bluuebunny/crossref_metadata_2025 huggingface dataset:
Hip fractures and cognitive state: patient outcomes and proxies’ perceptions of the rehabilitation period
Authors: Rydholm Hedman Ann‐Marie , Heikkilä Kristina , Grafström Margareta , Strömberg Lars
Published: August 2008

Background.  Numerous studies are available on hip fracture and rehabilitation outcomes, some mention dementia but very few from a family/proxy perspective.

Aim.  To investigate whether cognitive state influences the hip fracture patients’ rehabilitation outcomes as well as the proxies’ perceptions of the 6‐month rehabilitation period.

Design.  A survey with structured and unstructured questions. Statistics and content analysis.

Methods.  The questionnaire was sent to 40 proxies of hip fracture patients with and without cognitive impairment, 32 replied. Statistics and content analysis were used to analyse the data.

Results.  In the cognitively impaired group, physical function decreased (P = 0.0241) as well as locomotion (P = 0.0005) compared to pre‐fracture. This group mainly participated in rehabilitation sessions in institutions (P = 0.0001) and their main support came from nursing staff. The cognitively impaired group assessed the rehabilitation period as being of a much lower quality than the cognitively intact group (P = 0.0048). In the impaired group, hindrances to rehabilitation were low level of staffing, and lack of access to rehabilitation resources such as physiotherapists.

Conclusions and relevance for clinical practice.  Hip fracture patients are a dichotomous group and cognition is decisive for physical and social outcomes as well as type of rehabilitation support.
The Development of Metacognitive Knowledge in Children and Adolescents: Major Trends and Implications for Education
Authors: Schneider Wolfgang
Published: August 2008

ABSTRACT— This article gives an overview of developmental trends in research on metacognition in children and adolescents. Whereas a first wave of studies focused on the assessment of declarative and procedural metacognitive knowledge in schoolchildren and adolescents, a second wave focused on very young children’s “theory of mind” (ToM). Findings from a recent longitudinal study are presented that demonstrate developmental links between early ToM and subsequent declarative metacognitive knowledge, mainly mediated by language competencies. The relevant literature further indicates that developmental trends in declarative and procedural metacognitive knowledge clearly differ. Whereas the findings for declarative metacognitive knowledge show steady improvement through childhood and adolescence, mainly due to increases in knowledge about strategies, the results are not similarly clear‐cut for procedural metacognition. Age trends observed for this component of metacognition are significant for self‐control activities but not pronounced for monitoring abilities. These findings have important implications for education, emphasizing the role of strategy training procedures in different instructional domains and illustrating teachers’ potential impact on the improvement of monitoring and control processes.
Dystrophia Helsinglandica: a new type of hereditary corneal recurrent erosions with late subepithelial fibrosis
Authors: Hammar Björn , Björck Erik , Lind Helena , Lagerstedt Kristina , Dellby Anette , Fagerholm Per
Published: August 2008

Purpose:  To describe the phenotype of an autosomal‐dominant corneal dystrophy with an early onset of recurrent corneal erosions and development of subepithelial fibrosis in the cornea, and also to exclude genetic linkage to known corneal dystrophies with autosomal‐dominant inheritance and clinical resemblance.

Methods:  We describe the medical history and clinical findings in individuals from a seven‐generation family with recurrent corneal erosions. A total of 43 individuals were evaluated by ophthalmological examination. Genomic DNA was prepared from peripheral blood and polymorphic microsatellite markers were analysed to study haplotypes surrounding genes causing corneal dystrophies with similar phenotypes.

Results:  Erosive symptoms usually lasted for between 1 and 10 days. By the age of 7 almost all of the affected individuals suffered from recurrent corneal erosions. The attacks generally declined in frequency and intensity from the late 20s, but all examined individuals had developed subepithelial fibrosis by the age of 37. The fibrosis generally started in the mid periphery and was followed in some family members by central fibrosis and the development of gelatinous superficial elevations. Only a marginal reduction of visual acuity was seen in a few individuals. The affected individuals did not share haplotypes for genetic microsatellite markers surrounding genes that are known to cause autosomal‐dominant corneal dystrophies.

Conclusion:  We describe a new type of autosomal‐dominant corneal disorder with recurrent corneal erosions and subepithelial fibrosis not significantly affecting visual acuity.
Quality Inspection of Flip Chip Solder Bumps Using Integrated Analytical, Numerical, and Experimental Modal Analyses
Authors: Yang Jin , Ume I. Charles
Published: August 2008

Solder bump inspection of surface mount packages has been a crucial process in the electronics manufacturing industry. A solder bump inspection system has been developed using laser ultrasound and interferometric techniques. In this research, modal analysis is important to correlate the defects with dynamic responses of packaged electronic devices under pulsed laser loading. The effect of solder bump defects on the mode frequencies and mode shapes is reported in this paper. The objective is to develop a modal analysis approach, which integrates analytical, numerical, and experimental methods. In particular, this paper discusses the analytical modeling, numerical modeling, and transient out-of-plane displacement measurements for a 6.35×6.35×0.6mm3 PB18 flip chip mounted on a FR4 board.
DNA Fragmentation in Microorganisms Assessed In Situ
Authors: Fernández José Luis , Cartelle Mónica , Muriel Lourdes , Santiso Rebeca , Tamayo María , Goyanes Vicente , Gosálvez Jaime , Bou Germán
Published: August 2008

