bluuebunny/crossref_metadata_2025 huggingface dataset:
Climatic Fluctuations and Forecasting of Streamflow in the Lower Colorado River Basin1
Authors: Thomas Blakemore E.
Published: October 2007

Abstract:  Water‐resource managers need to forecast streamflow in the Lower Colorado River Basin to plan for water‐resource projects and to operate reservoirs for water supply. Statistical forecasts of streamflow based on historical records of streamflow can be useful, but statistical assumptions, such as stationarity of flows, need to be evaluated. This study evaluated the relation between climatic fluctuations and stationarity and developed regression equations to forecast streamflow by using climatic fluctuations as explanatory variables. Climatic fluctuations were represented by the Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), and Southern Oscillation Index (SOI). Historical streamflow within the 25‐ to 30‐year positive or negative phases of AMO or PDO was generally stationary. Monotonic trends in annual mean flows were tested at the 21 sites evaluated in this study; 76% of the sites had no significant trends within phases of AMO and 86% of the sites had no significant trends within phases of PDO. As climatic phases shifted in signs, however, many sites had nonstationary flows; 67% of the sites had significant changes in annual mean flow as AMO shifted in signs. The regression equations developed in this study to forecast streamflow incorporate these shifts in climate and streamflow, thus that source of nonstationarity is accounted for. The R2 value of regression equations that forecast individual years of annual flow for the central part of the study area ranged from 0.28 to 0.49 and averaged 0.39. AMO was the most significant variable, and a combination of indices from both the Atlantic and Pacific Oceans explained much more variation in flows than only the Pacific Ocean indices. The average R2 value for equations with PDO and SOI was 0.15.
Evaluation of Rio Grande Management Alternatives Using a Surface‐Water/Ground‐Water Model1
Authors: Wilcox Laura Jean , Bowman Robert S. , Shafike Nabil G.
Published: October 2007

Abstract:  Previous investigations observed significant seepage losses from the Rio Grande to the shallow aquifer between Socorro and San Antonio, New Mexico. High‐resolution telescopic modeling was used along a 10‐km reach of the Rio Grande and associated drains and canals to evaluate several management alternatives aimed at improving river conveyance efficiency. Observed data consisted of ground‐water and surface‐water elevations, seepage rates along the Rio Grande and associated canals and drains, and borehole geology. Model calibration was achieved by adjusting hydraulic conductivity and specific storage until the output matched observed data. Sensitivity analyses indicated that the system was responsive to changes in hydrogeologic properties, especially when such alterations increased vertical connectivity between layers. The calibrated model predicted that removal of the low flow conveyance channel, a major channel draining the valley, would not only decrease river seepage by 67%, but also decrease total flow through the reach by 75%. The decreased flow through the reach would result in increased water logging and an average increase in ground‐water elevations of 1.21 meter. Simulations of the system with reduced riparian evapotranspiration rates or a relocated river channel also predicted decreased river seepage, but to a much lesser degree.
Mitf contributes to melanosome distribution and melanophore dendricity
Authors: Kawasaki Akiha , Kumasaka Mayuko , Satoh Akira , Suzuki Makoto , Tamura Koji , Goto Toshiyasu , Asashima Makoto , Yamamoto Hiroaki
Published: October 2007

Mitf is a transcription factor of the basic/helix‐loop‐helix/leucine‐zipper family which is indispensable for development of melanocytes and the retinal pigment epithelium. Our previous work using Xenopus laevis as a model system suggested that Mitf regulates melanosome dispersal in vivo though whether this was via melanosome transport or melanophore dendricity was not obvious. To better understand the role of Mitf, we have now characterized neural tube cultures from wild‐type Mitf‐injected or a dominant‐negative Mitf‐injected embryos and compared them with controls. In vitro, lower levels of Mitf activity induced less dendritic melanophores with aggregated melanosomes, whereas melanophores overexpressing Mitf had an extensive dendritic morphology with dispersed melanosomes. Moreover, immunorfluoresence assays reveal that expression of a dominant‐negative Mitf leads to decreased Rab27a expression. These results suggest that Mitf is involved in the regulation of melanosome transport and the level of dendricity in melanophores.
Effects of hydroxyethyl starches on hemostasis
Authors: KOZEK‐LANGENECKER SIBYLLE A. , SCHARBERT GISELA
Published: October 2007

Hydroxyethyl starch (HES) solutions are frequently used colloidal plasma expanders which are indicated to restore and maintain intravascular volume and to improve tissue perfusion. The development of HES solutions since their introduction into clinical practice has centered on designing starch molecules with an increased oncotic pressure and hemodynamic efficacy while minimizing the risk of adverse reactions such as anticoagulant effects. This article reviews specific anticoagulant side effects of various HES generations, including hetastarch, pentastarch and tetrastarch. Slowly degradable HES solutions have a more pronounced impact on coagulation than rapidly degradable HES. The decrease in factor VIII and von Willebrand factor may be due to complex binding to HES macromolecules and accelerated elimination. Extracellular coating of platelets by HES molecules results in an inhibition of platelet aggregation and adhesion. Thrombin–fibrin interaction, fibrin polymerization, activation of factor XIII, as well as clot resistance to fibrinolytic degradation is reduced in the presence of HES. Balanced salt solutions cause fewer coagulation abnormalities than HES dissolved in saline. Possible approaches to reverse HES‐induced coagulopathy may include the administration of desmopressin, fibrinogen and factor XIII concentrates. Hetastarch attenuates hypercoagulability in patients at risk for thrombotic episodes and increases perioperative bleeding, while blood loss and transfusion requirements were not different in patients exposed to tetrastarch compared with gelatin or albumin. Accordingly, tetrastarch appears to be a suitable volume expander in the routine perioperative setting because of adequate volume efficacy and minimal risk for hemostatic derangements. Contraindications and maximum daily doses need to be acknowledged.
Non‐Structural Protein 3A for Differentiation of Foot‐and‐Mouth Disease Infected and Vaccinated Animals in Haryana (India)
Authors: Kumar N. , Sharma R. , Kakker N. K.
Published: October 2007

