Functionalization of Pentaphosphorus Cations by Complexation.

The chemistry of polyphosphorus cations has rapidly developed in recent years, but their coordination behavior has remained mostly unexplored. Herein, we describe the reactivity of [P5 R2 ]+ cations with cyclopentadienyl metal complexes. The reaction of [CpAr Fe(µ-Br)]2 (CpAr =C5 (C6 H4 -4-Et)5 ) with [P5 R2 ][GaCl4 ] (R=iPr and 2,4,6-Me3 C6 H2 (Mes)) afforded bicyclo[1.1.0]pentaphosphanes (1-R, R=iPr and Mes), showing an unsymmetric "butterfly" structure. The same products 1-R were formed from K[CpAr ] and [P5 R2 ][GaCl4 ]. The cationic complexes [CpAr Co(η4 -P5 R2 )][GaCl4 ] (2-R[GaCl4 ], R=iPr and Cy) and [(CpAr Ni)2 (η3:3 -P5 R2 )][GaCl4 ] (3-R[GaCl4 ]) were obtained from [P5 R2 ][GaCl4 ] and [CpAr M(µ-Br)]2 (M=Co and Ni) as well as by using low-valent "CpAr MI " sources. Anion metathesis of 2-R[GaCl4 ] and 3-R[GaCl4 ] was achieved with Na[BArF24 ]. The P5 framework of the resulting salts 2-R[BArF24 ] can be further functionalized with nucleophiles. Thus reactions with [Et4 N]X (X=CN and Cl) give unprecedented cyano- and chloro-functionalized complexes, while organo-functionalization was achieved with CyMgCl.

Core-Shell Structuring of Pure Metallic Aerogels towards Highly Efficient Platinum Utilization for the Oxygen Reduction Reaction.

The development of core-shell structures remains a fundamental challenge for pure metallic aerogels. Here we report the synthesis of Pdx Au-Pt core-shell aerogels composed of an ultrathin Pt shell and a composition-tunable Pdx Au alloy core. The universality of this strategy ensures the extension of core compositions to Pd transition-metal alloys. The core-shell aerogels exhibited largely improved Pt utilization efficiencies for the oxygen reduction reaction and their activities show a volcano-type relationship as a function of the lattice parameter of the core substrate. The maximum mass and specific activities are 5.25 A mgPt-1 and 2.53 mA cm-2 , which are 18.7 and 4.1 times higher than those of Pt/C, respectively, demonstrating the superiority of the core-shell metallic aerogels. The proposed core-based activity descriptor provides a new possible strategy for the design of future core-shell electrocatalysts.

Modern Inorganic Aerogels.

Essentially, the term aerogel describes a special geometric structure of matter. It is neither limited to any material nor to any synthesis procedure. Hence, the possible variety of materials and therefore the multitude of their applications are almost unbounded. In fact, the same applies for nanoparticles. These are also just defined by their geometrical properties. In the past few decades nano-sized materials have been intensively studied and possible applications appeared in nearly all areas of natural sciences. To date a large variety of metal, semiconductor, oxide, and other nanoparticles are available from colloidal synthesis. However, for many applications of these materials an assembly into macroscopic structures is needed. Here we present a comprehensive picture of the developments that enabled the fusion of the colloidal nanoparticle and the aerogel world. This became possible by the controlled destabilization of pre-formed nanoparticles, which leads to their assembly into three-dimensional macroscopic networks. This revolutionary approach makes it possible to use precisely controlled nanoparticles as building blocks for macroscopic porous structures with programmable properties.

Shape-controlled synthesis of gold nanostructures using DNA origami molds.

We introduce a new concept that allows the synthesis of inorganic nanoparticles with programmable shape. Three-dimensional DNA origami nanostructures harboring an internal cavity are used as molds. A small gold nanoparticle within the cavity nucleates solution-based gold deposition leading to mold filling. We demonstrate the fabrication of 40 nm long rodlike gold particles with quadratic cross section and the formation of higher order assemblies of the obtained particles, which is mediated by their DNA shell.

Day-to-day reliability of two different models to quantify knee kinematics in subjects with knee osteoarthritis and healthy controls.

