Search Results - (Author, Cooperation:L. Olsson)

2013-11-10

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Anniversaries and Special Events ; *Biological Evolution ; Humans ; Religion and Science ; Russia ; *Selection, Genetic ; Translations

2012-03-17

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

*Conservation of Natural Resources ; *Environment ; *Government ; *International Cooperation ; Policy ; Technology ; *United Nations

2018-11-02

The American Association for Cancer Research (AACR)

1078-0432

1557-3265

Medicine

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

We present a three-dimensional micropositioner using the inertial slider principle which is used to position an optical fiber in an atomic force microscope. It uses only two moving parts as the sideways and vertical motions are realized by either moving a cylinder along its axis or rotating it around its axis and translating the rotation into an approximately vertical motion. The device operates reliably in a baked ultrahigh vacuum system, allows positioning with sub-μm accuracy, and has a forward range of 11.3 mm, a sideways range of 5 mm, and a vertical range of approximately 5 mm. The measured speeds without extra load fall in the range between 1.6 and 3.3 mm/min, in good agreement with the amplitude and curve shape of the applied drive signal. The minimal step size allowing consistent motion is below 25 nm. © 1996 American Institute of Physics.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: The membrane lipid composition of human frontal and temporal cortices and white matter has been studied in 118 subjects, age 20–100 years. The brain specimens were selected from subjects who lived a normal social life and died suddenly and unexpectedly with no history of neurologic or psychiatric disease. Macroscopic and microscopic examinations ruled out any signs of organic brain disorder. The sudden death eliminated all risk of changes over a long agonal stage. The data for total solids and major lipids are summarized in graphic form. Total solids, phospholipids, and cholesterol diminished linearly from 20 years of age in frontal and temporal cortices, whereas total solids phospholipids, cholesterol, cerebroside, and sulfatide showed a curvilinear diminution in frontal and temporal white matter. Gangliosides differed from the other lipids, showing an almost constant concentration between 20 and 70 years of age with a slight peak around 50 years of age. The ganglioside pattern showed continuous change with aging, with decreasing proportions of GM1 and GD1a and increasing proportions of GD1b, GM3, and GD3. Equations are given that can be used to calculate the lipid composition of normal human frontal and temporal cortices and white matter at any age between 20 and 100 years of age. These data can be used where data by direct analysis are not available for comparison with values for various pathological states.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

We present a combined scanning force/scanning tunneling microscope (SFM/STM) operating in ultrahigh vacuum using a fiber-optic laser interferometer to detect the lever deflection. As force microscope it operates in ac and dc mode with commercial (Si, Si3N4) or individually made (W) cantilevers. Samples and cantilevers can be inserted without breaking the vacuum using a load-lock system. The force sensor includes a novel three-dimensional micropositioner based on the piezoelectric slider principle. The system includes standard surface analytical techniques (low-energy electron diffraction/Auger, prepared for x-ray photoelectron spectroscopy) and is equipped for mass spectroscopic detection of reaction products from catalytic surfaces at elevated temperature. Tips are cleaned in situ using electron bombardment. By using tungsten cantilevers with a high spring constant (k=100–200 N/m), it is possible to switch directly between STM and SFM operation. As reference surface we have used the Si(111)7×7 reconstruction, prepared by in situ flashing to 1150 °C, which is imaged at atomic resolution using STM as well as ac-mode SFM. © 1996 American Institute of Physics.

Electronic Resource

1365-3083

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

A 300 b.p. promoter from the mouse joining chain (J-chain) gene was studied with regard to functional activity and protein/DNA interactions. The promoter only stimulated expression of a chloramphenicol-acetyl-transferase (CAT) reporter gene when an enhancer was present in the construct, regardless of whether the construct was transfected into cell lines that did or did not express an endogenous J-chain. Furthermore, deletion mutants lacking the 5’portion of the promoter were transcribed at a higher rate than the intact promoter in both J-chain positive and J-chain negative B-cell lines but not in untransformed B lymphocytes stimulated by lipopolysaccharide, indicating the presence of a negative control element in the 5′ portion of the J-chain promoter active in tumour cells only. The octamer element in the J-chain promoter was found to bind Oct proteins, albeit with a low affinity. The penta-deca (p.d.) element in the J-chain promoter bound proteins in extracts from untransformed B cells but not in the tested cell lines. The protein binding to the J-chain p.d, element did not compete efficiently with a. p.d. element from the SP6 k promoter. A protein binding to the 5′ portion of (he J-chain was expressed in some cell lines but not in others; neither a negative nor a positive correlation to J-chain expression could be seen. It was concluded that the J-chain promoter is equivalent to a k promoter and that differentiation-specific J-chain expression is governed by distal, positive control elements located outside the analysed region.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We present a method for in situ characterization of the tip shape in atomic force microscopes that can operate in noncontact ac mode. By sweeping the voltage between tip and sample while recording the sample position as it is regulated to give a constant force gradient, we obtain curves giving information about the tip geometry. The measurements were performed in ultrahigh vacuum using electrochemically etched tungsten tips against a surface of doped silicon. Our results show that the sphere model gives a good description of the interaction, and that the radii we obtain are consistent with data from scanning electron microscopy. The method can also be used to estimate the value of the Hamaker constant and the contact potential between tip and sample. © 1998 American Institute of Physics.

Electronic Resource

0020-1693

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

1365-3083

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Bone marrow-dervied (colony-stimulating factor [CSF]-dependent) diffuse colonies have been shown to include colonies with cytotoxic activity. Such diffuse colonies were expanded for 6–8 weeks in liquid culture medium in the presence of pokeweed mitogen- or concanavalin A-conditioned spleen cell medium (CM). The morphology of the expanded diffuse colony cells (EDCC) was like that of early myelocytic cells. EDCC lost their cytotoxic capacity when expanded, but the cytotoxicty could be reinduced by pretreatment of the colonies with interferon or phorbol ester. Traditional sources of mouse or human CSF such as lung CM, placenta CM and human mononuclear cell CM did not support proliferation of EDCC, whereas partly purified interleukin-3 (IL-3), lacking CSF and IL-2, was stimulatory for EDCC. Thus, the stimulatory factor for EDCC was not CSF but a factor closely related to IL-3. Monoclonal antibodies against T lymphocytes or macrophages did not bind to EDCC. EDCC did not have Fc receptors, but 10% of the cells were positve for a monoclonal anti-la antibody. All EDCC were positive for αNAE and NASDCI esterases but negative for acid and alkaline phosphatases and peroxidase reactivity; less than 2% of the cells showed metachromatic staining with toluidine. Ultrastructurally, EDCC showed various degrees of cell differentiation but absence of specific cytoplasmatic characteristics such as neutrophilic, eosmophilic, basophilic and mast cell granules. Current work aims to define factors and conditions necessary for the induction of differentiation in these immature monomyelocytic cells.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Dose-response data for the cytotoxicity of mass-collected cluster and colony cells from day 7 cultures show (Table 1) that a variety of syngeneic, allogeneic and xenogeneic tumour cells as well as fetal syngeneic fibroblasts are sensitive to cytotoxic attack in a ratio of target: attacker cell as ...

Electronic Resource

0891-5849

ESR ; Ischemia and reperfusion ; Nitroxyl radicals ; Small intestine ; Spin trapping ; Superoxide ; Superoxide dismutase

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Medicine

Electronic Resource

0008-6215

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0021-9673

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0021-9673

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0021-9673

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0021-9673

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0040-4039

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0014-4827

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Medicine

Electronic Resource

0531-5565

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Medicine

Electronic Resource