Nopadiene: A Pinene-Derived Cyclic Diene as a Styrene Substitute for Fully Biobased Thermoplastic Elastomers.

The bicyclic 1,2-substituted, 1,3-diene monomer nopadiene (1R,5S)-2-ethenyl-6,6-dimethylbicyclo[3.1.1]hept-2-ene was successfully polymerized by anionic and catalytic polymerization. Nopadiene is produced either through a facile one-step synthesis from myrtenal via Wittig-olefination or via a scalable two-step reaction from nopol (10-hydroxymethylene-2-pinene). Both terpenoids originate from the renewable ß-pinene. The living anionic polymerization of nopadiene in apolar and polar solvents at 25 °C using organolithium initiators resulted in homopolymers with well-controlled molar masses in the range of 5.6-103.4 kg·mol-1 (SEC, PS calibration) and low dispersities (D) between 1.06 and 1.18. By means of catalytic polymerization with Me4CpSi(Me)2NtBuTiCl2 and (Flu)(Pyr)CH2Lu(CH2TMS)2(THF), the 1,4 and 3,4- microstructures of nopadiene are accessible in excellent selectivity. In pronounced contrast to other 1,3-dienes, the rigid polymers of the sterically demanding nopadiene showed an elevated glass temperature, Tg,∞ = 160 °C (in the limit of very high molar mass, Mn). ABA triblock copolymers with a central polymyrcene block and myrcene content of 60-75 mol %, with molar masses of 100-200 kg/mol were prepared by living anionic polymerization of the pinene-derivable monomers nopadiene and myrcene. This diene copolymerization resulted in thermoplastic elastomers displaying nanophase separation at different molar ratios (DSC, SAXS) and an upper service temperature about 30 K higher than that for traditional petroleum-derived styrenic thermoplastic elastomers due to the high glass temperature of polynopadiene. The materials showed good thermal stability at elevated temperatures under nitrogen (TGA), promising tensile strength and ultimate elongation of up to 1600%.

Two types of microplastics (polystyrene-HBCD and car tire abrasion) affect oxidative stress-related biomarkers in earthworm Eisenia andrei in a time-dependent manner.

Microplastics are small plastic fragments that are widely distributed in marine and terrestrial environments. While the soil ecosystem represents a large reservoir for plastic, research so far has focused mainly on the impact on aquatic ecosystems and there is a lack of information on the potentially adverse effects of microplastics on soil biota. Earthworms are key organisms of the soil ecosystem and are due to their crucial role in soil quality and fertility a suitable and popular model organism in soil ecotoxicology. Therefore, the aim of this study was to gain insight into the effects of environmentally relevant concentrations of microplastics on the earthworm Eisenia andrei on multiple levels of biological organization after different exposure periods. Earthworms were exposed to two types of microplastics: (1) polystyrene-HBCD and (2) car tire abrasion in natural soil for 2, 7, 14 and 28d. Acute and chronic toxicity and all subcellular investigations were conducted for all exposure times, avoidance behavior assessed after 48 h and reproduction after 28d. Subcellular endpoints included enzymatic biomarker responses, namely, carboxylesterase, glutathione peroxidase, acetylcholinesterase, glutathione reductase, glutathione S-transferase and catalase activities, as well as fluorescence-based measurements of oxidative stress-related markers and multixenobiotic resistance activity. Multiple biomarkers showed significant changes in activity, but a recovery of most enzymatic activities could be observed after 28d. Overall, only minor effects could be observed on a subcellular level, showing that in this exposure scenario with environmentally relevant concentrations based on German pollution levels the threat to soil biota is minimal. However, in areas with higher concentrations of microplastics in the environment, these results can be interpreted as an early warning signal for more adverse effects. In conclusion, these findings provide new insights regarding the ecotoxicological effects of environmentally relevant concentrations of microplastics on soil organisms.

Determination of tire wear markers in soil samples and their distribution in a roadside soil.

Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0-2, 2-5, 5-10, and 10-20 cm. Four fine fractions, 1 000-500, 500-100, 100-50, and <50 µm, were analyzed. TW contents based on SBR ranged from 155 to 15 898 mg kg-1. TW contents based on zinc were between 413 and 44 812 mg kg-1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance. The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation.

Beneficial effects of dynamic groundwater flow and redox conditions on Natural Attenuation of mono-, poly-, and NSO-heterocyclic hydrocarbons.

