On testing factorial invariance: A reply to J.C.F. de Winter

Since its publication, the Driver Behavior Questionnaire (DBQ) has been used for comparing subgroups of respondents on the constructs formed through factor analyzing the questionnaire items. However, not enough attention has been paid to ascertaining that the instrument actually measures the same constructs in the same way in all respondent groups. I recently published an article (Mattsson, 2012) that aimed to do this for the Finnish 28-item version of the DBQ using the stage-wise factorial invariance approach in the Exploratory Structural Equation Modeling (ESEM) context. de Winter (2013) commented on the publication, arguing that the results were artifacts due to measurement error that too many factors were extracted and that too strict criteria for invariance were applied. In this contribution, I reply to each criticism and suggest methodological approaches for ensuring the measurement invariance of self-report instruments such as the DBQ.     

Enhanced electrochemical performance in lithium ion batteries of a hollow spherical lithium-rich cathode material synthesized by a molten salt method

A high voltage layered Li1.2Ni0.16Co0.08Mn0.56O2 cathode material with a hollow spherical structure has been synthesized by molten-salt method in a NaCI flux. Characterization by X-ray diffraction and scanning electron microscopy confirmed its structure and proved that the as-prepared powder is constituted of small, homogenously sized hollow spheres （1-1.5 μm）. The material exhibited enhanced rate capability and high first cycle efficiency due to the good dispersion of secondary particles. Galvanostatic cycling at different temperatures （20, 40, and 60 ℃） and a current rate of 2 C （500 mA.g-1） showed no significant capacity fade.     

Breast cancer screening with tomosynthesis--initial experiences

Experiences gained so far using tomosynthesis for breast cancer screening will be reported. A short summary of results from preparatory studies will also be presented. The sensitivity and specificity of breast tomosynthesis (BT) will be compared with conventional two-dimensional digital mammography (DM) for breast cancer screening in a population-based study. Over 2000 women have been examined so far with BT and DM. The BT reading is significantly more time-consuming than the DM reading. Preparatory studies have shown that BT has a higher diagnostic precision and higher accuracy of size measurements and stage determination than DM. There is potential to use lower compression force with BT compared with DM, without decreasing the diagnostic accuracy. BT might play an important role in clinical as well as screening mammography. A large-scale population-based study to investigate BT as a screening modality is underway.     

Comparing mixing and displacement ventilation in classrooms: pupils' perception and health

Several studies have found that indoor air quality (IAQ) in schools is often poor and may affect the health of the pupils. Building ventilation is a means to reduce pollutants indoors, but different designs should be evaluated for their effectiveness in different environments. In a field experiment performed at four classrooms in one school building, air was supplied either in the mixing or in the displacement mode, and we collected information on exposures, pupils' perception of IAQ and climate, and health symptoms and performed clinical examinations. The room temperature, relative humidity, concentration of CO?, and cat allergen were measured at the breathing height and were similar during each ventilation mode. The children perceived IAQ were similar in the two ventilation regimes, and there were few differences in symptom reports or clinical parameters. However, the pupils reported more eye symptoms during displacement ventilation. PRACTICAL IMPLICATIONS: Both mixing and displacement ventilation may be appropriate in school classrooms as long as the overall design, ventilation rates, and maintenance of systems are satisfactory.     

Doctors'' attitudes to fibromyalgia: a phenomenological study

BACKGROUND: Primary systemic amyloidosis is an uncommon disorder associated with the desposition of fragments of immunoglobulin light chains in a variety of tissues. Some patients present with peripheral neuropathy. The prognosis of these patients is not clear. METHODS: We searched the medical records of all patients seen at the Mayo Clinic between January 1, 1978 and December 31, 1994 with the diagnosis of amyloidosis. Twenty-six patients with sural nerve biopsy-proven amyloid neuropathy and a documented monoclonal protein in the serum or urine were studied. RESULTS: The most common symptoms that led to the diagnosis of primary amyloid neuropathy were paresthesias (81%), muscle weakness (65%), and numbness (58%). The median duration of symptoms before diagnosis was 29 months. Symptoms of autonomic neuropathy were present at diagnosis in 17 patients (65%). Other organs were involved in most patients. The monoclonal light chain protein detected was lambda in 18 patients (69%) and kappa in 8 (31%). The neuropathy was chronic, debilitating, and showed relentless progression. Twenty-two patients (85%) died (median survival 25 months) and 4 patients were alive at a median follow-up of 4.5 years. Progressive amyloidosis was the cause of death in most patients. Survival was significantly better in the patients with a serum albumin level >3 g/dL (median survival 31 months compared with 18 months; P <0.01, log-rank test). CONCLUSIONS: Patients with primary systemic amyloidosis in whom neuropathy is the dominant clinical manifestation often do not receive a diagnosis until years after the onset of symptoms. The prognosis is worse than previously indicated. Neuropathy does not improve with therapy.     

