Combinatorial System Research Articles

Toggling Independent Sets of a Path Graph

This paper explores the orbit structure and homomesy (constant averages over orbits) properties of certain actions of toggle groups on the collection of independent sets of a path graph. In particular we prove a generalization of a homomesy conjecture of Propp that for the action of a "Coxeter element" of vertex toggles, the difference of indicator functions of symmetrically-located vertices is 0-mesic. Then we use our analysis to show facts about orbit sizes that are easy to conjecture but nontrivial to prove. Besides its intrinsic interest, this particular combinatorial dynamical system is valuable in providing an interesting example of (a) homomesy in a context where large orbit sizes make a cyclic sieving phenomenon unlikely to exist, (b) the use of Coxeter theory to greatly generalize the set of actions for which results hold, and (c) the usefulness of Striker's notion of generalized toggle groups.

An Efficient Itemset Representation for Mining Frequent Patterns in Transactional Databases

In this paper we propose very efficient itemset representation for frequent itemset mining from transactional databases. The combinatorial number system is used to uniquely represent frequent k-itemset with just one integer value, for any k ≥ 2. Experiments show that memory requirements can be reduced up to 300 %, especially for very low minimal support thresholds. Further, we exploit combinatorial number schema for representing candidate itemsets during iterative join-based approach. The novel algorithm maintains one-dimensional array rank, starting from k = 2nd iteration. At the index r of the array, the proposed algorithm stores unique integer representation of the r-th candidate in lexicographic order. The rank array provides joining of two candidate k-itemsets to be O(1) instead of O(k) operation. Additionally, the rank array provides faster determination which candidates are contained in the given transaction during the support count and test phase. Finally, we believe that itemset ranking by combinatorial number system can be effectively integrated into pattern-growth algorithms, that are state-of-the-art in frequent itemset mining, and additionally improve their performances.

On the -oo Suffix of Campbell’s Monkeys

Ouattara et al. (2009a,b) make the novel claim that Campbell’s monkey alarm calls demonstrate a simple pattern of linguistic morphology. The authors observe that there are at least two distinct alarm calls (called krak and hok) that are used in two different predatory contexts, and that each may be followed by a low frequency sound (called -oo) that alters the meaning of both calls in predictable ways, allowing contexts with reduced level of threat. In light of these facts, -oo is analyzed as a meaning-bearing, combinatorial unit. However, the claim that a non-human communication system has a combinatorial system (however primitive) is rare in the literature (see x5 for related patterns), and, indeed, is antithetical to certain claims that structural hierarchy is unique to human language (e.g., Bolhuis et al. 2014). Moreover, it has been noted (Schlenker et al. 2014) that there is redundancy between the apparent semantic contribution of -oo and the semantic contribution of a variety of other signal manipulations (e.g. calling rate) that are easiest to explain via non-compositional mechanisms. These facts warrant particular caution when evaluating the pattern as a possible counterexample to generalizations about human language. Thus, in this squib, we examine the compositional hypothesis further. As counterpoint, we consider a class of more conservative hypotheses in which -oo does not itself bear meaning, but instead arises as the side effect of other articulatory processes that noncompositionally affect call meaning. Key to such hypotheses is the premise that -oo is articulatorily parasitic on another phonetic process. A major contribution of this squib is thus phonetic: considering the acoustic properties of -oo, we conclude that complex calls (krakoo and hokoo) are produced with a two pulses of a single breath-group. Critically, the production of these complex calls requires an additional articulatory gesture and thus an increase in articulatory effort. An increase in articulatory effort would not be expected on an analysis in which -oo arises as a phonetic side effect; we accordingly reject these alternate hypotheses, thus strengthening the robustness of the combinatorial analysis.