There are severe international trade restrictions on foot‐and‐mouth disease (FMD) affected areas. Because of endemic nature of FMD, India started FMD control programme (FMD‐CP) using mass vaccination in selected states including Haryana (year 2003). Although no significant incidence of the disease was reported after launching FMD‐CP in the state but in order to participate in international trade of animal and animal products, veterinary authorities have to prove that there is no FMD virus (FMDV) circulation in the animal population, for which it is necessary to differentiate the FMD infected and vaccinated animals. For this purpose, an in‐house indirect ELISA utilizing baculovirus‐expressed FMDV non‐structural protein (NSP) 3A was used to find evidence for virus circulation (prevalence of anti‐NSP 3A‐specific antibodies) by examining serum samples that were collected either before start of FMD‐CP or after completion of third phase (Pre‐4th) of vaccination in Haryana (India). A significant reduction (P < 0.01) in prevalence of anti‐NSP 3A‐specific antibodies (possibly carriers) was observed 2 years after launching FMD‐CP in Haryana. However, in cattle the percentage of animals with anti‐NSP 3A‐specific antibodies was found to be significantly higher (P < 0.01) than buffalo, both before (P < 0.01) and after (P < 0.01) launching FMD‐CP in the state. The findings of this study suggest that use of FMDV vaccine in cattle and buffaloes in endemic areas reduces virus circulation (carriers) in the vaccinated herds and that the current 3ANSP‐ELISA can be successfully used to monitor the FMDV circulation in endemic areas.
Human leukocyte antigen DR status and clinical features in Japanese patients with type 1 autoimmune hepatitis
Authors: Miyake Yasuhiro , Iwasaki Yoshiaki , Takaki Akinobu , Onishi Toru , Okamoto Ryoichi , Takaguchi Kouichi , Ikeda Hiroshi , Makino Yasuhiro , Kobashi Haruhiko , Sakaguchi Kohsaku , Shiratori Yasushi
Published: October 2007

Aim:  Human leukocyte antigen (HLA) DR status affects the clinical features of autoimmune hepatitis. In Caucasians, patients with DR3 have poorer outcomes. In Japan, the relationship between HLA DR status and clinical features has yet to be fully examined.

Methods:  We investigated 79 patients with type 1 autoimmune hepatitis who underwent liver biopsy and were screened for HLA DR status by the polymerase chain reaction sequence specific oligonucleotide hybridization method.

Results:  Fifty‐five patients had DR4 and 23 had DR2. Thirteen patients had both DR2 and DR4. None had DR3. Of patients aged <30 years, 70% did not have DR4. A tendency toward higher serum levels of immunoglobulin G was seen in patients with DR4 compared to those without, while patients with neither DR2 nor DR4 had lower serum levels of immunoglobulin G than those with only DR2 and those with only DR4. Patients with DR2 had a lower frequency of concurrentautoimmune disease. Concurrence of thyroid disease was seen only in patients with DR4. The cumulative incidental rate of the normalization of serum alanine aminotransferase levels within six months after the introduction of corticosteroid treatment was not associated with HLA DR status.

Conclusion:  HLA DR status is considered to affect the clinical features of Japanese patients with type 1 autoimmune hepatitis. Japanese patients with DR2 may have different clinical features from others. In addition, diagnoses of type 1 autoimmune hepatitis should be made carefully in Japanese patients with neither DR2 nor DR4 and in those aged <30 years.
Acoustic Measurement of Potato Cannon Velocity
Authors: Courtney Michael , Courtney Amy
Published: October 2007

Potato cannon velocity can be measured with a digitized microphone signal. A microphone is attached to the potato cannon muzzle, and a potato is fired at an aluminum target about 10 m away. Flight time can be determined from the acoustic waveform by subtracting the time in the barrel and time for sound to return from the target. The potato velocity is simply flight distance divided by flight time.
Relating the Stored Magnetic Energy of a Parallel-Plate Inductor to the Work of External Forces
Authors: Gauthier N.
Published: October 2007

Idealized models are often used in introductory physics courses. For one, such models involve simple mathematics, which is a definite plus since complex mathematical manipulations quickly become an obstacle rather than a tool for a beginner. Idealized models facilitate a student's understanding and grasp of a given physical phenomenon, yet they convey the essential elements of a sometimes intricate and abstract physical concept. It is thus worthwhile to use available models, or to develop new ones, for use in the introductory classroom. Early discussions of electric energy storage within the framework of the infinite parallel-plate capacitor model1 are an excellent case in point. In this case one can show, through relatively simple mathematical manipulations, that the work done by an external agent in order to increase the separation between the plates is equal to the corresponding change in the electrical energy of the system. The purpose of this paper is to show that a similar model can also be used to discuss magnetic energy storage based on a calculation of the work done by the external forces that act on the system, a subject that is greatly neglected at the introductory level. We examine this system next.
Precipitation in the Solar System
Authors: McIntosh Gordon
Published: October 2007

