bluuebunny/crossref_metadata_2025 huggingface dataset:
Production of silver‐doped analcime by isomorphous substitution technique
Authors: Kwakye‐Awuah B. , Radecka I. , Kenward M. A. , Williams C. D.
Published: April 2008

BACKGROUND: Metal‐exchanged zeolites have been reported to have significant limitations on cayalytic activity, such as counterbalancing the negative framework charges and limitation of active space. Alternative methods of incorporating silver ions into the framework of zeolites are therefore necessary. This paper reports on a technique for producing silver doped analcime by isomorphous substitution of silver ion into the framework of analcime. The amount of aluminium in the gel composition was reduced by a factor of 5%, 10% and 20% and an equivalent amount of silver was added to the gel and treated in a conventional manner for zeolite crystallisation. Some of the aluminium in the reaction gel was replaced with the silver. The silver‐doped analcime samples where characterised by X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐rays (EDX), Fourier transform infrared (FTIR) spectroscopy and inductively coupled plasma‐atomic emission spectroscopy (ICP‐AES) analysis.

RESULTS: The amount of silver ions loaded for each reduction of aluminium as determined by EDX were found to be (w/w) 0.29%, 1.41% and 2.10%, respectively. XRD pattern SEM images of the silver‐doped analcime showed the presence of zeolite P in addition to analcime.

CONCLUSION: Silver‐doped analcime was successfully produced with different silver loadings and may exhibit higher anti‐microbial activities than silver‐exchanged counterparts. Copyright © 2008 Society of Chemical Industry
Effect of loading rate on TOC consumption efficiency in a sulfate reducing process: sulfide effect in batch culture
Authors: García‐Saucedo Citlali , Fernández Francisco J. , Buitrón Germán , Cuervo‐López Flor M. , Gómez Jorge
Published: April 2008

BACKGROUND: The sulfate reducing process (SRP) was analyzed in order to identify factors that diminish the effectiveness of the SRP during wastewater treatment. The effect of different sulfate loading rates (SLR, 290 to 981 mg SO4‐S L−1d−1) and lactate at a stoichiometric C/S ratio of 0.75 on SRP was studied in an upflow anaerobic sludge blanket (UASB) reactor. The effect of sulfide concentration (0 to 200 mg sulfide‐S L−1) on SRP in batch culture was evaluated.

RESULTS: When the SLR was increased, the total organic carbon (TOC) and sulfate consumption efficiencies decreased from 93% ± 3 to 66% ± 2 and 60% ± 5 to 45% ± 4, respectively. Acetate and propionate were accumulated. Microbial analysis showed the presence of microorganisms related with the SRP, fermentation and methanogenesis. In batch culture, when lactate and sulfate were present, SRP and fermentation were observed. When sulfide was added only SRP was observed. At concentrations higher than 150 mg sulfide‐S L−1 the efficiencies, yields and specific consumption rates (q) decreased.

CONCLUSION: Based on the sulfide‐S/volatile suspended solid ratio, it was found that the decrease in efficiency and accumulation of acetate and propionate in the UASB reactor was not related to sulfide inhibition but to the q of acetate and propionate, which were up to 11 times lower than lactate. Copyright © 2008 Society of Chemical Industry
Depolymerization of poly(ethylene terephthalate) in dilute aqueous ammonia solution under hydrothermal conditions
Authors: Zenda Kentaro , Funazukuri Toshitaka
Published: April 2008

BACKGROUND: Various methods, such as glycolysis, methanolysis, and hydrolysis with supercritical water, have been investigated for chemical recycling of poly(ethylene terephthalate) (PET), which is used in large quantities for beverage containers. However, a more effective process is needed.

RESULTS: PET was depolymerized in aqueous ammonia in a batch reactor and a semi‐batch reactor over a temperature range 463 to 573 K, at a pressure 10 MPa, and with up to 3 mol L−1 ammonia. Total organic carbon in the product solution and yields of the major products such as terephthalic acid (TPA) and ethylene glycol (EG) were measured. The PET pellet sample was thoroughly solubilized in aqueous ammonia under hydrothermal conditions, and more than 90% of the initial PET samples were recovered as TPA + EG on a carbon weight basis. Depolymerization rates were represented by 2/3‐order reaction kinetics with respect to unreacted PET, where the reaction took place on the PET pellet surface. The rate increased slightly with increasing ammonia concentration.

CONCLUSION: Ammonia was effective for depolymerization of PET, allowing the recovery of TPA and EG under hydrothermal conditions. Copyright © 2008 Society of Chemical Industry
Exact boundary observability for nonautonomous first‐order quasilinear hyperbolic systems
Authors: Guo Lina , Wang Zhiqiang
Published: April 2008

By means of the theory on the semiglobal C1 solution to the mixed initial‐boundary value problem for first‐order quasilinear hyperbolic systems, we establish the local exact boundary observability for general nonautonomous first‐order quasilinear hyperbolic systems without zero eigenvalues and reveal the essential difference between nonautonomous hyperbolic systems and autonomous hyperbolic systems. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and complete assignment of the 1H and 13C NMR signals of some oxopyrancoumarin and oxofuropyrancoumarin derivatives
Authors: Quezada Elías , Delogu Giovanna , Viña Dolores , Santana Lourdes , Picciau Carmen , Podda Gianni , Uriarte Eugenio
Published: April 2008

