bluuebunny/crossref_metadata_2025 huggingface dataset:
A breakthrough in lupin biotechnology: prolific protocolonisation in recalcitrant white lupin (Lupinus albus) triggered by bovine serum albumin
Authors: Sinha A. , Caligari P.D.S.
Published: September 2008

Six nutrient formulations were studied for their efficacy in inducing mitosis in white lupin seedling cotyledon protoplasts of which the formulations of Schäfer‐Menuhr & Stürmer (AS) and Kao (K8p) were found to be superior over the other four when supplemented with 6‐benzylaminopurine and α‐naphthaleneacetic acid (α‐NAA). An ultrafiltration treatment of K8p increased mitotic frequency by 130% when compared with the untreated control. Medium enrichment with 0.2% bovine serum albumin (BSA) brought about a dramatic 1341% rise in protoplast division in comparison with BSA‐free medium but only when the enrichment was carried out in Kao and Michayluk (KM8p) background containing 2,4‐dichlorophenoxyacetic acid, α‐NAA and zeatin. A higher number of protocolonies (each proliferating from single protoplast following multiple divisions) were seen in 0.4% BSA. With this breakthrough in white lupin protoplast research, it is now possible to reproducibly obtain protocolonies that was hitherto not possible.
Using Nitrate to Quantify Quick Flow in a Karst Aquifer
Authors: Mahler Barbara J. , Garner Bradley D.
Published: September 2008

In karst aquifers, contaminated recharge can degrade spring water quality, but quantifying the rapid recharge (quick flow) component of spring flow is challenging because of its temporal variability. Here, we investigate the use of nitrate in a two‐endmember mixing model to quantify quick flow in Barton Springs, Austin, Texas. Historical nitrate data from recharging creeks and Barton Springs were evaluated to determine a representative nitrate concentration for the aquifer water endmember (1.5 mg/L) and the quick flow endmember (0.17 mg/L for nonstormflow conditions and 0.25 mg/L for stormflow conditions). Under nonstormflow conditions for 1990 to 2005, model results indicated that quick flow contributed from 0% to 55% of spring flow. The nitrate‐based two‐endmember model was applied to the response of Barton Springs to a storm and results compared to those produced using the same model with δ18O and specific conductance (SC) as tracers. Additionally, the mixing model was modified to allow endmember quick flow values to vary over time. Of the three tracers, nitrate appears to be the most advantageous because it is conservative and because the difference between the concentrations in the two endmembers is large relative to their variance. The δ18O‐based model was very sensitive to variability within the quick flow endmember, and SC was not conservative over the timescale of the storm response. We conclude that a nitrate‐based two‐endmember mixing model might provide a useful approach for quantifying the temporally variable quick flow component of spring flow in some karst systems.
An historical overview of selected rare ruminants in captivity
Authors: THOMAS WARREN D. , BARNES ROBERT , CROTTY MICHAEL , JONES MARVIN
Published: September 2008

In assessing the situation revealed by the survey, we concluded that in general when sufficient numbers of founders were available and attention paid to the animals general and specific needs, including preventative medicine, the captive populations have done reasonably well.

Is is obvious that some small groups, such as the small African antelope and the duikers, need highly specialised care and there is a great deal of work still to be done on their husbandry.

The mountain or alpine species have been fairly successful with the goats showing the greatest adaptability. We feel there are grounds for optimism for the future of such animals as the Rocky mountain goat, the Japanese serow and even the Blue sheep.

Of those species whose captive future is still in doubt, particularly those which are threatened in the wild, our researches indicate that concentrated efforts should be made to obtain sufficient founder stock to establish self‐sustaining populations as a hedge against total disaster in the wild. We felt that the evidence was strong that any of the ungulate species reviewed could be successfully maintained in captivity given the right circumstances.

Basically, the husbandry procedures of all the reporting zoos were similar, although, of course, each zoo had its own variations. In some cases these measurably affected the success of the animal population. In the last 20 to 25 years inter‐zoo co‐operation and sharing of information has greatly expanded. Nevertheless we would now urge that even more emphasis should be put on the exchange of information to provide each zoo with up‐ to‐date data which would ensure that all zoos are kept abreast with the 'state of the art. With such a spirit of co‐operation the prospect of managing species as total captive populations appears to be practical and promising.
Chronic inhibition of standing behaviour alters baroreceptor reflex function in rats
Authors: Waki H. , Katahira K. , Yamasaki M. , Katsuda S. , Shimizu T. , Maeda M.
Published: September 2008

Aim: To investigate whether daily orthostatic stress during development is an important factor affecting arterial baroreceptor reflex function, we examined the effect of chronic inhibition of upright standing behaviour on the baroreceptor reflex function in rats.

Methods: Upright standing behaviour was chronically inhibited during the developmental period between 3 and 8 weeks of age in Sprague–Dawley rats and heart rate (HR) and aortic nerve activity in response to increased and decreased mean arterial pressure (MAP) was measured after the treatment period.

