bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient distributed algorithm to solve updating minimum spanning tree problem
Authors: Park Jungho , Hagihara Ken'Ichi , Tokura Nobuki , Masuzawa Toshimitsu
Published: July 2007

This paper proposes a distributed algorithm for reconstructing a minimum‐weight spanning tree T′ of a network N′ when link addition and deletion occur in a network N with a minimum‐weight spanning tree T. In this algorithm each processor uses information whose adjacent links belong to T in order to construct T′ efficiently. The communication complexity and ideal time complexity of the algorithm are O(n log(f + t) + m) and O(n log(f + t) + n), respectively, where n and e are the number of processors and that of links in N′, t is the number of added links, and f represents that of deleted links belonging to T. Here, m = n + t when f = 0 and m = e otherwise.

This paper also presents a distributed algorithm for reconstructing a minimum‐weight spanning tree T+ when links and processors are added and deleted. The communication complexity and ideal time complexity of the algorithm are O(n log(g + h) + r and O(n log(g + h) + n), respectively, where g is the total number of added links (including links incident to added processors) and h represents the number of deleted links belonging to T (including links incident to deleted processors). Thus, r = n + g when h = 0 and r = e when h > 0.
RMD‐tree: A hierarchical data structure for multidimensional nonzero size spatial objects using MD‐tree
Authors: Nakamura Yasuaki , Abe Shigeru , Ohsawa Yutaka , Sakauchi Masao
Published: July 2007

This paper proposes an RMD‐tree (region multidimensional tree), which is a method of data management based on the tree structure, aiming at the efficient management and retrieval of spatial objects with nonzero sizes.

In the proposed method, the spatial object in the N‐dimensional space corresponds to a point in the 2N‐dimensional space, being represented by its centroid and the extent along each axis. The coordinate transformation is applied to the point data and the data are managed by the tree structure, so that retrieval such as the point location problem or the range search in the n‐dimensional space can be performed only by the search for the point data in the hyper‐rectangle range.

By this approach, the space splitting and data management are made possible considering the size of the object as well as the centroid. By the coordinate transformation the object data are represented by the maximum and the minimum in the original N‐dimensional space, multiplied by a certain factor.

It is indicated by simulation experiments that the speed of search is improved by this method by a factor of 2 to 4, compared to the conventional method when the size of the object to be managed is enlarged. When points and objects with small sizes are to be handled, the performance is almost the same as that of the conventional method. In the experiment using the actual printed circuit board data, the speed of search also is improved by approximately a factor of 2.
Distributed algorithms for connectivity problem of networks with faulty elements
Authors: Wada Koichi , Moritani Yukio , Kawaguchi Kimio , Morishita Masahiro
Published: July 2007

Distributed algorithms for computing the connectivity of an asynchronous computer network with faulty computers and links are investigated. Computers which are adjacent to faulty computers and links are assumed to be capable of detecting the faults. The existence and efficiency of distributed algorithms depend on the kinds of information each computer is allowed to have on the network before executing an algorithm.

Here, the case in which computers fail and the case in which only links fail are considered separately. It is shown that in the former case there is no algorithm for computing the connectivity regardless of the kind of information a computer has about the network. In the latter case the existence of a distributed algorithm, upper and lower bounds of communication complexity and ideal time complexity are discussed for the following three cases: each computer has only the basic information (its identifier and the number of links connected to it); each computer has the basic information and the identifier of the adjacent computers; and each computer has the basic information and the size of the network.
Implementation of the prodigy parallel AI machine and performance evaluation of communication
Authors: Tanabe Noboru , Nakamura Sadao , Suzuoka Takashi , Oyanagi Shigeru
Published: July 2007

At present, the binary n‐cube is considered to be interesting as an interconnection network for the highly parallel computers. Most of those networks, however, use the serial communication channel, which prevents the realization of satisfactory communication performance. From such a viewpoint, it is desired to construct an interconnection network with higher speed, higher versatility, and the easy implementation.

The authors have already proposed the base‐m n‐cube as the interconnection network for the parallel AI machine Prodigy. This paper shows that the base‐m n‐cube is better than the binary n‐cube in versatility and easy implementation. Furthermore, the authors developed Prodigy which utilizes the forementioned excellent property to connect 512 processors by the 8‐bit width full duplex base‐8 3‐cube with a handshake. Two kinds of gate arrays are used in the implementation. It is shown as a result that the interconnection network can be constructed with the highest speed in the presently known cube‐type highly parallel computers. It is verified by an actual measurement that the transfer performance is deteriorated only slightly by the collision in the random communication.
Component‐based protocol synthesis
Authors: Kakuda Yoshiaki , Wakahara Yasushi , Saito Hironori
Published: July 2007

Protocol synthesis is a very important technology for efficiently designing correct protocol specifications. One powerful means of protocol synthesis is the completion of protocol specifications which, based on a partial specification of functionally incomplete protocol, automatically generates the insufficient part. In contrast to such protocol synthesis, this paper proposes a method for completing protocol specifications with two processes by modeling the protocol by a finite‐state machine and combining fundamental components of correct protocol.

Compared to conventional method, the protocol synthesis method proposed in this paper has the following merits: (1)protocols containing looping receive‐transition sequences can be generated; and (2)redundant send‐transition sequences can be eliminated. Because of these merits, it is possible to synthesize protocols used in actual communication systems, for example, the X.25 call setup/clearing protocol.
A scan conversion algorithm using quad‐tree representation of dZ buffer
Authors: Yamamoto Tsuyoshi
Published: July 2007

This paper proposes an extension of the Z buffer or dZ buffer that stores not only the Z component but also the normal vector of a visible polygon at the sampling point. While the conventional Z buffer algorithm is based on a zeroth‐order approximation of a visible polygon, the dZ buffer is considered as a first‐order approximation. As a result, the dZ buffer can approximate a surface by fewer sampling points.