The synthesis of four pyranocoumarins starting from phloroglucinol and the complete 1H and 13C NMR assignment of seven pyranocoumarins has been performed using 1D and 2D NMR techniques including COSY, HMQC and HMBC experiments. Copyright © 2008 John Wiley & Sons, Ltd.
A 13C solid‐state NMR analysis of steroid compounds
Authors: Yang Jen‐Hsien , Ho Yu , Tzou Der‐Lii M.
Published: April 2008

13C CP/MAS solid‐state NMR spectroscopy has been utilized to analyze six steroid compounds, namely testosterone (Tes), hydrocortisone (Cor), trans‐dehydroandrosterone (Adr), prednisolone (Prd), prednisone (Pre) and estradiol (Est). Among them, Tes displays a doublet pattern for all residues, whereas Prd, Pre and Est, exhibit exclusively singlets. For Cor and Adr, the 13C spectra contain both doublet and singlet patterns. The 13C doublet signal, with splittings of 0.2–1.5 ppm, are ascribed to local differences in the ring conformations associated with polymorphism. We have assigned all of the 13C resonances to the different residues in these steroid compounds on the basis of solution NMR data. The C‐7, C‐8, C‐10, C‐15 and C‐16 residues of Tes, Cor and Adr consistently give rise to singlets or doublets with splittings of less than 0.5 ppm, indicating similar local conformations. Accompanying hydration and dehydration processes, a reversible phase transformation between δ‐ and α‐crystal forms has been observed in Tes, corresponding to singlet and doublet 13C patterns, respectively. To further characterize the ring conformations in the α‐form, we have successfully extracted chemical shift tensor elements for the 13C doublets. It is demonstrated that 13C solid‐state NMR spectroscopy provides a reliable and sensitive means of characterizing polymorphism in steroids. Copyright © 2008 John Wiley & Sons, Ltd.
Expression of short‐form oncostatin M receptor as a decoy receptor in lung adenocarcinomas
Authors: Chen DR , Chu C‐Y , Chen C‐Y , Yang H‐C , Chiang Y‐Y , Lin T‐Y , Chiang I‐P , Chuang D‐Y , Yu C‐C , Chow K‐C
Published: April 2008

Oncostatin M (OSM) is a member of the interleukin‐6 (IL‐6) family of cytokines, and binds to the OSM receptor (OSMR) to inhibit cancer growth. Four forms of OSMR have been identified: leukemia inhibitory factor receptor (LIFR), OSMRβ, short‐form OSMR (OSMRs) and soluble OSMR (sOSMR). In this study, we examined the type and expression of OSMR in lung adenocarcinomas (LADCs). Expression of OSMR was determined by reverse transcription–polymerase chain reaction (RT–PCR), immunoblotting, immunohistochemistry and confocal immunofluorescent microscopy (CIM). Our results showed that, among the four forms of OSMR, OSMRs was mainly expressed in LADC, and expression level of OSMRs correlated with patient survival. CIM revealed that OSMRs was localized on the cell membrane of LADC cell lines in vitro. OSMRs acts as a decoy receptor by reducing the inhibitory effect of OSM on cell growth. Decrease in OSMRs expression by siRNA increased cell sensitivity to OSM, and ectopic expression of OSMRs reduced cell sensitivity to OSM. These results suggest that expression of OSMRs, which operates as a decoy receptor for OSM, is correlated with disease progression and adverse prognosis in patients with LADC. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Infection by Helicobacter pylori expressing the BabA adhesin is influenced by the secretor phenotype
Authors: Azevedo M , Eriksson S , Mendes N , Serpa J , Figueiredo C , Resende LP , Ruvoën‐Clouet N , Haas R , Borén T , Le Pendu J , David L
Published: April 2008

Helicobacter pylori (Hp) infects half the world's population and causes diverse gastric lesions, from gastritis to gastric cancer. Our aim was to evaluate the significance of secretor and Lewis status in infection and in vitro adherence by Hp expressing BabA adhesin. We enrolled 304 Hp‐infected individuals from Northern Portugal. Gastric biopsies, blood and saliva were collected. Polymerase chain reaction (PCR) and immunofluorescence were used to detect BabA+ Hp in gastric biopsies. In vitro adherence by a BabA expressing Hp strain to gastric biopsies was performed. Secretor status was identified by Ulex, a lectin that recognizes secretor‐dependent glycan structures in saliva and in gastric mucosa, and by Lewisa/b antibodies, and indirectly by identification of an inactivating mutation in the FUT2 gene (G428A). BabA status of infecting Hp was associated with CagA and VacAs1 (p < 0.05), intercellular localization of Hp (p < 0.01) and the presence of intestinal metaplasia (p < 0.05) and degenerative alterations (p < 0.005) in the biopsies. BabA was associated (p < 0.05) with Ulex staining of gastric biopsies and, although not significantly, to absence of homozygosity for FUT2 G428A inactivating polymorphism. In vitro Hp adherence was higher in cases wild‐type or heterozygous for FUT2 G428A mutation (p < 0.0001), cases staining for Ulex (p < 0.0001) and a−b+ and a−b− secretor phenotypes (p < 0.001). In conclusion, BabA+ Hp infection/adhesion is secretor‐dependent and associated with the severity of gastric lesions. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Snail‐associated epithelial–mesenchymal transition promotes oesophageal squamous cell carcinoma motility and progression
Authors: Usami Y , Satake S , Nakayama F , Matsumoto M , Ohnuma K , Komori T , Semba S , Ito A , Yokozaki H
Published: April 2008