Results: The baroreceptor cardiac gain in the rats grown without standing behaviour was significantly lower than the control rats grown in a normal commercial cage (1.0 ± 0.1 beats min−1 mmHg−1vs. 1.6 ± 0.2 beatsmin−1 mmHg−1,P < 0.05). The range of HR change in the MAP–HR functional curve was also lowered by chronic inhibition of orthostatic behaviour (56.2 ± 5.9 beats min−1) compared with that of the control rats (76.8 ± 6.9 beats min−1,P < 0.05). However the aortic afferent function remained normal after the treatment period, indicating that the attenuated baroreceptor reflex function may be due to other mechanisms involving functional alterations in the cardiovascular centres, efferents and/or peripheral organs. Body weight and adrenal weight were not affected by the inhibition of orthostatic behaviour, suggesting that the animals were not exposed to specific stress by this treatment.

Conclusion: These results indicate that active haemodynamic changes induced by orthostatic behaviour are an important factor for setting the basal level of reflex function during development. Moreover, our experimental model may be useful for studying mechanisms of attenuated baroreceptor reflex observed after exposure to a chronic inactive condition.
Tutorial on Computational Linguistic Phylogeny
Authors: Nichols Johanna , Warnow Tandy
Published: September 2008

Over the last 10 or more years, there has been a tremendous increase in the use of computational techniques (many of which come directly from biology) for estimating evolutionary histories (i.e., phylogenies) of languages. This tutorial surveys the different methods and different types of linguistic data that have been used to estimate phylogenies, explains the scientific and mathematical foundations of phylogenetic estimation, and presents methodologies for evaluating a phylogeny estimation method.
Language Ecology and Linguistic Diversity on the African Continent
Authors: Dimmendaal Gerrit J.
Published: September 2008

Africanists have been criticized by comparative linguists working on language families in other parts of the world for being lumpers. The present contribution reviews current views among specialists on genetic diversity on the African continent. In addition, some of the causal mechanisms behind this language diversity are investigated. More specifically, the role played by innovations in subsistence economies and climatological changes is discussed. Special emphasis, however, is put on attitudes towards the role of language as a marker of social identity and their effect on language diversity.
Historical Pragmatics
Authors: Jucker Andreas H.
Published: September 2008

In a broad, sociologically based view of pragmatics, historical pragmatics is a field of study that wants to understand the patterns of intentional human interaction (as determined by the conditions of society) of earlier periods, the historical developments of these patterns, and the general principles underlying such developments. It is based on an empirical study of historical data in all the diversity in which it has survived. Written texts are seen as communicative acts in their own right and they are taken to comprise a broad range of varieties of language that can be located on several different variability scales, such as the scale from the language of immediacy to the language of distance. The field of historical pragmatics can be split into subfields on the basis of the linguistic unit under investigation; from expressions to utterances, discourses, and discourse domains. Future work in historical pragmatics is expected to rely even more heavily on corpus‐linguistic methodologies and to increase the sophistication of such analyses, particularly in terms of pattern searches for functional elements and the inclusion of contextual features.
Functional Properties as Affected by Laboratory‐Scale Parboiling of Rough Rice and Brown Rice
Authors: Patindol J. , Newton J. , Wang Y.‐J.
Published: September 2008

ABSTRACT:  Rough rice (RR) is the conventional feedstock for parboiling. The use of brown rice (BR) instead of RR is gaining interest because it results in shorter processing time and lower energy requirement. This study compared the functional properties of milled parboiled rice under different parboiling conditions from RR and BR. Presoaked RR and BR from cultivars Bolivar, Cheniere, Dixiebelle, and Wells were parboiled under mild (20 min, 100 °C, 0 kPa) and severe (20 min, 120 °C, 98 kPa) laboratory‐scale conditions. Head rice yield improved on the RR and BR samples subjected to severe parboiling and was comparable to that of a commercially parboiled sample. Mild parboiling of BR resulted in lower head rice yields. Parboiling generally resulted in decreased head rice whiteness, decreased apparent amylose, increased total lipid, and sparingly changed protein content. Under the same parboiling conditions, the extent of starch gelatinization was higher for BR compared to RR as manifested by some distinct differences in pasting and thermal properties. The cooking characteristics (water uptake ratio, leached materials, and volumetric expansion) and cooked rice texture (hardness and stickiness) of RR and BR subjected to severe parboiling were fairly comparable. Differences in parboiled rice functional properties due to cultivar effect were evident.
Inactivation of Escherichia coli in a Tropical Fruit Smoothie by a Combination of Heat and Pulsed Electric Fields
Authors: Walkling‐Ribeiro M. , Noci F. , Cronin D.A. , Lyng J.G. , Morgan D.J.
Published: September 2008

