bluuebunny/crossref_metadata_2025 huggingface dataset:
unconditional Bases in Banach Spaces of Absolutely p‐Summing Operators
Authors: Schütt I.
Published: May 2007

In the present paper we give conditions for Banach spaces of absolutely p‐summing operators to have unconditional bases. In this case we obtain methods to estimate the πp‐norm. Also we consider spaces of absolutely p‐summing operators with “bad” structure, i.e., without local unconditional structure.
On the Strong Approximation by (C, α)‐Means of Fourier Series
Authors: Łenski Włodzimierz
Published: May 2007

The degree of pointwise approximation in the strong sense of 2π‐periodic functions from Lp (p = (1 + α)−1, α > −1/2) is examined. An answer to the modified version of Leindler's problem [4] is given.
Local and Global Descriptions of Periodic Pseudodifferential Operators
Authors: McLean William
Published: May 2007

Periodic pseudodifferential operators can be defined either globally, via FOURIER series, or else locally, via partitions of unity and FOURIER integrals. Here, it is proved that the two definitions are equivalent.
On Linear Dependence Relations for Integer Translates of Compactly Supported Distributions
Authors: Dahmen Wolfgang , Jia Rong Qing , Micchelli Charles A.
Published: May 2007

A necessary and sufficient condition for the dimension of the space of dependence relations for (multi‐) integer translates of an arbitrary compactly supported distribution in terms of zeros of its Fourier transform is given. We apply this result to obtain necessary and sufficient conditions on an integer matrix X so that the space of dependence relations for the corresponding cube spline C(·|X) is finite dimensional. We are able to describe the explicit form of all dependence relations.
Remarks on M‐Ideals of Compact Operators on X ⊕p X
Authors: Oja Eve , Werner Dirk
Published: May 2007

We characterize those Banach spaces X for which K(X ⊕p X) is an M‐ideal in L(X ⊕p X) by means of a variant of the compact metric approximation property. As a consequence we obtain that such a space X must be hereditarily lp‐rich.
On the Inverse Source Problem for the Newtonian Potential
Authors: Luc Le Trong
Published: May 2007

The paper deals with the inverse source problems for the Newtonian potential in the sense of distribution (generalized functions). The inverse source problem is defined as follows: A domain G is given. To find is a distribution creating the potential which is known outside of the closed domain G. New results can be applied to electronical fields, because the electrical charge is distributed only on the surface of conductor.
On the JACOBIan Varieties of PICARD Curves Defined over Fields of Characteristic p < 0
Authors: Estrada‐Sarlabous J.
Published: May 2007

In this paper we confine ourselves to the study of the Jacobian variety J(C) of a Picard curve C defined over a field K of characteristic p > 0, with the aim to obtain explicit conditions under which the Jacobian variety is ordinary or supersingular, in terms of the Hasse‐Witt matrix of the Picard curve.
Remarks on Complex Interpolation of Some Nonlinear Operators (I)
Authors: Böhm Michael
Published: May 2007

Let Aj, Bj be complex B‐spaces, j = 0, 1, Aθ and Bθ–the complex‐interpolation spaces generated by the couples (A0, A1) and (B0, B1), resp., by CALDERON'S/LIONS'S method. Let T: A0 ∧ A1 → B0 → B1 be an operator satisfying some conditions such as continuity, estimates etc. in terms of the norms of Aj, Bj (j = 0, 1). We consider the question which one of these properties is inherited to T when A0 → A1 and B0 → B1 are equipped with the norm of Aθ and Bθ.
Criteria of Nuclearity of Embedding Operators Acting between BERGMAN Spaces and Weighted LEBESQUE Spaces
Authors: Parfenov O. G.
Published: May 2007

In the paper the criteria of nuclearity of embedding operators acting from BERGMAN space into the space Lq(μ) are established. Some questions related to Pr – summability of these operators are considered. The criteria of nuclearity of embedding operator from Hp into Lq(μ) for some class of measures and p ≧ q are given.
Approximation mittels Linearkombinationen von Fundamentallösungen elliptischer Differentialoperatoren
Authors: Hamann Uwe
Published: May 2007

Let Ω ⊂ Rn be a bounded domain with the smooth boundary Γ, L an elliptic differential operator of order 2m with constant coefficients, E a fundamental solution of L and B = (B1, …, Bm) a normal system of boundary operators on Γ. Furtehr let (yk)Γ1 ⊂ Rn/Ω be a sequence of points and Dj(Γ) (j = 1, …, m) suitable function spaces over Γ (e.g. Cs‐spaces or SOBOLEV spaces).

It is investigated, under which conditions on the sequence (yk)x1 ⊂ Rn/Ω the set
The lymphatics in the pathophysiology of thoracic and abdominal surgical pathology: Immunological consequences and the unexpected role of microsurgery
Authors: Boccardo Francesco , Bellini Carlo , Eretta Costantino , Pertile Davide , Da Rin Elisa , Benatti Emanuela , Campisi Mirko , Talamo Giuseppina , Macciò Alberto , Campisi Corrado , Bonioli Eugenio , Campisi Corradino
Published: May 2007

