Supramolecular Peptoid Structure Strengthens Complexation with Polyacrylic Acid Microgels.

We have studied the complexation between cationic antimicrobials and polyanionic microgels to create self-defensive surfaces that responsively resist bacterial colonization. An essential property is the stable sequestration of the loaded (complexed) antimicrobial within the microgel under a physiological ionic strength. Here, we assess the complexation strength between poly(acrylic acid) [PAA] microgels and a series of cationic peptoids that display supramolecular structures ranging from an oligomeric monomer to a tetramer. We follow changes in loaded microgel diameter with increasing [Na+] as a measure of the counterion doping level. Consistent with prior findings on colistin/PAA complexation, we find that a monomeric peptoid is fully released at ionic strengths well below physiological conditions, despite its +5 charge. In contrast, progressively higher degrees of peptoid supramolecular structure display progressively greater resistance to salting out, which we attribute to the greater entropic stability associated with the complexation of multimeric peptoid bundles.

Assessment of Early Diastolic Intraventricular Pressure Difference in Children by Blood Speckle-Tracking Echocardiography.

BACKGROUND: The lack of reliable echocardiographic techniques to assess diastolic function in children is a major clinical limitation. Our aim was to develop and validate the intraventricular pressure difference (IVPD) calculation using blood speckle-tracking (BST) and investigate the method's potential role in the assessment of diastolic function in children. METHODS: Blood speckle-tracking allows two-dimensional angle-independent blood flow velocity estimation. Blood speckle-tracking images of left ventricular (LV) inflow from the apical 4-chamber view in 138 controls, 10 patients with dilated cardiomyopathies (DCMs), and 21 patients with hypertrophic cardiomyopathies (HCMs) <18 years of age were analyzed to study LV IVPD during early diastole. Reproducibility of the IVPD analysis was assessed, IVPD estimates from BST and color M mode were compared, and the validity of the BST-based IVPD calculations was tested in a computer flow model. RESULTS: Mean IVPD was significantly higher in controls (-2.28 ± 0.62 mm Hg) compared with in DCM (-1.21 ± 0.39 mm Hg, P < .001) and HCM (-1.57 ± 0.47 mm Hg, P < .001) patients. Feasibility was 88.3% in controls, 80% in DCM patients, and 90.4% in HCM patients. The peak relative negative pressure occurred earlier at the apex than at the base and preceded the peak E-wave LV filling velocity, indicating that it represents diastolic suction. Intraclass correlation coefficients for intra- and interobserver variability were 0.908 and 0.702, respectively. There was a nonsignificant mean difference of 0.15 mm Hg between IVPD from BST and color M mode. Estimation from two-dimensional velocities revealed a difference in peak IVPD of 0.12 mm Hg (6.6%) when simulated in a three-dimensional fluid mechanics model. CONCLUSIONS: Intraventricular pressure difference calculation from BST is highly feasible and provides information on diastolic suction and early filling in children with heart disease. Intraventricular pressure difference was significantly reduced in children with DCM and HCM compared with controls, indicating reduced early diastolic suction in these patient groups.

Probabilistic Maritime Trajectory Prediction in Complex Scenarios Using Deep Learning.

Maritime activity is expected to increase, and therefore also the need for maritime surveillance and safety. Most ships are obligated to identify themselves with a transponder system like the Automatic Identification System (AIS) and ships that do not, intentionally or unintentionally, are referred to as dark ships and must be observed by other means. Knowing the future location of ships can not only help with ship/ship collision avoidance, but also with determining the identity of these dark ships found in, e.g., satellite images. However, predicting the future location of ships is inherently probabilistic and the variety of possible routes is almost limitless. We therefore introduce a Bidirectional Long-Short-Term-Memory Mixture Density Network (BLSTM-MDN) deep learning model capable of characterising the underlying distribution of ship trajectories. It is consequently possible to predict a probabilistic future location as opposed to a deterministic location. AIS data from 3631 different cargo ships are acquired from a region west of Norway spanning 320,000 sqkm. Our implemented BLSTM-MDN model characterizes the conditional probability of the target, conditioned on an input trajectory using an 11-dimensional Gaussian distribution and by inferring a single target from the distribution, we can predict several probable trajectories from the same input trajectory with a test Negative Log Likelihood loss of -9.96 corresponding to a mean distance error of 2.53 km 50 min into the future. We compare our model to both a standard BLSTM and a state-of-the-art multi-headed self-attention BLSTM model and the BLSTM-MDN performs similarly to the two deterministic deep learning models on straight trajectories, but produced better results in complex scenarios.

