Measurement of Blood Hematocrit Inside the Magnetically Suspended Centrifugal Pump Using an Optical Technique: Application to Assessment of Pump Flow

To measure blood hematocrit inside the magnetically suspended centrifugal pump, we have performed both forward and backward light scattering measurements using a specially designed optical cell. In the forward scattering measurement, an optical fiber was used to guide the near infrared light at 780 nm into a 250 microns gap region, and the light that forward scattered toward a detector fiber was measured using a phototransistor. The light intensity decreased exponentially with an increase in the hematocrit to around 20%. The forward scattering method suffered from sensitivity at the hematocrit levels around 25-45% due to the diffusion effect. By making the optical path length larger than several millimeters, the sensitivity of the forward scattering method in terms of hematocrit change can be improved. In the back scattering method, however, better sensitivity in terms of hematocrit change from 0-50% was obtained. By making the optical fiber separation distance less than 1 mm, the system will measure the first order back scattering from the shallow layer while, by making the fiber separation distance larger than several millimeters, the system will primarily measure the diffuse reflectance from the deeper layer. Both approaches will yield sensitive optical intensity change in terms of the physiological hematocrit range.     

Mechanical Properties of Aramid/Carbon Hybrid Fiber-Reinforced Concrete

In this study, aramid fiber (Kevlar^® 29 fiber) and carbon fiber were added into concrete in a hybrid manner to enhance the static and impact mechanical properties. The coupling agent presence on the surface of carbon fibers was spotted in Scanning Electron Microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) graphs. The carbon fiber with a coupling agent affected the mechanical strength of the reinforced concrete. At 1% fiber/cement weight percentage, the hybrid fiber-reinforced concrete (HFRC) prepared using Kevlar fiber and carbon fiber of 12 and 24 mm in length under different mix proportions was investigated to determine the maximum mechanical strengths. From the test results, the mechanical strength of the HFRC attained better performance than that of the concrete with only Kevlar or carbon fibers. Foremost, the mix proportion of Kevlar/carbon fiber (50–50%) significantly improved the compressive, flexural, and splitting tensile strengths. Under different impact energies, the impact resistance of the HFRC specimen was much higher than that of the benchmark specimen, and the damage of the HFRC specimens was examined with an optical microscope to identify slippage or rupture failure of the fiber in concrete.     

光纤间接免疫荧光法检测肺炎支原体抗体

目的和方法:首次采用自行设计、研制的光纤荧光光度计对肺炎支原体抗体进行了检测,并将该法与临床上现行ELISA法及荧光显微镜法进行比较测定.结果:此法标准曲线的相关系数r=0.9930,测定的相对荧光强度(△F)大于2.0为阳性,小于2.0为阴性,且稳定性好.检测35人次临床血清标本,18例阳性标本中,本法有19例为阳性,与ELISA法及荧光显微镜法符合率(特异性)为94.4%;17例阴性标本中,本法有16例为阴性,符合率为94%结论:表明本光纤法具有特异性好、敏感性高,还具有可定量,操作简便快速,所需样本量微,所用仪器新颖、价廉、易普及等优点.     

接骨板固定及取出后局部骨量、骨结构和骨强度变化的相关研究

目的：了解坚硬接骨板固定及取出后局部骨量,骨结构和骨强度的变化及其相关性。方法：选用成年新西兰兔７２只,８只正常对照。６４只在左胫骨作不锈钢固定,其中４０只于术后２月取钢板,然后在取钢板当时及取钢板后１,２,３和４个胃８只动物处死。另有２４只动物不取钢板,至内固定后３,４和６月份分期处死。取材作光镜,定量组织分别有８只动物处死。     

Muscle fiber conduction velocity in situ (MFCV) in denervation, reinnervation and disuse atrophy

OBJECTIVES: Muscle fiber conduction velocity (MFCV) was performed in disuse atrophy, in denervated muscle and during reinnervation as a possible index of muscle atrophy, and to clarify the evolution of the fiber size. MATERIAL AND METHODS: MFCV was performed in 12 patients with complete denervation of biceps brachii muscle and during various stages of reinnervation. Twenty-one patients with disuse quadriceps atrophy were also tested. Invasive MFCV was performed according to the method reported elsewhere (2). RESULTS: MFCV decreased significantly in denervated muscles. Reduction of MFCV was found during the first weeks and was progressive. Peak frequency in histograms decreased and the normal Gaussian distribution was lost. MFCV increased progressively after reinnervation with coexistence of slow and significant increase of faster MFCV. MFCV decreased significantly also during the first weeks after immobilization and improved by rehabilitation therapy. CONCLUSION: MFCV is a reliable method to test the muscle fiber size after denervation and immobilization, and its evolution by reinnervation and therapy.     

