Thermodynamically Driven Formation of Intercalated Cu Carpets from Supported Cu Pyramids on MoS2.

Thermodynamic and kinetic analyses based on our first-principles density functional theory calculations are used to interpret the experimentally observed formation of Cu carpets intercalated under the top layer of a 2H-MoS2 substrate. Spontaneous Cu transport from Cu pyramids on top of the MoS2 substrate through surface point defects to the growing Cu carpet is shown to be driven by a slightly lower chemical potential for the Cu carpet. We demonstrate that the competition between a preference for a thicker Cu carpet and the cost of elastic stretching of the top MoS2 layer results in a selected Cu carpet thickness. We also propose that Cu transport occurs primarily via vacancy-mediated diffusion through constricting point defect portals.

Phase transitions in Schloegl's second model for autocatalysis on a Bethe lattice.

Schloegl's second model (also known as the quadratic contact process) on a lattice involves spontaneous particle annihilation at rate p and autocatalytic particle creation at empty sites with n≥2 occupied neighbors. The particle creation rate for exactly n occupied neighbors is selected here as n(n-1)/[z(z-1)] for lattice coordination number z. We analyze this model on a Bethe lattice. Precise behavior for stochastic models on regular periodic infinite lattices is usually surmised from kinetic Monte Carlo simulation on a finite lattice with periodic boundary conditions. However, the persistence of boundary effects for a Bethe lattice complicates this process, e.g., by inducing spatially heterogenous states. This motivates the exploration of various boundary conditions and unconventional simulation ensembles on the Bethe lattice to predict behavior for infinite size. We focus on z=3, and predict a discontinuous transition to the vacuum state on the infinite lattice when p exceeds a threshold value of around 0.053.

Extended families of critical and stationary droplets for nonequilibrium phase transitions in spatially discrete bistable systems.

Bistable nonequilibrium systems are realized in catalytic reaction-diffusion processes, biological transport and regulation, spatial epidemics, etc. Behavior in spatially continuous formulations, described at the mean-field level by reaction-diffusion type equations (RDEs), often mimics that of classic equilibrium van der Waals type systems. When accounting for noise, similarities include a discontinuous phase transition at some value, p_{eq}, of a control parameter, p, with metastability and hysteresis around p_{eq}. For each p, there is a unique critical droplet of the more stable phase embedded in the less stable or metastable phase which is stationary (neither shrinking nor growing), and with size diverging as p→p_{eq}. Spatially discrete analogs of these mean-field formulations, described by lattice differential equations (LDEs), are more appropriate for some applications, but have received less attention. It is recognized that LDEs can exhibit richer behavior than RDEs, specifically propagation failure for planar interphases separating distinct phases. We show that this feature, together with an orientation dependence of planar interface propagation also deriving from spatial discreteness, results in the occurrence of entire families of stationary droplets. The extent of these families increases approaching the transition and can be infinite if propagation failure is realized. In addition, there can exist a regime of generic two-phase coexistence where arbitrarily large droplets of either phase always shrink. Such rich behavior is qualitatively distinct from that for classic nucleation in equilibrium and spatially continuous nonequilibrium systems.

Discontinuous Phase Transitions in Nonlocal Schloegl Models for Autocatalysis: Loss and Reemergence of a Nonequilibrium Gibbs Phase Rule.

We consider Schloegl models (or contact processes) where particles on a square grid annihilate at a rate p and are created at a rate of k_{n}=n(n-1)/[N(N-1)] at empty sites with n particles in a neighborhood Ω_{N} of size N. Simulation reveals a discontinuous transition between populated and vacuum states, but equistable p=p_{eq} determined by the stationarity of planar interfaces between these states depends on the interface orientation and on Ω_{N}. The behavior for large Ω_{N} follows from continuum equations. These also depend on the interface orientation and on Ω_{N} shape, but a unique p_{eq}=0.211 376 320 4 emerges imposing a Gibbs phase rule.

Phosphoenolpyruvate phosphotransferase system components positively regulate Klebsiella biofilm formation.

BACKGROUND/PURPOSE: Klebsiella pneumoniae is one of the leading causes of device-related infections (DRIs), which are associated with attachment of bacteria to these devices to form a biofilm. The latter is composed of not only bacteria but also extracellular polymeric substances (EPSes) consisting of extracellular DNAs, polysaccharides, and other macromolecules. The phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) regulates diverse processes of bacterial physiology. In the genome of K. pneumoniae MGH 78578, we found an uncharacterized enzyme II complex homolog of PTS: KPN00353 (EIIA homolog), KPN00352 (EIIB homolog), and KPN00351 (EIIC homolog). The aim of this study was to characterize the potential physiological role of KPN00353, KPN00352, and KPN00351 in biofilm formation by K. pneumoniae. METHODS/RESULTS: We constructed the PTS mutants and recombinant strains carrying the gene(s) of PTS. The recombinant K. pneumoniae strain overexpressing KPN00353-KPN00352-KPN00351 produced more extracellular matrix than did the vector control according to transmission and scanning electron microscopy. Judging by quantification of biofilm formation, of extracellular DNA (eDNA), and of capsular polysaccharide, the recombinant strain overexpressing KPN00353-KPN00352-KPN00351 produced more biofilm and capsular polysaccharide after overnight culture and more eDNA in the log phase as compared to the vector control. CONCLUSION: The genes, KPN00353-KPN00352-KPN00351, encode a putative enzyme II complex in PTS and positively regulate biofilm formation by enhancing production of eDNA and capsular polysaccharide in K. pneumoniae. Five proteins related to chaperones, to the citric acid cycle, and to quorum sensing are upregulated by the KPN00353-KPN00352-KPN00351 system.

