bluuebunny/crossref_metadata_2025 huggingface dataset:
Colonisation of the oral cavity by periodontopathic bacteria in complete denture wearers
Authors: Yasui Masako , Ryu Masahiro , Sakurai Kaoru , Ishihara Kazuyuki
Published: September 2011

doi: 10.1111/j.1741‐2358.2011.00506.x

Colonisation of the oral cavity by periodontopathic bacteria in complete denture wearers

Objective:  The purpose of this study was to investigate colonisation by periodontopathic bacteria and the sites of colonisation in elderly upper and lower complete denture wearers. We also investigated the relationship between level of oral hygiene and colonisation by periodontopathic bacteria.

Materials and methods:  Forty edentulous and 37 dentate volunteers participated in this study. Samples were collected from whole saliva, and levels of Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Fusobacterium nucleatum were determined by PCR Invader technology. Detection of these species on oral mucosal and denture surfaces was performed by PCR. Fisher’s exact test was used for the statistical analysis. Cluster analysis was employed to investigate trends in the periodontopathic bacteria flora in each sampling area.

Results:  Detection rates of periodontopathic bacteria in whole saliva were lower under edentulous conditions than under dentulous conditions, except for A. actinomycetemcomitans and F. nucleatum (p < 0.01). Detection rate of F. nucleatum was the highest in all areas. A positive correlation was observed between DNA quantification of P. gingivalis and number of Candida species in saliva. Cluster analysis of the test species identified two clusters. Tongue‐coating status was associated with the detection rate of all periodontopathic bacteria investigated, and denture plaque status was associated with the detection rate of T. denticola and F. nucleatum.

Conclusion:  Results indicate the presence of periodontopathic bacteria under edentulous conditions and that the status of oral hygiene of the mucosal or denture surfaces affects colonisation by T. denticola and F. nucleatum.
THE CONCEPT OF EVIDENCE IN EVIDENCE‐BASED PRACTICE
Authors: Kvernbekk Tone
Published: September 2011

There exists a vast literature on evidence‐based practice (EBP) in education. The debate branches out in several directions, for example, what EBP entails for the nature of educational practice, what it entails for the teaching profession, what counts as use and abuse of evidence, and what educational research could or should contribute to a what works kind of practice. In this essay Tone Kvernbekk focuses on the fate of the concept of evidence in the debate, observing that the concept seems, by and large, to be missing from the debate. She argues that educational debates about EBP stand to gain in nuance and depth from employing philosophical insights about evidence. Kvernbekk develops this claim by discussing different conceptions of evidence and by inquiring into three aspects of the evidentiary relation: the meaning of “based,” underdetermination, and the relativization of evidence.
Physical Activity and Cervical Cancer Testing Among American Indian Women
Authors: Muus Kyle J. , Baker‐Demaray Twyla B. , Bogart T. Andy , Duncan Glen E. , Jacobsen Clemma , Buchwald Dedra S. , Henderson Jeffrey A.
Published: September 2011

Purpose: Studies have shown that women who engage in high levels of physical activity have higher rates of cancer screening, including Papanicalaou (Pap) tests. Because American Indian (AI) women are at high risk for cervical cancer morbidity and mortality, we examined Pap screening prevalence and assessed whether physical activity was associated with screening adherence among AI women from 2 culturally distinct regions in the Northern Plains and the Southwest.

Methods: A total of 1,979 AI women at least 18 years of age participating in a cross‐sectional cohort study reported whether they received a Pap test within the previous 3 years. Physical activity level was expressed as total metabolic equivalent (MET) scores and grouped into quartiles. We used binary logistic regression to model the association of Pap testing and MET quartile, adjusting for demographic and health factors.

Findings: Overall, 60% of women received a Pap test within the previous 3 years. After controlling for covariates, increased physical activity was associated with higher odds of Pap screening (OR = 1.1 per increase in MET quartile; 95% CI = 1.1, 1.2).

Conclusions: This is the first study to examine physical activity patterns and receipt of cancer screening in AIs. While recent Pap testing was more common among physically active AI women, prevalence was still quite low in all subgroups. Efforts are needed to increase awareness of the importance of cervical cancer screening among AI women.
Comparative Analysis of the Chemical Composition and Antioxidant Activity of Red (Psidium cattleianum) and Yellow (Psidium cattleianum var. lucidum) Strawberry Guava Fruit
Authors: Biegelmeyer Renata , Andrade Juliana Maria Mello , Aboy Ana Lúcia , Apel Miriam Anders , Dresch Roger Remy , Marin Rafaela , Raseira Maria do Carmo Bassols , Henriques Amélia Teresinha
Published: September 2011

