bluuebunny/crossref_metadata_2025_split huggingface dataset:
16α-Bromoepiandrosterone, an Antimalarial Analogue of the Hormone Dehydroepiandrosterone, Enhances Phagocytosis of Ring Stage Parasitized Erythrocytes: a Novel Mechanism for Antimalarial Activity
Authors: Ayi Kodjo , Giribaldi Giuliana , Skorokhod Aleksei , Schwarzer Evelin , Prendergast Patrick T. , Arese Paolo 
Published: September 2002

ABSTRACT

Dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEA-S), which are the most abundant hormones secreted by the adrenal cortex and are present in plasma at approximately 6 μM, as well as their analogue, 16α-bromoepiandrosterone (EPI), exerted antimalarial activities against two chloroquine-sensitive
Plasmodium falciparum
strains (Palo Alto, 50% inhibitory concentration [IC
50
] of EPI, 4.8 ± 0.68 μM; T996/86, IC
50
of EPI, 7.5 ± 0.91 μM, and IC
50
of DHEA-S, 19 ± 2.6 μM) and one mildly chloroquine-resistant strain (FCR-3, IC
50
of EPI, 6.5 ± 1.01 μM). Both EPI and DHEA/DHEA-S are potent inhibitors of glucose-6-phosphate dehydrogenase (G6PD), and G6PD deficiency is known to exert antimalaria protection via enhanced opsonization and phagocytosis of rings, the early forms of the parasite. Plasma-compatible antimalarial EPI concentrations did not inhibit G6PD activity and did not induce ring opsonization by immunoglobulin G and complement fragments, as observed in G6PD deficiency, but nevertheless remarkably stimulated ring phagocytosis. Plasma-compatible, low-micromolar concentrations of EPI induced exposure on the ring surface of phosphatidylserine, a signal for phagocytic removal independent of opsonization. We propose that enhanced ring phagocytosis due to exposure of negatively charged membrane phospholipids may explain the antimalarial activity of EPI.
A Resistance-Nodulation-Cell Division Family Xenobiotic Efflux Pump in an Obligate Anaerobe,
Porphyromonas gingivalis
Authors: Ikeda Takeshi , Yoshimura Fuminobu 
Published: September 2002

ABSTRACT

Porphyromonas gingivalis
, a gram-negative obligate anaerobe, contains two homologs of an
Escherichia coli
resistance-nodulation-cell division-type multidrug exporter gene,
acrB
, in putative operons, together with homologs of membrane fusion protein gene
acrA
and outer membrane channel gene
tolC
. MIC determination and accumulation assays with mutants with disruptions of one or more genes showed that one cluster, named
xepCAB
, pumped out multiple agents including rifampin, puromycin, and ethidium bromide.
A class of hyperrings and hyperfields
Authors: Krasner Marc 
Published: September 2002

Hyperring is a structure generalizing that of a ring, but where the addition is not a composition, but a hypercomposition, i.e., the sum x + y of two elements, x, y, of a hyperring H is, in general, not an element but a subset of H. When the non‐zero elements of a hyperring form a multiplicative group, the hyperring is
called a hyperfield, and this structure generalizes that of a field. A certain class of hyperfields (residual hyperfields of valued fields) has been used by the author [1] as an important technical tool in his theory of approximation of complete valued fields by sequences of such fields. Tne non‐commutative theory of hyperrings (particularly Artinian) has been studied in depth by Stratigopoulos [2].The question arises: How common are hyperrings? We prove in this paper that a
conveniently defined quotient R/G of any ring R by any normal subgroup G of its multiplicative semigroup is always a hyperring which is a hyperfield when R is a field. We ask: Are all hyperrings isomorphic to some subhyperring of a hyperring belonging to the class just described?
Isomorphisms of semigroups of transformations
Authors: Murti A. Sita Rama 
Published: September 2002

If M is a centered operand over a semigroup S, the suboperands of M containing zero are characterized in terms of S‐homomorphisms of M. Some properties of centered operands over a semigroup with zero are studied.A Δ‐centralizer C of a set M and the semigroup S(C, Δ) of transformations of M over C are introduced, where Δ is a subset of M. When Δ = M, M is a faithful and irreducible centered operand over S(C, Δ). Theorems concerning the isomorphisms of semigroups of transformations of sets Mi over Δi‐centralizers Ci, i = 1, 2 are obtained, and the following theorem in ring theory is deduced: Let Li, i = 1, 2 be the rings of linear transformations of vector spaces (Mi, Di) not necessarily finite dimensional. Then f is an isomorphism of L1 → L2 if and only if there exists a 1 − 1 semilinear transformation h of M1 onto M2 such that fT = hTh−1 for all T ∈ L1.
On locally conformal Kähler space forms
Authors: Matsumoto Koji 
Published: September 2002