Optical coherence tomography angiography measured area of retinal neovascularization is predictive of treatment response and progression of disease in patients with proliferative diabetic retinopathy.

BACKGROUND: The purpose of this study was to evaluate the area of retinal neovascularization in patients with treatment-naïve proliferative diabetic retinopathy (PDR) as measured by optical coherence tomography angiography (OCT-A) as a marker of subsequent treatment response after panretinal photocoagulation (PRP), and to examine if this area correlated with area of retinal neovascularization as measured by fluorescein angiography (FA). METHODS: En face OCT-A scans (4.5 × 4.5 mm) of neovascularizations were obtained at baseline (BL) before PRP and at month (M) 3 and M6 after treatment. Progression of PDR were defined as lesion growth (assessed by ophthalmoscopy and wide-field fundus photo) or increasing leakage by Optos ultra-widefield FA, and patients were divided into two groups; progression or non-progression. Mann-Whitney U test and Wilcoxon signed-rank test were used to analyse differences between groups and between time points. Areas of retinal neovascularizations (OCT-A and FA) were calculated by algorithms developed in Python (version 3.6.8, The Python Software Foundation, USA). RESULTS: Of 21 eyes included, 14 had progression of disease. Median OCT-A area did not differ between the two groups (progression vs. non-progression) at BL (76.40 ± 162.03 vs. 72.62 ± 94.15, p = 0.43) but were statistically significantly larger in the progression group at M6 (276.69 ± 168.78 vs. 61.30 ± 70.90, p = 0.025). Median FA area did not differ in the progression vs. the non-progression group at BL (111.42 ± 143.08 vs. 60.80 ± 54.83, p = 0.05) or at M6 (200.12 ± 91.81 vs. 123.86 ± 162.16, p = 0.62). Intraclass correlation between area by OCT-A and FA was -5.99 (95% CI: -35.28-0.993), p = 0.71. CONCLUSIONS: In this study of patients with treatment-naïve PDR, we showed that increasing area of retinal neovascularizations measured by OCT-A at M6 indicated progression of disease after PRP treatment. Our results suggest that area by OCT-A reflects disease activity and that it can be used as an indicator to monitor the progression of PDR over time, and to evaluate treatment response six months after PRP. Trial registration https://clinicaltrials.gov (identifier: NCT03113006). Registered April 13, 2017.

Halogenation as a tool to tune antimicrobial activity of peptoids.

Antimicrobial peptides have attracted considerable interest as potential new class of antibiotics against multi-drug resistant bacteria. However, their therapeutic potential is limited, in part due to susceptibility towards enzymatic degradation and low bioavailability. Peptoids (oligomers of N-substituted glycines) demonstrate proteolytic stability and better bioavailability than corresponding peptides while in many cases retaining antibacterial activity. In this study, we synthesized a library of 36 peptoids containing fluorine, chlorine, bromine and iodine atoms, which vary by length and level of halogen substitution in position 4 of the phenyl rings. As we observed a clear correlation between halogenation of an inactive model peptoid and its increased antimicrobial activity, we designed chlorinated and brominated analogues of a known peptoid and its shorter counterpart. Short brominated analogues displayed up to 32-fold increase of the activity against S. aureus and 16- to 64-fold against E. coli and P. aeruginosa alongside reduced cytotoxicity. The biological effect of halogens seems to be linked to the relative hydrophobicity and self-assembly properties of the compounds. By small angle X-ray scattering (SAXS) we have demontrated how the self-assembled structures are dependent on the size of the halogen, degree of substitution and length of the peptoid, and correlated these features to their activity.

Functional Skills among Preschool Children with Cerebral Palsy - Assessment before and after Early Intervention.

Objective: To assess and evaluate the change in functional skills among children with cerebral palsy (CP) who participated in an intensified habilitation program. Methods: In this prospective longitudinal study, a cohort of 39 preschool children (2-5 years) with cerebral palsy (Gross Motor Function Classification System levels I-V) together with their parents participated in an intensified multidimensional habilitation program for 1 year. Activities strengthening functional skills were among the main interventions. The children were evaluated with the Pediatric Evaluation of Disability Inventory before and after the program period. Results: Only children at GMFCS levels I-II showed improvements in mobility and social function on norm-referenced scales. After the intervention period, these children scored similar to the mean for typically developing children of the same age on the social function domain. Conclusions: Functional skills among preschool children with CP, GMFCS levels I-II, seems strengthened after participation in an intensified habilitation program.

