bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Japanese encephalitis virus share the same cellular receptor with other mosquito-borne flaviviruses on the C6/36 mosquito cells?
Authors: Ren Junping , Ding Tianbing , Zhang Wei , Song Jianhua , Ma Wenyu
Published: September 2007

Japanese encephalitis virus (JEV) is a member of mosquito-borne Flaviviridae. To date, the mechanisms of the early events of JEV infection remain poorly understood, and the cellular receptors are unidentified. There are evidences that the structure of the virus attachment proteins (VAP), envelope glycoprotein of mosquito-borne flaviviruses is very similar, and the vector-virus interaction of mosquito-borne flaviviruses is also very similar. Based on the studies previously demonstrated that the similar molecules present on the mosquito cells involved in the uptake process of JEV, West Nile virus (WNV) and Dengue virus (DV), it is proposed that the same receptor molecules for mosquito-borne flaviviruses (JEV, WNV and DV) may present on the surface of C6/36 mosquito cells. By co-immunoprecipitation assay, we investigated a 74-KDa protein on the C6/36 cells binds JEV, and the mass spectrometry results indicated it may be heat shock cognate protein 70(HSC70) from Aedes aegypti. Based upon some other viruses use of heat shock protein 70 (HSP70) family proteins as cell receptors, its possible HSC70's involvement in the fusion of the JEV E protein with the C6/36 cells membrane, and known form of cation channels in the interaction of HSC70 with the lipid bilayer, it will further be proposed that HSC70 as a penetration receptor mediates JEV entry into C6/36 cells.
Discovery of herpesviruses in multi-infected primates using locked nucleic acids (LNA) and a bigenic PCR approach
Authors: Prepens Sandra , Kreuzer Karl-Anton , Leendertz Fabian , Nitsche Andreas , Ehlers Bernhard
Published: September 2007

Targeting the highly conserved herpes DNA polymerase (DPOL) gene with PCR using panherpes degenerate primers is a powerful tool to universally detect unknown herpesviruses. However, vertebrate hosts are often infected with more than one herpesvirus in the same tissue, and pan-herpes DPOL PCR often favors the amplification of one viral sequence at the expense of the others. Here we present two different technical approaches that overcome this obstacle: (i) Pan-herpes DPOL PCR is carried out in the presence of an oligonucleotide substituted with locked nucleic acids (LNA).This suppresses the amplification of a specific herpesvirus DPOL sequence by a factor of approximately 1000, thereby enabling the amplification of a second, different DPOL sequence. (ii) The less conserved glycoprotein B (gB) gene is targeted with several sets of degenerate primers that are restricted to gB genes of different herpesvirus subfamilies or genera. These techniques enable the amplification of gB and DPOL sequences of multiple viruses from a single specimen. The partial gB and DPOL sequences can be connected by long-distance PCR, producing final contiguous sequences of approximately 3.5 kbp. Such sequences include parts of two genes and therefore allow for a robust phylogenetic analysis. To illustrate this principle, six novel herpesviruses of the genera Rhadinovirus, Lymphocryptovirus and Cytomegalovirus were discovered in multi-infected samples of non-human primates and phylogenetically characterized.
Progressive loss of CD3 expression after HTLV-I infection results from chromatin remodeling affecting all the CD3 genes and persists despite early viral genes silencing
Authors: Akl Haidar , Badran Bassam , Dobirta Gratiela , Manfouo-Foutsop Germain , Moschitta Maria , Merimi Makram , Burny Arsène , Martiat Philippe , Willard-Gallo Karen E
Published: September 2007

Background

HTLV-I infected CD4+T-cells lines usually progress towards a CD3-or CD3lowphenotype. In this paper, we studied expression, kinetics, chromatin remodeling of the CD3 gene at different time-points post HTLV-I infection.

Results

The onset of this phenomenon coincided with a decrease ofCD3γ followed by the subsequent progressive reduction inCD3δ, thenCD3ε andCD3ζ mRNA. Transient transfection experiments showed that theCD3γ promoter was still active in CD3-HTLV-I infected cells demonstrating that adequate amounts of the required transcription factors were available. We next looked at whether epigenetic mechanisms could be responsible for this progressive decrease in CD3 expression using DNase I hypersensitivity (DHS) experiments examining theCD3γ andCD3δ promoters and theCD3δ enhancer. In uninfected and cells immediately post-infection all three DHS sites were open, then the CD3γ promoter became non accessible, and this was followed by a sequential closure of all the DHS sites corresponding to all three transcriptional control regions. Furthermore, a continuous decrease ofin vivobound transcription initiation factors to theCD3γ promoter was observed after silencing of the viral genome. Coincidently, cells with a lower expression of CD3 grew more rapidly.

Conclusion

We conclude that HTLV-I infection initiates a process leading to a complete loss of CD3 membrane expression by an epigenetic mechanism which continues along time, despite an early silencing of the viral genome. Whether CD3 progressive loss is an epiphenomenon or a causal event in the process of eventual malignant transformation remains to be investigated.
Retroperitoneal haemorrhage in renal angiomyolipoma causing hepatic functional decompensation: a case report
Authors: Wajed Julekha R , Taylor-Robinson Simon D , Jackson James E , Stamp Gordon WH
Published: September 2007

Renal angiomyolipomata usually present as incidental findings on routine imaging, but rarely they may give rise to significant haemorrhage. If bleeding occurs, first-line treatment is currently angiography with selective embolisation. Prophylactic embolisation may be considered in some cases, depending on lesion size and patient co-morbidities.