Abstract:  Strawberry guava (Psidium cattleianum Sabine) is a native fruit of Brazil widely consumed fresh and used in the food industry. In this context, the present study deals with the chemical characterization and the antioxidant activity of the red (Psidium cattleianum) and yellow (P. cattleianum var. lucidum Hort.) strawberry guava fruits, cultivars Irapuã and Ya‐Cy, respectively. Knowledge of chemical composition is fundamental to human nutrition, contributing to the quality of foods. Phenolic compounds in both fruits were analyzed by HPLC–DAD and the total flavonoid content was determined by the Folin–Ciocalteu assay. The antioxidant activity was evaluated by the total reactive antioxidant (TRAP) method. Psidium cattleianum presented a higher content of polyphenolic compounds than P. cattleianum var. lucidum (501.33 and 292.03 mg/100 g, respectively), with hyperoside being one of the major flavonoids identified for both cultivars. In addition to flavonoids, P. cattleianum presented an anthocyanin, identified as cyanidin. The antioxidant activity varied in a concentration‐dependent manner for both strawberry guava species. The volatile oils in fruits and fatty acids in seeds were quantified by GC‐EM. The analysis of the essential oil of yellow strawberry guava was compared with a previous study on the red cultivar, revealing β‐caryophyllene as the main component in both oils. The fatty acid composition was also quite similar and was especially characterized by the presence of unsaturated fatty acids (86.25% and 76%, respectively), among which linoleic acid as the most abundant.

Practical Application:  In this study, the chemical characterization and the antioxidant activity of the red (Psidium cattleianum) and yellow (P. cattleianum var. lucidum Hort.) strawberry guava fruits were investigated. This is important for potential application of strawberry guava as functional food. Moreover, it may be the experimental basis for further development and use in food industry.
Effect of Grape Pomace Extracts Obtained from Different Grape Varieties on Microbial Quality of Beef Patty
Authors: Sagdic Osman , Ozturk Ismet , Yilmaz Mustafa Tahsin , Yetim Hasan
Published: September 2011

Abstract:  Grape pomace extracts were obtained from 5 different grape varieties grown in Turkey. The extracts were concentrated to obtain crude extracts; and incorporated into beef patties at 0% (Control), 1%, 2%, 5%, and 10% concentrations to test their antimicrobial effects in different storage periods (first, 12, 24, and 48 h). The numbers of microorganism were generally decreased by the extract concentration during the storage period. All the microorganisms tested were inhibited by the extract concentration of 10% in all the storage periods. Furthermore, the foodborne pathogens including Enterobacteriaceae and coliform bacteria, and the spoilage microorganisms including yeasts and moulds and lipolytic bacteria were also inhibited by 5% of Emir, Gamay, and Kalecik Karasi varieties in beef patties. Considering the results, the extracts of grape pomaces might be a good choice in the microbial shelf life extension of the food products as well as inhibiting the food pathogens as the case of beef patties.

Practical Application:  Grape pomace consists of seeds, skins, and stems, and an important by‐product that is well known to be the rich source of phenolic compounds, both flavonoids and non‐flavonoids. These substances have considerable beneficial effects on human health. The use of natural antimicrobial compounds, like plant extracts of herbs and spices for the preservation of foods has been very popular issue because of their antimicrobial activity. Therefore, grape pomace should be added into some food formulations to benefit from their protective effects. In this respect, this study reports the effect of addition of grape pomace extracts obtained from different grape varieties on microbial quality of beef patty. The results obtained in this study may be useful for food industry, which has recently tended to use natural antimicrobial sources in place of synthetic preservatives to prevent microbial spoilage.
Thermal Denaturation of Tilapia Myosin and Its Subunits as Affected by Constantly Increasing Temperature
Authors: Reed Zachary Harold , Guilford William , Park Jae Won
Published: September 2011

Abstract:  Purified tilapia myosin was digested with α‐chymotrypsin and purified to obtain heavy meromyosin (HMM) and light meromyosin (LMM). Biochemical properties of tilapia myosin, HMM, and LMM were characterized. Surface hydrophobicity (So) showed an increase for myosin and HMM between 30 and 40 °C and reached a plateau at 70 °C. LMM, in a small magnitude, also showed a continuous increase to 70 °C. Total sulfhydryl content (TSH) demonstrated that the SH residue content of HMM was nearly double that of LMM. Surface reactive sulfhydryl groups (SRSH) for myosin and HMM were relatively unchanged from 10 to 30 °C but increased from 30 to 50 °C. The exposure of buried hydrophobic and sulfhydryl groups of myosin and HMM increased as the myosin and HMM were constantly heated. However, the TSH and SRSH results indicated that the stability of LMM was likely due to its α‐helix conformation. Reducing and nonreducing sodium dodecylsulfate‐polyacryamide gel electrophoresis helped to understand the role of disulfide bonds in thermal aggregation of tilapia myosin, HMM, and LMM
Partial Replacement of Pork Back‐Fat by Vegetable Oils in Burger Patties: Effect on Oxidative Stability and Texture and Color Changes during Cooking and Chilled Storage
Authors: Rodríguez‐Carpena J.G. , Morcuende D. , Estévez M.
Published: September 2011

Abstract:  The present study was aimed to examine the impact of partial back‐fat replacement (50%) by avocado (A), sunflower (S), and olive (O) oil on the chemical composition, oxidative stability, color, and texture of porcine burger patties (10% fat) subjected to oven cooking (170 °C/18 min) and chilling (+ 4 °C/15 d). The addition of vegetable oils caused a significant reduction of saturated fatty acids and a concomitant enrichment in unsaturated fatty acids. The incorporation of vegetable oils to porcine patties caused a significant reduction of TBARS formed as a result of cooking and the subsequent chilling. The usage of vegetable oils as back‐fat replacers had no impact on the formation of protein carbonyls. Porcine patties with A‐ and O‐patties displayed a more favorable ratio between volatiles contributing to rancidity and those contributing pleasant odor notes. Treated and control patties underwent similar discoloration during processing. The usage of vegetable oils and particularly, avocado and olive oils, as back‐fat replacers, could be an interesting strategy to improve the nutritional and technological properties of porcine patties.

