Publications

Salivary amylase, encoded by the <i>AMY1</i> gene, is responsible for the digestion of carbohydrates. We investigated associations of the <i>AMY1</i> genetic variations with general and central adiposity changes considering dietary carbohydrate intake among 32054 adults from 4 prospective cohort studies. A genetic risk score (GRS) was calculated based on nine <i>AMY1</i> single-nucleotide polymorphisms, with higher AMY1-GRS indicating higher activity of salivary amylase. We meta-analyzed interactions between AMY1-GRS and dietary intake for changes in general and central adiposity over 5.5–10 years. We found that carbohydrate food intake significantly altered associations of <i>AMY1</i>-GRS with changes in body mass index (<i>P<sub>interaction</sub></i>=0.001) and waist circumference (<i>P<sub>interaction</sub></i> <0.001). Results were consistent and significant in female cohorts rather than in male cohorts. Among women, higher AMY1-GRS was associated with more increases in adiposity if dietary carbohydrate food intake was high, while higher AMY1-GRS was associated with less gains in adiposity when the dietary intake was low. Also, in a 2-year randomized dietary intervention trial, associations of <i>AMY1</i>-GRS with changes in weight (<i>P<sub>interaction</sub></i>=0.023) and waist circumference (<i>P<sub>interaction</sub></i><sub>=</sub>0.037) were significantly modified by carbohydrate intake. Our results suggest the importance of precision nutrition strategies considering participants’ genetic adaptation to carbohydrate-rich diets in regulating general and central adiposity.

OBJECTIVE To examine racial differences in sleep duration and its relationship with diabetes. RESEARCH DESIGN AND METHODS We used data from a nationally representative sample of U.S. adults (n = 130,943) participating in the National Health Interview Survey from 2004 to 2011. Usual sleep duration was self-reported and categorized as <7 h (short), 7 h (optimal), and >7 h (long). Diabetes status was based on self-reported diagnosis from a health professional. RESULTS Participants’ mean age was 50.6 years, 49% were men, and 13% were black. Compared with whites, blacks were more likely to report short sleep (37 vs. 28%) and less likely to get 7 h of sleep (24 vs. 33%). Diabetes (9,643 cases [9%] in whites and 3,612 cases [15%] in blacks) had a U-shaped distribution with sleep in whites (10, 7, and 9%, for short, optimal, and long sleep, respectively) and blacks (16, 13, and 15%). Suboptimal sleep duration was more strongly associated with diabetes in whites than in blacks among short (prevalence ratio 1.49 [95% CI 1.40–1.58] vs. 1.21 [1.09–1.34]) and long (1.32 [1.25–1.40] vs. 1.11 [1.00–1.23]) sleepers on the relative scale. Adjustment for socioeconomic status (SES) attenuated the short sleep–diabetes association in blacks (1.15 [1.02–1.29]), and the racial/ethnic difference in the short sleep–diabetes association became nonsignificant after SES adjustments. CONCLUSIONS Suboptimal sleep duration was positively associated with diabetes in blacks and whites, although diabetes prevalence was higher at any level of sleep in blacks. Socioeconomic factors appear to partly explain the association for short sleep in blacks as well as disparity between racial groups.

Background— α-Linolenic acid, an intermediate-chain n-3 fatty acid found primarily in plants, may decrease the risk of fatal coronary heart disease (CHD) through a reduction in fatal ventricular arrhythmias and sudden cardiac death (SCD). Methods and Results— We prospectively examined the association between dietary intake of α-linolenic acid assessed via updated food-frequency questionnaires and the risk of SCD, other fatal CHD, and nonfatal myocardial infarction (MI) among 76 763 women participating in the Nurses’ Health Study who were free from cancer and completed a dietary questionnaire at baseline in 1984. During 18 years of follow-up, we identified 206 SCDs, 641 other CHD deaths, and 1604 nonfatal MIs. After controlling for coronary risk factors and other fatty acids, including long-chain n-3 fatty acids, the intake of α-linolenic acid was inversely associated with the risk of SCD ( P for trend, 0.02) but not with the risk of other fatal CHD or nonfatal MI. Compared with women in the lowest quintile of α-linolenic acid intake, those in the highest 2 quintiles had a 38% to 40% lower SCD risk. This inverse relation with SCD risk was linear and remained significant even among women with high intakes of long-chain n-3 fatty acids. Conclusions— These prospective data suggest that increasing dietary intake of α-linolenic acid may reduce the risk of SCD but not other types of fatal CHD or nonfatal MI in women. The specificity of the association between α-linolenic acid and SCD supports the hypothesis that these n-3 fatty acids may have antiarrhythmic properties.