Results from instrumented gait analysis vary between test situations. Subject characteristics and the biomechanical model can influence the total amount of variability. The purpose of this study was to quantify reliability of gait data in general, and with respect to the applied model, and investigated population group. Reliability was compared between a functional and a predictive gait model in subjects with knee osteoarthritis and healthy controls. Day-to-day consistency for sagittal plane variables was comparable between models and population groups. Transversal plane variables relative to joint excursion showed larger inconsistency for repeated measures, even for a more sophisticated biomechanical approach. In conclusion, the presented reliability data of sagittal plane kinematics should be used for a reasonable interpretation of results derived in clinical gait analysis. Variables of the transversal plane should not be used as long as sources of error are not sufficiently minimized.

Synthesis and Characterization of Bidentate Isonitrile Iron Complexes.

The divalent iron complexes trans-[FeBr2(BINC)2], [Cp*FeCl(BINC)] (Cp* = Me5C5), and [FeBr2(CNAr3NC)2] with the chelating bis(isonitrile) ligands BINC (bis(2-isocyanophenyl)phenylphosphonate) and CNAr3NC (2,2″-diisocyano-3,5,3″,5"tetramethyl-1,1':3',1″-terphenyl) have been prepared and characterized. Their subsequent reduction yields the di- and trinuclear compounds [Fe3(BINC)6], [Cp*Fe(BINC)]2, [Fe(CNAr3NC)2]2, and [K(Et2O)]2[Fe(CNAr3NC)2]2. The molecular structures of all new species were determined by X-ray crystallography and compared to those of related iron carbonyl complexes, demonstrating that the bidentate isonitrile ligands are capable surrogates for two CO ligands with only minimal distortion of the tetrahedral or octahedral geometry of the parent complexes. The complexes were further characterized by NMR and IR spectroscopy, and the electrochemical properties of selected compounds were analyzed by UV-vis-NIR spectroelectrochemistry.

The route to functional graphene oxide.

We report on an easy-to-use, successful, and reproducible route to synthesize functionalized graphite oxide (GO) and its conversion to graphene-like materials through chemical or thermal reduction of GO. Graphite oxide containing hydroxyl, epoxy, carbonyl, and carboxyl groups loses mainly hydroxyl and epoxy groups during reduction, whereas carboxyl species remain untouched. The interaction of functionalized graphene with fluorescent methylene blue (MB) is investigated and compared to graphite, fully oxidized GO, as well as thermally and chemically reduced GO. Optical absorption and emission spectra of the composites indicate a clear preference for MB interaction with the GO derivatives containing a large number of functional groups (GO and chemically reduced GO), whereas graphite and thermally reduced GO only incorporate a few MB molecules. These findings are consistent with thermogravimetric, X-ray photoelectron spectroscopic, and Raman data recorded at every stage of preparation. The optical data also indicate concentration-dependent aggregation of MB on the GO surface leading to stable MB dimers and trimers. The MB dimers are responsible for fluorescence quenching, which can be controlled by varying the pH value.

Analgesic effects of intra-articular morphine in patients with temporomandibular joint disorders: a prospective, double-blind, placebo-controlled clinical trial.