A quad‐tree based internal representation of the dZ buffer and scan conversion algorithm has been proposed using the representation. The proposed algorithm uses memory in proportion to the complexity of the generated image while the Z buffer uses memory in proportion to the image size. While the algorithm allows an incremental update of the dZ buffer as similarly to the Z buffer, anti‐alias processing is possible by controlling oversampling on demand.

The algorithm can be implemented using recursive procedure calls including simple overlapping detection of triangles and rectangles. The algorithm is implemented and evaluated on a UNIX workstation and the result shows better figures in both conversion time and memory requirement.
Ellipsometric study of the poling effect on nonlinear-optical side-chain polymers containing disperse red 1
Authors: Lee Ho Suk , Kang Tae Dong , Lee Hosun , Lee Sang Kyu , Kim Ju Hee , Choi Dong Hoon
Published: July 2007

The purpose of this work is to investigate the effect of corona poling on the optical functions of the nonlinear-optical (NLO) polymers. We measured the complex refractive indices of NLO polymers deposited on glasses before and after corona poling using spectroscopic ellipsometry at room temperature at various incidence angles. In addition, we observed the absorption spectral change using ultraviolet-visible spectroscopy after corona poling, which is attributed to the chromophore orientation. In order to make NLO polymers, we attached a NLO active dye and photocrosslinkable moieties as side chains of poly(4-hydroxystyrene), deposited the polymer thin films on glass substrates by spin-coating, and corona-poled it along the surface-normal direction to align the dipoles of the chromophores along the electric field direction. In detail, PSDR1-25 designates a poly(4-hydroxystyrene) where 25% of hydroxyl groups in the side chain are substituted by disperse red 1 (DR1) and PSDR1-50 means the same except for 50% substitution. PSDR1 has the second-order NLO property, which is expected to show an acentric ordering by poling electric field. We used a parametric optical constant model to estimate the complex refractive index of the polymers. We found that the poling induced the uniaxial property of the complex refractive index of the polymers by aligning the chromophores along the poling direction. With increased poling voltage, we found that the oscillator strength of the major peak near the 2.4eV (designated as Ea) peak decreases in the surface-parallel direction (x), whereas that of the surface-normal direction (z) increases. Moreover, a detailed analysis of the dielectric functions using the standard critical point model showed that the poling induced a new peak Ec (∼2.6eV) between dominant Ea (∼2.3eV) and weak Eb (∼2.9eV) peaks for PSDR1-50 polymers. With increased poling voltage, the Ec peak strength increased compared to those of Ea and Eb peaks. We tentatively attribute Ec to lower symmetry, possibly Stark effect, induced in the chromophores by the corona poling.
Effect of Pb on the low frequency Raman modes in Bi2−xPbxSr2CaCu2O8+δ and Bi2−xPbxSr2Ca2Cu3O10+δ superconductors
Authors: Williams G. V. M.
Published: July 2007

Low frequency Raman spectroscopy measurements have been made on Bi2−xPbxSr2CaCu2O8+δ and Bi2−xPbxSr2Ca2Cu3O10+δ high temperature superconductors. The frequency of the ∼118cm−1 peak is found to correlate with the Pb content, and there is no correlation with the hole concentration in the CuO2 planes when it is varied by changing the oxygen content in the BiO layers. Thus, Raman measurements provide a means by which the Pb content can be estimated. When used in conjunction with measurements of the frequency of the O(2)SrA1g Raman mode, it is possible to also estimate the hole concentration in the CuO2 plane.
The origins and development of social psychology in Canada
Authors: Adair John G.
Published: July 2007

This article provides an overview of the historical events, significant personalities, and contextual influences that have shaped the development of social psychology in Canada. For much of its history, Canada and its closest neighbour, the US, have shared similar social problems and, for a time, even research funding. Although the influence of the US has been imprinted on Canadian research and theory, Canadian social psychology has also developed its own discipline with a focus on culture and explicitly Canadian social issues that makes it distinct from that of the US. This account reveals how Canadian social psychology developed and where US influence has been felt. Emerging from its roots within philosophy, Canadian psychology began as a decidedly applied discipline; but following its widely acknowledged contributions to the Canadian war effort it was basic research that ultimately received the academic appointments and financial support. Social psychology was often invisible; to be found, if at all, only on the fringe of both these early developments. In the 1970s, the Canadian government's decision to fund social research, and a period of exceptional growth of higher education, contributed to the discipline's emergence. Substantial numbers of experimental social psychologists imported from the United States raised questions about the Canadian content of their teaching and research, but their perspective and numbers created the critical mass needed for advancement of our discipline. With the help of a partly government‐imposed Canadianization of academia and a blending of these imported researchers with the culture‐oriented researchers trained in Canada, social psychology evolved into the mature, distinctive discipline that exists in Canada today. Canada has a strong, self‐sustaining national disicpline, that in accord with its size makes substantial contributions to the world of psychology and to the social psychology of North America. This developmental history describes how these accomplishments have been realized.
The Emergence of the Kosovo “Parallel State,” 1988–19921
Authors: Pula Besnik
Published: July 2007