OPTIMAL ROUTE DETECTION BETWEEN EDUCATIONAL INSTITUTIONS OF REZEKNE MUNICIPALITY

Information about the merger of schools or their optimization periodically appears in the society. It is believed that the ideal school network is not yet ready. The paper provides the analysis of the educational institutions locations by their availability. A theoretical research has been conducted and mathematically the shortest path has been calculated between different educational institutions. The paper also provides mapping of these educational institutions and location analysis of educational institutions at different levels. The main goal of the paper is to show the possibilities of applying the mathematical models in solving practical tasks – to determine the shortest path between the educational institutions. This study describes an optimization method called Simulated Annealing. The Simulated Annealing method is widely used in various combinatorial optimization tasks. Simulated Annealing is a stochastic optimization method that can be used to minimize the specified cost function given a combinatorial system with multiple degrees of freedom. In this paper the application of Travelling Salesman Problem, is demonstrated and an experiment aimed to find the shortest route between educational institutions of Rezekne Municipality is performed. It gives possibilities to analyse and search optimal school' s network in the Rezekne Municipality. Common research methods are used in this research: descriptive research method, statistical method, mathematical modelling

Application of super-sticking algebraic operation of variables for Boolean functions minimization by combinatorial method

The simplification of the problem of Boolean function minimization by a combinatorial method is a new procedure for the algebra of logic – super-sticking of variables. This procedure is performed if there is a complete binary combinatorial system with repetition or an incomplete binary combinatorial system with repetition in the truth table structure. The procedure for reducing the total perfect disjunctive normal form (PDNF) of the logical function gives unity. And since the complete PDNF uniquely determines the complete binary combinatorial system with repetition and vice versa, this gives grounds to delete all the blocks of the complete binary combinatorial system from the truth table, whose structure allows to carry out the rules of super-sticking of variables. The efficiency of the algebraic operation of supers-sticking of variables greatly simplifies the algorithm for Boolean function minimization and allows manual minimization of functions with a number of variables up to 10. The complexity of the algorithm for finding the minimal function by a combinatorial method is O(n) and is linear for n<7. With an increase in the number of variables from n=6 to 8, the growth dynamics of the number of transformations is characterized by the law O(n 2 ), followed by the growth of O(f(n)) with the increase in the Boolean function capacity according to the polynomial law. The introduction of an algebraic operation of super-sticking of variables to the problem of Boolean function minimization is more advantageous in comparison with analogs in the following factors: – lower cost of development and implementation, since a significant proportion of functions are minimized by functions with a number of variables of no more than 16, and therefore, in general, the need for automation of the process of minimizing the function decreases; – increase in manual minimization of 4–10 bit functions, facilitates control and study of the algorithm for minimizing the logic function. The combinatorial method of Boolean functions minimization can find practical application in the design of electronic computer systems, because: – minimization of the DNF function is one of the multiextremal logic-combinatorial problems, the solution of which is, in particular, the combinatorial device of the block-diagram with repetition; – extends the capabilities of the algorithm for Boolean functions minimization for their application in information technology; – improves the algebraic method of Boolean function minimization due to the tabular organization of the method, the introduction of the shaped transformation apparatus and the rules of super-sticking of variables.

High-throughput combinatorial chemical bath deposition: The case of doping Cu (In, Ga) Se film with antimony

The conventional methods for designing and preparing thin film based on wet process remain a challenge due to disadvantages such as time-consuming and ineffective, which hinders the development of novel materials. Herein, we present a high-throughput combinatorial technique for continuous thin film preparation relied on chemical bath deposition (CBD). The method is ideally used to prepare high-throughput combinatorial material library with low decomposition temperatures and high water- or oxygen-sensitivity at relatively high-temperature. To check this system, a Cu(In, Ga)Se (CIGS) thin films library doped with 0–19.04 at.% of antimony (Sb) was taken as an example to evaluate the regulation of varying Sb doping concentration on the grain growth, structure, morphology and electrical properties of CIGS thin film systemically. Combined with the Energy Dispersive Spectrometer (EDS), X-ray Photoelectron Spectroscopy (XPS), automated X-ray Diffraction (XRD) for rapid screening and Localized Electrochemical Impedance Spectroscopy (LEIS), it was confirmed that this combinatorial high-throughput system could be used to identify the composition with the optimal grain orientation growth, microstructure and electrical properties systematically, through accurately monitoring the doping content and material composition. According to the characterization results, a Sb2Se3 quasi-liquid phase promoted CIGS film-growth model has been put forward. In addition to CIGS thin film reported here, the combinatorial CBD also could be applied to the high-throughput screening of other sulfide thin film material systems.

