Design and evaluation of a microcantilever aptasensor

Aptamers enhance flexibility in biosensor design. An aptasensor employs aptamers as a biological recognition element for biosensing. This paper presents design, fabrication, and evaluation of a microcantilever aptasensor. To identify and avoid potential bottlenecks in the aptasensor design, the parameters of the aptasensor are investigated through modelling and simulation. Next, thin SU-8 microcantilevers are fabricated to form the aptasensor. Characterization of the fabricated aptasensor is presented. Next, a plasma-based surface funtionalisation method is used to immobilize aptamers on the atasensor. Finally, an evaluation of the performance of the aptasensor is performed through detection of thrombin molecules. The evaluation results are presented and discussed. © 2014 IEEE.

Interfacial adhesion in natural fiber-reinforced polymer composites

Concerns about the environment and increasing awareness about sustainability issues are driving the push for developing new materials that incorporate renewable sustainable resources. Th is has resulted in the use of natural fi bers for developing natural fi ber-reinforced polymer composites (NFRPCs). A fundamental understanding of the fi ber-fi ber and fi ber-matrix interface is critical to the design and manufacture of polymer composite materials because stress transfer between load-bearing fi bers can occur at the both of these interfaces. Effi cient stress transfer from the matrix to the fi ber will result in polymer composites exhibiting suitable mechanical and thermal performance. Th e development of new techniques has facilitated a better understanding of the governing forces that occur at the interface between matrix and natural fi ber. Th e use of surfacemodification is seen as a critical processing parameter for developing new materials, and plasma-based modifi cation techniques are gaining more prominence from an environmental point of view, as well as a practical approach.

Feed intake, growth, plasma glucose and urea nitrogen concentration, and cacass traits of lambs fed isoenergetic amounts of canola meal, soybean meal, and fish meal with forage based diet.

This experiment was conducted to examine the effect of feeding small, isoenergetic amounts of supplements containing high protein and functional lipid components, rather than the greater amounts of cereal and/or legume grains usually fed during the dry season in Australia, on dry matter intake (DMI), growth performance, plasma metabolites, and fat deposition in lambs consuming low quality roughage. Thirty two crossbred wether lambs ([Merino × Border Leicester] × Poll Dorset) were divided into four groups by stratified randomization according to liveweight (26–33 kg). After a 7-day adaptation to a hay diet (lucerne hay:oaten hay; 30:70), lambs were allocated to four treatments consisting of (1) basal diet of lucerne hay:oat hay (20:80; metabolizable energy (ME) = 7.0 MJ/kg DM), Basal; (2) basal + canola meal (84 g per day), CM; (3) basal + soymeal (75 g per day), SM; or (4) basal + fishmeal (80 g per day), FM. Daily hay and supplement DMI, and weekly liveweight were recorded during a 53-day experimental study. Blood samples were taken on day 1 and pre- and post-feeding on days 30 and 53 to measure changes in plasma glucose and plasma urea nitrogen (PUN) concentration. At the end of the experiment, lambs were slaughtered and hot carcass weight (HCW) recorded; cold carcass fatness (total muscle and adipose tissue depth at 12th rib, 110 mm from midline; GR) was determined at 24 h postmortem. Total DMI was increased (P < 0.001) in CM, SM and FM treatments, but basal hay DMI intake was only increased (P < 0.01) in CM and FM treatments compared with Basal treatment. This resulted in significant (P < 0.01) increases in metabolizable energy (ME) and crude protein (CP) intakes in all supplemented treatments, with the highest intakes recorded in the FM treatment. Liveweight gain (LWG) was significantly increased in CM and SM (P < 0.05) and FM (P < 0.01) treatments but HCW was significantly (P < 0.01) heavier slaughter only in the FM treatment. Feed conversion efficiency (P < 0.001) and GR fat at depth (P < 0.05) was reduced in all supplement treatments compared with Basal. Plasma glucose concentration was significantly (P < 0.05) increased after feeding in all treatments but there was no treatment effect. PUN was significantly increased over time in the supplemented treatments compared with the Basal treatment; there was no significant difference between supplement treatments by day 53. Results show that feeding small amounts of high protein and lipid-containing supplements improves production responses and are beneficial in producing carcasses with more lean compared with carcasses from lambs fed a low quality hay diet.