The authors report their experience in the diagnosis and treatment of lymphatic and chylous disorders in the thoracic and abdominal areas. Sixteen patients (10 adults, 6 children) affected by primary chylous ascites with associated syndromes and consequent immunological incompetence were studied. Diagnostic investigations included abdominal sonography scans, lymphoscintigraphy, and lymphography combined with computed tomography and laparoscopy. Surgical treatment included laparoscopy, drainage of ascites and/or the chylothorax, treatment of abdominal and retroperitoneal chylous leaks, exeresis of lymphodysplastic tissues, ligation of incompetent lymph vessels also by CO2 LASER, and chylo‐venous and lympho‐venous microsurgical shunts. Eleven patients did not have a relapse of the ascites and four patients had a persistence of a small quantity of ascites with no protein imbalance. All patients had an improvement of their immunocompetence. Median follow‐up was 5 years. We demonstrated that the use of microsurgery is remarkably advantageous for performing a causal treatment of the dysfunction. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Effects of hyperbaric oxygen therapy on the rat intestinal mucosa apoptosis caused by ischemia‐reperfusion injury
Authors: Bertoletto Paulo Roberto , Fagundes Djalma José , De Jesus Simões Manuel , Oshima Celina T.F. , De Souza Montero Edna Frasson , Simões Ricardo Santos , Fagundes Anna Tereza Negrini
Published: May 2007

To examine the apoptosis expression in the intestinal mucosa in accordance of different periods of hyperbaric oxygen (HBO) treatment, rats were submitted to 60 min of mesenteric artery and vein ischemia and 60 min of reperfusion occlusion. A group (G‐IR) was the control and HBO was applied in the ischemia (GHBO‐I), reperfusion (GHBO‐R), and ischemia and reperfusion time (GHBO‐IR). After 60 min of reperfusion, samples of small bowel were prepared for immunohistochemical expression of caspase‐3. The expression of caspase‐3 was significantly inferior when HBO was administered in the ischemia (0.16 ± 0.01) in comparison with the control (0.70 ± 0.08), but HBO in the further reperfusion (0.84 ± 0.03) or both ischemia and reperfusion time (0.42 ± 0.05) was significantly worse. There was a connection between HBO, small bowel I/R injury, and mucosa apoptosis. The favorable effect was obtained when HBO was administered early in the ischemia time. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Effect of Baohuoside‐1 aglycone and tacrolimus monotherapy and combination therapy on prevention of acute heart allograft rejection in the rat
Authors: Qi Shijie , Zhao Hong , Ma Anlun , Liu Longshan , Wang Xiang , Xu Dasheng , Lin Geng , Tamura Kouichi , Jiang Hongsi , Daloze Pierre , Chen Huifang
Published: May 2007

Baohuoside‐1 (B‐1), a recently introduced novel immunosuppressant that was proved to be potent in inhibition of T and B cell proliferation and B‐1, also prevents cardiac allograft rejection in rodents. The present study further proved that monotherapy of B‐1's analogue B‐1 aglycone effectively prolongs cardiac allograft survival and combination therapy of B‐1 aglycone with tacrolimus (FK506) produces synergistic effect in prevention acute cardiac allograft rejection in the rat. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Cuff‐glue sutureless microanastomosis
Authors: Galvão Flávio Henrique Ferreira , Bacchella Telesforo , Machado Marcel Cerqueira
Published: May 2007

Hand suture microanastomosis is a difficult procedure. This report describes a simplified microanastomosis using cuff and glue apparatus. Model: Vena cava and intestine of rat were sectioned. The distal margin was introduced into an everted cuff covering the outer wall and fixed to the base of the tube by three stitches. The proximal segment was inserted into the cuff system and an encircling ligature was performed to attach both margins to the cuff. Proximal margin below ligature was pulled up exposing both intimae where glue was deposited. The proximal margin was pulled down, sealing the borders by glue adhesion. Ligatures fixing the system were sectioned and the cuff was removed. Anastomosis acquired a waveform shape, obtaining ideal intima–intima union and improving the healing process. After short training, this anastomosis can be performed within 10 min. This technique avoids cuff foreign body reaction, simplifies microanastomosis research, and may improve glue technology for tissue anastomosis. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Teaching intestinal transplantation in the rat for medical student
Authors: Ferreira Galvão Flávio Henrique , Bacchella Telesforo , Cerqueira Machado Marcel
Published: May 2007

Technical difficulties hamper the widespread use of intestinal transplantation in rats. We evaluated the feasibility in training this microsurgical model for medical students. Thirty eight students were assessed. After information about intestinal transplantation in rats, they spontaneously agreed to be trained for this procedure. The course consisted of 4‐h weekly lessons during 4‐month period. The teaching process includes assessment in four phases: I) conception of intestinal transplantation and rat anatomy; II) basic microsurgery training; III) donor operation; IV) donor/recipient operation. Wistar rats were used as donors and recipients in one‐step small bowel transplantation. All students (100%) reached phase II, seven students (18.42%) reached phase III and two students (5.26%) reached phase IV. Decreased interest about the theme, lack of time and patience, frustration and/or inability were all reasons given by the student that may have contributed to the low rate of success. Medical students achieved a low rate of completion for training in rat intestinal transplantation microsurgical procedures. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Effect of tamoxifen on arterial microvascular anastomosis
Authors: De Pinho Pessoa Breno Bezerra Gomes , Cavalcante Bruno Bezerra Menezes , Maia Munique Pinheiro , Filho Haroldo H. Ribeiro , Koike Marcia Kiyomi , Pinho Pessoa Salustiano Gomes De , Pinheiro Luiz Gonzaga Porto , De Souza Montero Edna Frasson
Published: May 2007

