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Natural materials, such as collagen, can assemble with multiple levels of organization in solution. Achieving a similar degree of control over morphology, stability and hierarchical organization with equilibrium synthetic materials remains elusive. For the assembly of peptidic materials the process is controlled by a complex interplay between hydrophobic interactions, electrostatics and secondary structure formation. Consequently, fine tuning the thermodynamics and kinetics of assembly remains extremely challenging. Here, we synthesized a set of block co polypeptides with varying hydrophobicity and ability to form secondary structure. From this set we select a sequence with balanced interactions that results in the formation of high-aspect ratio thermodynamically favored nanotubes, stable between pH 2 and 12 and up to 80 °C. This stability permits their hierarchical assembly into bundled nanotube fibers by directing the pH and inducing complementary zwitterionic charge behavior. This block co-polypeptide design strategy, using defined sequences, provides a straightforward approach to creating complex hierarchical peptide-based assemblies with tunable interactions.

Morphology plays an essential role in chemistry through the segregation of atoms and/or molecules into different phases, delineated by interfaces. This is a general process in materials synthesis and exploited in many fields including colloid chemistry, heterogeneous catalysis, and functional molecular systems. To rationally design complex materials, we must understand and control morphology evolution. Toward this goal, we utilize cryogenic transmission electron microscopy (cryoTEM), which can track the structural evolution of materials in solution with nanometer spatial resolution and a temporal resolution of

In the present numerical study, we propose a new passive flow control mechanism at the Reynolds number of 3900. The novel method benefits from making grooves in the cylinder wall while the grooves are filled with porous materials of a specific permeability. According to the literature survey, while the porous medium is potentially an effective noise control method, it has serious drawbacks, mainly significant pressure drop. In the present study, instead of a porous coating, porous fillers are introduced offering substantial reduction of the noise level, in addition to managing the hydrodynamic parameters. To find a suitable design for the grooves and porous fillers, a systematic parametric study is performed on the number, sequence and size of the grooves, as well as the porous fillers' permeabilities. Based on the results, the newly proposed method dominated the traditional full porous coating by limiting the turbulent kinetic energy (TKE). The results of the parametric study indicated that grooves at an angle of 90° relative to the front stagnation point reduced the overall sound pressure level (OASPL) by 1.25 dB; meanwhile, the high-intensity TKE region shrunk. Further reductions were achieved by deeper grooves and porous fillers, as the drag coefficient, the lift coefficient, the Strouhal number, and the OASPL reduced up to 40.2%, 27.4%, 10.6%, and 3 dB, respectively. The proposed passive control method will be helpful for various industrial applications of cylinders through rigorous control of aerodynamic parameters and the noise level. [ABSTRACT FROM AUTHOR]

Introduction: Emergency Medical Services (EMS) is one of the vital links in the care chain, and its services need to be improved. These services can be available through mobile-based automation system, in which low usability level of these systems lead to decrease the acceptance, satisfaction, and confidence of users especially the emergency care team. The purpose of this study was the usability evaluation of a national mobile- based automation system among the pre-hospital emergency care team. Material and Methods: This cross-sectional study was conducted on prehospital emergency care team members in Semnan and Shahroud Universities of Medical Sciences in 2022. The usability evaluation of the mobile- based EMS automation system was done using the Software Usability Measurement Inventory (SUMI) questionnaire. Multiple logistic regression models were used to analyze data. Results: One hundred eighty-eight EMS team members from the 31 EMS centers in Semnan province participated in present study. The mean total usability score was 61.93±15.37, the highest mean score was related to the efficiency feature (67.19±19.85) and the lowest mean score was related to the learnability feature (48.21±29.29). There was a reverse and significant relationship between being a manager and the agreement with the usability (p=0.04, OR= -3.383, CI 95%=0.389-29549). Conclusion: This study showed that although an automation system may be widely used in a country, its usability could be at a low level. In order to improve the different function of these systems, it is suggested to participate various clinical experts include prehospital emergency care team in all stages of designing and developing these systems. [ABSTRACT FROM AUTHOR]

This study addresses the consensus problem of leader-following multiagent systems, whose dynamics are governed by time-delay linear parameter-varying models with norm-bounded uncertainties. At first, a delay-dependent sufficient condition concerned with the existence of a parameter-varying sliding surface is given in terms of linear matrix inequalities. Then, a robust consensus among the leader and followers is achieved via the distributed linear parameter-varying sliding mode control protocol. Conditions for closed-loop stability are also presented in the form of some theorems. Simulation results demonstrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Graphene liquid cells (GLCs) for transmission electron microscopy (TEM) enable high‐resolution, real‐time imaging of dynamic processes in water. Large‐scale implementation, however, is prevented by major difficulties in reproducing GLC fabrication. Here, a high‐yield method is presented to fabricate GLCs under millimeter areas of continuous graphene, facilitating efficient GLC formation on a TEM grid. Additionally, GLCs are located on the grid using correlated light‐electron microscopy (CLEM), which reduces beam damage by limiting electron exposure time. CLEM allows the acquisition of reliable statistics and the investigation of the most common shapes of GLCs. In particular, a novel type of liquid cell is found, formed from only a single graphene sheet, greatly simplifying the fabrication process. The methods presented in this work—particularly the reproducibility and simplicity of fabrication—will enable future application of GLCs for high‐resolution dynamic imaging of biomolecular systems. [ABSTRACT FROM AUTHOR]