PURPOSE: A number of reports have shown a direct analgesic effect of opioids by way of the peripheral receptors. Nevertheless, only a very few studies have reported using opioids in the temporomandibular joint (TMJ), and nearly all of them were connected to surgical patient groups. The present study was designed to evaluate the analgesic efficacy and safety of repeated intra-articular morphine applications compared with a local anesthetic and saline solution in the management of TMJ pain. PATIENTS AND METHODS: A total of 48 patients with articular pain related to the TMJ were entered in a clinical, prospective, randomized, double-blind, single-center study. The analgesic effect of repeated intra-articular infiltration with morphine (5 or 10 mg morphine sulfite), bupivacaine 0.5% (Carbostesin; AstraZeneca, London, UK), and isotonic saline solution as a placebo in the TMJ was examined. The efficiency after 3 injections of the same substance with an interval of 48 hours between each application was measured using a pain relief scale, visual analog scale, pain intensity scale, and the potential need for accessory peripheral analgesics (paracetamol). RESULTS: All patients showed, independent of the treatment group, pain relief within 60 minutes after the first injection. Patients with saline and Carbostesin reported almost complete pain recurrence before the second injection. At 1 week after the last and third injection, the 10-mg morphine group still showed a distinct effect, with 16.7% reporting complete (no pain) and 41.7% distinct pain relief. In addition, 33.3% had a poor response and 8.3% had no improvement. None of the other groups reported complete improvement; however, 25% of the patients who received 5 mg morphine had distinct pain relief, and 50% had at least poor pain relief. In the Carbostesin group, distinct improvement was reported by 8.3%, with a poor response in 41.7%, and no effect in the remaining 50%. Patients treated with saline had a poor response in 16.7%, but most (83.3%) reported no improvement 1 week after treatment. CONCLUSIONS: Independent of the applied substances, initial pain relief can be registered in the TMJ: either from the arthrocentesis effect or at least the placebo effect. Morphine at a dosage of 10 mg showed the best and most long-lasting analgesic efficiency. Morphine, in general (5 and 10 mg), and, with limitations, Carbostesin were more or less efficient for postoperative pain control but without distinct effects in the long term. With regard to our results, we can recommend intra-articular morphine application at a dose of 10 mg for pain management. Carbostesin showed no promising long-term effects.

Iron-Gallium and Cobalt-Gallium Tetraphosphido Complexes.

The synthesis and characterization of two heterobimetallic complexes [K([18]crown-6){(η4-C14H10)Fe(µ-η4:η2-P4)Ga(nacnac)}] (1) (C14H10 = anthracene) and [K(dme)2{(η4-C14H10)Co(µ-η4:η2-P4)Ga(nacnac)}] (2) with strongly reduced P4 units is reported. Compounds 1 and 2 are prepared by reaction of the gallium(III) complex [(nacnac)Ga(η2-P4)] (nacnac = CH[CMeN(2,6-iPr2C6H3)]2) with bis(anthracene)ferrate(1-) and -cobaltate(1-) salts. The molecular structures of 1 and 2 were determined by X-ray crystallography and feature a P4 chain which binds to the transition metal atom via all four P atoms and to the gallium atom via the terminal P atoms. Multinuclear NMR studies on 2 suggest that the molecular structure is preserved in solution.

An unusual Ni2Si2P8 cluster formed by complexation and thermolysis.

[LSi(η2-P4)] (L = CH[C(Me)N(Dipp)][C(CH2)N(Dipp)], Dipp = 2,6-diisopropylphenyl) forms well-defined 1 : 1 and 2 : 1 complexes with N-heterocyclic carbene nickel fragments. The cluster compound [(IDipp)Ni2P8(SiL)2] (IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) is selectively formed by thermolysis of the complex [(IDipp)Ni(µ-η2:2-P4)SiL].

Construction of alkyl-substituted pentaphosphido ligands in the coordination sphere of cobalt.

Rare mono- and diorganopentaphosphido cobalt complexes are accessible by P-P condensation using the unprecedented, reactive cobalt-gallium tetraphosphido complex [K(dme)2{(MesBIAN)Co(µ-η4:η2-P4)Ga(nacnac)}] (2). Compound 2 was prepared in good yield by reaction of [K(Et2O){(MesBIAN)Co(η4-1,5-cod)}] [1, BIAN = bis(mesitylimino)acenaphthene diimine, cod = 1,5-cyclooctadiene] with [Ga(nacnac)(η2-P4)] (nacnac = CH[CMeN(2,6-iPr2C6H3)]2). Reactions with R2PCl (R = iPr, tBu, and Cy) selectively afford [(MesBIAN)Co(cyclo-P5R2)] (3a-c), which feature η4-coordinated 1,1-diorganopentaphosphido ligands. The mechanism of formation of these species has been studied by 31P{1H} NMR spectroscopy and DFT calculations. In the case of 3a (R = iPr), it was possible to identify the intermediate [(MesBIAN)Co(µ-η4:η2-P5iPr2)Ga(nacnac)] (4) by single-crystal X-ray diffraction. A related, monosubstituted organopentaphosphido cobalt complex [(MesBIAN)Co(µ-η4:η1-P5 tBu)GaCl(nacnac)] (5) was isolated by reacting dichloroalkylphosphane tBuPCl2 with 2. Heterobimetallic complexes such as 2 thus may enable the targeted construction of a range of new metal-coordinated polyphosphorus frameworks by P-P condensation.