An m‐dimensional locally conformal Kähler manifold (l.c.K‐manifold) is characterized as a Hermitian manifold admitting a global closed l‐form αλ (called the Lee form) whose structure satisfies

urn:x-wiley:01611712:media:ijmm569581:ijmm569581-math-0002

,
where ∇λ denotes the covariant differentiation with respect to the Hermitian metric gμλ, , and the indices ν, μ, …, λ run over the range 1, 2, …, m.For l. c. K‐manifolds, I. Vaisman [4] gave a typical example and T. Kashiwada ([1],
[2],[3]) gave a lot of interesting properties about such manifolds.In this paper, we shall study certain properties of l. c. K‐space forms. In §2, we shall mainly get the necessary and sufficient condition that an l. c. K‐space form is an Einstein one and the Riemannian curvature tensor with respect to gμλ will be expressed without the tensor field Pμλ. In §3, we shall get the necessary and sufficient condition that the length of the Lee form is constant and the sufficient condition that a compact l. c. K‐space form becomes a complex space form. In the last §4, we shall prove that there does not exist a non‐trivial recurrent l. c. K‐space form.
On center‐like elements in rings
Authors: Fisher Joe W. , Fahmy Mohamed H. 
Published: September 2002

In a paper with a similar title Herstein has considered the structure of prime rings which contain an element a which satisfies either [a, x] n = 0 or is in the center of R for each x in R. We consider the structure of rings which contain an element a which satisfies powers of certain higher commutators. The two types which we consider are (1) or is in the center of R for all x1, x2, …, xm in R and (2) for all x1, x2, …, xm in R. We obtain results similar to those obtained by Herstein; however, in some cases we must strengthen the hypotheses.Also we consider a third type (3) for all x in R and extend results of Herstein and Giambruno.
Diophantine equations and identities
Authors: Baica Malvina 
Published: September 2002

The general diophantine equations of the second and third degree are far from being totally solved. The equations considered in this paper are

urn:x-wiley:01611712:media:ijmm317827:ijmm317827-math-0001

Infinitely many solutions of each of these equations will be stated explicitly, using the results from the ACF discussed before.It is known that the solutions of Pell′s equation are well exploited. We include it here because we shall use a common method to solve these three above mentioned equations and the method becomes very simple in Pell′s equations case.Some new third and fifth degree combinatorial identities are derived from units in algebraic number fields.
A note on maximally resolvable spaces
Authors: Tzannes V. 
Published: September 2002

A.G. El′kin [1] poses the question as to whether any uncountable cardinal number can be the dispersion character of a Hausdorff maximally resolvable space.In this note we prove that every cardinal number ℵ ≥ ℵ1 can be the dispersion character of a metric (hence, maximally resolvable) connected, locally connected space. We also proved that every cardinal number ℵ ≥ ℵ0 can be the dispersion character of a Hausdorff (resp. Urysohn, almost regular) maximally resolvable space X with the following properties: 1) Every continuous real‐valued function of X is constant, 2) For every point x of X, every open neighborhood U of x, contains an open neighborhood V of x such that every continuous real‐valued function of V is constant. Hence the space X is connected and locally connected and therefore there exists a countable connected locally connected Hausdorff (resp. Urysohn or almost regular) maximally resolvable space (not satisfying the first axiom of countability).
Notes on sufficient conditions for a graph to be Hamiltonian
Authors: Paul Michael Joseph , Shershin Carmen Baytan , Shershin Anthony Connors 
Published: September 2002

The first part of this paper deals with an extension of Dirac′s Theorem to
directed graphs. It is related to a result often referred to as the Ghouila‐Houri
Theorem. Here we show that the requirement of being strongly connected in the hypothesis
of the Ghouila‐Houri Theorem is redundant.The Second part of the paper shows that a condition on the number of edges for a
graph to be hamiltonian implies Ore′s condition on the degrees of the vertices.
Chain Conditions on Semirings
Authors: Mukherjee T. K. , Sen M. K. , Ghosh Shamik 
Published: September 2002

In this paper we characterize the class of semirings S for which the semirings of
square matrices Mn(S) over S are (left) k‐artinian. Also an analogue of the Hilbert basis theorem for
semirings is obtained.Corrigendum to “Chain conditions on semirings”dx.doi.org/10.1155/S0161171297000550
Lattice separation, coseparation and regular measures
Authors: Figueres Maurice C. 
Published: September 2002