Chromosomal DNA fragmentation may be a direct or indirect outcome of cell death. Unlike DNA fragmentation in higher eukaryotic cells, DNA fragmentation in microorganisms is rarely studied. We report an adaptation of a diffusion-based assay, developed as a kit, which allows for simple and rapid discrimination of bacteria with fragmented DNA. Intact cells were embedded in an agarose microgel on a slide, incubated in a lysis buffer to partially remove the cell walls, membranes, and proteins, and then stained with a DNA fluorochrome, SYBR Gold. Identifying cells with fragmented DNA uses peripheral diffusion of DNA fragments. Cells without DNA fragmentation show only limited spreading of DNA fiber loops. These results have been seen in several gram-negative and gram-positive bacteria, as well as in yeasts. Detection of DNA fragmentation was confirmed by fluoroquinolone treatment and by DNA breakage detection-fluorescence in situ hybridization.
Proteus mirabilis
with spontaneously fragmented DNA during exponential and stationary growth or
Escherichia coli
with DNA damaged after exposure to hydrogen peroxide or antibiotics, such as ciprofloxacin or ampicillin, was clearly detected. Similarly, fragmented DNA was detected in
Saccharomyces cerevisiae
after amphotericin B treatment. Our assay may be useful for the simple and rapid evaluation of DNA damage and repair as well as cell death, either spontaneous or induced by exogenous stimuli, including antimicrobial agents or environmental conditions.
Metabolic Microenvironmental Control by Photosynthetic Biofilms under Changing Macroenvironmental Temperature and pH Conditions
Authors: Bissett Andrew , Reimer Andreas , de Beer Dirk , Shiraishi Fumito , Arp Gernot
Published: August 2008

Ex situ microelectrode experiments, using cyanobacterial biofilms from karst water creeks, were conducted under various pH, temperature, and constant-alkalinity conditions to investigate the effects of changing environmental parameters on cyanobacterial photosynthesis-induced calcification. Microenvironmental chemical conditions around calcifying sites were controlled by metabolic activity over a wide range of photosynthesis and respiration rates, with little influence from overlying water conditions. Regardless of overlying water pH levels (from 7.8 to 8.9), pH at the biofilm surface was approximately 9.4 in the light and 7.8 in the dark. The same trend was observed at various temperatures (4°C and 17°C). Biological processes control the calcium carbonate saturation state (Ω) in these and similar systems and are able to maintain Ω at approximately constant levels over relatively wide environmental fluctuations. Temperature did, however, have an effect on calcification rate. Calcium flux in this system is limited by its diffusion coefficient, resulting in a higher calcium flux (calcification and dissolution) at higher temperatures, despite the constant, biologically mediated pH. The ability of biological systems to mitigate the effects of environmental perturbation is an important factor that must be considered when attempting to predict the effects of increased atmospheric partial CO2pressure on processes such as calcification and in interpreting microfossils in the fossil record.
Identification of a Hypervariable Region Containing NewLegionella pneumophilaIcm/Dot Translocated Substrates by Using the ConservedicmQRegulatory Signature
Authors: Zusman Tal , Degtyar Elena , Segal Gil
Published: August 2008

Legionella pneumophilais an intracellular pathogen that has been shown to utilize the Icm/Dot type IV secretion system for pathogenesis. This system was shown to be composed of Icm/Dot complex components, accessory proteins, and a large number of translocated substrates. In this study, comparison of theicmQregulatory regions from manyLegionellaspecies revealed a conserved regulatory sequence that includes theicmQ−10 promoter element. Mutagenesis of this conserved regulatory element indicated that each of the nucleotides in it affects the level of expression of theicmQgene but not in a uniform fashion. A genomic analysis discovered that four additional genes inL. pneumophilacontain this conserved regulatory sequence, which was found to function similarly in these genes as well. Examination of these four genes indicated that they are dispensable for intracellular growth, but two of them were found to encode new Icm/Dot translocated substrates (IDTS). Comparison of the genomic regions encoding these two IDTS among the four availableL. pneumophilagenomic sequences indicated that one of these genes is located in a hypervariable genomic region, which was shown before to contain an IDTS-encoding gene. Translocation analysis that was performed for nine proteins encoded from this hypervariable genomic region indicated that six of them are new IDTS which are translocated into host cells in an Icm/Dot-dependent manner. Furthermore, a bioinformatic analysis indicated that additionalL. pneumophilagenomic regions that contain several neighboring IDTS-encoding genes are hypervariable in gene content.
Role of Protein Kinase A in
Trypanosoma cruzi
Authors: Bao Yi , Weiss Louis M. , Braunstein Vicki L. , Huang Huan
Published: August 2008

Protein kinase A (PKA) is an important mediator of many signal transduction pathways that occur in eukaryotic cells, and it has been implicated as a regulator of stage differentiation in
Trypanosoma cruzi
. To evaluate the importance of the PKA catalytic subunit of
T. cruzi
(TcPKAc), a gene encoding a PKA inhibitor (PKI) containing a specific PKA pseudosubstrate, R-R-N-A, was subcloned into a pTREX vector and introduced into epimastigotes by electroporation. Expression of PKI has a lethal effect in this parasite. Similarly, a pharmacological inhibitor, H89, killed epimastigotes at a concentration of 10 μM. To understand the biology of PKA, identification of the particular substrates of this enzyme is essential. Using a yeast two-hybrid system, 38 candidates interacting with TcPKAc were identified. Eighteen of these were hypothetical proteins with unknown functions, while the others had putative or known functions. The entire open reading frames of eight genes presumably important in regulating
T. cruzi
growth, adaptation, and differentiation, including a type III PI3 kinase (Vps34), a putative PI3 kinase, a putative mitogen-activated extracellular signal-regulated kinase, a cyclic AMP (cAMP)-specific phosphodiesterase (PDEC2), a hexokinase, a putative ATPase, a DNA excision repair protein, and an aquaporin were confirmed to interact with TcPKAc in the yeast
Saccharomyces cerevisiae
under the highest stringency selection conditions, and PKA phosphorylated the recombinant proteins of these genes. Taken together, these findings demonstrate the importance of cAMP-PKA signaling in this organism.
Polar Localization and Compartmentalization of ClpP Proteases during Growth and Sporulation inBacillus subtilis
Authors: Kain James , He Gina G. , Losick Richard
Published: August 2008

