Energy Parameters (energy + parameter)

Distribution by Scientific Domains


Selected Abstracts


On-line size measurement of yeast aggregates using image analysis

BIOTECHNOLOGY & BIOENGINEERING, Issue 2 2001
Sandrine Mas
Abstract Alcohol fermentation productivity can be strongly improved using a flocculation-based yeast recycle. However, the efficiency of the biomass retention system depends strongly on the yeast particle size. Accordingly, the monitoring and control of yeast floc diameter are of primary importance. The on-line measurement of mean floc diameter has been achieved using on-line image analysis, based on the evaluation of image texture. The texture analysis method consisted in the building of a co-occurrence matrix from which the so-called "Energy parameter" was extracted. While image texture is usually used for classification purposes, it has been used here as a quantitative descriptor: a correlation has been found between this statistical image feature and off-line manual floc-size determinations. In the floc-size range investigated (|bu 0.5,4.3 mm), the evaluated mean diameter was in good agreement with the actual particle size, with a determination coefficient equal to 0.980. In contrast with manual measurements, slow and tedious, this method gave the value of the mean particle diameter in real-time, without sampling. This novel tool has been used to investigate the behavior of yeast aggregates as a function of fermentation conditions. While biomass concentration was kept constant, step increases of the feed rate led to a decrease of the mean floc diameter. Image analysis showed that the particle-size reduction could occur within a few minutes after modification of the medium dilution rate, demonstrating the disruptive effect of the CO2 efflux. The kinetic of aggregate formation was dependent on the gas-phase composition. Instead of recycling fermentation gas, sparging the fermentor with nitrogen, to reduce dissolved CO2 concentration, increased the rate of floc-size growth. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 91,98, 2001. [source]


46 The feasibility of duodenum electrical stimulation to produce gastrointestinal symptoms in a clinical trial

NEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2006
KA STECCO
Introduction:, Proximal duodenal electrical stimulation with various energy parameters has been investigated as a possible treatment for various gastrointestinal (GI) myoelectrical diseases. Wide pulse width (millisecond) stimulation in the proximal duodenum can disrupt or entrain the normal myoelectrical rhythm and provide a potential feedback pathway to alter normal gastric function such as emptying, fundus tone, and intra-gastric pressure and subsequently produce specific symptoms that could affect eating behaviors. A specific level of electrical stimulation is necessary to elicit symptoms and serve as an indicator that energy parameters are adequate. However, there has been no published data correlating electrical threshold stimulation with symptom characterization. The goal of this study was to determine the average minimum pulse width necessary to elicit GI symptoms. Methods:, Eight patients underwent endoscopic placement of intraluminal electrodes in the proximal duodenum. Each patient received electrical stimulation in the millisecond (ms) range starting with a pulse width of 100 ms that was increased by intervals of 100 ms up to a maximum pulse width of 500 ms. The pulse repetition frequency was fixed at 12 CPM and each regimen was repeated for amplitudes ranging from 2 milliamps (mA) to 10 mA. Gastrointestinal symptom scores consisting of nausea, vomiting, satiety, fullness, pain, bloating and other, were taken at baseline and after each regimen change. Results:, There was an average minimum threshold necessary for elicitation of symptoms (293.7 + 41.7 ms, p-value = 0.063). The three most frequently reported GI symptoms were crampy abdominal pain, fullness, and bloating. Conclusions:, Electrical stimulation of the duodenum is feasible. A certain minimum threshold of duodenal electrical stimulation is necessary to elicit GI symptoms in patients. The intensity and patient tolerability of each specific GI symptom was able to be adjusted by changing a certain energy parameter within a regimen. Further research is warranted to evaluate the ability of duodenal electrical stimulation to produce GI symptoms that may alter eating behaviors. [source]


Molecular dynamics study on effects of surface structures in nanometer scale on energy transfer from fluid to surface

HEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 3 2005
Masahiko Shibahara
Abstract Energy transfer from fluid to surface was calculated numerically by using the classical molecular dynamics method in order to investigate the effects of surface structures from 0.1 nm to 10 nm on surface energy transfer. Surface structures on a constant surface area were composed of several hundred atoms having various potential energy parameters, in other words, thermal properties. The upper region in the calculation domain was controlled at a constant temperature and one of the solid atomic layers at the lower region in the calculation domain was controlled at another constant temperature to create a temperature gradient in the calculation system. Energy transfer to the surface was very dependent on surface nanometer scale structures in that affected the static structure and the dynamic behaviors of fluid molecules in the vicinity of the surface. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(3): 171,179, 2005; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/htj.20055 [source]


Pulsed Signal Therapy® for the treatment of musculoskeletal conditions: a millennium paradigm

INTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 3 2004
Richard MARKOLL
Abstract Reports and reviews from various sources, including the World Health Organization and United Nations Population Division, confirm the general increasing trend in the ageing population groups worldwide. There are over 150 types of musculoskeletal conditions, with rheumatoid arthritis, osteoarthritis, osteoporosis, low back pain and limb trauma, accounting for the greatest impact on the population at large. Osteoarthritis (OA) is predicted to become the fourth leading cause of disability by the year 2020. The most common medication prescribed for OA is non-steroidal anti-inflammatory drugs (NSAIDs). These have long been associated with numerous adverse effects, are costly and short-term in their ,therapeutic' effect. Pulsed Signal Therapy® (PSTÔ) is an innovative treatment modality for musculoskeletal conditions. It has been commercially available since 1992, is currently employed in at least 800 clinics and/or medical institutes, and to-date, no adverse effects have been reported. Furthermore, it is non-invasive, non-pharmacological, painless, with long-term follow-up, and sustained efficacy. When connective tissue is injured and physiological signalling is disturbed or absent, PSTÔ, as the external, biophysical signal (stimulus) of physiological energy parameters and waveform, passively induces ,fluid flow' in the injured area, creating ,streaming potentials', that induce biophysical-biochemical coupling, subsequent signal transduction, to activate repair and regenerative processes. In doing so, it restores the innate, physiological signalling to enable these regenerative and repair processes to continue naturally. [source]


Molecular dynamics simulation in the grand canonical ensemble

JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 10 2007
Hossein Eslami
Abstract An extended system Hamiltonian is proposed to perform molecular dynamics (MD) simulation in the grand canonical ensemble. The Hamiltonian is similar to the one proposed by Lynch and Pettitt (Lynch and Pettitt, J Chem Phys 1997, 107, 8594), which consists of the kinetic and potential energies for real and fractional particles as well as the kinetic and potential energy terms for material and heat reservoirs interacting with the system. We perform a nonlinear scaling of the potential energy parameters of the fractional particle, as well as its mass to vary the number of particles dynamically. On the basis of the equations of motion derived from this Hamiltonian, an algorithm has been proposed for MD simulation at constant chemical potential. The algorithm has been tested for the ideal gas, for the Lennard,Jones fluid over a wide range of temperatures and densities, and for water. The results for the low-density Lennard,Jones fluid are compared with the predictions from a truncated virial equation of state. In the case of the dense Lennard,Jones fluid and water our predicted results are compared with the results reported using other available methods for the calculation of the chemical potential. The method is also applied to the case of vapor-liquid coexistence point predictions. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007 [source]


MOPED: Method for optimizing physical energy parameters using decoys

JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 1 2003
Chaok Seok
Abstract We present a method called MOPED for optimizing energetic and structural parameters in computational models, including all-atom energy functions, when native structures and decoys are given. The present method goes beyond previous approaches in treating energy functions that are nonlinear in the parameters and continuous in the degrees of freedom. We illustrate the method by improving solvation parameters in the energy function EEF1, which consists of the CHARMM19 polar hydrogen force field augmented by a Gaussian solvation term. Although the published parameters for EEF1 correctly discriminate the native from decoys in the decoy sets of Levitt et al., they fail on several of the more difficult decoy sets of Baker et al. MOPED successfully finds improved parameters that allow EEF1 to discriminate native from decoy structures on all protein structures that do not have metals or prosthetic groups. © 2002 Wiley Periodicals, Inc. J Comput Chem 24: 89,97, 2003 [source]


Evaluation of a rotary tablet press simulator as a tool for the characterization of compaction properties of pharmaceutical products

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2010
F. Michaut
Abstract The Stylcam 100R, a rotary press simulator, was designed to simulate speed profiles of rotary tablet presses. Such a simulator was qualified by numerous laboratories and, actually, its ability to be used for studying the behaviour of powders under pressure should be examined. Then, the purpose of this work was to investigate the performances of the Stylcam 100R for characterizing the compaction behaviour and the tabletting properties of pharmaceutical powders. The compressibility of three pharmaceutical excipients (microcrystalline cellulose, dicalcium phosphate dihydrate and ,-lactose monohydrate) was studied. Four compression speeds were used on the compaction simulator. Force,displacement cycles were associated with two energy parameters, the specific total energy (Estot) and the specific expansion energy (Esexp). The mean yield pressure was calculated from Heckel's plots obtained with the in-die method. The diametral tensile strength of compacts was measured in order to evaluate mechanical properties. To evaluate the accuracy of all these parameters, a comparative study was carried out on an eccentric instrumented press. The values of energy parameters and tensile strengths of tablets are close between the eccentric press and the compaction simulator, whatever the compression speed on the latter. The mean yield pressure values obtained using the two presses are different. Finally, the Stylcam 100R seems to be a good tool for characterising tabletting properties of powders, except for the Heckel's model probably due to an unadapted equation of deformation and a lack of accuracy of the displacement transducers. Future improvements should allow correcting these two points. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 2874,2885, 2010 [source]