This article examines the origins of the nonviolent resistance movement in Kosovo in the early 1990s, with the purpose of explaining the dynamics that led to the emergence of the so-called “parallel state” of Kosovo Albanians.
EFFECTIVENESS OF RESTRICTIONS ON AVAILABILITY AS A MEANS OF REDUCING THE USE AND ABUSE OF ALCOHOL#
Authors: Smith D.I.
Published: July 2007

The effect of changes in the legal minimum drinking age, hours of sale of alcoholic beverages and number and type of liquor outlets on variables for the use and abuse of alcohol are reviewed. Implications for research and preventive education of the conclusions drawn are briefly discussed.
A SYSTEMS APPROACH TO THE MANAGEMENT OF DRUG‐RELATED PROBLEMS
Authors: REILLY D.K. , HEGG J. , TWYMAN D.
Published: July 2007

A comprehensive assessment of an individual's drug problem needs to include consideration of the type, frequency and amount of drug use, degree of dependence, concomitant medical problems and general health, previous treatment history, family and social relationships, employment and financial situation, psychological functioning, criminal activity and legal situation. The aim of a community based drug advisory service in Sydney is to provide an assessment‐referral‐treatment service which aims to match an individual's drug‐related problems to the most appropriate range of therapeutic interventions. The components of the system include: intake, assessment, case conference, intervention and research. The system also accommodates the NSW Drug and Alcohol Court Assessment Program which interfaces Criminal Justice and Health Systems. Clinical programs of the service are described including a methadone maintenance program.
Training in Drug and Alcohol Problems for Family Medicine
Authors: Fraillon J.M.G.
Published: July 2007

Abstract: The elective terms and courses offered by the Victoria Faculty of the Royal Australian College of General Practitioners are described.
The Reliability of Dietary Assessment in Problem Drinkers with Indications of Cross‐National Differences
Authors: Price John , Hoon Robert Ah , Williams Gail
Published: July 2007

Abstract: The aim of this study was to determine the reliability of statements that problem drinkers make about their diets, including the degree of agreement with information from collateral sources. Twenty problem drinkers with intact memories were questioned about dietary intake in the six weeks prior to admission to alcohol rehabilitation units in both Queensland and the U.K. Similar information was obtained independently from relatives or friends with whom these drinkers resided during this period. Data collected related to food items, amounts consumed, meals missed, physiological changes, attitudes and responses to dietary neglect and pressure to eat more. Two researchers rated 24 of these interviews independently and achieved excellent inter‐rater reliability. Overall, good agreement between the information supplied by the drinker and that from the informant was found for food items, meals consumed and supplementary vitamin intake. Where there was discrepancy, the higher estimates of food item and meal consumption usually came from the informant in Queensland but from the drinker in the U.K. Informants applied pressure to eat significantly more often in the U.K. than in Queensland, and had greater knowledge of physiological changes. It is hypothesized that Queensland informants are more optimistic but less involved with the drinker than their U.K. counterparts.
Lessons from a controlled evaluation of a general practice minimal intervention for problem drinking
Authors: Heather Nick
Published: July 2007

Abstract: A controlled evaluation of the Scottish Health Education Group's DRAMS Scheme in general practice failed to provide good evidence of the effectiveness of DRAMS compared with advice‐only and non‐intervention control groups, but also failed to provide an adequate test of DRAMS. Reasons for this are discussed and three kinds of lessons are drawn from the experience: lessons for future research into GP minimal interventions; lessons for the design of the interventions themselves; and, finally, lessons for strategies to be employed in the effort to engage the full interest and co‐operation of general practitioners in working with problem drinkers.
Glucocorticoids Inhibit the Cerebral Microvascular Dysfunction Associated with Sepsis in Obese Mice
Authors: VACHHARAJANI VIDULA , VITAL SHANTEL , RUSSELL JANICE , SCOTT L. Keith , GRANGER D. Neil
Published: July 2007

Objectives: Obesity is associated with increased morbidity and mortality in critically ill patients. It is unclear whether this increase is due to exaggerated inflammatory response alone or due to lack of response to therapeutic agents used. The objective of this study was to determine whether low‐dose steroid therapy, which has proven effective in clinical setting, affords any benefit in the increased morbidity to sepsis in genetically obese (ob/ob) mice.

Methods: Intravital videomicroscopy was used to monitor and quantify the adhesion of platelets and leukocytes in the brain microcirculation of lean (WT) and ob/ob mice subjected to cecal ligation and puncture (CLP) with or without dexamethasone 4 mg/kg within 15 min of surgery. The dual radiolabeled monoclonal antibody method was used to measure P‐selectin expression in the microcirculation, while the sepsis‐induced behavioral deficit was quantified using a multicompartment chamber test.

Results: Dexamethasone completely prevented the accumulation of adherent leukocytes and platelets observed at 4 h after CLP in both WT and ob/ob mice. The steroid also prevented the CLP‐induced upregulation of P‐selectin in the brain and other vascular beds, and it attenuated the behavioral deficit in ob/ob, but not in lean, mice.