Breast reconstruction after cancer treatment is based on the circulation of pedicle and microvascular flaps. This article aimed to verify the effect of tamoxifen (TMX) pretreatment in arterial anastomosis in rats. Twenty female Wistar rats were equally divided into two groups. TMX (0.3 mg/kg) was administered to the experimental group for 2 weeks orally. After this period, the right femoral artery was sectioned and a terminoterminal anastomosis performed. The same procedure was done in the control group, except that the animals received the vehicle without TMX. One week later, the femoral arteries were inspected for flow through the anastomosis, and the vessel near it was sent to light microscopic examination. It was observed mild vasculite in both groups. The intimal thickness and total vessel wall in the TMX‐treated group was significantly higher. A real thrombotic effect upon the arterial vascular anastomosis was not observed, eventhough, TMX induced intimal hyperplasia. © 2007 Wiley‐Liss, Inc. Microsurgery 2007.
Modified relaxation method for mathematical programs with complementarity constraints
Authors: Lin Gui‐Hua
Published: May 2007

In this paper, we suggest a new relaxation method for solving mathematical programs with complementarity constraints. This method can be regarded as a modification of a method proposed in a recent paper (J. Opt. Theory Appl. 2003; 118:81–116). We show that the main results remain true for the modified method and particularly, some conditions assumed in the previous paper can be removed. Copyright © 2007 John Wiley & Sons, Ltd.
Ultrastructure of canine oocytes during in vivo maturation
Authors: de Lesegno Christine Viaris , Reynaud Karine , Pechoux Christine , Thoumire Sandra , Chastant‐Maillard Sylvie
Published: May 2007

The aim of the present study was to describe the canine oocyte ultrastructural modifications during in vivo maturation, with precise reference to the timing of the LH surge and of ovulation. Twenty‐five bitches were ovariectomized at specific stages between the onset of proestrus and the fifth day post‐ovulation: 65 oocytes were observed by transmission electron microscopy (TEM), either before the LH surge (n = 10), between the LH surge and ovulation (n = 12) or after ovulation (n = 43). Prior to the LH surge, the oocyte nucleus had already begun its displacement to the vicinity of the oolemma and reticulated nucleoli were infrequent. The cytoplasm showed signs of immaturity (few organelles preferentially located in the cortical zone, “mitochondrial cloud”, scarce cortical granules). The LH surge was immediately followed by cumulus expansion but the ovulation occurred 2 days later. Retraction of the transzonal projections and the meiotic resumption occurred after another 3 days (5 days after the LH peak). The ovulation was then followed by gradual cytoplasmic modifications. Nucleoli re‐assumed a reticulated aspect around 24 hr post‐ovulation. From 48 hr post‐ovulation mitochondria and SER were very numerous and evenly distributed. In conclusion canine oocyte maturation began prior to the LH surge and no cytoplasmic or nuclear modifications followed immediately the LH surge and ovulation. This study suggests that two distinct signals are needed for the final in vivo maturation: one prior to the LH surge (to induce maturation) and another one, around 3 days post‐ovulation (to induce meiotic resumption). Mol. Reprod. Dev. 75: 115–125, 2008. © 2007 Wiley‐Liss, Inc.
Locating a cycle in a transportation or a telecommunications network
Authors: Laporte Gilbert , Martín Inmaculada Rodríguez
Published: May 2007

Several problems arising in transportation and telecommunications can be cast in terms of optimally locating a cycle in a graph. This paper proposes a classification of cycle location problems under two main headings. In Hamiltonian problems, all vertices of the graph must belong to the cycle. The most important cases are the traveling salesman problem (TSP), the TSP with precedence constraints, the clustered TSP, the TSP with backhauls, the TSP with time windows, several classes of pickup and delivery problems, and stochastic TSPs. In non‐Hamiltonian problems, only a subset of vertices must be visited. These problems include the generalized TSP, the covering tour problem, the median cycle and ring star problems, and several cycle location problems with revenues. These problems are modeled within a unified framework and algorithmic strategies are provided, together with computational results. Several applications are also described. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 50(1), 92–108 2007
Eulerian formulation using stabilized finite element method for large deformation solid dynamics
Authors: Okazawa S. , Kashiyama K. , Kaneko Y.
Published: May 2007

This paper describes an Eulerian formulation for large deformation solid dynamics. In the present Eulerian approach, an advective equation is solved using the Stream‐Upwind/Petrov–Galerkin finite element method. The Eulerian finite element method is applied to path‐dependent solid analyses such as impact bar and ductile necking problems. These computational results using the Eulerian finite element method are compared with the results obtained from using the Lagrangian finite element method and an Eulerian formulation based on a finite difference method. Copyright © 2007 John Wiley & Sons, Ltd.
Scaling, sensitivity and stability in the numerical solution of quadratic eigenvalue problems
Authors: Higham Nicholas J. , Mackey D. Steven , Tisseur Françoise , Garvey Seamus D.
Published: May 2007