The essential contribution of the epithelial–mesenchymal transition (EMT) to carcinoma progression is the loss of their epithelial characters, gain of mesenchymal marker expression, acquisition of migration, invasive activity and capability to pass through the basement membrane. In this study, we aimed to clarify the role of EMT regulator Snail, a zinc finger transcription factor, in human oesophageal squamous cell carcinoma (OESCC). Most OESCC cell lines expressed epithelial cell–cell adhesion molecules such as E‐cadherin and claudin‐1 and ‐7; however, TE‐8 (Snail‐positive) cells expressed mesenchymal marker vimentin but not E‐cadherin and claudins. Transduction of ectopic Snail in TE‐15 (Snail‐negative) cells diminished expression of these epithelial adhesion molecules with promotion of cell migration, invasion and proliferation as well as the shift from cobblestone‐like appearance to spindle morphology. In OESCC tissue samples, immunohistochemical analyses revealed that the nuclear Snail expression at the invasive front was correlated with the high levels of vimentin expression (p = 0.0061), which was conversely associated with reduced expressions of E‐cadherin (p = 0.023), claudin‐1 (p = 0.0246) and claudin‐7 (p = 0.0161). Interestingly, elevated Snail expression at the invasive front of the OESCC was associated with higher incidence of lymphatic (p = 0.0143) and venous vessels invasion (p = 0.0029), lymph node metastasis (p = 0.0074) and clinicopathological tumour stage (p = 0.0057). According to the expressions of epithelial and mesenchymal markers, the tumours were subclassified into three groups, the epithelial‐type OESCC and the complete or incomplete EMT‐type OESCCs. Snail‐positive tumours were frequently categorized into the complete‐ or incomplete‐type EMT phenotypes. Our present results suggest the significance of Snail‐associated EMT in the progression of OESCC. Snail‐induced EMT at the invasive front of the OESCC can be a novel marker for the prediction of metastasis. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
New Technologies and Instruction
Authors: Clement Frank
Published: April 2008

Digits form the language of the ubiquitous computer from the multi million dollar main frame to the digital watch. Digitization permits the storage and manipulation of such information as text, graphics, music, voice and television pictures. Digital information can be transmitted over vast distances with tremendous accuracy. In summary, the most important aspect of digitalized information is that it has opened up an information era that will put to shame anything that was done before. Understanding the digitalizing process is not necessary to its use, but it may help in understanding the vast changes that are coming to our working, learning and living environment.
Functionalization of carbon nanofibers (CNFs) through atom transfer radical polymerization for the preparation of poly(tert‐butyl acrylate)/CNF materials: Spectroscopic, thermal, morphological, and physical characterizations
Authors: Ghislandi Marcos , de A. Prado Luis Antonio Sanchez , de la Vega Oyerviedes Alejandra , Wittich Hans , Schulte Karl , Barros‐Timmons Ana
Published: April 2008

Vapor‐grown carbon nanofibers (CNFs) were oxidized and functionalized for atom transfer radical polymerization (ATRP) of tert‐butyl acrylate (t‐BA) from the surface of the CNFs. The materials were characterized by solubility tests, Fourier‐transform infrared (FTIR) spectroscopy, Raman spectroscopy, thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and scanning electron microscopy. The FTIR and electron microscopy results suggest that ATRP process was successfully used to graft poly(tert‐butyl acrylate) (poly(t‐BA)) chains from the surface of the fibers. Raman results strongly indicate the partial degradation of the graphitic layer of CNFs because of the chemical treatments. TGA results suggest that the presence of poly(t‐BA) leads to a decrease of the initial degradation temperature of the fibers. XRD and electron microscopy results indicate that the microstructure of fibers was not destroyed because of the oxidation and functionalization processes. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3326–3335, 2008
Synthesis and chiroptical properties of poly (p‐phenylenevinylene‐alt‐m‐phenylenevinylene) bearing (−)‐trans‐myrtanoxyl groups on the p‐phenylene rings
Authors: Li Xiangfeng , Li Chusheng , Yan Jiaguo , Lu Jiang , Liang Hui
Published: April 2008

Chiral poly(p‐phenylenevinylene‐alt‐m‐phenylenevinylene)s bearing (−)‐trans‐myrtanoxyl groups on the p‐phenylene rings were synthesized by Wittig's reaction and Heck's reaction, respectively, namely Myr‐PMPV‐w and Myr‐PMPV‐h correspondingly. The chiroptical properties of the polymers were investigated in chlorobenzene solution by circular dichroism. The results showed that both Myr‐PMPV‐w and Myr‐PMPV‐h showed no Cotton effect due to their irregular molecular structure. By the treatment with I2, most of the cis‐vinylene linkages in Myr‐PMPV‐w were converted to trans‐vinylenes, consequently, the structure of Myr‐PMPV‐w became much more regular, and the resulting polymer (iso‐Myr‐PMPV‐w) showed strong bisignate Cotton effects in the π–π* transition. Compared to its analogous poly(p‐phenylenevinylene) (PPV) (iso‐Myr‐PPV‐w), iso‐Myr‐PMPV‐w showed much stronger Cotton effect, its maximum g value was about one order of magnitude higher than that of iso‐Myr‐PPV‐w under the same conditions. With increasing concentration and decreasing temperature, the gmax value of iso‐Myr‐PMPV‐w increased, and the maximum absorption was slightly blue‐shifted, but the shape and range of absorption curves did not changed significantly, and no clear isosbestic point could be observed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3336–3343, 2008
Frontal polymerization of diurethane diacrylates
Authors: Mariani Alberto , Fiori Stefano , Bidali Simone , Alzari Valeria , Malucelli Giulio
Published: April 2008

