Search results for "efficient"

Protein isotope effects in dihydrofolate reductase from Geobacillus stearothermophilus show entropic-enthalpic compensatory effects on the rate const…

2014

Catalysis by dihydrofolate reductase from the moderately thermophilic bacterium Geobacillus stearothermophilus (BsDHFR) was investigated by isotope substitution of the enzyme. The enzyme kinetic isotope effect for hydride transfer was close to unity at physiological temperatures but increased with decreasing temperatures to a value of 1.65 at 5 °C. This behavior is opposite to that observed for DHFR from Escherichia coli (EcDHFR), where the enzyme kinetic isotope effect increased slightly with increasing temperature. These experimental results were reproduced in the framework of variational transition-state theory that includes a dynamical recrossing coefficient that varies with the mass of…

Drying of shrinking cylinder-shaped bodies

1998

Abstract A mathematical model has been developed for the prediction of sample temperature, average moisture and moisture distribution in a cylinder-shaped solid during the drying process. The effect of shrinkage was taken into account. The macroscopic heat balance and the microscopic mass balance combined with Fick's law were simultaneously solved using the Runge-Kutta-Merson method and a numerical finite difference method. The effective diffusion coefficient was expressed as a function of sample temperature and local moisture content. Using an experimental drying curve determined at 90 °C, the diffusional equation was identified for broccoli stems, and was used to predict the average and l…

Demixing of Mixed Micelles. Thermodynamics of Sodium Perfluorooctanoate−Sodium Dodecanoate Mixtures in Water

1997

Conductivity, density, heat capacity, enthalpy of dilution, and osmotic coefficient measurements of water−sodium perfluorooctanoate (NaPFO)−sodium dodecanoate systems were carried out as functions of the surfactants' total molality (mt) at different mole fractions (XNaPFO). From conductivity data, the critical micelle concentration (cmc) and the degree of ionization (β) of the micelles were derived. The cmc's of the micelles are higher than those of the pure surfactants while β depends linearly on XNaPFO. At a given mole fraction, the apparent molar volume (VΦ) and heat capacity (CΦ) of the mixture increases and decreases monotonically with mt, respectively. From data in the premicellar reg…

Thermodynamic Studies of Sodium Dodecyl Sulfate–Sodium Dodecanoate Mixtures in Water

1996

Abstract Conductivity, density, heat capacity, enthalpy of dilution, and osmotic coefficient measurements of water–sodium dodecyl sulfate (NaDS)–sodium dodecanoate systems were carried out as functions of the surfactants total molality ( m t ) at different mole fractions ( X NaDS ). From conductivity data, the critical micelle concentration (cmc) and the degree of ionization of the micelles (β) were calculated. The cmc vs X NaDS profile deviates negatively from that predicted on the basis of the Clint approach, while the β vs X NaDS profile deviates positively from the line correlating the values for pure surfactants. At a given mole fraction, the profiles of all the investigated properties…

Molecular characterization of α,β-poly[( N -hydroxyethyl)- dl –aspartamide] by light scattering and viscometry studies

2000

Abstract α,β-poly[(N-hydroxyethyl)- dl -aspartamide] (PHEA) is a new synthetic polymer which is of interest in biomedical applications. In this paper, the molecular characterization of PHEA by multi-angle laser light scattering and viscometry off-line and on-line to a size exclusion chromatography system is reported. These techniques furnish an exhaustive and consistent characterization of the PHEA polymer. The fractionation of the PHEA macromolecules was relatively simple. Using an aqueous mobile phase of medium ionic strength, the elution was substantially regular and the macromolecules were not aggregate. The molar mass M of four PHEA samples approximately ranges from 46 to 53 K g/mol, t…

Six-month healing success rates after endodontic treatment using the novel GentleWave System: the pure prospective multi-center clinical study

2015

Background This prospective multi-center (PURE) clinical study evaluated healing rates for molars after root canal treatment employing the GentleWave® System (Sonendo, Inc., Laguna Hills, CA). Material and Methods Eighty-nine patients met the inclusion criteria and consented for this clinical study after referral for a root canal treatment. All enrolled patients were treated with the GentleWave System. Five endodontists performed the clinical procedures and follow-up evaluations. Pre-operative, intra-operative, and post-operative data were collected from the consented patients. Each patient was evaluated for clinical signs and symptoms. Two trained, blinded, and independent evaluators score…

Assessing and mapping multi-hazard risk susceptibility using a machine learning technique

2020

AbstractThe aim of the current study was to suggest a multi-hazard probability assessment in Fars Province, Shiraz City, and its four strategic watersheds. At first, we construct maps depicting the most effective factors on floods (12 factors), forest fires (10 factors), and landslides (10 factors), and used the Boruta algorithm to prioritize the impact of each respective factor on the occurrence of each hazard. Subsequently, flood, landslides, and forest fire susceptibility maps prepared using a Random Forest (RF) model in the R statistical software. Results indicate that 42.83% of the study area are not susceptible to any hazards, while 2.67% of the area is at risk of all three hazards. T…

2020

Purpose To investigate short-term training and recovery-related effects on heart rate during a standardized submaximal running test. Methods Ten elite badminton players (7 females and 3 males) were monitored during a 12-week training period in preparation for the World Championships. Exercise heart rate (HRex) and perceived exertion were measured in response to a 5-min submaximal shuttle-run test during the morning session warm-up. This test was repeatedly performed on Mondays after 1–2 days of pronounced recovery (‘recovered’ state; reference condition) and on Fridays following 4 consecutive days of training (‘strained’ state). In addition, the serum concentration of creatine kinase and u…

Multivariate approach to reveal relationships between sensory perception of cheeses and aroma profile obtained with different extraction methods

2014

A new and original statistical approach was used to compare the effectiveness of 4 different methods to analyse aroma compounds of seven different commercial semi-hard cheeses with regard to their orthonasal sensory perception. Four extraction methods were evaluated: Purge and Trap, Artificial Mouth, Solid-Phase Microextraction (SPME) and Solvent-Assisted Flavour Evaporation (SAFE). Among the headspace methods, Artificial Mouth gave the closest representation of the studied product space to the sensory perception one. The SAFE method was complementary to the dynamic headspace methods, as it was very efficient in extracting the heavy molecules but less efficient for extracting the most volat…

Evaluation of ergonomic factors and postures that cause muscle pains in dentistry students’ bodies

2015

Background: Work-related musculoskeletal disorders commonly experienced by dental professionals are one of the main occupational health problem affecting their health and well-being.This study was conducted to evaluate ergonomic factors and profession-related postures and also investigate relationship between demographic factors and work condition with pain in dental students. Material and Methods: 60 freshman and sophomore dentistry students were randomly chosen as the subjects of control group, and 60 of 5th and 6th-year students were selected as the members of exposure group. Data related to the subjects such as sex, doing exercise, severity of musculoskeletal pain were obtained through …