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71.
72.
In many terrestrial tetrapodes, a pair of vomeronasal organs (VNOs), which are chemosensory apparatuses, are situated at the base of the nasal septum in the anterior nasal cavity. The purposes of this review are to summarize comparative neuroanatomy and to introduce recent progress in neurobiological studies of the VNO. Five types of VNOs can be identifiable in terms of anatomical organization; snakes possess the most complex one. Sensory cells in the VNO, vomeronasal receptor neurons (VRNs), are located in its neuroepithelium, vomeronassal sensory epithelium. The VRNs retain the characteristic of epithelial cells in that they are born continuously from progenitor cells. They contain two prominent subcellular structures: microvilli and extraordinarily large amounts of smooth endoplasmic reticulum and a few unique glycoconjugates. The VRNs express two types of G-protein -subunits: Gi(alpha2) and Go(alpha) and each of them is coupled with putative pheromone receptors, V1Rs and V2Rs, respectively. Recent physiological and biochemical studies have demonstrated that pheromones depolarize the V1R-Gi(alpha2) and V2R-Go(alpha) VRNs via IP(3)-mediated mechanisms. The VRNs do not show adaptation and are ultrasensitive to putative pheromones. Other than being a chemosensory organ, the VNO and its primordium might play important roles for brain development; hypothalamic neurons that produce gonadotropin-releasing hormone are born in the VNO primordium and a few other neuron-like cells may be born in the VNO primordium and VNO. In human fetuses, anatomical findings strongly suggest that their VNOs contain a neuroepithelium. By contrast, it is unlikely that adult human VNO serves as a chemosensory organ.  相似文献   
73.
Nonresonant microwave absorption (NMA) measurements were carried out at liquid-nitrogen temperature on a high quality Bi2212 single crystal, as a function of microwave power in three mutual orientations of crystal ab plane, dc field (Hdc), and microwave magnetic field (Hw). NMA line shapes in Bi2212 crystal are complicated with a narrow peak (P1 peak) located near zero field, followed by a much broader second peak (P2 peak) in the particular orientations. More excitingly, we show that the P2 peak qualitatively evolves as a function of microwave power in the orientation of Hdc ab plane, plane, and Hdc Hw. In this configuration, as the microwave power is progressively increased, the broad P2 peak first gets smeared off and then a multiple peak structure appears, which develops into another narrower second peak (Ps-peak) at high enough microwave powers. In the orientation of plane, Hw ab plane, and Hdc Hw, we report for the first time the appearance and disappearance of a new second peak (P2-like peak) as a function of microwave power.  相似文献   
74.
The balance between oxidative phosphorylation and glycolysis is important for cancer cell growth and survival, and changes in energy metabolism are an emerging therapeutic target. Adenylate kinase (AK) regulates adenine nucleotide metabolism, maintaining intracellular nucleotide metabolic homeostasis. In this study, we focused on AK3, the isozyme localized in the mitochondrial matrix that reversibly mediates the following reaction: Mg2+ GTP + AMP ⇌ Mg2+ GDP + ADP. Additionally, we analyzed AK3-knockout (KO) HeLa cells, which showed reduced proliferation and were detected at an increased number in the G1 phase. A metabolomic analysis showed decreased ATP; increased glycolytic metabolites such as glucose 6 phosphate (G6P), fructose 6 phosphate (F6P), and phosphoenolpyruvate (PEP); and decreased levels of tricarboxylic acid (TCA) cycle metabolites in AK3KO cells. An intracellular ATP evaluation of AK3KO HeLa cells transfected with ATeam plasmid, an ATP sensor, showed decreased whole cell levels. Levels of mitochondrial DNA (mtDNA), a complementary response to mitochondrial failure, were increased in AK3KO HeLa cells. Oxidative stress levels increased with changes in gene expression, evidenced as an increase in related enzymes such as superoxide dismutase 2 (SOD2) and SOD3. Phosphoenolpyruvate carboxykinase 2 (PCK2) expression and PEP levels increased, whereas PCK2 inhibition affected AK3KO HeLa cells more than wild-type (WT) cells. Therefore, we concluded that increased PCK2 expression may be complementary to increased GDP, which was found to be deficient through AK3KO. This study demonstrated the importance of AK3 in mitochondrial matrix energy metabolism.  相似文献   
75.