125I-labelling of an internally 75Se-labelled monoclonal antibody--biodistribution in tumour-bearing nude mice

A monoclonal antibody, C215, was first internally labelled with 75Se-methionine and then labelled with 125I. The biodistribution of the dual-labelled [125I][75Se]C215 was studied in tumour-bearing nude mice killed 3 days after injection. The biodistribution of the dual-labelled [125I][75Se]C215 was compared with the biodistribution of single-labelled [131I]C215 and [75Se]C215. Iodine-labelled antibodies seem to be damaged during iodination, affecting the disappearance rate and tumour uptake. There were no signs of dehalogenation of circulating antibodies or antibodies taken up in the tumour.     

Application of the fracture mechanics safety analysis to structural steel sections

This contribution presents a fracture mechanics safety analysis with finite element models applied on I-beams with defects in the tension flange. The moment rotation at room temperature was observed in the light of the toughness behaviour in front of initial notches. The results show very early crack initiation due to very large initial defects. The experiments were accompanied by a fracture mechanics safety analysis employing FEM. However, in temperature ranges of buildings plastically designed beams are subjected to sufficient rotation capacity, i.e. rotational ductility could be found.     

Risk factors for chronic graft-versus-host disease after bone marrow transplantation: a retrospective single centre analysis

We retrospectively compared the changes in serum albumin concentration and colloid osmotic pressure between survivors and nonsurvivors of prolonged (> or = 7 days) critical illness over a 2-year period from 1 July 1995. All patients had serum albumin measured daily, and colloid osmotic pressure measured 5 days a week, throughout their ICU admission. They received crystalloid and colloid infusions as well as parenteral or enteral feeding. Infusions of albumin were not used to treat hypoalbuminaemia. One hundred and forty-five patients were included, 66 nonsurvivors and 79 survivors. Nonsurvivors were significantly older than survivors [mean (95% CI): 58 (3.8) and 49 (4.1) years, respectively] and had a greater risk of death [mean (95% CI): 0.44 (0.06) and 0.28 (0.05); p < 0.05]. There was no significant difference in gender, APACHE II score [mean (95% CI): 22 (2.7) (nonsurvivors); 18 (2.3) (survivors)] or length of stay [median (interquartile range): 14 (9-27) days (nonsurvivors); 15 (9-26) days (survivors)]. There was no difference between the two groups in the absolute minimum serum albumin concentrations reached, the time to reach that minimum or the minimum in the first 7 days. However, nonsurvivors had a significantly lower mean serum albumin concentration: [mean (95% CI): 15.7 (5.1) g.l-1 compared with 18.3 (4.6) g.l-1 in survivors; p < 0.05]. They also had a lower recovery mean (the weighted mean after the minimum value): [mean (95% CI): 13.3 (5.1) g.l-1 (nonsurvivors) and 18.6 (5.3) g.l-1 (survivors); p < 0.01]. Analysis of colloid osmotic pressure results showed no difference between the groups in mean, minimum or recovery mean. Regression analysis of mean colloid osmotic pressure and albumin revealed that albumin only contributed 17% of the colloid osmotic pressure in these patients. The similar decrease in albumin in nonsurvivors and survivors may reflect the acute inflammatory response and/or haemodilution. However, survivors showed an ability to increase serum albumin concentrations, possibly owing to resumption of synthesis. The colloid osmotic pressure varied little between or within either group of patients, possibly because of the use of artificial colloids. There was no relationship between death and colloid osmotic pressure.