We present a case of retroperitoneal bleeding from a renal angiomyolipoma in a patient with known cirrhosis of the liver, which caused acute deterioration of liver function and consequent hepatic encephalopathy. Selective embolisation of the lesion was performed with a good subsequent outcome. Such functional hepatic decompensation has not previously been reported in this context and we suggest the use of prophylactic embolisation for incidental renal angiomyolipomata, regardless of size, in all patients with chronic liver disease to prevent this potentially life-threatening complication.
Antipolymer antibody in Italian fibromyalgic patients
Authors: Bazzichi Laura , Giacomelli Camillo , De Feo Francesca , Giuliano Tiziana , Rossi Alessandra , Doveri Marica , Tani Chiara , Wilson Russell B , Bombardieri Stefano
Published: September 2007

The objectives of the present study were to evaluate the presence of antipolymer antibody (APA) seropositivity in 285 Italian patients affected by primary fibromyalgia (FM) and to verify whether APA levels correlate with disease severity and with cytokine levels.

APA levels were determined on serum samples by an indirect ELISA kit that detects IgG APA. Cytokines (IL-1, IL-6, IL-8, IL-10 and TNFα) were measured by ELISA in plasma. The impact of FM on the quality of life was estimated using the Fibromyalgia Impact Questionnaire, while pain severity was evaluated using a visual analogic scale. Patients were also characterized by the presence of tiredness, stiffness, nonrestorative sleep, anxiety, depression, tension headache, irritable bowel syndrome, temporomandibular dysfunction and Raynaud's phenomena.

Using a cut-off value of 30 U, APA-positive values were detected in 60 FM patients (21.05%) and in 15 healthy control individuals (15.00%) without significant differences among their levels or the percentage of seropositivity. FM patients with moderate and severe symptoms had slightly higher APA levels with respect to patients with mild symptoms. APA-seropositive patients exhibited significant correlations between APA levels and the Fibromyalgia Impact Questionnaire estimate (P = 0.042), tiredness (P = 0.003) and IL-1 levels (P = 0.0072).

In conclusion, APA cannot be considered a marker of disease in Italian FM patients. The presence of APA, however, might permit the identification of a subset of FM patients with more severe symptoms and of patients who may respond differently to different therapeutic strategies.
Tissue Doppler in critical illness: a retrospective cohort study
Authors: Sturgess David J , Marwick Thomas H , Joyce Christopher J , Jones Mark , Venkatesh Bala
Published: September 2007

Background

There is a paucity of published data on tissue Doppler imaging (TDI) in the critically ill. In a critically ill cohort, we studied the distribution of TDI and its correlation with other echocardiographic indices of preload. To aid hypothesis generation and sample size calculation, associations between echocardiographic variables, including the ratio of peak early diastolic transmitral velocity (E) to peak early diastolic mitral annular velocity (E'), and mortality were also explored.

Methods

This retrospective study was performed in a combined medical/surgical, tertiary referral intensive care unit. Over a 2-year period, 94 consecutive patients who underwent transthoracic echocardiography with E/E' measurement were studied.

Results

Mean Acute Physiology and Chronic Health Evaluation III score was 72 ± 25. Echocardiography was performed 5 ± 6 days after intensive care unit admission. TDI variables exhibited a wide range (E' 4.7–18.2 cm/s and E/E' 3.3 to 27.2). E' below 9.6 cm/s was observed in 63 patients (rate of myocardial relaxation below lower 95% confidence limit of normal individuals). Fourteen patients had E/E' above 15 (evidence of raised left ventricular filling pressure). E/E' correlated with left atrial area (r = 0.27, P = 0.01) but not inferior vena cava diameter (r = 0.16, P = 0.21) or left ventricular end-diastolic volume (r = 0.16, P = 0.14). In this cohort, increased left ventricular end-systolic volume, but not E/E', appeared to be an independent predictor (odds ratio 2.1, P = 0.007) of 28-day mortality (31%; n = 29).

Conclusion

There was a wide range of TDI values. TDI evidence of diastolic dysfunction was common. E/E' did not correlate strongly with other echocardiographic indices of preload. Further evaluation of echocardiographic variables, particularly left ventricular end-systolic volume, for risk stratification in the critically ill appears warranted.
Cost-effectiveness of activated protein C in real-life clinical practice
Authors: Dhainaut Jean-François , Payet Stéphanie , Vallet Benoit , França Lionel Riou , Annane Djillali , Bollaert Pierre-Edouard , Tulzo Yves Le , Runge Isabelle , Malledant Yannick , Guidet Bertrand , Le Lay Katell , Launois Robert ,   the PREMISS Study Group
Published: September 2007

Background

Recombinant human activated protein C (rhAPC) has been reported to be cost-effective in severely ill septic patients in studies using data from a pivotal randomized trial. We evaluated the cost-effectiveness of rhAPC in patients with severe sepsis and multiple organ failure in real-life intensive care practice.

Methods

We conducted a prospective observational study involving adult patients recruited before and after licensure of rhAPC in France. Inclusion criteria were applied according to the label approved in Europe. The expected recruitment bias was controlled by building a sample of patients matched for propensity score. Complete hospitalization costs were quantified using a regression equation involving intensive care units variables. rhAPC acquisition costs were added, assuming that all costs associated with rhAPC were already included in the equation. Cost comparisons were conducted using the nonparametric bootstrap method. Cost-effectiveness quadrants and acceptability curves were used to assess uncertainty of the cost-effectiveness ratio.

