The sonochemical coating of cotton withstands 65 washing cycles at hospital washing standards and retains its antibacterial properties

Hospital-acquired nosocomial infections are a major health, and consequently financial issue, in the world healthcare system. The problem of bacterial infections in general, and in hospitals in particular, has led to extensive scientific and industrial efforts to fabricate antibacterial textiles. A sonochemical coating machine was developed and built and its ability to coat antibacterial nanoparticles (NPs) onto 40–50 meter length of materials on a roll to roll basis at a speed of 22 cm/min. Cotton coated sonochemically with copper oxide nanoparticles (CuO NPs) was found to maintain its antibacterial properties even after 65 cycles of washings according to hospital protocols of hygienic washing (75 °C). This demonstrates the good quality and high stability of this sonochemically produced NPs coating on textiles. Durable antibacterial textiles such as these may be suitable for wide spread use in future hospital environments where hygiene control is of paramount importance.     

A radioanalytical phantom for assessing the efficacy of electrokinetic decontamination of entrained radioactivity within concrete media

A phantom for the evaluation of electrokinetic remediation of radioactive species from water saturated concrete is described. The phantom has been designed to be a general analogue for environments where structural concrete is saturated by radioactive aqueous solutions and where electrokinetic remediation may be deployed. It is also a specific analogue for the walls of storage ponds for legacy spend nuclear fuel pins where the pond water comprises a large volume of hazardous active waste that may penetrate the pond wall. The fabricated phantom was evaluated using a fixed electrical potential to monitor the rate of cationic transport of K⁺ through concrete samples of different thickness (20 and 35 mm respectively). Results of the evaluation show K⁺ diffusion coefficients of 5.20 × 10^?13 and 7.61 × 10^?13 m² s^?1 for the 20 mm and 35 mm samples, consistent with those seen in literature for the transport of caesium through concrete of similar thickness. The phantom offers a means of experimental validation of computational electrokinetic models as well as providing a basis to test the effects of electrode material on ionic transport rates, to interrogate the effects of pH on all components of the system, and as a basis for instruction, education and training in nuclear decommissioning and waste treatment.     

Unusual Acetylation‐Dependent Reaction Cascade in the Biosynthesis of the Pyrroloindole Drug Physostigmine

Physostigmine is a parasympathomimetic drug used to treat a variety of neurological disorders, including Alzheimer’s disease and glaucoma. Because of its potent biological activity and unique pyrroloindole skeleton, physostigmine has been the target of many organic syntheses. However, the biosynthesis of physostigmine has been relatively understudied. In this study, we identified a biosynthetic gene cluster for physostigmine by genome mining. The 8.5 kb gene cluster encodes eight proteins (PsmA–H), seven of which are required for the synthesis of physostigmine from 5‐hydroxytryptophan, as shown by in vitro total reconstitution. Further genetic and enzymatic studies enabled us to delineate the biosynthetic pathway for physostigmine. The pathway features an unusual reaction cascade consisting of highly coordinated methylation and acetylation/deacetylation reactions.     

Stimuli‐Responsive Theragrippers for Chemomechanical Controlled Release

We report on a therapeutic approach using thermo‐responsive multi‐fingered drug eluting devices. These therapeutic grippers referred to as theragrippers are shaped using photolithographic patterning and are composed of rigid poly(propylene fumarate) segments and stimuli‐responsive poly(N‐isopropylacrylamide‐co‐acrylic acid) hinges. They close above 32 °C allowing them to spontaneously grip onto tissue when introduced from a cold state into the body. Due to porosity in the grippers, theragrippers could also be loaded with fluorescent dyes and commercial drugs such as mesalamine and doxorubicin, which eluted from the grippers for up to seven days with first order release kinetics. In an in vitro model, theragrippers enhanced delivery of doxorubicin as compared to a control patch. We also released theragrippers into a live pig and visualized release of dye in the stomach. The design of such tissue gripping drug delivery devices offers an effective strategy for sustained release of drugs with immediate applicability in the gastrointestinal tract.     