Mu opioids enhance mossy fiber synaptic transmission indirectly by reducing GABAB receptor activation

The cellular mechanisms underlying mu opioid facilitation of mossy fiber (MF) long-term potentiation (LTP) and synaptic transmission were investigated in the rat hippocampal slice. Naloxone (10 μM) significantly inhibited the induction of mossy fiber LTP, an effect attributed by Derrick and Martinez [B.E. Derrick, J.L.J. Martinez, Opioid receptor activation is one factor underlying the frequency dependence of mossy fiber LTP induction, J. Neurosci. 14 (1994) 4359–4367] to antagonism of endogenous opioid peptide action. We found that the inhibitory effects of naloxone were not blocked by bicuculline, suggesting that endogenous opioids did not enhance mossy fiber LTP by depressing GABA_A inhibition. [ -Ala2, NMePhe4, Glyol5] enkephalin, DAMGO (300 nM), a mu opioid agonist, mimicked the action of endogenous opioids, enhancing both mossy fiber LTP induction and paired-pulse facilitation. DAMGO potentiation of the paired-pulse facilitation of mossy fiber response was also insensitive to bicuculline but was blocked by the mu selective antagonist CTOP. Further analysis of the cellular mechanism showed that the depletion of internal Ca²⁺ stores by thapsigargin (1 μM), or inhibition of protein kinases by application of staurosporine (1 μM) did not block the DAMGO facilitation of mossy fiber–CA3 synaptic transmission. However, application of phaclofen (100 μM GABA_B receptor antagonist or SCH 50911, a more potent GABA_B antagonist significantly inhibited the DAMGO effect (49±15%; 51±19% inhibition, P<0.05). The data indicate that the DAMGO effect on the mossy fiber pathway is partially mediated by a reduction in GABA activation of GABA_B receptors. These findings further suggest that endogenous opioid peptides activate mu opioid receptors to facilitate mossy fiber LTP and synaptic transmission in rat hippocampus partially by GABA_B receptor-mediated disinhibitory mechanism.     

Serial SFEMG studies of orbicularis oculi muscle after the first administration of botulinum toxin

Serial single fiber electromyography (SFEMG) examinations of orbicularis oculi muscle in patients with blepharospasm or hemifacial spasm treated with botulinum toxin injections were performed. The aim of the study was to evaluate the impairment of neuromuscular transmission, to follow reinnervation after botulinum toxin administration and to find out whether there was a relationship between SFEMG parameters and clinical symptoms. Examinations were performed before injection, during early and late remission of symptoms, and after recurrence of the involuntary movement. Severe impairment of neuromuscular transmission, as revealed by increased jitter and increased presence of abnormal potential pairs and pairs with blocking, was found in early remission, but fiber density remained unchanged when compared with pretreatment values. In late remission, increased fiber density was registered for the first time. The recurrence of involuntary movements was related to the further increase of fiber density and tendency to normalization of jitter parameters. The study therefore suggests that formation of new neuromuscular junctions and their functional maturation is responsible for muscle recovery after botulinum toxin administration.     

Influence of Polypropylene and Steel Fibers on the Performance and Crack Repair of Self-Compacting Concrete

The research reported in this paper aims to evaluate the epoxy injection technique used to strengthen fiber-reinforced self-compacting concrete (FRSCC) with high strength. This method is carried out on ruptured concrete specimens to assess the efficiency of the epoxy resin adhesive injection retrofitting technique for strength and stiffness. Five FRSCC mixes were designed and placed using different types (steel and polypropylene) and contents (0%, 0.25%, and 0.45% by volume) of fibers. The fresh and mechanical properties in addition to the microstructure of produced mixes were evaluated to assess the impact of fibers on the behavior of FRSCC. Results showed that the workability of FRSCC is reduced by increasing steel or polypropylene fiber content; however, the rheological characteristics of placed mixes satisfied the European Guidelines for Self-Compacting Concrete recommendation for fresh concrete. Also, splitting tensile, flexural, and shear strengths were enhanced by increasing fiber content. The simultaneous application of epoxy injection in FRSCC for repairing damaged concrete beams was shown to be highly effective.     

大鼠海马内胆碱能纤维损伤后的侧枝抽芽

目的观察穹窿海马伞损伤鼠海马胆碱能纤维损伤后的再生状况。方法切断SD成年大鼠穹窿海马伞,用染AChE纤维的组织化学方法结合网格测试,分析术后1、2、3、4周海马Cal区和齿状回的分子层胆碱能纤维的侧支抽芽。结果损伤1周时Cal区和齿状回的分子层胆碱能纤维明显减少,分别减少到67．50％和66．9l％;从第2周开始纤维数量逐渐恢复,至第4周Cal区分子层纤维恢复到正常的82．42％,而齿状回分子层纤维恢复到97．82％。结论成年哺乳类海马内胆碱能纤维损伤后有很强的侧支抽芽能力。