Thermodynamic Reassessment of ZrO2,CaO System

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2009
Kun Wang
In this work, several thermodynamic assessments adopted widely for ZrO2,CaO system are reviewed and examined, the existing discrepancies are summarized, and a new assessment is carried out based on the formation enthalpy of two compounds (CaZr4O9 and Ca6Zr19O44) and experimental activity data concerning cubic solid solution. The thermodynamic parameters of all phases have been optimized by the least squares minimization procedure, a self consistent set of the optimized Gibbs energy parameters has been derived, which can be safely used to extrapolate into the multicomponent system. Compared with experimental data and the results in this work as well as the results reported previously, it is demonstrated that the present thermodynamic assessment is in better agreement with most of the experiments. [source]


Ex vivo and in vivo evaluation of laser-induced thermotherapy for nodular thyroid disease

LASERS IN SURGERY AND MEDICINE, Issue 7 2009
Jörg-P.
Abstract Background and Objective The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like laser-induced thermotherapy (LITT) are increasingly used to treat tumors of parenchymatous organs and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose,response relationship for LITT of thyroid nodules. Materials and Methods Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n,=,110) and in vivo (n,=,10) using an Nd:YAG laser (1,064,nm). Laser energy was applied for 300,seconds in a power range of 10,20,W. During the ablation, continuous temperature measurement at a distance of 5 and 10,mm from the applicator was performed. The lesions were longitudinally and transversally measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed. Results The maximum inducible lesion volumes were between 0.74,±,0.18,cm3 at a laser power of 10,W and 3.80,±,0.41,cm3 at 20,W. The maximum temperatures after ablation were between 72.9,±,2.9°C (10,W) and 112.9,±,9.2°C (20,W) at a distance of 5,mm and between 49.5,±,2.2°C (10,W) and 73.2,±,6.7°C (20,W) at a distance of 10,mm from the applicator. The histochemical analysis demonstrates a complete loss of NADPH dehydrogenase activity in thermal lesions as a sign of irreversible cell damage. Conclusions This study is the first to demonstrate a dose,response relationship for LITT of thyroid tissue. LITT is suitable for singular thyroid nodules and induces reproducible clinically relevant lesions with irreversible cell damage in an appropriate application time. Lasers Surg. Med. 41:479,486, 2009. © 2009 Wiley-Liss, Inc. [source]


Photometric redshifts for weak lensing tomography from space: the role of optical and near infrared photometry

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2008
F. B. Abdalla
ABSTRACT We study in detail the photometric redshift requirements needed for tomographic weak gravitational lensing in order to measure accurately the dark energy equation of state. In particular, we examine how ground-based photometry (u, g, r, i, z, y) can be complemented by space-based near-infrared (near-IR) photometry (J, H), e.g. onboard the planned DUNE satellite. Using realistic photometric redshift simulations and an artificial neural network photo- z method we evaluate the figure of merit for the dark energy parameters (w0, wa). We consider a DUNE -like broad optical filter supplemented with ground-based multiband optical data from surveys like the Dark Energy Survey, Pan-STARRS and LSST. We show that the dark energy figure of merit would be improved by a factor of 1.3,1.7 if IR filters are added onboard DUNE. Furthermore we show that with IR data catastrophic photo- z outliers can be removed effectively. There is an interplay between the choice of filters, the magnitude limits and the removal of outliers. We draw attention to the dependence of the results on the galaxy formation scenarios encoded into the mock galaxies, e.g. the galaxy reddening. For example, very deep u -band data could be as effective as the IR. We also find that about 105,106 spectroscopic redshifts are needed for calibration of the full survey. [source]


