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Future space travel needs ultra-lightweight and robust structural materials that can withstand extreme conditions with multiple entry points to orbit to ensure mission reliability. This is unattainable with current inorganic materials. Ultra-highly stable carbon fiber reinforced polymers (CFRPs) have shown susceptibility to environmental instabilities and electrostatic discharge, thereby limiting the full lightweight potential of CFRP. A more robust and improved CFRP is needed in order to improve space travel and structural engineering further. Here, we address these challenges and present a superlattice nano-barrier-enhanced CFRP with a density of ~3.18 g/cm3 that blends within the mechanical properties of the CFRP, thus becoming part of the composite itself. We demonstrate composites with enhanced radiation resistance coupled with electrical conductivity (3.2 × 10-8 ohm⋅m), while ensuring ultra-dimensionally stable physical properties even after temperature cycles from 77 to 573 K.

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The endeavors to develop manufacturing methods that can enhance polymer and composite structures in spacecraft have led to much research and innovation over many decades. However, the thermal stability, intrinsic material stress, and anisotropic substrate properties pose significant challenges and inhibit the use of previously proposed solutions under extreme space environment. Here, we overcome these issues by developing a custom-designed, plasma-enhanced cross-linked poly(p-xylylene):diamond-like carbon superlattice material that enables enhanced mechanical coupling with the soft polymeric and composite materials, which in turn can be applied to large 3D engineering structures. The superlattice structure developed forms an integral part with the substrate and results in a space qualifiable carbon-fiber-reinforced polymer featuring 10-20 times greater resistance to cracking without affecting the stiffness of dimensionally stable structures. This innovation paves the way for the next generation of advanced ultra-stable composites for upcoming optical and radar instrument space programs and advanced engineering applications.

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With the realization of larger and more complex space installations, an increase in the surface area exposed to atomic oxygen (AO) and ultraviolet (UV) effects is expected, making structural integrity of space structures essential for future development. In a low Earth orbit (LEO), the effects of AO and UV degradation can have devastating consequences for polymer and composite structures in satellites and space installations. Composite materials such as carbon fiber-reinforced polymer (CFRP) or polymer materials such as polyetherimide and polystyrene are widely used in satellite construction for various applications including structural components, thermal insulation, and importantly radio frequency (RF) assemblies. In this paper, we present a multilayered material protection solution, a multilayered protection barrier, that mitigates the effects of AO and UV without disrupting the functional performance of tested assemblies. This multilayered protection barrier deposited via a custom-built plasma-enhanced chemical vapor deposition (PECVD) system is designed so as to deposit all necessary layers without breaking vacuum to maximize the adhesion to the surface of the substrate and to ensure no pinhole erosion is present. In the multilayer solution, a moisture and outgassing barrier (MOB) is coupled with an AO and UV capping layer to provide complete protection.

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Graphene-based carbon sponges can be used in different applications in a large number of fields including microelectronics, energy harvesting and storage, antimicrobial activity and environmental remediation. The functionality and scope of their applications can be broadened considerably by the introduction of metallic nanoparticles into the carbon matrix during preparation or post-synthesis. Here, we report on the use of X-ray micro-computed tomography (CT) as a method of imaging graphene sponges after the uptake of metal (silver and iron) nanoparticles. The technique can be used to visualize the inner structure of the graphene sponge in 3D in a non-destructive fashion by providing information on the nanoparticles deposited on the sponge surfaces, both internal and external. Other deposited materials can be imaged in a similar manner providing they return a high enough contrast to the carbon microstructure, which is facilitated by the low atomic mass of carbon.

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Graphene is a desirable material for next generation technology. However, producing high yields of single-layer flakes with industrially applicable methods is currently limited. We introduce a combined process for the reduction of graphene oxide (GO) via vitamin C (ascorbic acid) and thermal annealing at temperatures of <150 °C for times of <10 minutes, resulting in electrically conducting thin films with sheet resistances reducing by 8 orders of magnitude to as low as ∼1.3 kΩ â–¡-1, suitable for microelectronics, display technology and optoelectronic applications. The in-depth physicochemical characterisation of the products at different stages of GO preparation and reduction allows for further understanding of the process and demonstrates the suitability for industrial production methodologies due to an environmentally-friendly reducing agent, solution processability and no requirement for high temperatures. The presence of the vitamin C lowers the temperature required to thermally reduce the GO into an electrically conducting thin film, making the technique suitable for thermally sensitive substrates, such as low melting point polymers. Simultaneous spray coating and reduction of GO allows for large area deposition of conductive coatings without sacrificing solution processability, often lost through particle agglomeration, making it compatible with industrial processes, and applicable to, for example, the production of sensors, energy devices and flexible conductive electrodes for touchscreens.

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We report a ZnO interfacial layer based on an environmentally friendly aqueous precursor for organic photovoltaics. Inverted PCDTBT devices based on this precursor show power conversion efficiencies of 6.8-7%. Unencapsulated devices stored in air display prolonged lifetimes extending over 200 hours with less than 20% drop in efficiency compared to devices based on the standard architecture.

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Conspicuous absence: (29)SiNMR studies show that highly condensed, four-coordinate Si-containing anions are common in concentrated alkali-metal silicate solutions, but reveal no evidence for the existence of specialized zeolite building units. The results add to the mounting evidence that silicate polymerization simply proceeds through stepwise condensation of monosilicate tetrahedra.

