Development of a Food-Based Diet Quality Scale for Brazilian Schoolchildren Using Item Response Theory.

Item response theory (IRT) is a psychometric method that provides probabilistic model-based measurements. Its use is relatively recent in the assessment of food consumption, especially through dietary assessment tools. This study aims (1) to develop a food-based diet quality scale for Brazilian schoolchildren using IRT, and (2) to apply the scale to a representative sample of schoolchildren from a Southern Brazilian city. The scale was developed with daily consumption frequency of foods from 835 students who completed the Food Intake and Physical Activity of Schoolchildren questionnaire. Questionnaire foods were grouped into 10 items according to their nutritional similarities and were evaluated by full-information factor analysis that indicated a dominant factor explaining 28% of the variance. Psychometric item analysis was performed using Samejima's model. The scale covered all levels of diet quality, from "very poor" (scores < 95) to "very good" (scores ≥ 130). Children who had higher diet quality scores consumed beans, meat, fish, eggs, fruits, vegetables, dairy products, and water more frequently, while reducing the consumption of ultraprocessed sugary foods, ultraprocessed savoury snacks and sausages, and sugary drinks. Of 6323 children, an average of less than 10% consumed the highest diet quality scores (good or very good diet quality) and about 60% of children consumed low diet quality scores. The scale can be applied to other schoolchildren with the same measure precision.

Increasing 'ease of sliding' also increases friction: when is a lubricant effective?

We investigate experimentally the effective Coulomb friction exerted by a granular medium on a shearing plate, varying the medium depth. The plate is driven by a spring connected to a motor turning at a constant speed and, depending on the system configuration, performs continuous sliding or stick and slip in different proportions. We introduce an order parameter which discriminates between the different regimes expressing the fraction of time spent in slipping. At low driving speed, starting from zero layers of interstitial granular material, the average friction coefficient decreases when a few layers are added, while the order parameter stays close to zero. By further increasing the granular depth, the friction undergoes a sudden increase but the order parameter does not change notably. At an intermediate driving speed, however, both the friction and the order parameter undergo a sudden increase, which for the order parameter amounts to several orders of magnitude, indicating that the plate is more braked but nevertheless keeps sliding more easily. For medium-high driving speeds, full sliding is obtained for only one layer of interstitial matter, where friction has a minimum, and is maintained for all increasing depths while friction increases. These observations show that the ease of slipping is not determined by friction alone, rather by the highly complex interplay between driving velocity, friction, and the depth of the medium.

Maintenance with rituximab is safe and not associated with severe or uncommon infections in patients with follicular lymphoma: results from the phase IIIb MAXIMA study.

Previous randomized trials have demonstrated that rituximab maintenance (R-maintenance) can prolong time to progressive disease in patients with follicular lymphoma (FL). The phase IIIb MAXIMA study (NCT00430352) was a large prospective evaluation of R-maintenance in a daily care setting. The primary objective was safety. Secondary objectives included progression-free survival, overall survival, time to next lymphoma treatment, and partial response (PR) to complete response/unconfirmed (CR/CRu) conversion rate. Patients (n = 545) with first-line or relapsed FL who responded to 8 cycles of rituximab-based induction received R-maintenance every 2 months for 2 years. At study entry, 380 patients had CR or CRu, and 165 had PR. The median age was 57.0 years. The most common non-hematologic adverse events (AEs, excluding infusion-related reactions) were cough (9.9 % of patients), fatigue (7.5 %), nasopharyngitis (7.1 %), back pain (6.5 %), diarrhea (6.9 %), arthralgia (6.0 %), headache and hypertension (5.2 % each), and pyrexia (5.1 %). The majority of AEs were grade 1 or 2. Grade 3, 4, and 5 infections occurred in 21 (3.9 %), 2 (0.4 %), and 1 (0.2 %) patient, respectively. Fifty-one hematologic AEs occurred in 6.6 % (n = 35) of patients. Grade 3/4 prolonged neutropenia and hypogammaglobulinemia occurred in 13 (2.4 %) and 5 (0.9 %) patients, respectively. All cases of prolonged neutropenia or hypogammaglobulinemia were manageable and resolved. Fast infusion did not alter the safety profile. Efficacy was comparable with results from previous trials. R-maintenance is safe in a daily care setting for patients with first-line or relapsed FL.

