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One of the fundamental questions in developmental biology is what determines the final size and shape of an organ. Recent research strongly emphasizes that besides cell-cell communication, biophysical principals govern organ development. The architecture and mechanics of a tissue guide cellular processes such as movement, growth or differentiation. Furthermore, mechanical cues do not only regulate processes at a cellular level but also provide constant feedback about size and shape on a tissue scale. Here we review several models and experimental systems which are contributing to our understanding of the roles mechanical forces play during organ development. One of the best understood processes is how the remodeling of bones is driven by mechanical load. Culture systems of single cells and of cellular monolayers provide further insights into the growth promoting capacity of mechanical cues. We focus on the Drosophila wing imaginal disc, a well-established model system for growth regulation. We discuss theoretical models that invoke mechanical feedback loops for growth regulation and experimental studies providing empirical support. Future progress in this exciting field will require the development of new tools to precisely measure and modify forces in living tissue systems. [ABSTRACT FROM AUTHOR]

A solution-chemistry approach was developed to prepare carbon-coated Li 3 V 2 (PO 4 ) 3 nanoparticles embedded in a micrometer-sized carbon matrix. The material was obtained by a facile one-pot synthesis involving a protic ionic liquid as a soft template and carbon source. To the best of our knowledge, the rate performance of electrodes based on this material is among the highest reported so far for Li 3 V 2 (PO 4 ) 3 due to the favorable nanoarchitecture combined with high electronic conductivity of the material. The capacity of the electrode only smoothly declines with increasing current density and reaches a value of about 100 mAh g −1 at 100C when cycled between 3.0–4.3 V vs. Li/Li + . Furthermore, excellent capacity retention of 70% after 10,000 cycles at 50C is demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: We investigate how residual catalyst from carbon nanotube (CNT) templates can be used to engineer novel functional nanomaterials. CNTs, produced via continuous flow chemical vapour deposition, typically contain catalyst residues in the form of encapsulated metal clusters or of iron oxide nanoparticles attached to the outside of the CNTs. These CNTs are used as sacrificial templates for TiO2 coatings using benzyl alcohol as a linking agent. Upon oxidation of the CNTs, the encapsulated iron particles dissolve into the TiO2 lattice and form iron-doped TiO2 nanotubes without the formation of secondary phases, while the iron oxide particles merely attach to the outer surface. The materials show extended light absorption into the visible range, a requirement for visible-light photocatalyst. [Copyright &y& Elsevier]

[Display omitted] Metal-organic frameworks (MOFs) hold potential for promoting the redox reaction of sulfur species (RRS) and suppressing the shuttle effect in lithium–sulfur batteries (LSBs). However, except for a limited number of frameworks, most MOFs are found to be inert in accelerating RRS, which is largely related to the fact that their design principles and mechanism of catalysis have not been fully understood. Systematic density functional theory (DFT) calculations and experimental results reveal that the lack of exposed polar catalytic sites restricts MOF's potential in promoting RRS. Herein, based on a series of multivariable MOFs containing ligands with different thermal stability, selective ligand removal and ligand exchange (LE) strategies were applied successively to expose the catalytic metal clusters and introduce extra adsorption sites, rendering inert MOFs into catalytic ones. Such post-modified multivariable MOFs were shown to yield LSBs with remarkably improved specific capacity and cycling stability realizing 7.9 mAh cm−2 of capacity after 100 cycles at high sulfur loading of 8.1 mg·cm−2 under a lean electrolyte condition. The universal strategy proposed in this work will guide the design of catalytic MOFs for RRS and promote the development of advanced catalysts for high-performance LSBs. [ABSTRACT FROM AUTHOR]

