Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.     

In vitro evaluation of the efficacy of skin barrier creams and protective gloves on percutaneous absorption of industrial solvents

OBJECTIVES: The aim of the experiments was to evaluate the efficacy of skin barrier creams (SBCs) and protective gloves and its potential for reduction of percutaneous absorption of industrial solvents. METHODS: We assessed percutaneous absorption of ethylene glycol (EG), isopropyl alcohol (IA) and 1,2,4-trimethylbenzene (TMB), using static diffusion cells. These solvents were applied neat (EG, TMB) as well as in 10% and 50% aqueous solution (EG, IA) or in 10% and 50% ethanol-diluted solution (TMB). Furthermore, we tested the percutaneous absorption of IA mixed in one cleaning agent (CA), used in newspaper printing shops to clean the rollers of printing machines. Additionally, the penetration behaviour of 10% and 50% solutions of EG, IA and TMB was tested. The experiments were carried out on untreated and on SBC-treated excised human skin from one donor, and on protective gloves. Saline was used as receptor fluid for EG and IA, and neat ethanol for TMB. RESULTS: The penetration of 50% EG, IA and TMB solutions through SBC-treated skin was higher than in untreated skin (factor 3.9 for EG, 0.32 for IA and 0.06 for TMB). The penetration of IA in the IA-CA mixture was five-times higher through untreated skin as for the single compound in 10% aqueous solution. In skin, treated with SBC, we found a 17-fold penetration enhancement of IA in the IA-CA mixture. No appreciable penetration of EG and IA was observed through nitrile rubber gloves. CONCLUSIONS: Our in vitro experiments could not demonstrate an efficacy of SBC to protect skin penetration for the tested solvents. The percutaneous absorption of all solvents in 50% solution was increased through skin treated with SBCs. Furthermore, SBCs enhance the penetration rates of solvents from complex mixtures compared with the single solvents. The tested gloves showed sufficient protection for the hydrophilic solvents, but not for TMB.     

Commentary on "Penetration of benzene, toluene and xylenes contained in gasolines through human abdominal skin in vitro".

In this commentary we refer to the new data recently published by Adami et al. [Adami, G., Larese, F., Venier, M., Barbieri, P., Lo Coco, F., Reisenhofer, E., 2006. Penetration of benzene, toluene and xylenes contained in gasolines through human abdominal skin in vitro. Toxicol. In Vitro 20, 1321-1330], which we acknowledge as a reliable basis for the retrospective assessment of percutaneous benzene absorption at the workplace. The data from Adami et al. (2006) are supported by the literature and by a German approach for calculating the contribution of the dermal uptake of benzene to the total body burden. This knowledge is important for the judgment of leukaemia suspected to be an occupational disease.     

Fat-free mass at admission predicts 28-day mortality in intensive care unit patients: the international prospective observational study Phase Angle Project

Purpose

Phase angle as measured by bioelectrical impedance analysis reflects fat-free mass. Fat-free mass loss relates to worse prognosis in chronic diseases. Primary aim of this study was: to determine the association between fat-free mass at intensive care unit admission and 28-day mortality.

Methods

Ten centres in nine countries participated in this multicentre prospective observational study. The inclusion criteria were age >18 years; expected length of stay >48 h; absence of pacemaker, heart defibrillator implant, pregnancy and lactation. Fat-free mass was assessed by measurement of the 50-kHz phase angle at admission. The primary endpoint was 28-day mortality. The area under the receiver operating characteristic curve (AUC) was used to assess prediction of 28-day mortality by fat-free mass at ICU admission. The variables associated with 28-day mortality were analysed by means of multivariable logistic regression.

Results

Of the 3605 patients screened, 931 were analysed: age 61 ± 16 years, male 60 %, APACHE II 19 ± 9, body mass index 26 ± 6, day 1 phase angle 4.5° ± 1.9°. Day 1 phase angle was lower in patients who eventually died than in survivors (4.1° ± 2.0° vs. 4.6° ± 1.8°, P = 0.001). The day 1 phase angle AUC for 28-day mortality was 0.63 [0.58–0.67]. In multivariable analysis, the following were independently associated with 28-day mortality: age (adjusted odds ratio (aOR) 1.014 [95 % confidence interval 1.002–1.027], P = 0.03), day 1 phase angle (aOR 0.86 [0.78–0.96], P = 0.008), APACHE II (aOR 1.08 [1.06–1.11], P < 0.001), surgical patient (aOR 0.51 [0.33–0.79], P = 0.002), and admission for other diagnosis (aOR 0.39 [0.21–0.72], P = 0.003). A multivariable combined score improved the predictability of 28-day mortality: AUC = 0.79 [0.75–0.82].

