Institutions, Social Norms, and Bargaining Power: An Analysis of Individual Leisure Time in Couple Households

We exploit time use data from Denmark and the United States to examine the impact institutions and social norms have on individuals' bargaining power within a household, hypothesizing that the more generous social welfare system and more egalitarian social norms in Denmark will mitigate the impact standard economic power measures have upon couples' time use. Further we posit that leisure time will be more sensitive to power considerations than housework time which may be more influenced by preferences regarding household public goods, to gendered notions of time use, and to censoring. Our results are generally supportive of these hypotheses, with leisure time on non-work days in the US being particularly responsive to economic power. In addition, we find some evidence that institutions matter as women in the US who are more likely to receive welfare benefits enjoy more leisure time than would be suggested by their economic power alone.Time Use, Power, Leisure, Institutions, Norms

Does microsomal glycerophosphate acyltransferase also catalyze the acylation of dihydroxyacetone phosphate?

Rat liver microsomal dihydroxyacetone phosphate acyltransferase, in contrast to the glycerophosphate acyltransferase, was found to be active at low pH (5.5), stable towards heat (55 [deg]C, 15 min) and trypsin (in the absence of detergents) and was not inhibited by high concentrations of N-ethyl maleimide. Dihydroxyacetone phosphate acyltransferase is only slightly and non-competitively inhibited by sn-glycerol-3-phosphate whereas glycerophosphate acyltransferase is strongly inhibited by dihydroxyacetone phosphate in a competitive manner. Kinetic analysis indicates that this competitive inhibition is not due to the competition of two common substrates for the same active center of one enzyme. These results demonstrate that microsomal glycerophosphate acyltransferase and dihydroxyacetone phosphate acyltransferase are two distinct and separate enzymes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24662/1/0000075.pd

Properties of the enzymes catalyzing the biosynthesis of lysophosphatidate and its ether analog in cultured fibroblasts from Zellweger syndrome patients and normal controls

The activities, properties, and steady-state kinetics of the five enzymes catalyzing the synthesis of 1-acyl- and 1-alkyl-sn-glycerol 3-phosphate in the cultured skin fibroblasts from Zellweger syndrome patients and normal controls were studied in detail. Judging from their Km and Vmax values, glycerol phosphate acyltransferase (EC 2.3.1.15), acyl/ alkyl dihydroxyacetone phosphate reductase (EC 1.1.1.101), and acyl coenzyme A reductase (long-chain alcohol forming), appear to be affected only slightly by the absence of peroxisomes characteristic of the Zellweger syndrome. Glycerophosphate acyltransferase also showed no differences in N-ethylmaleimide sensitivity nor in inhibition by dihydroxyacetone phosphate between these cell types. Dihydroxyacetone phosphate acyltransferase (EC 2.3.1.42) and alkyl dihydroxyacetone phosphate synthase (EC 2.5.1.26) have altered activity and kinetic constants in homogenates from Zellweger syndrome fibroblasts. Dihydroxyacetone phosphate acyltransferase has similar Km (DHAP) values in both control and Zellweger syndrome cells; however, the value for the Vmax in Zellweger syndrome cells is only 6% of that found in the controls. This is interpreted as indicating that this enzyme is not defective in this disease but is simply present at a depressed level. Also, this enzyme activity has a maximum rate at pH 7.0-7.5 in the mutant cells as opposed to pH 5.4 in the controls. Acylation of dihydroxyacetone phosphate by control cell homogenate was stimulated by N-ethylmaleimide at both pH 5.7 and 7.5 whereas this activity from Zellweger syndrome cells was slightly inhibited at pH 5.7 and strongly inhibited at pH 7.5. In the absence of detergent, dihydroxyacetone phosphate acyltransferase in the Zellweger syndrome cells was much more labile to trypsin than in the control cells. Alkyl dihydroxyacetone phosphate synthase had a slightly higher Km(33 vs 17 [mu]) for palmitoyl dihydroxyacetone phosphate and a lower Vmax (0.07 vs 0.24 mU/mg protein) in the Zellweger syndrome cells as compared to controls. Although this is a substantial decrease in activity, it probably contributes little to the decreased rate of ether lipid synthesis in these cells. The major problem in this respect is apparently the loss of dihydroxyacetone phosphate acyltransferase activity. All of these enzymes, in both control and Zellweger syndrome cell homogenates, are sedimentable by centrifugation at 100,000g. Also, with the exception of dihydroxyacetone phosphate acyltransferase they had similar patterns of inactivation by heat in both cell types.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26724/1/0000274.pd

Zellweger syndrome: Diagnostic assays, syndrome delineation, and potential therapy