Current concepts in cleft care: A multicenter analysis.

The current surgical techniques used in cleft repair are well established, but different centers use different approaches. To determine the best treatment for patients, a multi-center comparative study is required. In this study, we surveyed all craniofacial departments registered with the German Society of Maxillofacial Surgery to determine which cleft repair techniques are currently in use. Our findings revealed much variation in cleft repair between different centers. Although most centers did use a two-stage approach, the operative techniques and timing of lip and palate closure were different in every center. This shows that a retrospective comparative analysis of patient outcome between the participating centers is not possible and illustrates the need for prospective comparative studies to establish the optimal technique for reconstructive cleft surgery.

A large ameloblastic fibro-odontoma of the right mandible.

The ameloblastic fibro-odontoma is a rare mixed odontogenic tumor. It occurs predominantly in children and young adults with no sex predilection and locates most often in the posterior segment of the mandible. A painless swelling is the most common clinical sign. Radiologically, ameloblastic fibro-odontoma shows a circumscribed radiolucency, which contains radio-opaque foci of various sizes and shapes. Histological examination reveals a fibrous soft tissue, islands of odontogenic epithelium and a disordered mixture of dental tissues. The tumor produces enamel or enamel matrix, dentin and cementum. The treatment of ameloblastic fibro-odontomas usually consists of enucleation or surgical curettage, which is possible due to their benign biological behaviour.

Absolute Energy Level Positions in CdSe Nanostructures from Potential-Modulated Absorption Spectroscopy (EMAS).

Semiconductor nanostructures such as CdSe quantum dots and colloidal nanoplatelets exhibit remarkable optical properties, making them interesting for applications in optoelectronics and photocatalysis. For both areas of application a detailed understanding of the electronic structure is essential to achieve highly efficient devices. The electronic structure can be probed using the fact that optical properties of semiconductor nanoparticles are found to be extremely sensitive to the presence of excess charges that can for instance be generated by means of an electrochemical charge transfer via an electrode. Here we present the use of EMAS as a versatile spectroelectrochemical method to obtain absolute band edge positions of CdSe nanostructures versus a well-defined reference electrode under ambient conditions. In this, the spectral properties of the nanoparticles are monitored with respect to an applied electrochemical potential. We developed a bleaching model that yields the lowest electronic state in the conduction band of the nanostructures. A change in the band edge positions caused by quantum confinement is shown both for CdSe quantum dots and for colloidal nanoplatelets. In the case of CdSe quantum dots these findings are in good agreement with tight binding calculations. The method presented is not limited to CdSe nanostructures but can be used as a universal tool. Hence, this technique allows the determination of absolute band edge positions of a large variety of materials used in various applications.

Cold Flow as Versatile Approach for Stable and Highly Luminescent Quantum Dot-Salt Composites.

Since the beginning of the 1980s, colloidally synthesized quantum dots (QDs) have been in the focus of interest due to their possible implementation for color conversion, luminescent light concentrators, and lasing. For all these applications, the QDs benefit from being embedded into a host matrix to ensure stability and usability. Many different host materials used for this purpose still have their individual shortcomings. Here, we present a universal, fast, and flexible approach for the direct incorporation of a wide range of QDs into inorganic ionic crystals using cold flow. The QD solution is mixed with a finely milled salt, followed by the removal of the solvent under vacuum. Under high pressure (GPa), the salt powder loaded with QDs transforms into transparent pellets. This effect is well-known for many inorganic salts (e.g., KCl, KBr, KI, NaCl, CsI, AgCl) from, e.g., sample preparation for IR spectroscopy. With this approach, we are able to obtain strongly luminescent QD-salt composites, have precise control over the loading, and provide a chemically robust matrix ensuring long-term stability of the embedded QDs. Furthermore, we show the photo-, chemical, and thermal stability of the composite materials and their use as color conversion layers for a white light-emitting diode (w-LED). The method presented can potentially be used for all kinds of nanoparticles synthesized in organic as well as in aqueous media.

The current state of facial prosthetics ­ A multicenter analysis.

