Publications

Dislocation theory is used to invoke a strain gradient theory of rate independent plasticity. Hardening is assumed to result from the accumulation of both randomly stored and geometrically necessary dislocation. The density of the geometrically necessary dislocations scales with the gradient of plastic strain. A deformation theory of plasticity is introduced to represent in a phenomenological manner the relative roles of strain hardening and strain gradient hardening. The theory is a non-linear generalization of Cosserat couple stress theory. Tension and torsion experiments on thin copper wires confirm the presence of strain gradient hardening. The experiments are interpreted in the light of the new theory.

Magnesium-doped gallium nitride nanowires have been synthesized via metal-catalyzed chemical vapor deposition. Nanowires prepared on c-plane sapphire substrates were found to grow normal to the substrate, and transmission electron microscopy studies demonstrated that the nanowires had single-crystal structures with a 〈0001〉 growth axis that is consistent with substrate epitaxy. Individual magnesium-doped gallium nitride nanowires configured as field-effect transistors exhibited systematic variations in two-terminal resistance as a function of magnesium dopant incorporation, and gate-dependent conductance measurements demonstrated that optimally doped nanowires were p-type with hole mobilities of ca. 12 cm2/V·s. In addition, transport studies of crossed gallium nitride nanowire structures assembled from p- and n-type materials show that these junctions correspond to well-defined p−n diodes. In forward bias, the p−n crossed nanowire junctions also function as nanoscale UV-blue light emitting diodes. The new synthesis of p-type gallium nitride nanowire building blocks opens up significant potential for the assembly of nanoscale electronics and photonics.

'Photoetching' published in 'Encyclopedia of Nanotechnology'

Problem: To assess the association between antibodies to Chlamydia trachomatis heat shock proteins 60 and 10 (Hsp60 and Hsp10) and subfertility in a general population sample. Method of Study: A nested case ( n = 146)–control ( n = 278) study in a population‐based birth cohort. Serum immunoglobulin (Ig)G and IgA antibodies against C. trachomatis Hsp60 and Hsp10, explanatory factors, were measured by enzyme immunoassay, using recombinant proteins as antigens. The main outcome variable was subfertility (time to pregnancy ≥12 months). Results: The prevalence and medians of serum IgA antibodies to Hsp60 and Hsp10 were significantly higher in the female partners of subfertile couple than in their fertile controls. On the contrary, among male partners of subfertile couple, especially among smokers serum antibody levels to Hsp antigens were lower than in the controls. Conclusion: The results indicate a serological association of antibodies to chlamydial Hsp antigens with female subfertility in a population‐based sample.

Adipose tissue inflammation is an important pathological process in obese people, associated with diabetes and cardiovascular disease. We hypothesized that 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] inhibits cytokine secretion from adipocytes via direct inhibition of transcription factor nuclear factor-κB (NF-κB). We utilized two different human models. Bone marrow-derived human mesenchymal stromal cells (hMSCs) differentiated into adipocytes, and adipocytes isolated from biopsies stimulated with lipopolysaccharide (LPS) were treated with or without 1,25(OH)2D3. Expression and secretion of interleukin-6 (IL-6) were measured by quantitative RT-PCR analysis and ELISA. Assessment of NF-κB nuclear translocation, DNA binding activity was performed by immunofluorescence (IF) and electrophoretic mobility assay (EMSA). Inhibitor κB (IκB) and its phosphorylation were detected by Western blot (WB) analysis. Simultaneous 1,25(OH)2D3 cotreatment significantly reduced LPS-stimulated (10 ng/ml) IL-6 secretion dose dependently by 15% at 10–10 M and 26% at 10–7 M (P<0.05) in hMSCs, while preincubation with 1,25(OH)2D3 (10–7 M) for 24 h reduced IL-6 secretion by 24 and 35% (P<0.001) and mRNA levels by 34 and 30% (P<0.05) in hMSCs and isolated adipocytes, respectively. 1,25(OH)2D3 suppressed LPS-stimulated IκB phosphorylation-mediated NF-κB translocation into the nucleus were evident from WB, IF, and EMSA. 1,25(OH)2D3 inhibits LPS-stimulated IL-6 secretion in two human adipocyte models via interference with NF-κB signaling.—Mutt, S. J., Karhu, T., Lehtonen, S., Lehenkari, P., Carlberg, C., Saarnio, J., Sebert, S., Hyppönen, E., Järvelin, M.-R., Herzig, K.-H. Inhibition of cytokine secretion from adipocytes by 1,25-dihydroxyvitamin D3 via the NF-κB pathway. FASEB J. 26, 4400–4407 (2012). www.fasebj.org