The most common way of solving the quadratic eigenvalue problem (QEP) (λ2 M + λD + K)x = 0 is to convert it into a linear problem (λX + Y)z = 0 of twice the dimension and solve the linear problem by the QZ algorithm or a Krylov method. In doing so, it is important to understand the influence of the linearization process on the accuracy and stability of the computed solution. We discuss these issues for three particular linearizations: the standard companion linearization and two linearizations that preserve symmetry in the problem. For illustration we employ a model QEP describing the motion of a beam simply supported at both ends and damped at the midpoint. We show that the above linearizations lead to poor numerical results for the beam problem, but that a two‐parameter scaling proposed by Fan, Lin and Van Dooren cures the instabilities. We also show that half of the eigenvalues of the beam QEP are pure imaginary and are eigenvalues of the undamped problem. Our analysis makes use of recently developed theory explaining the sensitivity and stability of linearizations, the main conclusions of which are summarized. As well as arguing that scaling should routinely be used, we give guidance on how to choose a linearization and illustrate the practical value of condition numbers and backward errors. Copyright © 2007 John Wiley & Sons, Ltd.
Reversed‐phase HPLC‐ESI/MS analysis of birch leaf proanthocyanidins after their acidic degradation in the presence of nucleophiles
Authors: Karonen Maarit , Leikas Anne , Loponen Jyrki , Sinkkonen Jari , Ossipov Vladimir , Pihlaja Kalevi
Published: May 2007

Mountain birch leaves contain large amounts of structurally variable polymeric proanthocyanidins. Their isolation procedure was enhanced by the addition of liquid–liquid extractions prior to column chromatography over Sephadex LH‐20. Isolated polymeric proanthocyanidins were depolymerised by acid‐catalysis in the presence of benzyl mercaptan or phloroglucinol in order to study their composition. The resulting degradation products, flavan‐3‐ols and flavan‐3‐ol adducts, were analysed with reversed‐phase high‐performance liquid chromatography using UV photodiode array detection for quantification and electrospray ionisation mass spectrometry for identification. The results showed that polymeric proanthocyanidins contained (epi)gallocatechins and (epi)catechins as the extension units and, mainly, (+)‐catechin as the terminal unit. The mean degree of polymerisation was found to be 26 based on thiolysis and 31 based on phloroglucinol degradation. Copyright © 2007 John Wiley & Sons, Ltd.
Missed opportunities for diagnosis of diabetes
Authors: Chudleigh R , Beaverstock J , Davis S , Hullin D , Evans Pms , Page Md
Published: May 2007

The objective of this study was to estimate the number of missed opportunities to diagnose abnormal glucose tolerance over a one‐year period in a district general hospital.

All patients with hyperglycaemia (≥ 7.0mmol/L) during one year were identified, and grouped by their glucose reading: 7.0–7.7mmol/L (group 1), 7.8–11.0mmol/L (group 2), and ≥ 11.1mmol/L (group 3). Patients with an HbA1c result from six months either side of this period were excluded. A retrospective audit of action taken, following identification of hyperglycaemia, was conducted. The following year a similar population was identified, and 75g oral glucose tolerance tests (OGTTs) were carried out on a sample of these individuals.

Initially, 3424 hyperglycaemic results were identified. Eighty‐eight sets of case notes were audited. In group 1, 17/25 (68%) had a written record of hyperglycaemia; further action was taken in 0/25 (0%). In group 2, 15/26 (58%) had a written record of hyperglycaemia; further action was taken in 6/26 (23%). In group 3, 11/23 (48%) had a written record of hyperglycaemia; further action was taken in 11/23 (48%). Overall, 71/88 (81%) had no clarification of glycaemic status. Of those clarified 10/17 (59%) were abnormal. In the second cohort, 85 OGTTs were conducted; 14/31 (45%) of group 1, 12/27 (44%) of group 2 and 15/27 (56%) of group 3 had abnormal OGTT results.

In our Trust, unexpected hyperglycaemia confers a 48% risk of abnormal glucose tolerance, and a 21% risk of established diabetes. Current procedures failed to identify most of these patients. Other hospitals should review their procedures and data. Copyright © 2007 John Wiley & Sons.
Qualitative study into quality of life issues surrounding insulin pump use in type 1 diabetes
Authors: Barnard Katharine , Skinner T Chas
Published: May 2007

Currently, there is a need for qualitative research about how insulin pump therapy changes quality of life, which is significant to people with type 1 diabetes. This study aimed to elicit the experiences of current insulin pump users in order to discover the therapy's benefits, downsides and effect on their quality of life. A qualitative approach was taken in order to reveal subjective experiences. This research will inform future research and assist with policy and guideline development by health care providers about pump therapy.

Participants were briefly interviewed by telephone about their experiences of living with an insulin pump. Four questions were asked. These covered the benefits of pump use, effects on quality of life, whether participants experienced downsides to using a pump and any other issues participants wished to raise.

In all, 80 insulin pump users participated in the study. All 80 reported experiencing benefits; insulin pump use had improved their quality of life. Key positive themes emerging from the data included greater control (45), flexibility (33), freedom (28), family effects (seven), convenience (seven) and independence (five). Key drawbacks emerging from the data included visibility— device (25), breakdown (17), visibility— skin (five) and cost (three).

Participants overwhelmingly reported experiencing benefits and improvements in their quality of life associated with insulin pump use. These pump users remain on pump therapy by choice, so the benefits clearly outweigh the downsides. However, further work needs to determine if these downsides contribute to explaining why 2–4% of pump users discontinue pump use after a short period of time, or whether this is a result of other factors. Copyright © 2007 John Wiley & Sons.
Synthesis, characterization and actuation behavior of polyaniline‐coated electroactive paper actuators
Authors: Kim Jaehwan , Yun Sung‐Ryul , Deshpande SD
Published: May 2007