Results

In the initial cohort (n = 1096), post-license patients were younger, had less co-morbid conditions and had failure of more organs than did pre-license patients (for all: P < 0.0001). In the matched sample (n = 840) the mean age was 62.4 ± 14.9 years, Simplified Acute Physiology Score II was 56.7 ± 18.5, and the number of organ failures was 3.20 ± 0.83. When rhAPC was used, 28-day mortality tended to be reduced (34.1% post-license versus 37.4% pre-license, P = 0.34), bleeding events were more frequent (21.7% versus 13.6%, P = 0.002) and hospital costs were higher (€47,870 versus €36,717, P < 0.05). The incremental cost-effectiveness ratios gained were as follows: €20,278 per life-year gained and €33,797 per quality-adjusted life-year gained. There was a 74.5% probability that rhAPC would be cost-effective if there were willingness to pay €50,000 per life-year gained. The probability was 64.3% if there were willingness to pay €50,000 per quality-adjusted life-year gained.

Conclusion

This study, conducted in matched patient populations, demonstrated that in real-life clinical practice the probability that rhAPC will be cost-effective if one is willing to pay €50,000 per life-year gained is 74.5%.
Drosophila Niemann-Pick Type C-2genes control sterol homeostasis and steroid biosynthesis: a model of human neurodegenerative disease
Authors: Huang Xun , Warren James T. , Buchanan JoAnn , Gilbert Lawrence I. , Scott Matthew P.
Published: September 2007

Mutations in either of the two human Niemann-Pick type C (NPC) genes, NPC1 and NPC2, cause a fatal neurodegenerative disease associated with abnormal cholesterol accumulation in cells. npc1a,the Drosophila NPC1 ortholog, regulates sterol homeostasis and is essential for molting hormone (20-hydroxyecdysone; 20E) biosynthesis. While only one npc2 gene is present in yeast, worm, mouse and human genomes, a family of eight npc2 genes (npc2a-h) exists in Drosophila. Among the encoded proteins, Npc2a has the broadest expression pattern and is most similar in sequence to vertebrate Npc2. Mutation of npc2a results in abnormal sterol distribution in many cells, as in Drosophila npc1a or mammalian NPC mutant cells. In contrast to the ecdysteroid-deficient, larval-lethal phenotype of npc1a mutants, npc2a mutants are viable and fertile with relatively normal ecdysteroid level. Mutants in npc2b, another npc2 gene, are also viable and fertile, with no significant sterol distribution abnormality. However, npc2a; npc2b double mutants are not viable but can be rescued by feeding the mutants with 20E or cholesterol,the basic precursor of 20E. We conclude that npc2a functions redundantly with npc2b in regulating sterol homeostasis and ecdysteroid biosynthesis, probably by controlling the availability of sterol substrate. Moreover, npc2a; npc2b double mutants undergo apoptotic neurodegeneration, thus constituting a new fly model of human neurodegenerative disease.
Long form of latent TGF-β binding protein 1 (Ltbp1L) is essential for cardiac outflow tract septation and remodeling
Authors: Todorovic Vesna , Frendewey David , Gutstein David E. , Chen Yan , Freyer Laina , Finnegan Erin , Liu Fangyu , Murphy Andrew , Valenzuela David , Yancopoulos George , Rifkin Daniel B.
Published: September 2007

Latent TGF-β binding protein 1 (LTBP1) is a member of the LTBP/fibrillin family of extracellular proteins. Due to the usage of different promoters, LTBP1 exists in two major forms, long (L) and short (S), each expressed in a temporally and spatially unique fashion. Both LTBP1 molecules covalently interact with latent TGF-β and regulate its function,presumably via interaction with the extracellular matrix (ECM). To explore the in vivo role of Ltbp1 in mouse development, at the time when only the L isoform is expressed, we mutated the Ltbp1L locus by gene targeting. Ltbp1L-null animals die shortly after birth from defects in heart development, consisting of the improper septation of the cardiac outflow tract(OFT) and remodeling of the associated vessels. These cardiac anomalies present as persistent truncus arteriosus (PTA) and interrupted aortic arch(IAA), which are associated with the faulty function of cardiac neural crest cells (CNCCs). The lack of Ltbp1L in the ECM of the septating OFT and associated vessels results in altered gene expression and function of CNCCs and decreased Tgf-β activity in the OFT. This phenotype reveals a crucial role for Ltbp1L and matrix as extracellular regulators of Tgf-β activity in heart organogenesis.
Regulation of transcription of the RNA splicing factor hSlu7 by Elk-1 and Sp1 affects alternative splicing
Authors: Alberstein Moti , Amit Maayan , Vaknin Keren , O'Donnell Amanda , Farhy Chen , Lerenthal Yaniv , Shomron Noam , Shaham Ohad , Sharrocks Andrew D. , Ashery-Padan Ruth , Ast Gil
Published: September 2007

Alternative splicing plays a major role in transcriptome diversity and plasticity, but it is largely unknown how tissue-specific and embryogenesis-specific alternative splicing is regulated. The highly conserved splicing factor Slu7 is involved in 3′ splice site selection and also regulates alternative splicing. We show that Slu7 has a unique spatial pattern of expression among human and mouse embryonic and adult tissues. We identified several functional Ets binding sites and GC-boxes in the human Slu7 (hSlu7) promoter region. The Ets and GC-box binding transcription factors, Elk-1 and Sp1, respectively, exerted opposite effects on hSlu7 transcription: Sp1 protein enhances and Elk-1 protein represses transcription in a dose-dependent manner. Sp1 protein bound to the hSlu7 promoter in vivo, and depletion of Sp1 by RNA interference (RNAi) repressed hSlu7 expression. Elk-1 protein bound to the hSlu7 promoter in vivo, and depletion of Elk-1 by RNAi caused an increase in the endogenous level of hSlu7 mRNA. Further, depletion of either Sp1 or Elk-1 affected alternative splicing. Our results provide indications of a complex transcription regulation mechanism that controls the spatial and temporal expression of Slu7, presumably allowing regulation of tissue-specific alternative splicing events.
Chemical modification resolves the asymmetry of siRNA strand degradation in human blood serum
Authors: Hoerter John A.H. , Walter Nils G.
Published: September 2007