Spatial control of proteolysis is emerging as a common feature of regulatory networks in bacteria. In the spore-forming bacteriumBacillus subtilis, the peptidase ClpP can associate with any of three ATPases: ClpC, ClpE, and ClpX. Here, we report that ClpCP, ClpEP, and ClpXP localize in foci often near the poles of growing cells and that ClpP and the ATPase are each capable of polar localization independently of the other component. A region of ClpC containing an AAA domain was necessary and sufficient for polar localization. We also report that ClpCP and ClpXP proteases differentially localize to the forespore and mother cell compartments of the sporangium during spore formation. Moreover, model substrates for each protease created by appending recognition sequences for ClpCP or ClpXP to the green fluorescent protein were preferentially eliminated from the forespore or the mother cell, respectively. Biased accumulation of ClpCP in the forespore may contribute to the cell-specific activation of the transcription factor σFby preferential ClpCP-dependent degradation of the anti-σFfactor SpoIIAB.
The
amt
Gene Cluster of the Heterocyst-Forming Cyanobacterium
Anabaena
sp. Strain PCC 7120
Authors: Paz-Yepes Javier , Merino-Puerto Victoria , Herrero Antonia , Flores Enrique
Published: August 2008

The genome of the heterocyst-forming cyanobacterium
Anabaena
sp. strain PCC 7120 bears a gene cluster including three
amt
genes that, based on homology of their protein products, we designate
amt4
,
amt1
, and
amtB
. Expression of the three genes took place upon ammonium withdrawal in combined nitrogen-free medium and was NtcA dependent. The genes were transcribed independently, but an
amt4-amt1
dicistronic transcript was also produced, and expression was highest for the
amt1
gene. A mutant with the whole
amt
region removed could grow under laboratory conditions using ammonium, nitrate, or dinitrogen as the nitrogen source.
Highly Efficient In Vitro Site-Specific Recombination System Based on
Streptomyces
Phage φBT1 Integrase
Authors: Zhang Lin , Ou Xijun , Zhao Guoping , Ding Xiaoming
Published: August 2008

The
Streptomyces
phage φBT1 encodes a site-specific integrase of the large serine recombinase subfamily. In this report, the enzymatic activity of the φBT1 integrase was characterized in vitro. We showed that this integrase has efficient integration activity with substrate DNAs containing
attB
and
attP
sites, independent of DNA supercoiling or cofactors. Both intra- and intermolecular recombinations proceed with rapid kinetics. The recombination is highly specific, and no reactions are observed between pairs of sites including
attB
and
attL
,
attB
and
attR
,
attP
and
attL
, or
attP
and
attR
or between two identical
att
sequences; however, a low but significant frequency of excision recombination between
attL
and
attR
is observed in the presence of the φBT1 integrase alone. In addition, for efficient integration, the minimal sizes of
attB
and
attP
are 36 bp and 48 bp, respectively. This site-specific recombination system is efficient and simple to use; thus, it could have applications for the manipulation of DNA in vitro.
The Growth-Promoting and Stress Response Activities of the
Bacillus subtilis
GTP Binding Protein Obg Are Separable by Mutation
Authors: Kuo Shrin , Demeler Borries , Haldenwang W. G.
Published: August 2008

Bacillus subtilis
Obg is a ribosome-associating GTP binding protein that is needed for growth, sporulation, and induction of the bacterium's general stress regulon (GSR). It is unclear whether the roles of Obg in sporulation and stress responsiveness are direct or a secondary effect of its growth-promoting functions. The present work addresses this question by an analysis of two
obg
alleles whose phenotypes argue for direct roles for Obg in each process. The first allele [
obg
(
G92D
)] encodes a missense change in the protein's highly conserved “obg fold” region. This mutation impairs cell growth and the ability of Obg to associate with ribosomes but fails to block sporulation or the induction of the GSR. The second
obg
mutation [
obg
(Δ
22
)] replaces the 22-amino-acid carboxy-terminal sequence of Obg with an alternative 26-amino-acid sequence. This Obg variant cofractionates with ribosomes and allows normal growth but blocks sporulation and impairs the induction of the GSR. Additional experiments revealed that the block on sporulation occurs early, preventing the activation of the essential sporulation transcription factor Spo0A, while inhibition of the GSR appears to involve a failure of the protein cascade that normally activates the GSR to effectively catalyze the reactions needed to activate the GSR transcription factor (σ
B
).
ON THE SELF-ADJOINTNESS AND DOMAIN OF PAULI–FIERZ TYPE HAMILTONIANS
Authors: HASLER D. , HERBST I.
Published: August 2008