As an astronomy instructor, I am always looking for commonly observed Earthly experiences to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote a short TPT article on frost.1 This paper is on the related phenomena of precipitation. Precipitation, so common on most of the Earth's surface as rain, snow, and other forms of water, also occurs on other bodies in the solar system. However, the precipitating chemical on the other bodies is rarely water, may never reach the solid surface of the body, and may even occur on bodies that do not have a well-defined solid surface.
Methyl Steroids. Studies on the Synthesis of 4-Methyl- and 4,4-Dimethyl-25-hydroxycholestan-3-one Derivatives
Authors: Skiera Iwona , Paryzek Zdzisław
Published: October 2007

The synthetic routes to 25-hydroxy derivatives of 4-methylcholest-4-ene and 4,4-dimethylcholest-5-ene from methyl lithocholate and methyl 3β-acetoxy-24-homochol-5-en-25-oate (6) have been investigated. The cholest-5-ene-3β,25-diol (7), readily available from 6, was transformed in a few steps into the title compounds. It was also found that bromination of 24-acetoxy-5β-cholan-3-one (1) and of its enol acetate followed by dehydrobromination is not a regioselective reaction. Formation of mixtures of 2β-bromo-3-oxo and 4β-bromo-3-oxo compounds, which gave mixtures of 24-acetoxychol-4-en-3-one (4) and 24-acetoxy-5β-chol-1-en-3-one (5) of similar polarity was observed. 4-Methyl-25-hydroxycholest-4-en-3-one (14) and 4-methyl-25-hydroxycholesta-1,4-dien-3-one (16) are potential substrates for the preparation of 4-methyl analogs of vitamin D3.
Synthesis of Novel Carbocyclic Nucleosides and Pro-Tides Derived from 4-Oxatricyclo[4.2.1.03,7]nonane-9-methanol
Authors: Hřebabecký Hubert , Dračínský Martin , Holý Antonín
Published: October 2007

(1R*,2R*,3R*,6R*,7S*)-2-Amino-4-oxatricyclo[4.2.1.03,7]nonane-9-methanol (9) was prepared from (1R*,2R*,3R*,4S*)-bicyclo[2.2.1]hept-5-ene-2,3-dimethanol by treatment with benzyl azidoformate followed by hydrogenolysis. The amine9was transformed to thymine and purine nucleoside analogues. The prepared analogues were converted to corresponding Pro-Tides by treatment with methylN-[chloro(phenoxy)phosphoryl]-L-alaninate in the presence of 1-methylimidazole ortert-butylmagnesium chloride.
Ethical and policy issues relating to progenitor-cell-based strategies for prevention of atherosclerosis
Authors: Liao S M , Goldschmidt P J , Sugarman J
Published: October 2007

Objective:

To examine important ethical and societal issues relating to the use of progenitor-cell-based strategies for disease prevention, particularly atherosclerosis.

Background:

Several nascent lines of evidence suggest the feasibility of using progenitor cells to reverse the health consequence of atherosclerosis. Such potential uses of progenitor cells are scientifically exciting, yet they raise important ethical and societal issues.

Method:

The Working Group on Ethics of Progenitor Cell-based Strategies for Disease Prevention met to discuss the relevant issues. Several drafts of a report were then circulated to the entire Working Group for comments until a consensus was reached.

Results:

Scientific evidence suggests the appropriateness of using progenitor-cell-based strategies for some rare conditions involving atherosclerosis, but additional preclinical data are needed for other, more prevalent conditions before human trials begin. All such trials raise a set of ethical issues, especially since trials aimed at prevention rather than treatment may involve persons who do not yet have disease but will be exposed to the risks of interventions. In addition, enrolment in prevention trials may be hazardous and harmful if participants erroneously believe experimental interventions will necessarily prevent disease. Finally, given the high prevalence of atherosclerosis, there are some important public policy implications of taking such an approach to prevention, including the sources of progenitor cells for such interventions as well as the allocation of health resources.

Conclusion:

Potential uses of progenitor-cell-based strategies for preventing atherosclerosis must be considered in the context of a range of social and ethical issues.
Medical ethics on film: towards a reconstruction of the teaching of healthcare professionals
Authors: Volandes Angelo
Published: October 2007

The clinical vignette remains the standard means by which medical ethics are taught to students in the healthcare professions. Although written or verbal vignettes are useful as a pedagogic tool for teaching ethics and introducing students to real cases, they are limited, since students must imagine the clinical scenario. Medical ethics are almost universally taught during the early years of training, when students are unfamiliar with the clinical reality in which ethics issues arise. Film vignettes fill in that imaginative leap. By providing vivid details with images, film vignettes offer rich and textured details of cases, including the patient’s perspective and the clinical reality. Film vignettes provide a detailed ethnography that allows for a more complete discussion of the ethical issues. Film can serve as an additional tool for teaching medical ethics to members of the healthcare professions.
Inappropriate attitudes, fitness to practise and the challenges facing medical educators
Authors: Whiting Demian
Published: October 2007

