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Aim The aim of this study was to investigate whether prematurity per se or perinatal risk factors explain altered brain structure after preterm birth, in extremely preterm ( EPT) infants without focal brain lesions. Methods A population-based cohort of 58 EPT infants [gestational age ( GA) <27 + 0 weeks] was examined with diffusion magnetic resonance imaging at term-equivalent age and compared with 14 term-born controls. Associations of diffusion measures with prematurity and neonatal risk factors were explored. Data were analysed with tract-based spatial statistics ( TBSS) for whole-brain analysis and region-of-interest ( ROI) analysis. Results Whole-brain analyses showed lower fractional anisotropy ( FA) and higher mean diffusivity ( MD) in several white matter ( WM) tracts in the preterms, which was essentially confirmed by ROI analyses. Within the preterm GA range (23 + 0 to 26 + 6 weeks), GA at birth was not significantly associated with diffusion measures. Bronchopulmonary dysplasia predicted lower FA in the corpus callosum and right inferior longitudinal fasciculus; mechanical ventilation >2 days was predictive of higher MD in the right external capsule. Conclusion White matter microstructure is influenced by preterm birth and by neonatal respiratory factors, whereas the degree of prematurity within the EPT range appears to be of less importance. [ABSTRACT FROM AUTHOR]

The forced transverse vibration of a single-walled carbon nanotube (SWNT) embedded with atomic-size particles was investigated using molecular dynamic simulations. The particles inside the cylindrical cantilever can be trapped near the antinodes or at the vicinity of the SWNT tip. The trapping phenomenon is highly sensitive to the external driving frequencies such that even very small changes in driving frequency can have a strong influence on the probability of the location of the particle inside the SWNT. The trapping effect could potentially be employed to realize the atomic scale control of particle position inside an SWNT via the finite adjustment of the external driving frequency. It may also be suggested that the trapping phenomenon could be utilized to develop high-sensitive mass detectors based on a SWNT resonator. [ABSTRACT FROM AUTHOR]

A novel polymerase chain reaction (PCR) method is presented that utilizes Coriolis and centrifugal effects, produced by rotation of the sample disc, in order to increase internal circulatory rates, and with them temperature homogenization and mixing speeds. A proof of concept has been presented by testing a rapid 45-cycle PCR DNA amplification protocol. During the repeated heating and cooling that constitutes a PCR process, the 100 μL samples were rotated at a speed equivalent to an effective acceleration of gravity of 7,000 g. A cycle time of 20.5 s gave a total process time of 15 min to complete the 45 cycles. A theoretical and numerical analysis of the resulting flow, which describes the increased mixing and temperature homogenization, is presented. The device gives excellent reaction speed efficiency, which is beneficial for rapid PCR. [ABSTRACT FROM AUTHOR]

Organic electrochemical transistors (OECTs) are promising devices for bioelectronics, such as biosensors. However, current cleanroom‐based microfabrication of OECTs hinders fast prototyping and widespread adoption of this technology for low‐volume, low‐cost applications. To address this limitation, a versatile and scalable approach for ultrafast laser microfabrication of OECTs is herein reported, where a femtosecond laser to pattern insulating polymers (such as parylene C or polyimide) is first used, exposing the underlying metal electrodes serving as transistor terminals (source, drain, or gate). After the first patterning step, conducting polymers, such as poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), or semiconducting polymers, are spin‐coated on the device surface. Another femtosecond laser patterning step subsequently defines the active polymer area contributing to the OECT performance by disconnecting the channel and gate from the surrounding spin‐coated film. The effective OECT width can be defined with high resolution (down to 2 µm) in less than a second of exposure. Micropatterning the OECT channel area significantly improved the transistor switching performance in the case of PEDOT:PSS‐based transistors, speeding up the devices by two orders of magnitude. The utility of this OECT manufacturing approach is demonstrated by fabricating complementary logic (inverters) and glucose biosensors, thereby showing its potential to accelerate OECT research. [ABSTRACT FROM AUTHOR]

Main objectives: Executive functions are frequently a weakness in children born preterm. We examined associations of executive functions and general cognitive abilities with brain structure in preterm born adolescents who were born with appropriate weight for gestational age and who have no radiological signs of preterm brain injury on neuroimaging. Methods: The Stockholm Neonatal Project (SNP) is a longitudinal, population-based study of children born preterm (<36 weeks of gestation) with very low birth weight (<1501g) between 1988–1993. At age 18 years (mean 18 years, SD 2 weeks) 134 preterm born and 94 full term participants underwent psychological assessment (general intelligence, executive function measures). Of these, 71 preterm and 63 full term participants underwent Magnetic Resonance Imaging (MRI) at mean 15.2 years (range 12–18 years), including 3D T1-weighted images for volumetric analyses and Diffusion Tensor Imaging (DTI) for assessment of white matter microstructure. Group comparisons of regional grey and white matter volumes and fractional anisotropy (FA, as a measure of white matter microstructure) and, within each group, correlation analyses of cognitive measures with MRI metrics were carried out. Results: Significant differences in grey and white matter regional volumes and widespread differences in FA were seen between the two groups. No significant correlations were found between cognitive measures and brain volumes in any group after correction for multiple comparisons. However, there were significant correlations between FA in projection fibres and long association fibres, linking frontal, temporal, parietal, and occipital lobes, and measures of executive function and general cognitive abilities in the preterm born adolescents, but not in the term born adolescents. Overall significance of the study: In persons born preterm, in the absence of perinatal brain injury on visual inspection of MRI, widespread alterations in regional brain tissue volumes and microstructure are present in adolescence/young adulthood. Importantly, these alterations in WM tracts are correlated with measures of executive function and general cognitive abilities. Our findings suggest that disturbance of neural pathways, rather than changes in regional brain volumes, are involved in the impaired cognitive functions. [ABSTRACT FROM AUTHOR]