Why can organic liquids move easily on smooth alkyl-terminated surfaces?

The dynamic dewettability of a smooth alkyl-terminated sol-gel hybrid film surface against 17 probe liquids (polar and nonpolar, with high and low surface tensions) was systematically investigated using contact angle (CA) hysteresis and substrate tilt angle (TA) measurements, in terms of their physicochemical properties such as surface tension, molecular weight/volume, dielectric constant, density, and viscosity. We found that the dynamic dewettability of the hybrid film markedly depended not on the surface tensions but on the dielectric constants of the probe liquids, displaying lower resistance to liquid drop movement with decreasing dielectric constant (ε < 30). Interfacial analysis using the sum-frequency generation (SFG) technique confirmed that the conformation of surface-tethered alkyl chains was markedly altered before and after contact with the different types of probe liquids. When probe liquids with low dielectric constants were in contact with our surface, CH3 groups were preferentially exposed at the solid/liquid interface, leading to a reduction in surface energy. Because of such local changes in surface energy at the three-phase contact line of the probe liquid, the contact line can move continuously from low-surface-energy (solid/liquid) areas to surrounding high-surface-energy (solid/air) areas without pinning. Consequently, the organic probe liquids with low dielectric constants can move easily and roll off when tilted only slightly, independent of the magnitude of CAs, without relying on conventional surface roughening and perfluorination.

Unusual dynamic dewetting behavior of smooth perfluorinated hybrid films: potential advantages over conventional textured and liquid-infused perfluorinated surfaces.

From a viewpoint of reducing the burden on the environment and human health, an alternative method for preparing liquid-repellent surfaces without relying on the long perfluorocarbons (C((X-1)/2)F(X), X ≥ 17) has been strongly demanded lately. In this study, we have successfully demonstrated that dynamic dewettability toward various probe liquids (polar and nonpolar liquids with high or low surface tension) can be tuned by not only controlling surface chemistries (surface energies) but also the physical (solid-like or liquid-like) nature of the surface. We prepared smooth and transparent organic-inorganic hybrid films exhibiting unusual dynamic dewetting behavior toward various probe liquids using a simple sol-gel reaction based on the co-hydrolysis and co-condensation of a mixture including a range of perfluoroalkylsilanes (FASX, C((X-1)/2)F(X)CH2CH2Si(OR)3, where X = 3, 9, 13, and 17) and tetramethoxysilane (Si(OCH3)4, TMOS). Dynamic contact angle (CA) and substrate tilt angle (TA) measurements confirmed that our FASX-hybrid films exhibited excellent dynamic dewetting properties and were mostly independent of the length of perfluoroalkyl (Rf) groups. For example, 10 µL droplets of ultralow surface tension liquids (e.g., diethyl ether (γ = 16.26 dyn/cm) and n-pentane (γ = 15.51 dyn/cm)) could move easily on our FAS9-, FAS13-, and FAS17-hybrid film surfaces at low substrate TAs (<4°) without pinning. This is comparable or superior to the best perfluorinated textured and flat surfaces reported so far. This exceptional dynamic dewetting behavior appeared only when TMOS molecules were added to the precursor solutions; we assume this is due to co-condensed TMOS-derived silica species working as spacers between the neighboring Rf chains, enabling them to rotate freely and in doing so provide a surface with liquid-like properties. This led to the distinguished dynamic dewettability of our hybrid films, regardless of the small static CAs. Our FASX-hybrid films also displayed excellent chemical and physical durability against thermal stress (~250 °C), high-temperature (150 °C) oil vapor, and various other media (perfluoro liquid, boiling water, and weak acid) without degrading their dynamic dewettability. Such exceptional durability has been rarely seen on conventional perfluorinated surfaces reported so far.

