Case study: cochlear implantation in cochlear otospongiosis.

Objective and importance: Cochlear implantation can be performed successfully in patients with otospongiosis of the temporal bone with the potential for excellent audiological outcomes and high patient satisfaction. The purpose of this case report is to highlight the clinical considerations for implantation in cochlear otospongiosis including the need for careful pre-operative implant device selection, intra-operative surgical challenges such as the presence of hypervascularity and possible cochlear ossification resulting in difficulty in placing the electrode array and the possibility of postoperative facial nerve stimulation.Clinical presentation: A 14-year-old girl with cochlear otospongiosis likely due to osteogenesis imperfecta presented with progressive bilateral profound sensorineural hearing loss underwent successful cochlear implantation despite several challenges.Conclusion: Cochlear implantation in patients with cochlear otospongiosis with profound sensorineural hearing loss potentially may be very successful. Thorough pre-operative radiological evaluation is necessary. Possible intra-operative and post-operative challenges unique to these patients must be kept in mind. Adequate precautions should be taken to optimize the likelihood of complete electrode insertion such as using a depth gauge prior to inserting the electrode array and performing an intra-operative x-ray and / or neural response telemetry to confirm correct electrode placement.

The Economic Value of Long-Lasting Insecticidal Nets and Indoor Residual Spraying Implementation in Mozambique.

AbstractMalaria-endemic countries have to decide how much of their limited resources for vector control to allocate toward implementing long-lasting insecticidal nets (LLINs) versus indoor residual spraying (IRS). To help the Mozambique Ministry of Health use an evidence-based approach to determine funding allocation toward various malaria control strategies, the Global Fund convened the Mozambique Modeling Working Group which then used JANUS, a software platform that includes integrated computational economic, operational, and clinical outcome models that can link with different transmission models (in this case, OpenMalaria) to determine the economic value of vector control strategies. Any increase in LLINs (from 80% baseline coverage) or IRS (from 80% baseline coverage) would be cost-effective (incremental cost-effectiveness ratios ≤ $114/disability-adjusted life year averted). However, LLIN coverage increases tend to be more cost-effective than similar IRS coverage increases, except where both pyrethroid resistance is high and LLIN usage is low. In high-transmission northern regions, increasing LLIN coverage would be more cost-effective than increasing IRS coverage. In medium-transmission central regions, changing from LLINs to IRS would be more costly and less effective. In low-transmission southern regions, LLINs were more costly and less effective than IRS, due to low LLIN usage. In regions where LLINs are more cost-effective than IRS, it is worth considering prioritizing LLIN coverage and use. However, IRS may have an important role in insecticide resistance management and epidemic control. Malaria intervention campaigns are not a one-size-fits-all solution, and tailored approaches are necessary to account for the heterogeneity of malaria epidemiology.

Coupling of propylene oxide and lactide at a porphyrin chromium(III) center.

5,10,15,20-Tetraphenylporphyrin chromium chloride (TPPCrCl) with added [Ph3P═N═PPh3](+)Cl(-) (PPN(+)Cl(-)) selectively polymerizes lactide (L and rac) dissolved in neat propylene oxide (PO) to yield polylactide (PLA) terminated by the -OCHMeCH2Cl group. At 0 °C and below, rac-LA yields polymers highly enriched in isotactic tetrads (iii). At 25 °C, some stereoselectivity is lost as transesterification becomes significant, and at 60 °C and above, enchainment of PO leads to the formation of 3,6-dimethyl-1,4-dioxan-2-one by a backbiting mechanism. At 0 °C, after the enchainment of L-(S,S)-LA in neat (R)-(+)-PO, the formation of (3S,6R)-3,6-dimethyl-1,4-dioxan-2-one occurs, while at higher temperatures the ratio of (3S,6R)-3,6-dimethyl-1,4-dioxan-2-one to (3R,6R)-3,6-dimethyl-1,4-dioxan-2-one falls to 3:2.

Ring-opening polymerization reactions of propylene oxide catalyzed by porphyrin metal 3+ complexes of aluminum, chromium and cobalt.

In today's world, a major scientific challenge is preserving the delicate balance between industrial growth and a pollutant free terrestrial environment. Thus, "greener" syntheses of commodity materials, capture and utilization of gaseous industrial by-products have become research areas of increasing significance. The pioneering work of Inoue showed a potential utilization of CO2, a major petrochemical by-product, and opened a new field of research. Inoue discovered the (porphyrin)Al(III)X catalyst systems, (X=Cl(-) or alkoxide) which copolymerize CO2 with epoxides to produce polycarbonates. This catalyst can also copolymerize epoxides and cyclic anhydrides to form polyesters. The current record describes our research aimed towards mechanistic understanding and further developments of (porphyrin)M(III)X catalyst systems. This detailed account shows the influence of the porphyrin ligands (tetraphenylporphyrin (TPP), octaethylporphyrin (OEP), tetrakis-pentafluorophenylporphyrin (TFPP)), metal centers (Al, Cr, and Co) and Lewis base co-catalysts on the individual reaction steps and equilibria involved in the copolymerization processes.