Small interfering (si)RNAs have recently been used to therapeutically silence genes in vivo after intravenous systemic delivery. Further progress in the development of siRNA therapeutics will in part rely on tailoring site-specific chemical modifications of siRNAs to optimize their pharmacokinetic properties. Advances are particularly needed to improve the nucleolytic stability of these double-stranded RNA drugs in vivo and suppress adverse off-target gene silencing effects. Here we demonstrate that specific chemical 2′-O-methylation, which has already been shown to ameliorate the omnipresent off-target toxicity of siRNAs, selectively protects the particularly vulnerable 5′-end of the guide strand against exonucleolytic degradation in human blood serum. Specific chemical modification thus resolves the asymmetric degradation of the guide and passenger strands, which is inherent to the thermodynamic asymmetry of the siRNA termini as required for proper utilization of the guide strand in RNA interference.
p53–RNA interactions: New clues in an old mystery
Authors: Riley Kasandra J.-L. , Maher L. James
Published: September 2007

The p53 tumor suppressor protein is typically considered to be a sequence-specific DNA-binding transcription factor. However, reports over the last 15 years have described RNA binding by p53 in a variety of contexts, suggesting the possibility of new p53 functions. It is clear that p53–RNA interactions are mediated by a nucleic acid-binding domain of p53 independent of the sequence-specific core domain responsible for DNA recognition. Reports disagree on several aspects of the putative RNA interaction, including sequence specificity and biological relevance. Here we review the history and recent advances in the study of p53–RNA interactions. We argue that p53–RNA interactions are sequence nonspecific and depend on incomplete post-translational modification of the p53 C-terminal domain when the protein is expressed in heterologous systems. It is unknown what fraction of p53 protein exists in a state competent for RNA binding in vivo. Thus, potential physiological roles of p53–RNA interactions remain mysterious.
Phenylalanyl-tRNA synthetase editing defects result in efficient mistranslation of phenylalanine codons as tyrosine
Authors: Ling Jiqiang , Yadavalli Srujana S. , Ibba Michael
Published: September 2007

Translational quality control is monitored at several steps, including substrate selection by aminoacyl-tRNA synthetases (aaRSs), and discrimination of aminoacyl-tRNAs by elongation factor Tu (EF-Tu) and the ribosome. Phenylalanyl-tRNA synthetase (PheRS) misactivates Tyr but is able to correct the mistake using a proofreading activity named editing. Previously we found that overproduction of editing-defective PheRS resulted in Tyr incorporation at Phe-encoded positions in vivo, although the misreading efficiency could not be estimated. This raised the question as to whether or not EF-Tu and the ribosome provide further proofreading mechanisms to prevent mistranslation of Phe codons by Tyr. Here we show that, after evading editing by PheRS, Tyr-tRNAPhe is recognized by EF-Tu as efficiently as the cognate Phe-tRNAPhe. Kinetic decoding studies using full-length Tyr-tRNAPhe and Phe-tRNAPhe, as well as a poly(U)-directed polyTyr/polyPhe synthesis assay, indicate that the ribosome lacks discrimination between Tyr-tRNAPhe and Phe-tRNAPhe. Taken together, these data suggest that PheRS editing is the major proofreading step that prevents infiltration of Tyr into Phe codons during translation.
Minimally Infeasible Set-Partitioning Problems with Balanced Constraints
Authors: Conforti Michele , Summa Marco Di , Zambelli Giacomo
Published: September 2007

We study properties of systems of linear constraints that are minimally infeasible with respect to some subset S of constraints (i.e., systems that are infeasible but that become feasible on removal of any constraint in S). We then apply these results and a theorem of Conforti, Cornuéjols, Kapoor, and Vušković to a class of 0, 1 matrices, for which the linear relaxation of the set-partitioning polytope LSP(A)= {x∣Ax = 1, x ≥ 0} is integral. In this way, we obtain combinatorial properties of those matrices in the class that are minimal (w.r.t. taking row submatrices) with the property that the set-partitioning polytope associated with them is infeasible.
An Infinite-Dimensional Linear Programming Algorithm for Deterministic Semi-Markov Decision Processes on Borel Spaces
Authors: Klabjan Diego , Adelman Daniel
Published: September 2007

We devise an algorithm for solving the infinite-dimensional linear programs that arise from general deterministic semi-Markov decision processes on Borel spaces. The algorithm constructs a sequence of approximate primal-dual solutions that converge to an optimal one. The innovative idea is to approximate the dual solution with continuous piecewise linear ridge functions that naturally represent functions defined on a high-dimensional domain as linear combinations of functions defined on only a single dimension. This approximation gives rise to a primal/dual pair of semi-infinite programs, for which we show strong duality. In addition, we prove various properties of the underlying ridge functions.
Hilbert-Valued Perturbed Subgradient Algorithms
Authors: Barty Kengy , Roy Jean-Sébastien , Strugarek Cyrille
Published: September 2007