This investigation deals with the synthesis, characterization and actuation behavior of conductive polyaniline‐coated electroactive paper actuators. The actuator is made by electrochemical deposition of conductive polyaniline on a cellulose paper. The aim of the investigation was to improve the bending displacement of electroactive paper actuators. The displacement outputs of the actuators show that a trilayer is better than a bilayer configuration. The nature of the dopant ion used in the electro‐generation affects the performance. A change in humidity plays a vital role in actuation performance of the actuators. Comparing the performance of electroactive paper actuators with and without a conductive polyaniline coating, the coating improves the displacement output threefold. Finally, the actuation principle mechanism is addressed. Copyright © 2007 Society of Chemical Industry
Synergistic effect of SEBS‐g‐MA and epoxy on toughening of polyamide 6/glass fiber composites
Authors: Xie Xiao‐Lin , Yu Zhong‐Zhen , Zhang Qing‐Xin , Zheng Gen‐Wen , Mai Yiu‐Wing
Published: May 2007

Maleated styrene‐ethylene‐butylene‐styrene block copolymer (SEBS‐g‐MA) and epoxy monomer, individually or in combination, are used to toughen polyamide 6/glass fiber composites. The epoxy monomer enhanced interaction between polyamide 6 and glass fiber. SEBS‐g‐MA rubber is uniformly dispersed in polyamide 6 matrix caused by the preferred compatibilizing reaction between the anhydride group of rubber and the amine terminal group of polyamide 6. The addition of epoxy does not affect the fine dispersion of SEBS‐g‐MA. Polyamide 6/glass fiber binary composites are brittle. The addition of epoxy monomer alone does not change their brittle features. Similarly, in the absence of epoxy monomer, adding 20 wt % of SEBS‐g‐MA to polyamide 6/glass fiber composites does not greatly increase the tensile ductility. Only when both SEBS‐g‐MA and epoxy monomer are present in some combination, do the polyamide 6/glass fiber composites show prominent ductile characteristics, such as stress‐whitening and necking. This synergistic effect of epoxy monomer and SEBS‐g‐MA also imparts higher notched impact strengths to the ternary composites. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1448–1458, 2007
Process safety culture in the CCPS risk based process safety model
Authors: Frank W.L.
Published: May 2007

The American Institute of Chemical Engineers (AIChE) Center for Chemical Process Safety (CCPS) has developed a guideline describing a new risk‐based approach that an organization can use in defining and implementing a process safety management system specific to its unique needs. Recognizing the importance of safety culture as a determinant of safety performance, CCPS has included process safety culture as one element in the new risk‐based process safety (RBPS) model. This paper will describe both the new process safety culture element and its integration in the overall RBPS model. © 2007 American Institute of Chemical Engineers Process Saf Prog 26:203–208, 2007
Soft Control of Scanning Probe Microscope with High Flexibility
Authors: Liu Zhenghui , Guo Yuzheng , Zhang Zhaohui , Zhu Xing
Published: May 2007

Most commercial scanning probe microscopes have multiple embedded digital microprocessors and utilize complex software for system control, which is not easily obtained or modified by researchers wishing to perform novel and special applications. In this paper, we present a simple and flexible control solution that just depends on software running on a single‐processor personal computer with real‐time Linux operating system to carry out all the control tasks including negative feedback, tip moving, data processing and user interface. In this way, we fully exploit the potential of a personal computer in calculating and programing, enabling us to manipulate the scanning probe as required without any special digital control circuits and related technical know‐how. This solution has been successfully applied to a homemade ultrahigh vacuum scanning tunneling microscope and a multiprobe scanning tunneling microscope. SCANNING 29: 000‐V000, 2007. © 2007 Wiley Periodicals, Inc.
Fluorescence Quenching by Colloidal Heavy Metals Nanoparticles: Implications for Correlative Fluorescence and Electron Microscopy Studies
Authors: Kandela Irawati K. , Albrecht Ralph M.
Published: May 2007

Labels for correlative immunolabeling in light (LM) and electron microscopy (EM) employing colloidal metal nanoparticles (gold or palladium) and fluorescent dyes (Alexa Fluor, AF) were investigated. The fluorescence signals from direct conjugates (cAu‐IgG‐AF) and from an indirect label system (cAu‐IgG‐anti IgG‐AF) were studied using scanning spectrofluorometry and fluorescence light microscopy.

Direct conjugation of protein—AF, IgG‐AF or FGN‐AF to 18 and 5 nm colloidal gold (cAu18 and cAu5) or 12 nm colloidal palladium particles (cPd12) resulted in nearly completely quenched fluorescence signals (>99 %) at excitation wavelengths of 488, 546 and 594 nm. In contrast, indirect conjugation, when colloidal metal particles and AF were conjugated to primary or secondary antibody, respectively (cAu‐IgG‐antiIgG‐AF), sufficient fluorescence signal was detected.

Commercially available conjugates, consisting of IgG‐AF‐cAu5 and IgG‐AF‐cAu10, were also tested and proved to be a mixture of IgG‐AF (unbound to cAu) and cAu‐IgG‐AF. SCANNING 29: 000‐V000, 2007. © 2007 Wiley Periodicals, Inc.
P‐values after repeated significance testing: A simple approximation method
Authors: Lee Young J. , Quan Hui
Published: April 2007