Recently, carbon spherogels have been introduced as a novel monolithic aerogel composed of hollow spheres. This material is conveniently obtained via polystyrene (PS) sphere templating. In the present study, we apply a water-soluble titania precursor (titanium(IV) bis(ammonium lactate) to the aqueous sol-gel synthesis based on resorcinol-formaldehyde (RF) to effectively encapsulate titania. In this way, a very high mass loading of up to 59 mass% of titania can be confined strictly to the inside of the hollow carbon spheres. In the final synthesis step, carbonization at 800 °C has three simultaneous effects: Transformation of the RF coating on PS into microporous carbon, PS template removal by decomposition, and formation of titania due to precursor dissociation. A deliberate tuning of the microporous carbon shell, accessibility of the titania, titania amount, and titania's polymorph is further demonstrated by thermal treatment under a carbon dioxide atmosphere. In contrast to non-tuned or TiC-containing carbon spherogels, CO 2 activation of the composites results in a three orders of magnitude rise of their photocatalytic activity towards hydrogen evolution reaction, which we evaluate using flow and batch reactors. We further show that this effect is related to the partial etching of the carbon shell, which renders the TiO 2 surface accessible to the reactants in the solution and allows for an efficient hole scavenging. Given the simplicity of the hybrid carbon spherogel (HCS) composite fabrication, the high degree of control of their morphological characteristics, and the striking effects of CO 2 -activation on performance, we believe that our results will contribute to the development of similar carbon-inorganic composites. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Acetate ion functionalized polar ionic liquid (IL), 1-allyl-3-methylimidazolium acetate (AMIMOAc), has firstly been used not only as an additive in MAPbI 3 perovskite film but also as an interfacial modification layer between SnO 2 and MAPbI 3 in carbon counter electrode-based perovskite solar cells. • The appropriate content of IL can reduce the number of trap states in MAPbI 3 perovskite film to inhibit non-radiative recombination and increase carrier lifetime, further improve the PCE to 15.16%. • The stability of the devices has been improved remarkably. The device with AMIMOAc IL has retained 93% of its initial PCE after storing for 500 h. The potential of perovskite solar cells as a representative alternative to silicon-based solar cells has become significant owing to their unparalleled advancement in efficiency. However, the intrinsic instability of perovskite still hinders their large-scale commercial application, particularly of the decomposition of perovskite during device operation. To address this issue, an acetate-ion-functionalized polar ionic liquid, 1-allyl-3-methylimidazolium acetate (AMIMOAc), is used as an additive in MAPbI 3 film. FTIR spectroscopy measurements show that AMIMOAc can anchor the organic cations via hydrogen bonding and enhance the Pb–O interaction in modified MAPbI 3 , leading to a continuous and dense morphology to increase the stability of MAPbI 3. After optimizing the concentration of AMIMOAc, an additional interfacial modification layer accelerates the electron extraction and transport. By the synergy of both additive engineering and interface modification, the device not only achieves a high efficiency of 15.16%, but also maintains 93% of the initial PCE after 500 h, showing significantly improved stability. These results pave the way to a new strategy to improve efficiency and long-term stability of carbon counter electrode-based PSCs. [ABSTRACT FROM AUTHOR]

Abstract: We synthesized highly porous composite films of vertically aligned carbon nanotubes (CNTs) and polypyrrole (PPy) by employing a simple in situ electropolymerisation process from aqueous pyrrole solutions. By contacting the entire CNT array, each CNT acts as a highly active anode that facilitates uniform deposition and immediate polymerization of pyrrole directly on the CNT surface. As a result, each individual CNT was coated with a thin layer of PPy with a tunable thickness between 4 and 38nm. At the same time the vertical array structure of the CNTs was preserved. A major advantage of this route is that the resulting composite film is highly porous and can be post-filled with other polymers, metals or ceramics to create new multifunctional composites and hybrid structures. [Copyright &y& Elsevier]

