Insights into the Correlation of Microscopic Motions of [c2]Daisy Chains with Macroscopic Mechanical Performance for Mechanically Interlocked Networks.

Mimicking filament sliding in sarcomeres using artificial molecular muscles such as [c2]daisy chains has aroused increasing interest in developing advanced polymeric materials. Although few bistable [c2]daisy chain-based mechanically interlocked polymers (MIPs) with stimuli-responsive behaviors have been constructed, it remains a significant challenge to establish the relationship between microscopic responsiveness of [c2]daisy chains and macroscopic mechanical properties of the corresponding MIPs. Herein, we report two mechanically interlocked networks (MINs) consisting of dense [c2]daisy chains with individual extension (MIN-1) or contraction (MIN-2) conformations decoupled from a bistable precursor, which serve as model systems to address the challenge. Upon external force, the extended [c2]daisy chains in MIN-1 mainly undergo elastic deformation, which is able to assure the strength, elasticity, and creep resistance of the corresponding material. For the contracted [c2]daisy chains, long-range sliding motion occurs along with the release of latent alkyl chains between the two DB24C8 wheels, and accumulating lots of such microscopic motions endows MIN-2 with enhanced ductility and ability of energy dissipation. Therefore, by decoupling a bistable [c2]daisy chain into individual extended and contracted ones, we directly correlate the microscopic motion of [c2]daisy chains with macroscopic mechanical properties of MINs.

Effect of ice popsicle treatment on emergence agitation in children undergoing oral surgery with sevoflurane anaesthesia: A prospective randomized controlled study.

PURPOSE: Emergence agitation is a common postoperative complication during recovery in children. The purpose of this study is to explore whether the use of ice popsicle could prevent emergence agitation in children undergoing oral surgery with sevoflurane anaesthesia. DESIGN AND METHODS: In this prospective randomized controlled study, 100 children undergoing oral surgery were randomly assigned to Group 1 which received ice popsicle after emergence (intervention, n = 50) or Group 2 which received verbal encouragement from their parents (control, n = 50). The primary outcome was the 2-hour postoperative incidence of EA. RESULTS: Group 1 had a significant lower incidence of emergence agitation (22% vs 58%, P < 0.001) compared with Group 2. The mean agitation score was significantly lower in Group 1 vs Group 2 at 10  minutes (1.64 vs 2.12, P = 0.024) and 20 min (1.60 vs 2.14, P = 0.004) after emergence. The peak agitation and pain scores were significantly lower in Group 1 than in Group 2 (P < 0.001). CONCLUSIONS: Findings from this study suggest that ice popsicle is an effective, cheap, pleasurable, and easily administered method for alleviating emergence agitation in paediatric patients after oral surgery under general anaesthesia. These results are worthy of confirmation in other surgeries. PRACTICE IMPLICATIONS: This approach is highly accepted by both children and their parents, and our findings support the effectiveness of ice popsicle in relieving emergence agitation and pain after oral surgery in children. CLINICAL TRIALS REGISTRATION: Chinese Clinical Trial Registry, ChiCTR1800015634.

A molecular interaction-diffusion framework for predicting organic solar cell stability.

Rapid increase in the power conversion efficiency of organic solar cells (OSCs) has been achieved with the development of non-fullerene small-molecule acceptors (NF-SMAs). Although the morphological stability of these NF-SMA devices critically affects their intrinsic lifetime, their fundamental intermolecular interactions and how they govern property-function relations and morphological stability of OSCs remain elusive. Here, we discover that the diffusion of an NF-SMA into the donor polymer exhibits Arrhenius behaviour and that the activation energy Ea scales linearly with the enthalpic interaction parameters χH between the polymer and the NF-SMA. Consequently, the thermodynamically most unstable, hypo-miscible systems (high χ) are the most kinetically stabilized. We relate the differences in Ea to measured and selectively simulated molecular self-interaction properties of the constituent materials and develop quantitative property-function relations that link thermal and mechanical characteristics of the NF-SMA and polymer to predict relative diffusion properties and thus morphological stability.