This work deals with the preparation of poly(urethane acrylates) by using two different polymerization techniques. Namely, the classical batch procedure has been compared with frontal polymerization (FP). A thorough study on the effect of initiator type, concentration, and on the velocity of the front and its maximum temperature has been carried out. Moreover, two different synthetic ways have been studied: the one step poly(urethane acrylate) preparation starting directly from 1,6 diisocyanato hexane and 2‐hydroxyethyl acrylate, and the two step procedure consisting of the synthesis of the corresponding diurethane diacrylate and of its subsequent polymerization. The first method has the advantage of being faster but some caution is necessary due to the excessive heat that is generated if the reaction conditions are not properly chosen. The second approach requires a further step but has the advantage of being more controlled. DSC analysis did not show any significant difference by comparing the thermal properties of the materials obtained by the two techniques (batch and FP). However, since FP runs are very easy and fast to be performed, FP should be seriously taken into proper account when these materials have to be prepared. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3344–3352, 2008
Influence of nitroxide structure on polystyrene brushes “grafted‐from” silicon wafers
Authors: Ostaci Roxana‐Viorela , Celle Caroline , Seytre Gérard , Beyou Emmanuel , Chapel Jean‐Paul , Drockenmuller Eric
Published: April 2008

Alkoxyamine derivatives based on 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO), N‐tert‐butyl‐N‐(1‐diethylphosphono‐(2,2‐dimethylpropyl)) nitroxide (SG1) and N‐tert‐butyl‐N‐(2‐methyl‐1‐phenylpropyl) nitroxide (TIPNO) containing a C11 hydrophobic spacer and a reactive triethoxysilyl polar head, were synthesized and anchored to silicon wafers by the Langmuir–Blodgett reactive deposition technique at surface pressures ranging from 15 to 32 mN/m. Polystyrene brushes (Mn ∼ 8500–66,400 g/mol) were grown from the alkoxyamine functionalized silicon wafers by nitroxide mediated radical polymerization and characterized by ellipsometry and water contact angle measurements. The main parameters influencing the grafting density and the degree of stretching of the brushes are the nitroxide polarity and, therefore, the behavior of the corresponding alkoxyamines at the air/water interface of the Langmuir–Blodgett trough. Depending on the alkoxyamine chemical structure and the surface pressure during Langmuir–Blodgett deposition, polystyrene brushes with grafting densities of 0.3–1.0 chains/nm2 and stretching values of 40–70% were obtained. Regarding alkoxyamines deposited at high surface pressures, size exclusion chromatography experiments performed on both cleaved polystyrene brushes and chains simultaneously grown in the bulk revealed that the polymerization degree of the bulk and surface chains are significantly different, suggesting that steric constrains affect the polymerization kinetics occurring at the silicon surface. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3367–3374, 2008
A new photoiniferter/RAFT agent for ambient temperature rapid and well‐controlled radical polymerization
Authors: Tasdelen Mehmet Atilla , Durmaz Yasemin Yuksel , Karagoz Bunyamin , Bicak Niyazi , Yagci Yusuf
Published: April 2008

Phenacyl morpholine‐4‐dithiocarbamate is synthesized and characterized. Its capability to act as both a photoiniferter and reversible addition fragmentation chain transfer agent for the polymerization of styrene is examined. Polymerization carried out in bulk under ultra violet irradiation at above 300 nm at room temperature shows controlled free radical polymerization characteristics up to 50% conversions and produces well‐defined polymers with molecular weights close to those predicted from theory and relatively narrow poyldispersities (Mw/Mn ∼ 1.30). End group determination and block copolymerization with methyl acrylate suggest that morpholino dithiocarbamate groups were attained at the end of the polymer. Photolysis and polymerization studies revealed that polymerization proceeds via both reversible termination and RAFT mechanisms. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3387–3395, 2008
Transition metal complexes of a cyclic pseudo hexapeptide: synthesis, complex formation and catalytic activities
Authors: Ngyen Huong , Orlamuender Marit , Pretzel David , Agricola Inge , Sternberg Ulrich , Reissmann Siegmund
Published: April 2008

To contribute to a better understanding of metalloenzymes, we studied ion selectivity, complex formation tendencies and catalytic activities of linear and cyclic pseudopeptides. In this contribution, a linear and cyclic pseudo hexapeptide is described. The complex with transition metal ions and the sequence were designed using the programme COSMOS. Different routes of solid‐phase synthesis were performed and compared using anchoring by C‐terminus or a His side chain, using preformed pseudodipeptide building units or formation of N‐functionalized peptide bond during stepwise assembly. The different strategies were compared regarding cyclization tendency, yield and purity. Side‐chain anchoring to solid support favours the cyclization but leads to the formation of difficult to separate dioxopiperazine. Both routes require preformed building units. Complex‐formation tendencies and selectivity for certain bivalent transition metal ions were experimentally estimated and compared to ones predicted theoretically. CD measurements indicate conformational changes by complex formation with different metal ions. Catalytic activities on oxidation of catechol and hydrolysis of bis‐phosphate esters by some metal complexes of linear and cyclic peptide show only low catalytic activities compared to other model peptides and related metalloenzymes. The preference of the cyclic peptide for complexation of Ni2+ corresponds well to the predictions of COSMOS‐NMR force field calculations. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
First‐principles study on electronic structure of fullerene polymers
Authors: Kitajima H. , Egami Y. , Nakayama H. , Hirose K. , Ono T.
Published: April 2008

