Unusual flexibility of mesophase pitch-derived carbon materials:an approach to the synthesis of graphene

Structural flexibility in a petroleum pitch-derived carbon material has been indirectly evaluated using X-ray diffraction (XRD), immersion calorimetry and inelastic neutron scattering (INS) measurements. Exposure of the carbon material to an organic solvent (e.g., n-nonane) gives rise to a large internal rearrangement, associated with a drastic re-ordering of the graphitic microdomains. These structural changes are also associated with a high flexibility of the internal porous network, as observed by inelastic neutron scattering measurements. The internal rearrangement and the structural flexibility could be responsible for the excellent performance of this kind of activated carbons in a wide variety of adsorption processes. Last but not least, the structural characteristics of these carbon materials composed of graphitic microdomains has been used to synthesize graphene “egg-like” flakes following a simple procedure based on exfoliation with organic solvents

Drug-eluting wound dressings having sustained release of antimicrobial compounds

Wound healing is a complex and costly public health problem that should be timely addressed to achieve a rapid and adequate tissue repair avoiding or even eliminating potential pathogenic infection. Chronic infected non-healing wounds represent a serious concern for health care systems. Efficient wound dressings with tailored therapy having the best response and highest safety margin for the management of chronic non-healing wounds are still needed. The use of novel wound dressing materials has emerged as a promising tool to fulfil these requirements. In this work, asymmetric electrospun polycaprolactone (PCL)-based nanofibers (NFs) were decorated with electrosprayed poly(lactic-co-glycolic acid) microparticles (PLGA MPs) containing the natural antibacterial compound thymol (THY) in order to obtain drug eluting antimicrobial dressings having sustained release. The synthesized dressings successfully inhibited the in vitro growth of Staphylococcus aureus ATCC 25923, showing also at the same doses cytocompatibility on human dermal fibroblasts and keratinocyte cultures after treatment for 24 h, which was not observed when using free thymol. An in vivo murine excisional wound splinting model, followed by the experimental infection of the wounds with S. aureus and their treatment with the synthesized dressings, pointed to the reduction of the bacterial load in wounds after 7 days, though the total elimination of the infection was not reached. The findings indicated the relevance of the direct contact between the dressings and the bacteria, highlighting the need to tune their design considering the wound surface and the nature of the antimicrobial cargo contained

Efficiency of Antimicrobial Electrospun Thymol-Loaded Polycaprolactone Mats in Vivo

Due to the prevalence of antimicrobial resistant pathogens, natural products with long-term antimicrobial activities are considered as potential alternatives. In this work, polycaprolactone (PCL) electrospun fibers with mean diameters around 299 nm and loaded with 14.92 ± 1.31% w/w thymol (THY) were synthesized. The mats had appropriate elongation at break (74.4 ± 9.5%) and tensile strength (3.0 ± 0.5 MPa) to be potentially used as wound dressing materials. In vivo studies were performed using eight to ten week-old male SKH1 hairless mice. The infection progression was evaluated through a semiquantitative method and quantitative polymerase chain reaction. The analyses of post-mortem samples indicated that THY-loaded PCL fibers acted as inhibitors of Staphylococcus aureus ATCC 25923 strain growth being as efficient as chlorhexidine (CLXD). Histopathological and immunohistochemical studies showed that the PCL-THY-treated wounds were almost free of an inflammatory reaction. Therefore, wound dressings containing natural compounds can prevent infection and promote wound healing and prompt regeneration. Copyrigh

Crocin improves the quality of cryopreserved goat semen in different breeds

The effect of crocin in the semen extender before cryopreservation was evaluated on sperm parameters of 20 bucks of five different breeds: Garganica (GA), Jonica (JO), Maltese (MA), Mediterranean Red (MR) and Saanen (SA). Semen samples were centrifuged, to remove seminal plasma, divided in two aliquots and diluted with Tris-egg-yolk-based extender, containing 0 (control group) and 1 mM crocin. Crocin concentration was established after a preliminary dose trial. On fresh and frozen-thawed sperm, motility, viability, morphology, membrane integrity, DNA fragmentation and ROS levels were evaluated. The freezing process led to a decrease (p < 0.05) in all the sperm parameters recorded, confirming the deleterious effect of cryopreservation on goat semen. The most interesting result regarding the inclusion of crocin in the extender before cryopreservation was as follows: Crocin significantly improved (p < 0.05) sperm motility in all breeds, except for Mediterranean Red, compared to the control group. Furthermore, 1 mM crocin reduced percentage of spermatozoa with DNA fragmentation with a marked decrement (p < 0.05) in Garganica and Saanen, as compared to the control group. Finally, intracellular ROS decreased (p < 0.01) in the crocin-treated sperm of all breeds, as compared to the control. In conclusion, supplementation of 1 mM crocin in the extender decreased oxidative stress, improving sperm motility and the DNA integrity of frozen-thawed sperm in different breeds