Arterial compliance, blood pressure, plasma leptin, and plasma lipids in women are improved with weight reduction equally with a meat-based diet and a plant-based diet

Obesity, strongly associated with the risk for coronary heart disease (CHD), is becoming increasingly prevalent. This study was designed to establish first whether systemic arterial compliance (SAC), an index of arterial function, is improved with weight loss and second, whether cardiovascular risk factors that improve with weight loss are reduced equally with lean meat or with an equivalent amount of plant protein in the diet. Thirty-six women, mostly overweight or obess, aged 40 ± 9 years, were allocated nonrandomly to a 16-week parallel-design trial of two equienergetic diets designed to lead to weight loss, with one arm of the study emphasizing red meat and the other soybeans as the major protein source. Body weight, waist and hip circumference, and plasma lipids, glucose, insulin, and leptin levels were measured, and SAC was calculated from ultrasound measurement of aortic flow velocity and aortic root driving pressure. Subjects lost weight (9% of body weight in 16 weeks) and showed decreased plasma total and low-density lipoprotein (LDL) cholesterol (12% and 14%, P < .0001, respectively), triacylglycerol (17%, P < .05), and leptin (24%, P < .01) concentrations. However, lipoprotein(a) [Lp(a)] levels did not change significantly. Mean arterial pressure (MAP) decreased 7% and SAC increased 28% (P < .001 for both). However, only the decrease in arterial pressure correlated significantly with the reduction in the waist to hip ratio (WHR), and the improvement in SAC correlated inversely with the blood pressure reduction (P < .001 for both). Further, weight loss and the metabolic benefits of weight loss occurred equally with the meat-based and plant-based diets. We conclude that moderate weight loss in women leads to a substantial reduction in the cardiovascular risk, including SAC.

Assessment of three levels of folic acid on serum folate and plasma homocysteine: a randomised placebo-controlled double-blind dietary intervention trial.

Objective: To determine the minimum effective dose of folic acid required to appreciably increase serum folate and to produce a significant reduction in plasma total homocysteine (tHcy).

Design: Double-blind, randomised placebo-controlled intervention trial.

Setting: Community-based project in a New Zealand city.

Subjects: Seventy free living men and women with tHcy10 µmol/l. Mean age (range) was 58 (29-90) y.

Interventions: Daily consumption over 4 weeks of 20 g breakfast cereal either unfortified (placebo) or fortified with 100, 200 or 300 µg folic acid. Dietary intake was determined by weighed diet records and consumption of commercially fortified products was avoided.

Main outcome measures: Plasma tHcy and serum folate concentrations.

Results: Average serum folate concentrations (95% CI) increased significantly in the treatment groups relative to the control group by 28(9-51)%, 60(37-87)% and 79(51-114)% for supplementation with 100, 200 and 300 µg folic acid, respectively. A reduction in tHcy was observed, being 16(8-22)%, 12(4-18)% and 17(9-24)% in the three treatment groups, respectively.

Conclusions: A regular intake of as little as 100 µg folic acid per day was sufficient to lower tHcy in persons at the upper end of the normal range for tHcy. Low-level fortification may also be appropriate for lowering the risk of neural tube defects given that, when aggregated from all sources, the total intake of folic acid may be sufficiently high to adequately improve the folate status of young women.

Association of television viewing with fasting and 2-h postchallenge plasma glucose levels in adults without diagnosed diabetes

OBJECTIVE—We examined the associations of television viewing time with fasting plasma glucose (FPG) and 2-h postchallenge plasma glucose (2-h PG) levels in Australian adults.