Lipidated Polyaza Crown Ethers as Membrane Anchors for DNA-Controlled Content Mixing between Liposomes.

The ability to manipulate and fuse nano-compartmentalized volumes addresses a demand for spatiotemporal control in the field of synthetic biology, for example in the bottom-up construction of (bio)chemical nanoreactors and for the interrogation of enzymatic reactions in confined space. Herein, we mix entrapped sub-attoliter volumes of liposomes (~135 nm diameter) via lipid bilayer fusion, facilitated by the hybridization of membrane-anchored lipidated oligonucleotides. We report on an improved synthesis of the membrane-anchor phosphoramidites that allows for a flexible choice of lipophilic moiety. Lipid-nucleic acid conjugates (LiNAs) with and without triethylene glycol spacers between anchor and the 17 nt binding sequence were synthesized and their fusogenic potential evaluated. A fluorescence-based content mixing assay was employed for kinetic monitoring of fusion of the bulk liposome populations at different temperatures. Data obtained at 50 °C indicated a quantitative conversion of the limiting liposome population into fused liposomes and an unprecedently high initial fusion rate was observed. For most conditions and designs only low leakage during fusion was observed. These results consolidate LiNA-mediated membrane fusion as a robust platform for programming compartmentalized chemical and enzymatic reactions.

Vesicle Self-Assembly of Monoalkyl Amphiphiles under the Effects of High Ionic Strength, Extreme pH, and High Temperature Environments.

Vesicles and other bilayered membranous structures can self-assemble from single hydrocarbon chain amphiphiles. Their formation and stability are highly dependent on experimental conditions such as ionic strength, pH, and temperature. The addition of divalent cations, for example, often results in the disruption of vesicles made of a single fatty acid species through amphiphile precipitation. However, membranes composed of amphiphile mixtures have been shown to be more resistant to low millimolar concentrations of divalent cations at room temperature. In this report, several mixtures of amphiphiles are examined for their propensity to self-assemble into membranous vesicular structures under extreme environmental conditions of low pH, high ionic strengths, and temperatures. In particular, mixtures of decylamine with polar cosurfactants were found to efficiently form membranes under these conditions far away from those normally supporting vesicle formation. We further examined decanoic acid/decylamine mixtures in detail. At pH 2 in low ionic strength solutions, the amphiphiles formed oily or crystalline structures; however, the introduction of salts or/and strong acids in conjunction with high temperature induced a stable vesiculation. Thus, extreme environments, such as volcanic or vent environments whose environmental conditions are known to support high chemical reactivity, could have harbored and most significantly promoted the formation of simple organic compartments that preceded cells.

Effects of water-absorption and thermal drift on a polymeric photonic crystal slab sensor.

A photonic crystal slab (PCS) sensor is a universal refractive index sensor with possibilities and performance very similar to surface plasmon resonance (SPR), which represents the gold standard of biosensing. Cheap PCS sensors can be made vacuum-free entirely out of polymers, but come with additional challenges, besides those relating to temperature-variations, which must be considered in any refractive index based method: The polymeric waveguide core was found to swell by ∼0.3% as water absorbed into the waveguide core over ∼1.5 h. This was investigated by monitoring the wavelength of resonant reflection during absorption, by monitoring the release of water using ellipsometry, and by rigorous coupled-wave analysis (RCWA). The approach presented here enables monitoring of water uptake and thermal fluctuations, for drift-free, high-performance operation of a polymeric PCS sensor.

Enrichment of megabase-sized DNA molecules for single-molecule optical mapping and next-generation sequencing.

Next-generation sequencing (NGS) has caused a revolution, yet left a gap: long-range genetic information from native, non-amplified DNA fragments is unavailable. It might be obtained by optical mapping of megabase-sized DNA molecules. Frequently only a specific genomic region is of interest, so here we introduce a method for selection and enrichment of megabase-sized DNA molecules intended for single-molecule optical mapping: DNA from a human cell line is digested by the NotI rare-cutting enzyme and size-selected by pulsed-field gel electrophoresis. For demonstration, more than 600 sub-megabase- to megabase-sized DNA molecules were recovered from the gel and analysed by denaturation-renaturation optical mapping. Size-selected molecules from the same gel were sequenced by NGS. The optically mapped molecules and the NGS reads showed enrichment from regions defined by NotI restriction sites. We demonstrate that the unannotated genome can be characterized in a locus-specific manner via molecules partially overlapping with the annotated genome. The method is a promising tool for investigation of structural variants in enriched human genomic regions for both research and diagnostic purposes. Our enrichment method could potentially work with other genomes or target specified regions by applying other genomic editing tools, such as the CRISPR/Cas9 system.