We prove a general theorem about the self-adjointness and domain of Pauli–Fierz type Hamiltonians. Our proof is based on commutator arguments which allow us to treat fields with non-commuting components. As a corollary, it follows that the domain of the Hamiltonian of non-relativistic QED with Coulomb interactions is independent of the coupling constant.
HÖLDER CONTINUITY OF THE INTEGRATED DENSITY OF STATES FOR MATRIX-VALUED ANDERSON MODELS
Authors: BOUMAZA HAKIM
Published: August 2008

We study a class of continuous matrix-valued Anderson models acting on L2(ℝd) ⊗ ℂN. We prove the existence of their Integrated Density of States for any d ≥ 1 and N ≥ 1. Then, for d = 1 and for arbitrary N, we prove the Hölder continuity of the Integrated Density of States under some assumption on the group GμE generated by the transfer matrices associated to our models. This regularity result is based upon the analoguous regularity of the Lyapounov exponents associated to our model, and a new Thouless formula which relates the sum of the positive Lyapounov exponents to the Integrated Density of States. In the final section, we present an example of matrix-valued Anderson model for which we have already proved, in a previous article, that the assumption on the group GμE is verified. Therefore, the general results developed here can be applied to this model.
EFFECT OF COATING THICKNESS ON THE PROPERTIES OF TiN COATINGS DEPOSITED ON TOOL STEELS USING CATHODIC ARC PVD TECHNIQUE
Authors: MUBARAK A. , AKHTER PARVEZ , HAMZAH ESAH , MOHD TOFF MOHD RADZI HJ. , QAZI ISHTIAQ A.
Published: August 2008

Titanium nitride ( TiN ) widely used as hard coating material, was coated on tool steels, namely on high-speed steel (HSS) and D2 tool steel by physical vapor deposition method. The study concentrated on cathodic arc physical vapor deposition (CAPVD), a technique used for the deposition of hard coatings for tooling applications, and which has many advantages. The main drawback of this technique, however, is the formation of macrodroplets (MDs) during deposition, resulting in films with rougher morphology. Various standard characterization techniques and equipment, such as electron microscopy, atomic force microscopy, hardness testing machine, scratch tester, and pin-on-disc machine, were used to analyze and quantify the following properties and parameters: surface morphology, thickness, hardness, adhesion, and coefficient of friction (COF) of the deposited coatings. Surface morphology revealed that the MDs produced during the etching stage, protruded through the TiN film, resulting in film with deteriorated surface features. Both coating thickness and indentation loads influenced the hardness of the deposited coatings. The coatings deposited on HSS exhibit better adhesion compared to those on D2 tool steel. Standard deviation indicates that the coating deposited with thickness around 6.7 μm showed the most stable trend of COF versus sliding distance.
INFLUENCE OF SUBSTRATE TOPOGRAPHY ON THE NUCLEATION AND GROWTH OF 321 STAINLESS STEEL THIN FILMS PRODUCED BY MAGNETRON SPUTTERING
Authors: JIN YONGZHONG , LIU DONGLIANG , WU WEI , SUN YALI , YU ZUXIAO , LUO HONG
Published: August 2008

We have investigated the effects of substrate topography on the nucleation and growth behavior of 321 stainless steel (ss) films, introducing textured surfaces into mica substrates by the abrasion treatment. In this study, two groups of samples were prepared at three different sputtering time within 12 s using radio frequency (r.f.) magnetron sputtering and characterized by atomic force microscopy. Good nucleation uniformity has been obtained on the unabraded mica substrates due to the statistical distribution of nucleation sites. Especially, we have already observed an interesting unusual nucleation phenomenon, the island–rim structure on the abraded mica substrates after 4 s, where the island is fractal-like and the rim around the island was only occupied by few grains for nucleation. These ramified islands were located at the wide grooves introduced as predominate nucleation sites. The island–rim structure formed in initial nucleation process is closely associated with x, y velocity components of surface atoms and the distribution of active sites (related intimately to the surface free energy σ and strain energy ε) for nucleation. With the increasing of the sputtering time, voids and overlarge grains have been observed in the island–rim region after the sputtering time of 8 s and 12 s, respectively.
AGGREGATION OF P-TERPHENYL ALONG WITH PMMA/SA AT THE LANGMUIR AND LANGMUIR–BLODGETT FILMS
Authors: HUSSAIN SYED ARSHAD , ISLAM MD. N. , LEEMAN HUGO , BHATTACHARJEE DEBAJYOTI
Published: August 2008

Molecular aggregation and monolayer characteristics of non-amphiphilic p-terphenyl (TP) mixed with either polymethyl methacrylate (PMMA) or stearic acid (SA) at the air–water interface were investigated. The miscibility of the two components was evaluated by measuring and analyzing surface pressure versus area per molecule (π–A) isotherm. Both attractive and repulsive interactions between the sample (TP) and the matrix (PMMA or SA) were observed depending on the composition and microenvironment. TP and PMMA/SA were not completely miscible in the mixed monolayer. Aggregation and phase separation between sample TP and matrix molecule were revealed by UV–Vis absorption spectroscopic studies and confirmed by scanning electron micrograph of Langmuir–Blodgett films.
CdS NANORODS FABRICATED BY ICP-ASSISTED MAGNETRON SPUTTERING AT ROOM TEMPERATURE
Authors: HUANG S. Y. , XU S. , LONG J. D. , CHAI J. W. , CHENG Q. J.
Published: August 2008