Practical Application:  The present study highlights the potential nutritional and technological benefits of replacing animal fat by vegetable oils in porcine patties subjected to cooking and chilling. The industrial application of vegetable oils in processed meat products would meet the current consumers’ interest towards healthier food products. In addition, the usage of avocado oil would contribute to boost the avocado industry by providing an additional value to a by‐product of great biological significance.
Differences in genetic variability between two ecotypes of the endangered myrmecophilous butterfly Phengaris (=Maculinea) alcon– the setting of conservation priorities
Authors: SIELEZNIEW MARCIN , RUTKOWSKI ROBERT , PONIKWICKA‐TYSZKO DONATA , RATKIEWICZ MIROSŁAW , DZIEKAŃSKA IZABELA , ŠVITRA GIEDRIUS
Published: September 2011

Abstract.  1. The endangered butterfly Phengaris alcon exists in two ecotypes (P. ‘alcon’ and P. ‘rebeli’), which inhabit contrasting biotopes (wet and warm/dry grasslands respectively) and use different larval food plants. The initially flower‐bud‐feeding caterpillars complete their development as social parasites of Myrmica ants, and the specificity of these relationships shows geographical variation.

2. We studied the genetic structure of 16 populations (365 individuals) of both ecotypes in eastern Europe, sampling P. ‘rebeli’ in two disjunct areas in Lithuania and southern Poland, and P. ‘alcon’ on Polish localities between them. We analysed the cytochrome c oxidase subunit I (COI) mitochondrial gene, the EF1‐α nuclear gene and five polymorphic microsatellite loci.

3. All individuals shared an identical COI haplotype, which we hypothesise may be linked to a selective sweep associated with the presence of the Wolbachia B strain in all populations.

4. For nuclear markers, we did not find a clear pattern reflecting division into two putative ecotypes. However, ecotypes differed significantly in their genetic variability, i.e., the P. ‘rebeli’ ecotype was less polymorphic, and its populations were much more differentiated (FST: 0.632 for EF1‐α and 0.504 for microsatellites) than the P. ‘alcon’ ecotype (0.177 and 0.082, respectively).

5. Our microsatellite data suggest that all populations of P. ‘alcon’ form a single clade but that P ‘rebeli’ can be split into either six or two clades. The former model would indicate many independent origins, especially in the mountainous areas of southern Poland. The latter, not mutually exclusive, grouping clearly reflects the use of different host ants.
A synthesis of qualitative research on overweight and obese people's views and experiences of weight management
Authors: Garip G. , Yardley L.
Published: September 2011

The effectiveness of existing weight management programmes may be improved by understanding overweight and obese people's perceptions of the reasons for successful and unsuccessful weight management. Many qualitative studies have investigated overweight and obese adults' experiences with weight management. This paper presents findings of a meta‐ethnography that synthesized 17 qualitative studies of overweight and obese adults' weight management experiences, principally in the context of behavioural weight management programmes. Twelve themes were derived describing factors that overweight and obese people identify as relevant to weight management: health concerns, expectations towards weight management, attributions for weight gain, psychological barriers, psychological facilitators, self‐perception and body image, stigmatization, socio‐cultural factors, environmental barriers, environmental facilitators, experiences with weight management programmes and positive outcomes of programme participation. Interventions that address all of the modifiable factors identified in this review are likely to appear credible to participants and will engage with the intra‐ and extra‐individual factors that they perceive as affecting their weight management efforts.
Methods for co-culturing tumour and endothelial cells: systems and their applications
Authors: van Moorst Mallory , Dass Crispin R
Published: September 2011

Objectives

The high levels of morbidity and mortality associated with cancer can be attributed to two main processes; the tumour's ability to rapidly proliferate and the process of metastasis. These key processes are facilitated by tumour-induced angiogenesis, which causes existing blood vessels to branch off and actively grow towards the tumour providing it with the nutrients and oxygen required for growth and the avenue through which it can metastasise to invade other tissues. This process involves complex interactions between tumour and endothelial cells and is at the forefront of modern biomedical research as anti-angiogenic therapies may hold the key to preventing tumour growth and spread. This review looks at modern co-culture systems used in the study of the tumour–endothelial cell relationship highlighting the applications and weaknesses of each model and analysing their uses in various tumour–endothelial cell investigations.

Key findings

The tumour–endothelial cell relationship can be studied in vitro using co-culture systems that involve growing endothelial and tumour cells together so that the effects of dynamic interaction (either by direct cell contact or molecular cross-talk) can be monitored. These co-culture assays are quite accurate indicators of in-vivo growth and therefore allow more effective trialling of therapeutic treatments.