46 The feasibility of duodenum electrical stimulation to produce gastrointestinal symptoms in a clinical trial

NEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2006
KA STECCO
Introduction:, Proximal duodenal electrical stimulation with various energy parameters has been investigated as a possible treatment for various gastrointestinal (GI) myoelectrical diseases. Wide pulse width (millisecond) stimulation in the proximal duodenum can disrupt or entrain the normal myoelectrical rhythm and provide a potential feedback pathway to alter normal gastric function such as emptying, fundus tone, and intra-gastric pressure and subsequently produce specific symptoms that could affect eating behaviors. A specific level of electrical stimulation is necessary to elicit symptoms and serve as an indicator that energy parameters are adequate. However, there has been no published data correlating electrical threshold stimulation with symptom characterization. The goal of this study was to determine the average minimum pulse width necessary to elicit GI symptoms. Methods:, Eight patients underwent endoscopic placement of intraluminal electrodes in the proximal duodenum. Each patient received electrical stimulation in the millisecond (ms) range starting with a pulse width of 100 ms that was increased by intervals of 100 ms up to a maximum pulse width of 500 ms. The pulse repetition frequency was fixed at 12 CPM and each regimen was repeated for amplitudes ranging from 2 milliamps (mA) to 10 mA. Gastrointestinal symptom scores consisting of nausea, vomiting, satiety, fullness, pain, bloating and other, were taken at baseline and after each regimen change. Results:, There was an average minimum threshold necessary for elicitation of symptoms (293.7 + 41.7 ms, p-value = 0.063). The three most frequently reported GI symptoms were crampy abdominal pain, fullness, and bloating. Conclusions:, Electrical stimulation of the duodenum is feasible. A certain minimum threshold of duodenal electrical stimulation is necessary to elicit GI symptoms in patients. The intensity and patient tolerability of each specific GI symptom was able to be adjusted by changing a certain energy parameter within a regimen. Further research is warranted to evaluate the ability of duodenal electrical stimulation to produce GI symptoms that may alter eating behaviors. [source]


An energy algorithm improves symptoms in some patients with gastroparesis and treated with gastric electrical stimulation

NEUROGASTROENTEROLOGY & MOTILITY, Issue 4 2006
N. Abidi
Abstract, Gastric electrical stimulation (GES) is effective to improve symptoms of nausea and vomiting in most patients, but very little is known about the effect of varying stimulation parameters. We analysed stimulation parameters in a pilot study of 22 patients (12 idiopathic, four diabetic and four postsurgical) with drug-refractory gastroparesis who did not respond optimally to initial settings. Patients underwent high-frequency/lowenergy GES using identical initial stimulation parameters: 5 mA of current, 330 ,s pulse width, 14 Hz for 0.1 s on and 5.0 s off. Due to lack on optimal response, 22 patients underwent alteration of an algorithm using stimulation parameters. At follow-up (mean of 4.3 years) a dose,response relationship for charge, power and energy were compared with baseline for the whole group and for each diagnostic subgroup by anovadata are reported as mean ± SE. Based on the mean of individual dose,response curves, differences in data are charge, current per pulse and energy per pulse were noted for the whole group at follow up vs baseline. The subgroup of patients with postsurgical gastroparesis required the most energy using the algorithm. In conclusion, an algorithmic approach to identify optimal stimulation parameters in GES for individual patients is associated with symptom improvement. Also, certain subgroups appear to have different energy parameters. Based on this preliminary data, the use of an algorithm for some patients with GES is feasible and may have potential for clinical application. A randomized-controlled trial of different stimulation parameters for GES seems warranted. [source]


Amino acid interaction preferences in proteins

PROTEIN SCIENCE, Issue 3 2010
Anupam Nath Jha
Abstract Understanding the key factors that influence the interaction preferences of amino acids in the folding of proteins have remained a challenge. Here we present a knowledge-based approach for determining the effective interactions between amino acids based on amino acid type, their secondary structure, and the contact based environment that they find themselves in the native state structure as measured by their number of neighbors. We find that the optimal information is approximately encoded in a 60 × 60 matrix describing the 20 types of amino acids in three distinct secondary structures (helix, beta strand, and loop). We carry out a clustering scheme to understand the similarity between these interactions and to elucidate a nonredundant set. We demonstrate that the inferred energy parameters can be used for assessing the fit of a given sequence into a putative native state structure. [source]


Two-state vs. multistate protein unfolding studied by optical melting and hydrogen exchange

PROTEIN SCIENCE, Issue 10 2000
Leland Mayne
Abstract A direct conflict between the stabilization free energy parameters of cytochrome c determined by optical methods and by hydrogen exchange (HX) is quantitatively explained when the partially folded intermediates seen by HX are taken into account. The results support the previous HX measurements of intermediate populations, show how intermediates can elude the standard melting analysis, and illustrate how they confuse the analysis when they are significantly populated within the melting transition region. [source]


Parallax measurements on cosmological scales

ASTRONOMY & GEOPHYSICS, Issue 3 2009
Article first published online: 29 MAY 200
Research Notes The prospect of advanced astrometric satellites raises the tantalizing possibility that we will be able to make astrometric measurements at such a precision as to place constraints on dark energy parameters. That is the premise outlined by Fiona Ding and Rupert Croft of Carnegie Mellon University, Pittsburgh, USA, in Monthly Notices of the Royal Astronomical Society, [source]