Functional Prioritization and Hydrogel Regulation Phenomena Created by a Combinatorial Pearl-Associated Two-Protein Biomineralization Model System.

In the nacre or aragonitic layer of an oyster pearl, there exists a 12-member proteome that regulates both the early stages of nucleation and nanoscale-to-mesoscale assembly of nacre tablets and calcitic crystals from mineral nanoparticle precursors. Several approaches to understanding protein-associated mechanisms of pearl nacre formation have been developed, yet we still lack insight into how protein ensembles or proteomes manage nucleation and crystal growth. To provide additional insights, we have created a proportionally defined combinatorial model consisting of two pearl nacre-associated proteins, PFMG1 and PFMG2 (shell oyster pearl nacre, Pinctada fucata) whose individual in vitro mineralization functionalities are distinct from one another. Using scanning electron microscopy, atomic force microscopy, Ca(II) potentiometric titrations, and quartz crystal microbalance with dissipation monitoring quantitative analyses, we find that at 1:1 molar ratios, rPFMG2 and rPFMG1 co-aggregate in specific molecular ratios to form hybrid hydrogels that affect both the early and later stages of in vitro calcium carbonate nucleation. Within these hybrid hydrogels, rPFMG2 plays a role in defining protein co-aggregation and hydrogel dimension, whereas rPFMG1 defines participation in nonclassical nucleation processes; both proteins exhibit synergy with regard to surface and subsurface modifications to existing crystals. The interactions between both proteins are enhanced by Ca(II) ions and may involve Ca(II)-induced conformational events within the EF-hand rPFMG1 protein, as well as putative interactions between the EF-hand domain of rPFMG1 and the calponin-like domain of rPFMG2. Thus, the pearl-associated PFMG1 and PFMG2 proteins interact and exhibit mineralization functionalities in specific ways, which may be relevant for pearl formation.

Abstract 3755: Renewable and genetically engineered natural killer cells for off-the-shelf adoptive cellular immunotherapy

Abstract The unique attributes of a combinatorial tumor recognition system, diminished off-tumor cytotoxicity, and multifaceted effector function make natural killer (NK) cells a prime candidate for a universal approach to cancer immunotherapy. In addition, NK cells are the principal mediator of antibody-directed cellular cytotoxicity (ADCC). However, NK cell function is often impaired in the setting of cancer, reducing the effectiveness of the endogenous immune system and the therapeutic efficacy of monoclonal antibodies. To address the need for advanced and combinatorial cancer therapies, we developed a unique and effective strategy to create a renewable source of engineered “off-the-shelf” NK cells with augmented function, including enhanced ADCC and persistence. Key challenges associated with genetic editing, limited expansion, persistence and variability of peripheral blood (PB)-derived NK cells were overcome by utilizing our induced pluripotent stem cell (iPSC) technology as the unlimited starting material for the reproducible and consistent derivation of engineered NK cells. Through targeted transgene integration, we produced a clonal iPSC master cell line to continuously produce NK cells engineered to uniformly express a high affinity, non-cleavable version of CD16 (hnCD16-NK). In directed differentiation, the hnCD16-NK cells displayed homogeneous expression of CD16 (&amp;gt;95%) and a mature CD56+ NK cell phenotype, as exhibited by expression of KIR, NCRs, DNAM-1, and NKG2D. In contrast to endogenous CD16 expression, the engineered hnCD16 molecule was shown to be cleavage resistant upon NK cell activation (&amp;gt;95% CD16+ hnCD16-NK vs. &amp;lt;10% CD16+ PB-derived NK cell, upon target cell-mediated activation), and demonstrated enhanced antibody binding compared to PB-derived NK cells expressing the low-affinity variant. In addition to increased expression of the cytolytic molecules perforin and granzyme B and enhanced direct cytotoxicity against tumor targets, hnCD16-NK cells displayed superior ADCC capacity and cytokine production in response to CD16 stimulation. Importantly, manufacture of hnCD16-NK cells was proven to be highly scalable, delivering up to 107 fold expansion over a 35 day period. The maintained proliferative capacity can be in part associated with longer telomere length seen in hnCD16-NK cells. Furthermore, deletion of classical human leukocyte antigen molecules and ectopic expression of immunosuppressive proteins engineered at the iPSC level provided the ability of hnCD16-NK cells to potentially overcome the host histocompatibility barrier and to improve persistence in the allogeneic setting. In conclusion, the preclinical data presented herein highlight the therapeutic value of hnCD16-iNK cells as an ideal ADCC-mediated “off-the-shelf” NK cell-based immunotherapeutic product with augmented persistence, anti-tumor capacity, manufacturing reliability and preclinical efficacy. Citation Format: Ryan Bjordahl, Frank Cichocki, Raedun Clarke, Svetlana Gaidarova, Brian Groff, Paul Rogers, Stacey Moreno, Ramzey Abujarour, Greg Bonello, Tom Lee, Weijie Lan, Matthieu Bauer, Dave Robbins, Betsy Rezner, Sarah Cooley, Bruce Walcheck, Stewart Abbot, Bruce Blazar, Scott Wolchko, Daniel Shoemaker, Jeffrey S. Miller, Bahram Valamehr. Renewable and genetically engineered natural killer cells for off-the-shelf adoptive cellular immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3755. doi:10.1158/1538-7445.AM2017-3755

