In-hospital malnutrition: indications of postoperative evolution

BACKGROUND: The question of the minimum number of Papanicolaou (Pap) smear slides that must be rescreened to draw statistically valid conclusions regarding the accuracy of screening often is raised. No method for generating answers in varying laboratory circumstances has achieved widespread application; standard statistical sample size calculations may represent such a resource. METHODS: A series of tables was constructed to display minimum required numbers of rescreens, with each table representing differing hypothetical laboratory circumstances. To use each table, assumptions must be specified in advance as to prevalence of abnormality, definition of error, baseline false-negative proportions (FNPs) of performance, and a degree of increase in FNPs that is considered a departure from baseline warranting concern, among others. RESULTS: The authors constructed four sample tables displaying minimum numbers of slides that must be rescreened in differing specified laboratory scenarios. Depending on assumed conditions and predetermined levels of satisfactory and unsatisfactory accuracy, the range of numbers is very broad (38-10,000). One example representing likely conditions indicates that 1040 slides must be reexamined; in another scenario, a sample size of 300 is sufficient. CONCLUSIONS: The minimum number of rescreened slides needed to draw statistically valid conclusions regarding Pap smear screening accuracy can be calculated using standard statistical methods. However, a number of assumptions must be detailed in advance. The authors offer this as a practical guide and a continuation of a general inquiry regarding Pap smear error rate measurement and display. The use of these tables raises at least as many questions as it answers, but still may represent a significant advance. Future efforts at further numeric characterization of aspects of Pap smear screening performance are warranted to enable rational decision making when performance is examined in the course of quality assurance, and during quality control and regulatory activities. [See editorial on pages 127-9, this issue.]     

Further developments in transient and pseudo-transient analysis of Mindlin plates

Some recent developments are presented on a unified approach to the static and transient dynamic geometrically nonlinear analysis of Mindlin plates with initial imperfections.     

Encapsulation of the Dinuclear Trithiolato-Bridged Arene Ruthenium Complex Diruthenium-1 in an Apoferritin Nanocage: Structure and Cytotoxicity

The effects of encapsulating the cytotoxic dinuclear trithiolato-bridged arene ruthenium complex [(η⁶-p-MeC₆H₄iPr)₂Ru₂(μ₂-S-p-C₆H₄tBu)₃]Cl (DiRu-1) within the apoferritin (AFt) nanocage were investigated. The DiRu-1-AFt nanocarrier was characterized by UV/Vis spectroscopy, ICP-MS, CD and X-ray crystallography. In contrast to previously reported Au- and Pt-based drug-loaded AFt carriers, we found no evidence of direct interactions between DiRu-1 and AFt. DiRu-1-AFt is cytotoxic toward immortalized murine BALB/c-3T3 fibroblasts transformed with SV40 virus (SVT2) and human epidermoid carcinoma A431 malignant cells, and exhibits moderate selectivity for these cancer cells over normal BALB/c-3T3 cells. DiRu-1-AFt triggers the production of reactive oxygen species, depolarization of mitochondrial membrane potential, and induces cell death via p53-mediated apoptosis. Comparison between our data and previous results suggests that the presence of specific interactions between a metal-based drug and AFt within the protein cage is not essential for drug encapsulation.     

The blood cells and haemopoiesis of Diplodus sargus L.: haematological values, cytochemistry and leukocytes'' response to vaccine stimulation

The human primary visual cortex consists of a region buried in the calcarine sulcus and a region outside this sulcus on the free surface of the occipital lobe. Since the depth of the calcarine sulcus can be easily estimated in magnetic resonance images of the living human brain, in vivo morphometry of the human primary visual cortex would be feasible for studying development, intersubject variability and interhemispheric asymmetry if the sulcal depth or a correlated measure such as the intracalcarine surface area would be a precise and reliable estimate of the total volume of the human primary visual cortex. The correlations between total volume of the striate cortex and its intra- and extra-calcarine surface areas were therefore tested in the present observations. The total volume of the striate cortex and the surface areas of its intra-and extracalcarine portions were measured in Nissl-stained serial sections through 20 adult human hemispheres. The intra- and extracalcarine portions of the striate area are not significantly correlated with each other, but correlated with the total volume of the striate cortex. The intracalcarine surface area or the depth of the calcarine sulcus are thus useful parameters for in vivo estimates of the total size of the striate cortex.     