Label-Free Monitoring of Diffusion in Microfluidics.

Label-free, real-time detection of concentration gradients is demonstrated in a microfluidic H-filter, using an integrated photonic crystal slab sensor to monitor sample refractive index with spatial resolution. The recorded diffusion profiles reveal root-mean-square diffusion lengths for non-fluorescing and non-absorbing molecules, both small (glucose, 180 Da) and large (bovine serum albumin, 67 kDa).

Executive functions in preschool children with cerebral palsy--Assessment and early intervention--A pilot study.

OBJECTIVE: To assess the level of executive functioning among preschool children with cerebral palsy (CP) and evaluate effects of the Program Intensified habilitation (PIH). METHODS: In this non-randomized, prospective study, 15 preschool children with CP, and their parents attended the PIH for a 1-year period. Executive functions were evaluated using the Behavior Rating Inventory of Executive functions-Preschool version (BRIEF-P), filled out by parents and preschool teachers. RESULTS: Before PIH, scores of executive function difficulties were close to the general population mean. After PIH, fathers and preschool teachers reported reduced levels of executive difficulties on, respectively, the Emergent Metacognition Index and the Flexibility Index on the BRIEF-P. Mothers reported no changes. CONCLUSION: The children in our sample showed age-appropriate levels of executive functions before attending PIH. Some aspects of executive skills difficulties were reduced after PIH. Using BRIEF-P contributed to the differentiation of cognitive strengths and weaknesses among the children.

All-polymer photonic crystal slab sensor.

An all-polymer photonic crystal slab sensor is presented, and shown to exhibit narrow resonant reflection with a FWHM of less than 1 nm and a sensitivity of 31 nm/RIU when sensing media with refractive indices around that of water. This results in a detection limit of 4.5 × 10(-6) RIU when measured in conjunction with a spectrometer of 12 pm/pixel resolution. The device is a two-layer structure, composed of a low refractive index polymer with a periodically modulated surface height, covered with a smooth upper-surface high refractive index inorganic-organic hybrid polymer modified with ZrO2based nanoparticles. Furthermore, it is fabricated using inexpensive vacuum-less techniques involving only UV nanoreplication and polymer spin-casting, and is thus well suited for single-use biological and refractive index sensing applications.

Automation of a single-DNA molecule stretching device.

We automate the manipulation of genomic-length DNA in a nanofluidic device based on real-time analysis of fluorescence images. In our protocol, individual molecules are picked from a microchannel and stretched with pN forces using pressure driven flows. The millimeter-long DNA fragments free flowing in micro- and nanofluidics emit low fluorescence and change shape, thus challenging the image analysis for machine vision. We demonstrate a set of image processing steps that increase the intrinsically low signal-to-noise ratio associated with single-molecule fluorescence microscopy. Furthermore, we demonstrate how to estimate the length of molecules by continuous real-time image stitching and how to increase the effective resolution of a pressure controller by pulse width modulation. The sequence of image-processing steps addresses the challenges of genomic-length DNA visualization; however, they should also be general to other applications of fluorescence-based microfluidics.

Refractometric monitoring of dissolution and fluid flow with distributed feedback dye laser sensor.

Monitoring the dissolution of solid material in liquids and monitoring of fluid flow is of significant interest for applications in chemistry, food production, medicine, and especially in the fields of microfluidics and lab on a chip. Here, real-time refractometric monitoring of dissolution and fast fluid flow with DFB dye laser sensors with an optical imaging spectroscopy setup is presented. The dye laser sensors provide both low detection limits and high spatial resolution. It is demonstrated how the materials NaCl, sucrose, and bovine serum albumin show characteristic dissolution patterns. The unique feature of the presented method is a high frame rate of up to 20 Hz, which is proven to enable the monitoring of fast flow of a sucrose solution jet into pure water.

Defined DNA-mediated assemblies of gene-expressing giant unilamellar vesicles.