RESEARCH DESIGN AND METHODS—A total of 8,357 adults aged >35 years who were free from diagnosed diabetes and who attended a population-based cross-sectional study (Australian Diabetes, Obesity and Lifestyle Study [AusDiab]) were evaluated. Measures of FPG and 2-h PG were obtained from an oral glucose tolerance test. Self-reported television viewing time (in the previous week) was assessed using an interviewer-administered questionnaire. Homeostasis model assessment (HOMA) of insulin sensitivity (HOMA-%S) and ß-cell function (HOMA-%B) were calculated based on fasting glucose and insulin concentrations.

RESULTS—After adjustment for confounders and physical activity time, time spent watching television in women was positively associated with 2-h PG, log fasting insulin, and log HOMA-%B and inversely associated with log HOMA-%S (P < 0.05) but not with FPG. No significant associations were observed with glycemic measures in men. The ß-coefficients across categories of average hours spent watching television per day (<1.0, 1.0–1.9, 2.0–2.9, 3.0–3.9, and ≥4.0) for 2-h PG in women were 0 (reference), 0.009, 0.047, 0.473, and 0.501, respectively (P for trend = 0.02).

CONCLUSIONS—Our findings highlight the unique deleterious relationship of sedentary behavior (indicated by television viewing time) and glycemic measures independent of physical activity time and adiposity status. These relationships differed according to sex and type of glucose measurement, with the 2-h PG measure being more strongly associated with television viewing. The findings suggest an important role for reducing sedentary behavior in the prevention of type 2 diabetes and cardiovascular disease, especially in women.

Age-related changes in ovarian characteristices, plasma sex steroids and fertility during pubertal development in captive female Murray cod Maccullochella peelii peelii

Age-related changes in ovarian development characteristics and plasma sex steroids in female Murray cod were examined throughout their second, third and fourth years of life to better understand the physiological and endocrine processes associated with puberty in this species in captivity. Spawning performance of 2+ and 3+ year old females was also assessed to identify ontogenetic differences in egg fertility. Puberty was acquired in 38% of 1+ year old females and 100% of age 2+ females. By age 3+, all females had developed full (adult) reproductive function. Ovarian development in pubertal fish was characterised by a rapid transition between cortical alveoli and lipid droplet oogenic phases, coinciding with significantly lower plasma 17β-oestradiol in age 2+ females (p < 0.05). Mean mature oocyte diameter (2.44 mm), post-fertilisation viability (30.80%) and hatchability (0.99%) of eggs from age 2+ females were significantly reduced relative to age 3+ adults (2.81 mm, 84.89% and 23.58%, respectively). Ovaries of pubertal Murray cod exhibited both vitellogenic and ovulatory capacities, yet functional abnormalities during secondary oocyte growth are likely to have contributed to poor egg fertility and consequently, evaluations of age-at-first maturity based on the presence of advanced ovarian stages may overestimate the reproductive potential of younger broodstock populations.

Effect of a low-resource-intensive lifestyle modification program incorporating gymnasium-based and home-based resistance training on type 2 diabetes risk in Australian adults

OBJECTIVE--The purpose of this study was to assess the effectiveness of a low-resource-intensive lifestyle modification program incorporating resistance training and to compare a gymnasium-based with a home-based resistance training program on diabetes diagnosis status and risk.

RESEARCH DESIGN AND METHODS--A quasi-experimental two-group study was undertaken with 122 participants with diabetes risk factors; 36.9% had impaired glucose tolerance (1GT) or impaired fasting glucose (IFG) at baseline. The intervention included a 6-week group self-management education program, a gymnasium-based or home-based 12-week resistance training program, and a 34-week maintenance program. Fasting plasma glucose (FPG) and 2-h plasma glucose, blood lipids, blood pressure, body composition, physical activity, and diet were assessed at baseline and week 52.

RESULTS--Mean 2-h plasma glucose and FPG fell by 0.34 mmol/1 (95% CI--0.60 to--0.08) and 0.15 mmol/l (-0.23 to -0.07), respectively. The proportion of participants with IFG or IGT decreased from 36.9 to 23.0% (P = 0.006). Mean weight loss was 4.07 kg (-4.99 to -3.15). The only significant difference between resistance training groups was a greater reduction in systolic blood pressure for the gymnasium-based group (P = 0.008).