Even though modern surgical techniques are dominating reconstructive facial procedures, the capability to use facial epitheses for reconstruction is still an important skill for the maxillofacial surgeon. We present an international multicenter analysis to clarify which techniques are used to fixate facial prostheses. We contacted all maxillofacial departments in Germany, Austria, Switzerland and Norway which were registered with the German society for oral and maxillofacial surgery (DGMKG). These centers were asked via electronical mail to provide information on the type of epithesis fixation systems currently in use. The return rate from 58 departments was 43.1% (n = 25). Overall, implant fixation was the preferred fixation system (92%). Plates were the second most common fixation technique (32%). No centers reported the standard use of non-invasive fixation techniques for permanent epithesis fixation. The main retention systems in use were magnets (24/25), other retention systems are used much less often. The current preferred fixation technique for facial epitheses consists of implant-based, magnet-fixated epitheses. For nasal prostheses, a plate-based, magnet-fixated system is often used.

Periodontal disease as a risk factor for ischemic stroke.

BACKGROUND AND PURPOSE: Chronic infectious diseases may increase the risk of stroke. We investigated whether periodontal disease, including periodontitis and gingivitis, is a risk factor for cerebral ischemia. METHODS: We performed a case-control study with 303 patients examined within 7 days after acute ischemic stroke or transient ischemic attack, 300 population controls, and 168 hospital controls with nonvascular and noninflammatory neurological diseases. All subjects received a complete clinical and radiographic dental examination. The individual mean clinical attachment loss measured at 4 sites per tooth served as the main indicator for periodontitis. RESULTS: Patients had higher clinical attachment loss than population (P<0.001) and hospital (P=0.010) controls. After adjustment for age, sex, number of teeth, vascular risk factors and diseases, childhood and adult socioeconomic conditions, and lifestyle factors, the risk of cerebral ischemia increased with more severe periodontitis. Subjects with severe periodontitis (mean clinical attachment loss >6 mm) had a 4.3-times-higher (95% confidence interval, 1.85 to 10.2) risk of cerebral ischemia than subjects with mild or without periodontitis (

A comparison between various radiological techniques in the localization and analysis of impacted and supernumerary teeth.

BACKGROUND AND OBJECTIVES: An increasing number of different types of commercial cone-beam computed tomography (CBCT) devices are available for three-dimensional (3D) imaging in the field of dental and maxillofacial radiology. When removing impacted or supernumerary teeth, surgical teams often operate adjacent significant anatomical structures such as nerves, vessels, adjacent teeth roots, and paranasal sinuses. It is therefore important to choose the appropriate surgical approach to avoid iatrogenic damage to the essential anatomical neighbouring structures. CBCT, also called digital volume tomography (DVT), can visualize impacted and supernumerary teeth in all standard planes, as well as multisectional 3D views. These devices have shown to be highly beneficial in the assessment of small bony lesions and maxillofacial injuries. However, it is still necessary to determine the effectiveness of such devices in the assessment of impacted and supernumerary teeth, in comparison to the conventional radiological methods of intraoral X-rays and panoramic X-rays. MATERIALS AND METHODS: During a period of 2 years, a total of 61 patients of whom majority had impacted teeth or supernumerary elements in the frontal maxillary region were studied with CBCT and treated at the St. Olavs University Hospital. Patients were referred to our Department of Oral and Maxillofacial Surgery with both conventional and digital intraoral X-rays and/or panoramic X-rays. None had any acute infections or odontogenic abscesses, and most presented with asymptomatic impacted tooth. A comparison between the preoperative conventional and the CBCT images, the resulting diagnoses, and the intraoperative findings as "gold standard" were made and recorded in a compiled scoring sheet. The objects of interest were researched with the magnification method. Each patient was identified only with a patient number. RESULTS: In contrast to the conventional X-rays, the pre-surgical evaluation with the CBCT revealed detailed imaging of significant anatomical structures and objects of interest, with highly accurate anatomical and morphologic imaging, when compared to the intraoperative findings. Furthermore, no diagnostic problems, in relation to the anatomical localization, occurred preoperatively. CONCLUSION: The CBCT provides true and precise anatomical information with high surgical predictability without distortion or artefacts, and is superior to conventional radiography. It enables more time-efficient surgeries and reduces costs and surgical complications.