Smooth perfluorinated surfaces with different chemical and physical natures: their unusual dynamic dewetting behavior toward polar and nonpolar liquids.

The effects of surface chemistry and the mobility of surface-tethered functional groups of various perfluorinated surfaces on their dewetting behavior toward polar (water) and nonpolar (n-hexadecane, n-dodecane, and n-decane) liquids were investigated. In this study, three types of common smooth perfluorinated surfaces, that is, a perfluoroalkylsilane (heptadecafluoro-1,1,2,2-tetrahydrooctyl-dimethylchlorosilane, FAS17) monomeric layer, an amorphous fluoropolymer film (Teflon AF 1600), and a perfluorinated polyether (PFPE)-terminated polymer brush film (Optool DSX), were prepared and their static/dynamic dewetting characteristics were compared. Although the apparent static contact angles (CAs) of these surfaces with all probe liquids were almost identical to each other, the ease of movement of liquid drops critically depended on the physical (solidlike or liquidlike) natures of the substrate surface. CA hysteresis and substrate tilt angles (TAs) of all probe liquids on the Optool DSX surface were found to be much lower than those of Teflon AF1600 and FAS17 surfaces due to its physical polymer chain mobility at room temperature and the resulting liquidlike nature. Only 6.0° of substrate incline was required to initiate movement for a small drop (5 µL) of n-decane, which was comparable to the reported substrate TA value (5.3°) for a superoleophobic surface (θ(S) > 160°, textured perfluorinated surface). Such unusual dynamic dewetting behavior of the Optool DSX surface was also markedly enhanced due to the significant increase in the chain mobility of PFPE by moderate heating (70 °C) of the surface, with substrate TA reducing to 3.0°. CA hysteresis and substrate TAs rather than static CAs were therefore determined to be of greater consequence for the estimation of the actual dynamic dewetting behavior of alkane probe liquids on these smooth perfluorinated surfaces. Their dynamic dewettability toward alkane liquids is in the order of Optool DSX >> Teflon AF1600 ≈ FAS17.

A thermally stable, durable and temperature-dependent oleophobic surface of a polymethylsilsesquioxane film.

Polymethylsilsesquioxane (PMSQ) films prepared by a simple sol-gel reaction of methyltriethoxysilane were found to possess thermally stable, durable, and temperature-dependent oleophobic properties under high temperature (~350 °C) conditions.

Novel transparent zirconium-based hybrid material with multilayered nanostructures: studies of surface dewettability toward alkane liquids.

We have successfully prepared unique inorganic-organic hybrid materials that demonstrate excellent transparency and dewettability toward various alkane liquids (n-hexadecane, n-dodecane and n-decane) without relying on conventional surface roughening and perfluorination. Such coatings were made using a novel family of hybrid materials generated by substituting carboxylic acids, with a range of alkyl chain lengths (CH(3)(CH(2))(x-2)COOH where x = total carbon number, i.e., 10, 12, 14, 16, 18, 22, or 24, into zirconium (Zr) tetra-propoxide complexes. This precursor was then mixed with acetic acid and spincast to produce transparent thin Zr-carboxylic acid (ZrCA(x)) hybrid films using a nonhydrolytic sol-gel process. Fourier transform infrared spectroscopy provided proof of Zr-O-Zr network formation in the films upon casting and also followed changes to the physical nature (liquid-like or solid-like) of the alkyl chain assemblies depending upon alkyl chain length. X-ray diffractometry revealed that the hybrid films prepared using the longer chain carboxylic acids (ZrCA(x≥18)) spontaneously self-assembled into lamella structures with d-spacings ranging from 29.5 to 32.7 Angstroms, depending on the length of the alkyl chain. On the other hand the remaining films (ZrCA(x<18)) showed no such ordering. Moreover, the dynamic dewetting behavior of our hybrid films with alkane liquids was also strongly affected by alkyl chain length. ZrCA(x) films with x = 12, 14, and 16 showed the best dynamic oleophobicity among the seven hybrid films. In particular, small volume alkane droplets (5 µL) could be easily set in motion to move across and off ZrCA(14) film surfaces without pinning at low tilt angles (~6°).

