Gender differences in adolescents’ out-of-school literacy practices: A multifaceted approach

The present study examined the out-of-school literacy activities of 70 students in 7th grade of prevocational training schools in the Netherlands. Guttmann’s Facet Theory was applied to study literacy as a complex, multifaceted phenomenon. With the increasing influence of digital technologies, the facet design approach was found especially suited to track the many changes occurring in presentation modalities, functions, and productive versus consumptive uses of literacy. The study shows that the facet approach was useful in pinpointing how these shifts in literacy engagement turn out differently for boys and girls. Based on self-reports via an Internet questionnaire, the study shows that girls outscored boys in every aspect of literacy, including computer and Internet based literacy practices. However, while among girls a more balanced profile was found regarding the engagement in traditional and new literacy practices, the boys reported a high preference for the new digital media. Moreover, we found that girls, compared to boys, used new literacy activities more often for educational purposes. The findings suggest that, given this more balanced profile, girls, compared to boys, are less at risk of losing touch with traditional print-based educational literacy in school.     

Evaluation of the electrochemical properties of 3-hydroxyflavone using voltammetric methods

Electrochemical behavior of ring C of 3-hydroxyflavone (3-HF) has been investigated by cyclic and differential pulse voltammetry, using a glassy carbon electrode (GCE) in different buffer systems. It exhibited a sensitive diffusion controlled anodic peak at 0.70 V (vs Ag/AgCl) in a buffer system at pH 2.0. At higher pH, 8.0, while the peak at 0.70 V shifted to 0.41 V, a new peak at 0.8 V appeared. Moreover, electrochemical method was applied to investigate the antioxidant effect and metal chelating properties of 3-HF with Cd²⁺, Cu²⁺, Hg²⁺ and Pb²⁺ as they could have possible toxicological effects, for which fluorescence technique were also applied. Antioxidant effect was determined in terms of trolox equivalent antioxidant capacity (TEAC) using the peak areas of cyclic voltammetry (CV), which indicated that 1.0 mM 3-HF is equivalent to 0.2 mM of trolox. Such a result might be another indication of the importance of hydroxyl groups on the other rings of flavones. Electrochemical and fluorescence spectroscopic methods revealed that the best interactions of the cations could be obtained depending on the pH of the medium. Selective interactions of Cd²⁺ and Cu²⁺ at pH 2 and 7, respectively, were observed.     

Effect of laser etching on the fracture strength of the monolithic zirconia and fiber-reinforced composite inlay-retained fixed partial dentures

Aim: The aim of this study was to evaluate the fracture strength of monolithic zirconia and fiber-reinforced composite (FRC) inlay-retained FPDs, both of which are cemented to the laser-etched cavity surfaces.

Materials and Methods: Eighty freshly extracted sound human teeth were used. A premolar and a molar tooth were embedded in an autopolymerizing acrylic resin. Forty acrylic resin models were randomly divided into two groups including monolithic zirconia and FRC inlay-retained FPDs (n = 20). Then, these groups were divided into two subgroups according to conditioning of the cavity surfaces with or without Er:YAG laser etching. Monolithic zirconia inlay-retained FPDs were produced by an inLab MC XL milling device using monolithic zirconia blocks. Tescera? Fiber Reinforcement Materials were used for the FRC inlay-retained FPDs. After 10.000 thermal cycles, fracture strength test was applied to the specimens.

Results: The monolithic zirconia inlay-retained FPDs exhibited the highest fracture strength than the FRC inlay-retained FPDs. Fracture strength was increased with laser etching for both restorative materials (p < 0.05).

Conclusion: Laser etching had positively effect on the fracture strength of the inlay-retained FDPs.     

A novel quinoxaline bearing electroactive monomer: Pyrrole as the donor moiety

A novel electroactive monomer 5,8-di(1H-pyrrol-2-yl)-2,3-di(thiophen-2-yl)quinoxaline (PTQ) was successfully synthesized and its electrochromic properties were reported. Nuclear magnetic resonance (¹H NMR-¹³C NMR) and mass spectroscopy were used to characterize the monomer. The monomer was electrochemically polymerized in the presence of tetrabutylammonium perchlorate (TBAP) as supporting electrolyte in dichloromethane. Monomer reveals relatively low oxidation potential at +0.70 V. Spectroelectrochemical behaviors and switching ability of homopolymer were investigated by UV-vis spectroscopy and cyclic voltammetry. Two π-π* transitions were observed at 400 and 815 nm with a low band gap, 1.0 eV. Polymer possesses 66% optical contrast in the Near IR region, which may be promising in NIR electrochromic device applications.     