CONCLUSIONS--This intervention significantly improved diabetes diagnostic status and reduced diabetes risk to a degree comparable to that of other low-resource-intensive lifestyle modification programs and more intensive interventions applied to individuals with IGT. The effects of home-based and gymnasium-based resistance training did not differ significantly.

Single-point isotope measurements in blood cells and plasma to estimate the time since diet switches

1. Understanding ecological phenomena often requires an accurate assessment of the timing of events. To estimate the time since a diet shift in animals without knowledge on the isotope ratios of either the old or the new diet, isotope ratio measurements in two different tissues (e.g. blood plasma and blood cells) at a single point in time can be used. For this ‘isotopic-clock’ principle, we present here a mathematical model that yields an analytical and easily calculated outcome.

2. Compared with a previously published model, our model assumes the isotopic difference between the old and new diets to be constant if multiple measurements are taken on the same subject at different points in time. Furthermore, to estimate the time since diet switch, no knowledge of the isotopic signature of tissues under the old diet, but only under the new diet is required.

3. The two models are compared using three calibration data sets including a novel one based on a diet shift experiment in a shorebird (red knot Calidris canutus); sensitivity analyses were conducted. The two models behaved differently and each may prove rather unsatisfactory depending on the system under investigation. A single-tissue model, requiring knowledge of both the old and new diets, generally behaved quite reliably.

4. As blood (cells) and plasma are particularly useful tissues for isotopic-clock research, we trawled the literature on turnover rates in whole blood, cells and plasma. Unfortunately, turnover rate predictions using allometric relations are too unreliable to be used directly in isotopic-clock calculations.

5. We advocate that before applying the isotopic-clock methodology, the propagation of error in the ‘time-since-diet-shift’ estimation is carefully assessed for the system under scrutiny using a sensitivity analysis as proposed here.

Association between hyperglycaemia and fracture risk in non-diabetic middle-aged and older Australians : a national, population-based prospective study (AusDiab)

Summary : The association between pre-diabetes and fracture risk remains unclear. In this large cohort of middle-aged and older Australian men and women without diabetes, elevated 2-h plasma glucose and pre-diabetes were associated with a reduced 5-year risk of low trauma and all fractures in women, independently of BMI, fasting insulin and other lifestyle factors.

Introduction : We aimed to (1) examine associations between fasting and 2-h plasma glucose (FPG and 2-h PG), fasting insulin and risk of low trauma and all fractures in non-diabetic adults and (2) compare fracture risk between adults with pre-diabetes (impaired glucose tolerance or impaired fasting glucose) and those with normal glucose tolerance (NGT).

Methods : Six thousand two hundred fifty-five non-diabetic men and women aged ≥40 years with NGT (n = 4,855) and pre-diabetes (n = 1,400) were followed for 5 years in the AusDiab Study. Fractures were self-reported.

Results : Five hundred thirty-nine participants suffered at least one fracture (368 women, 171 men), of which the majority (318) occurred after a low-energy trauma (258 women, 60 men). In women, a 2-h PG ≥7.2 mmol/L (highest quartile) was associated with a decreased risk of low trauma and all fractures independent of age and BMI [OR (95% CI) for low trauma fractures, 0.59 (0.40–0.88)], but also fasting insulin, smoking, physical activity, history of fracture, dietary calcium and alcohol intake or menopausal status. There was no effect of 2-h PG on fracture risk in men [OR (95% CI), 1.39 (0.60–3.26)] or any relationship between fracture risk and quartiles of FPG or insulin in either sex. Compared to women with NGT, those with pre-diabetes had a reduced risk of fracture [OR (95% CI) for all fractures, 0.70 (0.52–0.95); for low trauma fractures, 0.75 (0.53–1.05)].

Conclusion : Elevated 2-h PG levels and pre-diabetes were inversely associated with low trauma and/or all fractures in non-diabetic women, independent of BMI and fasting insulin levels.