How to reduce resistance to movement of alkane liquid drops across tilted surfaces without relying on surface roughening and perfluorination.

Alkylsilane-derived monolayer-covered surfaces generally display a reasonably good level of hydrophobicity but poor oleophobicity. Here, we demonstrate that the physical attributes of alkylsilane-derived surfaces (liquid-like or solid-like) are dependent on the alkyl chain length and density, and these factors subsequently have significant influence upon the dynamic dewetting behavior toward alkanes (C(n)H(2n+2), where n = 7-16). In this study, we prepared and characterized hybrid films through a simple sol-gel process based on the cohydrolysis and co-condensation of a mixture of a range of alkyltriethoxysilanes (C(n)H(2n+1)Si(OEt)(3), where n = 3, 6, 8, 10, 12, 14, 16, and 18) and tetramethoxysilane (TMOS). Surprisingly, when the carbon number (C(n)) of alkyl chain was 10 and below, the produced hybrid films were all smooth, highly transparent, and showed negligible contact angle (CA) hysteresis. On these hybrid surfaces, 5 µL drops of alkanes (n-hexadecane, n-dodecane, and n-decane) could move easily at low tilt angles (<5°) without pinning. On the other hand, when the C(n) exceeded 12, both transparency and mobility of probe liquids significantly worsened. In the former case, TMOS molecules played key roles in both forming continuous films (as a binder) and improving flexibility of alkyl chains (as a molecular spacer), resulting in the smooth liquid-like surfaces. Silylation of the hybrid film and subsequent dynamic CA measurements proved the presence of silanol groups on the outermost surfaces and demonstrated that the dynamic dewettability of hybrid films worsened as packing densities increased. Additionally, solvent effects (high affinity) between the alkyl chains and alkane liquids imparted a more liquid-like character to the surface. Thanks to these simple physical effects, the resistance to the alkane droplet motion across tilted surfaces was markedly reduced. With the longer carbon chains, the chain mobility was strictly inhibited by mutual interactions between neighboring alkyl chains even in the presence of TMOS molecules. The achieved surfaces displayed a solid-like nature along with surface defects, leading to inferior dynamic oleophobicity. Therefore, the critical C(n) of alkyl chain used for determining final dynamic dewetting behavior against alkane liquids was 12. Furthermore, our hybrid surfaces exhibited excellent antifingerprint properties, particularly demonstrating low adhesion and easy removal from the surface.

A physical approach to specifically improve the mobility of alkane liquid drops.

Seamless control of resistance to liquid drop movement for polar (water) and nonpolar alkane (n-hexadecane, n-dodecane, and n-decane) probe liquids on substrate surfaces was successfully demonstrated using molten linear poly(dimethylsiloxane) (PDMS) brush films with a range of different molecular weights (MWs). The ease of movement of liquid drops critically depended on polymer chain mobility as it relates to both polymer MW and solvent swelling on these chemically- and topographically identical surfaces. Our brush films therefore displayed lower resistances to liquid drop movement with decreasing polymer MW and surface tension of probe liquid as measured by contact angle (CA) hysteresis and tilt angle measurements. Subsequently, while mobility of water drops was inferior and became worse at higher MWs, n-decane drops were found to experience little resistance to movement on these polymer brush films. Calculating CA hysteresis as Δθ(cos) = cos θ(R) - cos θ(A) (θ(A) and θ(R) are the advancing and receding CAs, respectively) rather than the standard Δθ = θ(A) - θ(R) was found to be advantageous for estimation of the actual dynamic dewetting behavior of various probe liquids on an inclined substrate.

Highly loaded silicone nanocomposite exhibiting quick thermoresponsive optical behavior.