Developing soft circuits from individual soft logic gates poses a unique challenge: with increasing numbers of logic gates, the design and implementation of circuits leads to inefficiencies due to mathematically unoptimized circuits and wiring mistakes during assembly. It is therefore practically important to introduce design tools that support the development of soft circuits. We developed a web-based graphical user interface, the Soft Compiler, that accepts a user-defined robot behavior as a truth table to generate a mathematically optimized circuit diagram that guides the assembly of a soft fluidic circuit. We describe the design and experimental verification of three soft circuits of increasing complexity, using the Soft Compiler as a design tool and a novel pneumatic glove as an input interface. In one example, we reduce the size of a soft circuit from the original 11 logic gates to 4 logic gates while maintaining circuit functionality. The Soft Compiler is a web-based design tool for fluidic, soft circuits and published under open-source MIT License.

Tapping mode atomic force microscopy has been used to record phase-lag images of patterned self-assembled monolayer (SAM) surfaces in alcohol−water solutions using probe tips functionalized with SAMs that terminate in distinct chemical groups. We find that phase contrast between chemically distinct monolayer regions and adhesion forces are directly correlated: increasing adhesion forces lead to increases in the phase lag. Data recorded in alcohol−water mixtures have been analyzed using a driven oscillator model and show that differences in phase shift between distinct regions of the patterned SAMs can be quantitatively related to differences in the work of adhesion, Wst. Because the adhesion forces are readily interpretable on the basis of surface chemical functionality, our results demonstrate that intermittent contact or tapping mode force microscopy can be used to image samples with chemical sensitivity. The implications and potential applications of this new form of chemical force microscopy are discussed.

The purpose of our technical brief was to first demonstrate that a paradox involving slip reversal exists in a class of sliding contact problems with friction. We were then motivated by the desire to determine a mechanics formulation of these problems which is self-consistent, in which case we do not have to resort to making arguments that depend on the actual dimensions and material properties of a particular situation. We also stated “The finite strain kinematics analysis shows that the paradox disappears when the correct kinematics is used. In this case it is a reasonable engineering solution to use the infinitesimal theory with the assumption that slip is always in the original direction of sliding, because the paradox occurs only in very small regions in which the infinitesimal theory is unrealistic.”We thank the authors of the Discussion for detailing some of the issues with plasticity and rounding as related to traditional engineering materials. The statement is made in the Discussion that a radius of greater than 120 nm is necessary to avoid the paradox. While such a tiny radius may be unrealistic in many applications, it is not at all unusual in, for example, silicon MEMS devices where radii can be nearly atomically sharp as a consequence of an anisotropic etch.The plasticity analysis used in the Discussion assumed a ratio of yield stress to shear modulus of 0.003. However, in rubber and biological materials the “yield” stress can be a significantly higher fraction of the modulus. Even for traditional engineering materials, the elastodynamic problem behaves as the corresponding quasi-static problem with a reduced modulus. As pointed out in the original technical brief, this reduced modulus approaches zero as the speed of the punch approaches the Rayleigh wave speed.For the reasons outlined above we disagree with the statement that “…it is unlikely that the paradox described, though interesting, will have any bearing in a real contact.” We also reiterate that the purpose of our technical brief was to develop a mechanics formulation which is self-consistent.

Background Recent studies have revealed sexually dimorphic associations between the carbamoyl‐phosphate synthase 1 locus, intermediates of the metabolic pathway leading from choline to urea, and ri...

BACKGROUND Pre- and perinatal factors and preschool body size may help identify children developing overweight, but these factors might have changed during the development of the obesity epidemic. OBJECTIVE We aimed to assess the associations between early life risk indicators and overweight at the age of 9 and 15 years at different stages of the obesity epidemic. METHODS We used two population-based Northern Finland Birth Cohorts including 4111 children born in 1966 (NFBC1966) and 5414 children born in 1985-1986 (NFBC1986). In both cohorts, we used the same a priori defined prenatal factors, maternal body mass index (BMI), birth weight, infant weight (age 5 months and 1 year), and preschool BMI (age 2-5 years). We used internal references in early childhood to define percentiles of body size ( 90) and generalized linear models to study the association with overweight, according to the International Obesity Taskforce (IOTF) definitions, at the ages of 9 and 15 years. RESULTS The prevalence of overweight at the age of 15 was 9% for children born in 1966 and 16% for children born in 1986. However, medians of infant weight and preschool BMI changed little between the cohorts, and we found similar associations between maternal BMI, infant weight, preschool BMI, and later overweight in the two cohorts. At 5 years, children above the 90th percentile had approximately a 12 times higher risk of being overweight at the age of 15 years compared to children below the 50th percentile in both cohorts. CONCLUSIONS The associations between early body size and adolescent overweight showed remarkable stability, despite the increase in prevalence of overweight over the 20 years between the cohorts. Using consequently defined internal percentiles may be a valuable tool in clinical practice.