On a thermistor-pirani gauge of high sensitivity

Zusammenfassung Ein Hitzdrahtmanometer bildet, mit einem Thermistor in eine Wheatstone-Anordnung geschaltet, ein Thermistor-Pirani-Messgerät hoher Empfindlichkeit, das in einem weiten Gebiet eine lineare Druck-Strom-Abhängigkeit zeigt. Dabei wird von der verstärkenden Wirkung der negativen Widerstandcharakteristik eines Thermistors Gebrauch gemacht, um die von winzigen Druckänderungen herrührenden kleinen Widerstandvariationen zu verstärken.     

Argeloside A and B, two novel 14,15-secopregnane glycosides from Solenostemma argel

Argeloside A and B, two novel 14,15-secopregnane glycosides characterized by the presence of two hemiketal functions involved in two five-membered rings, were isolated from Solenostemma argel fruits. Their structures have been established by ESIMS and NMR experiments. In particular the relative configuration of the molecules has been defined by combining the available NMR data with quantum chemical calculations of the geometries and ¹³C chemical shifts.     

The effect of anti-viral drug treatment of human immunodeficiency virus type 1 (HIV-1) described by a fractional order model

In this paper, generalized Euler method (GEM) and homotopy analysis method (HAM) are performed to solve the problem of the population dynamics of the human immunodeficiency type 1 virus (HIV-1). We introduce fractional orders to the model of HIV-1 whose components are plasma densities of uninfected CD4⁺ T-cells, the infected such cells and the free virus. The effect of the drug treatment of HIV-1 will be discussed in this paper.