Terminal Function Research Articles

Improving the Performance of Polymer Solar Cells with Benzo[ghi]perylenetriimide-Based Small-Molecules as Interfacial Layers.

In this study, we prepared three benzo[ghi]perylenetriimide (BPTI) conjugated molecules as electron-transporting surface-modifying layers for polymer solar cells (PSCs). These three BPTI derivatives differed in the nature of their terminal functionalities, featuring butylamine (C3NH2), propylammonium iodide (C3NH3I), and butyldimethylamine (C3DMA) units, respectively. We evaluated the optoelectronic properties of PTB7-Th: PC71BM blends modified with these interfacial layers, as well as the performance of resulting PSCs. We used UV–Vis spectroscopy, atomic force microscopy, surface energy analysis, ultraviolet photoelectron spectroscopy, and photoelectric flow measurements to examine the phenomena behind the changes in the optoelectronic behavior of these blend films. The presence of a BPTI derivative changed the energy band alignment at the ZnO–active layer interface, leading to the ZnO film behaving more efficiently as an electron-extraction electrode. Modifying the ZnO surface with the BPTI-C3NH3I derivative resulted in a best power conversion efficiency (PCE) of 10.2 ± 0.53% for the PTB7-Th:PC71BM PSC (cf. PCE of the control device of 9.1 ± 0.13%). In addition, modification of a PM6:Y6:PCBM PSC with the BPTI-C3NH3I derivative increased its PCE from 15.6 ± 0.25% to 16.5 ± 0.18%. Thus, BPTI derivatives appear to have potential as IFLs when developing high-performance PSCs, and might also be applicable in other optoelectronic devices.

Ambiguity tube MPC

This paper is about a class of distributionally robust model predictive controllers (MPC) for nonlinear stochastic processes, which evaluate risk and control performance measures by propagating ambiguity sets in the space of state probability measures. A framework for formulating such ambiguity tube MPC controllers is presented using methods from the field of optimal transport theory. Moreover, an analysis technique based on supermartingales is proposed, leading to stochastic stability results for a large class of distributionally robust controllers. In this context, we also discuss how to construct terminal cost functions for stochastic and distributionally robust MPC that ensure closed-loop stability and asymptotic convergence to robust invariant sets. The corresponding theoretical developments are illustrated by tutorial-style examples and a numerical case study.

Chain Transfer Approach for Terminal Functionalization of Alternating Copolymerization of CO2 and Epoxide by Using Active Methylene Compounds as Chain Transfer Agents

Chain Transfer Approach for Terminal Functionalization of Alternating Copolymerization of CO₂ and Epoxide by Using Active Methylene Compounds as Chain Transfer Agents

Rational Optimization of Bifunctional Organoboron Catalysts for Versatile Polyethers via Ring-Opening Polymerization of Epoxides

Quaternary ammonium and phosphonium borane bifunctional catalysts have shown high catalytic performance in ring-opening polymerization (ROP) of epoxides to produce polyether. Herein, we systematically investigate a series of well-defined organoboron catalysts by varying the electronic and steric properties of the Lewis acidic boron (B) centers, manipulating the steric hindrance on the ammonium cation (N+), adjusting the distance between B and N+, and regulating the nucleic B number of the catalysts. The investigation on the dinuclear catalysts indicated that the reactivity of a given catalyst could be speculated by its B–N–B angle and the B···B distance. We found that the increase of Lewis acidity and the number of B centers of the organoboron catalysts are useful for a high catalytic activity for ROP of epoxides. The Lewis acidity of the B centers was determined using the acceptor numbers, showing an order of borinane (23.4) > BBN (21.7) > BCy2 (18.8) > Bpin (15.5). Moreover, we demonstrated the production of various telechelic polyols in the presence of different chain transfer agents using the organoboron catalysts. The produced telechelic samples have a well-defined terminal functionality with controllable molecular weight. Lastly, these organoboron catalysts were utilized to produce block copolymers, allyl-terminated macromonomers, and random copolymers.