The author outlines a number of reasons why morally inappropriate attitudes may give rise to concerns about fitness to practise. He argues that inappropriate attitudes may raise such concerns because they can lead to harmful behaviours (such as a failure to give proper care or treatment), and because they are often themselves harmful (both because of the offence that they can cause and because of the unhealthy pall that they may cast over relations between healthcare practitioners and patients). He also outlines some of the challenges that the cultivation and assessment of attitudes in students raise for medical educators and some of the ways in which those challenges may be approached and possibly overcome.
Reflective professionalism: interpreting CanMEDS’ “professionalism”: Table 1
Authors: Verkerk M A , de Bree M J , Mourits M J E
Published: October 2007

Residency training in the Netherlands is to be restructured over the coming years. To this end a general competence profile for medical specialists has been introduced. This profile is nearly the same as the Canadian CanMEDS 2000 model, which describes seven general areas of medical specialist competence, one of which is professionalism. In order to establish a training programme for residents and their instructors based on this competence, it is necessary to develop a vision that does justice to everyday medical practice. The two most prevailing views of professionalism—as personal, or as a behavioural characteristic—fall short of this. Only when professionalism is understood as reflective professionalism does it encompass the fundamental contextuality of medical treatment. This means that the focus of training and assessment must be shifted to accountability for treatment.
Children, Gillick competency and consent for involvement in research: Figure 1
Authors: Hunter D , Pierscionek B K
Published: October 2007

This paper looks at the issue of consent from children and whether the test of Gillick competency, applied in medical and healthcare practice, ought to extend to participation in research. It is argued that the relatively broad usage of the test of Gillick competency in the medical context should not be considered applicable for use in research. The question of who would and could determine Gillick competency in research raises further concerns relating to the training of the researcher to make such a decision as well as to the obvious issue of the researcher’s personal interest in the project and possibility of benefiting from the outcome. These could affect the judgment of Gillick competency if the researcher is charged with making this decision. The above notwithstanding, there are two exceptional research situations in which Gillick competency might be legitimately applied: (1) when the research is likely to generate significant advantages for the participants while exposing them to relatively minor risks, and (2) when it is likely to generate great societal benefit, pose minimal risks for the participants and yet raise parental objection. In both cases, to ensure that autonomy is genuinely respected and to protect against personal interest, Gillick competency should be assessed by an individual who has no interest or involvement in the research.
Moral theories may have some role in teaching applied ethics
Authors: Benatar D
Published: October 2007

In a recent paper, Rob Lawlor argues that moral theories should not be taught in courses on applied ethics. The author contends that Dr Lawlor’s arguments overlook at least two important roles that some attention to ethical theories may play in practical ethics courses. The conclusion is not that moral theorymustbe taught, but rather that there is more to be said for it than Dr Lawlor’s arguments reveal.
REAL-TIME, ON-LINE MONITORING OF DRINKING WATER FOR WATERBORNE PATHOGEN CONTAMINATION WARNING
Authors: ADAMS JOHN A. , MCCARTY DAVID
Published: October 2007

The increasing value of safe, purified water in today's global environment presents many challenges for improving water purification processes while accelerating water quality monitoring technologies. These challenges include: escalating worldwide security threats, increasing demands by consumers and regulatory agencies for higher water quality standards, and proliferation of contamination events.

A major concern in protecting water purity is the detection and control of harmful microorganisms in water sources, treatment, and distribution. Due to the length of time for standard laboratory methods to yield results, typically 24-72 hours, current analytical techniques have not been able to reliably detect microorganisms in real time and provide an immediate warning of biological contamination.

Through years of research and development, an emerging technology called MALS (multi-angle light scattering) can now achieve on line, real time detection and classification of microorganisms in water. The method utilizes a laser beam focused into a slip-stream of water and the light scattered by microorganisms generates unique patterns. These “bio-optical signatures” are instantaneously captured by photodetectors, matched against catalogue profiles in an on-board data base, and subsequently classified within minutes of detection. The system can then immediately alert personnel to the contamination event while extracting a water sample for further confirmation.
CHIP-SIZE WAVELENGTH DETECTORS
Authors: SCHMIDT OLIVER , KIESEL PETER , BASSLER MICHAEL , JOHNSON NOBLE
Published: October 2007

Chip-size wavelength detectors are described that can resolve the spectrum of the incident light with high accuracy over a broad spectral range. The devices can be configured either as compact spectrometers or precise wavelength shift detectors. Applications that are anticipated to benefit from the spectrometers include reagentless optical identification of analytes in fluidic and aerosol samples. The wavelength shift detector is widely applicable as read-out instrument for optical sensors in which a stimulus (e.g., temperature, strain, PH-value, etc.) results in a wavelength shift of an optical output signal, examples include the interrogation system for Fiber Bragg Grating sensors, photonic crystal sensors, Fabry-Perot type sensors, and sensors in which an analyte influences a laser cavity and thereby its emission wavelength.
PROGRAMMABLE ADAPTIVE SPECTRAL IMAGERS FOR MISSION-SPECIFIC APPLICATION IN CHEMICAL/BIOLOGICAL SENSING
Authors: GOLDSTEIN NEIL , VUJKOVIC-CVIJIN PAJO , FOX MARSHA , ADLER-GOLDEN STEVEN , CLINE JASON , GREGOR BRIAN , LEE JAMINE , SAMUELS ALAN C. , HIGBEE SHAWN D. , BECKER LATIKA S. , OOI TENG
Published: October 2007

