basis. The effectiveness of red blood cell separation from the buffy coat in the hybrid system was improved over conventional centrifugal separation methods.
Synthesis of a Pattern Generation Mechanism for Gait Rehabilitation
Authors: Ji Zhiming , Manna Yazan
Published: September 2008

Gait training is a major part of neurological rehabilitation. Robotic gait training systems provide paraplegic patients with consistent, labor-saving, and adjustable physical therapy over traditional manual trainings. However the high cost and social-technical concerns on safe operation currently limit their availability to only a few large rehabilitation institutions. This paper describes the synthesis of a linkage mechanism for gait pattern generation in a sagittal plane. The synthesis of the mechanism starts with the definition of a closed ankle trajectory obtained from normative gait data. The synthesis process we developed includes (1) construction of the desired ankle trajectory, (2) formulation of an objective function to be used for linkage optimization, (3) development of a procedure for transforming an initial guess to a starting set of design variables for optimization, and (4) development of a point-matching process needed for implementation. A set of stature-referenced parameters was successfully produced for a crank-rocker mechanism to generate the desired gait path. A simple linkage mechanism can be used as the pattern generator in a gait training system, and the presented process has been used to synthesize a linkage for a specific gait pattern.
High magnetization FeCo∕Pd multilayers
Authors: Walock M. J. , Ambaye H. , Chshiev M. , Klose F. R. , Butler W. H. , Mankey G. J.
Published: September 2008

We have fabricated multilayer samples with varying superlattice periodicity and interlayer thicknesses to determine the nature of the enhanced moment in this intriguing thin film system. Magnetic characterization experiments show an enhanced magnetic moment in the multilayers as compared to a single layer film containing the same amount of FeCo. However, since the magnetization is defined as the magnetic moment divided by the sample volume, the sample exhibits an overall reduction in the magnetization when the volume of the Pd layers is also taken into account. Our experimental findings are also supported by theoretical calculations which identify the origin of the increased magnetic moment in the multilayer system. Polarized neutron reflectivity experiments will be used to determine the lateral distribution of the magnetization in a number of superlattice samples.
Electronic states of Fe nanostructures on Pt(997) surface
Authors: Cheng Ruihua , Ayieta E. , Losovyj Ya. B.
Published: September 2008

A variety of one dimensional atomic chains can be synthesized on stepped surfaces, which provide opportunities for systematically tailoring the surface properties. The electronic structure of the high vicinal surface plays an essential role in determining the physical properties of the atomic chains. The authors have used surface analysis techniques to study the surface of Pt(997) single crystal. Angle resolved ultraviolet photoemission spectroscopy was performed to characterize the electronic states of Pt(997) surface by using a synchrotron radiation light source. Different from the expected free electron model on the flat Pt(111) surface, electron confinement is observed with a wave vector perpendicular to the step direction. Fe was carefully deposited onto Pt(997) substrate at room temperature. The STM data show that Fe atomic chains were formed along the step edges due to the step decoration growth. The exchange splitting of Fe 3d bands is estimated according to the photoemission spectroscopy data of Fe/Pt.
Ion beam deposition of tantalum pentoxide thin film at room temperature
Authors: Kulisch W. , Gilliland D. , Ceccone G. , Rauscher H. , Sirghi L. , Colpo P. , Rossi F.
Published: September 2008

Tantalum pentoxide (Ta2O5) thin films have been deposited by reactive ion beam sputtering at room temperature. The films have been characterized by scanning electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), variable angle ellipsometry, and UV-VIS spectroscopy. The main parameter varied was the oxygen partial pressure. Stoichiometry is reached for pO⩾3×10−2Pa; within the limit of XPS (∼1%) the films are free of contaminations. They are extremely smooth with a surface roughness of 0.14nm only. From FTIR, it can be concluded that they are amorphous. For stoichiometric Ta2O5 films, the refractive index at 532nm is in the range from 2.05 to 2.2, while the extinction coefficient is below the detection limit of our ellipsometer. UV-VIS spectra show stoichiometric films to possess a high transmission in a wide wavelength range with an absorption edge below 300nm.
Effect of structure and surface morphology of sol-gel derived TiO2 photoelectrode on the performance of dye-sensitized solar cells
Authors: Hossain M. F. , Biswas S. , Takahashi T. , Kubota Y. , Fujishima A.
Published: September 2008

