83 research outputs found
O-Methylating enzymes of dopamine and dopamine derived tetrahydroisoquinoline, salsolinol
Physiology and pathophysiology of the vasopressin-regulated renal water reabsorption
To prevent dehydration, terrestrial animals and humans have developed a sensitive and versatile system to maintain their water homeostasis. In states of hypernatremia or hypovolemia, the antidiuretic hormone vasopressin (AVP) is released from the pituitary and binds its type-2 receptor in renal principal cells. This triggers an intracellular cAMP signaling cascade, which phosphorylates aquaporin-2 (AQP2) and targets the channel to the apical plasma membrane. Driven by an osmotic gradient, pro-urinary water then passes the membrane through AQP2 and leaves the cell on the basolateral side via AQP3 and AQP4 water channels. When water homeostasis is restored, AVP levels decline, and AQP2 is internalized from the plasma membrane, leaving the plasma membrane watertight again. The action of AVP is counterbalanced by several hormones like prostaglandin E2, bradykinin, dopamine, endothelin-1, acetylcholine, epidermal growth factor, and purines. Moreover, AQP2 is strongly involved in the pathophysiology of disorders characterized by renal concentrating defects, as well as conditions associated with severe water retention. This review focuses on our recent increase in understanding of the molecular mechanisms underlying AVP-regulated renal water transport in both health and disease
Endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of intrathoracic lymph node metastases from extrathoracic malignancies
Transgenic expression of human APOL1 risk variants in podocytes induces kidney disease in mice
Transgenic expression of human APOL1 risk variants in podocytes induces kidney disease in mice
Universal features in the electrical conductivity of icosahedral Al-transition-metal quasicrystals
Characteristics And Fabrication Of A Narrow Gap Transducer
The fundamental characteristics of a narrow gap transducer have been investigated theoretically and experimentally. A SAW transducer with narrow gaps between electrodes, a Metallization ratio (denoted by a/p) of greater than 903!, has potential application to high frequency devices. Comparable to the split finger electrode transducer, the electrode reflections within the narrow gap transducer are negligibly small. A narrow gap transducer doubles the center frequency for a given line width as compared with a conventional transducer(a/p=50X). It relaxes the restriction on fabrication and lowers the resistance of the electrodes. The strong harmonics of the transducer can be also used for possible higher frequency application. The test devices are fabricated by a self aligned liftoff process without using anodization. The experiment shows no internal reflections and a strong series of harmonics. This paper presents theoretical and experimental results for the narrow gap devices under development
Initial Stage of Localized Corrosion in Artificial Pits Formed with Photon Rupture on 55mass%Al–Zn Coated Steels
Biosorption of lead from acid solution using chitosan as a supporting material for spore forming-fungal biomass encapsulation
Asexual spores of the filamentous fungus Rhizopus arrhizus were used
as the resting biomass as they tolerate chitosan gelling for mycelia
growing in chitosan beads. Biosorption of lead using the dead detergent
pre-treated chitosan-immobilised and grown fungal beads was performed
with initial lead (II) nitrate concentrations ranging from 9.02 to
281.65 mg/L. The adsorption data were best correlated with equilibrium
adsorption isotherms in the order Redlich–Peterson, Langmuir,
Freundlich and Fritz–Schlünder by non-linear regression. The
biosorption kinetic model of pseudo second-order (R2 > 0.99) fitted
better than pseudo first-order and modified pseudo first-order models.
Among the four pseudo second-order kinetic models, the Blanchard model
was the best fit for the experimental biosorption data. The
rate-limiting step of biosorption of lead was shown to be intraparticle
diffusion controlled according to Weber and Morris model fitting. The
beads could be regenerated using 1 M nitric acid solution. This
illustrated the good performance of the beads for regenerated
sorption/desorption at least five cycles
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