Conclusion: Low‐dose glucocorticoid therapy is beneficial in experimental sepsis in obese animals compared to lean animals.
Vitamin E protects the brain against oxidative injury stimulated by excessive aluminum intake
Authors: El‐Fattah Amal A. Abd , Al‐Yousef Hanan M. , Al‐Bekairi Abdullah M. , Al‐Sawaf Hussein A.
Published: July 2007

The effect of feeding groups of mice with a diet containing 2000, 4000 and 6000 μg aluminum (Al3+/g) for two weeks (subacute) or 2000 and 4000 μg Al3+/g for eight weeks (subchronic) as well as the coadministration of vitamin E (α‐tocopherol) 500 μg/g with Al3+, on the status of glutathione (GSH) and lipid peroxides as thiobarbituric acid reactive substances (TBARS) in whole brain tissues were evaluated. Changes in TBARS were further evaluated in vitro following the incubation of brain homogenates of the Al3+‐fed mice in the presence of 50 μM FeSO4. The results of subacute experiments revealed that the brain levels of GSH were significantly decreased only in the group of mice that received 6000 μg Al3+/g diet (P<0.05) and this effect was partially ameliorated when vitamin E was coadministered with Al3+. TBARS were significantly increased in vitro only in the presence of free iron ions and depended on the concentration of Al3+ in the diet. The effect was opposed by the vitamin E intake.

Following subchronic Al3+ intake, the GSH content of the brain was significantly decreased only in the group of mice that received 4000 μg Al3+/g diet (P<0.01), while TBARS were significantly increased in the brain tissues in vivo as well as in the presence of free iron ions in vitro. However, coadminstration of vitamin E with Al3+ for eight weeks preserved GSH levels and decreased TBARS in the brain of mice in vivo and in the presence of free iron ions in vitro. It is concluded that the long term administration of vitamin E may prevent Al3+‐stimulated oxidative injury in the brain.
CYP2B2 gene expression and phenobarbital induction in kidneys using an in vitro transcription system
Authors: Shervington Amal
Published: July 2007

The induction of cytochrome P450 2B1 and 2B2 in rat liver in response to phenobarbital is mediated at the transcriptional level. While in extrahepatic tissue such as the kidney, the transcription level of the CYP 2B2 gene is much lower than in the liver. The transcriptional activity of the CYP2B2 promoter constructs in nuclear proteins from kidney revealed that the in vitro system maintained the tissue‐specificity of CYP2B2 transcriptional induction but not that of the basal transcription of the gene.
Purification of cytochrome P‐450 from pig testis by aniline‐sepharose 4B and isoelectric focusing
Authors: Kuwada Masahiro , Furuse Yuko , Hasumi Hideo , Maki Jun
Published: July 2007

Testicular cytochrome P‐450 was purified by a procedure including preparative isoelectrofocusing. The cytochrome P‐450 was detemained to have an isoelectric point of 6.47 on analytical isoelecfric focusing. The purified cytochrome P‐450 was found to be homogeneous and its molecular weight was estimated to be 52000 on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. The carbon monoxide difference spectrum with a peak at 448 nm exhibited absorption spectrum of a typical cytochrome P‐450. 284‐fold purification was achieved with an yield of 10.6 %. Following preparation of the microsomes, the purification is accomplished by a two‐step procedure utilizing Aniline‐Sepharose 4B column chromatography and preparative isoelectric focusing.
Lysosomal glycerophosphocholine phosphodiesterase in Tetrahymena
Authors: Florin‐Christensen J. , Florin‐Christensen M.
Published: July 2007

The purification and characterization of a novel phosphodiesterase (PDE) is presented. The activity was detected in the extracellular medium of Tetrahymena thermophila cultures, by the release of p‐nitrophenol from p‐nitrophenylphosphocholine (PNPPC) with an acidic pH optimum: In cell homogenates, it is sedimentable, shows a latency similar to that of acid phosphatase and is co‐secreted with this enzyme, indicating that it is a lysosomal hydrolase. PNPPC‐PDE was purified to homogeneity from the extracellular medium, yielding a single band of 58 kD on SDS polyacrylamide gel electrophoresis. It catalyzed the release of glycerol from glycerophosphocholine (GPC) and GPC competitively inhibits degradation of PNPPC. We present further evidence indicating that the natural substrate for PNPPC‐PDE is GPC. Thus, Tetrahymena becomes the first eukaryote in which a lysosomal GPC‐PDE is observed. This finding provides a new pathway for the complete breakdown of phosphatidylcholine in a lysosomal medium.
Analysis of photocontrol of aspartate kinase in barley (Hordeum vulgare L.) seedlings
Authors: Rao S. S. , Kochhar S. , Kochhar V. K.
Published: July 2007

Aspartate kinase (AK) activity is regulated by light. The activity was more in light exposed barley seedlings than those grown in the dark. The light effect was manifested even with small exposures of 5 min duration and red light was more effective than white light in this respect. The effect of 5 min red light could be reversed by a 5 min pulse of far‐red light indicating the involvement of phytochrome in this response. The phytochrome is also involved in long term light effects (24 hr exposures with white light). Ca++ takes part in the signal transduction pathway for this light response. Western blot analysis using antibodies raised against the purified lysine‐ and threonine‐sensitive AK isoenzymes from spinach leaves showed no cross reaction with the antibodies to the threonine‐sensitive AK in the dark and 5 min far‐red light exposed seedlings. But the protein band was detected in the white and red lights. Northern blot analysis of seedlings grown under dark and exposed to white, red and far‐red lights and probed with the gene encoding aspartokinase‐homoserine dehydrogenase (AKHSD) protein indicated that the gene was differentially expressed. In dark grown seedlings, AKHSD transcript was in low concentration as compared to white light where the transcript concentration was high. A 5 min red light pulse increased the transcript concentration significantly in contrast to 5 min far‐red light. The transcript concentration was reduced when 5 min red light was followed by a 5 min far‐red light pulse. The AK activity in dark‐raised seedlings is attributed to the presence of only one isoenzyme that is sensitive to lysine but insensitive to Ca++ and calmodulin (CAM). In both white and red light exposed seedlings, three isoenzymes of AK were detected. Two of these were sensitive to threonine while one was sensitive to lysine. Both of the threonine sensitive isoenzymes were activated by Ca++ and CAM. Also one of these isoenzymes seems to be located and synthesized in chloroplasts because its synthesis was completely inhibited by chloramphenicol but not by cycloheximide.
Degradation of an ubiquitin‐conjugated protein is associated with myoblast differentiation in primary cell culture
Authors: Gardrat Florence , Montel Valérie , Raymond Jacques , Azanza Jean‐Louis
Published: July 2007