Cadmium sulfide ( CdS ) nanocrystals are successfully fabricated on glass and silicon substrates at room temperature with low-frequency (460 kHz) inductively coupled plasma assisted magnetron sputtering technique. Both size and shape can be controlled by changing deposition parameters and substrates. Field-emission scanning electron microscope, energy dispersive X-ray spectroscopy, and X-ray diffraction are adopted to measure the properties of CdS nanorods.
SHIPS AS HABITATS: BIOFOULING — A PROBLEM THAT REQUIRES GLOBAL SOLUTIONS
Authors: RITTSCHOF DAN
Published: August 2008

Colonization of ship hulls by living organisms, which occurs on molecular, microbial and macro organism levels, decreases ship performance, increases costs and is a biological problem with global consequences. Managing fouling is necessary for efficient economics and to prevent environmental damage due to introduction of invasive species. Colonization is managed by broad spectrum long-lived toxins which kill colonizers. Broad spectrum long-lived toxins build up and impact environments. Toxins damage ecosystems and directly or indirectly kill food species. Ideally, novel antifouling approaches will be compatible with existing business models and with the environment. A mixture of short-lived biologically active molecules that manage colonization has this potential. The mixture would contain a short-lived toxin that managed colonization of organisms that have no behavior and then additional molecules that interfere with the process of colonization by organisms with behavior and those that attach as part of a change in life stage. Environmentally benign antifouling approaches are novel and require cooperation rather than competition or adversarial relationships. They require cooperation by individuals with expertise from business, governmental agencies and academia. The science is likely to be easier than the necessary changes in philosophy and governance required to successfully address this and other complex global problems.
YOU MAKE IT, I BREAK IT
Authors: LEAR MARTIN J. , HOBLEY JONATHAN
Published: August 2008

The changing state of our molecular world involves the making and breaking of bonds. Some researchers make chemical structures, others break them. Both approaches play an important part in the development of new drugs, detectors and materials. However, modern endeavors in research involve understanding and overlapping the interfaces of a myriad of disciplines. No more do scientific pioneers work alone. In this article, we shall give background of our selected scientific endeavors, and briefly show how, within chemistry, we can bond seemingly disparate disciplines together in unexpected ways in a collective attempt to deliver new materials and hybrid systems.
SUMS OF SQUARES AND SUMS OF TRIANGULAR NUMBERS INDUCED BY PARTITIONS OF 8
Authors: BARUAH NAYANDEEP DEKA , COOPER SHAUN , HIRSCHHORN MICHAEL
Published: August 2008

Let rk(n) and tk(n) denote the number of representations of an integer n as a sum of k squares, and as a sum of k triangular numbers, respectively. We prove that [Formula: see text] and therefore the study of the sequence t8(n) is reduced to the study of subsequences of r8(n). We give an additional 21 analogous results for sums of squares and sums of triangular numbers induced by partitions of 8. We give a brief indication of what happens for the case k ≥ 9.
EXPONENTS OF CLASS GROUPS OF REAL QUADRATIC FIELDS
Authors: CHAKRABORTY KALYAN , LUCA FLORIAN , MUKHOPADHYAY ANIRBAN
Published: August 2008

In this paper, we show that the number of real quadratic fields 𝕂 of discriminant Δ𝕂 < x whose class group has an element of order g (with g even) is ≥ x1/g/5 if x > x0, uniformly for positive integers g ≤ ( log log x)/(8 log log log x). We also apply the result to find real quadratic number fields whose class numbers have many prime factors.
INFINITE FAMILIES OF FORMULAS FOR SUMS OF INTEGER SQUARES
Authors: MASRI NADIA
Published: August 2008

In 2002, Milne [5, 6] obtained ten infinite families of formulas for the sums of integer squares. Recently, Long and Yang [4] reproved four of these identities using modular forms on various subgroups. In this paper, we prove the remaining six, and show that all of the identities can be proved by interpreting them in terms of modular forms for Γ0(4).
AN "ANTI-HASSE PRINCIPLE" FOR PRIME TWISTS
Authors: CLARK PETE L.
Published: August 2008

Given an algebraic curve C/ℚ having points everywhere locally and endowed with a suitable involution, we show that there exists a positive density family of prime quadratic twists of C violating the Hasse principle. The result applies in particular to wN-Atkin–Lehner twists of most modular curves X0(N) and to wp-Atkin–Lehner twists of certain Shimura curves XD+.
EXPLICIT GALOIS GROUP REALIZATIONS
Authors: PINEDA-RUELAS MARIO , VILLA-SALVADOR GABRIEL D.
Published: August 2008

We study the embedding problem with abelian kernel and we obtain a homogeneous system of equations, which leads directly to the explicit realization of a finite group with certain properties. We give an example motivated by finding explicitly nonsolitary fields of degree 18 over ℚ.
DIRICHLET TRUNCATIONS OF THE RIEMANN ZETA FUNCTION IN THE CRITICAL STRIP POSSESS ZEROS NEAR EVERY VERTICAL LINE
Authors: FARAG HANY M.
Published: August 2008

We study the zeros of the finite truncations of the alternating Dirichlet series expansion of the Riemann zeta function in the critical strip. We do this with an (admittedly highly) ambitious goal in mind. Namely, that this series converges to the zeta function (up to a trivial term) in the critical strip and our hope is that if we can obtain good estimates for the zeros of these approximations it may be possible to generalize some of the results to zeta itself. This paper is a first step towards this goal. Our results show that these finite approximations have zeros near every vertical line (so no vertical strip in this region is zero-free). Furthermore, we give upper bounds for the imaginary parts of the zeros (the real parts are pinned). The bounds are numerically very large. Our tools are: the inverse mapping theorem (for a perturbative argument), the prime number theorem (for counting primes), elementary geometry (for constructing zeros of a related series), and a quantitative version of Kronecker's theorem to go from one series to another.
EVERYWHERE UNRAMIFIED AUTOMORPHIC COHOMOLOGY FOR SL3(ℤ)
Authors: ASH AVNER , POLLACK DAVID
Published: August 2008

