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Showing papers by "Boston University published in 1971"


Journal ArticleDOI
TL;DR: In this paper, the authors present a test of normality based on a statistic D which is up to a constant the ratio of Downton's linear unbiased estimator of the population standard deviation to the sample standard deviation, being appropriate to detect deviations from normality due either to skewness or kurtosis.
Abstract: SUMMARY We present a test of normality based on a statistic D which is up to a constant the ratio of Downton's linear unbiased estimator of the population standard deviation to the sample standard deviation. For the usual levels of significance Monte Carlo simulations indicate that Cornish-Fisher expansions adequately approximate the null distribution of D if the sample size is 50 or more. The test is an omnibus test, being appropriate to detect deviations from normality due either to skewness or kurtosis. Simulation results of powers for various alternatives when the sample size is 50 indicate that the test compares favourably with the Shapiro-Wilk W test, Vbl, b2 and the ratio of range to standard deviation. Shapiro & Wilk (1965) presented a test of normality based on a statistic W consisting essentially of the ratio of the square of the best, or approximately best, linear unbiased estimator of the population standard deviation to the sample variance. They supplied weights for the ordered sample observations needed in computing the numerator of W and also percentile points of the null distribution of W for samples of size 3 to 50. Subsequent investigation (Shapiro, Wilk & Chen, 1968) revealed that this test has surprisingly good power properties. It is an omnibus test, that is, it is appropriate for detecting deviations from normality due either to skewness or kurtosis, which appears to be superior to 'distance' tests, e.g. the chi-squared and Kolmogorov-Smirnov tests. It also usually dominates such standard tests as 1bl, third standardized sample moment; b2, fourth standardized sample moment; and u, ratio of the sample range to the sample standard deviation. Shapiro and Wilk did not extend their test beyond samples of size 50. A number of reasons indicate that it is best not to make such an extension. First, there is the problem of the appropriate weights for the ordered observations for the numerator of W. Each sample size requires a new set. The proliferation of tables is obvious and undesirable. However, even if the appropriate weights were computed from the expected values of the ordered observations from the standardized normal distribution (Harter, 1961), there would still be the uninviting problem of finding the appropriate null distribution of W. Because W's moments beyond the first are unknown, Cornish-Fisher expansions or similar techniques are not applicable. Further, the extension of the normal approximation for W based on Johnson's bounded curves (Shapiro & Wilk, 1968) when the sample is greater than 50 would require an extrapolation and the procedure for implementing it is not available. Simulation runs seem to be the only available way to obtain the null distribution. We present a new test of normality applicable for samples of size 50 or larger which possesses the desirable omnibus property. It requires no tables of weights and for samples of

516 citations


Journal ArticleDOI
TL;DR: A modification of the Edman degradation is described whereby peptides are degraded sequentially on a solid support by a machine, the solid-phase peptide sequencer, which is simple in design and operation, and inexpensive to construct.
Abstract: A modification of the Edman degradation is described whereby peptides are degraded sequentially on a solid support by a machine, the solid-phase peptide sequencer. Reagents are pumped through a column containing the resin-bound peptide, and the amino acid thiazolinones released after each degradative cycle are collected on a fraction collector for subsequent analysis. A complete cycle requires 2 h, and all operations are controlled automatically by a programmer. An improved peptide resin is described, to which peptides can be attached in yields ranging from about 70% for the 30 amino acid insulin B-chain to nearly 100% for smaller peptides. Of the 18 amino acids examined so far, glycine, alanine, phenylalanine, tyrosine, valine, leucine, isoleucine, proline, methionine, asparagine, glutamine, histidine, lysine, threonine, serine and cysteic acid are degraded normally; the phenylthiohydantion of threonine is partially dehydrated and that of serine is almost completely destroyed by trifluoroacetic acid, however. The phenylthiohydantion of glutamic acid is not detected, because it remains bound by its γ-carboxyl group to the resin. When aspartic acid is encountered in peptides, further degradation is completely blocked, presumably as a result of the β-carboxyl group having formed a cyclic imide. Using the sequencer and unpurified reagents, it was possible to degrade entirely a 0.24 μmole sample of the 21 amino acid insulin A-chain (oxidized) and to analyze the products within a 3-day period. Degradative yields averaged 94% per cycle. Similarly, 0.1 μmole of the insulin B-chain was degraded through 18 cycles before identification of the phenylthiohydantoins became ambiguous. The sequencer is simple in design and operation, and is inexpensive to construct. The scope and limitations of the method are discussed.

