Explaining System Missing

Missing values are nearly inescapable within social science research. The problem of missing data is especially troubling in longitudinal and intensive longitudinal studies when participants miss an entire collection cycle compared to item nonresponse. The present study examines some of the contextual influences of missed study participation using unobtrusive measures of experience in conjunction with the experience sampling method (ESM). A sample of 66 participants generated 2,940 observations across a 7-day study, yielding a missing response rate of 34%. Multilevel binary logistic regression was used to estimate the probability of missing the study participation signal based upon study time and physical activity states. Results indicate that the probability of missing collection signals increases throughout the duration of the study and with high levels of physical activity. The strongest predictor of missed participation occurred when participants’ activity monitors were set to “asleep” mode. Implications of these findings and recommendations for future ESM studies are discussed.

Lay Definitions of Happiness across Nations: The Primacy of Inner Harmony and Relational Connectedness

In well-being research the term happiness is often used as synonymous with life satisfaction. However, little is known about lay people's understanding of happiness. Building on the available literature, this study explored lay definitions of happiness across nations and cultural dimensions, analyzing their components and relationship with participants' demographic features. Participants were 2799 adults (age range = 30-60, 50% women) living in urban areas of Argentina, Brazil, Croatia, Hungary, India, Italy, Mexico, New Zealand, Norway, Portugal, South Africa, and United States. They completed the Eudaimonic and Hedonic Happiness Investigation (EHHI), reporting, among other information, their own definition of happiness. Answers comprised definitions referring to a broad range of life domains, covering both the contextual-social sphere and the psychological sphere. Across countries and with little variation by age and gender, inner harmony predominated among psychological definitions, and family and social relationships among contextual definitions. Whereas relationships are widely acknowledged as basic happiness components, inner harmony is substantially neglected. Nevertheless, its cross-national primacy, together with relations, is consistent with the view of an ontological interconnectedness characterizing living systems, shared by several conceptual frameworks across disciplines and cultures. At the methodological level, these findings suggest the potential of a bottom-up, mixed method approach to contextualize psychological dimensions within culture and lay understanding.

Effects of biosurfactants, mannosylerythritol lipids, on the hydrophobicity of solid surfaces and infection behaviours of plant pathogenic fungi

AIMS

To investigate the effects of mannosylerythritol lipids (MELs) on the hydrophobicity of solid surfaces, their suppressive activity against the early infection behaviours of several phytopathogenic fungal conidia, and their suppressive activity against disease occurrences on fungal host plant leaves.

METHODS AND RESULTS

The changes in the hydrophobicity of plastic film surfaces resulting from treatments with MEL solutions (MEL-A, MEL-B, MEL-C and isoMEL-B) and synthetic surfactant solutions were evaluated based on the changes in contact angles of water droplets placed on the surfaces. The droplet angles on surfaces treated with MELs were verified to decrease within 100 s after placement, with contact angles similar to those observed on Tween 20-treated surfaces, indicating decreases in surface hydrophobicity after MEL treatments. Next, conidial germination, germ tube elongation and the formation of appressorium of Blumeria graminis f. sp. tritici, Colletotrichum dematium, Glomerella cingulata and Magnaporthe grisea were evaluated on plastic surfaces that were pretreated with surfactant solutions. On the surfaces of MEL-treated plastic film, inhibition of conidial germination, germ tube elongation, and suppression of appressoria formation tended to be observed, although the level of effect was dependent on the combination of fungal species and type of MEL. Inoculation tests revealed that the powdery mildew symptom caused by B. graminis f. sp. tritici was significantly suppressed on wheat leaf segments treated with MELs.

CONCLUSIONS

MELs exhibited superior abilities in reducing the hydrophobicity of solid surfaces, and have the potential to suppress powdery mildew in wheat plants, presumably due to the inhibition of conidial germination.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides significant evidence of the potential for MELs to be used as novel agricultural chemical pesticides.