Investigation of vocal jitter and glottal flow spectrum as possible cues for depression and near-term suicidal risk

Among the many clinical decisions that psychiatrists must make, assessment of a patient's risk of committing suicide is definitely among the most important, complex, and demanding. When reviewing his clinical experience, one of the authors observed that successful predictions of suicidality were often based on the patient's voice independent of content. The voices of suicidal patients judged to be high-risk near-term exhibited unique qualities, which distinguished them from nonsuicidal patients. We investigated the discriminating power of two excitation-based speech parameters, vocal jitter and glottal flow spectrum, for distinguishing among high-risk near-term suicidal, major depressed, and nonsuicidal patients. Our sample consisted of ten high-risk near-term suicidal patients, ten major depressed patients, and ten nondepressed control subjects. As a result of two sample statistical analyses, mean vocal jitter was found to be a significant discriminator only between suicidal and nondepressed control groups (p < 0.05). The slope of the glottal flow spectrum, on the other hand, was a significant discriminator between all three groups (p < 0.05). A maximum likelihood classifier, developed by combining the a posteriori probabilities of these two features, yielded correct classification scores of 85% between near-term suicidal patients and nondepressed controls, 90% between depressed patients and nondepressed controls, and 75% between near-term suicidal patients and depressed patients. These preliminary classification results support the hypothesized link between phonation and near-term suicidal risk. However, validation of the proposed measures on a larger sample size is necessary.     

The fast recursive computation of Tchebichef moment and its inverse transform based on Z-transform

The outputs of cascaded digital filters operating as accumulators are combined with a simplified Tchebichef polynomials to form Tchebichef moments (TMs). In this paper, we derive a simplified recurrence relationship to compute Tchebichef polynomials based on Z-transform properties. This paves the way for the implementation of second order digital filter to accelerate the computation of the Tchebichef polynomials. Then, some aspects of digital filter design for image reconstruction from TMs are addressed. The new proposed digital filter structure for reconstruction is based on the 2D convolution between the digital filter outputs used in the computation of the TMs and the impulse response of the proposed digital filter. They operate as difference operators and accordingly act on the transformed image moment sets to reconstruct the original image. Experimental results show that both the proposed algorithms to compute TMs and inverse Tchebichef moments (ITMs) perform better than existing methods in term of computation speed.     

Effect of monolithic zirconia on the degree of conversion of two resin cements analyzed by FT-IR/ATR spectroscopy

Objective: This study aimed to evaluate the degree of conversion (DC) of two different resin cements polymerized under the monolithic zirconia specimens in different thicknesses and colors.

Material and methods: Partially stabilized monolithic zirconia blocks (inCoris TZI) were cut into three different thicknesses (0.5, 1.0, and 2.0 mm) and the specimens were divided into four color groups (A1, A2, A3, and A4). The light transmittance of each specimen was measured. Panavia F 2.0 or Variolink N resin cement was applied into teflon mold and irradiated using the light emitting diode curing unit for 20 s under monolithic zirconia specimen (n = 10). The resin cement specimens were stored at room temperature under dry conditions. The DC of each specimen was measured by Fourier transform infrared-attenuated total reflection (FT-IR/ATR) spectroscopy after the 1st and 10th day. Data were analyzed with two-way analysis of variance (ANOVA), two-way repeated measures ANOVA, three-way repeated measures ANOVA, and the Tukey least significant difference (LSD) tests (α = 0.05).

Results: The light-cure resin cement groups showed higher DC than the dual-cure resin cement groups (p < 0.05). The DC of both resin cements reduced with an increase in the thickness and darkening of the color of monolithic zirconia specimens. There was a statistically meaningful increase in the 10th-day values for dual-cure resin cement (p < 0.05), whereas there were no significant differences between the 1st- and 10th-day values for light-cure resin cement (p > 0.05).

Conclusion: The use of light-cure resin cement can be suggested for the luting of monolithic zirconia restorations.     

Evaluation of the shear bond strength of two resin cements on different CAD/CAM materials

Objective: This study investigated the bond strength of two resin cements (Panavia F 2.0 and Multilink N) to different CAD/CAM materials: resin nanoceramic (RNC; Lava Ultimate), hybrid ceramic (HC; Vita Enamic), zirconia-reinforced lithium silicate ceramic (ZLDC; Vita Suprinity), and lithium disilicate glass-ceramic (LDG; IPS e.max CAD HT).

Material and methods: CAD/CAM blocks of 2-mm thickness were sectioned with a slow-speed diamond-saw sectioning machine. The slabs were then embedded in autopolymerizing acrylic resin (n = 12), and resin cements were applied to the surface of the specimens. All specimens were stored in water for 24 h and subjected to 5000 thermal cycles. Bond strength was measured by means of the shear bond strength test. The data were statistically analyzed by two-way ANOVA and Tukey LSD post hoc tests.