A metal alkynyl molecular wire with PN ligands: Synthesis, isomerization, physical properties and single-molecule conductance

As new candidates for organometallic molecular wires, we designed a ruthenium trans-di(alkynyl) molecular wire 1H, trans-Ru(PN)2(C≡CC≡C-H)2, with the two mixed phosphine-pyridine supporting ligands (PN: 2-diphenylphosphinomethyl-6-methylpyridine). While two stereo-isomers with the syn and anti configurations were possible, the syn isomers of triisopropylsilylbutadiynyl precursors syn-1TIPS and syn-1H were prepared in direct and stereo-selective manners. Electrochemical analysis of syn-1TIPS revealed a virtually reversible redox wave with the potential cathodically shifted compared to that of the bis(diphosphine) analogue 2TMS, trans-Ru(dppe)2(C≡CC≡C-SiMe3)2. The density functional theoretical (DFT) study supports the similarity of the electronic structures of 1 and 2 with the HOMOs being close to the Fermi energy level of gold electrodes. STM-break junction measurements of Au-syn-1-Au (Au: gold electrode) revealed high single-molecule conductance (1.9 × 10–2G0), which is comparable to that of Au-2-Au. Calculations on the basis of the DFT-non equilibrium Green’s function method also support the experimental results. Notably, the molecular junction Au- syn-1-Au can be formed from syn-1H through C-H activation and formation of Au-C bonds without any pre-functionalization in contrast to the bis(diphosphine) analogue 2H, which requires terminal gold functionalization.

Polybutadiene derived allophanate as the crosslinker for Diels–Alder type self‐healing polyurethane networks

AbstractIntrinsic self‐healing materials have drawn great interest in recent years. The design of novel building blocks is essential for developing polymer networks with different properties. Allophanate is usually regarded as a side product during the preparation of polyurethanes. During the research of self‐healing polyurethane networks, we have studied the terminal functionalization of hydroxyl‐terminated polybutadiene with furfuryl isocyanate and occasionally obtained the furan‐terminated polybutadiene allophanate. The tetra‐branched molecule is employed as the crosslinker in the construction of a series of Diels–Alder type polyurethane networks. These polyurethane networks exhibit good mechanical performance and excellent self‐healing ability. Damages can be healed via the thermo‐promoted dissociation and recombination cycle, giving good to excellent recovery of tensile strength within three cycles of “damage‐repair” processes.

Improvement of charge mobility and photovoltaic performance of small molecule oligothiophene donors through self-assembly

Through molecular engineering of cyanopyridone functionality, herein, two new, small molecule oligothiophene donors, coded as CP7 and CP8, are reported which were designed, synthetically developed, and used in solution-processed bulk-heterojunction devices with the conventional acceptor, PC61BM. Both CP7 and CP8 comprise a common donor, i.e., triphenylamine, a common π-linker, i.e., bis-thiophene, and a cyanopyridone electron accepting group with different substituents at the nitrogen atom of cyanopyridone functionality. The presence of terminal acid group helped to achieve self-assembly of CP7 via hydrogen bonding, and as a result, its pristine and blend film morphologies were superior when compared with the film morphologies based on CP8 (donor oligothiophene comprising terminal ester functionality), thus, affording better device outcome (8.12% (CP7) vs 5.40% (CP8)). The results demonstrated that the molecular engineering of cyanopyridone-based oligothiophene donors to induce self-assembly and to improve film morphology was a key factor for the enhancement of photovoltaic performance. That being said, the power conversion efficiency of >8% is the highest efficiency number reported in the current literature for cyanopyridone-based small molecule oligothiophene donors.

End Group Functionality of 95-99%: Epoxide Functionalization of Polystyryl-Lithium Evaluated via Solvent Gradient Interaction Chromatography.