Cotton-wool-like bioactive glasses for bone regeneration

Inorganic sol-gel solutions were electrospun to produce the first bioactive three-dimensional (3-D) scaffolds for bone tissue regeneration with a structure like cotton-wool (or cotton candy). This flexible 3-D fibrous structure is ideal for packing into complex defects. It also has large inter-fiber spaces to promote vascularization, penetration of cells and transport of nutrients throughout the scaffold. The 3-D fibrous structure was obtained by electrospinning, where the applied electric field and the instabilities exert tremendous force on the spinning jet, which is required to be viscoelastic to prevent jet break up. Previously, polymer binding agents were used with inorganic solutions to produce electrospun composite two-dimensional fibermats, requiring calcination to remove the polymer. This study presents novel reaction and processing conditions for producing a viscoelastic inorganic sol-gel solution that results in fibers by the entanglement of the intermolecularly overlapped nanosilica species in the solution, eliminating the need for a binder. Three-dimensional cotton-wool-like structures were only produced when solutions containing calcium nitrate were used, suggesting that the charge of the Ca(2+) ions had a significant effect. The resulting bioactive silica fibers had a narrow diameter range of 0.5-2μm and were nanoporous. A hydroxycarbonate apatite layer was formed on the fibers within the first 12h of soaking in simulated body fluid. MC3T3-E1 preosteoblast cells cultured on the fibers showed no adverse cytotoxic effect and they were observed to attach to and spread in the material.

A novel ligation forceps can be used as a ligature carrier and knot pusher during laparoscopic surgery

BACKGROUND

To extend the usefulness of laparoscopic operations, a secure and easy method for the ligation of large vessels is needed. Herein we describe a novel ligation forceps that can be used as a ligature carrier and knot pusher.

METHODS

A 2-0 suture thread with a knot already tied near one end is hooked in the upper jaw of a novel ligation forceps. After the lower jaw is passed under the vessel or cystic duct, the forceps is closed. When one end of the thread is withdrawn, the knot is trapped in the indentation built into the lower jaw; the ligature is then passed under the pedicle. An extracorporeal ligation can then be performed continuously by the same forceps.

RESULTS

The origins of large vessels were ligated safely and easily with this device during 65 laparoscopic procedures (four total colectomies, 12 colectomies, and 49 gastrectomies). Following temporary hemostasis of accidental bleeding with clamping forceps, ligation hemostasis can also be performed using this instrument.

CONCLUSION

This novel ligation forceps permits the secure ligation of vessels or a cystic duct without the need for another device. The proposed method is both easy and inexpensive.

Does flow experience lead to risk? How and for whom

BACKGROUND

Previous research has focused on the positive consequences of flow, an intrinsically rewarding state of deep absorption. In contrast, the present research links flow to impaired risk awareness and to risky behaviour. We expected flow to enhance self-efficacy beliefs, which in turn were hypothesised to result in low risk awareness and risky behaviour in sports. In addition, we predicted that individuals' level of experience in the activity would moderate the expected effects.

METHODS

One study with kayakers (Study 1) and two studies with rock climbers (Studies 2 and 3) were conducted. Kayakers completed a survey while still on the river; climbers responded during and upon completion of a climb.

RESULTS

In all studies flow was related to risk awareness. Study 2 additionally showed its association with risky behaviour. Studies 2 and 3 revealed that these relationships were mediated by self-efficacy. The mediations were moderated by level of experience (Study 3).

CONCLUSIONS

The results indicated that inexperienced but not experienced participants respond to self-efficacy beliefs evoked by flow with impaired risk awareness and with risky behaviour. Theoretical implications for flow and risk research as well as practical implications for risk prevention are discussed.

Angiogenic activity of subchondral bone during the progression of osteoarthritis in a rabbit anterior cruciate ligament transection model

OBJECTIVE

To investigate the longitudinal angiogenic activity of subchondral bone and cartilage during the progression of osteoarthritis (OA) using a rabbit model of OA.

MATERIALS AND METHODS

OA was surgically induced by anterior cruciate ligament transaction (ACLT) in left knee of 12 months old female New Zealand white rabbits (n = 33). Histological examination, immunohistochemistry, and angiogenic activity assay was done at 0, 2, 4, 6, 8, 12 weeks after ACLT. Histologic evaluation was performed with haematoxylin and eosin, safranin-O staining to assess the OA change of medial femoral condyle (MFC) and lateral femoral condyle (LFC). CD31 immunohistochemistry was performed to confirm the vascular invasion at osteochondral junction. A co-cultured tubule formation assay was conducted to evaluate angiogenic activity of the subchondral bone and cartilage of MFC and LFC as well as synovium. Association between histological changes, angiogenic activity, and vascular invasion were evaluated.