Conclusions

The application of co-culture systems are of fundamental importance to understanding the tumour–endothelial cell relationship as they offer a method of in-vitro testing that is highly indicative of in-vivo processes. Co-cultures allow accurate testing, which is cost effective and therefore can be utilised in almost all laboratories, is reproducible and technically simple to perform and most importantly has biological relevancy. The importance of this form of testing is such that it warrants further investment of both time and money to enhance the methodology such as to eliminate some of the levels of variability.
Processing information related to centrally initiated locomotor and voluntary movements by feline spinocerebellar neurones
Authors: Jankowska E. , Nilsson E. , Hammar I.
Published: September 2011

Non‐technical summary  For the correct execution of centrally initiated movements, it is vital that the cerebellum receives continuous feedback from the spinal cord. We recently demonstrated that a population of spinocerebellar neurones provides the cerebellum with feedback on the likely outcome of descending commands relayed via reticulospinal neurones. We now demonstrate that the same spinocerebellar neurones provide information on the likely outcome of commands from the corticospinal tract (pyramidal tract) neurones as well as from the mesencephalic locomotor region. The results indicate that both voluntary motor actions and those related to locomotion are relayed by reticulospinal neurones and are monitored by the same population of spinocerebellar neurons, which may thereby provide the brain with information necessary for avoiding errors in issuing movements.
Dynamic Feature Monitoring Technique Applied to Thin Film Deposition Processes in an Industrial PECVD Tool
Authors: Bleakie Alexander , Djurdjanovic Dragan
Published: September 2011

In semiconductor fabrication processes, reliable feature extraction and condition monitoring is critical to understanding equipment degradation and implementing the proper maintenance decisions. This paper presents an integrated feature extraction and equipment monitoring approach based on standard built-in sensors from a modern 300mm-technology industrial Plasma Enhanced Chemical Vapor Deposition (PECVD) tool. Linear Discriminant Analysis was utilized to determine the set of dynamic features that are the most sensitive to different tool conditions brought about by chamber cleaning. Gaussian Mixture Models of the dynamic feature distributions were used to statistically quantify changes of these features as the condition of the tool changed. Data was collected in the facilities of a well-known microelectronics manufacturer from a PECVD tool used for depositing various thin films on silicon wafers, which is one of the key steps in semiconductor manufacturing. Dynamic features coming from the radio frequency (RF) plasma power generator, matching capacitors, pedestal temperature, and chamber temperature sensors were shown to consistently have significant statistical changes as a consequence of repeated cleaning cycles, indicating physical connections to the chamber condition.
Application of Topology Optimization in Product Design and Manufacturing
Authors: Ragai Ihab , Tempelman Harry , Kirby David
Published: September 2011

This paper deals with the utilization of topology optimization in the design process. Topology optimization is considered the most challenging task in the structural design optimization problems because the general layout of the structure is not known; however, implementing it in the conceptual design stage has proven to reduce the cost and development time. In this paper, the design process is briefly discussed emphasizing the use of topology optimization in the conceptual design stage. Also, the mathematical formulation for topology optimization with material density contours is presented. Furthermore, two industrial case studies, related to off-road mining and construction trucks, are discussed where the use of topology optimization has proven to dramatically improve an existing design and significantly decrease the development time of a new design.
Investigation of Corrosion Processing for Ti-6Al-4V in Hydrofluoric-Nitric Acid System
Authors: Lin C. , Hong X. P.
Published: September 2011

Corrosion processing is an effective way to solve difficult machining of titanium alloy. It can be applied for reducing weight, machining complex shape and fine structure. In this paper, the effects of the bath constituents and operation conditions on corrosion processing rate and surface quality for Ti-6Al-4V were investigated. Corrosion processing rate depends upon hydrofluoric acid concentration, the volume ratio of nitric acid to hydrofluoric acid, temperature. Nitric acid can promote the surface passivation and reduce surface roughness. The surfactant plays a dual role of surface finish improvement and acid fog suppression. During the period of processing, oxide film on the surface is dissolved initially, and there is the faster processing rate. Surface passivation occurs with the extension of time, decreasing processing rate. Finally corrosion processing rate trends to be stable when the growth of passive film and dissolution of the substrate achieve dynamic balance.
Experimental Study of Micro Abrasive Tool Making by Electroplating
Authors: Dabholkar Anuj , Sundaram M. M.
Published: September 2011

Accurate and precise micro abrasive tools are essential for the micromachining of highly complex features in a wide variety of engineering materials including metals and ceramics. With existing abrasive coating techniques such as sol-gel method, chemical vapor deposition, physical vapor deposition, and composite electroforming, it is difficult to control the aggregation tendency of abrasive grains. This work evaluates the feasibility of implementing electroplating principles to fabricate a micro abrasive tool by co-deposition of nickel and micro diamond powder over a tungsten substrate. In this work, a tungsten rod of diameter 500 μm was deposited with 2–4 μm diamond abrasive grains using nickel as a binder. Scanning Electron Microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) studies reveal that more uniform coating is obtained with multilayer coating of micro diamond abrasive by electroplating. The coating process mechanism is discussed.
A Preliminary Study on Machinability of Polymethylmethacrylate (PMMA)/Multi-Walled Carbon Nanotube (MWCNT) Nanocomposites in Focused Ion Beam Micromachining
Authors: Li Pengfei , Xue Wei , Kim Dave Dae-Wook , Park Young-Bin
Published: September 2011