We conjecture that the only irreducible cuspidal automorphic representations for GL 3/ℚ of cohomological type and level 1 are (up to twisting) the symmetric square lifts of classical cuspforms on GL 2/ℚ of level 1. We present computational evidence for this conjecture.
A new class of nature-inspired algorithms for self-adaptive peer-to-peer computing
Authors: Ko Steven Y. , Gupta Indranil , Jo Yookyung
Published: August 2008

We present, and evaluate benefits of, a design methodology for translating natural phenomena represented as mathematical models, into novel, self-adaptive, peer-to-peer (p2p) distributed computing algorithms (
protocols
). Concretely, our first contribution is a set of techniques to translate discrete
sequence equations
(also known as difference equations) into new p2p protocols called
sequence protocols
. Sequence protocols are self-adaptive, scalable, and fault-tolerant, with applicability in p2p settings like Grids. A sequence protocol is a set of probabilistic local and message-passing actions for each process. These actions are translated from terms in a set of source sequence equations. Individual processes do not simulate the source sequence equations completely. Instead, each process executes probabilistic local and message passing actions, so that the emergent round-to-round behavior of the sequence protocol in a p2p system can be probabilistically predicted by the source sequence equations. The article's second contribution is the design and evaluation of a set of sequence protocols for detection of two global triggers in a distributed system: threshold detection and interval detection. This article's third contribution is a new self-adaptive Grid computing protocol called HoneyAdapt. HoneyAdapt is derived from sequence equations modeling adaptive bee foraging behavior in nature. HoneyAdapt is intended for Grid applications that allow Grid clients, at run-time, a choice of algorithms for executing chunks of the application's dataset. HoneyAdapt tells each Grid client how to adaptively select at run-time, for each chunk it receives, a good algorithm for computing the chunk—this selection is based on continuous feedback from other clients. Finally, we design a variant of HoneyAdapt, called HoneySort, for application to Grid parallelized sorting settings using the master-worker paradigm. Our evaluation of these contributions consists of mathematical analysis, large-scale trace-based simulation results, and experimental results from a HoneySort deployment.
Extending futex for kernel to user notification
Authors: Bahmann Helge , Froitzheim Konrad
Published: August 2008

Threads in reactive applications need to service a multitude of events from different sources such as device drivers, communication channels or cooperating threads. While notification about these events can conceptually be understood as a form of "synchronization", most operating systems (including Linux) do not provide a unified abstraction. This paper proposes to separate event delivery and notification, and to provide unified event notification through general-purpose synchronization objects. It demonstrates how this unified mechanism can be implemented in Linux as an extension of the futex mechanism to allow notification from kernel-space. Required modifications are discussed and their impact is assessed. The new event notification mechanism allows to move many thread activation policy decisions into user-space, with benefits for multi-threaded reactive applications: This is demonstrated in a modification of the leader/followers pattern with considerable performance benefits.
Plan 9 authentication in Linux
Authors: Ganti Ashwin
Published: August 2008

In Linux, applications like su and login currently run as root in order to access authentication information and set or alter the identity of the process. In such cases, if the application is compromised while running as a privileged user, the entire system can become vulnerable. An alternative approach is taken by the Plan 9 operating system from Bell Labs, which runs such applications as a non-privileged user and relies on a kernel-based capability device working in coordination with an authentication server to provide the same services. This avoids the risk of an application vulnerability becoming a system vulnerability.

This paper discusses the extension of Linux authentication mechanisms to allow the use of the Plan 9 approach with existing Linux applications in order to reduce the security risks mentioned earlier. It describes the port of the Plan 9 capability device as a character device driver for the Linux kernel. It also describes the port of the Plan 9 authentication server and the implementation of a PAM module which allows the use of these new facilities.
It is now possible to restrain processes like login and su from the uncontrolled setuid bit and make them run on behalf of an unprivileged user in Linux
.
Leptin-induced endothelial dysfunction in obesity
Authors: Korda Mykhaylo , Kubant Ruslan , Patton Stephen , Malinski Tadeusz
Published: August 2008

Hyperleptinemia accompanying obesity affects endothelial nitric oxide (NO) and is a serious factor for vascular disorders. NO, superoxide (O2−), and peroxynitrite (ONOO−) nanosensors were placed near the surface (5 ± 2 μm) of a single human umbilical vein endothelial cell (HUVEC) exposed to leptin or aortic endothelium of obese C57BL/6J mice, and concentrations of calcium ionophore (CaI)-stimulated NO, O2−, ONOO− were recorded. Endothelial NO synthase (eNOS) expression and l-arginine concentrations in HUVEC and aortic endothelium were measured. Leptin did not directly stimulate NO, O2−, or ONOO− release from HUVEC. However, a 12-h exposure of HUVEC to leptin increased eNOS expression and CaI-stimulated NO (625 ± 30 vs. 500 ± 24 nmol/l control) and dramatically increased cytotoxic O2− and ONOO− levels. The [NO]-to-[ONOO−] ratio ([NO]/[ONOO−]) decreased from 2.0 ± 0.1 in normal to 1.30 ± 0.1 in leptin-induced dysfunctional endothelium. In obese mice, a 2.5-fold increase in leptin concentration coincided with 100% increase in eNOS and about 30% decrease in intracellular l-arginine. The increased eNOS expression and a reduced l-arginine content led to eNOS uncoupling, a reduction in bioavailable NO (250 ± 10 vs. 420 ± 12 nmol/l control), and an elevated concentration of O2− (240%) and ONOO− (70%). l-Arginine and sepiapterin supplementation reversed eNOS uncoupling and partially restored [NO]/[ONOO−] balance in obese mice. In obesity, leptin increases eNOS expression and decreases intracellular l-arginine, resulting in eNOS an uncoupling and depletion of endothelial NO and an increase of cytotoxic ONOO−. Hyperleptinemia triggers an endothelial NO/ONOO− imbalance characteristic of dysfunctional endothelium observed in other vascular disorders, i.e., atherosclerosis and diabetes.
Presenilins: Members of the γ-Secretase Quartets, But Part-Time Soloists Too
Authors: Wakabayashi Tomoko , De Strooper Bart
Published: August 2008