TheP‐value after a repeated significance test is a useful measure of the strength of evidence against the null hypothesis. Its computation, however, requires a computer‐intensive numerical integration method. TheP‐value is not conceptually straightforward, because it depends on how the sample space is ordered, which can be arbitrary. We look at two orderings of the sample space, one proposed by Tsiatiset al.and the other by Rosner and Tsiatis, and Chang. Although studies have shown that the latter ordering gives more reasonable confidence intervals than the former, the former gives a conservative and therefore more reasonableP‐value. Both, however, should yield an identicalP‐value in most applications. In this paper we present a simple method of approximatingP‐values. We provide tables to implement the method for two to ten stages with α = 0.1, 0.05 and 0.01 for the Pocock and O'Brien‐Fleming procedures. The proposed method can be applied to both orderings.
Exact conditional and unconditional sample size for pair‐matched studies with binary outcome: A practical guide
Authors: Royston Patrick
Published: April 2007

Tables of sample sizes for pair‐matched studies with binary outcome are presented. They are based on conditional and unconditional approaches using the ‘exact’ (binomial) test. An approximate procedure is suggested to estimate the sample size for parameter values that do not correspond exactly with table entries. The procedure utilizes a minor modification of the large‐sample formula given by Connett et al. A practical strategy for estimating the overall sample size in the presence of a nuisance parameter (the proportion of discordant pairs) is recommended. An example from a proposed clinical trial is given.
Evaluating the role of CD4‐lymphocyte counts as surrogate endpoints in human immunodeficiency virus clinical trials
Authors: Lin D. Y. , Fischl M. A. , Schoenfeld D. A.
Published: April 2007

In human immunodeficiency virus clinical trials, the CD4‐lymphocyte count has been regarded as a promising surrogate endpoint for clinical efficacy measures such as time to opportunistic infection and survival time. In the present paper, we test this hypothesis according to a criterion proposed by Prentice. This criterion requires the surrogate variable to capture the entire effect of treatment on the clinical endpoint, and it is satisfied if the hazard rate of the clinical endpoint is not affected by treatment among patients with the same preceding history of the surrogate variable. We analyse data from two completed zidovudine trials using the Cox regression model with the CD4‐lymphocyte count as a time‐varying covariate. The results indicate that the CD4‐lymphocyte count captures part of the relationship between zidovudine and time to a first critical event but does not fulfil the Prentice criterion.
Empirical bayes estimation and inference for the random effects model with binary response
Authors: Waclawiw Myron A. , Liang Kung‐Yee
Published: April 2007

Waclawiw and Liang introduced an estimating function‐based approach for estimating the parameters of the classical two‐stage random effects model for longitudinal data. In the present paper, the authors conduct a case study of the general approach for the binary response setting, where the fully specified parametric two‐stage model with fixed and univariate random effects has an analytically intractable likelihood. With successful convergence of the algorithm, the authors propose a fully parametric bootstrapping method for deriving empirical Bayes confidence intervals for all model parameters. The bootstrapping approach is a blend of the estimating function technique with the developments of Laird and Louis. The estimating function approach to estimation and inference provides a general framework for the analytis of a wide variety of medical data, including the setting of small and varying numbers of discrete repeated observations. An application of the methdology to the analysis of binary responses in a crossover clinical trial is presented.
A comparison of three approaches to estimate exposure‐specific incidence rates from population‐based case‐control data
Authors: Benichou Jacques , Wacholder Sholom
Published: April 2007

In population‐based case‐control studies, an attempt is made to identify all incident cases diagnosed in a specified population during a fixed time interval. Assuming that this goal is met allows one to obtain measures of risk other than relative risks. In this paper, we describe three approaches to estimate exposure‐specific incidence rates. Approach 1 relies on estimating crude incidence rates of the disease in strata defined, for instance, by age and geographic area, and combining them with relative risk estimates from the case‐control data. In approaches 2 and 3, baseline incidence rates and relative risks are estimated jointly. Approach 2 is based on a pseudo‐likelihood, while, in approach 3, the problem is regarded as a missing data problem and a full likelihood is maximized. We applied these three approaches to a study of bladder cancer. Our three sets of estimates of exposure‐specific incidence rates were in close agreement, while there appeared to be greater precision with approaches 2 and 3.
Smoothing grouped bivariate data to obtain the incubation period distribution of aids
Authors: Taylor Jeremy M. G. , Chon Yun
Published: April 2007

We use a penalized likelihood approach to obtain a smooth estimate of a bivariate distribution from grouped data where each observation consists of a region in a plane. The purpose of the analysis is to estimate the incubation period distribution of AIDS from the Multicenter AIDS Cohort Study, a prevalent cohort of homosexual men. In this article we illustrate the usefulness of the penalized likelihood approach. We also discuss the use of a cross‐validation and a Bayesian scheme to choose the smoothing parameters and bootstrap samples to assess uncertainty.
Comparison of alternative regression models for paired binary data
Authors: Glynn Robert J. , Rosner Bernard
Published: April 2007

We used simulated data, derived from real ophthalmologic examples, to evaluate the performance of alternative logistic regression approaches for paired binary data. Approaches considered were: standard logistic regression (ignoring the correlation between fellow eyes, treating individuals classified on the basis of their more impaired eye as the unit of analysis, or considering only right eyes); marginal logistic regression models fitted by the maximum likelihood approach of Lipsitz, Laird and Harrington or the estimating equation approach of Liang and Zeger; and conditional logistic regression models fitted by the maximum likelihood approach of Rosner or the estimating equation approach of Connolly and Liang. Taylor series approximations were used to compare conditional and marginal parameter estimates. Consideration of type I and II error rates found application of standard logistic regression to be inferior to methods that treated the eye as the unit of analysis and accounted for the correlation between fellow eyes. Among these latter approaches, none was uniformly superior to the others across the range of conditions considered.
A comparison of methods for testing homogeneity of proportions in teratologic studies
Authors: Donner Allan , Eliasziw Michael , Klar Neil
Published: April 2007