389 citations


Journal ArticleDOI
TL;DR: The premotor and arcuate regions can be differentiated on the basis of their intrahemispheric connectivity and the non-homotopic projection of the premotor areas are directed to MI, MII, and prefrontal cortex, whereas those from the arcuate areas are observed in the prefrontal cortex only.

358 citations


Journal ArticleDOI
TL;DR: The relative location of the interhemispheric cortical fibers within the corpus callosum was studied after callosal section in 7 rhesus monkeys with the silver impregnation techniques to result in strikingly dissimilar cortical projection patterns.

330 citations


Journal ArticleDOI
Rohit Parikh1
TL;DR: Could not one press further the criticism which intuitionism makes of existential assertions and raise the question: What does it mean to claim the existence of an arabic numeral for the foregoing number, since in practice the authors are not in a position to obtain it?
Abstract: “From two integers k, l one passes immediately to kl; this process leads in a few steps to numbers which are far larger than any occurring in experience, e.g., 67(257729).Intuitionism, like ordinary mathematics, claims that this number can be represented by an arabic numeral. Could not one press further the criticism which intuitionism makes of existential assertions and raise the question: What does it mean to claim the existence of an arabic numeral for the foregoing number, since in practice we are not in a position to obtain it?

294 citations


Journal ArticleDOI
TL;DR: Results of a reexamination 1 year later of 10 subjects whose role-taking and moral-judgment levels were low in the original study supported the hypothesis that the development of the ability to understand the reciprocal nature of interpersonal relations is a necessary but not suficient condition for theDevelopment of conventional moral thought.
Abstract: SELMAN, ROBERT L. The Relation of Role Taking to the Development of Moral Judgment in Children. CHILD DEVELOPMENT, 1971, 42, 79-91. In order to explore the relationship in middle childhood between two socialcognitive processes, role-taking ability and moral reasoning, 60 middle-class children (10 boys and 10 girls each at ages 8, 9, and 10) were administered Kohlberg's (1963) moral-judgment measure, two role-taking tasks, and the Peabody Picture Vocabulary Test, a conventional measure of intelligence. Results indicated that at this age range, with intelligence controlled, the development of reciprocal role-taking skills related to the development of conventional moral judgment. Results of a reexamination 1 year later of 10 subjects whose role-taking and moral-judgment levels were low in the original study supported the hypothesis that the development of the ability to understand the reciprocal nature of interpersonal relations is a necessary but not suficient condition for the development of conventional moral thought.

266 citations


Book ChapterDOI
Donald Small1
01 Jan 1971
TL;DR: It is the belief of this author that the physicochemical characteristics of bile salts and their molecular interactions with other lipids, proteins, and complex carbohydrate molecules probably account for not only the physiological properties of biles salts but also the pathological conditions attributed to them.
Abstract: The conjugated bile acids are biologically the most important detergentlike molecules (1). They solubilize the insoluble components of bile, such as lecithin and cholesterol (2–9), aid in digestion by removing the products of pancreatic hydrolysis (monoglycerides and fatty acids) (10–12), and probably control certain intracellular events such as the synthesis of cholesterol in the intestinal mucosa (13). In certain cases, secondary bile salts may be toxic to cells and may cause cholestasis and hepatic necrosis (14–26). It is the belief of this author that the physicochemical characteristics of bile salts and their molecular interactions with other lipids, proteins, and complex carbohydrate molecules probably account for not only the physiological properties of bile salts but also the pathological conditions attributed to them.

261 citations


Journal ArticleDOI
TL;DR: The findings indicate that the syndrome of heart failure following chronic tachycardia, characterized by elevatedleft ventricular end-diastolic pressure and ascites, is associated with significant depression of the left ventricular contractile state and total energy stores.