ABSTRACT:  Moderate heat in combination with pulsed electric fields (PEF) was investigated as a potential alternative to thermal pasteurization of a tropical fruit smoothie based on pineapple, banana, and coconut milk, inoculated with Escherichia coli K12. The smoothie was heated from 25 °C to either 45 or 55 °C over 60 s and subsequently cooled to 10 °C. PEF was applied at electric field strengths of 24 and 34 kV/cm with specific energy inputs of 350, 500, and 650 kJ/L. Both processing technologies were combined using heat (45 or 55 °C) and the most effective set of PEF conditions. Bacterial inactivation was estimated on standard and NaCl‐supplemented tryptone soy agar (TSA) to enumerate sublethally injured cells. By increasing the temperature from 45 to 55 °C, a higher reduction in E. coli numbers (1 compared with 1.7 log10 colony forming units {CFU} per milliliter, P < 0.05) was achieved. Similarly, as the field strength was increased during stand‐alone PEF treatment from 24 to 34 kV/cm, a greater number of E. coli cells were inactivated (2.8 compared with 4.2 log10 CFU/mL, P < 0.05). An increase in heating temperature from 45 to 55 °C during a combined heat/PEF hurdle approach induced a higher inactivation (5.1 compared with 6.9 log10 CFU/mL, respectively {P < 0.05}) with the latter value comparable to the bacterial reduction of 6.3 log10 CFU/mL (P≥ 0.05) achieved by thermal pasteurization (72 °C, 15 s). A reversed hurdle processing sequence did not affect bacterial inactivation (P≥ 0.05). No differences were observed (P≥ 0.05) between the bacterial counts estimated on nonselective and selective TSA, suggesting that sublethal cell injury did not occur during single PEF treatments or combined heat/PEF treatments.
Effect of Squid Ink Melanin‐Fe on Iron Deficiency Anemia Remission
Authors: Lei M. , Xue C.‐H. , Wang Y.‐M. , Li Z.‐J. , Xue Y. , Wang J.‐F.
Published: September 2008

ABSTRACT:  The present study was designed to evaluate the effect of a new iron tonic (squid ink melanin‐Fe [SM‐Fe]) on remission of iron deficiency anemia (IDA) using a rat model of IDA. The rat IDA model was established with low‐iron diet feeding and caudal vein blooding. Then different dosages of SM‐Fe were given to the rats once a day by intragastric administration, with FeSO4 and FeCl3 as positive control. The content of Hemoglobin (Hb), red blood cell (RBC), hematocrit (HCT), and mean corpuscular volume (MCV) were analyzed in addition to the contents of serum iron (SI) and intracellular free erythrocyte protoporphyrin (FEP). The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) in serum was also measured. The results showed that anemia caused by iron deficiency was established as a consequence of the low‐iron diets. SM‐Fe showed an effective restoration action by returning Hb, RBC, HCT, MCV, SI, and FEP in IDA animals to normal values. An antioxidant effect was also observed that reduced MDA level, enhanced the activities of SOD and GSH–Px in serum, and protected erythrocytes from the injury of reactive oxygen species as a consequence of SM‐Fe intake. In comparison with FeSO4 and FeCl3, higher bioavailability of iron and fewer side effects were also observed. In conclusion, SM‐Fe remitted iron deficiency anemia symptoms significantly, suggesting that SM‐Fe might contribute to improving hemopoietic function in IDA rats and might be exploited as a safe, efficient new iron tonic.
Scientific Status Summary
Authors: Brody Aaron L. , Bugusu Betty , Han Jung H. , Sand Claire Koelsch , McHugh Tara H.
Published: September 2008

The Institute of Food Technologists has issued this Scientific Status Summary to inform readers of recent innovations in food packaging materials.
The Sociology of the Future: Tracing Stories of Technology and Time
Authors: Selin Cynthia
Published: September 2008

The sociology of the future is an emerging field of inquiry that works to understand future consciousness drawing from a mix of Science & Technology Studies and the practice of foresight. Through an exploration of the theories, methodologies, and quagmires of anticipation employed in the study of nanotechnology, this piece introduces the sociology of the future and suggests some ways the field is taking definition. Exploring the future tense provides a means of taking responsibility for what is to come; yet, the movement of the social sciences into the tricky terrain of the future presents tensions. Understanding plausibility, how different communities use anticipatory knowledge, and the performative role of expectations in innovation remain areas of research rich with dilemmas and delights. As social scientists begin to weave their own accounts of futures, they should pay attention to the politics of such rendering.
Analysis of the clinical efficacy of intravitreal bevacizumab in the treatment of iris neovascularization caused by proliferative diabetic retinopathy
Authors: Jiang Yanrong , Liang Xiaoying , Li Xiaoxin , Tao Yong , Wang Kai
Published: September 2008

Purpose:  To evaluate the therapeutic effect of intravitreal bevacizumab (Avastin®) (IVB) in the treatment of iris neovascularization (INV) in proliferative diabetic retinopathy (PDR).

Methods:  A retrospective analysis on data collected from 28 eyes of 22 patients with PDR was performed. The analysis included grading of INV, visual acuity (VA) and intraocular pressure (IOP) prior to and after IVB treatment.

Results:  Significant regression was noted in 20 eyes (71.4%); six eyes (21.4%) showed partial regression; no change or worsening was observed in two eyes (7.2%). VA (measured with a Snellen acuity chart) improved in five eyes (17.9%) while the remaining 23 eyes (82.1%) had no improvement. In the 11 eyes with preoperative neovascular glaucoma, IOP decreased in 10 eyes (91%) and increased in one eye (9%) after treatment.