The geometrical structures and electronic properties of P66 fullerene‐polymer sheets areinvestigated using semiempirical tight‐binding calculations and first‐principles calculationsbased on the density functional theory. Our results indicate that the sheet becomes metallic when the [2 + 2] cycloadditional bond between the two neighboring P66 polymer chains is stretched. We also examine the electronic structure of the sheet sandwiched between electrodes and found that the sheet exhibits metallic behavior. Copyright © 2008 John Wiley & Sons, Ltd.
Parametric robust inferences for correlated ordinal data
Authors: Tsou Tsung‐Shan , Shen Chung‐Wei
Published: April 2008

The aim of this article is to provide asymptotically valid likelihood inferences about regression parameters for correlated ordinal response variables. The legitimacy of this novel approach requires no knowledge of the underlying joint distributions so long as their second moments exist. The efficacy of the proposed parametric approach is demonstrated via simulations and the analyses of two real data sets. Copyright © 2008 John Wiley & Sons, Ltd.
Analyzing sequentially randomized trials based on causal effect models for realistic individualized treatment rules
Authors: Bembom Oliver , van der Laan Mark J.
Published: April 2008

In this paper, we argue that causal effect models for realistic individualized treatment rules represent an attractive tool for analyzing sequentially randomized trials. Unlike a number of methods proposed previously, this approach does not rely on the assumption that intermediate outcomes are discrete or that models for the distributions of these intermediate outcomes given the observed past are correctly specified. In addition, it generalizes the methodology for performing pairwise comparisons between individualized treatment rules by allowing the user to posit a marginal structural model for all candidate treatment rules simultaneously. This is particularly useful if the number of such rules is large, in which case an approach based on individual pairwise comparisons would be likely to suffer from too much sampling variability to provide an informative answer. In addition, such causal effect models represent an interesting alternative to methods previously proposed for selecting an optimal individualized treatment rule in that they immediately give the user a sense of how the optimal outcome is estimated to change in the neighborhood of the identified optimum. We discuss an inverse‐probability‐of‐treatment‐weighted (IPTW) estimator for these causal effect models, which is straightforward to implement using standard statistical software, and develop an approach for constructing valid asymptotic confidence intervals based on the influence curve of this estimator. The methodology is illustrated in two simulation studies that are intended to mimic an HIV/AIDS trial. Copyright © 2008 John Wiley & Sons, Ltd.
Identifying significant covariates for anti‐HIV treatment response: Mechanism‐based differential equation models and empirical semiparametric regression models
Authors: Huang Yangxin , Liang Hua , Wu Hulin
Published: April 2008

In this paper, the mechanism‐based ordinary differential equation (ODE) model and the flexible semiparametric regression model are employed to identify the significant covariates for antiretroviral response in AIDS clinical trials. We consider the treatment effect as a function of three factors (or covariates) including pharmacokinetics, drug adherence and susceptibility. Both clinical and simulated data examples are given to illustrate these two different kinds of modeling approaches. We found that the ODE model is more powerful to model the mechanism‐based nonlinear relationship between treatment effects and virological response biomarkers. The ODE model is also better in identifying the significant factors for virological response, although it is slightly liberal and there is a trend to include more factors (or covariates) in the model. The semiparametric mixed‐effects regression model is very flexible to fit the virological response data, but it is too liberal to identify correct factors for the virological response; sometimes it may miss the correct factors. The ODE model is also biologically justifiable and good for predictions and simulations for various biological scenarios. The limitations of the ODE models include the high cost of computation and the requirement of biological assumptions that sometimes may not be easy to validate. The methodologies reviewed in this paper are also generally applicable to studies of other viruses such as hepatitis B virus or hepatitis C virus. Copyright © 2008 John Wiley & Sons, Ltd.
A distribution‐free test of constant mean in linear mixed effects models
Authors: Lim Johan , Wang Xinlei , Lee Seokho , Jung Sin‐Ho
Published: April 2008

We propose a distribution‐free procedure, an analogy of the DIP test in non‐parametric regression, to test whether the means of responses are constant over time in repeated measures data. Unlike the existing tests, the proposed procedure requires very minimal assumptions to the distributions of both random effects and errors. We study the asymptotic reference distribution of the test statistic analytically and propose a permutation procedure to approximate the finite‐sample reference distribution. The size and power of the proposed test are illustrated and compared with competitors through several simulation studies. We find that it performs well for data of small sizes, regardless of model specification. Finally, we apply our test to a data example to compare the effect of fatigue in two different methods used for cardiopulmonary resuscitation. Copyright © 2008 John Wiley & Sons, Ltd.
Modeling heaping in self‐reported cigarette counts
Authors: Wang Hao , Heitjan Daniel F.
Published: April 2008