An on-chip cell culturing and combinatorial drug screening system

A low-cost, convenient and precise drug combination screening microfluidic platform is developed, in which cell culture chambers designed with micropillars integrate with three laminar flow diffusion channels. This platform has several distinct features, including minimum shear stress on cells, biocompatibility, optimum concentration distribution and automatic combinatorial gradient generation, which can potentially speed up the discovery of an effective drug combination for cancer ablations. The presented device can generate two-drug combination gradients at the optimum flow rate of 90 μL/h and can be applied to identify the optimal combination of two clinically relevant chemotherapy drugs. For demonstration, paclitaxel at 0.77 × 10−3 mg/mL and cisplatin at 0.23 × 10−4 mg/mL were studied against lung cancer cells (A549). This microfluidic device has the potential to provide a precise and robust screening for anticancer combinational drugs practiced in clinics.

Breeding novel solutions in the brain: a model of Darwinian neurodynamics.

Background: The fact that surplus connections and neurons are pruned during development is well established. We complement this selectionist picture by a proof-of-principle model of evolutionary search in the brain, that accounts for new variations in theory space. We present a model for Darwinian evolutionary search for candidate solutions in the brain. Methods: We combine known components of the brain - recurrent neural networks (acting as attractors), the action selection loop and implicit working memory - to provide the appropriate Darwinian architecture. We employ a population of attractor networks with palimpsest memory. The action selection loop is employed with winners-share-all dynamics to select for candidate solutions that are transiently stored in implicit working memory. Results: We document two processes: selection of stored solutions and evolutionary search for novel solutions. During the replication of candidate solutions attractor networks occasionally produce recombinant patterns, increasing variation on which selection can act. Combinatorial search acts on multiplying units (activity patterns) with hereditary variation and novel variants appear due to (i)noisy recall of patterns from the attractor networks, (ii)noise during transmission of candidate solutions as messages between networks, and, (iii)spontaneously generated, untrained patterns in spurious attractors. Conclusions: Attractor dynamics of recurrent neural networks can be used to model Darwinian search. The proposed architecture can be used for fast search among stored solutions (by selection) and for evolutionary search when novel candidate solutions are generated in successive iterations. Since all the suggested components are present in advanced nervous systems, we hypothesize that the brain could implement a truly evolutionary combinatorial search system, capable of generating novel variants.