The 31 papers in this special issue focus on nanowire transistors and cover the modeling, device design and technology of these transistors. Other papers on the same topic are appearing in a special issue of the IEEE Transactions on Nanotechnology.

Abstract Background/Objectives Maternal pre-pregnancy overweight/obesity and gestational diabetes (GDM) are associated with increased fat deposition in adult offspring. The purpose of this study was to identify if maternal pre-pregnancy overweight (body mass index (BMI) ≥ 25 kg/m 2 ) or GDM are associated with dietary quality or intake in adult offspring. Subjects/Methods Participants ( n = 882) from two longitudinal cohort studies (ESTER Maternal Pregnancy Disorders Study and the Arvo Ylppö Longitudinal Study) completed a validated food-frequency questionnaire at a mean age of 24.2 years (SD 1.3). Diet quality was evaluated by a Recommended Finnish Diet Index (RDI). The study sample included offspring of normoglycaemic mothers with pre-pregnancy overweight/obesity (ONO = 155), offspring of mothers with GDM regardless of BMI (OGDM = 190) and offspring of mothers with normal weight and no GDM (controls; n = 537). Results Among men, daily energy and macronutrient intakes were similar in ONO and controls. However, after adjusting for current offspring characteristics, including BMI, daily carbohydrate intake relative to total energy intake was higher in ONO-men [2.2 percentages of total energy intake (95% confidence interval 0.4, 4.0)]. In ONO-women, macronutrient intakes relative to total energy intake were similar with controls, while total daily energy intake seemed lower [−587.2 kJ/day (−1192.0, 4.4)]. After adjusting for confounders, this difference was attenuated. Adherence to a healthy diet, as measured by RDI, was similar in ONO and controls [mean difference: men 0.40 (−0.38, 1.18); women 0.25 (−0.50, 1.00)]. In OGDM vs. controls, total energy and macronutrient intakes were similar for both men and women. Also adherence to a healthy diet was similar [RDI: men 0.09 (−0.62, 0.80); women −0.17 (−0.93, 0.59)]. Conclusions Our study suggested higher daily carbohydrate intake in male offspring exposed to maternal pre-pregnancy overweight/obesity, compared with controls. Prenatal exposure to GDM was not associated with adult offspring dietary intakes.

OBJECTIVE—To evaluate the role of non-HDL cholesterol and apolipoprotein (apo)B, markers of all potentially atherogenic lipoproteins, as predictors of cardiovascular disease (CVD) in comparison with LDL cholesterol in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS—We prospectively followed 746 diabetic men in the Health Professionals’ Follow-up Study who were aged 46–81 years and free of CVD or cancer at the time of blood draw in 1993–1994. During 6 years of follow-up, we ascertained 103 incident CVD cases. RESULTS—We used Cox proportional hazard modeling to estimate the relative risk (RR) of CVD. After adjustment for age, BMI, and other lifestyle risk factors, the multivariate RR of CVD (the highest versus the lowest quartile) was 2.34 (95% CI 1.26–4.32) for non-HDL cholesterol, 2.31 (1.23–4.35) for apoB, and 1.74 (0.99–3.06) for LDL cholesterol. Comparisons of nested models indicate that non-HDL cholesterol, but not apoB, adds significantly to the prediction of CVD risk beyond LDL cholesterol. The area under the receiver operating characteristic curve was 0.685, 0.691, 0.695, and 0.722 for the CVD risk-prediction model with LDL cholesterol, apoB, non-HDL cholesterol, and total cholesterol–to–HDL cholesterol ratio (or the non-HDL–to–HDL cholesterol ratio), respectively. CONCLUSIONS—Non-HDL cholesterol and apoB are more potent predictors of CVD incidence among diabetic men than LDL cholesterol. Statistically, the ratio of total to HDL cholesterol is the best predictor of CVD in this cohort of diabetic men.