The presenilins in combination with other proteins generate different γ-secretases, which are involved in the regulated intramembrane proteolysis of a variety of proteins. Understanding the specificity and regulation of these proteases will potentially lead to novel therapeutics for Alzheimer’s disease and cancer. Presenilins appear also to exert additional functions outside of the γ-secretase quartets, which needs further investigation.
COOH-Terminal Truncated HBV X Protein Plays Key Role in Hepatocarcinogenesis
Authors: Ma Ning-Fang , Lau Sze Hang , Hu Liang , Xie Dan , Wu Jun , Yang Jun , Wang Yi , Wu Meng-Chao , Fung Jackie , Bai Xueyan , Tzang Chi-Hung , Fu Li , Yang Mengsu , Su Yan An , Guan Xin-Yuan
Published: August 2008

Purpose: X protein (HBx), a product of hepatitis B virus, has been closely associated with the development of hepatocellular carcinoma (HCC). Based on observations that the COOH-terminal truncated HBx was frequently detected in HCC, the aim of this study is to evaluate the function of COOH-terminal truncated HBx in hepatocarcinogenesis.

Experimental Design: Expression pattern of HBx was analyzed by immunohistochemistry on tissue microarray containing 194 pairs of HCCs and their matched nontumor liver tissues. MIHA and HepG2 cells transfected with full-length (X2) and COOH-terminal truncated HBx (X1) were tested for their ability to grow in soft agar and form tumors in vivo. Proliferation and apoptosis were assessed using 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide inner salt and terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling assays, respectively. To gain additional insight, the expression profile of HepG2-X2 and HepG2-X1 were compared using cDNA microarray.

Results: COOH-terminal truncated HBx was frequently detected in HCCs (79.3%, n = 111), and our in vitro and in vivo studies showed that the truncated rather than the full-length HBx could effectively transform immortalized liver cell line MIHA. Interestingly, expression profiling revealed differential expression of key genes implicated in the control of cell cycle and apoptosis.

Conclusions: These findings strongly suggest that the COOH-terminal truncated HBx plays a critical role in the HCC carcinogenesis via the activation of cell proliferation.
Clinical-Translational Approaches to the Nm23-H1 Metastasis Suppressor
Authors: Steeg Patricia S. , Horak Christine E. , Miller Kathy D.
Published: August 2008

Nm23-H1 significantly reduces metastasis without effects on primary tumor size and was the first discovered metastasis suppressor gene. At least three mechanisms are thought to contribute to the metastasis-suppressive effect of Nm23-H1: (a) its histidine kinase activity toward ATP-citrate lyase, aldolase C, and the kinase suppressor of ras, with the last inactivating mitogen-activated protein kinase signaling; (b) binding proteins that titer out “free” Nm23-H1 and inhibit its ability to suppress metastasis; and (c) altered gene expression downstream of Nm23-H1, particularly an inverse association with the lysophosphatidic acid receptor endothelial differentiation gene-28 (EDG2). Most metastasis suppressor genes, including Nm23-H1, affect metastatic colonization, which is the outgrowth of tumor cells in distant locations; therefore, they are of high translational interest. A phase II trial is ongoing to test the hypothesis that a compound, high-dose medroxyprogesterone acetate (MPA), used as an unconventional gluocorticoid, will stimulate breast cancer cells to reexpress Nm23-H1 and limit subsequent metastatic colonization.
Enhanced Antitumor Therapy by Inhibition of p21waf1 in Human Malignant Mesothelioma
Authors: Lazzarini Raffaella , Moretti Simona , Orecchia Sara , Betta Pier-Giacomo , Procopio Antonio , Catalano Alfonso
Published: August 2008

Purpose: The p21 cyclin-dependent kinase inhibitor was frequently expressed in human malignant pleural mesothelioma (MPM) tissues as well as cell lines. Recent data indicate that p21 keeps tumor cells alive after DNA damage, favoring a survival advantage. In this study, we assessed the possibility of p21 suppression as a therapeutic target for MPM.

Experimental Design: We established two different MPM-derived (from H28 and H2052 cells) subclones using vector-based short hairpin RNA (shRNA). Then, chemosensitivity against low doses of antineoplastic DNA-damaging agents was investigated by colony formation assays, and furthermore, the type of cell response induced by these drugs was analyzed. To examine the effect of p21 shRNA on chemosensitivity in vivo, tumor formation assays in nude mice were done.