Breeding novel solutions in the brain: a model of Darwinian neurodynamics

Background: The fact that surplus connections and neurons are pruned during development is well established. We complement this selectionist picture by a proof-of-principle model of evolutionary search in the brain, that accounts for new variations in theory space. We present a model for Darwinian evolutionary search for candidate solutions in the brain. Methods: We combine known components of the brain – recurrent neural networks (acting as attractors), the action selection loop and implicit working memory – to provide the appropriate Darwinian architecture. We employ a population of attractor networks with palimpsest memory. The action selection loop is employed with winners-share-all dynamics to select for candidate solutions that are transiently stored in implicit working memory. Results: We document two processes: selection of stored solutions and evolutionary search for novel solutions. During the replication of candidate solutions attractor networks occasionally produce recombinant patterns, increasing variation on which selection can act. Combinatorial search acts on multiplying units (activity patterns) with hereditary variation and novel variants appear due to (i) noisy recall of patterns from the attractor networks, (ii) noise during transmission of candidate solutions as messages between networks, and, (iii) spontaneously generated, untrained patterns in spurious attractors. Conclusions: Attractor dynamics of recurrent neural networks can be used to model Darwinian search. The proposed architecture can be used for fast search among stored solutions (by selection) and for evolutionary search when novel candidate solutions are generated in successive iterations. Since all the suggested components are present in advanced nervous systems, we hypothesize that the brain could implement a truly evolutionary combinatorial search system, capable of generating novel variants.

Person and number markers in Spanish verb forms

This article tests the claim that Spanish person and number markers are fused, hence impossible to separate. Traditional studies presume that number values cumulate in person markers, thus creating the portmanteau PN. While agreeing that number values lack their own markers, a few analyses depart from cumulation. They conflate person and number into an overarching category, which entails that there will be a single marker for them. The merit of conflation is that, by using a combinatorial system of persons to compose the values of the overarching category, it finds a means to deal with heterogeneous referentiality, a concomitant effect of pluralization. On close scrutiny, however, neither approach proves satisfactory. Cumulation leads to fictitious constructs and conflation fails to explain why pluralization affects referentiality. The alternative put forth corresponds to the third logical option: segregation. Person and number markers can be disentangled when one recognizes that, alongside monoexponence, there are alternative modes of structural-coding (i.e. nonexponence and polyexponence). The fact that pluralization induces heterogeneous referentiality is tied to deixis, which, in addition to requiring multiple elements, orders them with respect to the origo. This organization also sheds light on the relation between person and number and another grammatical category: clusivity.

SHORTEST PATH DETERMINATION BETWEEN EDUCATIONAL INSTITUTIONS OF RĒZEKNE MUNICIPALITY

This study describes an optimization method called Simulated Annealing. The Simulated Annealing method is widely used in various combinatorial optimization tasks. Simulated Annealing is a stochastic optimization method that can be used to minimize the specified cost function given a combinatorial system with multiple degrees of freedom. In this study the application of the Simulated Annealing method to a well - known task of combinatorial analysis, Travelling Salesman Problem, is demonstrated and an experiment aimed to find the shortest tour distances between educational institutions of Rēzekne Municipality is performed. It gives possibilities to analyze and search optimal schools' network in Rēzekne Municipality.

Nitrogen transformation under different dissolved oxygen levels by the anoxygenic phototrophic bacterium Marichromatium gracile.

Marichromatium gracile: YL28 (M. gracile YL28) is an anoxygenic phototrophic bacterial strain that utilizes ammonia, nitrate, or nitrite as its sole nitrogen source during growth. In this study, we investigated the removal and transformation of ammonium, nitrate, and nitrite by M. gracile YL28 grown in a combinatorial culture system of sodium acetate-ammonium, sodium acetate-nitrate and sodium acetate-nitrite in response to different initial dissolved oxygen (DO) levels. In the sodium acetate-ammonium system under aerobic conditions (initial DO = 7.20-7.25mg/L), we detected a continuous accumulation of nitrate and nitrite. However, under semi-anaerobic conditions (initial DO = 4.08-4.26mg/L), we observed a temporary accumulation of nitrate and nitrite. Interestingly, under anaerobic conditions (initial DO = 0.36-0.67mg/L), there was little accumulation of nitrate and nitrite, but an increase in nitrous oxide production. In the sodium acetate-nitrite system, nitrite levels declined slightly under aerobic conditions, and nitrite was completely removed under semi-anaerobic and anaerobic conditions. In addition, M. gracile YL28 was able to grow using nitrite as the sole nitrogen source in situations when nitrogen gas produced by denitrification was eliminated. Taken together, the data indicate that M. gracile YL28 performs simultaneous heterotrophic nitrification and denitrification at low-DO levels and uses nitrite as the sole nitrogen source for growth. Our study is the first to demonstrate that anoxygenic phototrophic bacteria perform heterotrophic ammonia-oxidization and denitrification under anaerobic conditions.