At the early stages of myogenesis, myoblasts fuse to form multinucleated myotubes. This morphological differentiation is the result of dynamic changes in gene regulation and expression. The ubiquitin proteasome‐dependent pathway has been reported to play an important role in many aspects of cellular functions such as regulation of growth and cell cycle progression. In this study, we showed that the amount of mRNA's corresponding to the iota subunit of the 20S proteasome, the level of the S4 subunit of the 19S complex and the 20S and 26S proteasomes peptidase activities increased during myoblast fusion. Cell permeable 20S proteasome inhibitor prevented fusion with concomitant accumulation of ubiquitin‐conjugated protein. On the other hand, inhibition of ubiquitin ligase E3 enzymes prevented the formation of ubiquitin conjugate and decreased the fusion process. These results strongly support the involvement of the ubiquitin‐proteasome proteolytic pathway in the events leading to myoblast fusion.
Purification and characterization of a novel dipeptidyl peptidase from Dictyostelium discoideum
Authors: Choi Wai S. , Fu Qi , Jones Theodore H. D.
Published: July 2007

A dipeptidyl peptidase (DPP) was purified to homogeneity using lys‐ala‐β‐naphthylamide, the standard substrate for DPP II. The enzyme is a monomer with a Mr of 70kDa, pl 5.2, and Km 5.0μM. Its terminal amino acid sequence was XXLLYAIQKRLF and was not identical to that of any known protein. Although initially considered to be a DPP II, the enzyme differed in some properties from classical DPP IIs. It had a pH optimum of 7.9, was not active on X‐pro‐naphthylamides, the usual substrates of mammalian DPP II, but was active on arg‐arg‐ and asp‐arg‐naphthylamides, substrates acted on by the DPP III class of enzymes. This enzyme therefore combines properties typical of both DPP II and III and differs from all previously described DPPs. Activity on lys‐ala‐β‐naphthylamide was most abundant during aggregation and its activity is consistent with processing specific peptides during development.
A Model of EcoRII Restriction Endonuclease Action: The Active Complex is Most Likely Formed by One Protein Subunit and One DNA Recognition Site
Authors: Karpova Elizaveta A. , Kubareva Elena A. , Shabarova Zoe A.
Published: July 2007

To elucidate the mechanism of interaction of restriction endonuclease Eco RII with DNA, we studied by native gel electrophoresis the binding of this endonuclease to a set of synthetic DNA‐duplexes containing the modified orcanonical recognition sequence 5‐d(CCA/TGG)‐3. All binding substrate or substrate analogues tested could be divided into two major groups: (i) duplexes that, at the interaction with endonuclease EcoRII, form two types of stable complexes on native gel in the absence of Mg+2 cofactor; (ii) duplexes that form only one type of complex, observed both in the presence and absence of Mg+2. Unlike the latter, duplexes under the first group can be hydrolyzed by endonuclease. Data obtained suggest that the active complex is most likely formed by one protein subunit and one DNA recognition sequence. A model of EcoRII endonuclease action is presented.
pp60v‐src Reactivation Inhibits Serum‐Induced Accumulation of Inositol Phosphates and Phosphatidylethanol in tsNRK
Authors: Kim Bo Yeon , Kim Jin Hee , Han Yoon Jeong , Ahn Soon Cheol , Kang Dae Ook , Oh Won Keun , Ko Hack Ryong , Lee Hyun Sun , Mheen Tae Ick , Ahn Jong Seog
Published: July 2007

In tsRSV‐infected NRK (tsNRK) cells, pp60v‐src reactivation by temperature‐shift from a nonpermissive temperature, 39 C, to a permissive one, 32 C, induced the production of inositol phosphates (IPt) and phosphatidylethanol (PEt). This was accompanied by an increase in membrane‐associated protein kinase C (PKC) activity in the absence of exogenous growth factors. However, with serum‐stimulation, the amounts of IPt and PEt at 32 C were less than those at 39 C. Pretreatment with PKC inhibitors, Ro‐31‐8220 and staurosporine, enhanced the accumulation of IPt but not of PEt at 32 C. The tyrosine phosphorylation of phospholipase C gamma1 (PLC gamma1) was increased either by serum or by pp60v‐src reactivation. These results suggest that serum transduces its signal through PLC gamma1 mediation, and that pp60v‐src, possibly through the PKC mediation, negatively affects serum‐induced PLC gamma1 activation.
Macromolecular Mimicry of Nucleic Acid and Protein
Authors: Pedersen Gitte Nautrup , Nyborg Jens , Clark Brian F. C.
Published: July 2007

Although proteins and nucleic acids consist of different chemical components, proteins can mimic structures and possibly also functions of nucleic acids. Recently, structural mimicry was observed between two elongation factors in bacterial protein biosynthesis leading to the introduction of the concept of macromolecular mimicry. Macromolecular mimicry has further been proposed among initiation and release factors, thereby adding a new element to the description of protein synthesis in bacteria. Such mimicry has also been observed in other biological processes such as autoimmunity, DNA repair, and gene regulation, at both transcriptional and translational levels.
The p41 Fragment Story
Authors: Turk Dusan , Guncar Gregor , Turk Vito
Published: July 2007