Manipulating Conjugated Polymer Backbone Dynamics through Controlled Thermal Cleavage of Alkyl Side Chains.

The morphological stability of an organic photovoltaic (OPV) device is greatly affected by the dynamics of donors and acceptors occurring near the device's operational temperature. These dynamics can be quantified by the glass transition temperature (Tg ) of conjugated polymers (CPs). Because flexible side chains possess much faster dynamics, the cleavage of the alkyl side chains will reduce chain dynamics, leading to a higher Tg . In this work, the Tg s for CPs are systematically studied with controlled side chain cleavage. Isothermal annealing of polythiophenes featuring thermally cleavable side chains at 140 °C, is found to remove more than 95% of alkyl side chains in 24 h, and raise the backbone Tg from 23 to 75 °C. Coarse grain molecular dynamics simulations are used to understand the Tg dependence on side chain cleavage. X-ray scattering indicates that the relative degree of crystallization remains constantduring isothermal annealing process. The effective conjugation length is not influenced by thermal cleavage; however, the density of chromophore is doubled after the complete removal of alkyl side chains. The combined effect of enhancing Tg and conserving crystalline structures during the thermal cleavage process can provide a pathway to improving the stability of optoelectronic properties in future OPV devices.

Silica-based nanocapsules: synthesis, structure control and biomedical applications.

Synergistically combining the merits of silica (e.g., mechanical robustness, biocompatibility and great versatility in surface functionalization) and capsular configurations (e.g., a large inner cavity, low density and favourable colloidal properties), silica-based nanocapsules (SNCs) with a size cutoff of ∼100 nm have gained growing interest in encapsulating bioactive molecules for bioimaging and controlled delivery applications. Within this context, this review provides a comprehensive overview of the synthetic strategies, structural control and biomedical applications of SNCs. Special emphasis is placed on size control at the nanoscale and material composition manipulation of each strategy and the newly emerging synthetic strategies. The applications of SNCs in bioimaging/diagnosis and drug delivery/therapy and the structure engineering that is critically important for the bio-performance of SNCs are also addressed in this review.

Two new species of Tanaidacea (Crustacea, Peracarida) from Taiwan.

Two new species, representing the genus Aparatanais of the family Paratanaidae and the genus Tanais of the family Tanaidae (both families belonging to the suborder Tanaidomorpha), are described in the present study. The genus Aparatanais, the family Paratanaidae and the superfamily Paratanaoidea are recorded for the first time from Taiwan. Aparatanais lenoprimorum sp. nov. departs from its congeners by the lack of subdistal teeth on the superior margin of the right mandible and without serration on left mandible lacinia mobilis. Tanais nuwalianensis sp. nov. is distinguished from its most similar congener, Tanais tinhauae, by the presence of a much smaller right mandible lacinia mobilis, fewer carpal spines on pereopods 2-6, fewer leaf-like setae on the distal margin of the propodus of Pereopod 6, and fewer inner setae on the pleopod basis. Morphological comparisons between members of the genus Aparatanais, as well as the genus Tanais are tabulated.

Fluorine substituents reduce charge recombination and drive structure and morphology development in polymer solar cells.

Three structurally identical polymers, except for the number of fluorine substitutions (0, 1, or 2) on the repeat unit (BnDT-DTBT), are investigated in detail, to further understand the impact of these fluorine atoms on open circuit voltage (V(oc)), short circuit current (J(sc)), and fill factor (FF) of related solar cells. While the enhanced V(oc) can be ascribed to a lower HOMO level of the polymer by adding more fluorine substituents, the improvement in J(sc) and FF are likely due to suppressed charge recombination. While the reduced bimolecular recombination with raising fluorine concentration is confirmed by variable light intensity studies, a plausibly suppressed geminate recombination is implied by the significantly increased change of dipole moment between the ground and excited states (Δµ(ge)) for these polymers as the number of fluorine substituents increases. Moreover, the 2F polymer (PBnDT-DTffBT) exhibits significantly more scattering in the in-plane lamellar stacking and out-of-plane π-π stacking directions, observed with GIWAXS. This indicates that the addition of fluorine leads to a more face-on polymer crystallite orientation with respect to the substrate, which could contribute to the suppressed charge recombination. R-SoXS also reveals that PBnDT-DTffBT has larger and purer polymer/fullerene domains. The higher domain purity is correlated with an observed decrease in PCBM miscibility in polymer, which drops from 21% (PBnDT-DTBT) to 12% (PBnDT-DTffBT). The disclosed "fluorine" impact not only explains the efficiency increase from 4% of PBnDT-DTBT (0F) to 7% with PBnDT-DTffBT (2F) but also suggests fluorine substitution should be generally considered in the future design of new polymers.