The technological aspects of artificial vesicles as prominent cell mimics are evolving toward higher-order assemblies of functional vesicles with tissuelike architectures. Here, we demonstrate the spatially controlled DNA-directed bottom-up synthesis of complex microassemblies and macroassemblies of giant unilamellar vesicles functionalized with a basic cellular machinery to express green fluorescent protein and specified neighbor-to-neighbor interactions. We show both that the local and programmable DNA pairing rules on the nanoscale are able to direct the microscale vesicles into macroscale soft matter assemblies and that the highly sensitive gene-expression machinery remains intact and active during multiple experimental steps. An in silico model recapitulates the experiments performed in vitro and covers additional experimental setups highlighting the parameters that control the DNA-directed bottom-up synthesis of higher-order self-assembled structures. The controlled assembly of a functional vesicle matrix may be useful not only as simplified natural tissue mimics but also as artificial scaffolds that could interact and support living cells.

Propofol modulates the lipid phase transition and localizes near the headgroup of membranes.

The compound 2,6-diisopropylphenol (Propofol, PRF) is widely used for inducing general anesthesia, but the mechanism of PRF action remains relatively poorly understood at the molecular level. This work examines the possibility that a potential mode of action of PRF is to modulate the lipid order in target membranes. The effect on monolayers and bilayers of dipalmitoyl-sn-glycero-3-phosphorylcholine (DPPC) was probed using Langmuir monolayer isotherms, differential scanning calorimetry (DSC), isothermal titration calorimetry (ITC) and molecular dynamics (MD) simulations. Increasing amounts of PRF in a DPPC monolayer causes a decrease in isothermal compressibility modulus at the phase transition. A partition constant for PRF in DPPC liposomes on the order of K≈1500 M(-1) was found, and the partitioning was found to be enthalpy-driven above the melting temperature (Tm). A decrease in Tm with PRF content was found whereas the bilayer melting enthalpy ΔHm remains almost constant. The last finding indicates that PRF incorporates into the membrane at a depth near the phosphatidylcholine headgroup, in agreement with our MD-simulations. The simulations also reveal that PRF partitions into the membrane on a timescale of 0.5 µs and has a cholesterol-like ordering effect on DPPC in the fluid phase. The vertical location of the PRF binding site in a bacterial ligand-gated ion channel coincides with the location found in our MD-simulations. Our results suggest that multiple physicochemical mechanisms may determine anesthetic potency of PRF, including effects on proteins that are mediated through the bilayer.

Evaluating the effectiveness and efficacy of unguided internet-based self-help intervention for the prevention of depression: a randomized controlled trial.

The Internet has the potential to increase the capacity and accessibility of mental health services. This study aimed to investigate whether an unguided Internet-based self-help intervention delivered without human support or guidance can reduce symptoms of depression in young people at risk of depression. The study also aimed to explore the usage of such sites in a real-life setting, to estimate the effects of the intervention for those who received a meaningful intervention dose and to evaluate user satisfaction. Young adults were recruited by means of a screening survey sent to all students at the University of Tromsø. Of those responding to the survey, 163 students (mean age 28.2 years) with elevated psychological distress were recruited to the trial and randomized to an Internet intervention condition or the waiting list control group. The Internet condition comprised a depression information website and a self-help Web application delivering automated cognitive behavioural therapy. The participants in the waiting list condition were free to access formal or informal help as usual. Two-thirds of the users who completed the trial initially reported an unmet need for help. The findings demonstrated that an unguided intervention was effective in reducing symptoms of depression and negative thoughts and in increasing depression literacy in young adults. Significant improvements were found at 2-month follow up. Internet-based interventions can be effective without tracking and thus constitute a minimal cost intervention for reaching a large number of people. User satisfaction among participants was high.

Specific and reversible DNA-directed self-assembly of oil-in-water emulsion droplets.

Higher-order structures that originate from the specific and reversible DNA-directed self-assembly of microscopic building blocks hold great promise for future technologies. Here, we functionalized biotinylated soft colloid oil-in-water emulsion droplets with biotinylated single-stranded DNA oligonucleotides using streptavidin as an intermediary linker. We show the components of this modular linking system to be stable and to induce sequence-specific aggregation of binary mixtures of emulsion droplets. Three length scales were thereby involved: nanoscale DNA base pairing linking microscopic building blocks resulted in macroscopic aggregates visible to the naked eye. The aggregation process was reversible by changing the temperature and electrolyte concentration and by the addition of competing oligonucleotides. The system was reset and reused by subsequent refunctionalization of the emulsion droplets. DNA-directed self-assembly of oil-in-water emulsion droplets, therefore, offers a solid basis for programmable and recyclable soft materials that undergo structural rearrangements on demand and that range in application from information technology to medicine.