We propose a Hilbert-valued perturbed subgradient algorithm with stochastic noises, and we provide a convergence proof for this algorithm under classical assumptions on the descent direction and new assumptions on the stochastic noises. Instead of requiring the stochastic noises to correspond to martingale increments, we only require these noises to be asymptotically so. Furthermore, the variance of these noises is allowed to grow infinitely under the control of a decreasing sequence linked with the subgradient stepsizes. This algorithm can be used to solve stochastic closed-loop control problems without any a priori discretization of the uncertainty, such as linear decision rules or tree representations. It can also be used as a way to perform stochastic dynamic programming without state-space discretization or a priori functional bases (i.e., approximate dynamic programming). Both problems arise frequently—for example, in power systems scheduling or option pricing. This article focuses on the theorical foundations of the algorithm, and gives references to detailed practical experimentations.
Stochastic Search in a Forest Revisited
Authors: Sethuraman Jay , Tsitsiklis John N.
Published: September 2007

We consider a generalization of the model of stochastic search in an out-forest, introduced and studied by E. V. Denardo, U. G. Rothblum, L. Van der Heyden. 2004. Index policies for stochastic search in a forest with an application to R&D project management. Math. Oper. Res. 29(1) 162–181. We provide a simpler proof of the optimality of index-based policies.
Convergence Analysis of Sample Average Approximation Methods for a Class of Stochastic Mathematical Programs with Equality Constraints
Authors: Xu Huifu , Meng Fanwen
Published: September 2007

In this paper we discuss the sample average approximation (SAA) method for a class of stochastic programs with nonsmooth equality constraints. We derive a uniform Strong Law of Large Numbers for random compact set-valued mappings and use it to investigate the convergence of Karush-Kuhn-Tucker points of SAA programs as the sample size increases. We also study the exponential convergence of global minimizers of the SAA problems to their counterparts of the true problem. The convergence analysis is extended to a smoothed SAA program. Finally, we apply the established results to a class of stochastic mathematical programs with complementarity constraints and report some preliminary numerical test results.
Lagrangian Relaxation via Ballstep Subgradient Methods
Authors: Kiwiel Krzysztof C. , Larsson Torbjörn , Lindberg P. O.
Published: September 2007

We exhibit useful properties of ballstep subgradient methods for convex optimization using level controls for estimating the optimal value. Augmented with simple averaging schemes, they asymptotically find objective and constraint subgradients involved in optimality conditions. When applied to Lagrangian relaxation of convex programs, they find both primal and dual solutions, and have practicable stopping criteria. Up until now, similar results have only been known for proximal bundle methods, and for subgradient methods with divergent series stepsizes, whose convergence can be slow. Encouraging numerical results are presented for large-scale nonlinear multicommodity network flow problems.
A Large Deviation Principle for Join the Shortest Queue
Authors: Puhalskii Anatolii A. , Vladimirov Alexander A.
Published: September 2007

We consider a join-the-shortest-queue model, which is as follows. There are K single FIFO servers and M arrival processes. The customers from a given arrival process can be served only by the servers from a certain subset of all servers. The actual destination is the server with the smallest weighted queue length. The arrival processes are assumed to obey a large deviation principle while service is exponential. A large deviation principle is established for the queue-length process. The action functional is expressed in terms of solutions to mathematical programming problems. The large deviation limit point is identified as a weak solution to a system of idempotent equations. Uniqueness of the weak solution follows by trajectorial uniqueness.
Complex Matrix Decomposition and Quadratic Programming
Authors: Huang Yongwei , Zhang Shuzhong
Published: September 2007

This paper studies the possibilities of the linear matrix inequality characterization of the matrix cones formed by nonnegative complex Hermitian quadratic functions over specific domains in the complex space. In its real-case analog, such studies were conducted in Sturm and Zhang [Sturm, J. F., S. Zhang. 2003. On cones of nonnegative quadratic functions. Math. Oper. Res. 28 246–267]. In this paper it is shown that stronger results can be obtained for the complex Hermitian case. In particular, we show that the matrix rank-one decomposition result of Sturm and Zhang [Sturm, J. F., S. Zhang. 2003. On cones of nonnegative quadratic functions. Math. Oper. Res. 28 246–267] can be strengthened for the complex Hermitian matrices. As a consequence, it is possible to characterize several new matrix co-positive cones (over specific domains) by means of linear matrix inequality. As examples of the potential application of the new rank-one decomposition result, we present an upper bound on the lowest rank among all the optimal solutions for a standard complex semidefinite programming (SDP) problem, and offer alternative proofs for a result of Hausdorff [Hausdorff, F. 1919. Der Wertvorrat einer Bilinearform. Mathematische Zeitschrift 3 314–316] and a result of Brickman [Brickman, L. 1961. On the field of values of a matrix. Proc. Amer. Math. Soc. 12 61–66] on the joint numerical range.
Roman Cement Mortars in Europe’s Architectural Heritage of the 19th Century
Authors: Weber J. , Gadermayr N. , Bayer K. , Hughes D. , Kozlowski R. , Stillhammerova M. , Ullrich D. , Vyskocilova R.
Published: September 2007