Influence of the metal (Al, Cr, and Co) and substituents of the porphyrin in controlling reactions involved in copolymerization of propylene oxide and carbon dioxide by porphyrin metal(III) complexes. 3. Cobalt chemistry.

A series of cobalt(III) complexes LCoX, where L = 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP), and 2,3,7,8,12,13,17,18-octaethylporphyirn (OEP) and X = Cl or acetate, has been investigated for homopolymerization of propylene oxide (PO) and copolymerization of PO and CO2 to yield polypropylene oxide (PPO) and polypropylene carbonate (PPC) or propylene carbonate (PC), respectively. These reactions were carried out both with and without the presence of a cocatalyst, namely, 4-dimethylaminopyridine (DMAP) or PPN(+)Cl(-) (bis(triphenylphosphine)iminium chloride). The PO/CO2 copolymerization process is notably faster than PO homopolymerization. With ionic PPN(+)Cl(-) cocatalyst the TPPCoOAc catalyst system grows two chains per Co center and the presence of excess [Cl(-)] facilitates formation of PC by two different backbiting mechanisms during copolymerization. Formation of PPC is dependent on both [Cl(-)] and the CO2 pressure employed (1-50 bar). TPPCoCl and PO react to form TPPCo(II) and ClCH2CH(Me)OH, while with DMAP, TPPCoCl yields TPPCo(DMAP)2(+)Cl(-). The reactions and their polymers and other products have been monitored by various methods including react-IR, FT-IR, GPC, ESI, MALDI TOF, EXAFS, and NMR ((1)H, (13)C{(1)H}) spectroscopy. Notable differences are seen in these reactions with previous studies of (porphyrin)M(III) complexes (M = Al, Cr) and of the (salen)M(III) complexes where M = Cr, Co.

Influence of the metal (Al, Cr, and Co) and the substituents of the porphyrin in controlling the reactions involved in the copolymerization of propylene oxide and carbon dioxide by porphyrin metal(III) complexes. 2. Chromium chemistry.

The reactivities of chromium(III) complexes LCrX, where L = 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP), and 2,3,7,8,12,13,17,18-octaethylporphyrin (OEP) and X = Cl or OH, have been studied with respect to their ability to homopolymerize propylene oxide (PO) and copolymerize PO and CO(2) to yield polypropylene oxide (PPO) and polypropylene carbonate (PPC) or propylene carbonate (PC), respectively, with and without the presence of a cocatalyst, namely, 4-dimethylaminopyridine (DMAP) or PPN(+)Cl(-) (bis(triphenylphosphine)iminium chloride). The homopolymerization is notably faster (TOF ≈ 2000 h(-1) at room temperature) than copolymerization, which commonly leads to ether-rich polymers. Studies of kinetics reveal that for TPPCr(OH) with DMAP (1 equiv) the propagation reaction rate is first order in [Cr] with excess PO. With PPN(+)Cl(-) as a cocatalyst the reaction order in [Cr] and [Cl(-)] is complicated by the presence of two growing chains, and the presence of excess [Cl(-)] facilitates the formation of PC by two different backbiting mechanisms. The fixation of CO(2) is promoted by [Cl(-)] but is not greatly influenced by CO(2) pressure (1-50 bar). The reactions and polymers have been monitored by UV-visible spectroscopy, react-IR, GPC, ESI, and MALDI TOF, and NMR ((1)H, (13)C{(1)H}) spectroscopy. Notable differences are seen in these reactions when compared with earlier studies by Darensbourg et al. with salen chromium(III) systems and related aluminum(III) porphyrins.

The influence of the metal (Al, Cr, and Co) and the substituents of the porphyrin in controlling the reactions involved in the copolymerization of propylene oxide and carbon dioxide by porphyrin metal(III) complexes. 1. Aluminum chemistry.

The reactivities of aluminum(III) complexes LAlX, where L = 5,10,15,20-tetraphenylporphyrin (TPP), 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP), and 2,3,7,8,12,13,17,18-octaethylporphyirn (OEP) and X = Cl or OEt, have been studied with respect to their ability to homopolymerize propylene oxide (PO) and copolymerize PO and CO(2) to yield polypropylene oxide (PPO) and polypropylene carbonate (PPC), respectively, with and without the presence of a cocatalyst, namely, 4-dimethylaminopyridine (DMAP) or a PPN(+) salt where the anion is Cl(-) or N(3)(-). In the presence of a cocatalyst (0.5 equiv), the TFPP complex is the most active in copolymerization to yield PPC, with the latter being effective even at 10 bar CO(2). An increase in the PPN(+)X(-)/[Al] ratio decreases the rate of PPC formation and favors the formation of propylene carbonate, (PC). Studies of the polymers formed in reactions involving Al-alkoxide initiators and PPN(+) salts by mass spectrometry indicate that one chain is grown per Al center. These results are compared with earlier studies where the reactions display first order kinetics in the metal complex.