We consider teratologic studies in which the aim is to compare the survival rate of animals in a treatment group to the corresponding rate in a control group. The design of such studies often involves the allocation of intact litters of animals to treatment, invalidating the application of standard statistical methods. We review the strengths and weaknesses of several approaches for dealing with this problem including methodology recently developed for the analysis of clustered binary data. A simulation study is conducted in which litter sizes are generated from a distribution having specified mean and degree of imbalance. It is recommended on the basis of this study and on theoretical considerations that the choice of method should depend on whether the comparison of interest is experimental or observational. For experimental comparisons, involving the random assignment of litters to different treatment groups, methods based on the adjustment of standard chi‐square statistics are recommended unless the number of litters in each group is very large.
Triangular test and randomized trials: Practical problems in a small cell lung cancer trial
Authors: Pignon Jean‐Pierre , Tarayre Michèle , Auquier Ariane , Arriagada Rodrigo , le Chevalier Thierry , Ruffié Pierre , Rivière Alain , Monnet Isabelle , Chomy Pierre , Tuchais Claude
Published: April 2007

The triangular test has been used to monitor survival data from a randomized trial in patients with small cell lung cancer. The results of consecutive interim analyses and the problems met by the data monitoring committee and the co‐ordinators are described. The methods as well as the consequences of the early stopping on the analysis and the results of this trial are discussed. From this experience, we believe that statistical stopping rules ‐ only one of the factors to be taken into account when deciding to stop a trial ‐ should be used with caution. Independent data monitoring committees may be useful in helping to review the ongoing results and advise the participants in the trial.
Back‐projection of german AIDS data using information on dates of tests
Authors: Dietz Klaus , Seydel Johannes , Schwartländer Bernhard
Published: April 2007

The paper presents an application of back‐projection methods to the reported AIDS data which are collected by the AIDS Center in the Federal Office of Health, Berlin. The analysis is based on all data reported up to 31 December 1992. The data are broken down by major risk groups. Correction for reporting delays takes into account temporal changes in their distribution. The paper applies the EMS algorithm for the estimation of HIV incidence. The incubation period is modelled according to a convolution of several exponential distributions which describe time dependent phenomena like change of case definition and therapy effects. For each case it is reported whether an antibody test has been performed before diagnosis, and if yes, at what time this test was performed. The modelling of the incubation distribution takes into account the transition from a state ‘not yet tested’ into a state ‘tested’. Only tested individuals in three pre‐AIDS states are eligible for treatment. The model allows us to estimate not only the current total HIV prevalence but also a breakdown into those that are not yet tested, those that are tested but not yet treated and those that are under treatment. The results depend on the assumptions about the effect of treatment and on the degree of smoothing applied in the EMS algorithm.
Monitoring of a pilot toxicity study with two adverse outcomes
Authors: Etzioni Ruth , Pepe Margaret Sullivan
Published: April 2007

We consider monitoring a pilot toxicity study in which the adverse outcome is bivariate and the goal is to terminate the trial if evidence of excessive toxicity is encountered. We develop a Bayesian monitoring rule, based on the posterior probability that the frequency of either adverse outcome exceeds that observed under standard therapy. This rule is intuitive and ethical, and extends in a straightforward fashion from the univariate to the multivariate case. Since p‐values and confidence intervals are standard methods for reporting the results of clinical trials, we also suggest how frequentist inferences may be drawn at the conclusion of a study monitored in this fashion. This work thus represents an integration of Bayesian and frequentist methodology for sequential clinical trials.
Sample sizes for phase ii clinical trials derived from Bayesian decision theory
Authors: Brunier Hazel C. , Whitehead John
Published: April 2007

In early phase clinical trials of a new medical treatment, patients are treated to decide whether there is sufficient promise to justify additional studies. A decision theoretic approach is proposed to help determine the number of patients that should be treated. The optimal sample size is obtained by maximizing a utility function which incorporates both the number of ‘gained successes’ and the costs of treatment. The method extends work of Sylvester and Staquet, and adopts a Bayesian formulation. Numbers of patients in later studies and in eventual routine use of the treatment are taken into account. We allow for the possibility that a later study might lead to an erroneous conclusion. The effects of these various influences on the recommended sampling plan for the early phase clinical trial are explored.
Location—scale cumulative odds models for ordinal data: A generalized non‐linear model approach
Authors: Cox Christopher
Published: April 2007

Proportional odds regression models for multinomial probabilities based on ordered categories have been generalized in two somewhat different directions. Models having scale as well as location parameters for adjustment of boundaries (on an unobservable, underlying continuum) between categories have been employed in the context of ROC analysis. Partial proportional odds models, having different regression adjustments for different multinomial categories, have also been proposed. This paper considers a synthesis and further generalization of these two families. With use of a number of examples, I discuss and illustrate properties of this extended family of models. Emphasis is on the computation of maximum likelihood estimates of parameters, asymptotic standard deviations, and goodness‐of‐fit statistics with use of non‐linear regression programs in standard statistical software such as SAS.
Adenosine A2A receptor antagonists improve deficits in initiation of movement and sensory motor integration in the unilateral 6‐hydroxydopamine rat model of Parkinson's disease
Authors: Pinna Annalisa , Pontis Silvia , Borsini Franco , Morelli Micaela
Published: May 2007