Step-growth polymerization by the RAFT process.

Reversible Addition-Fragmentation Chain Transfer (RAFT) step-growth polymerization is an emerging method that synergistically combines the benefits of RAFT polymerization (functional group and user-friendly nature) and step-growth polymerization (versatility of the polymer backbone). This new polymerization method is generally achieved by using bifunctional reagents of monomer and Chain Transfer Agent (CTA), that efficiently yield Single Monomer Unit Insertion (SUMI) adducts under stoichiometrically balanced conditions. This review covers a brief history of the RAFT-SUMI process and its transformation into RAFT step-growth polymerization, followed by a comprehensive discussion of various RAFT step-growth systems. Furthermore, characterizing the molecular weight evolution of step-growth polymerization is elaborated based on the Flory model. Finally, a formula is introduced to describe the efficiency of the RAFT-SUMI process, assuming rapid chain transfer equilibrium. Examples of reported RAFT step-growth and SUMI systems are then categorized based on the driving force.

DPA-Zinc around Polyplexes Acts Like PEG to Reduce Protein Binding While Targeting Cancer Cells.

Gene therapy holds great promise as an effective treatment for many diseases of genetic origin. Gene therapy works by employing cationic polymers, liposomes, and nanoparticles to condense DNA into polyplexes via electronic interactions. Then, a therapeutic gene is introduced into target cells, thereby restoring or changing cellular function. However, gene transfection efficiency remains low in vivo due to high protein binding, poor targeting ability, and substantial endosomal entrapment. Artificial sheaths containing PEG, anions, or zwitterions can be introduced onto the surface of gene carriers to prevent interaction with proteins; however, they reduce the cellular uptake efficacy, endosomal escape, targeting ability, thereby, lowering gene transfection. Here, it is reported that linking dipicolylamine-zinc (DPA-Zn) ions onto polyplex nanoparticles can produce a strong hydration water layer around the polyplex, mimicking the function of PEGylation to reduce protein binding while targeting cancer cells, augmenting cellular uptake and endosomal escape. The polyplexes with a strong hydration water layer on the surface can achieve a high gene transfection even in a 50% serum environment. This strategy provides a new solution for preventing protein adsorption while improving cellular uptake and endosomal escape.

Structure-property optimizations in donor polymers via electronics, substituents, and side chains toward high efficiency solar cells.

Many advances in organic photovoltaic efficiency are not yet fully understood and new insight into structure-property relationships is required to push this technology into broad commercial use. The aim of this article is not to comprehensively review recent work, but to provide commentary on recent successes and forecast where researchers should look to enhance the efficiency of photovoltaics. By lowering the LUMO level, utilizing electron-withdrawing substituents advantageously, and employing appropriate side chains on donor polymers, researchers can elucidate further aspects of polymer-PCBM interactions while ultimately developing materials that will push past 10% efficiency.

Repurposing Mitsunobu Reactions as a Generic Approach toward Polyethylene Derivatives.

Broad scope of functionality and controllable degree of functionalization are intriguing goals for the development of polar-group-functionalized polyethylene materials. Herein, we propose a generic strategy of using widely available starting materials (i.e., poly(ethylene-co-vinyl acetate), EVA) and mild Mitsunobu functionalization conditions to prepare over 30 polyethylene derivatives. No noble transition metal catalysts (e.g., Ru, Mo, Pd, etc.) or corrosive/explosive reagents (e.g., HBr, NaN3, C2H4, H2, etc.) are used in the synthesis, while functional groups such as azide, aldehyde, norbornene, and thiol can be easily installed, with tunable content as high as 18 mol %. Using this practical method, we successfully prepared polyethylene-derivatized membranes with excellent antimicrobial and fluorescent properties.