Let X be an arbitrary non‐empty set, and let ℒ, ℒ1, ℒ2
be lattices of subsets of X
containing
ϕ and X. 𝒜(ℒ) designates the algebra generated by ℒ and M(ℒ), these finite, non‐trivial,
non‐negative finitely additive measures on 𝒜(ℒ). I(ℒ) denotes those elements of M(ℒ) which assume
only the values zero and one. In terms of a μ ∈ M(ℒ) or I(ℒ), various outer measures are introduced.
Their properties are investigated. The interplay of
measurability, smoothness of μ, regularity of μ and
lattice topological properties on these outer measures is also investigated.Finally, applications of these outer measures to separation type
properties between pairs of
lattices ℒ1, ℒ2 where ℒ1 ⊂ ℒ2 are developed. In
terms of measures from I(ℒ), necessary and sufficient
conditions are established for ℒ1 to semi‐separate ℒ2, for ℒ1 to separate ℒ2, and finally for ℒ1 to coseparate ℒ2.
s‐point finite refinable spaces
Authors: Davis Sheldon W. , Grabner Elise M. , Grabner Gray C. 
Published: September 2002

A space X is called s‐point finite refinable (ds‐point finite refinable) provided every open cover 𝒰 of X has an open refinement 𝒱 such that, for some (closed discrete) C⫅X,(i) for all nonempty V ∈ 𝒱, V∩C ≠ ∅ and(ii) for all a ∈ C the set (𝒱)a = {V ∈ 𝒱 : a ∈ V} is finite.In this paper we distinguish these spaces, study their basic
properties and raise several interesting questions. If λ is an ordinal with cf(λ) = λ > ω and S is a stationary subset of λ then S is not s‐point finite refinable. Countably compact ds‐point finite refinable spaces are compact. A space X is irreducible of order ω if and only if it is ds‐point finite refinable. If X is a strongly collectionwise Hausdorff ds‐point finite refinable space without isolated points then X is irreducible.
Improving homework compliance in the treatment of generalized anxiety disorder
Authors: Leahy Robert L. 
Published: September 2002

AbstractGeneralized anxiety disorder is a chronic condition characterized by beliefs that worry prepares and protects, but that excessive worry is out of control. In this article, I review the cognitive‐behavioral model of generalized anxiety, focusing specifically on problems related to excessive worrying. Noncompliance in self‐help homework is reflected in the patient's excessive focus on negative feelings, difficulty identifying automatic thoughts, demand for immediate results, and the belief that worries are realistic. Interventions for these problems are illustrated in the case of the treatment of a patient characterized by persistent worries, low self‐confidence, procrastination, and avoidance. © 2002 Wiley Periodicals, Inc. J Clin Psychol/In Session 58: 499–511, 2002.
A study on observed evolution of boundary layer humidity distributions
Authors: Price Jeremy D. 
Published: September 2002

AbstractData are used from the Met Office tethered balloon facility to examine the evolution of boundary layer humidity probability density functions during various meteorological conditions. Results typically show significant changes in all four moments (mean, standard deviation, skewness and kurtosis) over periods from one to several hours. Boundary layers experiencing the greatest changes were normally convective in nature. In contrast, a quiescent wintertime boundary layer was seen to show very little evolution over a period of two days. Models which use statistical distributions of humidity for cloud prediction should ideally be able to reproduce these observations. Copyright © 2002 British Crown Copyright.
Biogeophysical impacts of land use on present‐day climate: near‐surface temperature change and radiative forcing
Authors: Betts Richard A. 
Published: September 2002

AbstractChanges in land cover affect climate through the surface energy and moisture budgets, but these biogeophysical impacts of land use have not yet been included in General Circulation Model (GCM) simulations of 20th century climate change. Here, the importance of these effects was assessed by comparing climate simulations performed with current and potential natural vegetation. The northern mid‐latitude agricultural regions were simulated to be approximately 1–2 K cooler in winter and spring in comparison with their previously forested state, due to deforestation increasing the surface albedo by approximately 0.1 during periods of snow cover. Some other regions such as the Sahel and India experienced a small warming due to land use. Although the annual mean global temperature is only 0.02 K lower in the simulation with present‐day land use, the more local temperature changes in some regions are of a similar magnitude to those observed since 1860. The global mean radiative forcing by anthropogenic surface albedo change relative to the natural state is simulated to be −0.2 Wm2, which is comparable with the estimated forcings relative to pre‐industrial times by changes in stratospheric and tropospheric ozone, N2O, halocarbons, and the direct effect of anthropogenic aerosols. Since over half of global deforestation has occurred since 1860, simulations of climate since that date should include the biogeophysical effects of land use. Copyright © 2001 British Crown Copyright.
The effect of insulin on proteins associated with free, cytoskeletal‐bound and membrane‐bound polysome populations.
Authors: Moss Rigmor , Pryme Ian F. , Vedeler Anni 
Published: September 2002