Evidence obtained in rodent and primate models of Parkinson's disease (PD) and preliminary clinical trials, indicates that adenosine A2A receptor antagonists might represent a promising nondopaminergic therapeutic tool for the treatment of PD. Those studies demonstrated the ability of adenosine A2A receptor antagonists to potentiate l‐dopa‐mediated motor improvement, whereas very little is known about counteraction of specific motor deficits and on the effects of these compounds when administered alone. To this aim we evaluated the effects of different adenosine A2A receptor antagonists on initiation of movement deficits, gait impairment and sensory‐motor deficits, induced in rats by a unilateral 6‐hydroxydopamine lesion of dopaminergic nigrostriatal neurons. The following tests were used: (1) initiation time of stepping; (2) adjusting step (stepping with forelimb was measured as the forelimb was dragged laterally); (3) vibrissae‐elicited forelimb placing (as index of sensory‐motor integration deficits). Acute administration of the A2A receptor antagonists SCH 58261 (5 mg/kg i.p.) and ST 1535 (20 mg/kg i.p.) similarly to l‐dopa (6 mg/kg i.p.) counteracted the impairments in the initiation time of stepping test, in the adjusting step and in the vibrissae‐elicited forelimb placing induced by the lesion. The intensity of the effect was l‐dopa > SCH 58261 > ST 1535. The results provide the first evidence that blockade of A2A receptors is effective in antagonizing specific motor deficit induced by DA neuron degeneration, such as initiation of movement and sensory‐motor integration deficits, even without l‐dopa combined administration. Synapse 61:606–614, 2007. © 2007 Wiley‐Liss, Inc.
Ethanol's effect on intracellular signal pathways in prenatal rat cortical neurons is GABAB1 dependent
Authors: Lee H.Y. , Li S.P. , Park M.S. , Bahk Y.H. , Chung B.C. , Kim M.O.
Published: May 2007

To confirm the modulation role of GABAB on ethanol' effects, we studied the effects of ethanol on the neuronal intracellular signals, protein kinase A (PKA) and cAMP‐response element binding protein (CREB), by using a system where GABAB1 receptors were specifically knocked down in the in vitro cultivated cortical neurons. The results showed that the PKA α subunit was increased with ethanol treatment, and could be further increased by administering baclofen and phaclofen. By contrast, baclofen and/or phaclofen could decrease ethanol's up‐regulation effects on PKA α subunit expression in primary cultured cortical neurons in which the GABAB1 receptor was specifically knocked down using GABAB1 receptor RNA interference. Furthermore, these effects could lead to changes of phospho (p)‐CREB expression, which showed the same expression pattern as PKA. Finally, we observed changes of GABAB1, PKA, and p‐CREB distribution within the same neuronal cells. These results showed that the GABAB receptors are critical to ethanol's cellular effects, which occur via modulating the PKA and CREB transcription pathway, and may be an underlying cause of ethanol's effects. Synapse 61:622–628, 2007. © 2007 Wiley‐Liss, Inc.
Distribution, diversity and regulation of alcohol oxidase isozymes, and phylogenetic relationships of methylotrophic yeasts
Authors: Ito Takashi , Fujimura Shuki , Uchino Masataka , Tanaka Naoto , Matsufuji Yoshimi , Miyaji Tatsuro , Takano Katsumi , Nakagawa Tomoyuki , Tomizuka Noboru
Published: May 2007

In this study, we attempted to classify the methylotrophic yeasts based on diversities of alcohol oxidase (AOD), i.e. zymogram patterns and partial amino acid sequences. According to zymogram patterns for AOD, members of the methylotrophic yeasts separate into two major lineages, one group involving strains having a single AOD and the other group, including Pichia methanolica, Candida pignaliae and C. sonorensis, showing nine AOD isozymes. Based on partial amino acid sequences of AOD, the methylotrophic yeasts could be divided into five groups, and this classification agrees mostly with grouping based on 26S domain D1/D2 rDNA nucleotide sequences, except for some strains. Moreover, the strains having AOD isozymes constitute one group with P. trehalophila, P. glucozyma and Pichia sp. strain BZ159, although these strains are divided into two types, based on amino acid sequences of second AODs. On the other hand, these AOD isozymes consist of two subunits; the first subunits are induced not only by methanol but also by glycerol and pectin, although the second subunits are mainly induced by methanol. These data indicate that AOD isozymes and second AOD genes distribute widely in several methylotrophic yeasts in the natural environment, and second AOD genes may have evolved as methylotrophic genes that can adapt to the environmental conditions of higher methanol concentrations. Copyright © 2007 John Wiley & Sons, Ltd.
An Efficient Methodology for the Preparation of Alkoxyglycerols Rich in Conjugated Linoleic Acid and Eicosapentaenoic Acid
Authors: Torres Carlos F. , Vazquez Luis , Señoráns Francisco J. , Reglero Guillermo
Published: May 2007

Saponification of a raffinate obtained by supercritical fluid fractionation of shark liver oil was utilized for the production of an unsaponifiable fraction enriched in nonesterified alkoxyglycerols. Re‐esterification of the alkoxyglycerols produced with conjugated linoleic acid (CLA) and eicosapentaenoic acid in the presence of Candida antarctica lipase B was then studied. High yields (>90%) of diesterified alkoxyglycerols were obtained via esterification and transesterification with CLA, their respective ethyl ester, and eicosapentaenoic ethyl ester. The effect of a continuous purge stream of nitrogen on the kinetics of the reactions was also evaluated.