Effect of osmotic ballast properties on the performance of a concentration gradient battery.

A concentration gradient battery (CGB) is an energy storage system comprised of a series of concentrated and dilute salt solution compartments, separated by ion exchange membranes (IEMs). The battery is charged by electrodialysis (ED), which increases the concentration gradient between these solutions, and discharged by reverse electrodialysis (RED), which allows these solutions to mix. In both ED and RED, water moves by osmosis from dilute to concentrated compartments, reducing the CGB faradaic and energy efficiency. A promising approach to mitigate osmosis is to use an osmotic ballast in the dilute solution to balance the osmotic pressure and reduce faradaic energy losses. The objective of this study was to investigate the impact of ballast properties (i.e., size, structure, end-group) on the faradaic and round-trip efficiency of the CGB. To accomplish this objective, we tested seven sugar and five glycol compounds as osmotic ballasts in a closed-loop cell. Results show that ballasts with high molecular weight generally resulted in higher faradaic efficiency and lower water transport compared with low molecular weight ballasts. Data also indicates that ballast with a cyclic structure (instead of linear), non-planar structure (instead of planar), and lower number of methyl end-groups led to lower water transport. Of all ballasts tested, sucrose performed best in terms of reducing non-ideal water transport (by 109%) and enhancing both faradaic and round-trip efficiencies (from 47.4% to 77.7% and 25.5% to 38.1%, respectively) compared with the non-ballasted CGB. Our results contribute to fundamental understanding of the impact of solute properties on water and small organic molecule transport in ion exchange membranes and indicate that ballasted CGBs can be further improved through development of optimized ballasts and selection of optimum membrane-ballast pairs. The improved understanding of ballast impact on CGB performance could be used for evaluation of potential ballast benefits in other membrane-based systems that may be impacted by osmosis such as the acid-base flow battery, waste heat recovery using RED, ED purification processes, osmotically assisted processes, and redox flow batteries.

RAFT Step-Growth Polymerization of Diacrylates.

RAFT step-growth polymerization was previously demonstrated with monomers that bear low rate of homopropagation to favor the chain transfer process; by contrast, acrylates are known to be fast homopropagating monomers, thereby posing serious challenges for RAFT step-growth. Here, we identified a chain transfer agent (CTA) that rapidly yields single unit monomer inserted (SUMI) CTA adducts with a model acrylate monomer. Using a bifunctional reagent of this CTA, we successfully demonstrated RAFT step-growth polymerization with diacrylates, yielding linear polymer backbones. Furthermore, we achieved inclusion of functionality (i.e., disulfide) into RAFT step-growth polymer via a disulfide incorporated bifunctional CTA. Grafting from this backbone resulted in molecular brush polymers with cleavable functionality in each repeat unit of the backbone, allowing selective degradation to afford well-defined unimolecular species of two polymeric side chains. Given the wide selection of commercially available diacrylates, RAFT step-growth polymerization of diacrylates will further enable facile synthesis of complex architectures with modular backbones.

Semi-paracrystallinity in semi-conducting polymers.

Precise determination of structural organization of semi-conducting polymers is of paramount importance for the further development of these materials in organic electronic technologies. Yet, prior characterization of some of the best-performing materials for transistor and photovoltaic applications, which are based on polymers with rigid backbones, often resulted in conundrums in which X-ray scattering and microscopy yielded seemingly contradicting results. Here we solve the paradox by introducing a new structural model, i.e., semi-paracrystalline organization. The model establishes that the microstructure of these materials relies on a dense array of small paracrystalline domains embedded in a more disordered matrix. Thus, the overall structural order relies on two parameters: the novel concept of degree of paracrystallinity (i.e., paracrystalline volume/mass fraction, introduced here for the first time) and the lattice distortion parameter of paracrystalline domains (g-parameter from X-ray scattering). Structural parameters of the model are correlated with long-range charge carrier transport, revealing that charge transport in semi-paracrystalline materials is particularly sensitive to the interconnection of paracrystalline domains.

