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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 3556-3563 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The torsion balance has been the experimental apparatus of choice for centuries, both in precision measurements of the Newtonian gravitational constant and in searches for weak anomalous interactions outside of gravity. If the form of the interaction is modeled, it is often possible to optimize the interacting bodies so that the apparatus has the greatest sensitivity to the interaction under study. Other researchers have applied this strategy in the case of the gravitational interaction between cylinders, and between a cylinder and sphere. Whereas their work focused on developing an analytical expression for the force between the masses, we present here a numerical method−Monte Carlo integration−which is general enough to aid in the design of bodies interacting under arbitrary potentials and with any desired geometric shape (as long as an accurate absolute value of the force is not needed). This numerical method is used to compute the gravitational torsion constant produced between an external hollow cylinder and sphere, and demonstrates the behavior studied previously through analysis. However, the main purpose for which we have used this numerical technique is in the design of interacting bodies used in a torsion-pendulum search for interactions that depend on net intrinsic spin. We demonstrate how the method may be used to determine the optimum aspect ratio (l/r) of the polarized test masses, as well as the most sensitive orientation of the masses. Two different interactions are considered: the dipole–dipole interaction between two polarized bodies, and the monopole–dipole interaction between a polarized and unpolarized body. In the case of the monopole–dipole interaction, we also show how the numerical method can indicate which orientation between test bodies is most susceptible to a false signal caused by gravity.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 57 (1986), S. 3019-3023 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A method for measuring the force arising from the attraction between a charged electrode and another electrode on which charges have been induced has been developed using a torsion balance operated in the ac mode far above the resonance frequency of the balance. The movement of the balance is sensed by a capacitive position transducer which uses two lock-in amplifiers to demodulate the position signal. The balance itself and the position transducer are described. The sensitivity of the position transducer is given, and results from three electrode geometries are discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1440
    Keywords: Diabetes mellitus ; Long-term diabetes ; Lipoproteins ; Apolipoproteins ; HDL cholesterol ; Triglycerides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary All diabetic patients suffering from the disease for at least 20 years and living in the closed area of the Erfurt district in 1970 have been followed prospectively since that time. In 47 of them still alive in 1985, i.e. after more than 35 years of diabetes, serum lipid and apolipoprotein concentrations were measured and compared to those of non-diabetic subjects without cardiovascular diseases (n=47) pair-matched by sex, age, and body weight. In males (n=27) significantly (p〈0.01) higher levels of HDL cholesterol and apolipoprotein A–I as well as lower concentrations of triglycerides and a lower total cholesterol/HDL cholesterol risk ratio than in nondiabetic control subjects could be found. In long-term diabetic females (n=20), apolipoprotein A–I levels were also increased (p〈0.02). Trends in HDL cholesterol and triglycerides were similar to those found in males but did not reach statistical significance. Higher concentrations of total cholesterol (p〈0.02), LDL cholesterol (P〈0.05), and apolipoprotein B (p〈0.02), however, did not fit in with a beneficial lipoprotein pattern. The frequency of pathological lipoprotein patterns was not higher than among the non-diabetic control subjects (32% and 40%, respectively). According to these findings an antiatherogenic lipoprotein pattern might be considered, at least in males, as one of the determinants causing the multifactorial event of long-term survival in diabetes.