Organophosphate esters by GC–MS: An optimized method for aquatic risk assessment

Organophosphate esters used as flame retardants and plasticizers are ubiquitous contaminants in surface waters. Many studies indicate that these compounds are neurotoxicants, endocrine disruptors, and may affect reproduction and development of aquatic organisms. Thus, analytical methods that allow accurate quantification of these contaminants at environmentally relevant concentrations are desirable for risk assessment studies. In this study, a method based on solid phase extraction and gas chromatography coupled to mass spectrometry was developed for determination of organophosphate esters in river water extracts. Multivariate optimization was used to determine the best conditions for injection of larger volumes of sample in a Programmable Temperature Vaporization inlet. Furthermore, the matrix effect on the instrumental response was evaluated and compensated by association of extraction‐blank‐matched calibration and isotopically labeled focus standards. The method quantification limits ranged from 0.009 to 0.11 µg/L, staying below the predicted non‐effect concentration for the aquatic compartment for all analytes, which is a requisite for using in risk assessment studies. The method was applied to freshwater samples collected in rivers from the Sao Paulo State, Brazil, and eight out of the ten target organophosphate esters were quantified, being tris(2‐chloroisopropyl) phosphate and tris(phenyl) phosphate the most frequently detected compounds.     

Triple quadrupole mass spectrometry as applied to flame diagnostics: study of the C2H4/N2O/Ar flame

A recently developed research apparatus for characterization of low-pressure premixed flames has been developed and was used to characterize the C₂H₄/N₂O/Ar flame at 20 torr. This instrument incorporates several diagnostic techniques in one apparatus so that individual techniques can be quantitatively compared and the usable detection range (both in terms of resolution and species detection) expanded. Results discussed in this report include mass analysis by triple quadrupole mass spectrometer and temperature measurement by thermocouple. Concentration profiles in the one-dimensional flame include CO, N₂, and C₂H₄, at nominal m/z 28 as well as CO₂ and N₂O at m/z 44.     

Preparation of niobium and tantalum organoimido complexes from reactions of the pentahalides with amines: The crystal and molecular structure of bis(t-butylamine)bis(t-butylimido)bis(μ-ethoxy)tetrachloroditantalum

MCl₅ (M = Nb, Ta) reacts with 2 equivalents of Me₃SiNHCMe₃ to give [M(NCMe₃)Cl₃(NH₂CMe₃)] from which [M(NCMe₃)Cl₃(PMe₃)₂] is obtained on addition of PMe₃. One equivalent of Me₃SiNHCMe₃ reacts with MCl₅ in the presence of 3 equivalents of PMe₃ to give [M(NCMe₃)Cl₃(PMe₃)₂] and PMe₃HCl. MCl₅ reacts with excess RNH₂ (R = CMe₃, CHMe₂, CH₂Me) to give [M(NR)(NHR)Cl₂(NH₂R)] and 3 equivalents of RNH₃Cl. One equivalent of alcohol replaces the amido ligand in [M(NCMe₃)(NHCMe₃)Cl₂(NH₂CMe₃)] to give [M(NCMe₃)(OR)Cl₂(NH₂CMe₃)]₂ (M = Nb, R = OCMe₃; M = Ta, R = OEt). The structure of [Ta(NCMe₃)(μ-OEt)Cl₂(NH₂CMe₃)]₂ was determined by single-crystal X-ray diffraction methods. Crystals are triclinic, space group P$\text{1}$ with a = 9.900(5), b = 10. 161(17), c = 9.017(6) Å and α = 103.91(8), β = 97.77(4), γ = 64.40(7)°. The structure was solved by Patterson and Fourier methods and refined to an R value of 0.062 for 1319 observed data. The TaN_imido and TaN_amino bond lengths are 1.70(2) Å and 2.28(2) Å, respectively; the bridging TaO bond lengths are 2.01(2) Å and 2.32(2) Å, the longer one lying trans to the imido function.     

Wirkung von Actinomycin D auf die RNS-Synthese und die synchrone Mitosetätigkeit in Physarum polycephalum

Zusammenfassung Actinomycin D (250 /ml) hemmt in Suspensionskulturen vonPhysarum polycephalum spezifisch die RNS-Synthese, während die DNS- und Proteinsynthese innerhalb der ersten drei Stunden nur wenig beeinträchtigt werden. Die Auslösung einer synchronen Kernteilung in Makroplasmodien kann durch 250 /ml Actinomycin D verhindert oder stark verzögert werden, sofern der Hemmstoff spätestens zu Beginn des letzten Drittels der Interphase ( 2 Stdn. vor Prophase) dem Medium zugesetzt wird. Die Mitosehemmung ist durch Auswaschen des Hemmstoffes reversibel. Die Ergebnisse sprechen dafür, daß zur Vorbereitung einer Mitose während des größten Teiles der Interphase DNS-abhängige RNS neu gebildet werden muß, die möglicherweise als Informationsüberträger die Synthese mitosespezifischer Proteine kontrolliert. Es wird eine Arbeitshypothese diskutiert, nach der die Mitose als ein durch Genregulation gesteuerter Vorgang aufzufassen wäre.