Natural cements calcined at low temperatures, so-called Roman cements, formed an important binder material in 19th century construction and facade decoration of many European cities and towns. As a rule, Roman cement mortars appear well preserved. In order to understand their range of composition and properties, a number of samples from historic buildings were collected and analyzed. Microscopic techniques including scanning electron microscopy were employed along with the assessment of physico-mechanical properties. The study shows that the most significant feature of Roman cement mortars is a wide range of differently calcined clinker relicts within each mortar. These unreactive particles, classified as being either overfired or underfired, obviously play an important role for the mortar properties. The binder relicts are composed of a number of phases in the system Ca-Si-Al-Fe. C2S and C2AS (gehlenite) are among the most frequent compounds, their grain size and microstructure depending on calcination temperatures. In particular, the clinkers produced at lower temperatures show nonequilibrium features such as solid solution systems and zoning by partial diffusion. The aggregates found in the mortars cover a wide range of mineralogical compositions reflecting local geological conditions. Cast and in situ applied mortars differ in the amount of aggregate, which is generally lower for cast elements. There is no correlation between the amount of inert material and the state of preservation indicated, e.g., by the occurrence of shrinkage cracks. Historic cast mortars show high compressive strengths at comparably low moduli of elasticity. The total porosity is frequently high. This contribution presents the above-mentioned properties and discusses them in terms of the excellent aging performance of the historic Roman cement mortars.
Activated Sludge Inhibition by Chemical Stressors—A Comprehensive Study
Authors: Henriques Inês D. S. , Kelly Richard T. , Dauphinais Jennifer L. , Love Nancy G.
Published: September 2007

The effects of shock loads of 1‐chloro‐2,4‐dinitrobenzene (CDNB); cadmium; 1‐octanol; 2,4‐dinitrophenol (DNP); weakly complexed cyanide; pH 5, 9, and 11; and high ammonia levels on activated sludge biomass growth, respiration rate, flocculation, chemical oxygen demand removal, dewaterability, and settleability were studied. For all chemical shocks, except ammonia and pH, concentrations that caused 15, 25, and 50% respiration inhibition were used to provide a single pulse shock to sequencing batch reactor systems containing a nitrifying or non‐nitrifying biomass. Cadmium and pH 11 shocks were most detrimental to all processes, followed by CDNB. The DNP and cyanide primarily affected respiration, while pH 5, pH 9, octanol, and ammonia did not affect the treatment process to a significant extent. A chemical source–process effect matrix is provided, which we believe will aid in the development of methods that prevent and/or attenuate the effects of toxic shock loads on activated sludge systems.
Effect of Operational Parameters on the Removal of Particulate Chemical Oxygen Demand in the Activated Sludge Process
Authors: Jimenez Jose A. , La Motta Enrique J. , Parker Denny S.
Published: September 2007

The removal of particulate material in the aeration basin of the activated sludge process is mainly attributed to bioflocculation and hydrolysis of particulate substrate. The bioflocculation process in the aeration tank of the activated sludge process occurs only under favorable conditions in the system, and several common operational parameters affect its performance. The principal objective of this research was to observe the effect of mixed liquor suspended solids, solids retention time (SRT), and extracellular polymer substances on the removal of particulate substrate by bioflocculation. A first‐order particulate removal expression, based on flocculation, accurately described the removal rates for supernatant suspended solids and colloidal chemical oxygen demand. Based on the results presented in this investigation, a mixed liquor concentration of approximately 2200 mg/L, an SRT of at least 3 days, and a contact time of 30 minutes are needed for relatively complete removal of the particulate substrate in a plug‐flow reactor.
Hydrogen Production by Anaerobic Microbial Communities Exposed to Repeated Heat Treatments
Authors: Duangmanee T. , Padmasiri S. I. , Simmons J. J. , Raskin L. , Sung S.
Published: September 2007

Biological hydrogen production by anaerobic mixed communities was studied in laboratory‐scale bioreactors using sucrose as the substrate. A bioreactor in which a fraction of the return sludge was exposed to repeated heat treatments performed better than a control bioreactor without repeated heat treatment of return sludge and produced a yield of 2.15 moles of hydrogen per mole of sucrose, with 50% hydrogen in the biogas. Terminal restriction fragment length polymorphism analysis showed that two different Clostridium groups (comprised of one or more species) were dominant during hydrogen production. The relative abundance of two other non‐Clostridium groups increased during periods of decreased hydrogen production. The first group consisted of Bifidobacterium thermophilum, and the second group included one or more of Bacillus, Melissococcus, Spirochaeta, and Spiroplasma spp.
Natural Occurrence of Metallothioneinlike Proteins in Liver Tissues of Four Fish Species from the Northeast Mediterranean Sea
Authors: Atli G. , Canli M.
Published: September 2007

Fish with different ecological needs were captured from the northeast Mediterranean Sea to determine metallothioneinlike proteins in their livers. Heat‐treated liver samples were run on a column packed with Sephadex G‐75 (Sigma, Germany) for subsequent determination of metals, sulfhydryl, and absorbance at 254 and 280 nm. Liver cytosols of Sparus auratus and Mullus barbatus had three heat‐stable protein peaks, whereas Mugil cephalus and Atherina hepsetus had two. The third protein peak, containing metallothioneinlike proteins (5000 to 6000 Da), was present in all fish. Only high‐ and low‐molecular‐weight proteins contained sulfhydryl and metals. Zinc was the most abundant metal in the metallothioneinlike proteins, whereas cadmium and lead were not detected. The differences in the characteristics of metal‐binding proteins among fish indicate that the biological characteristics of fish species should be carefully taken into account concerning natural monitoring studies.
Effect of Cold‐Temperature Shock on Nitrification
Authors: Hwang Jong Hyuk , Oleszkiewicz Jan A.
Published: September 2007