Bulk silicone nanocomposites with thermoresponsive optical behavior were fabricated using silica nanoparticle fillers within a cross-linked silicone matrix. Silica nanoparticles (25 nm diameter) were surface-modified, allowing for even distribution at 6-24 wt % within and covalent bonding to the silicone matrix. Utilizing the temperature-dependent match/mismatching of the refractive indices of the silica nanoparticle filler and the silicone matrix, bulk nanocomposites are highly transparent at room temperature and demonstrate significant increases in opacity with increasing temperature up to 100-150 °C. Such a response could be cycled quickly and repeatedly with no detrimental effect on the material.

Lamination of alumina membranes to polymer surfaces: thick, hard, transparent, crack-free alumina films on polymers with excellent adhesion.

Hard and transparent alumina (Al(2)O(3)) films with thicknesses in the range of 500 nm to 5 µm were successfully formed on polymethylmethacrylate (PMMA) and polystyrene (PS) surfaces. Our process is based on a lamination of anodized aluminum membranes (AAMs) to the polymer surfaces, followed by chemical etching. Because of capillary force, molten PS and liquid PMMA precursor were successfully pulled into the nanopores (10 nm diameter) within the Al(2)O(3) layers and solidified by cooling or polymerization, respectively. Our resulting AAM-laminated surfaces exhibited excellent adhesion and surface mechanical properties similar to those of fused silica, remaining crack-free and transparent even with Al(2)O(3) thicknesses exceeding 1 µm.

Brownian motor in a granular medium.

In this work we experimentally study the behavior of a freely rotating asymmetric probe immersed in a vibrated granular medium. For a wide variety of vibration conditions the probe exhibits a steady rotation whose direction is constant with respect to the asymmetry. By changing the vibration amplitude and by filtering the noise in different frequency bands we show that the velocity of rotation depends not only on the RMS acceleration Γ, but also on the amount of energy provided to two separate frequency bands, which are revealed to be important for the dynamics of the granular medium: The first band governs the transfer of energy from the grains to the probe, and the second affects the dynamics by altering the viscosity of the vibro-fluidized material.

Using the fact that wetting is contact line dependent.

Two series of experiments, both involving contact line pinning, are reported that were designed using the contact line perspective of wetting and require this perspective to explain the observed results. Perspectives based on contact areas, for example, Wenzel's and Cassie's, are not useful in either of these experimental situations. In the first type of experiment described, sessile water drops were pinned on low contact angle hysteresis surfaces using 40 different shape/size lithographed hydrophilic features. Hydrophilic arcs (sections of circles), short wedges (pointed to the center of the circle), long wedges (pointed to the opposite side of the circle), and the upper outlines of the short and long wedges were prepared and studied. These features were based on circles with diameters of 4 and 6 mm and arcs of 30°, 60°, 90°, and 120°. The volume of water that could be pinned depends on the linear shape of the portion of the feature that interacts with the receding contact line and not on the feature area. In the second type of experiment, thin hydrophilic contact lines were used to support films of water (puddles and kinetically trapped thin films) on water-repellent surfaces and used to control the shape (both 2D and 3D) of these thin films and puddles. Elongated water puddles, 60 mm long and 4 mm wide, were prepared using contact line patterns with line widths of 500, 250, and 100 µm. Curved puddles, geometric shapes, letters of the English alphabet, and puddles with variable liquid thicknesses (heights) were also prepared.

Hydrophobic/superhydrophobic oxidized metal surfaces showing negligible contact angle hysteresis.

Dynamic wettability of oxidized metal (aluminum and titanium) surfaces could be tuned by chemical vapor deposition (CVD) of 1,3,5,7-tetramethylcyclotetrasiloxane (D(4)(H)). This facile CVD method produces not only monomeric layers but also particulate films by changing the CVD temperature, resulting in a marked difference in the final wetting properties. In the samples prepared at 80°C for ~3 days, D(4)(H) layers with thicknesses of ~0.5 nm were formed on the surfaces without discernible change in surface morphology, as evidenced by X-ray photoelectron spectroscopy and atomic force microscopy. After this D(4)(H) monomeric layer formation, the hydrophilic oxidized aluminum and titanium surfaces became hydrophobic (advancing/receding water contact angles (θ(A)/θ(R))=102-104°/99-102°) showing essentially negligible contact angle hysteresis. Performing CVD of D(4)(H) at 180°C for ~1 day produced opaque film with particulate morphologies with diameters in the range of 500 nm to 4 µm observed on the surfaces. This geometric morphology enhanced the surface hydrophobicity (θ(A)/θ(R)=163°/160-161°). Droplets on these negligible-hysteresis surfaces moved very easily without "pinning".