Conclusion:  IVB treatment of INV in PDR patients shows a promising short‐term result. Further studies are needed to evaluate long‐term results.
A Handheld Computer as Part of a Portable In Vivo Knee Joint Load-Monitoring System
Authors: Szivek J. A. , Nandakumar V. S. , Geffre C. P. , Townsend C. P.
Published: September 2008

In vivo measurement of loads and pressures acting on articular cartilage in the knee joint during various activities and rehabilitative therapies following focal defect repair will provide a means of designing activities that encourage faster and more complete healing of focal defects. It was the goal of this study to develop a totally portable monitoring system that could be used during various activities and allow continuous monitoring of forces acting on the knee. In order to make the monitoring system portable, a handheld computer with custom software, a USB powered miniature wireless receiver, and a battery-powered coil were developed to replace a currently used computer, ac powered benchtop receiver, and power supply. A Dell handheld running Windows Mobile operating system programed using LABVIEW was used to collect strain measurements. Measurements collected by the handheld-based system connected to the miniature wireless receiver were compared with the measurements collected by a hardwired system and a computer based system during benchtop testing and in vivo testing. The newly developed handheld-based system had a maximum accuracy of 99% when compared to the computer based system.
A Compact and Modular Laparoscopic Grasper With Tridirectional Force Measurement Capability
Authors: Tholey Gregory , Desai Jaydev P.
Published: September 2008

The introduction of minimally invasive surgery (MIS) into the operating room has led to significant advantages over conventional open surgery. Furthermore, the migration toward robot-assisted MIS over the past decade has provided additional advantages. However, the lack of haptic feedback in these tele-operated robotic surgical systems has inhibited the surgeon’s ability to diagnose tissue as healthy or unhealthy, thereby creating a need for force feedback in these systems. This paper presents the design and development of a compact and modular laparoscopic grasper with tridirectional force measurement capability for applications in robot-assisted MIS. The instrumented laparoscopic grasper is capable of measuring the normal grasping force, as well as the manipulation forces (horizontal and vertical) during grasping tasks. The grasper also has a modular design that allows for easy conversion between different surgical modalities, such as grasping, cutting, and dissecting. Preliminary tele-operative experiments with force feedback capability through a haptic feedback device for artificial tissue characterization as well as knot tightening experiments indicate the capability of this grasper.
An Inexpensive, Highly Portable Optical to Haptic Graphical Display
Authors: Burch David , Owen Justin , Pawluk Dianne
Published: September 2008

Current methods available to represent graphical information to individuals who are blind or visually impaired are too expensive and/or cumbersome to be of practical use. Therefore, there is a need for an affordable display device capable of rendering graphical information through stimulation of working sensory systems. To further facilitate individuals, the device must be portable, as to enable them to use it in many different settings, and highly affordable, as most individuals who are blind are also unemployed. In this paper a dynamic display haptic device is described that is both affordable (<$25US) and portable (<1kg). The device uses a photo-interrupter to detect contrasts in light reflectivity for an image and vibrating solenoid motors to provide tactile feedback. The device is worn like a glove, so the tactile feedback combines with the body's kinesthetic sense of position of the hand to convey a haptic image. Preliminary tests show that a single-finger model of the device has on average a 50% object identification accuracy, which is higher than the accuracy for raised-line drawings. The device can be expanded for use of multiple fingers, while still remaining affordable (<$50US).
A Geometric Interpretation of Finite Screw Systems Using the Bisecting Linear Line Complex
Authors: Huang Chintien , Ravani Bahram , Kuo Wuchang
Published: September 2008

This paper uses the concept of bisecting linear line complex of the two position theory in kinematics to present a geometric foundation for finite displacement screw systems, with an emphasis on incompletely specified displacement of points. It is shown that the bisecting linear line complex arising from the finite displacement of points is subject to a reciprocal condition if a specific definition of pitch of finite screws is used. The screw systems of finite displacements are then characterized in terms of intersections of bisecting linear line complexes. The line varieties corresponding to the two-system and four-system associated with finite displacements of two points and a point, respectively, are illustrated. This paper demonstrates that the bisecting linear line complex provides a geometric framework for studying finite and infinitesimal kinematics.
Selection-Integrated Optimization (SIO) Methodology for Optimal Design of Adaptive Systems
Authors: Khire Ritesh A. , Messac Achille
Published: September 2008

Many engineering systems are required to operate under changing operating conditions. A special class of systems called adaptive systems has been proposed in the literature to achieve high performance under changing environments. Adaptive systems acquire this powerful feature by allowing their design configurations to change with operating conditions. In the optimization of the adaptive systems, designers are often required to select (i) adaptive and (ii) nonadaptive (or fixed) design variables of the design configuration. Generally, the selection of these variables and the optimization of adaptive systems are performed sequentially, thus being a source of suboptimality. In this paper, we propose the Selection-Integrated Optimization (SIO) methodology, which integrates the two key processes: (1) the selection of the adaptive and fixed design variables and (2) the optimization of the adaptive system, thereby eliminating a significant source of suboptimality from adaptive system optimization problems. A major challenge to integrating these two key processes is the selection of appropriate fixed and adaptive design variables, which is discrete in nature. We propose the Variable-Segregating Mapping-Function (VSMF), which overcomes this challenge by progressively approximating the discreteness in the design variable selection process. This simple yet effective approach allows the SIO methodology to integrate the selection and optimization processes and helps avoid one significant source of suboptimality from the optimization procedure. The SIO methodology finds its applications in a variety of other engineering fields, such as product family optimization. However, in this paper, we limit the scope of our discussion to adaptive system optimization. The effectiveness of the SIO methodology is demonstrated by designing a new air-conditioning system called Active Building Envelope (ABE) system.
A New Compliant Mechanical Amplifier Based on a Symmetric Five-Bar Topology
Authors: Ouyang P. R. , Zhang W. J. , Gupta M. M.
Published: September 2008