Nitrification is known as the most temperature‐sensitive step among the biological processes in wastewater treatment. The purpose of this study was to investigate the effect of temperature on nitrification, in the case of a sharp decrease of temperature, and to compare this effect with that of a gradual temperature decrease. It was found that a sudden temperature decrease affected nitrification much more than predicted. The immediate decrease of temperature by 10°C led to a 20% larger decrease of specific nitrification rate than predicted by the temperature correction factor of 1.072. The change of nitrification rate resulting from a gradual temperature decrease was modeled correctly with the current default temperature correction factor of 1.072. It was concluded that the correction factor actually can be applied to a gradual temperature‐change situation; however, in the case of a sudden temperature decrease, measures need to be taken to avoid nitrifier washout.
Breakthrough Adsorption Study of Migratory Nickel in Fine‐Grained Soil
Authors: Ghosh S. , Mukherjee S. N. , Kumar Sunil , Chakraborty P. , Fan Maohong
Published: September 2007

The present study was conducted to evaluate the breakthrough curve for nickel adsorption in fine‐grained soil from a nearby ash pond site of a thermal power plant. Nickel was found to be the major polluting solute in the ash sluicing wastewater. The adsorption of nickel by vertical soil column batch test and horizontal migration test was carried out in the laboratory. Field investigation was conducted also, by installing test wells around the ash pond site. Experimental results showed a good adsorptive capacity of soil for nickel ions. The breakthrough curves showed a reasonable fitting with a one‐dimensional mathematical model. The breakthrough curves yielded from field test results showed good agreement with a two‐dimensional mathematical model.
Incomplete Oxidation of Ethylenediaminetetraacetic Acid in Chemical Oxygen Demand Analysis
Authors: Anderson James E. , Mueller Sherry A. , Kim Byung R.
Published: September 2007

Ethylenediaminetetraacetic acid (EDTA) was found to incompletely oxidize in chemical oxygen demand (COD) analysis, leading to incorrect COD values for water samples containing relatively large amounts of EDTA. The degree of oxidation depended on the oxidant used, its concentration, and the length of digestion. The COD concentrations measured using COD vials with a potassium dichromate concentration of 0.10 N (after dilution by sample and sulfuric acid) were near theoretical oxygen demand values. However, COD measured with dichromate concentrations of 0.010 N and 0.0022 N were 30 to 40% lower than theoretical oxygen demand values. Similarly, lower COD values were observed with manganic sulfate as oxidant at 0.011 N. Extended digestion yielded somewhat higher COD values, suggesting incomplete and slower oxidation of EDTA, as a result of lower oxidant concentrations. For wastewater in which EDTA is a large fraction of COD, accurate COD measurement may not be achieved with methods using dichromate concentrations less than 0.1 N.
Investigation of Pathogenic Escherichia coli and Microbial Pathogens in Pulp and Paper Mill Biosolids
Authors: Croteau M. C. , Renner V. E. , Archibald F. , Langlois V. S. , Cahn J. , Ridal J. , Trudeau V. L. , Lean D. R. S.
Published: September 2007

Biosolids produced from pulp and paper mill wastewater treatment have excellent properties as soil conditioners, but often contain high levels of Escherichia coli. E. coli are commonly used as indicators of fecal contamination and health hazard; therefore, their presence in biosolids causes concern and has lead to restrictions in land‐spreading. The objectives of this study were to determine the following: (1) if E. coli from the biosolids of a wastewater‐free pulp and paper mill were enteric pathogens, and (2) if other waterborne microbial pathogens were present. E. coli were screened for heat‐labile and heat‐stable enterotoxin and verocytotoxin virulence genes using a polymerase chain reaction. Ten isolates were also screened for invasion‐associated locus and invasion plasmid antigen H genes. None of the 120 isolates carried these genes. Tests for seven other microbial pathogens were negative. Effluents and biosolids from this mill do not contain common microbial pathogens and are unlikely to pose a health hazard.
Reduction of Photoreactivation with the Combined UV/Peracetic Acid Process or by Delayed Exposure to Visible Light
Authors: Martin Nicolas , Gehr Ronald
Published: September 2007

Photoreactivation of microorganisms following UV inactivation is a well‐known, but complex, phenomenon. It is affected by several factors, including UV fluence, wavelength, light intensity, and exposure time to photoreactivating light. The effect on photoreactivation of a combined peracetic acid (PAA)/UV process has not been investigated. Accordingly, this study compared the degree of photoreactivation, under both sunlight and artificial lights, following UV and combined PAA/UV inactivation of fecal coliforms.    Effluent samples from the Montreal Wastewater Treatment Plant (MWTP) (Quebec, Canada) were exposed, for 3 hours, to both low‐ and high‐intensity artificial lights and sunlight. All resulted in similar photoreactivation levels. However, average photoreactivation for UV‐treated wastewater samples was 1.2 logs, compared with 0.1 log for the combined PAA/UV treatment. Hence, the use of PAA in combination with UV can significantly reduce the potential for photoreactivation.    To simulate the photoreactivation conditions of the MWTP effluent (which passes through a 4‐km outfall tunnel with approximately 3 hours detention time), UV‐treated samples were kept in the dark for 3 hours before photoreactivating light exposure. After this period, photoreactivation levels were close to zero. Hence, the effects of photoreactivation may be diminished by use of a combined disinfection scheme and/or by delaying exposure of the disinfected wastewater to light.
The Dichotomies of Rationalism in 20th‐Century Italian Architecture
Authors: Peckham Andrew
Published: September 2007