222 citations


Journal ArticleDOI
TL;DR: The shape and fine structure of ventricular (primitive ependymal) cells during their generation cycle was studied and it was found that microfilaments are present in telophase cells before outgrowth of external processes and in growing tips of internal processes.
Abstract: The shape and fine structure of ventricular (primitive ependymal) cells during their generation cycle was studied. Interphase cells are radially oriented bipolar elements with processes spanning the thickness of the brain wall. Zonular junctional complexes joining internal processes at the ventricle consist of gap junctions and wider intermediate junctions. The external limiting layer consists of expanded end-feet in simple apposition; they resemble axonal growth cones and contain a feltwork of 60 A microfilaments, elements of smooth endoplasmic reticulum but no microtubules. During prophase, nuclei of ventricular cells move to a juxtaventricular position, while their external processes remain fully extended. The internal processes of such cells contain numerous longitudinally arranged microtubules and microfilaments. Subsequent to nuclear migration, in prometaphase or metaphase, the cell withdraws or pinches off its external process and becomes nearly spherical. During telophase an asymmetrical furrow formation results in a thin connector (midbody) between daughter cells which is adjacent to the ventricle and attached there by the junctional complex. Either before or after complete separation, an external process starts regrowing towards the external limiting layer, eventually resulting in a bipolar interphase cell again. Microfilaments are present in telophase cells before outgrowth of external processes and in growing tips of external processes.

222 citations


Journal ArticleDOI
TL;DR: The finding that the free fatty acids (FFA) in scalp lipids were proportional to the level of C. acnes suggests that these organisms are the chief source of lipolytic enzymes.

213 citations


Journal ArticleDOI
TL;DR: Focal pressure, applied to the skin over bone, is a method of evoking experimental pain of an “aching” nature in which actual receptor stimulation is closely related to the applied stimulus.
Abstract: Focal pressure, applied to the skin over bone, is a method of evoking experimental pain of an “aching” nature in which actual receptor stimulation is closely related to the applied stimulus. Methodological faults in previous applications of this method are eliminated by a pain stimulator which utilizes a bonded strain gauge.

Journal ArticleDOI
TL;DR: In this article, the efferent cortical projections of the prefrontal cortex were studied in rhesus monkeys using silver impregnation techniques and it was shown that different sectors of prefrontal cortex, in particular the principal sulcus, show preferences for specific cortical regions.


Journal ArticleDOI
24 Nov 1971-Nature
TL;DR: The proteins synthesized by growing neurones are examined in the hope that there would be components the authors could identify and, perhaps, to which they could assign a role in neurite assembly.
Abstract: AXONAL growth from developing and regenerating nerve cells is a very rapid process. The growth rate is often as high as 50 µm/h1 and the axon that emerges from a cell less than 0.1 mm in diameter can have a final length of more than a metre. Such a vigorous process, occurring in a non-dividing cell, will probably dominate the biosynthetic activity of the neurone and it is likely that proteins made in large amounts will be major components of the growing fibres. For this reason we have examined the proteins synthesized by growing neurones in the hope that there would be components we could identify and, perhaps, to which we could assign a role in neurite assembly. We have used explanted neurones growing in tissue culture because they can be obtained largely free of other cell types; and we have chosen embryonic sympathetic neurones because of the extremely rapid outgrowth of processes which can be induced by addition of the nerve growth factor (NGF)2.

Book
Rudolf Arnheim1
01 Jan 1971
TL;DR: I Useful order Reflections of physical order Disorder and degradation What the physicist has in mind Information and order Probability and structure Equilibrium Tension reduction and wear and tear The virtue of constraints The structural theme II Order in the second place The pleasures of tension reduction Homeostasis is not enough A need for complexity Art made simple Call for structure Bibliography Index as discussed by the authors
Abstract: I Useful order Reflections of physical order Disorder and degradation What the physicist has in mind Information and order Probability and structure Equilibrium Tension reduction and wear and tear The virtue of constraints The structural theme II Order in the second place The pleasures of tension reduction Homeostasis is not enough A need for complexity Art made simple Call for structure Bibliography Index