High Throughput Experimental Solutions for Solid State Lithium-Ion Battery Research

Breakthrough in lithium-ion battery technology is crucial for modern sustainable energy applications. Compared to conventional Lithium-ion battery with liquid electrolyte, solid state battery with solid ceramic electrolyte or polymer electrolyte possesses the advantages of higher working voltage, non-flammability, and lithium dendrite prevention [1, 2]. High-throughput methodologies, which enable rapid materials screening and rapid process optimization, are finding its applications in solid state Lithium-ion battery development. To support this high-throughput research, the experimental instrument must meet requirements such as maximizing productivity through parallel experiments and automation, compatibility with Ar gas glove box operation, high resistance to corrosion, and working with small amount of sample per experiment. MTI Corporation (Richmond CA, USA) strive to provide highly efficient and economical experimental equipment and solutions for high throughput battery development. In this work, MTI’s efforts on developing experimental instrumentations for high throughput research of solid state Lithium-ion battery are discussed. MTI’s high throughput experimental solution for solid state Lithium-ion battery is outlined in Fig. 1. First step is the solid electrolyte synthesis and preparation. MTI provides complete solution for ceramic powder synthesis, from solid / liquid dispensing, high throughput milling / mixing, to multi-channel heat processing with high throughput tube furnace. After the high throughput solid electrolyte powder synthesis, MTI’s 6-position, 10 ton max electric hydraulic press and 4-channel, 1” OD tube furnace up to 1700 ºC allow for a high throughput process of conventional sintering method. Novel sintering techniques, such as spark plasma sintering (SPS) [3] and hydrothermal-assisted cold sintering process (CSP) [4], are also supported by MTI’s instruments. These techniques, whether for the fast processing time of spark plasma sintering, or the low temperature processing capability of cold sintering process, open up possibilities of low cost, rapid fabrication of solid electrolytes, cathode pellets, or even the whole solid electrode-electrolyte stack [3]. Fast solid electrolyte material screening is possible with combinatorial deposition methods. Combinatorial sputtering deposition systems, which uses substrate mask and multiple deposition sources with adjustable tilt and power, are utilized to create compositional spreads and deposit ternary more complicated thin film composition libraries for ceramic electrolyte [5]. An example is MTI’s combinatorial magnetron sputtering system with 5 independent sputtering sources and rotatable 16-sample mask. Combinatorial spray pyrolysis allows rapid screening of ceramic-polymer composite electrolytes. With MTI’s 6-channel combinatorial ultrasonic spray pyrolysis system, various polymer hosts, liquid electrolytes, and ceramic solid electrolyte powder suspensions are concurrently pumped and mixed at different ratios, and sprayed onto the heated stage. By varying the ratio between polymer electrolyte and ceramic electrolyte, a balance between composite electrolyte‘s electrical and mechanical properties can be achieved through the high throughput screening [4, 6]. Second step is rapid composition characterization of the as-synthesized solid electrolyte powder using high throughput, automatic X-ray fluorescence (XRF) instrumentation. MTI’s 32-sample high throughput XRF spectrometer station integrates a compact XRF spectrometer and a high precision XYZ stage with an Ar gas glove box for quick and easy composition analysis from element Ne to Pu. Finally, the as-prepared solid electrolytes are assembled with electrodes in split cells for high throughput electrochemical testing. MTI’s 8-channel coin split cell kit allows for easy parallel comparison of multiple cells. Temperature dependent testing is of great interest as improved ionic conductivity is usually observed at elevated temperatures. Moreover, to ensure good interfacial contact between electrode and solid electrolyte, a sufficient compressive pressure needs to be applied on the split cell to confine the volume expansion during charge-discharge cycles [7]. In this effort, MTI has developed a battery dilatometer with adjustable compressive pressure, and a heatable lab press for electrochemical testing under controlled pressure and temperature. [1] Li J, Ma C, Chi M, Liang C, Dudney NJ. Adv. Energy Mater. 2015;5:1401408. [2] Kim JG, Son B, Mukherjee S, Schupper N, Bates A, Kwon O, et al. J. Power Sources 2015;282:299. [3] Kali R, Mukhopadhyay A. J. Power Sources 2014;247:920. [4] Guo J, Berbano SS, Guo H, Baker AL, Lanagan MT, Randall CA. Adv. Funct. Mater. 2016;26:7115. [5] Beal MS, Hayden BE, Le Gall T, Lee CE, Lu X, Mirsaneh M, et al. ACS Comb. Sci. 2011;13:375. [6] Zhao Y, Huang Z, Chen S, Chen B, Yang J, Zhang Q, et al. Solid State Ionics 2016;295:65. [7] Piper DM, Yersak TA, Lee SH. J. Electrochem. Soc. 2013;160:A77. Fig. 1. MTI’s high throughput experimental solution for solid state Lithium-ion battery research. Figure 1