A mechanical amplifier is an important device, which together with a piezoelectric actuator can achieve motion with high resolution and long range. In this paper, a new topology based on a symmetric five-bar structure for displacement amplification is proposed, and a compliant mechanism is implemented for the amplifier. In short, the new mechanical amplifier is called a compliant mechanical amplifier (CMA). The proposed CMA can achieve large amplification ratio and high natural frequency, as opposed to the existing CMAs, in terms of topology. Detailed analysis with finite element method has further shown that a double symmetric beam five-bar structure using corner-filleted hinges can provide good performances compared with its counterpart, which is based on four-bar topology. Finally, experiments are conducted to give some validation of the theoretical analysis.
Cable-Driven Parallel Mechanisms: Application to a Locomotion Interface
Authors: Perreault Simon , Gosselin Clément M.
Published: September 2008

Over the past decade, cable-driven parallel mechanisms have been used for several purposes. In this paper, a novel application is proposed, namely, using two 6DOF cable-driven parallel mechanisms sharing a common workspace to obtain the mechanical base for the design of a locomotion interface. The methodology used to develop the architecture of the mechanisms is presented, and the two main criteria used to optimize the geometry are described. These criteria are based on the wrench-closure workspace and a detection of the mechanical interferences between all the entities of the locomotion interface (cables and moving bodies). Then, the final design is described and its performances are given. Finally, in order to validate the relevance of the mechanism for the locomotion interface’s design, tensile forces in the cables are computed to observe the maximal values reached during a typical human gait trajectory.
Design of a Microrobotic Wrist for Needle Laparoscopic Surgery
Authors: Zoppi Matteo , Sieklicki Wiktor , Molfino Rezia
Published: September 2008

This paper addresses the design of a microwrist for needle laparoscopic surgery (needlescopy) using microelectromechanical system technology and an original three degree of freedom, 3D architecture. Advancement in needlescopy drives the development of multi-DOF microtools 1–2mm in diameter with 3D mobility but standard available fabrication techniques are for 2.5D structures. Thus paper discusses the development steps and design solutions for the realization of the 3D wrist with available technology. A compliant mechanism is used, which is derived from a reference parallel kinematics mechanism architecture with three legs. A singular configuration of increased instantaneous mobility is exploited to achieve the desired 3D mobility. Alternative leg architectures are investigated to obtain satisfactory performance. The legs are fabricated as monolithic compliant structures and assembled to wrist base and end-effector. The definition of the leg geometry revealed a complex task. The steps to obtain the final design satisfying task requirements are detailed.
An Infant Surgical Table for Laser Photocoagulation: Design and Development
Authors: Ryland Kimberly , Nelson Carl A. , Hejkal Thomas
Published: September 2008

Retinopathy of prematurity, caused by abnormal blood vessel development in the retina of premature infants, is a leading cause of childhood blindness. It is treated using laser photocoagulation. Current methods require the surgeon to assume awkward standing positions, which can result in injury to the surgeon if repeated often. To assist surgeons in providing quality care and prevent occupational injury, a new infant surgical table was designed. The engineered solution is an attachment to a standard surgical table, saving cost and space. The adjustable height and tilt provided by the standard table combined with the 360 deg rotation designed into the attachment allow the surgeon to sit during surgery. The infant table incorporates several novel features. Critical cords and tubes are routed through an aperture at the center of the attachment to avoid pulling and kinking. A four-bar locking mechanism allows easy attachment to standard medical railing. A straight-line mechanism provides positive locking of the rotation, allowing precise positioning of the infant. Load-deflection testing was carried out using an infrared camera tracking system, and expert feedback was also obtained in a clinical setting to ascertain proper function. Strength testing showed acceptably small deflections and stresses under representative loading conditions. Benchtop and clinical testing of the infant table have demonstrated that it reliably and safely meets the design objectives. The device also shows promise for use in other infant or pediatric treatment and in small-animal veterinary practice.
A Noninvasive System for Biomechanical Properties Measurement of Soft Tissue
Authors: Mayrose James
Published: September 2008

A device for measuring the biomechanical properties of soft tissue via palpation was developed. The device, which is worn by a medical professional, incorporates sensors that collect data on the position of the users’ hand in three-dimensional space as well as the force that the user applies to the tissue. The depth of palpation, the force used to achieve that depth, and the thickness of the tissue obtained from a computed tomography scan of the abdomen were used to calculate the stiffness properties of each individual layer of tissue. Some experimental data obtained by curve fitting force-displacement curves are presented. The data obtained from this experiment illustrates the potential of this device to be used for accurate measurement of soft tissue properties.
An electron impact emission spectroscopy flux sensor for monitoring deposition rate at high background gas pressure with improved accuracy
Authors: Lu C. , Blissett C. D. , Diehl G.
Published: September 2008