Results: The results of the two-way ANOVA test indicated that the bond strength values varied significantly depending on the CAD/CAM restorative materials, resin cements, and interaction of these variables (p < 0.05). The RNC group showed the highest bond strength for Panavia F 2.0 (p < 0.05); there were no significant differences among other CAD/CAM materials for Panavia F 2.0 (p > 0.05). The LDG group showed the highest bond strength for Multilink N, it was followed by the ZLDC group (p < 0.05); there were no significant differences between RNC and HC groups (p > 0.05).

Conclusions: Choosing resin cements for restorations should be done carefully because bond strength values vary significantly depending on the resin cement and CAD/CAM restorative material.     

Reconsidering stress and smoking: a qualitative study among college students

Background

Although it is widely acknowledged among adult smokers that increases in smoking are often precipitated by stressful events, far less attention has been given to smoking during times of stress among youth.

Aims

To address this gap by drawing attention to the social utility of smoking in contexts associated with stress among college students.

Design

Face‐to‐face semistructured interviews with college freshmen at a large midwestern university in the US.

Participants

Male and female low‐level smokers (n = 24), defined as those who reported regular weekday smoking (typically 3–4 cigarettes a day) and smoking at parties on weekends, were interviewed once in person. In addition, 40 brief interviews with smokers were conducted during final examination.

Measurements

Interviews focused on a range of issues including current smoking behaviour and reasons for smoking. As part of the interview, students were given a deck of cards that listed a range of reasons for smoking. Participants were asked to select cards that described their smoking experience in the past 2 weeks. Those who selected cards that indicated smoking when stressed were asked to explain the reasons why they did so.

Results

A review of qualitative responses reveals that smoking served multiple functions during times of stress for college students. Cigarettes are a consumption event that facilitates a brief social interaction during study times when students feel isolated from their friends. Cigarettes also serve as an idiom of distress, signalling non‐verbally to others that they were stressed. Students described smoking to manage their own stress and also to help manage “second‐hand stress” from their friends and classmates.

Conclusions

Moving away from an individual‐focused analysis of stress to a broader assessment of the social contexts of smoking provides a more nuanced account of the multifunctionalilty of cigarettes in students'' lives. Qualitative research draws attention to issues including the need for smoking and socialising during examination time, smoking as a way to take a break and refocus, notions of second‐hand stress and smoking to manage social relationships.In the past decade, several US‐based studies have reported significant levels of smoking among college students, with approximately 30% of college students reporting having smoked in the past 30 days, and 40% reporting having smoked in the past year.^1,2 Studies have found that a majority of college students who smoke are social smokers, meaning that they smoke more often with others than when alone, particularly when drinking, and that they smoke at low levels.^3,4 To understand better the patterns of low‐level tobacco use, qualitative research was conducted to examine closely the contexts in which students smoked. It has been suggested that a better understanding of the social context of smoking may help enhance tobacco control research and practice.⁵ Two broad contexts that begged consideration were positive social contexts in which tobacco use occurred (such as parties where alcohol was consumed), and contexts associated with stress, be this stressful life events (such as the taking of exams) or stressful events related to the management of social relationships and shifts in identity at this time of transition in life.This article highlights major findings of qualitative research on smoking in contexts associated with stress among college students. It is well established in the general population that increases in smoking are often precipitated by stressful events.^6,7 We draw attention to the social utility of smoking in contexts associated with stress, acknowledging that tobacco use also has psychological and physiological effects when used as a form of stress management and self‐medication.Three major issues guided the research: (1) to explore the extent to which students use smoking as a multifunctional tool for stress management; (2) to determine whether students use smoking as an idiom of distress and a means of showing empathy when a friend is under stress; and (3) to provide details on the complex of motivations that lead students to smoke during examination time.     

Electrospun nanofibers from cyclodextrin inclusion complexes with cineole and p‐cymene: enhanced water solubility and thermal stability

The electrospinning of self‐standing nanofibrous webs from inclusion complexes (IC) of cineole and p‐cymene with two modified cyclodextrins (HPβCD, HPγCD) was achieved without using carrier polymeric matrix. Although they are highly volatile, certain amount of cineole and p‐cymene was protected in cyclodextrin inclusion complexes nanofibers (CD‐IC‐NF). That is, 68.4%, 78.1%, 54.5% and 44.0% (w/w) of active agent were preserved in cineole/HPβCD‐IC‐NF, cineole/HPγCD‐IC‐NF, p‐cymene/HPβCD‐IC‐NF and p‐cymene/HPγCD‐IC‐NF, respectively. Remarkable, high thermal stability for cineole (~150 °C – 270 °C) and p‐cymene (~150 °C – 275 °C) was achieved for CD‐IC‐NF samples due to CD‐IC formation. The water solubility of cineole and p‐cymene was significantly improved by inclusion complexation where CD‐IC‐NF samples become readily dissolved in water. In brief, essential oils and flavours such as cineole and p‐cymene could be applicable in food and oral care applications owing to their fast‐dissolving behaviour along with high water solubility, enhanced thermal stability and free‐standing feature of CD‐IC‐NF webs.