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Here we contrast the stability of monomeric and photopolymerized self-assembled monolayers (SAMs) containing a diacetylene group (HS(CH 2 ) 10 CtCCtC(CH 2 ) 10 COOH) with SAMs prepared from simple n-alkanethiols. The polymerized SAMs are extremely durable compared to either the n-alkanethiol SAMs or the unpolymerized diacetylenic SAMs. For example, they are stable to repeated electrochemical cycling to extreme potentials, thermal excursions to 200°C, and exposure to hot base (1:1 mixture of ethanol and 1.0 M aqueous KOH at 100°C). All of these conditions completely strip n-alkanethiol SAMs from Au substrates. These high-performance materials are suitable for applications in lubrication, adhesion, corrosion passivation, and chemical sensing.

Here we discuss the preparation and characterization of photopolymerizable, self-assembled monolayers (SAMs) that consist of acid-, hydroxyl-, and methyl-terminated n-alkanethiols containing a diacetylene group (HS(CH2)10CtCCtC(CH2)10X; X ) COOH, CH2OH, and CH3, respectively). The acid and hydroxyl surfaces are readily amenable to further synthetic elaboration, while the methyl-terminated SAM results in a clean, low-energy surface. As demonstrated by Fourier transform infrared external reflectance spectroscopy (FTIR-ERS), surface-enhanced Raman spectroscopy (SERS), ellipsometry, UV-vis spectroscopy, and electrochemical methods, all three materials self assemble onto Au surfaces to form ordered monolayers that can be photopolymerized with UV light.

The purpose was to examine the agreement (convergent validity) between six common measures of habitual physical activity to estimate durations of light, moderate, vigorous, and total activity in a range of free-living individuals. Over 7 consecutive days, 49 ethnic Chinese (30 men, 19 women), aged 15-55 yr, wore a Polar heart rate monitor, a uniaxial MTI, and triaxial Tritrac accelerometer, plus a Yamax pedometer for > or = 600 min/day. They also completed a daily physical activity log and on day 8 a Chinese version of the 7-day International Physical Activity Questionnaire. At each level of activity, there was good agreement between the two questionnaire-derived instruments and the two accelerometry-derived instruments, but wide variation across different instruments, with two- to fourfold differences in mean durations often seen. The heart rate monitor overestimated light activity and underestimated moderate activity compared with all other measures. Spearman correlation coefficients were low to moderate (0.2-0.5) across most measures of activity, with the pedometer showing correlations with total activity that were often superior to the other movement sensors. We conclude that, with the use of commonly accepted cut points for defining light, moderate, vigorous, and total activity, little convergent validity across the instruments was evident, suggesting these measures are sampling different levels of habitual physical activity and care is needed when comparing their results. To provide a more stable comparison of activity among different people, across studies, or against accepted physical activity promotion guidelines, further work is needed to fine tune the different cut points across a range of common activity monitors to provide more consistent results during free-living conditions.

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A rational design strategy was used to construct a sensitive "turn-on" biosensor for beta-lactam antibiotics and beta-lactamase inhibitors from a class A beta-lactamase mutant with suppressed hydrolytic activity. A fluorescein molecule was attached to the 166 position on the Omega-loop of the E166C mutant close to the active site of the beta-lactamase. Upon binding with antibiotics or inhibitors, the flexibility of the Omega-loop allows the fluorescein molecule to move out from the active site and be more exposed to solvent. This process is accompanied by an increase in the fluorescence of the labeled enzyme. The fluorescence intensity of the biosensor increases with the concentration of antibiotics or inhibitors, which can detect penicillin G at concentrations as low as 50 nM in water. This approach opens a possibility for converting highly active and nonallosteric enzymes into substrate-binding proteins for biosensing purposes.

Self-efficacy has been consistently found to be a protective factor against psychological distress and disorders in the literature. However, little research is done on the moderating effect of self-efficacy on depressive symptoms in the context of chronic pain. This cross-sectional study aimed to examine if pain self-efficacy attenuated the direct relationship between pain intensity and depressive symptoms, as well as their indirect relationship through reducing the extent of catastrophizing when feeling pain (moderated mediation). 664 community-dwelling Chinese older adults aged 60–95 years who reported chronic pain for at least three months were recruited from social centers. They completed a battery of questionnaires on chronic pain, pain self-efficacy, catastrophizing, and depressive symptoms in individual face-to-face interviews. Controlling for age, gender, education, self-rated health, number of chronic diseases, pain disability, and pain self-efficacy, pain catastrophizing was found to partially mediate the connection between pain intensity and depressive symptoms. Furthermore, the relationship between pain intensity and depressive symptoms was moderated by pain self-efficacy. Self-efficacy was also found to moderate the relationship between pain intensity and catastrophizing and the moderated mediation effect was confirmed using bootstrap analysis. The results suggested that with increasing levels of self-efficacy, pain intensity’s direct effect on depressive symptoms and its indirect effect on depressive symptoms via catastrophizing were both reduced in a dose-dependent manner. Our findings suggest that pain self-efficacy is a significant protective factor that contributes to psychological resilience in chronic pain patients by attenuating the relationship of pain intensity to both catastrophizing and depressive symptoms.

The World Health Organization considered the widespread of COVID-19 over the world as a pandemic. There is still a lack of understanding of its origin, transmission, and treatment methods. Understanding the influencing factors of the COVID-19 can help mitigate its spread, but little research on the spatial factors has been conducted. Therefore, this study explores the effects of urban geometry and socio-demographic factors on the COVID-19 cases in Hong Kong. For each patient, the places they visited during the incubation period before going to hospital were identified, and matched with corresponding attributes of urban geometry (i.e., building geometry, road network, greenspace) and socio-demographic factors (i.e., demographic, educational, economic, household and housing characteristics) based on the coordinates. The local cases were then compared with the imported cases using the stepwise logistic regression, the logistic regression with case-control of time, and the least absolute shrinkage and selection operator regression to identify factors influencing local disease transmission. Results show that the building geometry, road network and certain socio-economic characteristics are significantly associated with COVID-19 cases. In addition, the results indicate that urban geometry is playing a more important role than the socio-demographic characteristics in affecting the COVID-19 incidences. These findings provide a useful reference to the government and the general public as to the spatial vulnerability of the COVID-19 transmission and to take appropriate preventive measures in high-risk areas.