Journal ArticleDOI
TL;DR: Autoradiographic and morphologic studies indicate neuroglial proliferation during the first two weeks of degeneration can account for the numerical increase of cells in optic nerves undergoing Wallerian degeneration.
Abstract: Young adult rats were injected with tritiated thymidine, either before or after removal of one eye, to investigate: (1) the possibility of a leukocytic infiltration into degenerating optic nerve during the first six days following the operation, (2) the origin of the increased number of cells seen in degenerating tissue during the first few weeks after operation, and (3) the possibility of a change in the generation pattern of neuroglial cells in degenerating tissue. In order to investigate the possibility of a leukocytic invasion, rats were injected three times before enucleation to label a high percentage of circulating leukocytes while only labeling a few neuroglial cells. On the operated side of these animals, a small increase in the number of labeled cells above control values occurs only on the third day following enucleation. Another experiment shows that this increase can be explained by a change in the genratiion pattern of the neuroglial cells from two to four days postoperative (2–4 d.p.o.). In degenerating optic nerves, the number of labeled neuroglial cells increase almost tenfold in a 28 hour period from 2–3 d.p.o. While a week is required for a similar increase in normal optic nerve. From 1–3 d.p.o., astrocytes and astrocyte-like cells constitute 30–50% of the labeled cells observed in a pulse label while the remainder of the labeled cells (unclassifiable neuroglia) cannot be categorized as either astrocytes or oligodendrocytes in light micrographs. Our autoradiographic and morphologic studies indicate neuroglial proliferation during the first two weeks of degeneration can account for the numerical increase of cells in optic nerves undergoing Wallerian degeneration. There is no evidence for an important infiltration of leukocytes and/or pericytes into the optic nerve.



Journal ArticleDOI
TL;DR: Autoradiography of the brain indicated that angiotensin penetrates into the cerebrospinal fluid from the blood, and the volume of distribution was significantly larger than the plasma volume but smaller than thevolume of distribution of inulin.

Journal ArticleDOI
TL;DR: It is emphasized that low concentrations of asbestos can lead to pulmonary fibrosis and supports the need for lower threshold limit values.
Abstract: Low-level asbestos exposure, as occurs in pipe coverers in new ship construction, has not been considered dangerous. We surveyed 101 such workers and 94 controls matched for age, duration of employment and smoking habits in a New England yard. Dust exposure, under surveillance for 20 years, had been near the then recommended threshold limit value of 5 million particles per cubic foot (mppcf). "Asbestosis" was defined by presence of three or more of five standardized clinical abnormalities including dyspnea, rales, finger clubbing, reduced vital capacity and x-ray shadows. The latter were judged by three observers unaware of the exposure history. "Asbestosis" was 11 times more common among pipe coverers than among controls; it was found first after 13 years of exposure or 60 mppcf-years, and the prevalence was 38 per cent after 20 years. This study emphasizes that low concentrations of asbestos can lead to pulmonary fibrosis and supports the need for lower threshold limit values.

Journal ArticleDOI
TL;DR: Discs and amorphous material derived from membrane-coating granules coat and thicken the plasma membrane by modifying the outer leaflet, and thus may play a role in the barrier function of the stratum corneum.
Abstract: Membrane-coating granules are found in close association with the Golgi apparatus, and their apparent size, shape and internal substructure varies with the plane of section. After a membrane-coating granule is discharged into the intercellular space, it dissociates into distinct units, the pentalamellar discs, which are stacked like coins in the intact granule. Subsequently, discs become applied to and appear to fuse with the outer leaflets of the horny cell membranes, resulting in the formation of a nine-layered membrane-disc complex. When this complex cleaves at the junction of the thick dense lamella and distal lighter lamella of the disc, a pentalaminar horny-cell surface membrane results. The more common surface membrane, however, is trilaminar consisting of thickened inner leaflet, lighter middle leaflet, and thickened outer leaflet. The thickened outer leaflet may result from the addition of amorphous intercellular material derived from membrane-coating granules or from the fusion of two outer leaflets, as in the formation of a tight junction. The thickened inner leaflet results from the deposition of dense material onto the cytoplasmic face of the inner leaflet; there exists a regional variation in its dimensions. The side of the cell facing the surface of the epithelium has a thickened inner leaflet varying in width between 140 and 180 A, whereas the side facing the underlying cell is only about 100 A thick. Discs and amorphous material derived from membrane-coating granules coat and thicken the plasma membrane by modifying the outer leaflet, and thus may play a role in the barrier function of the stratum corneum.