Search for the rare decay Λc+ →pμ+μ-

The flavor-changing neutral-current (FCNC) decay Λþ c → pμþμ− (inclusion of the charge-conjugate processes is implied throughout) is expected to be heavily suppressed in the Standard Model (SM) by the Glashow-IliopoulosMaiani mechanism [1]. The branching fractions for shortdistance c → ulþl− contributions to the transition are expected to be of Oð10−9Þ in the SM but can be enhanced by effects beyond the SM. However, long-distance contributions proceeding via a tree-level amplitude, with an intermediate meson resonance decaying into a dimuon pair [2,3], can increase the branching fraction up to Oð10−6Þ [4]. The short-distance and hadronic contributions can be separated by splitting the data set into relevant regions of dimuon mass. The Λþ c → pμþμ− decay has been previously searched for by the BABAR Collaboration [5], yielding 11.1 5.0 2.5 events and an upper limit on the branching fraction of 4.4 × 10−5 at 90% C.L. Similar FCNC transitions for the b-quark system (b → slþl−) exhibit a pattern of consistent deviations from the current SM predictions both in branching fractions [6] and angular observables [7], with the combined significance reaching 4 to 5 standard deviations [8,9]. Processes involving c → ulþl− transitions are far less explored at both the experimental and theoretical levels, which makes such measurements desirable. Similar analyses of the D system have reported evidence for the longdistance contribution [10]; however, the short-distance contributions have not been established [11]

Design of a Functionalized Metal-Organic Framework System for Enhanced Targeted Delivery to Mitochondria.

Mitochondria play a key role in oncogenesis and constitute one of the most important targets for cancer treatments. Although the most effective way to deliver drugs to mitochondria is by covalently linking them to a lipophilic cation, the in vivo delivery of free drugs still constitutes a critical bottleneck. Herein, we report the design of a mitochondria-targeted metal-organic framework (MOF) that greatly increases the efficacy of a model cancer drug, reducing the required dose to less than 1% compared to the free drug and ca. 10% compared to the nontargeted MOF. The performance of the system is evaluated using a holistic approach ranging from microscopy to transcriptomics. Super-resolution microscopy of MCF-7 cells treated with the targeted MOF system reveals important mitochondrial morphology changes that are clearly associated with cell death as soon as 30 min after incubation. Whole transcriptome analysis of cells indicates widespread changes in gene expression when treated with the MOF system, specifically in biological processes that have a profound effect on cell physiology and that are related to cell death. We show how targeting MOFs toward mitochondria represents a valuable strategy for the development of new drug delivery systems

Control of the pore size distribution and its spatial homogeneity in particulate activated carbon

There are circumstances where it is desirable to achieve a particular, optimal, pore size distribution (PSD) in a carbon, including in the molecular sieving, gas storage, CO2-capture and electrochemical energy storage. Activation protocols that cycle a carbon a number of times between a low-temperature oxygen chemisorption process and a higher temperature pyrolysis process have been proposed as a means of yielding such desired PSDs. However, it is shown here that for PFA-based char particles of ∼100 μm in size, only the super-micropores are substantially developed under such an activation protocol, with the ultra-micropores being substantially un-touched. It is also shown that a typical CO2-activation process yields similar control over PSD development. As this process is nearly 15 times faster than the cyclic-O2 protocol and yields larger pore volumes and areas for a given level of conversion, it is to be preferred unless spatial homogeneous porosity within the particles is also desired. If such homogeneity is desired, it is shown here that CO2 activation should continue to be used but at a rate of around one-tenth the typical; this slow rate also has the advantage of producing pore volumes and areas substantially greater than those obtained using the other activation protocols.CH acknowledges a joint scholarship provided by China Scholarship Council (CSC) and the University of Adelaide. SS acknowledges the award of International Postgraduate Research Scholarship (IPRS) from the University of Adelaide. SHM acknowledges the award of a President’s Scholarship from the University of South Australia. The support of the Australian Research Council Discovery Program (DP110101293) is also gratefully acknowledged

Supramolecular Nucleic Acid-Based Organosilica Nanoparticles Responsive to Physical and Biological Inputs

Organosilica nanoparticles that contain responsive organic building blocks as constitutive components of the silica network offer promising opportunities for the development of innovative drug formulations, biomolecule delivery, and diagnostic tools. However, the synthetic challenges required to introduce dynamic and multifunctional building blocks have hindered the realization of biomimicking nanoparticles. In this study, capitalizing on our previous research on responsive nucleic acid-based organosilica nanoparticles, we combine the supramolecular programmability of nucleic acid (NA) interactions with sol-gel chemistry. This approach allows us to create dynamic supramolecular bridging units of nucleic acids in a silica-based scaffold. Two peptide nucleic acid-based monoalkoxysilane derivatives, which self-assemble into a supramolecular bis-alkoxysilane through direct base pairing, were chosen as the noncovalent units inserted into the silica network. In addition, a bridging functional NA aptamer leads to the specific recognition of ATP molecules. In a one-step bottom-up approach, the resulting supramolecular building blocks can be used to prepare responsive organosilica nanoparticles. The supramolecular Watson-Crick-Franklin interactions of the organosilica nanoparticles result in a programmable response to external physical (i.e., temperature) and biological (i.e., DNA and ATP) inputs and thus pave the way for the rational design of multifunctional silica materials with application from drug delivery to theranostics