In studies of smoking behavior, some subjects report exact cigarette counts, whereas others report rounded‐off counts, particularly multiples of 20, 10 or 5. This form of data reporting error, known as heaping, can bias the estimation of parameters of interest such as mean cigarette consumption. We present a model to describe heaped count data from a randomized trial of bupropion treatment for smoking cessation. The model posits that the reported cigarette count is a deterministic function of an underlying precise cigarette count variable and a heaping behavior variable, both of which are at best partially observed. To account for an excess of zeros, as would likely occur in a smoking cessation study where some subjects successfully quit, we model the underlying count variable with zero‐inflated count distributions. We study the sensitivity of the inference on smoking cessation by fitting various models that either do or do not account for heaping and zero inflation, comparing the models by means of Bayes factors. Our results suggest that sufficiently rich models for both the underlying distribution and the heaping behavior are indispensable to obtaining a good fit with heaped smoking data. The analyses moreover reveal that bupropion has a significant effect on the fraction abstinent, but not on mean cigarette consumption among the non‐abstinent. Copyright © 2008 John Wiley & Sons, Ltd.
An index approach for the Cox model with left censored covariates
Authors: D'Angelo Gina , Weissfeld Lisa ,   on behalf of the GenIMS Investigators
Published: April 2008

Medical studies frequently collect biological markers in which many subjects have values below the detectable limits of the assay, resulting in heavily censored data. We develop a modification of the Rigobon and Stoker index method for application to a Cox regression model with censored covariates. The index approach is compared with a complete case method and various fill‐in methods. Our simulation results demonstrated that the index approach is an improvement over the other methods. We illustrated the usefulness of this approach with an example for the GenIMS study examining the relationship between two inflammatory markers and survival. Copyright © 2008 John Wiley & Sons, Ltd.
Interval estimation of risk difference for data sampled from clusters
Authors: Paul Sudhir R. , Zaihra Tasneem
Published: April 2008

Risk difference (RD) is an important measure in epidemiological studies where the probability of developing a disease for individuals in an exposed group, for example, is compared with that in a control group. There are varying cluster sizes in each group and the binary responses within each cluster cannot be assumed independent. Under the cluster sampling scenario, Lui (Statistical Estimation of Epidemiological Risk. Wiley: CA, 2004; 7–27) discusses four methods for the construction of a confidence interval for the RD. In this paper we introduce two very simple methods. One method is based on an estimator of the variance of a ratio estimator (Sampling Techniques (3rd edn). Wiley: New York, 1977; 30–67) and the other method is based on a sandwich estimator of the variance of the regression estimator using the generalized estimating equations approach of Zeger and Liang (Biometrics 1986; 42:121–130). These two methods are then compared, by simulation, in terms of maintaining nominal coverage probability and average coverage length, with the four methods discussed by Lui (Statistical Estimation of Epidemiological Risk. Wiley: CA, 2004; 7–27). Simulations show at least as good properties of these two methods as those of the others. The method based on an estimate of the variance of a ratio estimator performs best overall. It involves a very simple variance expression and can be implemented with a very few computer codes. Therefore, it can be considered as an easily implementable alternative. Copyright © 2008 John Wiley & Sons, Ltd.
Confidence intervals for P(Y1>Y2) with normal outcomes in linear models
Authors: Tian Lili
Published: April 2008

Recently, there is an emerging interest in the inference of P(Y1>Y2) where Y1 and Y2 stand for two independent continuous random variables. So far, most of the research in this field focuses on simply comparing two outcomes without adjusting for covariates. This paper mainly presents a large sample approach based on a noncentral t distribution for the confidence interval estimation of P(Y1>Y2) with normal outcomes in linear models. Furthermore, the performance of the proposed large sample approach is compared with that of a generalized variable approach and a bootstrap approach. Simulation studies demonstrate that for small‐to‐medium sample sizes, both the large sample approach and the generalized variable approach provide confidence intervals with satisfying coverage probabilities whereas the bootstrap approach can be slightly liberal for certain scenarios. The proposed approaches are applied to three real‐life data sets. Copyright © 2008 John Wiley & Sons, Ltd.
Cultural distance, investment flow, and control in cross‐border cooperation
Authors: Lee Seung‐Hyun , Shenkar Oded , Li Jiatao
Published: April 2008

Previous research analyzing the impact of cultural distance on joint venture negotiations has often confounded firm and environment effects. To decouple these effects, the cross‐border cooperation preferences of small and medium‐sized Korean firms were studied, considering simultaneously firms involved in inward and outward investment ventures. While cultural distance showed no significant relationship with the degree of control sought over the cooperative ventures, cultural distance was significantly related with a preference for ventures in domestic or foreign markets. The impact of cultural distance was found to be greater in inward investment than in outward investment. Copyright © 2008 John Wiley & Sons, Ltd.
Achieving accurate and context‐sensitive timing for code optimization
Authors: Whaley R. Clint , Castaldo Anthony M.
Published: April 2008

Key computational kernels must run near their peak efficiency for most high‐performance computing (HPC) applications. Getting this level of efficiency has always required extensive tuning of the kernel on a particular platform of interest. The success or failure of an optimization is usually measured by invoking a timer. Understanding how to build reliable and context‐sensitive timers is one of the most neglected areas in HPC, and this results in a host of HPC software that looks good when reported in the papers, but delivers only a fraction of the reported performance when used by actual HPC applications. In this paper, we motivate the importance of timer design and then discuss the techniques and methodologies we have developed in order to accurately time HPC kernel routines for our well‐known empirical tuning framework, ATLAS. Copyright © 2008 John Wiley & Sons, Ltd.
Diagnosis and management of genitourinary prolapse
Authors: Adekanmi Olugbenga A. , Freeman Robert M.
Published: April 2008