Results: In colony formation assay, the IC50 of doxorubicin was 33 ± 3.0 nmol/L in p21 shRNA-transfected cells with respect to 125 ± 10 nmol/L of control vector–transfected cells. This enhancement of growth inhibition was achieved by converting a senescence-like growth arrest to apoptosis in response to doxorubicin, etoposide, and CPT11. In the in vivo assays, CPT11 and loss-of-expression of p21 in combination led to considerable suppression of tumor growth associated with a substantially enhanced apoptotic response, whereas CPT11 alone was ineffective at inducing these responses.

Conclusions: These results indicated that p21 might play an important role in chemosensitivity to anticancer agents, and the suppression of its expression might be a potential therapeutic target for MPM.
Incidence and Prognostic Impact of FoxP3+ Regulatory T Cells in Human Gliomas
Authors: Heimberger Amy B. , Abou-Ghazal Mohamed , Reina-Ortiz Chantal , Yang David S. , Sun Wei , Qiao Wei , Hiraoka Nobuyoshi , Fuller Gregory N.
Published: August 2008

Purpose: The incidence of regulatory T cells (Treg) in intrinsic central nervous system malignancies is unknown. Immunotherapeutic approaches that inhibit the Treg population may be limited to a subset of patients with gliomas. Our hypothesis is that only the most malignant gliomas have a prominent glioma-infiltrating Treg population that contributes to the immunosuppressive biology and that the presence of Tregs is a negative prognostic variable.

Experimental Design: We measured the incidence of Tregs in 135 glial tumors (including all pathologic types) in a glioma microarray using immunohistochemical analysis. Results were categorized according to the total number of Tregs within the tumors. Correlation of the presence of Tregs with prognosis was evaluated using univariate and multivariate analyses.

Results: Tregs were not present in normal brain tissue and were very rarely found in low-grade gliomas and oligodendrogliomas. We observed significant differences in the prevalence of Tregs between astrocytic and oligodendroglial tumors, between tumors of different grades, and between different pathologic types of tumors. We identified Tregs most frequently in glioblastoma multiforme (GBM) but very rarely in low-grade astrocytomas. The presence of Tregs within GBMs did not alter the median survival in patients from whom the tumors were obtained.

Conclusions: Treg infiltration differed significantly in the tumors according to lineage, pathology, and grade. Tregs seemed to have the highest predilection for tumors of the astrocytic lineage and specifically in the high-grade gliomas, such as GBM. In both univariate and multivariate analysis, the presence of Tregs in GBMs seemed to be prognostically neutral.
Survivin: Key Regulator of Mitosis and Apoptosis and Novel Target for Cancer Therapeutics
Authors: Mita Alain C. , Mita Monica M. , Nawrocki Steffan T. , Giles Francis J.
Published: August 2008

Survivin, a member of the family of inhibitor of apoptosis proteins, functions as a key regulator of mitosis and programmed cell death. Initially, survivin was described as an inhibitor of caspase-9. However, over the last years, research studies have shown that the role of survivin in cancer pathogenesis is not limited to apoptosis inhibition but also involves the regulation of the mitotic spindle checkpoint and the promotion of angiogenesis and chemoresistance. Survivin gene expression is transcriptionally repressed by wild-type p53 and can be deregulated in cancer by several mechanisms, including gene amplification, hypomethylation, increased promoter activity, and loss of p53 function. This article reviews the multiple functions of survivin in the regulation of apoptosis, the promotion of tumorigenesis, and the development of survivin inhibitors as a novel anticancer therapeutic strategy.
Effect of Speaking Rate on the Identification of Word Boundaries
Authors: Schwab Sandra , Miller Joanne L. , Grosjean François , Mondini Michèle
Published: August 2008

Two experiments were conducted to determine whether listeners’ ability to use allophonic variation to identify word boundaries is influenced by speaking rate. Listeners in both experiments were presented two-word sequences (such as great eyes) spoken by naturally fast and naturally slow talkers; in one experiment the sequences were presented in quiet and in the other they were presented in noise. The listeners’ task was to identify the intended sequence from among four choices with alternative segmentations (e.g. great eyes, gray ties, great ties, gray eyes). In both experiments performance was worse for the sequences produced by the naturally fast talkers than for those produced by the naturally slow talkers. This finding suggests that the extent to which allophonic variation contributes to the identification of word boundaries may depend on the rate at which the speech was produced.
Immunomodulation by Melatonin: Its Significance for Seasonally Occurring Diseases
Authors: Srinivasan Venkataramanujam , Spence D. Warren , Trakht Ilya , Pandi-Perumal Seithikurippu R. , Cardinali Daniel P. , Maestroni Georges J.
Published: August 2008

Melatonin is not only synthesized by the pineal gland but also in many other organs and tissues of the body, particularly by lymphoid organs such as the bone marrow, thymus and lymphocytes. Melatonin participates in various functions of the body, among which its immunomodulatory role has assumed considerable significance in recent years. Melatonin has been shown to be involved in the regulation of both cellular and humoral immunity. Melatonin not only stimulates the production of natural killer cells, monocytes and leukocytes, but also alters the balance of T helper (Th)-1 and Th-2 cells mainly towards Th-1 responses and increases the production of relevant cytokines such as interleukin (IL)-2, IL-6, IL-12 and interferon-γ. The regulatory function of melatonin on immune mechanisms is seasonally dependent. This fact may in part account for the cyclic pattern of symptom expression shown by certain infectious diseases, which become more pronounced at particular times of the year. Moreover, melatonin-induced seasonal changes in immune function have also been implicated in the pathogenesis of seasonal affective disorder and rheumatoid arthritis. The clinical significance of the seasonally changing immunomodulatory role of melatonin is discussed in this review.