Fluorine substituted conjugated polymer of medium band gap yields 7% efficiency in polymer-fullerene solar cells.

Recent research advances on conjugated polymers for photovoltaic devices have focused on creating low band gap materials, but a suitable band gap is only one of many performance criteria required for a successful conjugated polymer. This work focuses on the design of two medium band gap (~2.0 eV) copolymers for use in photovoltaic cells which are designed to possess a high hole mobility and low highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels. The resulting fluorinated polymer PBnDT-FTAZ exhibits efficiencies above 7% when blended with [6,6]-phenyl C(61)-butyric acid methyl ester in a typical bulk heterojunction, and efficiencies above 6% are still maintained at an active layer thicknesses of 1 µm. PBnDT-FTAZ outperforms poly(3-hexylthiophene), the current medium band gap polymer of choice, and thus is a viable candidate for use in highly efficient tandem cells. PBnDT-FTAZ also highlights other performance criteria which contribute to high photovoltaic efficiency, besides a low band gap.

Visualization of latent fingermarks on fabric using multi-metal deposition (MMD)-A preliminary study.

Multi-metal deposition (MMD) is a versatile fingermarks detection technique adapted from the colloidal gold biolabeling. However, the tedious procedures of MMD makes it receive little attention compared with other methods. The aim of this study is to evaluate the efficacy of MMD technique on several common fabrics, which is considered notoriously challenging for latent fingermark detection. Four different MMD formulations were examined to process fingermarks deposited on nylon taffeta, polyester taffeta, polyester pongee and cotton sateen to determine the most suitable one and the influence of aging and water immersion were also determined through subsequent experiments. It was found that MMD I outperformed other three formulations and obtained excellent results on nylon taffeta, polyester taffeta and satin ribbon, with polyester taffeta and satin ribbon providing more than 30% of identifiable marks even for fingermarks aged over 28 days. Cotton sateen and oxford cloth failed to produce ridge details but evidence of "touch" were successfully visualized, which may contribute to further DNA extraction. Water immersion did have some observable influence on the quality of detected marks as part of the MMD reactant within fingermarks lost during immersion, but the result from nylon taffeta and satin ribbon is still satisfying with the percentage of marks scored 3 and 4 reached 30%. The result of this study confirmed the capability of MMD I in treated with fingermarks on several kinds of fabrics, and shows potential to promote this non-instrumentation dependent technique.

Additions of new species to the Paratanaoidea (Crustacea, Tanaidacea) of Taiwan.

The present study reports one new species of the Family Leptocheliidae Lang, 1973 and one new species of Pseudotanaidae Sieg, 1976 from Taiwan. The leptocheliid Paraleptochelia setosa sp. nov. can be differentiated from its congeners by both sexes having a two-articled exopod and five-articled endopod on the uropod, the female having coupling hooks on the inner margin of the maxilliped endite, the male having a five-articled antennule flagellum, and cheliped fixed finger with one large subtriangular denticle on the incisive margin in some individuals. The pseudotanaid Akanthinotanais pedecerritulus sp. nov. can be distinguished from its congeners by pereopods 2 and 3 having a sigmoid (S-shaped) dactylus, a unique feature in Akanthinotanais. The family Pseudotanaidae and the two genera are reported from Taiwan for the first time, as are the two genera for the West Pacific. Key morphological characters of all known Paraleptochelia and Akanthinotanais species are tabulated.

Design and development of a new type of phimosis dilatation retractor for children.