Engineering an Injectable Muscle-Specific Microenvironment for Improved Cell Delivery Using a Nanofibrous Extracellular Matrix Hydrogel.

Injection of skeletal muscle progenitors has the potential to be a minimally invasive treatment for a number of diseases that negatively affect vasculature and skeletal muscle, including peripheral artery disease. However, success with this approach has been limited because of poor transplant cell survival. This is primarily attributed to cell death due to extensional flow through the needle, the harsh ischemic environment of the host tissue, a deleterious immune cell response, and a lack of biophysical cues supporting exogenous cell viability. We show that engineering a muscle-specific microenvironment, using a nanofibrous decellularized skeletal muscle extracellular matrix hydrogel and skeletal muscle fibroblasts, improves myoblast viability and maturation in vitro. In vivo, this translates to improved cell survival and engraftment and increased perfusion as a result of increased vascularization. Our results indicate that a combinatorial delivery system, which more fully recapitulates the tissue microenvironment, can improve cell delivery to skeletal muscle.

Tumor-targeted polymeric nanostructured lipid carriers with precise ratiometric control over dual-drug loading for combination therapy in non-small-cell lung cancer.

Gemcitabine (GEM) and paclitaxel (PTX) are effective combination anticancer agents against non-small-cell lung cancer (NSCLC). At the present time, a main challenge of combination treatment is the precision of control that will maximize the combined effects. Here, we report a novel method to load GEM (hydrophilic) and PTX (hydrophobic) into simplex tumor-targeted nanostructured lipid carriers (NLCs) for accurate control of the ratio of the two drugs. We covalently preconjugated the dual drugs through a hydrolyzable ester linker to form drug conjugates. N-acetyl-d-glucosamine (NAG) is a glucose receptor-targeting ligand. We added NAG to the formation of NAG-NLCs. In general, synthesis of poly(6-O-methacryloyl-d-galactopyranose)–GEM/PTX (PMAGP-GEM/PTX) conjugates was demonstrated, and NAG-NLCs were prepared using emulsification and solvent evaporation. NAG-NLCs displayed sphericity with an average diameter of 120.3±1.3 nm, a low polydispersity index of 0.233±0.04, and accurate ratiometric control over the two drugs. A cytotoxicity assay showed that the NAG-NLCs had better antitumor activity on NSCLC cells than normal cells. There was an optimal ratio of the two drugs, exhibiting the best cytotoxicity and combinatorial effects among all the formulations we tested. In comparison with both the free-drug combinations and separately nanopackaged drug conjugates, PMAGP-GEM/PTX NAG-NLCs (3:1) exhibited superior synergism. Flow cytometry and confocal laser scanning microscopy showed that NAG-NLCs exhibited higher uptake efficiency in A549 cells via glucose receptor-mediated endocytosis. This combinatorial delivery system settles problems with ratiometric coloading of hydrophilic and hydrophobic drugs for tumor-targeted combination therapy to achieve maximal anticancer efficacy in NSCLC.

One-Pot Combinatorial Biosynthesis of Glycosylated Anthracyclines by Cocultivation of Streptomyces Strains Producing Aglycones and Nucleotide Deoxysugars.

