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Invited for this month's cover are researchers from the Naval Air Warfare Center Weapons Division (USA). The cover picture shows the elusive symmetric molecule bis(tetrahydrofurfuryl) ether (BTHFE) in the making. For more details, read the full text of the Communication at 10.1002/open.201600013.

The Front Cover picture shows crude bis(tetrahydrofurfuryl) ether (BTHFE) before the final fractional distillation. This work demonstrates a synthetic method that allows for tetrahydrofurfuryl ethers with bulky substituents to be produced. The chemical and physical properties of BTHFE make it an interesting compound for use in electrochemical energy storage devices. More information can be found in the Communication by P. A. Goodman and co‐workers on page 297 in Issue 4, 2016 (DOI: 10.1002/open.201600013).

The guidelines of the Society for Vascular Surgery and the American Venous Forum for management of patients with varicose veins recommend at level 1B endovenous thermal ablation for treatment of saphenous incompetence. High ligation and stripping is recommended only at level 2B. Consequently today most of the surgical procedures in the US are done endoluminally. The situation in Germany is different. The vast majority of the over 300,000 procedures done annually for varicose veins are surgical. In specialized centers in Germany, post-operative failures after high ligation are uncommon. Improper operative approaches seem likely in many of the randomized controlled trials (RCT). After proper high ligation, the results are very good.

Poly(ethylene oxide) (PEO) and poly[oxymethylene-oligo(oxyethylene)](PEM) disks are cross-linked by exposure to UV radiation. The rate of formation of cross-links is greatly enhanced by the presence of benzophenone, and an average cross-link density of up to 6 mol% of ethoxy units can be obtained after irradiation. The highly cross-linked polymers are insoluble in water or organic solvents and show improved physical properties for handling and the formation of free-standing films. Dynamic modulus measurements and polymer swelling are employed to characterize the polymers. Dynamic modulus measurements show that, upon irradiation, PEO and PEM become cross-linked elastomeric solids.

A new main-chain syndioregic (head-to-head) NLO polymer was synthesized. The glass transition temperature of high molecular weight polymer was found to be 208°C, and the polymer has minimal weight loss at temperatures to at least 250°C owing to the incorporation of hydrogen bonding moieties and rigid bridging groups. The polymer was further characterized using nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The study of the nonlinear optical properties of this polymer are in progress. © 1993 John Wiley & Sons, Inc.

In the 1:1 radical cation salt, (trans-1,2-bis(2-naphthyl)ethene)SbF6, the naphthalene stacks of the corresponding 2:1 stoichiometric naphthalene salt are chemically bridged. The magnetic properties of this new organic semiconductor are analysed. The role of defects related to the disordered crystal structure and the influence of sample ageing have been discerned.

A single-crystal radical cation salt was obtained by anodic oxidation of trans-1,2-bis-(2-naphthyl)ethene (1,2-DNE) with SbF−6 as the counter-ion. The crystal structure of (1,2-DNE)SbF6 was solved and found to be similar to the radical cation salts of unsubstituted naphthalene. The crystal structure is disordered, i.e. two orientations of the 1,2-DNE molecules are statistically occupied. The molecular overlap, resulting from these two orientations, models the structure of the salt of poly(2,6-naphthylenevinylene). In contrast to most other radical cation salts which are one-dimensional conductors, a conduction mechanism of higher dimensionality is predicted on the basis of the crystal structure of (1,2-DNE)SbF6. The identical type of disorder is also present in the crystal structure of trans-1,2-bis(1-naphthyl)ethene.

Poly[(4-N-ethylene-N-ethylamino)-α-cyanocinnamate] was prepared by solution esterification of (4-N-ethyl-N-(2-hydroxyethyl) amino)-α-Cyanocinnamic acid and by melt transesterification of ethyl (4-N-ethyl-N-(2-hydroxyethyl) amino)-α-cyanocinnamate. The melt transesterification generally yielded polymer with a number-average molecular weight of about 10,200 by gel permeation chromatography (GPC) versus polystyrene standards. The polymer was found to be amorphous with a glass transition temperature of about 103°C by differential scanning calorimetry (DSC). The solution esterification generally gave a polymer with a number-average molecular weight of about 2200 by GPC versus polystyrene standards. This polymer was found to have a glass transition temperature varying between 60 and 90°C by DSC. The infrared (IR) spectrum of the polymer made from both methods were analyzed in detail. The 1H- and 13C-NMR spectra of the meltsynthesized ethyl cinnamate derivative polymer are consistent with the reported structure.

