In the present study, well-defined PVAc-b-PSt block copolymers were successfully synthesized for ... more In the present study, well-defined PVAc-b-PSt block copolymers were successfully synthesized for the first time by a combination of CMRP and RAFT polymerization. PVAc and PVAc-b-PSt macroinitiators were first synthesized via CMRP and then the cobalt complex attached to their ω chain ends was converted into a dithioester group for the RAFT polymerization of St. Experimental Materials. VAc (Aldrich, >99%) and St (Tokyo Kasei, 98%) were passed through a column filled with neutral alumina, dried over CaH 2, distilled under reduced pressure, and then degassed with several freezethawing cycles. N,N -dimethylformamide (DMF, Duksan, 99.5%) was dried over CaH 2, distilled under reduced pressure, and then degassed with several freeze-pump-thaw cycles. 2,2’-Azobis(isobutyronitrile) (AIBN, Tokyo Kasei, 98%) was recrystallized from methanol. 2,2’-Azobis(4-methoxy-2,4dimethylvaleronitrile) (V-70, Wako, 96%), cobalt(II) acetylacetonate [Co(acac) 2, Aldrich, 97%], dimethyl sulfoxide (DMSO, Aldrich, ≥99.7%), tetrahydrofuran (THF, Duksan, 99.5%), N,N -dimethylformamide (DMF, Aldrich, ≥99.8%), potassium hydroxide (KOH, Duksan, 85%), and methanol (Duksan, 99.5%) were used as received. CMRP of VAc. The CMRP of VAc was performed in the presence of Co(acac) 2 with V-70 at 30 o C. The CMRP of VAc at a ratio of [VAc]0/[V
Clinical and experimental otorhinolaryngology, 2009
To compare tinnitus patients who have normal hearing between 250 Hz and 8 kHz with normal control... more To compare tinnitus patients who have normal hearing between 250 Hz and 8 kHz with normal controls with regard to the ability of each group to hear extended high-frequency pure tone thresholds. We enrolled 18 tinnitus patients, each of whom had a threshold of HL <25 dB and threshold differences of <10 dB between ears at frequencies of 250 and 500 Hz and 1, 2, 4, and 8 kHz. We also enrolled age- and gender-matched normal volunteers (10 ears), for each patient. Extended high frequency pure tone audiometry was performed, and the mean hearing thresholds at 10, 12, 14, and 16 kHz of each tinnitus ear were compared with those of the 10 age- and sex-matched normal ears. Of the 18 patients with tinnitus, 12 had significantly increased hearing thresholds at more than one of the four high frequencies, compared with the normal group. When we assessed results according to frequency, we found that 8 patients had decreased hearing ability at 10 kHz, 10 at 12 kHz, 8 at 14 kHz, and 4 at 16 kH...
In the present study, well-defined PVAc-b-PSt block copolymers were successfully synthesized for ... more In the present study, well-defined PVAc-b-PSt block copolymers were successfully synthesized for the first time by a combination of CMRP and RAFT polymerization. PVAc and PVAc-b-PSt macroinitiators were first synthesized via CMRP and then the cobalt complex attached to their ω chain ends was converted into a dithioester group for the RAFT polymerization of St. Experimental Materials. VAc (Aldrich, >99%) and St (Tokyo Kasei, 98%) were passed through a column filled with neutral alumina, dried over CaH 2, distilled under reduced pressure, and then degassed with several freezethawing cycles. N,N -dimethylformamide (DMF, Duksan, 99.5%) was dried over CaH 2, distilled under reduced pressure, and then degassed with several freeze-pump-thaw cycles. 2,2’-Azobis(isobutyronitrile) (AIBN, Tokyo Kasei, 98%) was recrystallized from methanol. 2,2’-Azobis(4-methoxy-2,4dimethylvaleronitrile) (V-70, Wako, 96%), cobalt(II) acetylacetonate [Co(acac) 2, Aldrich, 97%], dimethyl sulfoxide (DMSO, Aldrich, ≥99.7%), tetrahydrofuran (THF, Duksan, 99.5%), N,N -dimethylformamide (DMF, Aldrich, ≥99.8%), potassium hydroxide (KOH, Duksan, 85%), and methanol (Duksan, 99.5%) were used as received. CMRP of VAc. The CMRP of VAc was performed in the presence of Co(acac) 2 with V-70 at 30 o C. The CMRP of VAc at a ratio of [VAc]0/[V
Clinical and experimental otorhinolaryngology, 2009
To compare tinnitus patients who have normal hearing between 250 Hz and 8 kHz with normal control... more To compare tinnitus patients who have normal hearing between 250 Hz and 8 kHz with normal controls with regard to the ability of each group to hear extended high-frequency pure tone thresholds. We enrolled 18 tinnitus patients, each of whom had a threshold of HL <25 dB and threshold differences of <10 dB between ears at frequencies of 250 and 500 Hz and 1, 2, 4, and 8 kHz. We also enrolled age- and gender-matched normal volunteers (10 ears), for each patient. Extended high frequency pure tone audiometry was performed, and the mean hearing thresholds at 10, 12, 14, and 16 kHz of each tinnitus ear were compared with those of the 10 age- and sex-matched normal ears. Of the 18 patients with tinnitus, 12 had significantly increased hearing thresholds at more than one of the four high frequencies, compared with the normal group. When we assessed results according to frequency, we found that 8 patients had decreased hearing ability at 10 kHz, 10 at 12 kHz, 8 at 14 kHz, and 4 at 16 kH...
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