Female genitourinary prolapse, or pelvic organ prolapse, is a common gynaecological problem, often associated with symptoms that do not correlate with the site and degree of prolapse. Although surgery is the mainstay of treatment, the patient should first be offered conservative treatment options. Adequate counselling is essential, as there is a risk of recurrence after surgery. Copyright © 2008 Wiley Interface Ltd
Squamous cell carcinoma in a patient with lichen sclerosus
Authors: Babu Chitra S. , Morgan Emile
Published: April 2008

The authors present the case of a man with squamous cell carcinoma arising from lichen sclerosus. This case highlights the importance of close follow‐up in all cases of lichen sclerosus in view of the small risk of malignant transformation. Copyright © 2008 Wiley Interface Ltd
Lubrication improvement and friction reduction of DLC‐coated sliding surfaces by in‐process structuring and post polishing
Authors: Andersson P. , Koskinen J. , Varjus S. , Kolehmainen J. , Tervakangas S. , Buss W.
Published: April 2008

The paper describes an experimental investigation on the influence of the surface roughness of diamond‐like hard carbon (DLC) coatings on the friction and wear in sliding contact against steel under conditions of starving lubrication. Experimental studies employed a reciprocating ball‐on‐flat tribometer in two different modes of operation. The study showed a micro‐lubrication effect in terms of lubrication assistance achieved by microscopic cavities in the topography of a DLC coating and good sliding behaviour even in the case of starving oil lubrication. Post‐process polishing of the coated surfaces was adopted for eliminating unnecessary friction losses due to asperity interactions and micro‐abrasive wear. Copyright © 2008 John Wiley & Sons, Ltd.
Tribological testing of coated surfaces
Authors: Koskinen Jari
Published: April 2008

This special issue is dedicated to the tribology of coated surfaces. It comprises five papers which treat the issue from different viewpoints. They cover, e.g. the selection and design of tribological experiment and analyses of coatings tribology in lubricated contacts. Copyright © 2008 John Wiley & Sons, Ltd.
Chronic kidney disease after liver, cardiac, lung, heart–lung, and hematopoietic stem cell transplant
Authors: Hingorani Sangeeta
Published: April 2008

Patient survival after cardiac, liver, and hematopoietic stem cell transplant (HSCT) is improving; however, this survival is limited by substantial pretransplant and treatment-related toxicities. A major cause of morbidity and mortality after transplant is chronic kidney disease (CKD). Although the majority of CKD after transplant is attributed to the use of calcineurin inhibitors, various other conditions such as thrombotic microangiopathy, nephrotic syndrome, and focal segmental glomerulosclerosis have been described. Though the immunosuppression used for each of the transplant types, cardiac, liver and HSCT is similar, the risk factors for developing CKD and the CKD severity described in patients after transplant vary. As the indications for transplant and the long-term survival improves for these children, so will the burden of CKD. Nephrologists should be involved early in the pretransplant workup of these patients. Transplant physicians and nephrologists will need to work together to identify those patients at risk of developing CKD early to prevent its development and progression to end-stage renal disease.
Effect of interannual variations in sea‐surface temperature on egg‐laying parameters of black‐tailed gulls (Larus crassirostris) at Teuri Island, Japan
Authors: Tomita Naoki , Niizuma Yasuaki , Takagi Masaoki , Ito Motohiro , Watanuki Yutaka
Published: April 2008

Sea‐surface temperature (SST) directly and indirectly affects the distribution and abundance of prey species for seabirds, so we expect variation in SST to be associated with variation in seabird life history traits. In black‐tailed gulls (Larus crassirostris) at Teuri Island in northern Hokkaido, Japan, we investigated the diet of the gulls prior to egg laying in 2004 and 2005, and examined the influences of SST in March or April, when the gulls congregate in the colony, on egg‐laying parameters using 13 years of data (1992–2004). The gulls fed on krill (Thysanoessa inermis) and fish prior to the egg laying. Mean first egg dates and clutch sizes were significantly and quadratically related to SST anomalies in March, but were not influenced by SST anomalies in April. There was no significant effect of SSTs in either March or April on egg volume. Sea‐surface temperature anomalies in March of the years of early laying (−1 to 1°C) were higher than those in 2001 (−2.2°C), but lower than those in 1992 (+1.2°C) and 2004 (+1.1°C). Thysanoessa inermis congregates to spawn at the sea surface, when SSTs rise 3−4°C. Thus, a mismatch between food availability and the timing of egg production in the gulls could have occurred in these 3 years. This study suggests that SST fluctuations prior to laying are important in breeding success of black‐tailed gulls.
Percutaneous Pinning of Fifth Carpal–Metacarpal Fracture–Dislocations: An Alternative Pin Trajectory
Authors: Saing Minn H. , Lee Sue Y. , Raphael James S.
Published: April 2008