Patients with the cerebrohepatorenal syndrome of Zellweger lack peroxisomes and certain peroxisomal enzymes such as dihydroxyacetone phosphate acyltransferase in their tissues. Deficiency of this enzyme, which is necessary for glycerol ether lipid synthesis, provides a biochemical method for recognizing patients with subtle manifestations of Zellweger syndrome and suggests the utility of exogenous ether lipid precursors as a therapeutic strategy for these children. We describe the results of glycerol ether lipid supplementation to two children, one with classic Zellweger syndrome and 9% of control fibroblast dihydroxyacetone phosphate acyltransferase activity, and one with mild facial manifestations, wide sutures, hypotonia, developmental delay, hepatomegaly, peripheral retinal pigmentation, and 50% of control fibroblast dihydroxyacetone phosphate acyltransferase activity. An increase in erythrocyte plasmalogen levels following therapy was clearly demonstrated in the milder patient, and neither patient showed evidence of toxicity. Evaluation of therapy by comparison to the usual clinical course of Zellweger syndrome was not helpful because of the variability and incomplete documentation of 90 previously reported cases. The literature survey did provide criteria for classic Zellweger syndrome, which include hypotonia with or without deformation of limbs, large fontanels and split sutures, prominent forehead, flattened facial profile with hypoplastic supraorbital ridges, anteverted nares, highly arched palate, cryptorchidism or labial hypoplasia, hepatomegaly or elevated liver enzymes, peripheral pigmentation of the retina, renal cortical cysts, and characteristic neuropathology involving decreased myelinization, abnormal neuronal migration, and sudanophilic macrophages. Less severe patients, as exemplified by our case 2 and others from the literature, will not have all the classic features and can be recognized only by a growing panel of biochemical indicators. Our patient studies illustrate the complexity of designing comprehensive therapy for Zellweger-like conditions, suggest other diseases that may involve peroxisomal alterations, and emphasize the need for multicenter, collaborative studies to evaluate biochemical heterogeneity and therapy of peroxisomal disorders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38241/1/1320240109_ftp.pd

Myopathy in an infant with a fatal peroxisomal disorder

An infant with neonatal adrenoleukodystrophy experienced extreme hypotonia and virtually continuous convulsions at four months of age and died. Light and electron microscopic examination revealed evidence of myopathy and the presence of mitochondrial inclusions. Concentrations of very long-chain fatty acids were elevated in blood and fibroblasts and the oxidation of 14C-labeled fatty acids was defective. Urinary pipecolic acid content was increased. Activity of the peroxisomal dihydroxyacetone phosphate acyltransferase, which catalyzes the first step in plasmalogen synthesis, was decreased.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26173/1/0000252.pd

Hydroelastic Response of Marine Structures to Impact-induced Vibrations. Hydroelastic Reponse of Marine Structures to Impact-induced Vibrations.

This research deals with the numerical analysis of the hydroelastic behavior of marine vessels under hydrodynamic impact loads, which causes potentially detrimental local flexural vibrations in the vessel. The objective is to provide the dynamic response spectra for transient water-structure dynamics subject to typical impact loads and time scales, using one-way coupling between the fluid and the structure. The hydrodynamic pressure is assumed to be applied on the rigid plate, and then the plate is modelled to respond elastically. The structural vibrations are assumed not to influence the hydrodynamic pressure field. The changing wetted surface is the prime complexity of the problem. The sweeping load sets the plate into small amplitude vibrations, exciting all its natural frequencies (fundamental and overtones). The time-scales of the problem are : (a) the duration of the forcing when sweeping across the plate, and (b) the natural period of the structure. Assuming small deflections of the structure, normal mode summation is used to calculate the vibratory response. The total deflection is assumed to be a series summation of the modal deflections. When the amplitude of the vibrations is small, the dynamic stresses are directly proportional to the flexural displacement. Two configurations of the moving load, i.e. (i) uniform stretching load and (ii) impact load, are applied. The coupled system of modal governing differential equation is non-dimensionalized in space and time, and the Dynamic Loading Factor (DLF) of the loading is numerically evaluated by the fourth-order Runge-Kutta method. The corresponding static deflections are calculated by Galerkin's method. The ratio of the maximum dynamic deflection to the maximum static deflection is the DLF. This analysis provides recommendations to the structural designer, who typically relies on static analysis. The modal participation spectra relative to the dominant fundamental mode for various impact speeds is used to establish modal truncation guidelines. The variation of the response with respect to space and time, and with respect to various parameters like the aspect ratio, damping ratio, boundary conditions, and deadrise angles has been studied. The change in natural frequencies of the structure due to these parameters, and immersion, has also been evaluated.Ph.D.Naval Architecture & Marine EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/78773/1/ndatta_1.pd

Parathyroid Hormone-Related Peptide: A Novel Endocrine Cardioprotective Conditioning Mimetic .

An as-yet limited body of evidence suggests that calcium-regulating endocrine hormones—in particular, parathyroid hormone–related peptide (PTHrP)—may have unappreciated cardioprotective effects. The current review focuses on the concept that PTHrP may, via modulation of classic cardioprotective signaling pathways, provide a novel strategy to attenuate myocardial ischemia–reperfusion injury.</jats:p

The Impact of Worker and Establishment-level Characteristics on Male-Female Wage Differentials: Evidence from Danish Matched Employee-Employer Data

This paper examines how the segregation of women into certain occupations, industries, establishments, and job cells impacts the gender wage differential of full-time, private sector workers in Denmark. We use matched employer and employee data that contain labor market information for the Danish population. This enables us to document, for the first time, the wage impacts of gender segregation at the level of establishment and job cell in Denmark. We estimate the wage effects of gender segregation at the above four levels through fixed effects or through controls for the proportion of females within the four structures. We find that occupation has a much larger role than industri or establishment in accounting for the gender gap in full-time private sector wages in Denmark. In addition, men and women earn different wages within job cells.Women and employment; Wages; Denmark