Nanocrystalline TiO2 photoelectrodes were successfully deposited on SnO2:F coated glass substrate by sol-gel technique with different polyethylene glycol (PEG) concentrations. Low cost chlorophyllin based dye was used along with carbon paste on SnO2:F glass as a counterelectrode. All the TiO2 electrodes show good crystallinity. The x-ray diffraction result indicates that the TiO2 thin film without PEG has more compact structure with high density of crystallite. For TiO2 film with the same number of coatings, introduction of PEG induces porous structure with less number of crystallites. The amount of dye incorporation was found to be highly dependent on the microstructure of electrodes, as apparent from optical measurements. The result shows that the photoelectric conversion efficiency increases with PEG concentration, but the fill factor decreases monotonically. The variation of photoelectric conversion efficiency of the solar cells with different TiO2 electrodes prepared with various PEG concentrations is discussed with the analysis of different microstructures of the TiO2 photoelectrodes and the corresponding dye incorporation.
Temperature effect on the glancing angle deposition of Si sculptured thin films
Authors: Patzig Christian , Rauschenbach Bernd
Published: September 2008

Si sculptured thin films consisting of spiral-, screw-, and columnlike-shaped nanostructures were grown by ion beam-induced glancing angle deposition of Si on rotating bare Si[001] substrates at different substrate rotational speeds and substrate temperatures ranging from room temperature to (360±10)°C. For rotational speeds leading to the growth of nanoscrews at room temperature, morphology changes are observed with increasing temperature, such as an increase of the critical height at which single spiral fibers start merging to screws, thus giving the possibility to grow separated nanospirals with diameters of about 30 nm over a large thickness range. A decrease of the overall film thickness, indicating a change in the film density, is also observed with increasing the substrate temperature. For deposition conditions leading to the growth of vertical columns at room temperature, the substrate temperature influences the total number of columns, the column diameter, and the total structure height. The temperature-related changes in structure morphology show that surface diffusion effects play an important role in the morphological evolution of sculptured thin films consisting of helicoidal and columnlike structures during their growth by glancing angle deposition.
Efficient combining of ion pumps and getter-palladium thin films
Authors: Paolini C. , Mura M. , Ravelli F.
Published: September 2008

Nonevaporable getters (NEGs) have been extensively studied in the last several years for their sorption properties toward many gases. In particular, an innovative alloy as a thin film by magnetron sputtering was developed and characterized at the European Organization for Nuclear Research. It is composed of Ti–Zr–V and protected by an overlayer of palladium (Pd), according to a technology for which the authors got the licence. NEG-Pd thin films used in combination with ion getter pumps is a simple, easy way to handle pumping devices for ultrahigh and extremely high vacuum applications. To show how to apply this coating technology to the internal surface of different types of ion pumps, the authors carried out several tests on pumps of various shapes, sizes (in terms of nominal pumping speed), and types (diode, noble diode, and triode). Special care was taken during the thermal cycle of baking and activation of the pumps to preserve the internal film from sources of contamination and/or from the sputtering of the titanium cathodes of the pump. Some important remarks will be made about the most appropriate conditions of pressure and temperature. The performance of the NEG-Pd-coated ion pumps was evaluated in terms of ultimate pressure and hydrogen pumping speed. The contribution of the thin film is particularly relevant for the pumping of this gas, due to its high sticking factor on palladium and the great sorption capacity of the underlying getter. Finally, the possibility of further improvement by substituting palladium with other Pd-based alloys will also be evaluated.
Surface reactions during low-k etching using H2∕N2 plasma
Authors: Fukasawa Masanaga , Tatsumi Tetsuya , Oshima Keiji , Nagahata Kazunori , Uchida Saburo , Takashima Seigo , Hori Masaru , Kamide Yukihiro
Published: September 2008