Traditional management of unstable fourth and fifth carpal–metacarpal (CMC) fracture–dislocations (fx–dislocs) of the hand includes closed reduction and percutaneous pinning (CRPP) versus open reduction internal fixation (ORIF). Traditional trajectory of pin placement is toward the base of the hook of the hamate. Our case series of CMC fx–dislocs treated with this trajectory led to the development of ulnar deep motor branch symptoms (sxs). We attempt to propose an alternative trajectory that could lower the chance of iatrogenic injury. Five fresh frozen cadaveric specimens underwent percutaneous pinning of the fifth CMC joint using fluoroscopic guidance. Each cadaver was dissected, and the proximity of the deep motor branch of the ulnar nerve was measured in relation to a pin that penetrated the volar cortex. Our results confirm the close proximity of the deep motor branch of the ulnar nerve to the volar cortex of the hamate and demonstrate the potential for iatrogenic injury during CRPP of the fifth CMC fx–dislocs, especially with penetration of the volar cortex. By demonstrating the close proximity of the deep motor branch to the volar cortex of the hamate in cadavers, we highlight the potential for iatrogenic injury with CRPP of CMC fx–dislocs as seen in our case series. We recommend a more midaxial starting point on the proximal metacarpal with a trajectory aimed at the midbody of the hamate to prevent penetration of the hamate volar cortex and limit the chances of iatrogenic injury.
The Triumph of the Egg
Authors: Freidberg Susanne E.
Published: April 2008

On 11 December 1912, Philadelphians encountered an extraordinary sight in their city's streets. Groups of prominent society women—“famous beauties and matrons … known all over the continent”—were selling eggs all over town. These eggs differed from those we buy today in that most had been in storage since April. Housewives nonetheless flocked to buy them, because they cost only 24 cents a dozen, much less than other April eggs. The sellers, themselves members of the Housekeepers' League, claimed they would not make money off the “hen fruit” that they had bought by the carload, but neither would they lose it. Rather, they aimed to break a commercial corner on eggs that, they claimed, fostered unfair and deceptive trade practices. In particular, they wanted to stop merchants from charging “strictly fresh” prices for what were in fact refrigerated eggs.
Cars, the Customs Service, and Sumptuary Rule in Neoliberal Ghana
Authors: Chalfin Brenda
Published: April 2008

This essay probes the role of commodities in the crafting of state power, working from the vantage point of contemporary Ghana, a polity at once post-socialist and staunchly neoliberal, least-industrialized and highly cosmopolitan. Among the many commodities which Ghana's citizens and state bodies identify with and rely upon, cars are of critical significance. In what follows, I explore the raft of interventions surrounding car importation and allocation imposed by Ghana's Customs Service, and the resulting public critique, in an effort to capture the shifting contours of state authority in the context of an electoral and economic transition spurred by neoliberal reform.
Conceptualizing Gods through Statues: A Study of Personification and Localization in Taiwan
Authors: Lin Wei-Ping
Published: April 2008

When I first started fieldwork in Wannian, a village in southwestern Taiwan, I stayed in the village leader's house. At this early stage of the fieldwork, my relationship with the villagers was no more than polite and formal. One afternoon, I heard villagers talking in low and urgent voices about their temple's god statue. When I approached, they fell silent. No matter how I tried to question them about what had happened, they would tell me nothing. In the following days the village atmosphere became ponderous and oppressive, and I felt my presence there becoming increasingly awkward. Thinking that leaving for a while might provide a relief for both the villagers and me, I moved to a neighboring village. Since it was only one kilometer away, the wind brought the sound of the Wannian village loudspeaker. Though they had lowered the volume, I could vaguely hear announcements of preparations for upcoming ceremonies of worship. After a month, I moved back to Wannian, but only several years later did I understand what had happened.
Affect, Memory, and Materiality: A Review Essay on Archival Mediation
Authors: Rao Anupama
Published: April 2008

InSociety Must Be Defended, Michel Foucault characterizes the permanent, conflictual relationship that exists “between the two groups that constitute the social body and shape the State [as] in fact one of … permanent warfare” (2003: 88). Foucault argues that acknowledging that “race wars” constitute the substructure of the state enables a new conception of power, one that is simultaneously implicated in knowledge regarding the source of that power: re-conceptualizing the bases of power also demands a shift in knowledge practices. This problem (of power/knowledge) was administrative/managerial from the start: it constituted the conditions of possibility for the exercise of sovereign power, and was itself sovereign-like. “The administration allows the king to rule the country at will, and subject to no restrictions. And conversely, the administration rules the king thanks to the quality and nature of the knowledge it forces upon him” (ibid.: 128–29). Foucault asserts that historical knowledge is produced at precisely this juncture, as a form of counter-knowledge that is the outgrowth of a race war or class war, in which the nobility seek to defend society—their society—from new challengers, “the people,” for example, as well as from the sovereign himself. Thus, modern history germinated as a form of knowledge against absolutist sovereign power, but it was grafted onto the edifice of the state to buttress the sovereign's threatened legitimacy. Thus, “From 1760 onward we see the emergence of institutions that were roughly the equivalent of a ministry of history” (2003: 130 ff).
Authors: Scott James C.
Published: April 2008

In Hagen's Community in the Balance, one finds both a fine and deeply empathetic ethnography of a marginal hill-people in Eastern Indonesia and a subtle meditation on the fragility of this, and indeed any, human community.
Authors: Pearl Laura
Published: April 2008

Appadurai's Fear of Small Numbers is an important contribution to the study of one of the most harmful aspects of modernity, violence against minorities. Although anthropology—a discipline prolific on the topics of ethnicity, nationalism, and religious identity, as well as modernity—is well situated to offer insight into this problem, few anthropologists have addressed it in general terms. We can thus view Appadurai's monograph as the beginning of an important conversation, and like many seminal works, his contains both monumental insights and notable missteps.