Natural Attenuation (NA) processes have been demonstrated to reduce pollutant loads at different contaminated groundwater sites world-wide and are increasingly considered in contaminated site management concepts. However, data are mainly available for steady state groundwater flow and stable redox conditions as well as pollutants listed in standard regulatory schemes. In this study, the influence of transient groundwater flow and redox conditions on NA was examined at a former gas works site near the river Rhine in Germany. The investigated 78 pollutants included 40 mono- and polyaromatic hydrocarbons (MAHs, PAHs) and 38 NSO-heterocyclic aromatic hydrocarbons (NSO-HET). In the highly polluted areas, the MAHs benzene, indene and indane, the PAHs naphthalene, acenaphthene, 1- and 2-methylnaphthalene and the NSO-HET 2-methylquinoline, carbazole, benzothiophene, dibenzofuran and benzofuran were predominant. Pollutant concentrations decreased with increasing distance from the sources of contamination. At the plume fringes, the MAHs benzene and indane, the PAH acenaphthene, the NSO-HET carbazole, 5-methylbenzothiophene, 2- and 3-methylbenzofuran and 2-methyldibenzofuran were predominant, indicating low retention and slow intrinsic biodegradation of these compounds. The influence of surface water on groundwater level, pollutant concentrations, and redox conditions in the monitoring wells was observed with a permanently installed groundwater sensor. The temporary availability of oxygen was observed at the plume fringes, resulting in aerobic and ferric iron reducing biodegradation processes. Field and laboratory data were used to set-up a groundwater flow and reactive transport model used for quantification of the field mass transfer rates. In conclusion, the study demonstrates that NA is effective under transient flow and redox conditions. A conceptual model and reactive transport simulation can facilitate the interpretation of pronounced fluctuations of pollutant concentration in monitoring wells. Based on the analysis of 78 pollutants, indane, indene and several NSO-HET like carbazole, benzothiophene and 2-methyldibenzofuran are recommended for monitoring at tar oil polluted sites, besides EPA-PAHs and BTEX.

A multi-centre, randomized, controlled trial on coaching and telemonitoring in patients with cystic fibrosis: conneCT CF.

BACKGROUND: The extend of lung disease remains the most important prognostic factor for survival in patients with cystic fibrosis (CF), and lack of adherence is the main reason for treatment failure. Early detection of deterioration in lung function and optimising adherence are therefore crucial in CF care. We implement a randomized controlled trial to evaluate efficacy of telemonitoring of adherence, lung function, and health condition in combination with behavior change interventions using innovative digital technologies. METHODS: This is a multi-centre, randomized, controlled, non-blinded trial aiming to include 402 patients ≥ 12 years-of-age with CF. A standard-of-care arm is compared to an arm receiving objective, continuous monitoring of adherence to inhalation therapies, weekly home spirometry using electronic devices with data transmission to patients and caring physicians combined with video-conferencing, a self-management app and professional telephone coaching. The duration of the intervention phase is 18 months. The primary endpoint is time to the first protocol-defined pulmonary exacerbation. Secondary outcome measures include number of and time between pulmonary exacerbations, adherence to inhalation therapy, changes in forced expiratory volume in 1 s from baseline, number of hospital admissions, and changes in health-related quality of life. CF-associated medical treatment and care, and health care related costs will be assessed by explorative analysis in both arms. DISCUSSION: This study offers the opportunity to evaluate the effect of adherence interventions using telemedicine capable devices on adherence and lung health, possibly paving the way for implementation of telemedicine in routine care for patients with CF. TRIAL REGISTRATION: This study has been registered with the German Clinical Trials Register (Identifier: DRKS00024642, date of registration 01 Mar 2021, URL: https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00024642 ).

Quality of life in patients with limited (1-3) brain metastases undergoing stereotactic or whole brain radiotherapy : A prospective study of the DEGRO QoL working group.