While both the 2012 and 2014 Consumer Reports concerned arsenic levels in US rice, no previous study has evaluated long-term consumption of total rice, white rice and brown rice in relation to risk of developing cancers. We investigated this in the female Nurses' Health Study (1984-2010), and Nurses' Health Study II (1989-2009), and the male Health Professionals Follow-up Study (1986-2008), which included a total of 45,231 men and 160,408 women, free of cancer at baseline. Validated food frequency questionnaires were used to measure rice consumption at baseline and repeated almost every 4 years thereafter. We employed Cox proportional hazards regression model to estimate multivariable relative risks (RRs) and 95% confidence intervals (95% CIs). During up to 26 years of follow-up, we documented 31,655 incident cancer cases (10,833 in men and 20,822 in women). Age-adjusted results were similar to multivariable-adjusted results. Compared to participants with less than one serving per week, the multivariable RRs of overall cancer for individuals who ate at least five servings per week were 0.97 for total rice (95% CI: 0.85-1.07), 0.87 for white rice (95% CI: 0.75-1.01), and 1.17 for brown rice (95% CI: 0.90-1.26). Similar non-significant associations were observed for specific sites of cancers including prostate, breast, colon and rectum, melanoma, bladder, kidney, and lung. Additionally, the null associations were observed among European Americans and non-smokers, and were not modified by BMI. Long-term consumption of total rice, white rice or brown rice was not associated with risk of developing cancer in US men and women.

This paper describes physical-organic studies of charge transport by tunneling through self-assembled monolayers (SAMs), based on systematic variations of the structure of the molecules constituting the SAM. Replacing a −CH2CH2– group with a −CONH– group changes the dipole moment and polarizability of a portion of the molecule and has, in principle, the potential to change the rate of charge transport through the SAM. In practice, this substitution produces no significant change in the rate of charge transport across junctions of the structure AgTS-S(CH2)mX(CH2)nH//Ga2O3/EGaIn (TS = template stripped, X = −CH2CH2– or −CONH–, and EGaIn = eutectic alloy of gallium and indium). Incorporation of the amide group does, however, increase the yields of working (non-shorting) junctions (when compared to n-alkanethiolates of the same length). These results suggest that synthetic schemes that combine a thiol group on one end of a molecule with a group, R, to be tested, on the other (e.g., HS∼CONH∼R) using an amide-based coupling provide practical routes to molecules useful in studies of molecular electronics.

The purpose of this review was to examine the literature assessing the relationship between prenatal exposure to nicotine, alcohol, caffeine, and psychosocial stress during pregnancy to the risk of developing behavioral problems related to attention deficit hyperactivity disorder (ADHD) in childhood.PubMed, MEDLINE, EMBASE, and PsycINFO were searched systematically. Studies using DSM diagnostic criteria and other validated diagnostic or screening instruments for ADHD and those examining ADHD symptoms were included. A narrative approach was used because the studies differed too much in methods and data sources to permit a quantitative meta-analysis.Twenty-four studies on nicotine (tobacco smoking), nine on alcohol, one on caffeine, and five on psychosocial stress were identified. All were published between 1973 and 2002. In spite of inconsistencies, the studies on nicotine indicated a greater risk of ADHD-related disorders among children whose mothers smoked during pregnancy. Contradictory findings were reported in the alcohol studies, and no conclusion could be reached on the basis of the caffeine study. Results from studies on psychological stress during pregnancy were inconsistent but indicated a possible modest contribution to ADHD symptoms in the offspring. Many studies suffered from methodological shortcomings, such as recall bias, crude or inaccurate exposure assessments, low statistical power, and lack of or insufficient control of confounders. A general lack of information on familial psychopathology also limited the interpretations.Exposure to tobacco smoke in utero is suspected to be associated with ADHD and ADHD symptoms in children. Other maternal lifestyle factors during pregnancy may also be associated with these disorders. Further studies are needed to reach conclusions.