Journal ArticleDOI
TL;DR: Results showed that the span of retention for Korsakoff patients deteriorated significantly faster than either of the two non-brain-damaged groups for materials consisting of either CCC's, one-word or three-words.

Journal ArticleDOI
TL;DR: Evidence is presented that in the duodenum of fetal rats, DNA synthesis and cell proliferation occur in epithelial cells along the entire length of the villi and that this unique pattern of cell renewal changes shortly before birth.
Abstract: Radioautographic studies with the labeled desoxy-ribonucleic acid (DNA) precursor, tritiated thymi-dine, have shown that cell proliferation in mam-malian small intestinal epithelium normally is confined to the crypts (I). Following their formation in the crypts, most epithelial cells migrate onto the villi where they lose their capacity to proliferate as they mature into functional absorptive cells. Such restriction of cell proliferation to the crypts has been demonstrated in both adult rats (1, 2) and in young animals 7 days of age (3) and older (4). In fetal rats, formation of villi begins at the 17th day of gestation, and tall, well-developed villi have formed in the proximal intestine by the 19th day of gestation. In contrast, discrete, well-defined crypts do not develop until shortly after birth (5, 6, 7). In this report, we present evidence that in the duodenum of fetal rats, DNA synthesis and cell proliferation occur in epithelial cells along the entire length of the villi and that this unique pattern of cell renewal changes shortly before birth. Fetal and newborn rats from timed pregnant Sprague-Dawley albino rats were studied from the 19th day of gestation through 1 day after birth. Newborn animals were born on the afternoon of the 22nd day of gestation and were injected immediately after birth. For the study of fetal animals, a dose of 225-250 #Ci of thymidine-SH (SA 6.7 Ci/mmole; New Eng-land Nuclear Corp., Boston, Mass.) was injected into the tail vein of the pregnant females; for the newborn rats, a dose of 15-20 #Ci of thymidine-SH was injected intraperitoneally. Segments of duodenum were removed from fetal and newborn animals 1.5 hr later. After fixation in chilled chrome osmium fixative (8), the tissue was embedded in epoxy resin and sections 1 # thick were mounted on glass slides. These were dipped in Ilford K-5 emulsion (Ilford Ltd., Ilford, Essex, England), exposed for 4-8 wk, developed , and stained with toluidine blue (9, 10). In addition, thin sections were cut and stained with heavy metals for electron microscope studies (1 I). Radioautographs of duodenum obtained from 19-and 20-day fetuses and from one litter of 21-day fetuses 1.5 hr after thymiciine-SH injection revealed a predominance of labeled nuclei in epithelial cells located between villi and at the extreme base of the villi (Figs. I and 2), that is, at the site of future crypts. However, there was also significant labeling of nuclei in epithelial cells …

Journal ArticleDOI
Alan Peters1
TL;DR: Perikaryal cytoplasm is thick, the granular endoplasmic reticulum is often arranged in parallel arrays, and the type of synapse with a side cleft and a prominent postsynaptic density is most common.
Abstract: Stellate cells have rounded or oval cell bodies which contain nuclei bounded by a ruffled, and frequently indented, nuclear envelope. Te cytoplasm of these neurons is usually darker than that of pyramidal neurons because it contains a greater concetration of ribosomes. Where the perikaryal cytoplasm is thick, the granular endoplasmic reticulum is often arranged in parallel arrays. On the surface of the perikarya are three types of synapses: (1) ones with a wide cleft and a prominent postsynaptic density, (2) ones with a wide and straight synaptic cleft that lack a prominent postsynaptic density, and (3) ones with a narrow synaptic cleft and short synaptic complexes. The dendrites of stellate cells lack spines and frequently bear many synapses. On the thinner dendritic branches the type of synapse with a side cleft and a prominent postsynaptic density is most common. The cytoplasm of the dendrites is characterized by closely arranged microtubules.

Journal ArticleDOI
TL;DR: The pharmacokinetics of cyclophosphamide were investigated in cancer patients in a two-compartment open model and the calculated fraction of the dose of drug which was metabolized averaged 88%.
Abstract: 1. The pharmacokinetics of cyclophosphamide were investigated in cancer patients. The data can be characterized by a two-compartment open model. The half life of the elimination phase of the drug ranged between 3 and 11 hours. 2. Extensive tubular reabsorption of the drug resulted in the excretion of only a small percentage of the administered dose. The mean renal clearance was 10·7 ml/minute. 3. The calculated fraction of the dose of drug which was metabolized averaged 88%.