PURPOSE: Published results of quality of life (QoL) studies mostly concern whole brain radiotherapy for limited or multiple brain metastases. This prospective multicentre study was designed to compare the QoL of patients with limited (1-3) brain metastases treated with either whole brain (WBRT) or stereotactic radiotherapy (SRT). METHODS: From 01/2007-03/2011, 90 limited brain metastases patients who were previously untreated (n = 77) or had undergone primary surgery (n = 13) were recruited at 14 centres in Germany and Austria. QoL was measured with the EORTC-QLQ-C15-PAL and BN20 brain modules before the start of radiotherapy and after 3 months. RESULTS: Fifty-two patients (58%) received WBRT and 38 (42%) received SRT. At 3 months, 67 patients (74%) were still living, and 92.6% of the 3­month survivors completed the second set of questionnaires. Analysis of the QLQ-C15-PAL and BN20 scales revealed significant deterioration in patients treated with WBRT and SRT in physical function (p < 0.001 and p = 0.007), fatigue (p < 0.001 and p = 0.036), nausea (p = 0.003 and p = 0.002), appetite loss (p < 0.001 and p = 0.025), drowsiness (p < 0.001 and p = 0.011), hair loss (p = 0.019 and p = 0.023) and itchy skin (p = 0.030 and p = 0.018). Motor dysfunction (p < 0.001), communication deficits (p = 0.002) and leg weakness (p < 0.001) declined significantly only in patients treated with WBRT. Comparing the two radiotherapy techniques over time, the results showed significant differences in symptom scores for future uncertainty, fatigue and appetite loss. CONCLUSIONS: QoL data as an outcome of the paper should be considered in decision making on the irradiation technique in patients with small number of brain metastases. Larger studies are required to verify the results according to subgroups.

Ecotoxicity of Nitrogen, Sulfur, or Oxygen Heterocycles and Short-Chained Alkyl Phenols Commonly Detected in Contaminated Groundwater.

Nitrogen, sulfur, or oxygen heterocyclic aromatic hydrocarbons (NSO-HETs) and short-chained alkyl phenols (SCAPs) are commonly detected in groundwater at contaminated sites and in the surrounding environment. It is now scientific consensus that these chemicals pose a risk to human and ecosystem health. However, toxicity data are comparably fragmentary, and only few studies have addressed the ecotoxicity of NSO-HETs and SCAPs in a systematic and comparative fashion. To overcome this shortcoming, we tested 18 SCAPs, 16 NSO-HETs, as well as the homocyclic hydrocarbons indane and indene in the Microtox® assay with Aliivibrio fischeri, the growth inhibition test with Desmodesmus subspicatus, the acute immobilization assay with Daphnia magna, as well as the fish embryo toxicity test with embryos of the zebrafish (Danio rerio). Because of the physicochemical properties of the tested chemicals (limited water solubility, volatility, and sorption to test vessels), actual exposure concentrations in test media and their dissipation over time were analytically quantified by means of gas chromatography with mass spectrometry. Analytically corrected effect levels (median effect and lethal concentrations) ranged from 0.017 to 180 mg L-1 , underlining the environmental relevance of some NSO-HETs and SCAPs. Para-substituted phenols showed the overall greatest toxicities in all 4 toxicity tests. We provide, for the first time, a complete high-quality data set in support of better environmental risk assessments of these chemicals. Environ Toxicol Chem 2019;38:1343-1355. © 2019 SETAC.

The effect of polymer aging on the uptake of fuel aromatics and ethers by microplastics.

Microplastics are increasingly entering marine, limnic and terrestrial ecosystems worldwide, where they sorb hydrophobic organic contaminants. Here, the sorption behavior of the fuel-related water contaminants benzene, toluene, ethyl benzene and xylene (BTEX) and four tertiary butyl ethers to virgin and via UV radiation aged polypropylene (PP) and polystyrene (PS) pellets was investigated. Changes in material properties due to aging were recorded using appropriate polymer characterization methods, such as differential scanning calorimetry, Fourier transform infrared spectroscopy, gel permeation chromatography, X-ray photoelectron spectroscopy, and microscopy. Pellets were exposed to water containing BTEX and the ethers at 130-190 µg L-1 for up to two weeks. Aqueous sorbate concentrations were determined by headspace gas chromatography. Sorption to the polymers was correlated with the sorbate's Kow and was significant for BTEX and marginal for the ethers. Due to substantially lower glass transition temperatures, PP showed higher sorption than PS. Aging had no effect on the sorption behavior of PP. PS sorbed less BTEX after aging due to an oxidized surface layer.

Outer Membrane Vesicles Facilitate Trafficking of the Hydrophobic Signaling Molecule CAI-1 between Vibrio harveyi Cells.