The two key moments of Rationalism in Italy ‐ the Gruppo 7 of the 1930s and the Tendenza of the 1960s ‐ stand in counterpoint. The Tendenza espoused a very different ideology to its predecessor and thus remained ambivalent to the earlier legacy. Andrew Peckham reveals how this led to a history of discontinuity and, ultimately, recognition of Rationalism's limitations despite the involvement of influential figures such as Giuseppe Terragni, Aldo Rossi and Giorgio Grassi. Copyright © 2007 John Wiley & Sons, Ltd.
Rationalist Practice
Authors: Dudler Max
Published: September 2007

Max Dudler's buildings, conceived as apparently autonomous and self‐referential objects, nonetheless demonstrate a reciprocal relationship with the city and have, over the past two decades, presented a consistent Rationalist approach. Born in 1949 in Switzerland, Max Dudler studied architecture in Frankfurt/Main and Berlin. From 1981 to 1986 he worked in the office of OM Ungers on the projects for the Frankfurt trade fair, and has run his own practice, with offices in Berlin, Frankfurt and Zurich, since 1992. Copyright © 2007 John Wiley & Sons, Ltd.
Dutch Selected Projects
Authors: Rattray Charles
Published: September 2007

The most recent generation of Dutch Rationalists are as distinctive as they are pragmatic. Charles Rattray describes four projects that are visually imposing in their stringent use of geometries, while also being sophisticated in their development of type, spatial configurations and application of elements. Copyright © 2007 John Wiley & Sons, Ltd.
Foster + Partners' Hearst Tower and Gehry Partners' IAC Building
Authors: Merkel Jayne
Published: September 2007

The two most interesting, talked about new office buildings in New York both have unique angular profiles and unusual shiny surfaces that have irrevocably changed their neighbourhoods. Jayne Merkel takes a peak at the interiors of Norman Foster's triangulated steel‐and‐glass Hearst Tower and Frank Gehry's curvaceous, white‐glass hulk for the IAC/InterActiveCorp. In so doing she sizes up what effect the exotic exteriors have on the spaces where the editors, writers, designers and media executives work. Copyright © 2007 John Wiley & Sons, Ltd.
Why Critical Modernism?
Authors: Jencks Charles
Published: September 2007

In a new edition of a seminal book, Critical Modernism: Where is Post‐Modernism Going? (What is Post‐Modernism? 5th Edition), Charles Jencks argues that social and economic forces have reached a new stage of global civilisation. This promises the onset of a new cultural strain of thought: Critical Modernism. Here he defines and argues for a significant and more analytical mode of perceiving the world in all its complexity. Copyright © 2007 John Wiley & Sons, Ltd.
Hertzian Space: Material Response to Spatial Presence
Authors: Taylor Mark
Published: September 2007

Mark Taylor describes how an interest in the possibilities of generating spaces that fully respond to people's presence and their activities led him and Mark Burry to undertake a project with students at Victoria University Wellington, New Zealand, that spatialises the dynamics of a full body massage. Copyright © 2007 John Wiley & Sons, Ltd.
Soft Mechanical Sensors Through Reverse Actuation in Polypyrrole
Authors: Wu Y. , Alici G. , Madden J. D. W. , Spinks G. M. , Wallace G. G.
Published: September 2007

The phenomenon of voltage generated from a soft sensor using polypyrrole in response to mechanical deformation is described and investigated. The sensor consists of two polypyrrole layers in contact with an electrolyte and operates in bending mode in air. The magnitude and sign of the induced voltage was found to depend on the type of dopant counter‐ions and the nature of the surrounding electrolyte. The mechanical sensor response is shown to be a “reverse actuation”, generating millivolt signals for millimeter sized deflections or ∼ 1000 C m–3 charge for 1 % strain in the polypyrrole layer. A model based on ‘Deformation Induced Ion Flux' has been proposed whereby the strain induced volume change in the polymer produces a shift in the Donnan equilibrium between mobile dopant ions inside the polymer and in the external electrolyte. A simple thermodynamic model provides reasonable estimates of the size of the voltage and charge produced.
A Molecularly Imprinted Copolymer Designed for Enantioselective Recognition of Glutamic Acid
Authors: Ouyang R. , Lei J. , Ju H. , Xue Y.
Published: September 2007

A newly designed molecularly imprinted polymer (MIP) material was developed and successfully used as recognition element to fabricate a capacitive sensor for enantioselective recognition of glutamic acid (Glu). The MIP with a well‐defined structure was synthesized on a gold electrode in one step by electrochemical copolymerization of o‐phenylenediamine (o‐PD) and dopamine (DA) in the presence of template molecule Glu. The resulting MIP material was characterized with a potentiostatic frequency scan method, cyclic voltammetry, capacitance measurements, atomic force microscopy, and X‐ray photoelectron spectroscopy. The structure and recognition behaviour of the copolymer film to template molecule depended on its composition. The optimal composition was at the o‐PD to DA molar ratio of 3:2. With a potentiostatic time scan method the copolymer displayed high enantioselectivity and sensitivity to the stereoselective rebinding of L‐ or D‐Glu to their corresponding artificial receptor due to the exact definition of the imprint cavity. The capacitance response of the sensor for L‐Glu or D‐Glu was proportional to their concentration in the range of 16.7 to 250 μM. The enantiometric selectivity coefficients for L‐Glu and D‐Glu imprinted films against their respective enantiomers are 24 and 15, respectively. The resulting MIP capacitive sensors showed good reproducibility, stability and repeatability. This strategy opened a convenient way for preparation of enantioselective MIPs and recognition of enantiotropic molecules.