Postbuckling behaviour of plates and shells using a mindlin shallow shell formulation

The paper presents a finite element Mindlin shallow shell formulation. Compared to a previous flat plate formulation it is shown that the addition of a shallow shell capability adds very little extra computational effort. Results are given for the postbuckling behaviour of square and circular plates subject to direct inplane loading and a square plate subject to inplane shear loading. Examples are also presented of the analyses of a shallow truss and cylindrical and spherical shells, all exhibiting snap through behaviour. Agreement with existing solutions is generally good and where possible the results are presented numerically.     

The local structure of gadolinium vanado-tellurite glasses

In this work we report on a vibrational spectroscopic, X-ray diffraction, and density measurement study of the structural properties of the ternary xGd₂O₃(100 − x)[7TeO₂·3V₂O₅] systems for various x values up to 70 mol%. Structural changes, as recognized by analyzing band shapes of X-ray diffraction and IR spectra, revealed that Gd₂O₃ causes a higher extent of network polymerization as far as x ≤ 40 mol%, while for x between 40 and 50 mol% showed a drastic structural modification which lead to the apparition of the GdVO₄ crystalline phase.     

Crystallite formation effect on the physicochemical properties of SPEEK membranes for fuel cell application

Crystallite formation in membranes cast from sulfonated poly(etheretherketone) (SPEEK) dispersions in dimethylacetamide has been investigated by differential scanning calorimetry. The crystallites melt at 220 °C and the melting enthalpy (ΔH_m) is strongly influenced by environmental conditions of solvent evaporation. When solvent is evaporated in air, ΔH_m decreases with increasing the evaporation temperature so that no crystallites are formed above 45 °C. The study of crystallite formation at 30 °C, under controlled relative humidity (RH) and solvent evaporation rate, has shown that ΔH_m decreases i) with decreasing RH from 75% to 5%, at constant evaporation rate, and ii) with increasing evaporation rate, especially at low RH. The exchange of protons with sodium ions results in an increase of the crystallite melting temperature thus indicating the presence of sulfonic groups in the crystallites. In comparison with crystallite-free SPEEK membranes, the presence of crystallites turns out in enhanced membrane mechanical properties, reduced hydration in liquid water above 75 °C, strongly anisotropic swelling (occurring mainly in the through-plane direction) and better performance in H₂/air fuel cell at 70 °C.     

Novel Nafion–zirconium phosphate nanocomposite membranes with enhanced stability of proton conductivity at medium temperature and high relative humidity

In order to increase the stability of Nafion conductivity at temperatures higher than 100 °C, composite membranes made of recast Nafion filled with different percentages of zirconium phosphate (ZrP) were investigated. The membrane preparation was carried out by a simple synthetic procedure based on the use of solutions of ZrP precursors in dimethylformamide. The formation of insoluble -type ZrP nanoparticles within the Nafion matrix was proved by ³¹P-MAS NMR and X-ray diffractometry. The membranes were characterized by TEM microscopy, ion-exchange capacity determinations, static stress–strain mechanical tests and conductivity measurements as a function of filler loading, at controlled relative humidity (r.h.) and temperature. An increasing filler loading results in enhanced membrane stiffness and in lower conductivity compared with pure recast Nafion. At 90% r.h. and 100 °C, the conductivity decreases from ≈0.07 S cm⁻¹ for pure Nafion to ≈0.03 S cm⁻¹ for the composite membrane containing 25 wt.% ZrP. Systematic conductivity measurements as a function of r.h. and temperature were carried out to draw a stability map for the conductivity of pure recast Nafion and of a composite membrane filled with 10 wt.% ZrP. These maps provide for each r.h. value the maximum temperature at which the conductivity remains stable for at least 150 h. The effect of zirconium phosphate is to increase the stability of conductivity at high temperature, with a gain up to 20 °C. This stability enhancement has been ascribed to the higher stiffness of the composite membrane.