Lifestyle factors fail to explain the variation in plasma leptin concentrations in women

To assess the relationship between circulating leptin concentrations, metabolic parameters, and lifestyle factors such as alcohol intake, physical activity level, smoking habits, and reproductive history, a cohort of 359 women was drawn from a population-based study conducted in Victoria, Australia. The parameters measured included body mass index (BMI); waist and hip circumference; blood pressure; and fasting glucose, insulin, triacylglycerol, cholesterol, and leptin concentrations. In addition, a self-administered questionnaire was used to assess reproductive history, physical activity level, alcohol intake, and smoking habits. Our results demonstrated that BMI, body weight, waist circumference, and hip circumference were all strongly correlated with circulating leptin concentrations in this population (r > 0.56, P < 0.001 in all cases). Waist/hip ratio, triacylglycerols, insulin, glucose, and cholesterol were also associated with leptin (P < 0.05), but there was no association between leptin and age, height, or blood pressure. When these associations were adjusted for BMI, age, glucose, and waist circumference were significantly associated with leptin. The lifestyle factors examined did not help to explain the observed variation in leptin concentrations between individuals when results were adjusted for degree of adiposity and age.

Serum 25-Hydroxyvitamin D, calcium intake and risk of type 2 diabetes after 5 years : results from a national, population-based prospective study (the Australian Diabetes, Obesity and Lifestyle study)

OBJECTIVE To examine whether serum 25-hydroxyvitamin D (25OHD) and dietary calcium predict incident type 2 diabetes and insulin sensitivity.

RESEARCH DESIGN AND METHODS A total of 6,537 of the 11,247 adults evaluated in 1999–2000 in the Australian Diabetes, Obesity and Lifestyle (AusDiab) study, returned for oral glucose tolerance test (OGTT) in 2004–2005. We studied those without diabetes who had complete data at baseline (n = 5,200; mean age 51 years; 55% were women; 92% were Europids). Serum 25OHD and energy-adjusted calcium intake (food frequency questionnaire) were assessed at baseline. Logistic regression was used to evaluate associations between serum 25OHD and dietary calcium on 5-year incidence of diabetes (diagnosed by OGTT) and insulin sensitivity (homeostasis model assessment of insulin sensitivity [HOMA-S]), adjusted for multiple potential confounders, including fasting plasma glucose (FPG).

RESULTS During the 5-year follow-up, 199 incident cases of diabetes were diagnosed. Those who developed diabetes had lower serum 25OHD (mean 58 vs. 65 nmol/L; P < 0.001) and calcium intake (mean 881 vs. 923 mg/day; P = 0.03) compared with those who remained free of diabetes. Each 25 nmol/L increment in serum 25OHD was associated with a 24% reduced risk of diabetes (odds ratio 0.76 [95% CI 0.63–0.92]) after adjusting for age, waist circumference, ethnicity, season, latitude, smoking, physical activity, family history of diabetes, dietary magnesium, hypertension, serum triglycerides, and FPG. Dietary calcium intake was not associated with reduced diabetes risk. Only serum 25OHD was positively and independently associated with HOMA-S at 5 years.

CONCLUSIONS Higher serum 25OHD levels, but not higher dietary calcium, were associated with a significantly reduced risk of diabetes in Australian adult men and women.

Influence of atmospheric helium plasma on the surface energy of jute fibres and the performance of resulting composites

In this work, an atmospheric pressure glow discharge helium plasma treatment was employed to modify the surface properties of jute fibres. The resulting bio-composites showed an increase in flexural properties and interlaminar shear strength (ILSS) compared to composites produced using untreated jute fibres. To understand the reason behind the ILSS improvement, the acid–base properties of jute fibres were determined by contact angle analysis using the capillary rise method. The results were fitted further to van Oss–Chaudhury–Good (vOCG) and Chang–Qin–Chen (CQC) models to determine the Lifshitz–van der Waals (LW) and acid–base components of surface energy. Surface energy determined by the vOCG model revealed that plasma treatment of jute fibre resulted in a 22% increase in total surface energy, a 19% increase in the LW component and a 24% increase in the acid–base component of surface energy. The increase in the acid–base component is due to the significant increase (69%) in the electron-accepting (γ+S) parameter. On the other hand, the CQC model clearly indicates an amphoteric nature of the fibre surface based on opposite signs of the acid and base principal values (PSa and PSb). Overall, the results indicated that increases in both LW and acid–base components were responsible for improvement in the properties of the composites.