Surface and subsurface drip irrigation systems have been applied to increase irrigation efficiency and uniformity, mainly in arid and semi-arid regions. Determining soil-wetting dimensions around a point source emitter is essential for better design of drip irrigation systems. Laboratory experiments were thus conducted to measure the soil-wetting front for various arrangements of surface and subsurface drip irrigation in terms of emitter number, installation depth and flow rate. The two-dimensional numerical model Hydrus-2D was used to simulate water movement around the emitter(s) in silty loam soil. The shapes of observed and simulated soil-wetting front were almost ellipsoid and spherical for surface and subsurface drip irrigation respectively. The 2D model proved better at estimating the dimensions of the soil-wetting front when using one emitter than when using two emitters for irrigation. Both simulations and observations indicated that wetting velocity was greater during irrigation than during soil moisture redistribution. The model under- and overpredicted wetting area during irrigation and redistribution respectively, but there were no significant differences between measured and predicted values of wetting area for surface and subsurface drip irrigation. The model generally proved effective in simulating soil water flow for various kinds of surface and subsurface drip irrigation systems in silty loam soils. [ABSTRACT FROM AUTHOR]

The composition and morphology of lipid-based nanoparticles can influence their overall in vivo behavior. Previously, we demonstrated that phase separation in liposomes composed of DSPC and a diacylglycerol lipid analogue (DOaG) drives the in vivo biodistribution towards a specific subset of endothelial cells in zebrafish embryos. In the absence of traditional targeting functionalities ( e.g. , antibodies, ligands), this selectivity is mediated solely by the unique liposome morphology and composition, characterized by a DOaG-rich lipid droplet within the DSPC-rich phospholipid bilayer. The phase separation is induced due to the geometry of DOaG lipid and its ability to create non-bilayer phases in lipid membranes. To investigate the underlying principles of phase separation and to optimize the liposome colloidal stability, we performed a structure-function relationship study by synthesizing a library of DOaG analogues with varying molecular properties, such as the number, length and sn -position of the acyl chains, as well as the degree of saturation or carbonyl substituents. We assessed the ability of these lipid analogues to assemble into phase-separated liposomes and studied their morphology, colloidal stability, and in vivo biodistribution in zebrafish embryos. We found that analogues containing unsaturated, medium length (C16-C18) fatty acids were required to obtain colloidally stable, phase-separated liposomes with cell-specific biodistribution patterns. Moreover, we observed that using the pure DOaG isomer, with acyl chains at the sn -1,3 positions, leads to more colloidally stable liposomes than when a mixture of sn -1,2 and sn -1,3 isomers is used. Similarly, we observed that incorporating a DOaG analogue with fatty tails shorter than DSPC, as well as PEGylation, endows liposomes with long term stability while retaining cell-selective biodistribution. Diacylglycerols are known to promote fusion, lipid polymorphism, signaling and protein recruitment on lipid membranes. In this study, we showed that diacylglycerol derivatives can induce phase separation in liposomes, unlocking the potential for cell-specific targeting in vivo . We believe that these findings can be the foundation for future use of diacylglycerols in lipid-based nanomedicines and could lead to the development of novel targeted delivery strategies.

In this study, native chemical ligation (NCL) was used as a selective cross-linking method to form core-cross-linked thermosensitive polymeric micelles for drug delivery applications. To this end, two complementary ABA triblock copolymers having polyethylene glycol (PEG) as midblock were synthesized by atom transfer radical polymerization (ATRP). The thermosensitive poly isopropylacrylamide (PNIPAM) outer blocks of the polymers were copolymerized with either N-(2-hydroxypropyl)methacrylamide-cysteine (HPMA-Cys), P(NIPAM- co-HPMA-Cys)-PEG-P(NIPAM- co-HPMA-Cys) (PNC) or N-(2-hydroxypropyl)methacrylamide-ethylthioglycolate succinic acid (HPMA-ETSA), P(NIPAM- co-HPMA-ETSA)-PEG-P(NIPAM- co-HPMA-ETSA) (PNE). Mixing of these polymers in aqueous solution followed by heating to 50 °C resulted in the formation of thermosensitive flower-like micelles. Subsequently, native chemical ligation in the core of micelles resulted in stabilization of the micelles with a Z-average of 65 nm at body temperature. Decreasing the temperature to 10 °C only affected the size of the micelles (increased to 90 nm) but hardly affected the polydispersity index (PDI) and aggregation number ( N agg ) confirming covalent stabilization of the micelles by NCL. CryoTEM images showed micelles with an uniform spherical shape and dark patches close to the corona of micelles were observed in the tomographic view. The dark patches represent more dense areas in the micelles which coincide with the higher content of HPMA-Cys/ETSA close to the PEG chain revealed by the polymerization kinetics study. Notably, this cross-linking method provides the possibility for conjugation of functional molecules either by using the thiol moieties still present after NCL or by simply adjusting the molar ratio between the polymers (resulting in excess cysteine or thioester moieties) during micelle formation. Furthermore, in vitro cell experiments demonstrated that fluorescently labeled micelles were successfully taken up by HeLa cells while cell viability remained high even at high micelle concentrations. These results demonstrate the potential of these micelles for drug delivery applications.