We investigated the relationship between the hard mask faceting that occurs during organic low-k etching and the ion energy distribution function of a capacitively coupled plasma reactor. We minimized the hard mask faceting by precisely controlling the ion energy. This precise control was obtained by selecting the optimum bottom frequency and bias power. We measured the amount of damage done to a SiOCH film exposed to H2∕N2 plasma in order to find the H2∕N2 ratio at which the plasma caused the least damage. The amount of moisture uptake by the damaged SiOCH film is the dominant factor controlling the dielectric constant increase (Δk). To suppress Δk, the incident ion species and ion energies have to be precisely controlled. This reduces the number of adsorption sites in the bulk SiOCH and maintains the hydrophobic surface that suppresses water permeation during air exposure.
High rate deposition of photocatalytic TiO2 films by dc magnetron sputtering using a TiO2−x target
Authors: Sato Yasushi , Uebayashi Akira , Ito Norihiro , Kamiyama Toshihisa , Shigesato Yuzo
Published: September 2008

Photocatalytic TiO2 films were deposited on glass substrates by dc magnetron sputtering using a slightly reduced TiO2−x target (2−x=1.986; conductivity, 3.7 S cm−1; density, 4.21 g/cm3). The variation in the deposition rate as a function of the O2 flow ratio did not show a hysteresis curve at the “transition region” as seen in the case of a Ti metal target. The deposition rate using the TiO2−x target in 100% Ar gas was approximately seven times higher than that using the Ti metal target in an “oxide mode.” The films postannealed in air at temperatures ≥200 °C showed excellent photodecomposition characteristics of acetaldehyde (CH3CHO) as well as photoinduced hydrophilicity.
Preparation of TiO2 thin films by laser ablation for photocatalytic applications
Authors: Wang S. J. , Chang W.-T. , Ciou J.-Y. , Wei M.-K. , Wong M. S.
Published: September 2008

Thin titanium dioxide (TiO2) films were deposited by pulsed KrF excimer laser ablation deposition system using a titanium oxide target. The effects of substrate temperature and oxygen partial pressure on the phase formations of various microstructures were investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), Raman scattering spectroscopy, and UV-Vis spectrophotometer. The film structures range from amorphous to mixed phase of anatase and rutile to pure anatase. Increasing the substrate temperature improves the quality of anatase phase of crystalline TiO2 films. The oxygen pressure in the range between 15 and 60 mTorr shows a single anatase phase in TiO2 films while the rutile and anatase mixed phases were observed elsewhere. The band gap of TiO2 films varied from 2.72 to 3.27 eV with increasing oxygen partial pressure while the film structures changed from rutile phase to anatase phase. The surface area of TiO2 films increased as oxygen partial pressure in film deposition. The photocatalytic performance evaluated by degradation of methylene blue in UV light was distinguishable in the TiO2 films with high anatase phase and surface area.
Improvement of the surface roughness and sensing properties of cerium dioxide thin film by chemical mechanical polishing
Authors: Kim Nam-Hoon , Ko Pil-Ju , Lee Woo-Sun
Published: September 2008

Cerium dioxide (CeO2) is one of the most widely used materials for oxygen gas sensors. The surface roughness of CeO2 thin films must be improved because the electrical and sensing properties of CeO2 thin films are determined by these characteristics. The authors selected chemical mechanical polishing (CMP) processing for improving the surface roughness of CeO2 thin films. The authors examined the removal rate and surface roughness of spin coated CeO2 thin films with a change of CMP process parameters such as pressure (down force) and velocity (table speed). An optimized process condition, reflected by not only the surface roughness with a hillock-free surface but also an excellent removal rate with good uniformity, was obtained. The effects of the improved surface roughness on the sensing property of CeO2 thin films were also confirmed. The authors obtained improved sensitivity of CeO2 thin films for oxygen sensors after the CMP process by the improved surface morphology. Therefore, the authors concluded that the sensing property of CeO2 thin film was strongly dependent on the surface roughness of CeO2 thin films by using a CMP process.