The discovery of a fragment from the p41 form of invariant chain tightly bound to cathepsin L provided the first direct link between MHC class II molecules and the regulation of activity of lysosomal cysteine proteases. We recently determined the crystal structure of this p41 invariant chain fragment in complex with cathepsin L[EMBO J. 18, 793 803 (1999)]. This structure explains the specificity of the observed interactions and actually provides a tool, which can be utilized by means of molecular biology, to explore and understand the specificity of thyroglobulin type I domains and thus allow the design of specific inhibitors of papain‐like cysteine proteases. The structure further supports the hypothesis that the thyroglobulin type I and II domains present in various proteins, sometimes in multiple repeats, are regulatory elements of the processing of these proteins by proteolytic cleavage.
Use of Novel Bone Biopsy System to Study Molecular Effectst of Growth Hormone in Human Bone‐ A Pilot Study
Authors: Melhus Hakan , Astrom Gunnar , Ahlstrom Hakan , Burman Pia , Karlsson Anders , Ljunghall Sverker
Published: July 2007

In this study, we have examined whether a novel bone biopsy system combined with reverse transcription‐polymerase chain reaction (RT‐PCR) or differential display PCR (ddPCR) can be used to detect specific mRNAs induced by growth hormone (GH) in human bone. In a 58‐year‐old man with complete GH deficiency as a result of empty sella, bone biopsies were taken before, and 5 and 24h after administration of 24 recombinant human GH. Insulin‐like growth factor binding protein‐3 (IGFBP‐3) mRNA levels in this patient, measured in a semiquantitative RT‐PCR assay, increased about 40% 24 h after GH administration. This increase was not seen in a healthy control who did not receive GH, suggesting that the increase was an effect of GH rather than of the biopsy itself. Several differentially expressed mRNAs were detected by ddPCR. Thus, this pilot study suggests that our novel bone biopsy system may be suitable for in vivo studies of the molecular effects of substances with essential functions in human bone.
Phosphorylation‐Dephosphorylation of Retinoblastoma Protein Not Necessary for Passage through the Mammalian Cell Division Cycle
Authors: Cooper Stephen , Yu Chao , Shayman James Alan
Published: July 2007

Phosphorylation of the retinoblastoma protein (Rb) during the G1‐phase of the mammalian cell division cycle is currently believed to be a controlling element regulating the passage of cells into S‐phase. We find, however, that the suspension‐grown cell lines U937, L1210, and MOLT‐4 contain exclusively hyperphosphorylated Rb. Furthermore, when adherent NIH3T3 cells are grown at very low densities to avoid overgrowth and contact inhibition, they also contain only hyperphosphorylated Rb. NIH3T3 cells exhibit hypophosphorylation when the cells are grown at moderate to high cell densities. We propose that cultures of adherent cells such as NIH3T3, when grown to moderate cell densities, are made up of two populations of cells: (a) cells that are relatively isolated and therefore growing exponentially without contact inhibition, and (b) cells that are growth‐inhibited by local cell density or contact inhibition. The common observation in adherent cell lines, that Rb is both hyper‐ and hypophosphorylated in the G1‐phase and only hyperphosphorylated in the S‐ and G2‐phases, is explained by the effects of cell density and contact inhibition. Thus, phosphorylation‐dephosphorylation of Rb protein during the G1 phase is not a necessary process during the NIH3T3, L1210, MOLT‐4, and U937 division cycles. We propose that phosphorylation‐dephosphorylation of Rb is independent of the division cycle and is primarily determined by growth conditions throughout the division cycle.
Caspases in Developmental Cell Death
Authors: Shearwin‐Whyatt Linda M. , Kumar Sharad
Published: July 2007

Caspases are a family of evolutionarily conserved cysteine proteases that constitute the effector arm of the apoptotic machinery. Studies in Caenorhabditis elegans, Drosophila melanogaster, and mouse point to evolutionarily conserved caspase function in developmentally programmed cell death in metazoans. Whereas in the nematode all developmetal cell death is mediated by a single caspase,in Drosophila and the mouse some caspases appear to regulate cell death in a spatio‐temporally restricted manner. This article reviews what we currently know about the roles of various caspases in the execution of developmentally programmed cell death and what may be expected from future research in this field.
Involvement of ArcA and Fnr in Expression of Escherichia coli Thiol Peroxidase Gene
Authors: Kim Sung‐Jin , Han Young‐Hee , Kim Il‐Han , Kim Ha‐Kun
Published: July 2007

To explore the oxygen response regulators involved in thiol peroxidase gene (tpx) expression in Escherichia coli, we constructed a single‐copy tpx‐lacZ operon fusion and monitored tpx‐lacZ expression in various genetic backgrounds. Expression of the tpx‐lacZ fusion was increased 4‐fold by aerobic growth. Anaerobic expression of tpx‐lacZ in either Delta arcA or Delta fnr strains was 2.5‐fold depressed compared with that of the wild‐type strain. The results of immunoblotting experiments also demonstrated that ArcA and Fnr regulatory proteins repressed thiol peroxidase gene expression during anaerobic growth. Inspection of the tpx promoter region revealed putative binding sites for ArcA and Fnr. It thus appears that ArcA and Fnr function as repressors by blocking the binding of RNA polymerase to the tpx promoter in E. coli under anaerobic growth conditions.
Expression of a Human Serum Albumin Fragment (Consisting of Subdomains IA, IB, and IIA) and a Study of Its Properties
Authors: Park David S. , Petersen Charles E. , Ha Chung‐Eun , Harohalli Krishna , Feix Jimmy B. , Bhagavan Nadhipuram V.
Published: July 2007