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Actinomycin D (250 /ml) specifically inhibits RNA synthesis in suspension cultures ofPhysarum polycephalum whereas DNA and protein synthesis are less affected within the first three hours. Onset of synchronous mitoses in macroplasmodia is prohibited or largely delayed by 250 /ml actinomycin D if the inhibitor is added to the medium at or prior to the beginning of the last third of interphase ( 2 hrs. prior to prophase). Removal of the inhibitor from the medium reverses the inhibitory effect on mitosis. The results indicate that preparation of mitosis requires synthesis of DNA dependent RNA during the major part of interphase. These RNA molecules possibly carry information for the synthesis of proteins specifically involved with mitosis. A working hypothesis is discussed suggesting that mitotic activities may by controlled by gene regulation.

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Mit 4 Abbildungen

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Herrn Prof. Dr.Hermann Bretschneider zum 60. Geburtstag gewidmet.     

Organo-imido alkoxides of tungsten(VI). The crystal and molecular structures of [W(NPh)(μ-OMe)(OMe)3]2 and [W(NPh)(OCMe3)3Cl(NH2CMe3)]

Reaction of phenylimido tungsten tetrachloride with MeOH and t-butylamine gave the dimeric complexes [W(NPh)(μ-OMe)(OMe)₃]₂ and [W(NPh)(μ-OMe)(OMe)₂Cl]₂. With ethanol [W(NPh)(μ-OEt)(OEt)₂Cl]₂ was formed whereas isopropyl and neopentyl alcohols gave the monomeric complexes [W(NPh)(OR)₄(NH₂CMe₃)](R = CHMe₂, CH₂CMe₃); t-butanol gave [W(NPh)(OCMe₃)3Cl(NH₂CMe₃)] which could not be converted to [W(NPh) (OCMe₃)₄]. Further reaction of [W(NPh)(μ-OMe)(OMe)₃]₂ with o-HOC₆H₄CH = NC₆H₃Me₂(salim-H) gave the salicylaldimine complex [W(NPh)(OMC)₃(salim)]. The products were characterised by analytical data, IR, ¹H NMR, ¹³C NMR and mass spectroscopy. The crystal and molecular structures of the title complexes have been determined from single crystal X-ray diffractometer data. Crystals of [W(NPh)(μ-OMe)(OMe)₃]₂are triclinic with a = 8.473(7), b = 10.776(5), c = 7.683(Å, α = 102.26(3), β = 102.68(4), γ = 71.13(6)°, space group P$\text{1}$ Crystals of 3) [W(NPh)(OCMe₃)₃Cl(NH₂CMe₃) are monoclinic with a = 9.341(2), b = 29.608(7), c = 10.257(2) Å, β = 106.28(2)°, space group, P2₁/c. Both structures were solved by Patterson and Fourier methods and refined to R = 0.075 for the 1022 observed data of [W(NPh) (μ-OMe)(OMe)₃]₂ and to R = 0.074. For the 2033 observed data of [W(NPh)(OCMe₃)₃Cl(NH₂CMe₃). The former molecule is shown to be a dimer, the two halves of the molecule being related by a centre of symmetry. Both W atoms adopt a distorted octahedral coordination geometry and they are linked by two methoxy bridges. Trans to one of the bridging donors is the phenyl imido group with a WN bond length of 1.61(4) Å; the remaining coordination sites are filled with methoxy groups. The structure of W(NPh)(OCMe₃)₃ Cl(NH₂CMe₃) is monomeric with the phenylimido group trans to the NH₂CMe₃ ligand in a distorted octahedral coordination geometry. Remaining sites are filled with the chloride and 3 OCMe₃ ligands. The WN (imido) bond length is 1.71(2) Å, whilst WN(amine) is 2.40(2) Å