The Chinese family-centered care survey for adult intensive care unit: A psychometric study.

AIMS: This study aimed to develop a family-centered care survey for Chinese adult intensive care units and to establish the survey's psychometric properties. BACKGROUND: Family-centered care (FCC) is widely recognized as an ideal model of care. Few studies have explored FCC perceptions among family members of adult critical care patients in Asian countries, and no Chinese FCC measurement has been developed. METHODS: An English version of the 3-factor family-centered care survey for adult intensive care units (FCCS-AICU) was translated into Chinese using a modified back translation procedure. Based on the literature review, two additional concepts, information and empowerment, were added to the Chinese FCCS-AICU. The psychometric properties of the Chinese FCCS-AICU were determined with 249 family members from a medical center in Taiwan and were tested for construct and convergent validity, and internal consistency. RESULTS: Both the monolingual and bilingual equivalence tests of the English and Chinese versions of the 3-factor FCCS-AICU were supported. Exploratory factor analysis supported the 5-factor structure of the Chinese FCCS-AICU with a total explained variance of 58.34%. The Chinese FCCS-AICU was correlated with the Chinese Critical Care Family Needs Inventory. Internal consistency, determined by Cronbach's α, for the overall scale was .94. CONCLUSIONS: The Chinese FCCS-AICU is a valid and reliable tool for measuring perceptions of FCC by family members of adult intensive care patients within Chinese-speaking communities.

Discontinuous non-equilibrium phase transition in a threshold Schloegl model for autocatalysis: Generic two-phase coexistence and metastability.

Threshold versions of Schloegl's model on a lattice, which involve autocatalytic creation and spontaneous annihilation of particles, can provide a simple prototype for discontinuous non-equilibrium phase transitions. These models are equivalent to so-called threshold contact processes. A discontinuous transition between populated and vacuum states can occur selecting a threshold of N ≥ 2 for the minimum number, N, of neighboring particles enabling autocatalytic creation at an empty site. Fundamental open questions remain given the lack of a thermodynamic framework for analysis. For a square lattice with N = 2, we show that phase coexistence occurs not at a unique value but for a finite range of particle annihilation rate (the natural control parameter). This generic two-phase coexistence also persists when perturbing the model to allow spontaneous particle creation. Such behavior contrasts both the Gibbs phase rule for thermodynamic systems and also previous analysis for this model. We find metastability near the transition corresponding to a non-zero effective line tension, also contrasting previously suggested critical behavior. Mean-field type analysis, extended to treat spatially heterogeneous states, further elucidates model behavior.

Langevin and fOkker-Planck analyses of inhibited molecular passing processes controlling transport and reactivity in nanoporous materials.

Inhibited passing of reactant and product molecules within the linear pores of nanoporous catalytic materials strongly reduces reactivity. The dependence of the passing propensity P on pore radius R is analyzed utilizing Langevin dynamics to account for solvent effects. We find that P ∼ (R-R(c))(σ), where passing is sterically blocked for R≤R(c), with σ below the transition state theory value. Deeper insight comes from analysis of the corresponding high-dimensional Fokker-Planck equation, which facilitates an effective small-P approximation, and dimensional reduction enabling utilization of conformal mapping ideas. We analyze passing for spherical molecules and also assess the effect of rotational degrees of freedom for elongated molecules.

Low socioeconomic status may increase the risk of central obesity in incoming university students in Taiwan.

BACKGROUND: Obesity is related to social disparity. The objective of the study was to evaluate different indicators of parental SES with the association of central obesity in young adult Taiwanese students. METHODS: This study was cross-sectionally designed and a total of 4552 subjects were recruited. Each subject completed a self-administrated questionnaire and received anthropometric and laboratory measurements. The indicators of SES in study subjects included parental education, occupation, household incomes, childhood and current index of social position (ISP), measured according to the modified Hollingshead's ISP. Central obesity was defined as waist circumference ≥90 cm in men and ≥80 cm in women. RESULTS: The prevalence of central obesity was 10.7% in this study. When compared to subjects with normal waist circumferences, subjects with central obesity were older, had a higher BMI, both systolic and diastolic blood pressure, a higher proportion of male gender, family history of diabetes and hypertension, alcohol consumption habit, and a higher proportion of low current household income, current parental blue collar occupational level, and lower current and childhood parental ISP level. Multivariate analysis showed the current parental household income and ISP were significantly higher indicators of risk of central obesity after adjustment for possible confounding factors. The odds ratios were 1.26 and 1.30, respectively. CONCLUSIONS: Our results showed that low household income and current ISP were independently associated with the risk of central obesity. Therefore, young adults with low SES should be an important target group for prevention and management of central obesity in school health promotion programs.