End group functionality is a key parameter of functional polymer chains. The end-capping efficiency of living polystyryl lithium with various epoxides, namely ethylene oxide (EO), ethoxy ethyl glycidyl ether (EEGE) and isopropylidene glyceryl glycidyl ether (IGG), is investigated with solvent gradient interaction chromatography (SGIC). Generally, end-capping efficiencies >95% are observed. Hydroxy functional polystyrene (PS-OH, PS-EEGE-OH, and PS-IGG-OH) with molar masses ranging from 13.8 to 15.0kgmol-1 are obtained, with dispersities of 1.05-1.06. Deprotection of the acetal (PS-EEGE-OH) and ketal protective group (PS-IGG-OH) is investigated. Nearly quantitative deprotection (>99%) resulting in the corresponding multihydroxy functional PS (PS-(OH)2 and PS-(OH)3 ) are observed via SGIC. Esterification of PS-OH with succinic anhydride shows a conversion of 98% to the corresponding ester. A detailed picture of side reactions during the carbanionic polymer synthesis subsequent epoxide termination is obtained, demonstrating 95-99% terminal functionality. Depending on the polarity of the end group, an elution order of PS-OH<PS-(OH)2 <PS-(OH)3 <PS-COOH is obtained in SGIC. The study demonstrates both the analytical power of SGIC and the exceptionally high terminal functionalization efficiency of anionic polymerization methods.

Effect of different molecular weight and terminal group PLGA on docetaxel nanoparticles: characterization and cytotoxic activity of castration-resistant prostate cancer cells

The choice of polymer and its compatibility with drug used determine the fate of nanoparticle in therapy. There has been limited sources about effect of resomer differentiation in nanoparticle related with physical and chemical properties and also biological activities of product. Therefore, we aimed to formulate docetaxel-loaded polylactic-co-glycolic acid nanoparticles with different molecular weights (Resomer 502 and 504) and terminal groups (Resomer 502H and 504H) and to investigate the effect of these resomers on nanoparticle character, prostate cancer, and healthy cells. Docetaxel-loaded PLGA nanoparticles were prepared by single emulsion solvent evaporation method. Surface characterizations were carried out by zeta sizer and scanning electron microscopy. Encapsulation efficiency, in vitro drug release profiles, and cytotoxic activity were determined. Main effect on the surface morphology of nanoparticles was the molecular weight of the polymer. The groups with acid terminal function have higher encapsulation and reaction efficiency. In all formulations, in vitro release was observed after 334 h at pH 7.4 and 240 h at pH 5.6. Also, the groups with high molecular weight showed selective cytotoxicity. These resomers especially RG 504 and RG 504H have potential to be used as a low-dose and high-efficiency extended-release drug delivery system in the treatment of prostate cancer.

Specific Bifunctionalization on the Surface of Phosphorus Dendrimers Syntheses and Properties

Dendrimers are highly branched macromolecules possessing, in most cases, identical terminal functions. However, it is sometimes desirable to have two types of surface functions in order to fulfil specific properties. The stochastic functionalization is frequently used for such purposes, but the presence of an uncontrolled number of each type of terminal function, albeit acceptable for research purposes, has no practical use. Thus, it is highly desirable to find strategies suitable for the precise grafting of two different functional groups on the surface of dendrimers. The easiest way, and the most widely used, consists in using a bifunctional monomer to be grafted to all of the surface functions of the dendrimers. Two other strategies are known but are rarely used: the modification of an existing function, to generate two functions, and the sequential grafting of one function then of a second function. The three methods are illustrated in this review with polyphosphorhydrazone (PPH) dendrimers, together with their properties as catalysts, for materials, and as biological tools.

Altered Accumbal Dopamine Terminal Dynamics Following Chronic Heroin Self-Administration.