An innovative passive standoff system for the detection of chemical/biological agents is described. The spectral, temporal and spatial resolution of the data collected are all adjustable in real time, making it possible to keep the tradeoff between the sensor operating parameters at optimum at all times. The instrument contains no macro-scale moving parts and is therefore an excellent candidate for the development of a robust, compact, lightweight and low-power-consumption sensor. The design can also serve as a basis for a wide variety of spectral instruments operating in the visible, NIR, MWIR, and LWIR to be used for surveillance, process control, and biomedical applications.
TERAHERTZ-BASED DETECTORS USING COLD-ATOM OPTICS
Authors: CROWNE FRANK J. , GOLDING WILLIAM M. , HAZELTON CLIFFORD
Published: October 2007

In this paper we explore the design of microwave-based structures that can enhance the interaction of electromagnetic fields with cold-atom ensembles, leading to novel sensing modalities based on the quantum-mechanical behavior of these systems. In particular, we discuss electromagnetically-induced transparency in a single uncondensed cold-atom cloud, and a two-cloud version of a SQUID, where the clouds are BEC's and take the place of the weakly coupled superconductors. These systems are both promising candidates for use in the high-precision detection of chemical contaminants.
DETECTION OF GASEOUS EFFLUENTS FROM AIRBORNE LWIR HYPERSPECTRAL IMAGERY USING PHYSICS-BASED SIGNATURES
Authors: MESSINGER DAVID W. , SALVAGGIO CARL , SINISGALLI NATALIE M.
Published: October 2007

Detection of gaseous effluent plumes from airborne platforms provides a unique challenge to the remote sensing community. The measured signatures are a complicated combination of phenomenology including effects of the atmosphere, spectral characteristics of the background material under the plume, temperature contrast between the gas and the surface, and the concentration of the gas. All of these quantities vary spatially further complicating the detection problem. In complex scenes simple estimation of a “residual” spectrum may not be possible due to the variability in the scene background. A common detection scheme uses a matched filter formalism to compare laboratory-measured gas absorption spectra with measured pixel radiances. This methodology can not account for the variable signature strengths due to concentration path length and temperature contrast, nor does it take into account measured signatures that are observed in both absorption and emission in the same scene. We have developed a physics-based, forward model to predict in-scene signatures covering a wide range in gas / surface properties. This target space is reduced to a set of basis vectors using a geometrical model of the space. Corresponding background basis vectors are derived to describe the non-plume pixels in the image. A Generalized Likelihood Ratio Test is then used to discriminate between plume and non-plume pixels. Several species can be tested for iteratively. The algorithm is applied to airborne LWIR hyperspectral imagery collected by the Airborne Hyperspectral Imager (AHI) over a chemical facility with some ground truth. When compared to results from a clutter matched filter the physics-based signature approach shows significantly improved performance for the data set considered here.
NONLINEAR CHEMICAL PLUME DETECTION USING KERNEL-BASED MATCHED SUBSPACE DETECTORS
Authors: KWON HEESUNG , NASRABADI NASSER M. , GILLESPIE PATTI
Published: October 2007

In this paper, we compare several detection algorithms that are based on spectral matched (subspace) filters. Nonlinear (kernel) versions of these spectral matched (subspace) detectors are also discussed and their performance is compared with the linear versions. These kernel-based detectors exploit the nonlinear correlations between the spectral bands that are ignored by the conventional detectors. Several well-known matched detectors, such as matched subspace detector, orthogonal subspace detector, spectral matched filter and adaptive subspace detector (adaptive cosine estimator) are extended to their corresponding kernel versions by using the idea of kernel-based learning theory. In kernel-based detection algorithms the data is implicitly mapped into a high dimensional kernel feature space by a nonlinear mapping which is associated with a kernel function. The detection algorithm is then derived in the feature space which is kernelized in terms of the kernel functions in order to avoid explicit computation in the high dimensional feature space. Experimental results based on simulated toy-examples and real hyperspectral imagery shows that the kernel versions of these detectors outperform the conventional linear detectors.
A QUASI-PASSIVE LEG EXOSKELETON FOR LOAD-CARRYING AUGMENTATION
Authors: WALSH CONOR JAMES , ENDO KEN , HERR HUGH
Published: October 2007

A quasi-passive leg exoskeleton is presented for load-carrying augmentation during walking. The exoskeleton has no actuators, only ankle and hip springs and a knee variable-damper. Without a payload, the exoskeleton weighs 11.7 kg and requires only 2 Watts of electrical power during loaded walking. For a 36 kg payload, we demonstrate that the quasi-passive exoskeleton transfers on average 80% of the load to the ground during the single support phase of walking. By measuring the rate of oxygen consumption on a study participant walking at a self-selected speed, we find that the exoskeleton slightly increases the walking metabolic cost of transport (COT) as compared to a standard loaded backpack (10% increase). However, a similar exoskeleton without joint springs or damping control (zero-impedance exoskeleton) is found to increase COT by 23% compared to the loaded backpack, highlighting the benefits of passive and quasi-passive joint mechanisms in the design of efficient, low-mass leg exoskeletons.
A PHYSIOLOGIST'S PERSPECTIVE ON ROBOTIC EXOSKELETONS FOR HUMAN LOCOMOTION
Authors: FERRIS DANIEL P. , SAWICKI GREGORY S. , DALEY MONICA A.
Published: October 2007

