Acid phospholipase A activities in rat hepatocytes

AbstractCultured rat hepatocytes exhibit acid phospholipase A activity. On the basis of product formation from stereospecifically radiolabeled phosphatidylethanolamine substrates, phospholipases A1 and A2 have been identified with optimal activities at pH 4.5. According to subcellular fractionation studies, the acid phospholipases in hepatocytes appear to be located in the lysosomal compartment. Application of specific inhibitors of the biosynthesis, glycosylation, and translocation of lysosomal enzymes in hepatocyte cultures suggests a half-life of approx. 1 day for the acid lysosomal phospholipase A1. About the same value for the half-life was obtained for the lysosomal marker enzymes, acid phosphatase and β-N-acetyl-D-hexosaminidase

Diacylglycerol hydrolysis in rat liver lysosomes

AbstractThe matrix of rat liver lysosomes exhibits high hydrolytic activity towards 1,2-diacylglycerol with an optimum at pH 4.0. The lipolytic reaction follows Michaelis-Menten kinetics (apparent Vmax 470 nmol hydrolysedmin per mg protein; apparent Km71 μM 1,2-dioleoylglycerol). Formation of 1- and 2-monooleoylglycerols indicates an initial attack at both the primary and secondary ester bonds. The lysosomal matrix also catalyses (re)acylation reactions, i.e. the formation of 1,2-diacylglycerol from 2-monoacylglycerol and free fatty acid. However, (re)acylation proceeds at a far lower rate than deacylation of diacylglycerol. Lysosomal diacylglycerol hydrolysis is sensitive towards non-ionic detergents, cationic amphiphilic drugs and the lipase inhibitor RHC 80267

On the influence of material properties in sheet bending processes

In order to achieve the high performance and precision requirements of modern sheet bending processes, an appropriate implementation of material properties is essential. Experiments have shown that even variations within a lot of a specific material play an important role. For this sake, detailed knowledge of the influence of the specific properties like flow curve, rolling direction, strain rate, anisotropy etc. is required. In a first step, tension tests have been performed for some materials which are frequently used in industrial applications. In order to simulate the sheet bending process, advanced simulation models have been implemented. Detailed parameter studies have been performed, and the essential parameters and their influence on the bending process have been found out. The results have been compared to measurement results of the bending process

Nitrogen laser beam interaction with copper surface

The ultraviolet and visible spectra of plasmas produced by N_2-laser radiation focused onto a copper target in air and in vacuum have been recorded photographically. The nitrogen laser beam (α = 337 nm) had a maximum energy density of 1.1 J/cm^2, the pulse duration was 6 ns, and the repetition rate 0.2 Hz. The measured electron temperature was 15000 K (±30%) in air and 13000 K (±50%) in vacuum and the electron densities were 6.5×10^17 cm^-3 (±60%) and 3.0×10^17 cm^-3 (±60%), respectively. The irradiated surface in air and in vacuum was studied employing a metallographic microscope. In vacuum, the droplets were created and expulsed at the crater edges. Their formation is explained by the hydrodynamical model. They were formed in a time interval which is about two times shorter than the duration of the laser pulse. In air, droplets were also formed. The weight loss from the Cu-crater in vacuum was about 0.3×10^-4 µmole/pulse, in air it was about three times less

LEAN PANEL BENDER – Einige mechanische Aspekte der Modellierung in Echtzeit für Produktion in Losgröße 1

Nachfolgend werden einige wissenschaftliche Aspekte der Echtzeit-Materialerkennungsstrategie MAC diskutiert, die in der neuen Maschinenfamilie LEAN PANEL BENDER der Firma Salvagnini Maschinenbau realisiert ist und die eine hochpräzise und hocheffiziente Herstellung von komplex geformten Blechprodukten sowohl bei Losgröße 1 als auch in der Serie erlaubt.(VLID)342339

One-dimensional arrangements of metal atoms in transition metal carbonyl complexes of mixed main group metal alkoxides