Anthracyclines, such as doxorubicin, are effective anticancer drugs composed of a tetracyclic polyketide aglycone and one or more deoxysugar moieties, which play a critical role in their biological activity. A facile one-pot combinatorial biosynthetic system was developed for the generation of a range of glycosylated derivatives of anthracyclines. Cocultivation of Streptomyces venezuelae mutants producing two anthracycline aglycones with eight different nucleotide deoxysugar-producing S. venezuelae mutants that coexpress a substrate-flexible glycosyltransferase led to the generation of 16 aklavinone or ε-rhodomycinone glycosides containing diverse deoxysugar moieties, seven of which are new. This demonstrates the potential of the one-pot combinatorial biosynthetic system based on cocultivation as a facile biological tool capable of combining diverse aglycones and deoxysugars to generate structurally diverse polyketides carrying engineered sugars for drug discovery and development.

Engineered biosynthesis of milbemycins in the avermectin high-producing strain Streptomyces avermitilis

BackgroundMilbemycins, produced from Streptomyces hygroscopicus subsp. aureolacrimosus and Streptomyces bingchenggensis, are 16-membered macrolides that share structural similarity with avermectin produced from Streptomyces avermitilis. Milbemycins possess strong acaricidal, insecticidal, and anthelmintic activities but low toxicity. Due to the high commercial value of the milbemycins and increasing resistance to the avermectins and their derivatives, it is imperative to develop an efficient combinatorial biosynthesis system exploiting an overproduction host strain to produce the milbemycins and novel analogs in large quantities.ResultsThe respective replacement of AveA1 and AveA3 (or module 7 in AveA3) of the avermectin polyketide synthase (PKS) in the avermectin high-producing strain S. avermitilis SA-01 with MilA1 and MilA3 (or module 7 in MilA3) of the milbemycin PKS resulted in the production of milbemycins A3, A4, and D in small amounts and their respective C5-O-methylated congener milbemycins B2, B3, and G as major products with total titers of approximately 292 mg/l. Subsequent inactivation of the C5-O-methyltransferase AveD led to a production of milbemycins A3/A4 (the main components of the commercial product milbemectin) in approximately 225 and 377 mg/l in the flask and 5 l fermenter culture, respectively, along with trace amounts of milbemycin D.ConclusionsWe demonstrated that milbemycin biosynthesis can be engineered in the avermectin-producing S. avermitilis by combinatorial biosynthesis with only a slight decrease in its production level. Application of a similar strategy utilizing higher producing industrial strains will provide a more efficient combinatorial biosynthesis system based on S. avermitilis for further enhanced production of the milbemycins and their novel analogs with improved insecticidal potential.

Synergistic chemotherapeutic effect of sorafenib-loaded pullulan-Dox conjugate nanoparticles against murine breast carcinoma.

pH-Sensitive pullulan-doxorubicin conjugates encapsulating sorafenib (P-Dox/S) nanoparticles were developed as a synergistic combinatorial delivery system against murine breast carcinoma. The nanoparticles can encapsulate Dox and sorafenib with ultra-high loading capacity (65.34 wt%) through chemical conjugation and physical loading, whereas can remain stable under physiological conditions and gradually release Dox and sorafenib with the decreasing pH. These conjugates can be effectively internalized and clearly suppress 4T1 cell growth in vitro. Furthermore, research data of in vivo animal models revealed that the synergistic combinatorial P-Dox/S nanoparticles heavily accumulated in solid tumor tissue sites to maximize therapeutic efficacy; they also significantly inhibited solid tumor growth, even remarkably reduced solid tumor volume in comparison to the initial volume, and obviously diminished adverse effects. The anti-tumor therapeutic effect obviously outperformed the delivery of combinational chemotherapy of free drugs or single drug-loaded P-Dox nanoparticles at the same concentration. These promising results indicate the high-efficiency synergistic chemotherapeutic effects of these nanoparticles. Combinational chemotherapy using P-Dox/S nanoparticles has important potential in the clinical treatment of malignancy for overcoming drug resistance and heterogeneity.