Conclusion

Low fat-free mass at ICU admission is associated with 28-day mortality. A combined score improves mortality predictability. Trial registration: NCT01907347 (http://www.clinicaltrials.gov).

     

The impact of systemic sclerosis on arterial wall stiffness parameters and endothelial function

Systemic sclerosis (SSc) is characterized by thickening and fibrosis of skin and internal organs that is associated with vascular damage. SSc may lead to arterial dysfunction and premature aging of the arteries. However, its relationship with parameters of arterial wall dysfunction has not been fully explored. To determine if carotid–radial pulse wave velocity (PWV), aortic augmentation index (AIx) and endothelial function are altered in SSc patients, 17 consecutive patients with SSc and 34 age- and gender-matched controls were included in our study. PWV and AIx were assessed non-invasively by applanation tonometry. The endothelium-dependent flow-mediated dilatation (FMD) test in a brachial artery was performed by the ultrasound system. The blood investigations included serum lipid profile, glucose, and high-sensitivity CRP (hsCRP) measurements. As compared to controls, SSc patients had significantly higher medians of the AIx (p = 0.002) and the PWV (p = 0.04) and the median of the FMD was significantly lower (p = 0.001). Stepwise linear regression including comorbid factors showed that SSc was a significant independent predictor of all arterial wall parameters measures. SSc patients have increased AIx and PWV and lower FMD as compared to control subjects. The relationship between SSc and measures of arterial wall parameters still remains unclear. Though replication of the results presented here is required, we conclude that SSc has a great impact on large and conduit arteries damage.     

Effects of verapamil on indirect muscle twitch responses

The effects on indirectly elicited muscle twitch amplitude associated with the calcium (slow) channel blocker, verapamil, with or without pancuronium were investigated using isolated bullfrog sciatic nerve-sartorius muscle preparations. Verapamil (2-8 mM) produced a dose-related depression of indirect muscle twitch height (P less than 0.05). Twitch response was depressed 11% below control by the lowest concentration employed and 86% by the highest concentration. Pancuronium (0.07 mM) depressed neuromuscular function 35% below control (P less than 0.05). The combination of 5 mM or 8 mM verapamil with 0.07 mM pancuronium caused significantly greater degrees of depression than either drug alone. Verapamil produced significant depression of twitch height in vitro in relatively high concentrations. The mechanism of action remains unknown. Verapamil possesses pharmacologic properties that may be unrelated to slow (calcium) channel inhibition. The reduction of muscle twitch height caused by verapamil alone (5 mM) could not be antagonized by neostigmine, calcium, or frequent washings.     

The use of information technologies for diagnosis in ophthalmology

In 2003, a health IT programme for clinical decision support started in Lithuania. An initial goal was to create databases for ophthalmology images and to develop processing algorithms to extract diagnostically valuable information from images. We have investigated how vectors, consisting of the parameters derived from fundus images, are distributed and whether they form specific groups. When analysing the multidimensional patient data vectors, comprising all the 27 image parameters, it was impossible to separate the healthy eyes from the diseased ones. However, it was possible to simplify the system by eliminating redundant parameters and introducing new ones that represent a subset of parameters from the initial group. Thus it may prove possible to identify glaucoma using this system of parameters.     

Percutaneous absorption and metabolism of 2-butoxyethanol in human volunteers: a microdialysis study

We determined percutaneous absorption kinetics of 2-butoxyethanol (BE) in volunteers using microdialysis. Four male volunteers were dermally exposed twice to 90% and 50% aqueous solutions (v/v) of BE for 4.5h. To determine percutaneous absorption kinetics the concentration of BE was measured in the dialysate samples collected at 30 min-intervals throughout exposure. The systemic absorption, which is needed to determine recovery of the BE in the dialysate, was estimated from the concentration of the main metabolite of BE, free butoxyacetic acid (BAA) in urine. A pseudo steady-state percutaneous absorption was reached approximately at 2h of exposure for both BE concentrations. The maximum dermal flux of 50% BE was higher than that of 90% BE (2.8+/-0.4, 1.9+/-0.6 mg cm(-2)h(-1), respectively). The more diluted BE solution showed shorter lag time: 25 min versus 39 min. The amount of BAA was determined in the pooled dialysate samples collected at 4 and 4.5h. The dermal metabolism seems to be low, the BAA amount ranged from 0.03% to 1.9% of the BE in the same dialysate. Our study demonstrates applicability of microdialysis technique for assessment of percutaneous absorption kinetics and dermal metabolism without interference from the systemic compartment.