Microstructure and chemistry affects apatite nucleation on calcium phosphate bone graft substitutes

The bioactivity of calcium phosphate bone grafts of varying chemistry and strut-porosity was compared by determining the rate of formation of hydroxycarbonate apatite crystals on the material surface after being soaked in simulated body fluid for up to 30 days. Three groups of silicate-substituted hydroxyapatite material were tested, with each group comprising a different quantity of strut-porosity (23, 32, and 46 % volume). A commercially available porous β-tricalcium phosphate bone graft substitute was tested for comparison. Results indicate that strut-porosity of a material affects the potential for formation of a precursor to bone-like apatite and further confirms previous findings that β-tricalcium phosphate is less bioactive than hydroxyapatite.     

A line scanning confocal fluorescent microscope using a CMOS rolling shutter as an adjustable aperture

Traditional confocal microscopy uses a physical aperture barrier to prevent out-of-focus light from reaching the detector. The physical nature of a conventional aperture limits control over the system confocality. We describe a new line scanning confocal microscope that eliminates a need for a physical aperture by employing a software-controllable rolling shutter on a CMOS camera. A confocal image is obtained by synchronizing motion of the rolling shutter and the laser line scanning over a sample. Confocal resolution of this microscope is adjustable in real time and independently established for each fluorescence channel by changing the rolling shutter width. This technology has been implemented in the IN Cell Analyzer 6000 system by GE Healthcare.     

The Team Role Test: Development and validation of a team role knowledge situational judgment test.

The main objectives in this research were to introduce the concept of team role knowledge and to investigate its potential usefulness for team member selection. In Study 1, the authors developed a situational judgment test, called the Team Role Test, to measure knowledge of 10 roles relevant to the team context. The criterion-related validity of this measure was examined in 2 additional studies. In a sample of academic project teams (N = 93), team role knowledge predicted team member role performance (r = .34). Role knowledge also provided incremental validity beyond mental ability and the Big Five personality factors in the prediction of role performance. The results of Study 2 revealed that the predictive validity of role knowledge generalizes to team members in a work setting (N = 82, r = .30). The implications of the results for selection in team environments are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interdisciplinary approaches to job design: A constructive replication with extensions.

This study replicated Campion and Thayer's (1985) research, which drew from many disciplines (e.g., psychology, engineering, human factors, physiology) to demonstrate four approaches to job design and their corresponding outcomes: motivational approach with satisfaction outcomes, mechanistic approach with efficiency outcomes, biological approach with comfort outcomes, and perceptual/motor approach with reliability outcomes. This study extended the research in five ways. First, it used an expanded sample of 92 jobs and 1,024 respondents from a different industry. Second, a self-report measure was developed and evaluated, because many jobs cannot be analyzed observationally. Third, method bias was addressed by not finding evidence of priming effects, by demonstrating strong relationships even when within-subject bias was avoided, and by relating job design to independent opinion survey data. Fourth, reliability of aggregate responses was demonstrated, and relationships at the job level of analysis were larger than at the individual level. Fifth, neither individual differences in terms of preferences/tolerances for types of work nor demographics moderated job design–outcome relationships. It was concluded that different approaches to job design influence different outcomes, each approach has costs as well as benefits, trade-offs may be needed, and both theory and practice must be interdisciplinary in perspective. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Health care utilization in multiple sclerosis: a population-based study in Olmsted County, MN

OBJECTIVE: The authors sought to determine acute ambulatory- and hospital-billed charges for the Olmsted County, Minnesota Multiple Sclerosis (MS) Disability Prevalence Cohort and compare them to those incurred by the general population. METHODS: Billed charges for 155 people with clinically definite or laboratory-supported MS were compared with those of age- and gender-matched non-MS controls. Billing data, including all inpatient and outpatient acute and rehabilitative medical care charges over a 5-year period surrounding a December 1, 1991 prevalence date, were analyzed. Data were correlated with level of disability using the Minimal Record of Disability for MS. RESULTS: Median total annual billed charges for most individuals with MS, including those with less severe ($1,277) and relapsing-remitting illness ($1,348), did not differ from those for controls ($1,327, p=0.075). Only those with severe MS (22.6%) had median annual medical charges higher than controls ($5,440, p < 0.001). Male patients with MS had higher median annual total charges ($2,353) than male controls ($762, p=0.003). Total charges for female patients with MS ($1,440) were not different from those for female controls ($1469). Median annual outpatient charges were 15% more for the MS group ($1,418) than for controls ($1,231). Patients with MS had a mean of 0.2 hospital admissions annually compared with 0.1 annual admissions per control patient. Among variables collected on persons with MS, the Expanded Disability Status Scale was the strongest predictor of level of charges (p < 0.001). CONCLUSION: Acute ambulatory- and hospital-billed charges for most patients with MS do not differ from those of the general population.     

Amino-terminal charge affects the periplasmic accumulation of recombinant heregulin/EGF hybrids exported using the Escherichia coli alkaline phosphatase signal sequence

An Escherichia coli expression system that exploits the bacterial alkaline phosphatase (PhoA) signal sequence to translocate recombinant human epidermal growth factor (hEGF) to the periplasm was used to evaluate how changes in the composition and sequence of amino acids near the PhoA-hEGF junction influence the periplasmic accumulation of recombinant protein. A series of chimeric structural genes was generated by in vitro replacement of hEGF sequence with analogous segments from the EGF-like domain of human heregulin (HRG), significantly altering the electrostatic character of the amino-terminal region of the mature protein. Quantitation of HRG/EGF protein in E. coli periplasmic extracts, by RP-HPLC, showed a fourfold decrease after one of two acidic residues located in the amino-terminal region of the mature hEGF, near the PhoA junction, was replaced. An additional threefold decrease was observed when the second acidic residue was replaced with a positively charged lysine. Further extension of the amino-terminal HRG sequence, beyond the first six residues, resulted in net neutralization of a more distant EGF acidic residue with no additional effect on protein yield. The importance of having a negatively charged group in the amino-terminal region of the mature protein was confirmed when insertion of an aspartic acid near the amino-terminus of two poorly expressed hybrid protein sequences resulted in a five- to eightfold increase in their recovery from the periplasm. This study demonstrates the importance of having negatively charged residues near the fusion junction of recombinant proteins expressed in E. coli using the PhoA signal sequence for protein export.     

Traffic modeling and state feedback control for metro lines

A complete traffic analysis for sequential metro lines with or without reference to a nominal time schedule is developed. The intrinsic instability of metro lines is pointed out. It is shown how well-chosen state-space formulations allow design of state-feedback control algorithms ensuring the stability of the system. The proposed traffic control algorithms have simple forms and are easy to implement in real-life systems. Simulations show the robustness of the proposed traffic control algorithms against disturbances occurring randomly on a loop line and their efficiency when compared to a classical time margin strategy     

Validation ďun modèle analytique de la pose par poussage des câbles à fibres optiques

The construction of an entire optical access networks for connected customers requires the mastery of optical fibre cable installation. We are interested in the pushing process in urban areas and the understanding of the global behaviour during this process and the estimation of the pushing force before laying are important. The work of Griffioen [5] and Buler [4] were used to develop software (taking into account friction and cable rigidity), including some improvements coming from a collaboration between France Télécom R&D Lannion and the LM2S. To go further in this process, in the first part of our work, we will work without buckling phenomena, that will be included in our modelisation in the second part of this paper. In order to validate our modelisation, comparison will be made between finite element simulations and experimental results obtained on a life-sized bench at France Télécom R&D Lannion.