Administration of heroin results in the engagement of multiple brain regions and the rewarding and addictive effects are mediated, at least partially, through activation of the mesolimbic dopamine system. However, less is known about dopamine system function following chronic exposure to heroin. Withdrawal from chronic heroin exposure is likely to drive a state of low dopamine in the nucleus accumbens (NAc), as previously observed during withdrawal from other drug classes. Thus, we aimed to investigate alterations in NAc dopamine terminal function following chronic heroin self-administration to identify a mechanism for dopaminergic adaptations. Adult male Long Evans rats were trained to self-administer heroin (0.05 mg/kg/inf, IV) and then placed on a long access (FR1, 6-h, unlimited inf, 0.05 mg/kg/inf) protocol to induce escalation of intake. Following heroin self-administration, rats had decreased basal extracellular levels of dopamine and blunted dopamine response following a heroin challenge (0.1 mg/kg/inf, IV) in the NAc compared to saline controls. FSCV revealed that heroin-exposed rats exhibited reduced stimulated dopamine release during tonic-like, single-pulse stimulations, but increased phasic-like dopamine release during multi-pulse stimulation trains (5 pulses, 5–100 Hz) in addition to an altered dynamic range of release stimulation intensities when compared to controls. Further, we found that presynaptic D3 autoreceptor and kappa-opioid receptor agonist responsivity were increased following heroin self-administration. These results reveal a marked low dopamine state following heroin exposure and suggest the combination of altered dopamine release dynamics may contribute to increased heroin seeking.

Modeling the Truck Appointment System as a Multi-Player Game

Background: Random truck arrivals at maritime container terminals are one of the primary reasons for gate congestion. Gate congestion negatively affects the terminal’s and drayage firms’ productivity and the surrounding communities in terms of air pollution and noise. To alleviate gate congestion, more and more terminals in the USA are utilizing a truck appointment system (TAS). Methods: This paper proposes a novel approach to modeling the truck appointment system problem. Unlike previous studies which largely treated this problem as a single-player game, this study explicitly models the interplay between the terminal and drayage firms with regard to appointments. A multi-player bi-level programming model is proposed, where the terminal functions as the leader at the upper-level and the drayage firms function as followers at the lower-level. The objective of the leader (the terminal) is to minimize the gate waiting cost of trucks by spreading out the truck arrivals, and the objective of the followers (drayage firms) is to minimize their own drayage cost. To make the model tractable, the bi-level model is transformed to a single-level problem by replacing the lower-level problem with its equivalent Karush–Kuhn–Tucker (KKT) conditions and the model is solved by finding the Stackelberg equilibrium in one-shot simultaneous-moves among players. For comparison purposes, a single-player version of the TAS model is also developed. Results: Experimental results indicate that the proposed multi-player model yields a lower gate-waiting cost compared to the single-player model, and that it yields higher cost savings for the drayage firms as the number of appointments per truck increases. Moreover, the solution of the multi-player model is not dependent on the objective function coefficients, unlike the single player model. Conclusions: This study demonstrates that a TAS is more effective if it considers how the assigned appointment slot affects a truck’s drayage cost. It is recommended that terminal operators and port authorities initiate conversations with their TAS providers about incorporating this element into their TAS.

Template and Temperature-Controlled Polymorph Formation in Squaraine Thin Films.