• Fe 2 P catalyst induces electrochemical reduction of N 2 to NH 3 in alkaline medium. • Combination of Fe0 and P sites form active centers at the electrocatalytic interface. • Fe 2 P is characterized by reasonable selectivity with respect to hydrogen evolution. • Fe 2 P also exhibits catalytic properties toward electroreduction of O 2 , NO 3 − and NO 2 −. • The NH 3 product can be detected by voltammetric oxidation at Pt nanoparticles. A catalytic system based on iron phosphide (Fe 2 P) has exhibited electrocatalytic activity toward N 2 -reduction reaction in alkaline medium (0.5 mol dm−3 NaOH). Based on voltammetric stripping-type electroanalytical measurements, Raman spectroscopic and spectrophotometric data, it can be stated that the Fe 2 P catalyst facilitates conversion of N 2 to NH 3 , and the process is fairly selective with respect to the competing hydrogen evolution. A series of diagnostic electrocatalytic experiments (utilizing platinum nanoparticles and HKUST-1) have been proposed and performed to control purity of nitrogen gas and to probe presence of potential contaminants such as ammonia, nitrogen oxo-species and oxygen. On the whole, the results are consistent with the view that the interfacial reduced-iron (Fe0) centers, while existing within the network of P sites, induce activation and reduction of nitrogen, parallel to the water splitting (reduction) to hydrogen. It is apparent from Tafel plots and impedance measurements that mechanism and dynamics of nitrogen reduction depends on the applied electroreduction potential. The catalytic system exhibits certain tolerance with respect to the competitive hydrogen evolution and gives (during electrolysis at -0.4 V vs. RHE) the Faradaic efficiency, namely, the selectivity (molar) efficiency, toward production of NH 3 on the level of 60%. Under such conditions, the NH 3 -yield rate has been found to be equal to 7.5 µmol cm−2 h−1 (21 µmol m−2 s−1). By referring to classic concepts of electrochemical kinetic analysis, the rate constant in heterogeneous units has been found to be on the moderate level of 1-2*10−4 cm s−1 (at -0.4 V). The above mentioned iron-phosphorous active sites, which are generated on surfaces of Fe 2 P particles, have also been demonstrated to exhibit strong catalytic properties during reductions of other electrochemically inert reactants, such as oxygen, nitrites and nitrates. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • CS nanoparticles loaded with oxacillin and DNase (CSNP-DNase-Oxa) were fabricated. • CSNP-DNase-Oxa exhibited the best antibiofilm activity in all in-vitro tests. • CSNP-DNase-Oxa reduced the biofilm matrix, thickness and the amount of viable cells. • CSNP-DNase-Oxa showed the highest eradication of clinical isolates biofilms. Abstract Bacterial biofilms play a key role during infections, which are associated with an increased morbidity and mortality. The classical antibiotic therapy cannot eradicate biofilm-related infections because biofilm bacteria display high drug resistance due to biofilm matrix. Thus, novel drug delivery to overcome biofilm resistance and eliminate biofilm-protected bacteria is needed to be developed. In this study, positively charged chitosan nanoparticles (CSNP) loaded with oxacillin (Oxa) and Deoxyribonuclease I (CSNP-DNase-Oxa) were fabricated. The antibiofilm activity was evaluated against Staphylococcus aureus biofilms. Biofilm architecture on silicone surfaces was investigated by scanning electron microscopy (SEM). Confocal laser scanning microscopy (CLSM) was used to examine live/dead organisms within biofilm. CSNP-DNase-Oxa exhibited higher antibiofilm activity than Oxa-loaded nanoparticles without DNase (CSNP-Oxa) and free Oxa (Oxa and Oxa + DNase) at each concentration in all in-vitro tests. CSNP-DNase-Oxa inhibited biofilm formation in-vitro and eradicated mature biofilm effectively. CSNP-DNase-Oxa could disrupt the biofilm formation through degradation of eDNA, reduced biofilm thickness and the amount of viable cells on silicone. Repeated treatment with CSNP-DNase-Oxa for two days resulted in 98.4% biofilm reduction. Moreover, CSNP-DNase-Oxa was not only able to affect the biofilm of a standard S. aureus strain, but also showed the highest eradication of biofilms of clinical isolates compared with control groups. These results suggest the potential applicability of NPs for the treatment of biofilm-related infections and provide a platform for designing novel drug delivery with more functions. [ABSTRACT FROM AUTHOR]

This work demonstrates the fabrication of a high-efficiency, hole-conductor-free, solid-state perovskite solar cell with TiO 2 -nanorod arrays (NRAs) as photoanodes and commercial carbon ink as counter-electrodes. TiO 2 -NRA films of various thicknesses were deposited on FTO electrodes through hydrothermal method for different reaction durations. The effect of the thickness of TiO 2 -NRA films on device performance was investigated in detail. The TiO 2 NRAs/CH 3 NH 3 PbI 3 /C devices based on 688 nm-thick TiO 2 -NRA films exhibited the optimal performance and power conversion efficiency (PCE) of as high as 8.56%. This value is comparable with the PCE of the recently reported TiO 2 NRA/Perovskite/HTM/Au solar cell. [ABSTRACT FROM AUTHOR]