Journal ArticleDOI
09 Apr 1971-Nature
TL;DR: It is found that repeated, topical applications of DMSO extracts of betel nut to the mucosa of the buccal pouch of hamsters result in the development of leukoplakia and tumours.
Abstract: THE high incidence of oral cancer in the Far East is generally attributed to the habitual use of betel nut “quids” which may contain, as well as betel nut, cured tobacco and various other organic and inorganic materials1–4. Attempts to extract from betel nut a material carcinogenic for oral tissues have not been successful5,6, possibly because extracts were prepared with solvents in which the carcinogenic materials were not soluble. We have therefore extracted betel nut, alone or in combination with cured tobacco, with dimethyl sulphoxide (DMSO) and applied the extracts in this vehicle. Our choice of DMSO was based on the evidence that it is an excellent solvent with a low toxicity7, that it has great powers of penetration8 and that it enhances the absorption of various drugs through skin and mucous membranes without apparently affecting their pharmacological properties9–12. Furthermore, the use of DMSO as a vehicle decreases the latency period for the production of oral tumours in hamsters with dimethylbenzanthracene13–14. We have found that repeated, topical applications of DMSO extracts of betel nut to the mucosa of the buccal pouch of hamsters result in the development of leukoplakia and tumours. The incidence of tumours increases when the extract is made from a mixture of betel nut and cured tobacco, although extracts of tobacco alone cause leukoplakia but not tumours.

Journal ArticleDOI
TL;DR: 18-Hydroxy-ll-deoxycorticosterone (18-OH-DOC) was isolated from human adrenal vein blood in concentrations of the same magnitude as is aldosterone, and its structure was proved by a variety of methods including mass spectral analysis.
Abstract: 18-Hydroxy-ll-deoxycorticosterone (18-OH-DOC) was isolated from human adrenal vein blood in concentrations of the same magnitude as is aldosterone, and its structure was proved by a variety of meth...

Journal ArticleDOI
TL;DR: The work of Lunney (1970) concerning the appropriateness of analysis of variance (ANOVA) techniques on dichotomous data is discussed and extended in this paper, and relations between standard statistical techniques for analyzing dichotomyous data and ANOVA procedures are indicated.
Abstract: The work of Lunney (1970) concerning the appropriateness of analysis of variance (ANOVA) techniques on dichotomous data is discussed and extended. Relations between standard statistical techniques for analyzing dichotomous data and ANOVA procedures are indicated. The need for usefulness of analyzing transformed data as opposed to direct analysis of dichotomous data are discussed. Required statistical procedures employing transformed data are outlined.

Journal ArticleDOI
TL;DR: This study suggests that reliable guides to myocardial contractility can readily be obtained from high fidelity pressure recordings alone.
Abstract: The index V pm (the actual or physiologic maximal shortening velocity of the contractile element) has been obtained from the analysis of left ventricular pressure recordings and then applied to the assessment of myocardial contractility in man Pressures during the isovolumic period of ventricular systole were recorded during routine catheterization of 46 patients with a variety of cardiac lesions The quantity V pm , that is (dp/dt/kp) max , was compared with the hemodynamic evaluation of each patient based on the left ventricular end-diastolic pressure, ejection fraction and left ventricular end-diastolic volume V pm was selected for this study since it appeared to be largely independent of load and does not require biplane angiocardiography and extrapolation analyses Preliminary results suggest that a value of V pm greater than 16 sec −1 indicates normal myocardial function; lower values indicate abnormal function In several instances this index was not in agreement with the hemodynamic measures, but in most cases the clinical assessment supported the conclusion drawn from V pm This study suggests that reliable guides to myocardial contractility can readily be obtained from high fidelity pressure recordings alone

Journal ArticleDOI
TL;DR: The results are consistent with the concept that vasodilatation is associated with an increase and vasoconstriction with a decrease, in 3 H-cyclic AMP levels in vascular smooth muscle.