Controlling the polymorph formation in organic semiconductor thin films by the choice of processing parameters is a key factor for targeted device performance. Small molecular semiconductors such as the prototypical anilino squaraine compound with branched butyl chains as terminal functionalization (SQIB) allow both solution and vapor phase deposition methods. SQIB has been considered for various photovoltaic applications mainly as amorphous isotropic thin films due to its broad absorption within the visible to deep-red spectral range. The two known crystalline polymorphs adopting a monoclinic and orthorhombic crystal phase show characteristic Frenkel excitonic spectral signatures of overall H-type and J-type aggregates, respectively, with additional pronounced Davydov splitting. This gives a recognizable polarized optical response of crystalline thin films suitable for identification of the polymorphs. Both phases emerge with a strongly preferred out-of-plane and rather random in-plane orientation in spin-casted thin films depending on subsequent thermal annealing. By contrast, upon vapor deposition on dielectric and conductive substrates, such as silicon dioxide, potassium chloride, graphene, and gold, the polymorph expression depends basically on the choice of growth substrate. The same pronounced out-of-plane orientation is adopted in all crystalline cases, but with a surface templated in-plane alignment in case of crystalline substrates. Strikingly, the amorphous isotropic thin films obtained by vapor deposition cannot be crystallized by thermal postannealing, which is a key feature for the spin-casted thin films, here monitored by polarized in situ microscopy. Combining X-ray diffraction, atomic force microscopy, ellipsometry, and polarized spectro-microscopy, we identify the processing-dependent evolution of the crystal phases, correlating morphology and molecular orientations within the textured SQIB films.

Ditelluride, Terminal Tellurido, and Bis(tellurido) Motifs of Titanium.

Highly modular and rational syntheses of titanium compounds containing ditelluride, terminal telluride, and bis(telluride) structural motifs are disclosed in this study. Titanate anions bearing two cis and terminal telluride functionalities bound to the same metal center represent a unique example of a group 4 transition metal bis(chalcogenide) ion and are accessed in a simple, single-step procedure from Ti(III) bis(alkyl) complexes in the presence of an outer-sphere reductant and at least 3 equiv of Te0 powder. These compounds have been characterized crystallographically and spectroscopically with some preliminary reactivity reported for the anionic Ti(═Te)2 motif. We also report solution 125Te NMR spectral data in addition to theoretical studies addressing the bonding and structure for these titanate bis(tellurido) systems.

Robust MPC for LPV systems via a novel optimization-based constraint tightening

We propose a novel approach to design a robust Model Predictive Controller (MPC) for constrained uncertain linear systems. The uncertain system is modeled as linear parameter varying with an additive disturbance. Set bounds for the system matrices and the additive uncertainty are assumed to be known. We formulate a novel optimization-based constraint tightening strategy around a predicted nominal trajectory which utilizes these bounds. With an appropriately designed terminal cost function and constraint set, we prove robust satisfaction of the imposed constraints by the resulting MPC in closed-loop with the uncertain system, and Input to State Stability of the origin. We highlight the efficacy of our proposed approach via a numerical example.

Surface modification of glass fiber membrane via insertion of a bis(diarylcarbene) assisted with polymerization and cross-linking reactions

Glass Fiber (GF) membrane was modified using bis(diaryldiazomethane) derivatives with various terminal functionalities and characterized via multiple techniques including SEM, XPS, ATR-IR, proving successful modification and offering an alternative route to surface-modified glass materials. Significant changes in surface wetting were observed by successive functionalization of the GF surface. Surface modification was proposed to proceed through two independent mechanisms, the first being insertion via carbene into surface X-H (Si-O-H) bonds, while the second is polymerization by propagation of the carbene with active surface terminal amine functions; this is the first time that carbene-mediated polymerization at a modified surface has been identified. This latter process proceeds without catalysis by transition metals, and leads to encapsulation of the glass fibres. This approach is complementary to traditional silane coupling reagents, producing bis(diarylcarbene) (in short, biscarbene)-modified GF membrane in which surface physical and chemical properties have been modified independently of the bulk.