Here we show the detection of single gas molecules inside a carbon nanotube based on the change in resonance frequency and amplitude associated with the inertia trapping phenomenon. As its direct implication, a method for controlling the sequence of small molecule is then proposed to realize the concept of manoeuvring of matter atom by atom in one dimension. The detection as well as the implication is demonstrated numerically with the molecular dynamics method. It is theoretically assessed that it is possible for a physical model to be fabricated in the very near future. [ABSTRACT FROM AUTHOR]

Aim: Little is known about the prevalence of discrete white matter abnormalities (WMA) beyond the first years in children born extremely preterm (EPT) and the relation to neurodevelopmental outcomes. Our aim was to investigate the prevalence of discrete WMA in children born EPT and the relationship to neonatal white matter injuries (WMI), white matter (WM) volume, WM diffusivity and neurodevelopment. Methods: The study was a part of a longitudinal follow‐up study of EPT neonates. All children were scanned at Karolinska University hospital 2004–2007 (neonates) and 2014–2015 (children at 8–11 years). WMA was qualitatively assessed by visual inspection. Developmental assessment was conducted at 12 years. Results: In total, 112 children (median age 10.3 years, 56 girls) underwent MRI of the brain (68 EPT, 45 controls). In the EPT group, a subset had MRI around term equivalent age (n = 61). In the EPT group, the prevalence of discrete WMA at 8–11 years was 52%. There was a positive association between WMI at TEA and 8–11 years. There was no association between WMI and WM volumes or diffusivity at 8–11 years. Discrete WMA was not related to neurodevelopmental outcomes. Conclusion: Discrete WMA was prevalent in children born EPT at 8–11 years but were not related to neurodevelopmental outcomes. [ABSTRACT FROM AUTHOR]

Passive particle manipulation using inertial and elasto-inertial microfluidics have received substantial interest in recent years and have found various applications in high throughput particle sorting and separation. For separation applications, elasto-inertial microfluidics has thus far been applied at substantial lower flow rates as compared to inertial microfluidics. In this work, we explore viscoelastic particle focusing and separation in spiral channels at two orders of magnitude higher Reynolds numbers than previously reported. We show that the balance between dominant inertial lift force, dean drag force and elastic force enables stable 3D particle focusing at dynamically high Reynolds numbers. Using a two-turn spiral, we show that particles, initially pinched towards the inner wall using an elasticity enhancer, PEO (polyethylene oxide), as sheath migrate towards the outer wall strictly based on size and can be effectively separated with high precision. As a proof of principle for high resolution particle separation, 15 µm particles were effectively separated from 10 µm particles. A separation efficiency of 98% for the 10 µm and 97% for the 15 µm particles was achieved. Furthermore, we demonstrate sheath-less, high throughput, separation using a novel integrated two-spiral device and achieved a separation efficiency of 89% for the 10 µm and 99% for the 15 µm particles at a sample flow rate of 1 mL/min—a throughput previously only reported for inertial microfluidics. We anticipate the ability to precisely control particles in 3D at extremely high flow rates will open up several applications, including the development of ultra-high throughput microflow cytometers and high-resolution separation of rare cells for point of care diagnostics. [ABSTRACT FROM AUTHOR]

Objective: Magnetic resonance imaging (MRI) of the brain carried out during the neonatal period shows that 55–80% of extremely preterm infants display white matter diffuse excessive high signal intensity (DEHSI). Our aim was to study differences in developmental outcome at the age of 6.5 years in children born extremely preterm with and without DEHSI. Study Design: This was a prospective cohort study of 83 children who were born in Stockholm, Sweden, between 2004 and 2007, born at gestational age of < 27 weeks + 0 days and who underwent an MRI scan of their brain at term equivalent age. The outcome measures at 6.5 years included testing 66 children with the modified Touwen neurology examination, the Movement Assessment Battery for Children 2, the Wechsler Intelligence Scale for Children—Fourth Edition, Beery Visual-motor Integration test—Sixth Edition, and the Strengths and Difficulties Questionnaire. Group-wise comparisons were done between children with and without DEHSI using Student t-test, Mann Whitney U test, Chi square test and regression analysis. Results: DEHSI was detected in 39 (59%) of the 66 children who were assessed at 6.5 years. The presence of DEHSI was not associated with mild neurological dysfunction, scores on M-ABC assessment, cognition, visual-motor integration, or behavior at 6.5 years. Conclusion: The presence of qualitatively defined DEHSI on neonatal MRI did not prove to be a useful predictor of long-term impairment in children born extremely preterm. [ABSTRACT FROM AUTHOR]