AbstractIt is known that insulin treatment increases the rate of protein synthesis in many cells and tissues and that it causes changes in the distribution of ribosomes between free (FP), cytoskeletal‐bound (CBP) and membrane‐bound polysome (MBP) populations. This paper concerns an analysis of the pattern of proteins in high‐salt extracts of FP, CBP and MBP isolated from Krebs II ascites and MPC‐11 cells. A combined detergent/salt extraction procedure was used to isolate the three fractions of polysomes from control cells and from cells following short‐term stimulation with insulin. There were differences in the protein patterns in the individual fractions and changes occurred after insulin stimulation.
Carbohydrate metabolism of lung tissue of suckling and adult rats.
Authors: Maritz G. S. 
Published: September 2002

AbstractThe carbohydrate metabolism of lung tissue of suckling (1‐3 weeks) and adult (40‐42 weeks) rats were investigated and compared. The results showed that the apparent km for in vitro glucose utilization was 3,13 mM for adult lung and the V max 136,99 μmol/g/h. This could not be determined for neonatal animals. The rate of glucose entry into the glycolytic pathway of adult lung was faster than in the lung of neonatal rats. However, glycogen utilization by neonatal lung was faster than by adult lung. The in vitro oxygen consumption of the lung tissue slices of both age groups were the same. It is proposed that the slower rate of glucose entry into glycolysis in lung tissue of suckling rats is due to a different hexokinase isoenzyme profile. It is also concluded that glycogen‐glucose plays a major role in lung development.
The role of growth factors in gastrointestinal cell proliferation.
Authors: Alison Malcolm R. , Sarraf Catherine E. 
Published: September 2002

AbstractThe epithelial lining of the gastrointestinal (GI) tract is in a state of continuous cell renewal, and the proliferating and differentiating/differentiated cell populations are spatially clearly demarcated. Members of the epidermal growth factor (EGF) family of peptides, the trefoil peptides and enteroglucagon appear to be the most important enterotrophic molecules for both normal cell renewal and healing after cell damage. Transforming growth factor‐a (TGF‐a) appears to be the primary physiological ligand for the EGF receptor (EGFR), promoting normal cell renewal, and TGF‐a/EGFR are part of an autocrine loop in many intestinal cancers. In response to damage, a differentiating cell lineage arises from adjacent epithelium secreting EGF, TGF‐a and trefoil peptides; this may be viewed as part of a ‘repair kit’ in damaged endodermally‐derived tissue.
A 170 kDa polypeptide from mung bean shares multiple epitopes with rabbit skeletal myosin and binds ADP‐adpagarose
Authors: Qiao Lin , Jablonsky Peter P. , Elliott Janet , Williamson Richard E. 
Published: September 2002

ABSTRACTA 170 kDa polypeptide that has been partially purified from mung beans is retained by ADPagarose even in the absence of divalent cations when most non‐myosin ATPases and kinases do not bind. Attempts to demonstrate a myosin‐like ATPase activity were inconclusive, however, and the protein accounts at most for only a small part of the total K+ EDTA ATPase activity of mung bean extracts. All four monoclonal antibodies raised to the 170 kDa polypeptide react with rabbit skeletal muscle myosin and localize the 170 kDa polypeptide in mung bean root tip cells to the actin‐containing phragmoplast and to sites dispersed throughout the cytoplasm which probably include some but not all actin cables. These 4 monoclonals and 3 commercially available antimyosin monoclonals all recognise rabbit skeletal myosin and 160‐170 kDa proteins that are present in two other angiosperms tested. In addition, a 158 kDa protein of mung bean reacts with only one antibody and does not bind ADP‐agarose. We conclude that strong but not yet conclusive evidence points to the 160‐170 kDa proteins of angiosperms being a widely conserved form of myosin heavy chain.
Gelatinases and metalloproteinase inhibitor secreted by murine colonic carcinoma cells with differing metastatic potential
Authors: Kishi Jun‐Ichi , Tanaka Rie , Koiwai Osamu , Yamagata Sadako , Numata Yukiko , Hayakawa Taro , Shimizu Satoru 
Published: September 2002

