Combined pars plana vitrectomy, lens removal and intraocular lens implantation for complications of diabetic retinopathy. Surgical results in 120 cases

We performed combined vitrectomy, lens removal and posterior chamber intraocular lens implantation for proliferative diabetic retinopathy in 120 eyes of 101 patients. Follow-up periods ranged from 3 to 63 months, with a mean of 17 months. Three lens removal methods were used: extracapsular cataract extraction (14 eyes), phacoemulsification and aspiration (49 eyes), and pars plana phacoemulsification (57 eyes). Preoperative rubeosis iridis or neovascular glaucoma was found in 21 eyes. Gas or temporary silicone oil tamponade was employed in 32 eyes. Surgical results were good, and the postoperative vision was finger counts or below only in 13 eyes. Thus the combined surgery proved to have no serious problems. Our results indicate two important points. (1) It is best to chose either of the following two methods for the lens surgery: phacoemulsification with continuous circular capsulorhexis, self sealing sclerocorneal incision, and in-the-bag fixation of the posterior chamber lens, or pars plana phacoemulsification leaving the anterior capsule, rub off and aspirating the lens epithelial cells, continuous circular capsulorhexis, and posterior chamber lens implantation in front of the anterior capsule from a self-sealing sclerocorneal wound. (2) It is mandatory to do complete vitrectomy and cut out the vitreous gels incarcerated in the sclerotomy site.     

Influence of Metal Ions on the Order-Disorder Transition Temperature of the Ba-M-O (M: La, Y, In, or Ga) System

Preparation of BaLa₂O₄, B_a3,Y₄O₉, B_a,In₂O₅, and Ba₃Ga₂O₆ powders and their sintering were investigated in Ar or air. These sintered bodies with perovskite-related structure were synthesized by reaction sintering, using mixed powders in the atomic ratios of Ba/La = 1, Ba/Y = 0.75, Ba/In = 1, and Ba/Ga = 1.5. The order-disorder transition temperatures of the BaLa₂O₄, Ba₃Y₄O₉, Ba₂In₂O₅, and Ba₃Ga₂O₆ sintered bodies were 270°, 350°, 880°, and 123O^oC, respectively. It was found that the temperatures were influenced by the ionic radius of cations in B sites, and the transition temperatures decreased with increasing ionic radius.     

Enzymatic production of fructose 1,6-diphosphate using crude cell extract of Bacillus stearothermophilus

The enzymatic production of fructose 1,6-diphosphate (FDP) from glucose was performed in a batch reactor and a semibatch reactor using the crude cell extract of Bacillus stearothermophilus which contains all four enzymes required for the synthesis. The experimental results of the yield and the time courses of FDP production obtained using various enzyme concentrations were in good agreement with the theoretical predictions calculated based on the differential equations including the rate equations of the four enzymes, which were determined using the purified enzymes of B. stearothermophilus.     

Control of island formation on silicon surfaces using ultra-high-vacuum scanning electron microscopy

In situ scanning electron microscopy has been used to control Au island formation on a patterned Si(111) surface with a periodic array of atomic-step bunches and holes. Liquid phase Au-Si islands were observed to redistribute on the patterned surface by annealing. The islands accumulate at a particular position of the step bunch in each pattern unit. This phenomenon is interpreted in terms of the energetic stability of a droplet on a patterned surface.     

Kinetics and reaction scheme of coal liquefaction over molten tin catalyst

Rates of formation of gases, oils, asphaltenes and preasphaltenes during non-solvent liquefaction of coal over molten tin catalyst have been measured. A probable reaction scheme and the rate constants for the pathways comprising the scheme have been presented. The results show that the catalyst greatly accelerates the conversion of preasphaltenes to asphaltenes. It also accelerates two other reactions, i.e., coal to preasphaltenes and coal to asphaltenes. By contrast, the catalyst does little to promote gasification and formation of oils.     

Poly(4-diphenylaminostyrene) with a well-defined polymer chain structure: Controllable optical and electrical properties

The effect of polymer chain structure on the optical and electrical properties are reported for poly(4-diphenylaminostyrene) (PDAS), which was prepared by the living anionic polymerization of 4-diphenylaminostyrene (DAS) with the benzyllithium (BzLi)/N,N,N′,N′-tetramethylethylenediamine (TMEDA) system. The optical properties of PDAS are strongly affected by the stereoregularity of the PDAS polymer chain; intramolecular excimer-forming fluorescence was observed from PDAS with a syndiotactic-rich configuration. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PDAS were approximately −5.4 and −2.0 eV, respectively, regardless of the polymer chain structure. The hole and electron drift mobilities for PDAS were in the order of 10⁻⁴ to 10⁻⁵ (cm²/V s) and 10⁻⁵ (cm²/V s), respectively, with negative slopes. The distance of each triphenylamino (TPA) group in the polymer chain was a major factor influencing the drift mobility of PDAS. The current-voltage (I-V) characteristics of PDAS were controllable according to the polymer chain structure of PDAS.     

Influence of electrolyte additives on safety and cycle life of rechargeable lithium cells

The influence of electrolyte additives on the safety and cycle life of 4V-class lithium cells is examined. The electrolyte solution employed was 1 M LiClO₄-propylene carbonate, the most widely used electrolyte in lithium battery research. The additives studied were ten organic aromatic compounds including biphenyl, cyclohexylbenzene and hydrogenated diphenyleneoxide. For safety, focus was given to the overcharging tolerance of the lithium cells. Biphenyl is well-known as an overcharge protection additive. The purpose of this work was to find additives with a higher oxidation potential and longer charge–discharge cycle life than biphenyl. The oxidation potentials and currents of the additives were measured to determine whether or not these compounds work as overcharge protection additives. Charge–discharge cycling efficiencies were examined for lithium metal anodes. The results showed that cyclohexylbenzene and hydrogenated diphenyleneoxide have a higher oxidation potential and a higher lithium cycling efficiency than biphenyl.     

Synthesis of porphyrin-end-functionalized poly(p-phenylene) as a leaf-green-colored soluble semiconducting polymer: Control of π–π interactions for visible-light absorption

The synthesis of tetraphenylporphyrin (H₂TPP)-end-functionalized poly(p-phenylene) (H₂TPP-PPP) as a leaf-green-colored soluble semiconducting polymer with a well-controlled and defined polymer chain structure was achieved for the first time. Chloromethyl-end-functionalized poly(1,3-cyclohexadiene) (CM-PCHD) was prepared by the living anionic polymerization of 1,3-cyclohexadiene and the post-polymerization reaction of poly(1,3-cyclohexadienyl)lithium and chloro(chloromethyl)dimethylsilane. H₂TPP-end-functionalized PCHD (H₂TPP-PCHD) was then prepared by the addition of 5-(4-hydroxyphenyl)-10,15,20-triphenylporphyrin to CM-PCHD. The dehydrogenation of H₂TPP-PCHD with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone was performed under ultrasonic irradiation, and H₂TPP-PPP was obtained as a target polymer in almost quantitative yield. The –Si(CH₃)₂–CH₂–O– bond in H₂TPP-PPP effectively inhibited the coordination of the H₂TPP end-group onto the PPP moiety, and the aggregation of H₂TPP-PPP with the accumulation of the H₂TPP end-group was formed. H₂TPP-PPP exhibited a leaf-green color and had a very broad absorption band overlapping the visible-light region, similar to chlorophyll a.