BACKGROUND: Phimosis is one of the most common diseases in children. Early selection of appropriate treatment for phimosis in children is beneficial to the development of their reproductive organs and significantly improves the prognosis of phimosis in children. Although traditional circumcision is the most widely used, it has many disadvantages, including postoperative bleeding and incision infection, pain, obvious scars on the surgical incision, and unsatisfactory appearance. In addition, there is much controversy regarding treatment options and timing at home and abroad. Surgical procedures such as circumcision and cerclage for children with excessively long foreskin will greatly affect the normal life of children after the operation. Young children need general anesthesia, but this anesthesia carries a great risk. AIM: To design a new children phimosis dilatation retractor for children phimosis. METHODS: The children phimosis was dilated with an elastic dilation frame, in order to expand the foreskin mouth and expose the penis head, and after that, the phimosis was cured. RESULTS: A new type of phimosis dilatation retractor was designed, which can gently dilate the prepuce at multiple angles and in multiple directions at the same time. It has obtained the national patent for clinical application. CONCLUSION: The phimosis dilatation retractor based on the principle of elastically expanding the prepuce can achieve the purpose of expanding the phimosis. The clinical application shows that the effect of the children phimosis retractor is significant, which is worth promoting.

Hemorrhagic risk factors of endovascular onyx embolization of intracranial dural arteriovenous fistulas.

BACKGROUND AND PURPOSE: Hemorrhagic complication is a disastrous complication of intracranial dural arteriovenous fistulas (DAVFs) embolization. This study was to analyze the possible risk factors for the hemorrhagic complication caused by endovascular embolization of DAVFs. METHODS: From January 2012 to July 2016, a total of 267 patients with intracranial DAVFs received endovascular Onyx embolization at our hospital. The demographic information, clinical presentation, angiographic features, endovascular treatment and hemorrhagic complications were reviewed. Univariate and multivariate logistic regression analyses were performed to evaluate the risk factors contributing to the post-procedural hemorrhagic complications. RESULTS: In 267 patients of DAVF treated with endovascular embolization, procedure-related hemorrhagic complication occurred in 12 (4.5%) patients. Univariate and multivariate logistic regression analyses showed that the pial arterial supplier (OR 13.630; 95% CI, 1.556-119.368; P = 0.018), giant venous aneurysm (OR 15.196; 95% CI, 2.505-92.183; P = 0.003) and Onyx volume ≥ 6 ml (OR 1.138; 95% CI, 1.006-1.288; P = 0.040) were significant factors associated with these hemorrhagic complications. CONCLUSIONS: Hemorrhagic complications associated with endovascular DAVF embolization are not negligible. The pial arterial supplier, giant venous aneurysm and higher Onyx volume in one session may be risk factors for endovascular DAVF embolization.

Endovascular treatment of cerebellar arteriovenous malformations: A single-center experience of 75 consecutive patients.

AIM: We aimed to determine the safety and effectiveness of endovascular treatment for cerebellar arteriovenous malformations (AVMs). MATERIALS AND METHODS: Between January 2006 and January 2016, 75 patients with cerebellar AVMs underwent endovascular treatment at our department. The clinical and angiographic features, post-procedure complications, occlusion rate, and follow-up outcomes (modified Rankin Scale, mRS) of all the patients were retrospectively reviewed and collected. Multivariable logistic analysis was used to calculate potential risk factors for predicting poor outcomes (mRS ≥3). RESULTS: Of the 75 patients, 61 (81.3%) presented with initial hemorrhage, and 44 (58.7%) presented with 63 cerebral aneurysms. Immediate digital subtraction angiography (DSA) after the procedure showed complete occlusion of the cerebral aneurysms in all the patients, and total occlusion of the AVM nidus in 32/75 (42.7%) patients, 99-90% occlusion in 31/75 (41.3%) patients, and <90% occlusion in 12/75 (16.0%) patients. Favorable functional outcome (mRS <3) was achieved in 61 (81.3%) patients. After adjusting for other factors, multivariate logistic analysis showed that increasing patient age (OR, 1.086; 95% CI, 1.098-1.182), the size of AVM (OR, 9.072; 95% CI, 1.164-20.703), and eloquent location (OR, 9.209; 95% CI, 1.557-35.481) were significantly independent predictors of poor outcome. CONCLUSIONS: Endovascular treatment of cerebellar AVMs is safe and feasible. The high rate of associated cerebral aneurysms could explain the tendency of initial hemorrhage in cerebellar AVMs; targeted embolization of coexisting cerebral aneurysms should be the first priority. Increasing patient age, eloquent AVM location, and the size of AVM are independent predictors of poor outcome after endovascular treatment of cerebellar AVMs.