Mixed metal alkoxides containing main group elements with ns2 electron configurations of the general formula M(OtBu)3M\u27 (M = In, Tl; M\u27 = Ge, Sn, Pb), M\u27(OtBu)3M(OtBu)3M\u27 (M = divalent metal atom, M\u27 = Ge, Sn) and (OtBu)M\u27(OtBu)2M(OtBu)2M\u27(OtBu) (M = Co, Ni; M\u27 = Ge, Sn) can be reacted with simple metal carbonyls. The products obtained are composed of a one-dimensional array of metal atoms held together by direct metal-metal bonds or by bridging alkoxide groups. The following compounds have been isolated and characterized by IR and NMR spectroscopy and X-ray diffraction (M\u27 = Ge, Sn, Pb; M = In, Tl; MT = transition metal): M\u27(OtBu)3M-MT(CO)n, (CO)nMT-M(OtBu)3M\u27-MT(CO)n, M\u27(OtBu)3M-MT(CO)nM(OtBu)3M\u27, (CO)nMT-M\u27(OtBu)3M(OtBu)3M\u27-MT(CO)n, (CO)nMT-M\u27[OtBu](OtBu)2M(OtBu)2M(OtBu)2[OtBu]M\u27-MT(CO)n and (CO)nMT-M\u27(OtBu)3M-MT(CO)nM(OtBu)3M\u27-MT(CO)n. In addition, an oligomeric species of the general formula [Sn(OtBu)3In-Mo(CO)4]n-Sn(OtBu)3In-Mo(CO)5 with n ~ 9, 10 has been isolated

Study of laser-produced plasmas from boron, carbon and boron-carbide targets

Spectroscopic investigations were made on plasma clouds created by 20 ns, 3 J ruby laser pulses impinging perpendicularly onto targets of boron carbide, carbon and boron. The irradiance on the targets was about 132 GW cm^-2. Time-resolved spectra of plasmas in the region of wavelength from 16 to 32 nm were observed at a distance of 1 mm from the targets. The maximum electron temperatures were about 60 eV in the case of carbon and boron targets, and about 45 eV in the case of boron-carbide target. Laser evaporation from carbon occurred directly from the solid state (sublimation), and in the case of a boron and boron-carbide melting was observed as an intermediate state

Silicon surface irradiated by nitrogen laser radiation

Monocrystalline silicon target was irradiated with a nitrogen laser beam (alfa = 337 nm, maximum energy density 1.1 J/cm^2, pulse duration 6 ns and repetition rate 0.2 Hz). The plasma formed at the silicon surface was observed spetroscopically in air (n_e = 3×10^18 cm^-3, T_e = 18 500 K) and in vacuum (n_e = 6.5×10^17 cm^-3, T_e = 16 000 K). The irradiated surface in vacuum was studied by a metallographic microscope. Droplets were created at crater edges. Their formation is explained by the hydrodynamical sputtering model

Površina silicija ozračena dušikovim laserskim zračenjem

Monocrystalline silicon target was irradiated with a nitrogen laser beam (λ = 337 nm, maximum energy density 1.1 J/cm2, pulse duration 6 ns and repetition rate 0.2 Hz). The plasma formed at the silicon surface was observed spetroscopically in air (ne = 3×1018 cm-3, Te = 18 500 K) and in vacuum (ne = 6.5×1017 cm-3, Te = 16 000 K). The irradiated surface in vacuum was studied by a metallographic microscope. Droplets were created at crater edges. Their formation is explained by the hydrodynamical sputtering model.Monokristalni silicij se ozračivao snopom iz dušik ovog lasera (λ = 337 nm, maksimalna snaga 1.1 J/cm2 , trajanje pulsa 6 ns i frekvencija 0.2 Hz). Plazma nastala na površini silicija se promatrala spektroskopski u zraku (ne = 3 = 1018 cm 3 , Te 18500 K) i u vakuumu (ne = 6 ¬ 5 = 1017 cm 3 , Te = 16000 K). Površina ozračena u vakuumu se proučavala pomoću metalografskog mikroskopa. Opazile su se kapljice oko ruba udubine na siliciju. Nastajanje kapljica se tumači hidrodinamičkim modelom