This experimental study investigated the machinability of polymethylmethacrylate (PMMA)/multi-walled carbon nanotube (MWCNT) nanocomposites with 20 wt% MWCNTs in focused ion beam (FIB) micromachining. PMMA/MWCNT nanocomposites were fabricated using a solution casting method, in which PMMA and MWCNTs were dispersed in a solvent by ultrasonication. Microscale rectangular pockets were created on the PMMA/MWCNT nanocomposites to study the material removal mechanism in FIB. Effects of FIB input current and the ion beam overlap parameter (overlap %) on the material removal rate and geometric accuracy were studied. It was observed that the material removal rate increased with increasing input current and decreasing overlap %. Soft lithography was used to translate the ion-milled pockets on PMMA/MWCNT nanocomposites into microscale posts on polydimethylsiloxane (PDMS) for accurate measurement of the pocket geometries. A Scanning Electron Microscope (SEM) was used to investigate the characteristics of the micromachined features, nanocomposite surfaces, and replicated PDMS patterns. Our results demonstrated an effective method to produce microscale patterns on MWCNT-based nanocomposites.
Intelligent Metal-Forming Simulation
Authors: Joun Man-Soo , Lee Min-Cheol , Eom Jae-Gun
Published: September 2011

In this paper, the basic concepts and requirements of intelligent metal-forming simulation are presented. A general-purpose metal-forming simulator AFDEX developed to meet the requirements is then discussed, with emphasis on its intelligence. The simulator is based on an adaptive and optimal mesh-generation technique and includes many intelligent, application-oriented special functions, which not only enhance solution accuracy but also minimize user intervention during a metal-forming simulation. Characteristics and typical applications of the simulator are described.
Development of a New Vibrator for Elliptical Vibration Texturing
Authors: Guo Ping , Ehmann Kornel F.
Published: September 2011

Inspired by the idea of vibro-mechanical texturing, which adds a tertiary motion to the tool tip in the conventional turning process, and the elliptical vibration cutting process, which adds vibrations both in the cutting direction and feed direction, this paper proposes a new design for an ultrasonic vibrator for the elliptical vibration texturing process. The elliptical locus lies in the plane that is defined by the cutting and the radial directions. The device could be easily adapted for elliptical cutting applications by changing the orientation of the tool tip. The vibrator works in the resonant mode, with in-phase and anti-phase vibration modes at a nearly identical natural frequency. Simulations and experiments have been carried out to study and verify different vibration modes of the system. Different design parameters have been analyzed to control the elliptical trajectory of the tool tip. A set of preliminary experimental result of elliptical vibration texturing is also provided.
Energy Consumption Reduction in Serial Production Lines via Controlled Machine Startup
Authors: Chen Guorong , Zhang Liang , Arinez Jorge , Biller Stephan
Published: September 2011

Research efforts for energy consumption reduction in manufacturing systems have been centered at technology and process innovation. These projects, however, often involve major capital investment of new equipment and material. In this paper, we explore energy saving opportunities through improvement in factory floor operations. Specifically, in the framework of Bernoulli serial lines, we consider production systems with stripping operations. In such systems, the in-process buffers have to be depleted at the end of each shift to avoid quality deterioration during off-shift periods. Transient analysis of the systems are carried out and formulas to calculate the performance measures are derived. In addition, we investigate the effect of machine startup schedule on the system performances and develop optimal startup schedule which, as shown in the paper, can lead to significant improvement in energy utilization efficiency.
Effect of Film Formation Method and Annealing on Crystallinity of Poly(L-Lactic Acid) Films
Authors: Hsu Shan-Ting , Yao Y. Lawrence
Published: September 2011

Poly(L-lactic acid) (PLLA) has been shown to have potential medical usage such as in drug delivery because it can degrade into bioabsorbable products in physiological environments, and its degradation is affected by crystallinity. In this paper, the effect of film formation method and annealing on the crystallinity of PLLA are investigated. The films are made through solvent casting and spin coating methods, and subsequent annealing is conducted. The resulting crystalline morphology, structure, conformation, and intermolecular interaction are examined using optical microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. It is observed that solvent casting produces category 1 spherulites while annealed spin coated films leads to spherulites of category 2. Distinct lamellar structures and intermolecular interactions in the two kinds of films have been shown. The results enable better understanding of the crystallinity in PLLA, which is essential for its drug delivery application.
Predicting the High Speed Cutting Process of Titanium Alloy by Finite Element Method
Authors: Zhang Xiangqin , Zhang Xueping , Srivastava A. K.
Published: September 2011