Electron impact emission spectroscopy (EIES) has been proven to be a critical tool for film composition control during codeposition processes for the fabrication of multicomponent thin film materials including the high-efficiency copper-indium-gallium-diselenide photovoltaic cells. This technique is highly specific to atomic species because the emission spectrum of each element is unique, and the typical width of atomic emission lines is very narrow. Noninterfering emission lines can generally be allocated to different atomic species. However, the electron impact emission spectra of many molecular species are often broadband in nature. When the optical emission from an EIES sensor is measured by using a wavelength selection device with a modest resolution, such as an optical filter or monochromator, the emissions from common residual gases may interfere with that from the vapor flux and cause erroneous flux measurement. The interference is most pronounced when measuring low flux density with the presence of gases such as in reactive deposition processes. This problem is solved by using a novel EIES sensor that has two electron impact excitation sources in separate compartments but with one common port for optical output. The vapor flux is allowed to pass through one compartment only. Using a tristate excitation scheme and appropriate signal processing technique, the interfering signals from residual gases can be completely eliminated from the output signal of the EIES monitor for process control. Data obtained from Cu and Ga evaporations with the presence of common residual gases such as CO2 and H2O are shown to demonstrate the improvement in sensor performance. The new EIES sensor is capable of eliminating the effect of interfering residual gases with pressure as high as in the upper 10−5Torr range.
Platinum-coated probes sliding at up to 100 mm/s against lead zirconate titanate films for atomic force microscopy probe-based ferroelectric recording technology
Authors: Kwak Kwang Joo , Bhushan Bharat
Published: September 2008

With the advent of scanning probe microscopes, probe-based data recording technologies are being developed for ultrahigh areal density. In alternative ferroelectric data storage, a conductive atomic force microscope (AFM) tip is placed in contact on a lead zirconate titanate (PZT) layer as the ferroelectric film. Ferroelectric domains can be polarized by applying short voltage pulses between the AFM tip and the bottom electrode that exceed the coercive field of the PZT layer, resulting in local, nonvolatile changes in the electronic properties of the underlying film. By monitoring the piezoelectric vibration of the ferroelectric film caused by an external ac voltage, the domain structure can be visualized. A degradation due to a voltage pulse to the PZT film occurs and is one reliability concern, called ferroelectric fatigue. Another important reliability concern is tip wear during tip-sample contact. The understanding and the improvement of tip wear, particularly at high velocities needed for high data rate recording, is critical to the commercialization of ferroelectric memories. In this study, wear experiments are performed using a Pt-coated tip sliding against a PZT layer at sliding velocities ranging from 0.1 to 100 mm/s. A silicon grating sample and software to deconvolute tip shape are used to characterize the change in the tip shape and evaluate the tip radius and its wear volume. The tip wear mechanism is dependent on the operating conditions. At velocities up to 1 mm/s, it is adhesive wear assisted with thermally activated stick slip and, at higher velocities, it is adhesive and impact wear. In wear life threshold experiments, the threshold reaches a smaller sliding distance at higher loads. In high-temperature experiments at 80 °C, the wear rate is high compared to that at 20 °C.
Study of characteristic fragmentation of nanocarbon by the scanning atom probe
Authors: Nishikawa Osamu , Taniguchi Masahiro , Saito Yahachi
Published: September 2008

Six nine purity graphite and single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), multiple-walled carbon nanotube (MWCNT) are mass analyzed by the scanning atom probe. Surface atoms well exposed to the external field are field evaporated and individual evaporated fragment ions are detected. Each specimen exhibits a characteristic mass spectrum of fragmented cluster ions. The SWCNT exhibits the cleanest mass spectrum with a small amount of hydrogen. The commercially available DWCNT shows two types of mass spectra: one is fairly clean and the other with many C15(H2O)m clusters. The laboratory grown MWCNT shows various doubly and triply ionized cluster ions indicating strong bonding between the atoms forming the clusters. The sharper the mass peak is and the higher the multiplicity of charge is, the stronger the binding between atoms forming the clusters. The commercially available pure graphite shows three types of mass spectra, fairly clean spectra without large C–H clusters, spectra with various C–H clusters with a large mass peak of C28H4, and spectra with larger clusters such as C38Hn. The magic number forming the clusters is discussed.
Technique to measure contact angle of micro/nanodroplets using atomic force microscopy
Authors: Jung Yong Chae , Bhushan Bharat
Published: September 2008

Contact angle is the primary parameter that characterizes wetting; however, the measurement techniques have been limited to droplets with a diameter as low as about 50 μm. The authors developed an atomic force microscopy-based technique to measure the contact angle of micro- and nanodroplets deposited using a modified nanoscale dispensing tip. The obtained contact angle results were compared with those of a macrodroplet (2.1 mm diameter). It was found that the contact angle on various surfaces decreases with decreasing the droplet size.
Effect of swift heavy ion irradiation on the hardness of chromium nanorods
Authors: Nagar Rupali , Mehta B. R. , Singh J. P. , Jain D. , Ganesan V. , Kesapragada S. V. , Gall D.
Published: September 2008