Controllable Polymerization of N -Substituted β-Alanine N -Thiocarboxyanhydrides for Convenient Synthesis of Functional Poly(β-peptoid)s

Controllable Polymerization of <i>N</i> -Substituted β-Alanine <i>N</i> -Thiocarboxyanhydrides for Convenient Synthesis of Functional Poly(β-peptoid)s

A Compound Control Method Based on the Adaptive Linear Extended State Observer and Global Fast Terminal Sliding Mode Control for Inertially Stabilized Platform

To realize high-performance control for the inertially stabilized platform, a compound control method based on the adaptive linear extended state observer and global fast terminal sliding mode control is proposed. For estimating the unknown disturbances of inertially stabilized platform, an adaptive linear extended state observer was developed. With the full use of the information of attitude and angular velocity, the adaptive bandwidth of an adaptive linear extended state observer can deal with the peaking phenomenon without introducing excessive noise. Furthermore, the adaptation law based on the global fast terminal sliding mode control for disturbance estimation compensation was developed, which can improve the disturbance estimation accuracy of the adaptive linear extended state observer, and the higher order terminal function in global fast terminal sliding mode control was replaced by the lumped disturbance estimation of adaptive linear extended state observer, which can improve the anti-interference ability of inertially stabilized platform, reduce the chattering problem, and improve the control performance. The asymptotic stability of the proposed control method has been proven by the Lyapunov stability theory. The effectiveness of the proposed method was validated by a series of simulations and experiments.

Nonutilization of Kidneys From Donors After Circulatory Determinant of Death.

Background.The expansion of donation after circulatory determination of death (DCDD) programs and unmet demands for kidney transplantation indicate that there is a need to improve the efficiency and utilization of these organs.Methods.We studied all DCDD donors retrieved for kidney transplantation in Australia between 2014 and 2019 and determined the factors associated with nonutilization using least absolute shrinkage and selection operator and random forest models. Self-organizing maps were used to group these donors into clusters with similar characteristics and features associated with nonutilization were defined.Results.Of the 762 DCDD donors, 116 (15%) were not utilized for kidney transplantation. Of the 9 clusters derived from self-organizing map, 2 had the highest proportions of nonutilized kidneys. Factors for nonutilization (adjusted odds ratio [95% confidence interval], per SD increase) were duration from withdrawal of cardiorespiratory support till death (1.38 [1.16-1.64]), admission and terminal serum creatinine (1.43 [1.13-1.85]) and (1.41 [1.16-1.73]). Donor kidney function and duration of warm ischemia were the main factors for clinical decisions taken not to use kidneys from DCDD donors.Conclusions.Donor terminal kidney function and the duration of warm ischemia are the key factors for nonutilization of DCDD kidneys. Strategies to reduce the duration of warm ischemia and improve post-transplant recipient kidney function may reduce rates of nonutilization.

Spontaneous partial recovery of striatal dopaminergic uptake despite nigral cell loss in asymptomatic MPTP-lesioned female minipigs

The Göttingen minipig is a large animal with a gyrencephalic brain that expresses –complex behavior, making it an attractive model for Parkinson’s disease research. Here, we investigate the temporal evolution of presynaptic dopaminergic function for 14 months after injections of 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into the minipig using a multi-tracer longitudinal positron emission tomography (PET) design. We injected seven sedated minipigs with 1–2 mg/kg of MPTP, and two with saline, three times a week over four weeks. We monitored behavioral deficits using a validated motor scale and walking mat. Brains were imaged with (+)-⍺-[11C]-dihydrotetrabenazine ([11C]-DTBZ) and [18F]-dihydroxyphenylalanine ([18F]-FDOPA) PET at baseline and 1, 3, 10 and 14 months after MPTP injection, and immunohistochemistry was used to assess nigral cell loss. The minipigs showed mild bradykinesia and impaired coordination at early timepoints after MPTP. PET revealed decreases of striatal [11C]-DTBZ and [18F]-FDOPA uptake post-MPTP with partial spontaneous recovery of [18F]-FDOPA after 10 months. Postmortem analysis estimated an MPTP-induced nigral loss of 57% tyrosine hydroxylase+ and 43% Nissl-stained cells. Normal motor function despite substantial damage to the dopaminergic system is consistent with prodromal Parkinson’s disease, and offers an opportunity for testing disease-modifying therapies. However, partial spontaneous recovery of dopamine terminal function must be taken into account in future studies.