ABSTRACTGelatinase activity and inhibitory activity against collagenase were measured in serum‐free medium conditioned by murine colonic carcinoma cells with different spontaneous metastatic potentials to the lung. The medium conditioned with poorly metastatic NM11 cells gave higher inhibitory activity than that conditioned with highly metastatic LuM1 cells, while the level of secreted gelatinases in the same medium was lower in NM11 medium than in LuM1 case. Northern analysis showed the higher gene expression of both tissue inhibitor of metalloproteinases (TIMP)‐1 and TIMP‐2 in NM11 cells than in LuM1 cells, suggesting that both TIMPs are responsible for the increase of inhibitory activity in NM11 conditioned medium. Examination of the balance of gelatinases and inhibitor revealed that the amount of inhibitor exceeded that of gelatinases in the medium conditioned with NM11 cells. In contrast, the medium conditioned with LuM1 cells contained excess amounts of gelatinases. The results indicated a close correlation between the balance of gelatinases and inhibitors and the metastatic behavior of murine tumor cells.
Calcium‐activated chloride fluxes in cultured NCL‐SG3 sweat gland cells
Authors: Ring Avi , Mörk Ann‐Christin , Roomans Godfried M. 
Published: September 2002

ABSTRACTThe dependence of chloride permeability of the human sweat gland cell line NCL‐SG3 cell line on cytosolic free calcium ([Ca2+]i) was investigated. X‐ray microanalysis, fura‐2 fluorescence and patch clamp methodology were used. Carbachol and A23187 decreased cellular Cl and K for cells grown on permeable supports, but carbachol had no effect on cells grown on impermeable supports. In perforated patch experiments with impermeable supports, ATP and calcium ionophores increased the inward current (ic) whereas carbachol had no effect. ic was unaffected by cation channel blockers or removal of extracellular Na+ but was blocked by chloride channel blockers. Lowering bath Ca2+ decreased ic. On raising bath Ca2+ ic and [Ca2+]i responded with a transient rise which was not blocked by La3+ or D‐600. La3+, but not D‐600, blocked the entry of Mn2+. K+‐depolarization and Bay‐K‐8644 had little effect on [Ca2+]i. The rise in [Ca2+]i may be mediated primarily via depletion operated Ca2+‐channels. Irrespective of substrate NCL‐SG3 cells have a chloride permeability which depends on [Ca2+]i.
The epidermal growth factor.
Authors: Boonstra Johannes , Rijken Philip , Humbel Bruno , Cremers Fons , Verkleij Arie , en Henegouwen Paul van Bergen 
Published: September 2002

ABSTRACTEpidermal growth factor (EGF) is a single polypeptide of 53 amino acid residues which is involved in the regulation of cell proliferation. Egf exerts its effects in the target cells by binding to the plasma membrane located EGF receptor. The EGF receptor is a transmembrane protein tyrosine kinase. Binding of EGF to the receptor causes activation of the kinase and subsequently receptor autophosphorylation. The autophosphorylation is essential for the interaction of the receptor with its substrates. These bind to the receptor by the so‐called SH2 domains.The signal transduction pathways activated by EGF include the phosphatidylinositol pathway, leading to activation of protein kinase C and to increase in the intracellular Ca2+ concentration, and to the ras pathway leading to MAP kinase activation.Recently the cytoplasm has been implicated as playing an important role in EGF induced signal transduction. The EGF receptor has been demonstrated to be an actin‐binding protein. In addition EGF causes a rapid actin depolymerisation and the formation of membrane ruffles. In particular these membrane ruffles have been shown to act as the first site of signal transduction after EGF binding, and thus may be considered as signal transduction structures. Finally evidence has been presented suggesting a positive role for EGF and/or the receptor in the nucleus.
Regulation of fibronectin expression by PDGF‐BB And IGF‐I in cultured rat thoracic aortic adventitial fibroblasts.
Authors: Zhang Jing , Lo Chu‐shek 
Published: September 2002

AbstractRegulation of fibronectin (FN) by Platelet‐derived Growth Factor‐BB (PDGF‐BB) and Insulin‐like Growth Factor‐I (IGF‐I) in cultured rat thoracic aortic adventitial fibroblasts were examined. PDGF‐BB enhances FN mRNA levels in a time and concentration‐dependent fashion. The effect of IGF‐I on PDGF‐BB‐induced FN levels was also examined. There was a larger increase in FN mRNA levels (4‐fold) in the cells treated with both IGF‐I and PDGF‐BB than with either IGF‐I (2‐fold) or PDGF‐BB (2‐fold) alone. The effects of PDGF‐BB and IGF‐I on FN levels were examined. There was a larger increase in FN levels (135%) in the cells treated with both PDGF‐BB and IGF‐I than with either PDGF‐BB (43%) or IGF‐I (45%) alone. Regulation of adventitial fibroblast FN may lead to blood vessel diseases and/or angiogenesis.