The present study reports the use of swift heavy ion irradiation as a means to tailor the hardness of chromium nanorod coatings. Arrays of slanted and straight Cr nanorods, 1–2μm long and 300–500nm in diameter, were grown by dc magnetron sputter glancing angle deposition on Si(100) substrates patterned with 500nm diameter polystyrene spheres. The samples were irradiated with 100MeV Ag+8 ions at three different fluence values of 1013, 5×1013, and 1014ions∕cm2, while maintaining the samples at 80K temperature. The as-deposited samples exhibit a fibrous structure that smoothens after irradiation. Nanoindentation tests performed on these samples reveal that the hardness of the nanorods increases with fluence. For slanted nanorods, the samples irradiated at maximum fluence show an almost 300% increase in hardness as compared to their pristine counterparts. The corresponding increase in the case of straight nanorods was observed to be 77%. This fluence-dependent hardness in Cr nanorods is explained in terms of an ion-irradiation induced defect formation and a decrease in the grain size, as confirmed by glancing angle x-ray diffraction.
Surface science investigations of photoprocesses in model interstellar ices
Authors: Thrower J. D. , Collings M. P. , McCoustra M. R. S. , Burke D. J. , Brown W. A. , Dawes A. , Holtom P. D. , Kendall P. , Mason N. J. , Jamme F. , Fraser H. J. , Clark I. P. , Parker A. W.
Published: September 2008

The kinetic energy of benzene and water molecules photodesorbed from astrophysically relevant ices on a sapphire substrate under irradiation by a UV laser tuned to the S1←S0 π→π* transition of benzene has been measured using time-of-flight mass spectrometry. Three distinct photodesorption mechanisms have been identified—a direct adsorbate-mediated desorption of benzene, an indirect adsorbate-mediated desorption of water, and a substrate-mediated desorption of both benzene and water. The translational temperature of each desorbing population was well in excess of the ambient temperature of the ice matrix.
High rate deposition of photocatalytic TiO2 films with high activity by hollow cathode gas-flow sputtering method
Authors: Kubo Yoshiyuki , Iwabuchi Yoshinori , Yoshikawa Masato , Sato Yasushi , Shigesato Yuzo
Published: September 2008

Photocatalytic TiO2 films were deposited by a hollow cathode gas-flow sputtering method using two Ti metal targets mounted parallel to each other. The Ar and O2 flow rates were 3000 and 0–50SCCM (SCCM denotes cubic centimeter per minute at STP), respectively, and total gas pressure during the deposition was maintained at 45Pa. The highest deposition rate for the photocatalytic TiO2 films was 162nm∕min at 30SCCM of O2 flow. The as-deposited films and postannealed films, annealed in air at 300°C for 1h, were used to carry out photocatalytic decomposition of acetaldehyde (CH3CHO). In particular, the postannealed films showed extremely high photocatalytic activity compared to the photocatalytic activity of films deposited by conventional reactive sputtering.
Programmable memory devices using gold nanoparticles capped with alkanethiols of different carbon chain lengths
Authors: Lai Pei Ying , Chen J. S.
Published: September 2008

Electrical bistability is demonstrated in a polymer memory device using polystyrene containing an organic conjugated compound (8-hydroxyquinoline) and gold nanoparticles (Au NPs) capped with different alkanethiols of carbon chain lengths as the active layer between two metal electrodes. Au NPs capped with three different alkanethiols [1-octanethiol (C8), 1-dodecanethiol (C12), and 1-octadecanethiol (C18)] are investigated for the correlation with the memory performance. Above a threshold voltage, the as-fabricated device can transit from low conductivity state to high conductivity state. By applying a certain positive voltage, the high conductivity state can return to the low conductivity state. The switch-on voltages of thiol-derivatized Au NPs based organic memory devices are almost the same. Current fluctuations appeared in the static current–voltage characteristic of Au NPs capped with a 1-octadecanethiol (C18) based memory device. This feature is related to quantized charging and discharging of Au NPs because of the Coulomb repulsion between electrons confined in nanocrystals.
Recent advances to enhance low Earth orbit space simulation
Authors: Collins Frank G.
Published: September 2008

Accurate ground-based simulation of low Earth orbit (LEO) conditions experienced by a satellite has proven to be a challenge. Recent progress that has been made toward the development of means for simulating portions of the LEO environment will be reviewed. A satellite in LEO has a speed relative to the atmosphere of approximately 8km∕s. The neutral atmospheric molecules exchange momentum upon collision with the surfaces of the satellite, leading to drag, lift, and moments, but ground facilities still have trouble simulating pure beams of ground state atmospheric gases at this speed. The most important atmospheric species, atomic oxygen, collides with ram-direction satellite surfaces with a relative energy of 5eV. The solar UV spectrum in LEO is a composite of many emission lines and continuum, which must be simulated using special lamp systems. Thruster plumes and outgassing molecules result in a contamination atmosphere close to the spacecraft surface. Energetic atomic oxygen atoms in the presence of solar UV radiation and contamination gases can produce synergistic effects that result in many chemical reactions on or in the vicinity of the outer satellite surfaces. These reactions can lead to structural or operational damage to various satellite components, such as a reduction in the effectiveness of thermal control paints, cleanliness of optical lenses, and the reduction of the output of solar cells. Several techniques for generating beams of 5eV atomic oxygen in the ground state will be reviewed as well as special diagnostic instrumentation developed to detect atomic oxygen. These are combined in space simulation chambers for a more complete study of materials degradation. Some electric thrusters exit directly to the vacuum of space. Their exhaust and plume simulation presents unique vacuum chamber pumping problems. Specially designed cryogenic pumps to simulate the conditions that these electric thrusters will experience in orbit will be described. Reference to inventories of space simulation chambers will be given.
Microstructural evolution of nickel-germanide in the Ni1−xTax/Ge systems during in situ annealing
Authors: Lee Jae-Wook , Bae Jee-Hwan , Park Min-Ho , Kang Han-Byul , Kim Hyoungsub , Yang Cheol-Woong
Published: September 2008