RESULTS

OA changes increased in a time-dependent manner both in MFC and LFC. Angiogenic activity of subchondral bone showed a monomodal change during the OA progression, achieved a peak in the early to progressive stage and decreased to normal level in the late stage of OA. Surge of vascular invasion was observed following the increase of angiogenic activity in the progressive stage of OA. Angiogenic activity of cartilage did not change during the course of OA progression.

CONCLUSION

Angiogenic activity of subchondral bone was elevated in the early to progressive stage of OA and vascular invasion into the osteochondral junction followed.

Genetic and environmental influences on the relationship between flow proneness, locus of control and behavioral inhibition

Flow is a psychological state of high but subjectively effortless attention that typically occurs during active performance of challenging tasks and is accompanied by a sense of automaticity, high control, low self-awareness, and enjoyment. Flow proneness is associated with traits and behaviors related to low neuroticism such as emotional stability, conscientiousness, active coping, self-esteem and life satisfaction. Little is known about the genetic architecture of flow proneness, behavioral inhibition and locus of control--traits also associated with neuroticism--and their interrelation. Here, we hypothesized that individuals low in behavioral inhibition and with an internal locus of control would be more likely to experience flow and explored the genetic and environmental architecture of the relationship between the three variables. Behavioral inhibition and locus of control was measured in a large population sample of 3,375 full twin pairs and 4,527 single twins, about 26% of whom also scored the flow proneness questionnaire. Findings revealed significant but relatively low correlations between the three traits and moderate heritability estimates of .41, .45, and .30 for flow proneness, behavioral inhibition, and locus of control, respectively, with some indication of non-additive genetic influences. For behavioral inhibition we found significant sex differences in heritability, with females showing a higher estimate including significant non-additive genetic influences, while in males the entire heritability was due to additive genetic variance. We also found a mainly genetically mediated relationship between the three traits, suggesting that individuals who are genetically predisposed to experience flow, show less behavioral inhibition (less anxious) and feel that they are in control of their own destiny (internal locus of control). We discuss that some of the genes underlying this relationship may include those influencing the function of dopaminergic neural systems.

Possible association of nicotinic acetylcholine receptor gene (CHRNA4 and CHRNB2) polymorphisms with nicotine dependence in Japanese males: an exploratory study

INTRODUCTION

Smoking is a leading global cause of avoidable mortality. It has been reported that the nicotinic acetylcholine receptor (CHRNA4 and CHRNB2) genes might be associated with smoking behavior in several ethnic populations. However, no study between the 2 genes and nicotine dependence (ND) using a Japanese population has been reported.

METHODS

We examined the association between ND and 5 single nucleotide polymorphisms (SNPs) within the CHRNA4 and 3 SNPs within the CHRNB2 using a well characterized sample of 558 Japanese healthy male workers with a relatively homogeneous background. The Fagerström test for nicotine dependence (FTND) was used to quantify the degree of ND. Additionally, we explored the effect of gene-gene interactions of the 2 genes on ND.

RESULTS

We found CHRNB2 rs4845652 genotypes to be associated with FTND scores under an additive genetic model: rs4845652 T-allele carriers had lower ND levels (p=0.038; when adjusted for smoking duration: p=0.052). Furthermore, we demonstrated a possible gene-gene interaction of CHRNA4 and CHRNB2 on ND in a dose-dependent manner: those smokers with CHRNA4 rs1044397 GG or GA genotypes along with CHRNB2 rs4845652 CC genotype are likely to demonstrate higher ND scores.

DISCUSSION

These findings suggest that CHRNB2 rs4845652 T-allele carriers may be associated with lower levels of ND, and that certain allelic combinations of CHRNA4 and CHRNB2 might be correlated with higher ND levels. This preliminary study has certain limitations (issues such as sample size/power and multiple testing) that need to be taken into account, and the present work thus has an experimental nature.