To predict the cutting forces and cutting temperatures accurately in high speed dry cutting Ti-6Al-4V alloy, a Finite Element (FE) model is established based on ABAQUS. The tool-chip-work friction coefficients are calculated analytically using the measured cutting forces and chip morphology parameter obtained by conducting the orthogonal (2-D) machining tests. It reveals that the friction coefficients between tool-work are 3∼7 times larger than that between tool-chip, and the friction coefficients of tool-chip-work vary with feed rates. The analysis provides a better reference for the tool-work-chip friction coefficients than that given by literature empirically regardless of machining conditions. The FE model is capable of effectively simulating the high speed dry cutting process of Ti-6Al-4V alloy based on the modified Johnson-Cook model and tool-work-chip friction coefficients obtained analytically. The FE model is further validated in terms of predicted forces and the chip morphology. The predicted cutting force, thrust force and resultant force by the FE model agree well with the experimentally measured forces. The errors in terms of the predicted average value of chip pitch and the distance between chip valley and chip peak are smaller. The FE model further predicts the cutting temperature and residual stresses during high speed dry cutting of Ti-6Al-4V alloy. The maximum tool temperatures exist along the round tool edge, and the residual stress profiles along the machined surface are hook-shaped regardless of machining conditions.
Dislocation Density-Based Grain Refinement Modeling of Orthogonal Cutting of Commercially Pure Titanium
Authors: Ding Hongtao , Shin Yung C.
Published: September 2011

Recently, machining has been exploited as a means for producing ultra-fine grained (UFG) and nanocrystalline microstructures for various metal materials, such as aluminum alloys, copper, stainless steel, titanium and nickel-based super alloys, etc. However, no predictive, analytical or numerical work has ever been presented to quantitatively predict the change of grain sizes during machining. In this paper, a dislocation density-based viscoplastic model is adapted for modeling the grain size refinement mechanism during machining by means of a finite element based numerical framework. A novel Coupled Eulerian-Lagrangian (CEL) finite element model embedded with the dislocation density subroutine is developed to model the severe plastic deformation and grain refinement during a steady-state cutting process. The orthogonal cutting tests of a commercially pure titanium (CP Ti) material are simulated in order to assess the validity of the numerical solution through comparison with experiments. The dislocation density-based material model is calibrated to reproduce the observed material constitutive mechanical behavior of CP Ti under various strains, strain rates and temperatures in the cutting process. It is shown that the developed model captures the essential features of the material mechanical behavior and predicts a grain size of 100–160 nm in the chips of CP Ti at a cutting speed of 10 mm/s.
Hybrid Manufacturing of Deep Holes With Small Diameters
Authors: Biermann Dirk , Heilmann Markus
Published: September 2011

Bore holes with a high length-to-diameter (l/D)-ratio and small diameters are needed in various industries. Examples are the downsizing of components for medical and biomedical products or for fuel injection in automotive industry due to the increase of injection pressure. For the production of deep holes with very small diameters an adapted process design is necessary, especially when the conditions at the begin of the deep hole drilling process are unfavorable. In these applications, a hybrid process consisting of a laser pre-drilling and a single-lip deep hole drilling can shorten the process chain in machining components with non-planar surfaces, or can reduce tool wear in machining case-hardened materials. In this research, the combination of laser and single-lip drilling processes for the machining of workpieces with non-planar surfaces was realized and investigated for the very first time.
Evaluation of a Reverse Oscillatory Flow Microreactor Design for the Synthesis of Uniformly-Sized Nanoparticles
Authors: Peterson Daniel A. , Garrison Anna E. , Paul Brian K.
Published: September 2011

Computational fluid dynamics is used to refine the operating parameters of a Reverse Oscillatory Flow (ROF) microreaction system for the synthesis of uniformly-sized nanoparticles. The ROF mixing system uses highly advective flow regions to achieve high quality mixing over short mixing lengths. The mixing system is further enhanced by sinusoidal inlet flow conditions which create plugs having reduced diffusional lengths. Flow conditions leading to plug creation were found to be chiefly responsible for shorter mixing times. Residence time distributions (of simulated inert particles) were found to decrease with increasing pump displacement. It is expected that these conditions will lead to smaller particle size distributions. Mixing quality and residence time distribution are not captured well by Reynolds or Strouhal numbers; however the maximum inlet Reynolds number does correlate well with mixing time trends. Implications for flow conditions are discussed.
A Study on Machining and Environmental Characteristics of Micro-Drilling Process Using Nanofluid Minimum Quantity Lubrication
Authors: Nam Jung Soo , Lee Pil-Ho , Lee Sang Won
Published: September 2011

This paper presents two basic experimental studies of a micro-drilling process with nanofluid minimum quantity lubrication (MQL) in terms of machining and environmental characteristics. By using a miniaturized desktop machine tool system, a series of micro drilling experiments were conducted in the cases of dry, compressed air and nanofluid MQL. The experimental results imply that nanofluid MQL significantly reduces the adhesion of chips when compared with the cases of dry and compressed air micro-drilling. As a result, it is observed that the magnitudes of average drilling torque and thrust force are decreased and the tool life of micro drills is extended in the case of nanofluid MQL micro-drilling process. In addition, the empirical study on environmental characteristics of MQL micro-drilling process is conducted by measuring MQL oil mist with the oil sampling method. The results show that remaining MQL oil mist is tiny enough not to have a detrimental effect on human health.
Surface Texturing of Metals by Cathode Spots of Atmospheric Arc
Authors: Sarrafi Rouzbeh , Asgharifar Mehdi , Kovacevic Radovan
Published: September 2011