Technological advances in robotic hardware and software have enabled powered exoskeletons to move from science fiction to the real world. The objective of this article is to emphasize two main points for future research. First, the design of future devices could be improved by exploiting biomechanical principles of animal locomotion. Two goals in exoskeleton research could particularly benefit from additional physiological perspective: (i) reduction in the metabolic energy expenditure of the user while wearing the device, and (ii) minimization of the power requirements for actuating the exoskeleton. Second, a reciprocal potential exists for robotic exoskeletons to advance our understanding of human locomotor physiology. Experimental data from humans walking and running with robotic exoskeletons could provide important insight into the metabolic cost of locomotion that is impossible to gain with other methods. Given the mutual benefits of collaboration, it is imperative that engineers and physiologists work together in future studies on robotic exoskeletons for human locomotion.
UPPER LIMB POWERED EXOSKELETON
Authors: ROSEN JACOB , PERRY JOEL C.
Published: October 2007

An exoskeleton is a wearable robot with joints and links corresponding to those of the human body. With applications in rehabilitation medicine, virtual reality simulation, and teleoperation, exoskeletons offer benefits for both disabled and healthy populations. Analytical and experimental approaches were used to develop, integrate, and study a powered exoskeleton for the upper limb and its application as an assistive device. The kinematic and dynamic dataset of the upper limb during daily living activities was one among several factors guiding the development of an anthropomorphic, seven degree-of-freedom, powered arm exoskeleton. Additional design inputs include anatomical and physiological considerations, workspace analyses, and upper limb joint ranges of motion. Proximal placement of motors and distal placement of cable-pulley reductions were incorporated into the design, leading to low inertia, high-stiffness links, and back-drivable transmissions with zero backlash. The design enables full glenohumeral, elbow, and wrist joint functionality. Establishing the human-machine interface at the neural level was facilitated by the development of a Hill-based muscle model (myoprocessor) that enables intuitive interaction between the operator and the wearable robot. Potential applications of the exoskeleton as a wearable robot include (i) an assistive (orthotic) device for human power amplifications, (ii) a therapeutic and diagnostics device for physiotherapy, (iii) a haptic device in virtual reality simulation, and (iv) a master device for teleoperation.
"SOFT" EXOSKELETONS FOR UPPER AND LOWER BODY REHABILITATION — DESIGN, CONTROL AND TESTING
Authors: CALDWELL DARWIN G. , TSAGARAKIS N. G. , KOUSIDOU SOPHIA , COSTA NELSON , SARAKOGLOU IOANNIS
Published: October 2007

The basic concepts for exoskeletal systems have been suggested for some time with applications ranging from construction, manufacturing and mining to rescue and emergency services. In recent years, research has been driven by possible uses in medical/rehabilitation and military applications. Yet there are still significant barriers to the effective use and exploitation of this technology. Among the most pertinent of these factors is the power and actuation system and its impact of control, strength, speed and, perhaps most critically, safety. This work describes the design, construction and testing of an ultra low-mass, full-body exoskeleton system having seven degrees of freedom (DOFs) for the upper limbs and five degrees of freedom (DOFs) for each of the lower limbs. This low mass is primarily due to the use of a new range of pneumatic muscle actuators as the power source for the system. The work presented will show how the system takes advantage of the inherent controllable compliance to produce a unit that is powerful, providing a wide range of functionality (motion and forces over an extended range) in a manner that has high safety integrity for the user. The general layout of both the upper and the lower body exoskeleton is presented together with results from preliminary experiments to demonstrate the potential of the device in limb retraining, rehabilitation and power assist (augmentation) operations.
WHEN WERE ACTIVE EXOSKELETONS ACTUALLY BORN?
Authors: VUKOBRATOVIC MIOMIR K.
Published: October 2007

We are witnessing unimaginably intensive development in the field of humanoid robotics. The area of active exoskeletons is also experiencing a renaissance and is attracting increasing attention from researchers worldwide. The objective of this article is to consider the beginnings and review the history of the development of active exoskeletons, their original purpose and role in systems for rehabilitation of severely handicapped persons. The present-day development of active exoskeletons has to a large extent determined their future and applications in both the military and some specific activities that come out of the framework of rehabilitation systems and go deeply into special systems for enhancing power and expanding physical and working capabilities of humans. However, the origins of robotics, and especially of humanoid robotics, did not foreshadow such progress. We take a look back at the beginnings of the development of humanoid robots, especially bipedal locomotion systems and active exoskeletons, whose development marked the start of research in the domain of humanoid robotics. Once more we point out some of our pioneering results in the domain of active exoskeletons that were originally dedicated to supporting locomotion of handicapped persons. We show the relationships between the initial research in the field of active rehabilitation techniques and contemporary humanoid systems and try to predict the future directions of the development of humanoid robotics and active exoskeletal systems and their applications.
TNF-α increases protein content in C2C12and primary myotubes by enhancing protein translation via the TNF-R1, PI3K, and MEK
Authors: Plaisance Isabelle , Morandi Christian , Murigande Claire , Brink Marijke
Published: October 2007