Many bacteria use extracellular signaling molecules to coordinate group behavior, a process referred to as quorum sensing (QS). However, some QS molecules are hydrophobic in character and are probably unable to diffuse across the bacterial cell envelope. How these molecules are disseminated between bacterial cells within a population is not yet fully understood. Here, we show that the marine pathogen Vibrio harveyi packages the hydrophobic QS molecule CAI-1, a long-chain amino ketone, into outer membrane vesicles. Electron micrographs indicate that outer membrane vesicles of variable size are predominantly produced and released into the surroundings during the stationary phase of V. harveyi, which correlates with the timing of CAI-1-dependent signaling. The large vesicles (diameter, <55 nm) can trigger a QS phenotype in CAI-1-nonproducing V. harveyi and Vibrio cholerae cells. Packaging of CAI-1 into outer membrane vesicles might stabilize the molecule in aqueous environments and facilitate its distribution over distances.IMPORTANCE Formation of membrane vesicles is ubiquitous among bacteria. These vesicles are involved in protein and DNA transfer and offer new approaches for vaccination. Gram-negative bacteria use hydrophobic signaling molecules, among others, for cell-cell communication; however, due to their hydrophobic character, it is unclear how these molecules are disseminated between bacterial cells. Here, we show that the marine pathogen Vibrio harveyi packages one of its QS molecules, the long-chain ketone CAI-1, into outer membrane vesicles (OMVs). Isolated CAI-1-containing vesicles trigger a QS phenotype in CAI-1 nonproducing V. harveyi and also in Vibrio cholerae cells. Packaging of CAI-1 into OMVs not only solubilizes, stabilizes, and concentrates this class of molecules, but facilitate their distribution between bacteria that live in aqueous environments.

A statistical model for improved membrane protein expression using sequence-derived features.

The heterologous expression of integral membrane proteins (IMPs) remains a major bottleneck in the characterization of this important protein class. IMP expression levels are currently unpredictable, which renders the pursuit of IMPs for structural and biophysical characterization challenging and inefficient. Experimental evidence demonstrates that changes within the nucleotide or amino acid sequence for a given IMP can dramatically affect expression levels, yet these observations have not resulted in generalizable approaches to improve expression levels. Here, we develop a data-driven statistical predictor named IMProve that, using only sequence information, increases the likelihood of selecting an IMP that expresses in Escherichia coli The IMProve model, trained on experimental data, combines a set of sequence-derived features resulting in an IMProve score, where higher values have a higher probability of success. The model is rigorously validated against a variety of independent data sets that contain a wide range of experimental outcomes from various IMP expression trials. The results demonstrate that use of the model can more than double the number of successfully expressed targets at any experimental scale. IMProve can immediately be used to identify favorable targets for characterization. Most notably, IMProve demonstrates for the first time that IMP expression levels can be predicted directly from sequence.

Anionic Copolymerization Enables the Scalable Synthesis of Alternating (AB)n Multiblock Copolymers with High Molecular Weight in n/2 Steps.

Based on the highly disparate reactivities of isoprene (I, rI = 25.4) and 4-methylstyrene (4MS, r4MS = 0.007) in the anionic copolymerization in nonpolar media, a general strategy for the rapid and scalable synthesis of tapered multiblock copolymers with an extremely steep gradient has been developed. A repetitive addition strategy of a mixture of isoprene and 4MS leads to a tapered diblock in each case, giving access to linear alternating multiblock copolymers of the (AB)n type with up to 10 blocks. All multiblock copolymers showed narrow molecular weight distributions (dispersity D = 1.04-1.12). High molecular weights in the range of 80 to 400 kg mol-1 were achieved. Due to the incompatibility of PI and P4MS segments, the multiblock copolymers exhibit nanophase separation, manifested by separate glass transitions for both constituents. Stress-strain measurements revealed extraordinary toughness and elongations up to 1150% strain at break, even at a 50/50 molar ratio I/4MS (i.e., 37 wt% isoprene). Our synthesis permits access to a wide range of tapered multiblock copolymer architectures with rigid (P4MS, high glass transition, Tg) and flexible (low Tg) chains, in n/2 steps, while keeping overall dispersity low.

Hospital time prior to death and pancreas histopathology: implications for future studies.

