Tympanometry at a health center

We wanted to assess how much additional information could be gained from the results of tympanometry after first performing a clinical hearing examination at a mother and child clinic. 182 children aged from six months up to four years, had their hearing first examined clinically and afterwards by tympanometry. Pathological tympanograms were seen in 39% of the ears we examined, but most of them reverted to normal spontaneously at a later stage. There was little concordance between tympanometry and BOEL test in children aged six months and one year. Concordance between tympanometry and audiometry was fairly good in four-year old children. 27 children were referred to an ear, nose and throat specialist for evaluation, 11 of them as a result of tympanometry. Operative treatment was recommended for 17 of the children. In the anamnesis there was a connection between the parents perception of their child's hearing and the child having a cold and referral to an ear, nose and throat specialist. Tympanometry contributes to an early diagnosis of secretory otitis media, as well as being a means of helping parents understand the periodically poor middle ear function of their child.     

Auditory filters measured at neighboring center frequencies

Auditory filters were derived in 20 normal-hearing human listeners at center frequencies (CFs) of 913, 1095, 3651, and 4382 Hz using the roex (p,r) method. Comparisons were made between slopes of the filters' skirts at the neighboring CFs with filter output levels of 45 and 70 dB. The same comparisons were made with regard to filter equivalent rectangular bandwidth (ERB). In the 1000-Hz region, the low-frequency slopes (Pl) of filters centered at 913 and 1095 Hz were significantly correlated at both stimulus levels, while the high-frequency slopes (Pu) were similar only at the high test level. In the 4000-Hz region, for sinusoids of 3651 and 4382 Hz, the level effect was clearer as both Pu and Pl values diverged at the low level but were related at high levels. The ERBs centered at the same CFs displayed a similar level dependence. At the stimulus level most likely to be affected by an active feedback mechanism, auditory filters centered at nearly the same frequency displayed quite distinct frequency selectivity, and this trend was stronger in the 4000-Hz region than the 1000-Hz region. The findings suggest that a saturating, active cochlear mechanism may not be distributed evenly, or contribute to peripheral tuning with equal effectiveness throughout the length of the partition.     

Important problems in semiconductor technology and materialogy- at the center of attention

In addition to the problems encountered in the conventional metallurgy of ferrous and nonferrous metals, the Mining-Metallurgical Section of the Russian Academy of Natural Sciences (RAEN) devotes a considerable amount of its attention to problems in semiconductor technology and materialogy. To coordinate the work of scientists in this field, the section has established a special Committee on Semiconductor Materialogy and Technology. The new committee is headed by RANE President V. B. Ufimtsev and the director of the Institute of Chemical Problems of Microelectronic (IKhPM). Russian Academy of Natural Sciences and the Institute of Chemical Problems of Microelectronics. Translated from Metallurg, No, 12. p. 30, December, 1999.     

The learning research and development center at the University of Pittsburgh.

"In April of 1964 the Cooperative Research Branch of the United States Office of Education selected the 1st 2 research and development centers in a program designed to provide major concentrations of effort on various areas in education." 1 center, sociologically oriented, as at the University of Oregon and 1 psychologically oriented is at the University of Pittsburgh. The latter is described in this report. Major sections are: Background; Objectives; Activities (Research, Development, Dissemination); Organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Premature termination at a university counseling center.

Predicted that 3 sets of variables would discriminate between clients who returned for scheduled appointments following intake and clients who did not: (a) client perception of the intake counselor as expert, attractive, and trustworthy; (b) agreement of client and counselor on the presenting problem; and (c) client satisfaction with the intake interview. To test this prediction, 134 university students (mean age 22.9 yrs) completed the Client Satisfaction Questionnaire, a counselor rating form, and a client problem identification questionnaire after an intake interview. 30 of these Ss dropped out of counseling and 104 continued. It was found that client satisfaction and perceptions of trustworthiness and expertness were related to Ss' returning for scheduled appointments. No differences between continuers and dropouts were found with respect to client perceptions of counselor attractiveness or client–counselor agreement on problem identification. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Defects at center P underlie diabetes-associated mitochondrial dysfunction

Detailed respiration studies on isolated liver mitochondria from streptozotocin-induced diabetic Sprague-Dawley rats revealed a disease-associated decrease in the ADP/O ratio, a marker for mitochondrial ability to couple the consumption of oxygen to the phosphorylation of ADP. This decrease was observed following induction of respiration with glutamate/malate, succinate, or duroquinol, which enter the electron transport chain selectively at complexes I (NADH dehydrogenase), II (succinate dehydrogenase), or III (cytochrome bc1 complex), respectively. These data, coupled with studies using respiratory inhibitors (most importantly antimycin A and myxothiazol), localize at least a portion of this defect to a single site within the electron transport chain (center P in the Q-cycle portion of complex III). These results suggest that liver mitochondria from diabetic animals may generate increased levels of reactive oxygen species at the portion of the electron transport chain already established as the major site of mitochondrial free radical generation. The reduction in the ADP/O ratio occurred in mitochondria that do not have overt defects in the respiratory control ratio or in State 3 and State 4 respiration. The data in this paper suggest that defects in center P of the electron transport chain likely increase mitochondrial exposure to oxidants in the diabetic. This data may partially explain the evidence of altered exposure and/or response to reactive species in mitochondria from diabetics. This work thus provides further clues to the interaction between oxidative stress and diabetes-associated mitochondrial dysfunction.     

Married couples' experiences at a human reproduction center

The present study was intended to understand the feeling demonstrated by married couples seeking a Human Reproduction Center for infertility evaluation. Intending to understand the way Assisted Reproduction is experienced from the couple's perspective, a phenomenological approach was adopted and the directing question was: "How do you feel using the Assisted Reproduction as a treatment?"     

Electrostatic interactions at the donor side of the photosynthetic reaction center of Rhodopseudomonas viridis

The photosynthetic reaction center of Rhodopseudomonas viridis, a purple bacterium, contains a tetraheme cytochrome subunit. After its photoinduced oxidation, the primary donor, P, is reduced by the nearby heme (c559) of the tetraheme subunit in about 200 ns. This heme, in turn, is reduced by another heme (c556) of the subunit in about 2 micro(s). The midpoint potentials of P, c559, and c556 are known to be +500, +380, and +320 mV, respectively. The reduction kinetics of P+ are strongly biphasic in living cells, membrane fragments, and isolated reaction centers. We show here that this biphasicity reflects a small equilibrium constant (lower than 10) for the electron-transfer reaction between P and c559, which arises from a significant difference between the operating redox potentials of the P+/P and c559+/c559 couples and their equilibrium midpoint potentials. This difference is partly due to the effect of the permanent transmembrane potential, which arises from the cell metabolism, and to significant electrostatic interactions which develop between the electron carriers of the reaction center. Interestingly, the kinetic parameters of P+ reduction in decoupled cells or membrane fragments are identical to those reported for isolated reaction centers. We estimate an interaction of about 20 mV between c556 and c559 and about 90 mV between c559 and P. Consequently, the operating redox potential of the P+/P couple is 410 mV.     

马钢新区能源中心的建设与探讨

通过介绍马钢新区能源中心项目的建设背景、建设过程、监控范围、技术特点和运行概况,阐述了能源中心在钢铁企业中实现节能降耗和管理节能上所发挥的作用,对钢铁冶金企业能源中心建设的共性问题进行了探讨.