Films of poly(1,4-naphthalene vinylene) (P-1,4-NV) were obtained by the thermal elimination of a cycloalkylene sulphonium salt precursor polymer. The ultra-violet/visible (u.v./vis.), fluorescence and Raman spectra and the small-angle X-ray scattering diagrams were examined, and the oxidation and reduction potentials of P-1,4-NV were determined by cyclic voltammetry. The u.v./vis. spectra of P-1,4-NV films made from a sulphonium salt polymer based on the cyclic sulphide, tetrahydrothiophene, which was converted to P-1,4-NV at a temperature about 30°C lower than the temperature needed to obtain P-1,4-NV from the dimethylsulphide sulphonium salt polymer, showed phonon sidebands at room temperature as well as at −200°C. The phonon sidebands were apparently associated with a narrow distribution of crystallite sizes, which had an average long-period spacing of 140A, and was obtained when P-1,4-NV was made from the cyclic sulphonium chloride precursor polymer. The oxidation potential was found to be 0.75 V vs. SCE (saturated calomel electrode), the reduction potential was found to be −1.60V vs. SCE and the band-gap energy was found to be around 2.05V. The high value for the oxidation potential of P-1,4-NV, in comparison to the oxidation potential of triiodide (0.52V vs. SCE), from which an approximate value of 2 × 10 −8 for the oxidation equilibrium constant was obtained, explains why very low conductivities are obtained when P-1,4-NV is doped with iodine. Films of the cycloalkylene sulphonium salt precursor polymer could be drawn to as much as 1.6 times their original length, and the drawn films showed a significant degree of orientation according to X-ray diffraction and polarized infra-red spectroscopy.

Le polymere [CH 2 CH 2 N(Et) PhCH=CHC(CN)CO 2 ] 4 prepare par polycondensation de l'acide ou de l'ester correspondant est soluble dans les solvants usuels. Les mesures de generation de seconde harmonique donnent pour les films de polyester une valeur de 7±1,4 pm/V pour d 33

We explore a number of polymer architectures with the objective of fabricating intrinsically polar polymer films for applications such as electro-optic switches and signal modulators for high bandwidth data processing. The goal of this work is to offer an alternative to the poled polymer approach in order to avoid high temperature processing and high electric fields. This paper reports progress toward achieving this goal.

An 11-year-old girl presented with recurrent vomiting, reduced food and fluid intake, weight loss and dizziness. In an external hospital she was diagnosed as having habitual vomiting and a beginning eating disorder. The physical examination revealed a very thin, malnourished child with abdominal pain on palpation but without neurologic deficits. Laboratory findings, X-rays, endoscopy and ultrasound revealed no pathological results either. Since the EEG and the cranial computed tomography (CT) were normal, we also suspected the beginning of an eating disorder especially due to some psychical peculiarities. The MRI which was done for ultimate exclusion of an infratentorial tumor showed a well defined displacing structure in the dorsal medulla oblongata and in the upper cervical spinal cord. A corresponding prolongation of the central conduction time was found in the median nerve SSEP whereas the BAEPs were normal. The tumor was excised in toto and the histological examination confirmed the suspected diagnosis of cavernous hemangioma (cavernoma). The post operative phase was without any complications and the intiated nutrition was well tolerated. Neurological deficits were not observed.

The accordion polymer [CH 2 N(C 16 H 33 )PhCH=C(CN)CONHCH 2 CHOHCH 2 NHCOC(CN)=CHPhN(C 16 H 33 )CH 2 ] n is prepared by a Knoevenagel polycondensation. The Y-type multilayer of this polymer gave no second harmonic generation, which was not unexpected, because the dipole in adjacnet layers should be pointing in opposite direction