This paper investigates the application of atmospheric arc (the same arc that is used for welding) for surface texturing of aluminum alloy in micro scale. This research shows that micro-texturing of metallic surfaces is feasible with an arc-based, inexpensive, environment-friendly method. In this paper, fundamental phenomena occurring during surface texturing process using cathode spots of arc are introduced. The surface texturing process is experimentally studied using surface microscopy and high-speed real-time monitoring by a machine-vision system. The advantages of the process and the potential applications are discussed.
Shigella flexneri
Infection Generates the Lipid PI5P to Alter Endocytosis and Prevent Termination of EGFR Signaling
Authors: Ramel Damien , Lagarrigue Frédéric , Pons Véronique , Mounier Joëlle , Dupuis-Coronas Sophie , Chicanne Gaëtan , Sansonetti Philippe J. , Gaits-Iacovoni Frédérique , Tronchère Hélène , Payrastre Bernard
Published: September 2011

Shigella
keeps infected cells alive by preventing the lysosomal trafficking and degradation of an activated growth factor receptor.
Contribution of Resistance-Nodulation-Division Efflux Pump Operon
smeU1-V-W-U2-X
to Multidrug Resistance of Stenotrophomonas maltophilia
Authors: Chen Chao-Hsien , Huang Chiang-Ching , Chung Tsao-Chuen , Hu Rouh-Mei , Huang Yi-Wei , Yang Tsuey-Ching
Published: September 2011

KJ09C, a multidrug-resistant mutant of
Stenotrophomonas maltophilia
KJ, was generated by
in vitro
selection with chloramphenicol. The multidrug-resistant phenotype of KJ09C was attributed to overexpression of a resistance nodulation division (RND)-type efflux system encoded by an operon consisting of five genes:
smeU1
,
smeV
,
smeW
,
smeU2
, and
smeX
. Proteins encoded by
smeV
,
smeW
, and
smeX
were similar to the membrane fusion protein, RND transporter, and outer membrane protein, respectively, of known RND-type systems. The proteins encoded by
smeU1
and
smeU2
were found to belong to the family of short-chain dehydrogenases/reductases. Mutant KJ09C exhibited increased resistance to chloramphenicol, quinolones, and tetracyclines and susceptibility to aminoglycosides; susceptibility to β-lactams and erythromycin was not affected. The expression of the
smeU1-V-W-U2-X
operon was regulated by the divergently transcribed LysR-type regulator gene
smeRv
. Overexpression of the SmeVWX pump contributed to the acquired resistance to chloramphenicol, quinolones, and tetracyclines. Inactivation of
smeV
and
smeW
completely abolished the activity of the SmeVWX pump, whereas inactivation of
smeX
alone decreased the activity of the SmeVWX pump. The enhanced aminoglycoside susceptibility observed in KJ09C resulted from SmeX overexpression.
Impact of
fgd1
and
ddn
Diversity in Mycobacterium tuberculosis Complex on
In Vitro
Susceptibility to PA-824
Authors: Feuerriegel Silke , Köser Claudio U. , Baù Davide , Rüsch-Gerdes Sabine , Summers David K. , Archer John A. C. , Marti-Renom Marc A. , Niemann Stefan
Published: September 2011

PA-824 is a promising drug candidate for the treatment of tuberculosis (TB). It is in phase II clinical trials as part of the first newly designed regimen containing multiple novel antituberculosis drugs (PA-824 in combination with moxifloxacin and pyrazinamide). However, given that the genes involved in resistance against PA-824 are not fully conserved in the
Mycobacterium tuberculosis
complex (MTBC), this regimen might not be equally effective against different MTBC genotypes. To investigate this question, we sequenced two PA-824 resistance genes (
fgd1
[
Rv0407
] and
ddn
[
Rv3547
]) in 65 MTBC strains representing major phylogenetic lineages. The MICs of representative strains were determined using the modified proportion method in the Bactec MGIT 960 system. Our analysis revealed single-nucleotide polymorphisms in both genes that were specific either for several genotypes or for individual strains, yet none of these mutations significantly affected the PA-824 MICs (≤0.25 μg/ml). These results were supported by
in silico
modeling of the mutations identified in Fgd1. In contrast, “
Mycobacterium canettii
” strains displayed a higher MIC of 8 μg/ml. In conclusion, we found a large genetic diversity in PA-824 resistance genes that did not lead to elevated PA-824 MICs. In contrast,
M. canettii
strains had MICs that were above the plasma concentrations of PA-824 documented so far in clinical trials. As
M. canettii
is also intrinsically resistant against pyrazinamide, new regimens containing PA-824 and pyrazinamide might not be effective in treating
M. canettii
infections. This finding has implications for the design of multiple ongoing clinical trials.
Dermacentor andersoni Transmission of Francisella tularensis subsp. novicida Reflects Bacterial Colonization, Dissemination, and Replication Coordinated with Tick Feeding
Authors: Reif Kathryn E. , Palmer Guy H. , Ueti Massaro W. , Scoles Glen A. , Margolis J. J. , Monack D. M. , Noh Susan M.
Published: September 2011