Site‐directed mutagenesis and a yeast expression system were used to synthesize a human serum albumin (HSA) fragment(amino acids 1‐297). The HSA fragment (half HSA) was evaluated with a number of biophysical techniques and found to be similar to the corresponding region in wild‐type HSA. Specifically, the circular dichroism spectra of half HSA and wild‐type HSA were superimposable, indicating that the highly alpha‐helical secondary structure of wild‐type HSA is preserved in half HSA. Additionally, half HSA was partially reactive with a polyclonal antibody against authentic HSA. Half HSA, which contains subdomain IIA, had an affinity for thyroxine and several thyroxine analogs, similar to that observed previously for wild‐type HSA. This study suggests that the production of recombinant HSA fragments will be useful for the study of HSA ligand interactions.
Effect of Rooperol on Collagen Synthesis and Cell Growth
Authors: Dietzsch Erin , Albrecht Carl F. d. V. , Parker M. Iqbal
Published: July 2007

The effect of rooperol on type I collagen synthesis in normal skin and lung fibroblasts and cell growth in normal and transformed fibroblasts was investigated. Low concentrations of rooperol selectively inhibited the growth of transformed cells while stimulating collagen synthesis in normal fibroblasts. Elevated collagen synthesis and deposition could impede tumour cell invasion and metastasis, implying that rooperol may be useful as an antimetastatic agent in the treatment of cancer.
Analysis of Protein Kinase C Isoforms Involved in the Activation of Laminin Receptor in Raw264.7 Macrophages
Authors: Oh Chun‐Do , Kang Shin‐Sung , Ha Mahn Joon , Chun Jang‐Soo
Published: July 2007

Adherence of hematopoietic macrophages to a laminin (LM) substratum requires protein kinase C (PKC)‐dependent activation of LM receptor. This study was performed to analyze PKC isoform(s) leading to the activation of LM receptor during Raw264.7 macrophage‐like cell adhesion to a LM substratum. Raw264.7 cells expressed multiple PKC isoforms, including alpha, betaI, delta, epsilon, zeta, lambda/iota and mu. Among the PKC isoforms expressed, selective activation of PKC delta and epsilon was sufficient to induce cell adhesion to LM. PKC‐dependent cell adherence was blocked by the selective inhibition of PKC delta, suggesting that PKC delta was the responsible PKC isoform leading to activation of LM receptor. PKC delta appeared to activate LM receptor in an intact microfilament‐dependent pathway, because disruption of microfilament inhibited cell adhesion to LM without affecting PKC delta activation.
Proteolysis of Synaptobrevin, Syntaxin, and Snap‐25 in Alveolar Epithelial Type II Cells
Authors: Zimmerman Un‐Jin P. , Malek Syeda K. , Liu Lin , Li Hong Lan
Published: July 2007

Synaptobrevin‐2, syntaxin‐1, and SNAP‐25 were identified in rat alveolar epithelial type II cells by Western blot analysis. Synaptobrevin‐2 was localized in the lamellar bodies, and syntaxin‐1 and SNAP‐25 were found in 0.4% Nonidet P40‐soluble and ‐insoluble fractions, respectively, of the type II cells. When the isolated type II cells were stimulated for secretion with calcium ionophore A23187 or with phorbol 12‐myristate 13‐acetate, these proteins were found to have been proteolyzed. Preincubation of cells with calpain inhibitor II (N‐acetylleucylleucylmethionine), however, prevented the proteolysis. Treatment of the cell lysate with exogenous calpain resulted in a time‐dependent decrease of these proteins. The data suggest that synaptobrevin, syntaxin, and SNAP‐25 are subject to proteolytic modification by activated calpain in intact type II cells stimulated for secretion.
Oxidative Stress and Calcium Homeostasis in Dystrophic Skin Fibroblasts
Authors: Degl'Innocenti Donatella , Pieri Alessandro , Rosati Fabiana , Ramponi Giampietro
Published: July 2007

Muscular dystrophy is a genetic disease that affects primarily skeletal muscle. The dystrophin absence has been related to the degeneration of muscle fibres. Indirect evidences suggest that oxidative stress may play a role in the pathogenesis of the disease, but the significance and precise extent of this contribution is poorly understood. In this paper we show that Becker Muscular Dystrophy (BMD) and Duchenne Muscular Dystrophy (DMD) skin fibroblasts are more susceptible to H2O2 treatment than are fibroblasts from unaffected persons. In particular, we found that, in growing DMD skin fibroblasts, the oxidative treatment resulted in significantly reduced growing capacity. We also investigated the concentrations of intracellular calcium during H2O2 treatment. The intracellular free calcium concentration increased by 22%, 35%, and 40% in unaffected, BMD, and DMD fibroblasts, respectively. However, the increase of the intracellular free calcium concentration is not related, as previously hypothesized, to a reduction of acylphosphatase concentrations, which seem to be unaffected by the H2O2 treatment, but rather to reduced enzyme activity.
Specific Processing of Poly(ADP‐Ribose) Polymerase, Accompanied by Activation of Caspase‐3 and Elevation/Reduction of Ceramide/Hydrogen Peroxide Levels, During Induction of Apoptosis in Host HL‐60 Cells Infected by the Human Granulocytic Ehrlichiosis (HGE) Agent
Authors: Dipietrantonio Anna M. , Hsieh Tze‐Chen , Wu Joseph M.
Published: July 2007