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The authors of a recent report in this journal (Houssin, et al., Phys. Chem. Chem. Phys., 2003, 5, 3518, ) claim that a tetrapropylammonium (TPA) silicate mixture with molar composition 4.41 TPAOH : 10 SiO(2) : 117 H(2)O contains high concentrations of two silicate oligomers, the prismatic double five-ring and a novel pentacyclic dodecamer. The latter species is derivative of the framework structure of silicalite-1, a MFI-type zeolite that spontaneously crystallizes from this system, and, indeed, the authors declare it to be a "nanoprecursor" in the TPA-mediated growth of silicalite-1. Using two-dimensional (29)Si COSY NMR spectroscopy to examine an equivalent mixture enriched in the (29)Si isotope, we show that the published peak assignments are erroneous. The signal assigned to the double five-ring corresponds, in reality, to the well-characterized pentacyclic octamer, while the three signals assigned to the pentacyclic dodecamer arise from three completely separate species. We find no evidence, therefore, to support the suggestion that silicalite-1 is formed by sequential condensation of precursor species any more complex than the simple orthosilicate anion.

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Addition of cis-1,2-dihydroxycyclopentane to aqueous alkaline silicate solutions results in the spontaneous formation of three organosilicate species, each with a 2:1 ligand to Si ratio and a pentacoordinated silicon centre. By using a mixture of both cis-1,2-dihydroxycyclopentane and 1,4-anhydroerythritol we show unambiguously that all three species are diastereomers of the monomeric bis(diolato)-hydroxo complex, [(L=)(2)SiOH](-)(where L represents the cis-diol ligand), thus clarifying the general assignment of (29)Si NMR spectra reported for silicate solutions containing furanoidic sugars with vicinal cis-diol functionality, such as ribose.

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A range of radiolabeled anthocyanins, proanthocyanidins, and other flavonoids were accumulated by cell suspension cultures of two plant species, ohelo (Vaccinium pahalae) and grape (a Vitis hybrid, Bailey Alicant A), after providing uniformly labeled [(14)C]sucrose to the medium. Approximately 15% of administered label was recovered in a series of flavonoid-rich fractions varying in composition. Anthocyanins, and monomers to oligomers of proanthocyanidins, were labeled effectively and characterized from both species. Most of the proanthocyanidin oligomers were based on the flavan-3-ols (+)-catechin and (-)-epicatechin. Cyanidin and peonidin glycosides were the dominant forms of anthocyanins in both species. Whereas the predominant form of flavonoids identified from ohelo cell cultures was proanthocyanidins, grape cell cultures produced mostly anthocyanins. The labeled phytochemicals were produced for use in subsequent in vivo animal feeding studies to gauge their bioavailability and accumulation in target organs.

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The addition of tetraalkylammonium cations to aqueous silicate solutions enhances the abundance of symmetric, cagelike, polysilicate anions including the cubic octamer, Si(8)O(20)(8)(-). The equilibrium ratio of tetramethylammonium (TMA) cations to the octameric silicate anion is 8:1 for solutions with a concentration ratio [OH(-)]:[Si] >/= 1:1. Evidence indicates that organocations directly associate with cagelike polyanions to form a protective shell of hydrophobic hydration that impedes hydrolysis of the central anion.

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The kinetics of formation of the silicate cubic octamer, Q(3)(8), in aqueous tetramethylammonium (TMA) silicate solutions was investigated by (29)Si NMR. The rate equation for solutions at pH 13.2-13.6 is d[Q(3)(8)]/dt = k(f) [H(+)](1.6)(+/-)(0.1)[TMA(+)](0.36)(+/-)(0.08)[Si](0.8)(+/-)(0.3) where k(f) = (2.2 +/- 0.8) x 10(16) mol(-)(1.8) kg(1.8) s(-)(1) at 296 K. The findings prove unequivocally that alkylammonium cations participate directly in the formation and subsequent stabilization of cagelike polysilicate anions. This implies a radically different mechanistic role than "templating" for alkylammonium cations in the synthesis of molecular sieves.

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An interactive minicomputer-based system has been developed that enables the clinical research investigator to personally explore and analyze his research data and, as a consequence of these explorations, to acquire more information. This system, which does not require extensive training or computer programming, enables the investigator to describe his data interactively in his own terms, enter data values while having them checked for validity, store time-oriented patient data in a carefully controlled on-line data base, retrieve data by patient, variable, and time, create subsets of patients with common characteristics, perform statistical analyses, and produce tables and graphs. It also permits data to be transferred to and from other computers. The system is well accepted and is being used by a variety of medical specialists at the three clinical research centers where it is operational. Reported benefits include less elapsed and nonproductive time, more thorough analysis of more data, greater and earlier insight into the meaning of research data, and increased publishable results.

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The acetylating radioenzymatic assay was used for determination of levels of amikacin in serum and urine. Because of an inhibitor present in various amounts in urine, assay of amikacin in urine by this method requires added internal standards and thus is less precise than the assay in serum. Determination of the rate of plasma clearance, half-life, and volume of distribution of amikacin in 10 patients with normal renal function, four patients undergoing dialysis, and five patients with end-stage renal diseases have shown a relation of half-life (t1/2 in hr) to rate of clearance of serum creatinine (Cer) of t1/2 = 3 X Cer, the same relation as found for kanamycin and gentamicin. The apparent steady-state volume of distribution of amikacin in patients with diminished renal function is slightly, but not significantly, larger than that in normal patients; the values were 0.28 +/- 0.10 and 0.21 +/- 0.10, respectively. In normal patients, 87% of the drug is excreted by the kidney.

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The authors describe three postmenopausal women with agitated psychotic depression, increased water ingestion, and electrolyte values consistent with the syndrome of inappropriate antidiuretic hormone (ADH) secretion. They hypothesize that this clinical triad represents a syndrome reflecting underlying dysfunction of the hypothalamus and limbic system of the brain. The diagnosis of inappropriate ADH in one of the patients was directly confirmed by a recently developed serum radioimmunoassay.

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