AIMS/HYPOTHESIS: Diabetes research studies routinely rely upon the use of tissue samples from human organ donors. It remains unclear whether the length of hospital stay prior to organ donation affects the presence of cells infiltrating the pancreas or the frequency of replicating beta cells. METHODS: To address this, 39 organ donors without diabetes were matched for age, sex, BMI and ethnicity in groups of three. Within each group, donors varied by length of hospital stay immediately prior to organ donation (<3 days, 3 to <6 days, or ≥6 days). Serial sections from tissue blocks in the pancreas head, body and tail regions were immunohistochemically double stained for insulin and CD45, CD68, or Ki67. Slides were electronically scanned and quantitatively analysed for cell positivity. RESULTS: No differences in CD45+, CD68+, insulin+, Ki67+ or Ki67+/insulin+ cell frequencies were found when donors were grouped according to duration of hospital stay. Likewise, no interactions were observed between hospitalisation group and pancreas region, age, or both; however, with Ki67 staining, cell frequencies were greater in the body vs the tail region of the pancreas (∆ 0.65 [unadjusted 95% CI 0.25, 1.04]; p = 0.002) from donors <12 year of age. Interestingly, frequencies were less in the body vs tail region of the pancreas for both CD45+ cells (∆ -0.91 [95% CI -1.71, -0.10]; p = 0.024) and insulin+ cells (∆ -0.72 [95% CI -1.10, -0.34]; p < 0.001). CONCLUSIONS/INTERPRETATION: This study suggests that immune or replicating beta cell frequencies are not affected by the length of hospital stay prior to donor death in pancreases used for research. DATA AVAILABILITY: All referenced macros (adopted and developed), calculations, programming code and numerical dataset files (including individual-level donor data) are freely available on GitHub through Zenodo at https://doi.org/10.5281/zenodo.1034422.

Interfacial Assembly and Jamming Behavior of Polymeric Janus Particles at Liquid Interfaces.

The self-assembly and interfacial jamming of spherical Janus nanoparticles (JNPs) at the water/oil interface were investigated. Polymeric JNPs, made by cross-linking polystyrene-block-polybutadiene-block-poly(methyl methacrylate) (PS-PB-PMMA), with a high interfacial activity assemble at the water/oil interface. During the self-assembly at the interface, the interfacial energy was reduced and a dynamic interlayer was observed that is responsive to the pH of the aqueous phase. Unlike hard particles, the JNPs are composed of polymer chains that can spread at the liquid-liquid interface to maximize coverage at relatively low areal densities. In a pendant drop geometry, the interfacial area of a water droplet in oil was significantly decreased and the JNPs were forced to pack more closely. Entangling of the polymer chains causes the JNPs to form a solid-like interfacial assembly, resulting in the formation of wrinkles when the interfacial area is decreased. The wrinkling behavior, the retention of the wrinkles, or the slow relaxation of the liquid drop back to its original equilibrium shape was found to depend upon the pH.

The inheritance of a Mesozoic landscape in western Scandinavia.

In-situ weathered bedrock, saprolite, is locally found in Scandinavia, where it is commonly thought to represent pre-Pleistocene weathering possibly associated with landscape formation. The age of weathering, however, remains loosely constrained, which has an impact on existing geological and landscape evolution models and morphotectonic correlations. Here we provide new geochronological evidence that some of the low-altitude basement landforms on- and offshore southwestern Scandinavia are a rejuvenated geomorphological relic from Mesozoic times. K-Ar dating of authigenic, syn-weathering illite from saprolitic remnants constrains original basement exposure in the Late Triassic (221.3±7.0-206.2±4.2 Ma) through deep weathering in a warm climate and subsequent partial mobilization of the saprolitic mantle into the overlying sediment cascade system. The data support the bulk geomorphological development of west Scandinavia coastal basement rocks during the Mesozoic and later, long-lasting relative tectonic stability. Pleistocene glaciations played an additional geomorphological role, selectively stripping the landscape from the Mesozoic overburden and carving glacial landforms down to Plio-Pleistocene times. Saprolite K-Ar dating offers unprecedented possibilities to study past weathering and landscape evolution processes.

Compaction and Transmembrane Delivery of pDNA: Differences between l-PEI and Two Types of Amphiphilic Block Copolymers.