76.
A totally implantable centrifugal artificial heart has been developed. The plastic prototype, Gyro PI 601, passed 2 day hemodynamic tests as a functional total artificial heart, 2 week screening tests for antithrombogenicity, and 1 month system feasibility. Based on these results, a metallic prototype, Gyro PI 702, was subjected to in vivo left ventricular assist device (LVAD) studies. The pump system employed the Gyro PI 702, which has the same inner dimensions and the same characteristics as the Gyro PI 601, including an eccentric inlet port, a double pivot bearing system, and a magnet coupling system. The PI 702 is driven with the Vienna DC brushless motor actuator. For the in vivo LVAD study, the pump actuator package was implanted in the preperitoneal space in two calves, from the left ventricular apex to the descending aorta. Case 1 achieved greater than 9 month survival without any complications, at an average flow rate of 6.6 L/min with 10.2 W input power. Case 2 was killed early due to the excessive growth of the calf, which caused functional obstruction of the inlet port. There was no blood clot inside the pump. During these periods, neither case exhibited any physiologic abnormalities. The PI 702 pump gives excellent results as a long-term implantable LVAD.  相似文献   
77.
A 64-year-old woman presented with cardiomegaly, Sweet's syndrome, and refractory anemia (RA), and died of sudden cardiac arrest. The autopsy revealed a perivascular and myocardial infiltration by neutrophils, which could be responsible for the cardiomegaly and probably had caused disturbances in the conduction system leading to sudden cardiac arrest. Myocardial infiltration by functionally defective neutrophils can develop in a patient with myelodysplastic syndrome (MDS) without peripheral neutrophilia or leukemic blood picture and needs a special diagnostic and therapeutic consideration.  相似文献   
78.
Complex dynamic properties of a bolus in the mouth are specified by touch. Cooperation between touch and taste may help to specify the character of the bolus. The role of touch in specifying the presence of the oral bolus, in contrast to it's characteristics, remains a theoretical and experimental challenge.  相似文献   
79.
This paper describes, for the first time to the authors' knowledge, the phenomenon of nonuniform azimuth image shift of a rigid body observed in the Radarsat synthetic aperture radar (SAR) images of cruising ships. The effect is caused by the different slant-range velocities of coherent scatterers across the hull associated with the ship motions. The slant-range velocity is estimated from the SAR image of an identified ship, and it is compared with that computed from a numerical model using the ship's specification and meteorological data. The result indicates that the dominant contribution to the nonuniform image shift is the pitching motion of the ship. Further comparison is made with the wave orbital velocity, and the results are shown to be in good agreement. Comparisons are also made between the SAR-derived slant-range velocities of two unknown ships and wave orbital velocities, and reasonable agreement is obtained. One of the ships' images exhibits not only nonuniform shift but also image skew. The latter skewing effect may be caused by rolling of the ship.  相似文献   
80.
One of the main concerns of strips producers is to measure strip thickness accurately as it is produced. Correct modelling of the sensitivity of output variables to input variables in a rolling mill model is one of the keys to obtaining more accurate data. An adaptive control system that uses an artificial neural network (ANN) creates a model of the process directly from measurement data. Using the model, the control system can predict how the process will react to control actions. The creation of the model and the computation of the control strategy are carried out automatically by the control system. The proportional–integral–derivative controller is used in this method to increase accuracy of final estimated variables and to increase accuracy of control of the system. To determine the correct tuning for thickness control, three control parameters are considered: the roll gap, and front and back tensions. A predictive model is used, based on the sensitivity equations of the process, where the sensitivity factors are computed by differentiating a previously trained neural network. Results of a case study in a real plant show that this online-offline model is effective in reducing thickness variations in produced strips.  相似文献   
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