The formation and morphological evolution of the germanides formed in the Ni1−xTax/Ge (x=0 and 0.1) systems were examined using ex situ and in situ annealing experiments. It was observed that the Ni-germanide in the Ni0.9Ta0.1/Ge system remained stable at temperatures up to 550 °C whereas the Ni-germanide in the Ni/Ge system agglomerated and was unstable. Microstructural and chemical analyses of the Ni0.9Ta0.1/Ge system during and after in situ annealing in a transmission electron microscope confirmed that the Ta-rich layer was formed by the accumulation of Ta atoms on the interface between the Ni0.9Ta0.1 alloy film and the Ge substrate during the diffusion reaction, and a small amount of residual Ta was found in the Ni-germanide grains. Ultimately, the Ta-rich layer helps reduce the level of agglomeration in the Ni-germanide film and improves the thermal stability of Ni-germanide.
Advances in magnetometry through miniaturization
Authors: Edelstein A. S. , Burnette J. , Fischer G. A. , Cheng S. F. , Egelhoff W. F. , Pong P. W. T. , McMichael R. D. , Nowak E. R.
Published: September 2008

Recent innovations may lead to magnetic sensors that are smaller, more sensitive, and/or cost less than current magnetometers. Examples of this are the chip scale atomic magnetometer, magnetic tunnel junctions with MgO barriers, and a device for minimizing the effect of 1∕f noise, the microelectromechanical system (MEMS) flux concentrator. In the chip scale atomic magnetometer, researchers have been able to fabricate the light source, optics, heater, optical cell, and photodiode detector in a stack that passes through a silicon wafer. Theoretical and subsequent experimental work has led to the observation of magnetoresistance values of 400% at room temperature in magnetic tunnel junctions with MgO barriers. This large magnetoresistance occurs because electrons in the majority band can tunnel more easily through the MgO barrier than electrons in the minority band. The MEMS flux concentrator has the potential to increase the sensitivity of magnetic sensors at low frequencies by more than an order of magnitude. The MEMS flux concentrator does this by shifting the operating frequency to higher frequencies where the 1∕f noise is much smaller. The shift occurs because the motion of flux concentrators on MEMS flaps modulates the field at kilohertz frequencies at the position of the sensor. Though miniaturization is generally beneficial, trade-offs are necessary because some properties, such as noise, worsen with decreasing size.
Fabrication of stationary micro-optical shutter based on semiconductor-to-metallic phase transition of W-doped VO2 active layer driven by an external voltage
Authors: Soltani M. , Chaker M. , Haddad E. , Kruzelecky R. , Margot J. , Laou P. , Paradis S.
Published: September 2008

The authors have successfully fabricated stationary micro-optical shutter arrays based on the well-known transmitting semiconductor (on) to the reflecting metallic (off) phase transition of thermochromic W-doped VO2 active layers operating at room temperature and driven by an external voltage. This shutter consists of 16 active planar micro-optical slits for which the optical switching (either transmittance or reflectance) can be controlled individually. This allows performing any desirable on-off switching combinations. The current-voltage characteristic of the micro-slit shows that the current jumps when the phase transition occurs. Transmittance switching as high as 25 dB and reflectance switching of about 6 dB were achieved with this device at λ=1.55 μm. Therefore, this electrically controllable VO2-array can be used as a stationary Hadamard shutter to increase the sensitivity of infrared spectrometers.
Three dimensional image construction and spectrum extraction from two dimensional elemental mapping in Auger electron spectroscopy
Authors: Urushihara N. , Iida S. , Sanada N. , Suzuki M. , Paul D. F. , Bryan S. , Nakajima Y. , Hanajiri T. , Kakushima K. , Ahmet P. , Tsutsui K. , Iwai H.
Published: September 2008

Three dimensional Auger elemental distributions have been constructed from the combination of high spatial resolution, two dimensional Auger maps obtained at multiple sputter depths. These three dimensional elemental distributions have been used to compare the interfacial regions for two kinds of silicon on insulator wafers. It is clearly seen that silicon oxide is formed as an island structure for the SIMOX specimen, whereas the UNIBOND specimen has a featureless structure at the Si∕SiO2 interface. Linear least squares fitting from several two dimensional maps obtained at different energies have been used to produce energy dispersive spectra from specific regions of high spatial resolution Auger maps. This technique was used to examine the interface region exposed from sputter craters through a silicon dioxide layer on a silicon substrate and through a Ni silicide film on a silicon substrate. The Si LVV spectra for the elemental silicon, oxide, and silicide components extracted from the multiple energy two dimensional maps can be used to map the chemical components in the interfacial regions.