Recent evidence supports that TNF-α, long considered a catabolic factor, may also have a physiological function in skeletal muscle. The catabolic view, mainly based on correlative studies in human and in vivo animal models, was challenged by experiments with myoblasts, in which TNF-α induced differentiation. The biological effects of TNF-α in differentiated muscle, however, remain poorly understood. In the present study, we tested whether TNF-α has growth-promoting effects in myotubes, and we characterized the mechanisms leading to these effects. Treatment of C2C12myotubes with TNF-α for 24 h increased protein synthesis (PS) and enhanced cellular dehydrogenase activity by 22 and 26%, respectively, without changing cell numbers. These effects were confirmed in myotubes differentiated from primary rat myoblasts. TNF-α activated two signaling cascades: 1) ERK1/2 and its target eIF4E and 2) Akt and its downstream effectors GSK-3, p70S6K, and 4E-BP1. TNF-α-induced phosphorylation of Akt, and ERK1/2 was inhibited by an antibody against TNF-α receptor 1 (TNF-R1). PD-98059 pretreatment abolished TNF-α-induced phosphorylation of ERK1/2 and eIF4E, whereas PS was only partially inhibited. LY-294002 completely abolished TNF-α-induced stimulation of PS as well as phosphorylation of Akt and its downstream targets GSK-3, p70S6K, and 4E-BP1. Rapamycin inhibited TNF-α-induced phosphorylation of the mTOR C1 target p70S6Kwithout altering TNF-α-induced PS and 4E-BP1 phosphorylation. In conclusion, our results provide evidence that TNF-α enhances PS in myotubes and that this is based on enhanced protein translation mediated by the TNF-R1 and PI3K-Akt and MEK-ERK signaling cascades.
Repeated resistance exercise training induces different changes in mRNA expression of MAFbx and MuRF-1 in human skeletal muscle
Authors: Mascher Henrik , Tannerstedt Jörgen , Brink-Elfegoun Thibault , Ekblom Björn , Gustafsson Thomas , Blomstrand Eva
Published: October 2007

The gain in muscle mass as a result of resistance training is dependent on changes in both anabolic and catabolic reactions. A frequency of two to three exercise sessions per week is considered optimal for muscle gain in untrained individuals. Our hypothesis was that a second exercise session would enlarge the anabolic response and/or decrease the catabolic response. Eight male subjects performed resistance exercise on two occasions separated by 2 days. Muscle biopsies were taken from the vastus lateralis before and 15 min, 1 h, and 2 h after exercise. Exercise led to severalfold increases in phosphorylation of mTOR at Ser2448, p70 S6 kinase (p70S6k) at Ser424/Thr421 and Thr389, and ribosomal protein S6, which persisted for up to 2 h of recovery on both occasions. There was a tendency toward a larger effect of the second exercise on p70S6k and S6, but the difference did not reach statistical significance. The mRNA expression of MuRF-1, which increased after exercise, was 30% lower after the second exercise session than after the first one. MAFbx expression was not altered after exercise but downregulated 30% 48 h later, whereas myostatin expression was reduced by 45% after the first exercise and remained low until after the second exercise session. The results indicate that 1) changes in expression of genes involved in protein degradation are attenuated as a response to repetitive resistance training with minor additional increases in enzymes regulating protein synthesis and 2) the two ubiquitin ligases, MuRF-1 and MAFbx, are differently affected by the exercise as well as by repeated exercise.
Penile erection and micturition events triggered by electrical stimulation of the mesopontine tegmental area
Authors: Salas Juan Carlos Toledo , Iwasaki Hiroshi , Jodo Eiichi , Schmidt Markus H. , Kawauchi Akihiro , Miki Tsuneharu , Kayama Yukihiko , Otsuki Manabu , Koyama Yoshimasa
Published: October 2007

The cholinergic neurons in the laterodorsal tegmental nucleus (LDT) play a crucial role in the regulation of rapid eye movement (REM) sleep. Because penile erection occurs during REM sleep, the involvement of the LDT in penile erection was examined in unanesthetized head-restrained rats. To detect penile erection, corpus spongiosum of the penis (CSP) pressure was measured through a telemetric device with simultaneous bulbospongiosum (BS) muscle EMG recording through stainless wires. Electrical stimulation in and around the LDT induced the following three CSP pressure patterns: 1) a full erection pattern indistinguishable from the nonevoked or spontaneous erection, characterized by a slow increase in CSP pressure with additional sharp CSP peaks associated with BS muscle bursts, 2) a muscular pattern characterized by sharp CSP pressure peaks but in the absence of a vascular component, i.e., without an increase in baseline CSP pressure, and 3) a mixed-type response characterized by high-frequency CSP pressure peaks followed by a full erection response. Full erections were evoked in and around the LDT, including more medially and ventrally. The sites for inducing mixed-type events were intermingled with the sites that triggered full erections in the anterior half of the LDT, whereas they were separated in the posterior half. The sites for muscular responses were lateral to the sites for full erections. Finally, a CSP pressure response identical to micturition was evoked in and around the Barrington's nucleus and in the dorsal raphe nucleus. These results suggest that the LDT and surrounding region are involved in the regulation of penile erection. Moreover, different anatomical areas in the mesopontine tegmentum may have specific roles in the regulation of penile erection and micturition.
Marsupial uncoupling protein 1 sheds light on the evolution of mammalian nonshivering thermogenesis
Authors: Jastroch M. , Withers K. W. , Taudien S. , Frappell P. B. , Helwig M. , Fromme T. , Hirschberg V. , Heldmaier G. , McAllan B. M. , Firth B. T. , Burmester T. , Platzer M. , Klingenspor M.
Published: October 2007