Ticks serve as biological vectors for a wide variety of bacterial pathogens which must be able to efficiently colonize specific tick tissues prior to transmission. The bacterial determinants of tick colonization are largely unknown, a knowledge gap attributed in large part to the paucity of tools to genetically manipulate these pathogens. In this study, we demonstrated that
Francisella tularensis
subsp.
novicida
, for which a complete two-allele transposon mutant library has been constructed, initially infects the midguts of 100% of acquisition-fed
Dermacentor andersoni
nymphs, with stable colonization and replication during a subsequent molt. Increased dissemination to and marked replication within the salivary gland was closely linked to a second (transmission) feed and culminated in secretion of bacteria into the saliva and successful transmission. Simultaneous testing of multiple mutants resulted in total bacterial levels similar to those observed for single mutants. However, there was evidence of a bottleneck during colonization, resulting in a founder effect in which the most successful mutant varied when comparing individual ticks. Thus, it is essential to assess mutant success at the level of the tick population rather than in individual ticks. The ability of
F. tularensis
subsp.
novicida
to recapitulate the key physiological events by which bacteria colonize and are transmitted by ixodid ticks provides a new genome-wide approach to identify the required pathogen molecules and pathways. The identification of specific genes and, more importantly, conserved pathways that function at the tick-pathogen interface will accelerate the development of new methods to block transmission.
ON SURFACE WAVES IN A FINITELY DEFORMED MAGNETOELASTIC HALF-SPACE
Authors: SAXENA P. , OGDEN R. W.
Published: September 2011

Rayleigh-type surface waves propagating in an incompressible isotropic half-space of nonconducting magnetoelastic material are studied for a half-space subjected to a finite pure homogeneous strain and a uniform magnetic field. First, the equations and boundary conditions governing linearized incremental motions superimposed on an initial motion and underlying electromagnetic field are derived and then specialized to the quasimagnetostatic approximation. The magnetoelastic material properties are characterized in terms of a "total" isotropic energy density function that depends on both the deformation and a Lagrangian measure of the magnetic induction. The problem of surface wave propagation is then analyzed for different directions of the initial magnetic field and for a simple constitutive model of a magnetoelastic material in order to evaluate the combined effect of the finite deformation and magnetic field on the surface wave speed. It is found that a magnetic field in the considered (sagittal) plane in general destabilizes the material compared with the situation in the absence of a magnetic field, and a magnetic field applied in the direction of wave propagation is more destabilizing than that applied perpendicular to it.
AN EXPERIMENTAL STUDY OF SEMICONDUCTOR PROCESS CHILLER USING INDIVIDUAL AND DUAL COMPRESSOR METHOD
Authors: CHA DONG AN , KWON OH KYUNG , OH MYUNG DO
Published: September 2011

Excessive heat occurs during the semiconductor manufacturing process. Thus, precise control of temperature is required to maintain constant chamber temperature and also wafer temperature in the chamber. Compared to an industrial chiller, a semiconductor chiller's power consumption is very high due to its continuous operation for a year. Considering the high power consumption, it is necessary to develop an energy efficient chiller by optimizing operation control. Therefore, in this study, a semiconductor chiller is experimentally investigated to suggest an energy-saving direction by conducting load change, controlling the temperature's rise and fall and controlled precision experiments. The experimental study shows how the cooling capacity of new model chiller rises over 30% compared to the old model chiller. The time and power consumption in the temperature rising experiments are 43 min and 8.4 kWh, respectively. The control precision is the same as ± 1°C, at 0°C, in any case. However, it appears that the new model channel's control precision improves to ± 0.5°C when the setting temperature is over 30°C.
When the museum goes native
Authors: Smith Rachel Charlotte , Iversen Ole Sejer
Published: September 2011

On Heritage aims to offer and promote a rich discussion at the intersection of art, performance, and culture that expands the boundaries of HCI while broadening our understanding of how things of the past come to matter in the present.

Elisa Giaccardi, Editor
SIMROT
Authors: Elmokashfi Ahmed , Kvalbein Amund , Dovrolis Constantine
Published: September 2011

BGP plays a crucial role in the global communications infrastructure, and there is a strong need for tools that can be used for analyzing its performance under different scenarios. The size and complexity of the inter-domain routing system often makes simulation the only viable method for such studies. This work addresses the lack of a comprehensive toolbox to simulate BGP. It proposes a flexible topology generator that produces AS-level graphs which are annotated with business relationships. The second component of the toolbox is a light-weight BGP simulator that is capable of capturing routing dynamics, while scaling to network sizes of thousands of nodes. We employ our framework to investigate a set of what-if questions concerning the impact of different topology parameters on BGP dynamics. This investigation shows how our proposed framework can help in gaining important insights on inter-domain routing dynamics.