A model for psychiatric questionnaires with embarrassing items.

We propose an item response theory model to analyse psychiatric questionnaires that contain embarrassing items. We use Bayesian methods to estimate its parameters and consider a simulation study to evaluate the performance of the proposed estimators. The results are illustrated with the analysis of data collected to evaluate teenager depression, highlighting the gender difference in the probabilities of 'crying crisis', a trait known to embarrass some male populations.

High-resolution soft lithography of thin film resists enabling nanoscopic pattern transfer.

Soft UV-imprint lithography at sub-micron dimensions was achieved in thin films of photopolymer resist. The imprinting was enabled by overcoming resist absorption by polydimethylsiloxane (PDMS) through surface treatment with a layer of (heptadecafluoro-1,1,2,2-tetrahydrodecyl)dimethylchlorosilane. Characterization of the composite molds was done by X-ray photoelectron spectroscopy, nanoindentation, and contact angle measurements. PDMS molds treated with fluoroalkylsilane layer were used to imprint into thin films (70-630 nm) of UV curable resins consisting of either polyurethanes or acrylates, replicating with high fidelity features over the surface of wafer substrates. The use of these highly conformal PDMS molds allowed the patterning of functional materials including gold and aluminium by a simple imprint lithographic technique. This is the first report of the use of modified PDMS surfaces in an imprint process that enables the transfer of sub-micron patterns to underlying layers for device structure fabrication. The patterned features were studied with atomic force microscopy, scanning electron microscopy, and optical microscopy.

Comparision of the BAX® System with an in-house MSRV method for the detection of Salmonella in chicken carcasses and pork meat

A study was performed to compare the analytical procedure of the BAX® System for Salmonella PCR assay with the Modified Semi-Solid Rappaport-Vassiliadis (MSRV) method, for the detection of Salmonella in naturally contaminated chicken carcass samples (n = 762) and raw pork meat (n = 566). The chicken carcasses samples were collected during slaughtering after defeathering or immediately after evisceration and the raw pork meat collected from the deboned head of recently slaughtered pigs and others deboned raw fresh pork meat. The BAX® System detected 134 Salmonella-positive samples in chicken carcasses and 145 samples in pork meat, while the MSRV method isolated 142 and 144 Salmonella-positive samples, respectively. No significant difference was observed between the two methods for chicken carcasses and pork meat, according to McNemar test at the 5 percent level.

Um estudo foi realizado com o objetivo de comparar o procedimento analítico de detecção de Salmonella com o Sistema BAX® automatizado, baseado na Reação em Cadeia da Polimerase (PCR) com o método de Rappaport-Vassiliadis em Agar Semi-Sólido modificado (MSRV) para detecção de Salmonella em amostras de carcaças de frango naturalmente contaminadas (n=762) e retalhos de carne suía (n=566). O Sistema BAX® detectou 134 amostras positivas para Salmonella em carcaças de frango e 145 amostras positivas para Salmonella em retalhos de carne suína, enquanto o MSRV detectou 142 e 144 amostras positivas respectivamente. Não houve diferença estatisticamente significativa entre os dois métodos, segundo McNemar ao nível de significância de 5 por cento.

Brownian forces in sheared granular matter.

We present results from a series of experiments on a granular medium sheared in a Couette geometry and show that their statistical properties can be computed in a quantitative way from the assumption that the resultant from the set of forces acting in the system performs a Brownian motion. The same assumption has been utilized, with success, to describe other phenomena, such as the Barkhausen effect in ferromagnets, and so the scheme suggests itself as a more general description of a wider class of driven instabilities.