Brown adipose tissue expressing uncoupling protein 1 (UCP1) is responsible for adaptive nonshivering thermogenesis giving eutherian mammals crucial advantage to survive the cold. The emergence of this thermogenic organ during mammalian evolution remained unknown as the identification of UCP1 in marsupials failed so far. Here, we unequivocally identify the marsupial UCP1 ortholog in a genomic library of Monodelphis domestica. In South American and Australian marsupials, UCP1 is exclusively expressed in distinct adipose tissue sites and appears to be recruited by cold exposure in the smallest species under investigation ( Sminthopsis crassicaudata). Our data suggest that an archetypal brown adipose tissue was present at least 150 million yr ago allowing early mammals to produce endogenous heat in the cold, without dependence on shivering and locomotor activity.
Interference of globin genes with biomarker discovery for allograft rejection in peripheral blood samples
Authors: Li Li , Ying Lihua , Naesens Maarten , Xiao Wenzhong , Sigdel Tara , Hsieh Sue , Martin Jon , Chen Rong , Liu Kang , Mindrinos Michael , Davis Ron , Sarwal Minnie
Published: October 2007

Microarray technology is a powerful tool in the discovery of new biomarkers for disease. After solid organ transplantation, where the detection of rejection is usually made on invasive biopsies, it could be hypothesized that noninvasive transcriptional profiling of peripheral blood will reveal rejection-specific expression patterns from circulating immune cells. However, in kidney transplant rejection, the analysis of gene expression data in whole blood has proven difficult for detecting significant genes specific for acute graft rejection. Previous studies have demonstrated that the abundance of globin genes in whole blood may mask the underlying biological differences between whole blood samples. In the present study, we compared the gene expression profiles of peripheral blood of nine stable renal allograft recipients with seven matched patients having an ongoing acute renal transplant rejection, using four different protocols of preparation, amplification, and synthesis of cRNA or cDNA and hybridization on the Affymetrix platform. We demonstrated that the globin reduction method is not sufficient to unmask clinically relevant rejection-specific transcriptome profiles in whole blood. Applying an additional mathematical depletion of the globin genes improves the efficacy of globin reduction but cannot remove the confounding influence of globin gene hybridization. Sampling of peripheral blood leukocytes alone, without the confounding influence of globin mRNA, provides sensitive and specific peripheral signatures for graft rejection, with many of these signals overlapping with rejection-driven tissue (kidney)-specific signatures from matched biopsies. Similar applications may exist for array-based biomarker discovery for other diseases associated with changes in leukocyte trafficking, activation, or function.
Hybrid Modelling and Dynamical Analysis of Gene Regulatory Networks with Delays
Authors: Ahmad Jamil , Bernot Gilles , Comet Jean-Paul , Lime Didier , Roux Olivier
Published: October 2007

René Thomas’ discrete modelling of gene regulatory networks (GRN) is a well-known approach to study the dynamics resulting from a set of interacting genes. It deals with some parameters which reflect the possible targets of trajectories. Those parameters are a priori unknown, but they may generally be deduced from a well-chosen set of biologically observed trajectories. Besides, it neglects the time delays for a gene to pass from one level of expression to another one. The purpose of this paper is to show that we can account for time delays of increasing or decreasing expression levels of genes in a GRN, while preserving powerful enough computer-aided reasoning capabilities. We designed a more accurate abstraction of GRN where delays are now supposed to be non-null unknown new parameters. We show that such models, together with hybrid model-checking algorithms, make it possible to obtain some results about the behaviour of a network of interacting genes, since dynamics depend on the respective values of the parameters. The characteristic of our approach is that, among possible execution trajectories in the model, we can automatically find out both viability cycles and absorption in capture basins. As a running example, we show that we are able to discriminate between various possible dynamics of mucus production in the bacterium Pseudomonas aeruginosa.
Development of a Conversion Factor to Facilitate Comparison of National Institute of Health Stroke Scale Scores with Scandinavian Stroke Scale Scores
Authors: Ali Khalid , Cheek Elizabeth , Sills Sheila , Crome Peter , Roffe Christine
Published: October 2007

Background: The National Institute of Health Stroke Scale (NIHSS) and the Scandinavian Stroke Scale (SSS) are commonly used in clinical stroke trials. Use of different scales in trials makes comparison of outcomes difficult. Methods: Adult patients with an acute stroke were recruited within 24 h of onset, and NIHSS, SSS and Glasgow Coma Scale scores were assessed at baseline and repeated at 1 week. Results and Conclusions: A total of 144 patients were included (46% males, mean age = 73 years). At presentation the median SSS score was 38 (2–58), and a week later 40 (4–58), the median NIHSS score at presentation was 5 (0–29) and a week later 3 (0–27). Changes in both scales were strongly correlated, r = 0.76, p < 0.001. Both were good predictors of mortality. Linear regression analysis produced an equation relating the two: SSS = 50 – 2 × NIHSS.