Polycations are popular agents for nonviral delivery of DNA to mammalian cells. Adding hydrophobic, biodegradable, or cell-penetrating functions could help to improve their performance, which at present is below that of viral agents. A crucial first step in gene delivery is the complexation of the DNA. The characteristics of these "polyplexes" presumably influence or even determine the subsequent steps of membrane passage, intracellular traveling/DNA release, and nuclear uptake. Herein, polyplexes formed with linear poly(ethylenimine) (l-PEI) are compared to complexes generated with functionalized diblock copolymers. While l-PEI interacts only electrostatically with the DNA, interaction in the case of the diblock polymers may be mixed-mode. In certain cases, transfection efficiency improved when the polyplexes were formed in hypertonic solution. Moreover, whereas conventional PEI-based polyplexes enter the cells via endocytosis, at least one of the diblock agents seemed to promote entry via transient destabilization of the plasma membrane.

Systematic Study of a Library of PDMAEMA-Based, Superparamagnetic Nano-Stars for the Transfection of CHO-K1 Cells.

The introduction of the DNA into mammalian cells remains a challenge in gene delivery, particularly in vivo. Viral vectors are unmatched in their efficiency for gene delivery, but may trigger immune responses and cause severe side-reactions. Non-viral vectors are much less efficient. Recently, our group has suggested that a star-shaped structure improves and even transforms the gene delivery capability of synthetic polycations. In this contribution, this effect was systematically studied using a library of highly homogeneous, paramagnetic nano-star polycations with varied arm lengths and grafting densities. Gene delivery was conducted in CHO-K1 cells, using a plasmid encoding a green fluorescent reporter protein. Transfection efficiencies and cytotoxicities varied systematically with the nano-star architecture. The arm density was particularly important, with values of approximately 0.06 arms/nm² yielding the best results. In addition, a certain fraction of the cells became magnetic during transfection. The gene delivery potential of a nano-star and its ability to render the cells magnetic did not have any correlations. End-capping the polycation arms with di(ethylene glycol) methyl ether methacrylate (PDEGMA) significantly improved serum compatibility under transfection conditions; such nano-stars are potential candidates for future in vivo testing.

A block copolymer-templated construction approach for the creation of nano-patterned polyelectrolyte multilayers and nanoscale objects.

A block copolymer-based assembly approach for the creation of nano-patterned polyelectrolyte multilayers over cm2-scale areas is presented. Up to 5 bi-layers were selectively assembled on top of specific nano-domains featuring different morphologies. The successful isolation of nanoscale objects corresponding in shape to the template features is also demonstrated. This methodology is applicable to different types of polyelectrolytes, and opens up a new dimension for layer-by-layer construction.

A Link between Integral Membrane Protein Expression and Simulated Integration Efficiency.

Integral membrane proteins (IMPs) control the flow of information and nutrients across cell membranes, yet IMP mechanistic studies are hindered by difficulties in expression. We investigate this issue by addressing the connection between IMP sequence and observed expression levels. For homologs of the IMP TatC, observed expression levels vary widely and are affected by small changes in protein sequence. The effect of sequence changes on experimentally observed expression levels strongly correlates with the simulated integration efficiency obtained from coarse-grained modeling, which is directly confirmed using an in vivo assay. Furthermore, mutations that improve the simulated integration efficiency likewise increase the experimentally observed expression levels. Demonstration of these trends in both Escherichia coli and Mycobacterium smegmatis suggests that the results are general to other expression systems. This work suggests that IMP integration is a determinant for successful expression, raising the possibility of controlling IMP expression via rational design.

Rational design of ABC triblock terpolymer solution nanostructures with controlled patch morphology.

Block copolymers self-assemble into a variety of nanostructures that are relevant for science and technology. While the assembly of diblock copolymers is largely understood, predicting the solution assembly of triblock terpolymers remains challenging due to complex interplay of block/block and block/solvent interactions. Here we provide guidelines for the self-assembly of linear ABC triblock terpolymers into a large variety of multicompartment nanostructures with C corona and A/B cores. The ratio of block lengths NC/NA thereby controls micelle geometry to spheres, cylinders, bilayer sheets and vesicles. The insoluble blocks then microphase separate to core A and surface patch B, where NB controls the patch morphology to spherical, cylindrical, bicontinuous and lamellar. The independent control over both parameters allows constructing combinatorial libraries of unprecedented solution nanostructures, including spheres-on-cylinders/sheets/vesicles, cylinders-on-sheets/vesicles, and sheets/vesicles with bicontinuous or lamellar membrane morphology (patchy polymersomes). The derived parameters provide a logical toolbox towards complex self-assemblies for soft matter nanotechnologies.