Low serum 25-hydroxyvitamin D is associated with increased risk of the development of the metabolic syndrome at five years : results from a national, population-based prospective study (the Australian Diabetes, Obesity and Lifestyle Study : AusDiab)

Context: Serum 25-hydroxyvitamin D [25(OH)D] concentration has been inversely associated with the prevalence of metabolic syndrome (MetS), but the relationship between 25(OH)D and incident MetS remains unclear.

Objective: We evaluated the prospective association between 25(OH)D, MetS, and its components in a large population-based cohort of adults aged 25 yr or older.

Design: We used baseline (1999–2000) and 5-yr follow-up data of the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab).

Participants: Of the 11,247 adults evaluated at baseline, 6,537 returned for follow-up. We studied those without MetS at baseline and with complete data (n = 4164; mean age 50 yr; 58% women; 92% Europids).

Outcome Measures: We report the associations between baseline 25(OH)D and 5-yr MetS incidence and its components, adjusted for age, sex, ethnicity, season, latitude, smoking, family history of type 2 diabetes, physical activity, education, kidney function, waist circumference (WC), and baseline MetS components.

Results: A total of 528 incident cases (12.7%) of MetS developed over 5 yr. Compared with those in the highest quintile of 25(OH)D (≥34 ng/ml), MetS risk was significantly higher in people with 25(OH)D in the first (<18 ng/ml) and second (18–23 ng/ml) quintiles; odds ratio (95% confidence interval) = 1.41 (1.02–1.95) and 1.74 (1.28–2.37), respectively. Serum 25(OH)D was inversely associated with 5-yr WC (P < 0.001), triglycerides (P < 0.01), fasting glucose (P < 0.01), and homeostasis model assessment for insulin resistance (P < 0.001) but not with 2-h plasma glucose (P = 0.29), high-density lipoprotein cholesterol (P = 0.70), or blood pressure (P = 0.46).

Conclusions: In Australian adults, lower 25(OH)D concentrations were associated with increased MetS risk and higher WC, serum triglyceride, fasting glucose, and insulin resistance at 5 yr. Vitamin D supplementation studies are required to establish whether the link between vitamin D deficiency and MetS is causal.

Malondialdehyde plasma concentration correlates with declarative and working memory in patients with recurrent depressive disorder

Oxidative stress has been implicated in the cognitive decline, especially in memory impairment. The purpose of this study was to determine the concentration of malondialdehyde (MDA) in patients with recurrent depressive disorders (rDD) and to define relationship between plasma levels of MDA and the cognitive performance. The study comprised 46 patients meeting criteria for rDD. Cognitive function assessment was based on: The Trail Making Test , The Stroop Test, Verbal Fluency Test and Auditory-Verbal Learning Test. The severity of depression symptoms was assessed using the Hamilton Depression Rating Scale (HDRS). Statistically significant differences were found in the intensity of depression symptoms, measured by the HDRS on therapy onset versus the examination results after 8 weeks of treatment (P < 0.001). Considering the 8-week pharmacotherapy period, rDD patients presented better outcomes in cognitive function tests. There was no statistically significant correlation between plasma MDA levels, and the age, disease duration, number of previous depressive episodes and the results in HDRS applied on admission and on discharge. Elevated levels of MDA adversely affected the efficiency of visual-spatial and auditory-verbal working memory, short-term declarative memory and the delayed recall declarative memory. 1. Higher concentration of plasma MDA in rDD patients is associated with the severity of depressive symptoms, both at the beginning of antidepressants pharmacotherapy, and after 8 weeks of its duration. 2. Elevated levels of plasma MDA are related to the impairment of visual-spatial and auditory-verbal working memory and short-term and delayed declarative memory.