Doppler broadening thermometry of acetylene and accurate measurement of the Boltzmann constant

In this paper, we present accurate measurements of the fundamental Boltzmann constant based on a line-shape analysis of acetylene spectra in the ν1 + ν3 band recorded using a tunable diode laser. Experimental spectra recorded at low pressures (0.25 - 9 Torr), have been analyzed using a Speed Dependent Voigt model that takes into account the molecular speed dependence effects. This line-shape model reproduces the experimental data with good accuracy and allows us to determine precise line-shape parameters for the P(25) transition of the ν1 + ν3 band. From the recorded spectra we obtained the Doppler-width and then determined the Boltzmann constant, k(B).

Diagnostic accuracy of the original 30-item and shortened versions of the Geriatric Depression Scale in nursing home patients

OBJECTIVE

To determine the diagnostic accuracy of the 30-item and shortened versions of the Geriatric Depression Scale (GDS) in diagnosing depression in older nursing home patients.

METHOD

Three hundred and thirty-three older nursing home patients participated in a prospective cross-sectional study in the Netherlands. Sensitivity and specificity, positive and negative predictive values, and the area under the receiver operating curve (ROC) were assessed. Cronbach alphas were also calculated. Both major depression (MDD) and minor depression (MinD) according to the DSM-IV criteria, measured with the Schedules of Clinical Assessment in Neuropsychiatry (SCAN), were used as 'gold standard'.

RESULTS

The cut-off point > or = 11 on the GDS-30 gave a sensitivity of 96.3% for MDD and 85.1% for MinD, with a specificity of 69.1%. The sensitivity of most of the shortened versions was sufficient, varying between 88.9% and 100% for MDD, and between 63.8% and 97.9% for MinD. With regard to the shortened versions, best sensitivity (96.3% and 78.7%) and specificity (69.5%) were found for the GDS-10 developed by D'Ath et al. (1994). The specificity rates for most of the shortened versions were found to be less satisfactory, varying between 18.9% and 74.1%. Sufficient internal consistency was found for the GDS-30, the GDS-15, the GDS-12 and the GDS-10, with Cronbach's alphas varying between 0.88 and 0.72.

CONCLUSIONS

The GDS-30 was found to be a valid and reliable case-finding tool for both major and minor depression in nursing home patients with no cognitive impairment and in patients with mild to moderate cognitively impairment (MMSE > or = 15). The GDS-10 (D'Ath et al., 1994) appeared to be the best least time-consuming alternative for the nursing home setting.

Discipline, subjectivity and personality: an analysis of the manuals of four psychological tests

The administration of psychological tests is highly regulated. Test manuals prescribe the instructions to the test subject, the time the test should take, where it should take place, whether and how the test administrator should answer questions from the test subject, and other aspects of the testing situation. Through the manual, the behaviour of test administrator and test subject is disciplined so that the subject may become measurable. The manuals of four tests are analysed, and the disciplinary mechanisms that operate in the administration of these tests are described. Attention is then given to the question whether the discipline of the test is repressive or productive. It is concluded that test manuals, while being central to the production of a psychological subject, also articulate an excess subjectivity in the measures they prescribe to exclude it from the testing situation.

Prediction of the in vivo biological activity of human recombinant follicle stimulating hormone using quantitative isoelectric focusing

Currently, the in vivo biopotency of commercial preparations containing the glycoprotein follicle-stimulating hormone (FSH) is declared on the basis of the ovarian weight augmentation assay as described in the British, European and United States Pharmacopoeias. Human FSH contains approximately 35% (W/W) carbohydrate which introduces considerable microheterogeneity (isohormones). Analysis of isohormones of recombinant FSH has revealed a relation between the isoelectric point (pl) and the in vivo bioactivity. Isohormones in the range of pl 3.5 are 100- to 200-fold more potent in the in vivo bioassay than isohormones with a pl of 5.5-6.0. These data suggest that quantification of the isohormone profile should enable us to predict the in vivo bioactivity. Thus, isohormones of recFSH samples were separated by isoelectric focusing (IEF), visualized by Coomassie brilliant blue G250 staining and quantified using densitometry. The data from 21 samples were compared with the in vivo bioassay data using partial least square (PLS) regression. A close correlation was found using a model with 2 PLS factors (correlation coefficient (r)=0.95, standard error of estimation SD 1. 02 lU/microg protein). In addition, ordinary least square (OLS) regression revealed a similar correlation between the fraction of isohormones between pl 3.9 and 4.9 and the in vivo bioactivity: r=0. 95, sd=1.4 lU/microg protein. Thus, an increase in the acidic isohormone fraction results in an increase in the in vivo bioactivity. The reverse is true for the amount of isohormones focusing between pl 5.1 and 5.7. An increase of this fraction results in a decrease of the in vivo bioactivity. These data are consistent with what might be expected from the in vivo bioassay data of the isohormones. The OLS model was subsequently validated using the guidelines of the European Centre for Validation of Alternative Methods (ECVAM) using 10 samples of recFSH that had not been used for the calibration. The relative standard deviation (RSD) of the mean difference between experimental and predicted in vivo bioactivity was approximately 6%. A Student's t-test performed on the experimental and predicted bioactivity data indicated that the predicted bioactivities do not deviate significantly from the experimental in vivo bioactivity data (P<0.05). These results demonstrate that the IEF scanning data can be used to predict the in vivo bioactivity with reasonable accuracy. This may be the first step towards replacing the in vivo bioassay for highly purified FSH by a physicochemical alternative. In general, quantitative charge-based separation methods like chromatofocusing, high performance capillary electrophoresis and ion exchange chromatography may also be considered as alternatives. Finally, quantitative charge profiling may prove to be as important for the estimation of the potency of other therapeutic glycoproteins like luteinizing hormone (LH), chorionic gonadotropin (CG), thyroid-stimulating hormone (TSH) and erythropoietin (EPO).