We studied the mechanism by which the human granulocytic ehrlichiosis (HGE) agent induces programmed cell death (apoptosis) in human promyelocytic HL‐60 leukemia cells. Using several New York HGE isolates, we show that the HGE agent‐elicited apoptosis is accompanied by increased processing of nuclear enzyme poly(ADP‐ribose) polymerase (PARP), concurrent with a noticeable increase in caspase 3 activities. A marked increase in the amounts of the signaling molecule ceramide but not of diacylglycerol was also observed in HGE agent‐infected HL‐60 cells, compared with the amounts in uninfected controls. Simultaneous or prior treatment of infected HL‐60 cells with the ceramide synthase inhibitor fumonisin B1 did not affect the magnitude of infection by the intracellular pathogen, as determined by both the presence of morulae and the expression of its outer surface membrane protein, p44. These results suggest that the observed changes in ceramide are generated through the sphingomyelinase pathway and not by way of de novo synthesis of ceramide. We also assayed for changes in intracellular hydrogen peroxide and show that the HGE agent causes a decrease in its concentrations in infected cells.
Lysophosphatidic Acid and Sphingosine 1‐Phosphate: Two Lipid Villains Provoking Cardiovascular Diseases?
Authors: Siess Wolfgang , Essler Markus , Brandl Richard
Published: July 2007

Lysophosphatidic acid (LPA) and sphingosine 1‐phosphate (S1P) are potent bioactive lipids with specific and multiple effects on cells of the vessel wall and blood platelets. In this paper we suggest that these lipid molecules are involved in atherogenesis, pathological vasoconstriction, plaque rupture, and intravascular thrombus formation, which leads us to propose new strategies for the prevention and therapy of cardiovascular diseases. The conclusions are hypothetical, in that the studies were so far mainly carried out on isolated cells or cultured cells in vitro and the results were extrapolated to the situation in vivo.
Molecular Analysis of the Saccharomyces cerevisiae YHR076w Gene
Authors: Ramos C. W. , GÜldener U. , Klein S. , Hegemann J. H. , Gonzalez S. , RodrÍguez‐Medina J. R.
Published: July 2007

Our results demonstrate that open reading frame (ORF) YHR076w on chromosome VIII of Saccharomyces cerevisiae that was previously described as a hypothetical gene is expressed. This ORF is transcribed as an mRNA of approximately 1,100 nucleotides. A 41.2‐kDa polypeptide and three others predicted to be modified forms of Yhr076wp are detected by Western blot with a Yhr076wp‐specific antibody. Promoter activity assays indicate that YHR076w transcription is regulated by carbon source and primarily by ethanol. Consistent with this observation, we have identified two potential ADR1 regulatory elements in the YHR076w upstream DNA region. Potential YAP1 and HSP elements are also identified in this region, suggesting other forms of regulation. YHR076w knockout strains do not exhibit any measurable growth or morphological phenotype under any conditions tested. However, increased YHR076w gene dosage confers a growth advantage to both wildtype and YHR076w knockout strains on 2% ethanol or 2% galactose medium in a low O2 growth environment. The fluorescence emitted by a Yhr076wp protein fusion to A. aquorin GFP colocalizes with the mitochondria in vivo.
Surface Tension and Density of Bismuth Germanate Melts as a Function of Composition and Temperature
Authors: Tan Rongri , Wang Qiang , Wang Lianwen , Li Chenxi , Lu Kunquan , Peng Shizheng , Hu Lin
Published: July 2007

The surface tension and density of xBi2O3–(1−x)GeO2 (BGO) melts have been measured systematically from their respective melting points up to around 1480 K within 0.25≤x≤0.86. With the addition of Bi2O3, the density of this system increased smoothly with a positive curvature. Deviation of molar volume from ideality of this system melts decreased firstly, past a minimum at about x=0.4, and then increased. Partial molar volumes of Bi2O3 and GeO2 have also been calculated based on the measured density data and compared with those of a binary bismuth borate system. On increasing the content of Bi2O3, the surface tension of BGO melts increased slowly when x<∼0.40, past a maximum at about x=0.50, and then decreased rapidly. In addition, the temperature coefficient of surface tension remained positive within the lower content range of Bi2O3, changed sign from positive to negative at about x=0.38, and then was almost independent of the composition within the measured temperature range when the Bi2O3 content was increased further.
Constrained Drying of an Aqueous Yttria‐Stabilized Zirconia Slurry on a Substrate II: Binary Particle Slurry
Authors: Lan Weihua , Xiao Ping
Published: July 2007

Binary‐sized particle slurries (binary slurries) prepared by mixing micro‐particles and electrostatically stabilized nano‐particle slurries (nano‐slurries) were cast onto metal substrates to form wet coatings and the drying process was studied. The highly charged nano‐particles were found to deposit on the surface of the micro‐particles, resulting in a decrease in the viscosity of the binary slurry. The drying kinetics were classified as an initial constant rate period (CRP), followed by a falling rate period. In the early stage of CRP, the movement of micro‐particles induced coating shrinkage and tensile stresses developed due to the constraint of the substrate. Thereafter, the nano‐slurry continued to dry and shrink around the static micro‐particles without further coating shrinkage, but with an increase in the stress. The addition of micro‐particles reduced the level of the maximum stress and prevented crack formation during drying. The microstructure of green coatings shows the presence of nano‐particles between micro‐particles that cement the micro‐particles together.