A series of five decavanadates (V 10) using a simple, one-pot synthesis, adhering to the model template: transition metal ion – decavanadate – ligands :(H nicotinamide) 2 {[Co(H 2 O) 3 (nicotinamide) 2 ] 2 [ μ -V 10 O 28 ]}.6H 2 O (1) , {[Co(H 2 O) 4 (isonicotinamide) 2 ] 3 }V 10 O 28 ·4H 2 O (2) , {[Co(H 2 O) 4 ] 2 [Co(H 2 O) 2 (μ - pyrazinamide) 2 ][ μ -V 10 O 28 ]}·4H 2 O (3) {[Co(H 2 O) 4 (μ - pyrazinamide)] 3.V 10 O 28 }·4H 2 O (4) , and (NH 4) 2 {[Ni(H 2 O) 4 (2 -hydroxyethylpyridine)] 2 }V 10 O 28 ·2H 2 O (5) was synthesized. X-ray analysis reveals that 1 and 3 are decavanadato complexes, while 2 , 4 and 5 are decavanadate complex salts. Moreover, 3 is the first example of a polymeric decavanadato complex, employing direct coordination with the metal center and the organic ligand, in toto. From the solution studies using 51V NMR spectroscopy, it was decoded that 1 and 3 stay stable in the model buffer solution and aqueous media. Binding to model proteins, cytotoxicity and water oxidation catalysis (WOC) was studied primarily for 1 and 3 and concluded that neither 1 nor 3 have an interaction with the model proteins thaumatin, lysozyme and proteinase K, because of the presence of the organic ligands in the Co(II) center, any further interplay with the proteins was blocked. Cytotoxicity studies reveal that 1 is 40% less toxic (0.05 m M) and 26% less toxic (0.1 m M) than the uncoordinated V 10 with human cell lines A549 and HeLa respectively. In WOC, 1 performed superior activity, by evolving 143.37 nmol of O 2 which is 700% (9-fold) increase than the uncoordinated V 10. SYNOPSIS Coordination of decavanadate anion to cobalt(II) complex cations with organic ligands enhanced its stability in solutions allowing in-depth study of synthesis conditions, water oxidation catalysis reaction, cytotoxicity and protein binding. [Display omitted] • Five new decavanadates with transition metal complex cations were prepared. • The coordination of decavanadate to cobalt(II) stabilizes it in solution. • Free decavanadate is more toxic than a coordinated for HeLa and A549 cell lines. • Coordination by cobalt(II) center with isonicotinamide ligand increases WOC activity. [ABSTRACT FROM AUTHOR]

Methylammonium bismuth iodide ((CH 3 NH 3) 3 Bi 2 I 9 , MBI) is a promising alternative to perovskite solar cells (PSCs) due to its air stability and low-toxicity. Herein, a two-stage electric-field-assisted reactive deposition method has been introduced to prepare MBI films for the first time. PSCs based on MBI films were fabricated and characterized. The influences of electric parameters (applied voltage mode, pulse and time, etc.) on the morphology and crystal structure of MBI film correlated with the photovoltaic performance of PSCs have also been investigated systematically in detail. Through adjusting the voltage mode, crystal growth can be completely controlled, leading to a compact MBI film with large grain size. Moreover, the MBI film prepared by electrochemical deposition required no annealing. This work determined that the optimal performance of PSCs is based on the MBI film deposited by square-wave (AC) voltage mode (−7.3 V/+1 V, 5 Hz, 5 min). All devices exhibited long-term stability in ambient air (humidity of >50%) for more than 300 h. This study will inspire further research on the application of electrochemical deposition technique for other lead-free PSCs. Image 1 • A two-stage electric-field-assisted reactive deposition method has been introduced to prepare (CH 3 NH 3) 3 Bi 2 I 9 films for the first time. • The influences of electric parameters on MBI film morphology and crystal structure correlating with the photovoltaic performance of PSCs have been investigated systematically. • The proposed electrochemical deposition method is facile, controllable, and repeatable, and significant to the commercial production of perovskite. • The proposed electrochemical deposition involves an annealing-free fabrication, thus simplifying the process and promoting production efficiency. [ABSTRACT FROM AUTHOR]