Schloegl's second model for autocatalysis on hypercubic lattices: Dimension dependence of generic two-phase coexistence.

Schloegl's second model on a (d ≥ 2)-dimensional hypercubic lattice involves: (i) spontaneous annihilation of particles with rate p and (ii) autocatalytic creation of particles at vacant sites at a rate proportional to the number of suitable pairs of neighboring particles. This model provides a prototype for nonequilibrium discontinuous phase transitions. However, it also exhibits nontrivial generic two-phase coexistence: Stable populated and vacuum states coexist for a finite range, pf(d)

Kindergarten teachers' experience with reporting child abuse in Taiwan.

OBJECTIVE: The objectives were to examine factors associated with reporting child abuse among kindergarten teachers in Taiwan based on the Theory of Planned Behavior (TPB). METHOD: A stratified quota sampling technique was used to randomly select kindergarten teachers in Taiwan. The Child Abuse Intention Report Scale, which includes demographics, attitudes about child discipline, punishment for perpetrators, and professional responsibility for reporting, subjective norms regarding support for reporting from the general and specific important persons, perceived behavioral control, and vignettes of child abuse, was used to collect data. A total of 598 kindergarten teachers (return rate 47%) provided data. RESULTS: While 97% of teachers reported having no experience with reporting a child abuse case, 11% indicated they had failed to report a suspected case of child abuse. Multiple regression revealed that, except for social norms, attitudes toward child discipline, punishments for perpetrators, and professional responsibility as well as perceived behavioral control explained 22.4% of variance of kindergarten teachers' intention to report child abuse. CONCLUSIONS: With the exception of the subjective norms, the findings of this study supported the TPB that kindergarten teachers' intention to report child abuse is associated with attitudes toward child discipline, punishment for perpetrators, professional responsibility, and perceived behavioral controls over reporting. This study revealed the problem of underreporting child abuse among kindergarten teachers in Taiwan, and highlighted the discrepancy between child abuse training and expected reporting outcomes suggesting an insufficiency in the current training programs on child abuse. PRACTICE IMPLICATIONS: There is a need to scrutinize the current training in child abuse and develop standardized training and clear reporting guidelines that will increase kindergarten teachers' confidence when confronted with suspected victims and perpetrators of child abuse in Taiwan.

Comparing knowledge, health beliefs, and self-efficacy toward hepatitis B prevention among university students with different hepatitis B virus infectious statuses.

Hepatitis B carriers are at risk of spreading the virus and developing cirrhosis and hepatoma. The purpose of this study was to examine differences in knowledge, health beliefs, and self-efficacy related to hepatitis B prevention among university students. Using a comparative descriptive design, the study population, defined to include second- through fourth-year students, enrolled at a university in southern Taiwan. Students were stratified by hepatitis B virus infectious status and then selected at random for participation. Survey data were obtained via an online SPSS data entry system. The response rate was 39.9%. A total of 109, 113, and 106 students were assigned, based on their status, to the immune group (having hepatitis B antibody), susceptible group (having neither hepatitis B antigen nor antibody), and carrier group (having hepatitis B antigen without antibody), respectively. Most participants in this study attached a social stigma to hepatitis B carriers. Approximately 24% of carriers and 19% of susceptible students were unaware of their hepatitis B infectious status. Compared with the other two groups, carriers were less likely to change their lifestyle to promote health. Although more than two thirds of susceptible students agreed that their current behavior is risky, only half were worried about becoming hepatitis B carriers. The findings revealed the pressing need for hepatitis B prevention education among university students. School nurses should work closely with school administrators to establish a health promotion program to increase carriers' self-efficacy to promote their personal health, curtail risky behavior among susceptible students, and remove the stigma attached to hepatitis B carriers among university students.

Entry-level skill competency : a comparison of head nurses expectations and new graduates perceptions.

The purpose of this study was to compare the differences between head nurses expectations and new graduates perceptions of the entry-level skill competency. Subjects included 147 new graduates and 126 head nurses from four schools of nursing and their affiliated medical centers located in northern, central and southern Taiwan. The results showed that among 213 skills, 153 skills were reported by over 60% of head nurses to be performed precisely under clinical settings. In contrast to the graduates perceptions, over 60% of the graduates had confidence to perform only 82 skills precisely. The percentage of head nurses expectation and the perception of the graduates in skills that were reported to be performed precisely in clinical situations were significantly different in 145 skills (68%). For seventy-six skill items there was congruence between the percentage of head nurses expectations and new graduates perceptions. The percentage of the head nurses expectation were higher than the graduates perception in 55 skills. On the other hand, for 14 skills the percentage of graduates who perceived themselves as being able to perform them precisely was significantly higher than the percentage of head nurses. The results can be applied to improve nursing skills teaching and students pre-job preparation.