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopic investigations on the involvement of the fetal membranes of the rat (visceral yolk sac) in the lipid metabolism revealed the occurrence of lipoprotein-sized particles located in cisternal Golgi stacks, Golgi vesicles and secretory vesicles of the cells of the visceral yolk sac epithelium as well as in distended areas of the intercellular space between adjacent epithelial cells. Application of the protein A-gold technique with specific anti-apoB antiserum resulted in a specific location of immunogold both over the different compartments of the lipoprotein pathway (RER, Golgi complex, secretory vesicles) as well as over the distended intercellular spaces, thus confirming these particles to be lipoproteins in nature. Isolated visceral epithelial cells prepared by a tryptic digestion method exhibited some ultrastructural alterations, such as a loss of apical brush border, a change from columnar to spherical cell shape, a decrease in phagolysosomes, but an increase in autophagosomal structures after 6 h incubation at a vitality rate of at least 85%. Within this period the epithelial cells secreted measurable amounts of apoB-containing lipoproteins into the medium floating in the density classes d〈1.006 g/ml, d=1.006–1.020 g/ml and d=1.020–1.064 g/ml. The production of the lipoproteins was partly inhibited by cycloheximide indicating the secretion of particles with preformed as well as newly synthesized apoB. Negative staining of the particles revealed an average diameter of 34 nm of VLDL, 31 nm of IDL and 24 nm of LDL. In summary, our studies demonstrate that in the feto-placental unit of the rat the fetal membranes are capable of synthesizing and secreting lipoproteins. The cells of the visceral yolk sac epithelium were shown to be the producers of apoB-containing particles.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 84 (1990), S. 361-364 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The association of various unsystematic aneuploidies with premature centromere division (PCD) was observed in a patient with conspicuous clinical features and combined immunodeficiency. Trisomies and monosomies of almost all autosomes and gonosomal aberrations were found separately or in combination in a majority of the proband's lymphocytes and fibroblasts. The chromosome number varied from 44 to 50. A high proportion of the metaphases showed PCD or had the appearance of C-anaphases. These findings probably represent a new mutant affecting mitosis and causing mosaic aneuploidies.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 152 (1993), S. 244-249 
    ISSN: 1432-1076
    Keywords: Nephropathic cystinosis ; Growth ; Puberty
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In a retrospective investigation growth and pubertal development were evaluated in 30 patients with nephropathic cystinosis. Growth was investigated during the stage of chronic renal insufficiency as well as after successful kidney transplantation and growth rates were related to kidney function. Pubertal development was evaluated in 17 patients between 12 ans 25 years of age. Prepubertal growth rates were stable in a range between −2 and −3 height velocity SDS as long as glomerular filtration rate was above 20ml/min per 1.73m2. A decrease in glomerular filtration rate below this threshold was followed by further decrease in height velocity. After kidney transplantation a significant catch-up growth was seen if immunosuppression was performed with cyclosporine A and lowdose prednisolone. This did not occur if conventional therapy with azathioprine and high-dose prednisolone was used. Onset of puberty was delayed in all patients. Gonadotropin and oestradiol levels in female patients showed normal fluctuations according to ovulatory cycles. In male patients after puberty there was an increase in gonadotropin levels above the normal range for adult men while testosterone levels remained in the low normal range. These results indicate that adult men with nephropathic cystinosis may develop hypergonadotropic hypogonadism.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1076
    Keywords: Pyruvate dehydrogenase deficiency ; Hyperammonaemia ; Peritoneal dialysis ; Lipoic acid ; Plasma amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 2-day-old girl developed a severe lactic acidosis with a normal lactate/pyruvate ratio and hyperammonaemia. Plasma arginine and citrulline levels were below the limit of detection. In muscle total pyruvate dehydrogenase complex (PDHC) and pyruvate decarboxylase (E1) activities were reduced to a fraction of lower control values. The acute neonatal period was bridged with peritoneal dialysis, dichloroacetate therapy, supplements of arginine and branched chain amino acids, a complete vitamin B complex and lipoic acid. Lactate homeostasis responded to pharmacological supplements of lipoic acid. At age 1 year the child was hypotonic, showed severe developmental retardation, optic atrophy and cranial dysmorphism. She died aged 1 year 8 months with signs of respiratory paralysis but with normal lactate levels under assisted breathing. Pathological findings at autopsy were suggestive of Leigh syndrome, interstitial pneumonia and extensive fatty infiltration of hepatocytes. Regression analysis of data from 187 plasma amino acid determinations from the patient over a period of 1 year 8 months revealed a persistent imbalance involving alanine, glutamic acid, glutamine, proline, citrulline and branched chain amino acids. Aspects of acute and long-term therapy in this patient and some implications of the imbalances in plasma amino acids are discussed.
    Type of Medium: Electronic Resource
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