bluuebunny/crossref_metadata_2025 huggingface dataset:
Price Guarantees in Dynamic Pricing and Revenue Management
Authors: Levin Yuri , McGill Jeff , Nediak Mikhail
Published: February 2007

We present a new model for revenue management of product sales that incorporates both dynamic pricing and a price guarantee. The guarantee provides customers with compensation if, prior to a fixed future date, the price of the product drops below a level specified at the time of purchase. We consider the problem of simultaneously determining optimal dynamic price and guarantee policies for items from a fixed stock when demand depends both on the price and on the parameters of the price guarantee. The model can be used for pricing any items with limited availability over a fixed time horizon. We formulate this model as a discrete-time optimal control problem, prove the existence of its optimal solution, explore some of the structural properties of the solution, present lower-bounding heuristics for solving the problem, and report numerical results.
Equilibrium Forward Contracts on Nonstorable Commodities in the Presence of Market Power
Authors: Dong Lingxiu , Liu Hong
Published: February 2007

Bilateral supply contracts are widely used despite the presence of spot markets. In this paper, we provide a potential explanation for this prevalence of supply contracts even when spot markets are liquid and without delivery lag. Specifically, we consider the determination of an equilibrium forward contract on a nonstorable commodity between two firms that have mean-variance preferences over their risky profits and negotiate the forward contract through a Nash bargaining process. We derive the unique equilibrium forward contract in closed form and provide an extensive analysis. We show that it is the risk-hedging benefit from a forward that justifies its prevalence in spite of liquid spot markets. In addition, while a forward does not affect production decisions due to the presence of spot markets, it does affect inventory decisions of the storable input factor due to its hedging effect against the inventory risk. We also show that price volatilities and correlations are important determinants of the equilibrium contract. In particular, the equilibrium forward price can be nonmonotonic in the spot price volatility and can decrease as the initial spot price increases.
Robust Mean-Covariance Solutions for Stochastic Optimization
Authors: Popescu Ioana
Published: February 2007

We provide a method for deriving robust solutions to certain stochastic optimization problems, based on mean-covariance information about the distributions underlying the uncertain vector of returns. We prove that for a general class of objective functions, the robust solutions amount to solving a certain deterministic parametric quadratic program. We first prove a general projection property for multivariate distributions with given means and covariances, which reduces our problem to optimizing a univariate mean-variance robust objective. This allows us to use known univariate results in the multidimensional setting, and to add new results in this direction. In particular, we characterize a general class of objective functions (the so-called one- or two-point support functions), for which the robust objective is reduced to a deterministic optimization problem in one variable. Finally, we adapt a result from Geoffrion (1967a) to reduce the main problem to a parametric quadratic program. In particular, our results are true for increasing concave utilities with convex or concave-convex derivatives. Closed-form solutions are obtained for special discontinuous criteria, motivated by bonus- and commission-based incentive schemes for portfolio management. We also investigate a multiproduct pricing application, which motivates extensions of our results for the case of nonnegative and decision-dependent returns.
Wavelet modelling of collinearity judgment error
Authors: Greene Ernest , Ogden R. Todd
Published: February 2007

Prior research has found that participants manifest complex profiles of error when they are asked to judge collinearity of stimulus elements. These studies used harmonic analysis to model the data, and found large departures from accurate collinear judgments, with the amplitude and specific angular position of departures from valid judgment varying from one participant to the next. The models appeared to be a composite of many large‐, medium‐ and small‐scale departures, but this could not be established with any certainty because of the global nature of harmonic model components. Wavelet modelling is better suited to answer the question of whether the error profile is produced by independent sources that vary in size and location. Here, we examined judgments of collinearity of dot pairs across 360° of angular position. A priori and post hoc wavelet modelling strategies were used to identify independent sources of error that could not be attributed to chance, and some new statistical protocols were applied. We found evidence of error sources at several levels of scale, and these results were confirmed by the application of cross‐validation methods that make no assumption about the nature of the error probability distribution.
The rhetoric of acculturation: When integration means assimilation
Authors: Bowskill Matt , Lyons Evanthia , Coyle Adrian
Published: February 2007

Viewing traditional acculturation literature through a social constructionist lens, the present paper identifies a number of limitations with this research. A discourse analytic approach to acculturation is offered as a means of addressing some of these issues. Drawing on examples taken from British print media debate surrounding the issue of faith schooling in the UK, an analysis is presented which illustrates the manner in which, though optimally positioned within acculturative moral hierarchies directed towards the legitimization of both pro‐ and anti‐faith schooling debates, integration rhetoric often conceals the (re‐)production of a more implicit assimilationism. Findings are discussed in terms of their implications for hegemonically structured acculturative power relations. This exploratory analysis provides the basis for reflection on the benefits of a discursive approach to acculturation. Moreover, the dependence of integrationist discourse on a series of socio‐spatial resources is considered and, following on from Dixon and Durrheim's (2000) discursive re‐conceptualization of place‐identity, is taken to signify the need for a more environmentally ‘grounded’ approach to acculturation.
False belief understanding: The influence of person, grammatical mood, counterfactual reasoning and working memory
Authors: Müller Ulrich , Miller Michael R. , Michalczyk Kurt , Karapinka Aaron
Published: February 2007

The present study had two major goals. The first goal was to assess the relative difficulty among different versions of the unexpected contents task by systematically varying the dimensions of grammatical mood (indicative vs. subjunctive) and person (self vs. other), and to examine the correlational pattern between these different versions of the unexpected contents task and the unexpected locations task. The second goal was to examine the specificity of the relation between false belief understanding and counterfactual reasoning after controlling for age and working memory ability. One hundred, 3‐ to 6‐year‐old, children were administered two measures of false belief understanding (two versions of the unexpected contents task and two versions of the unexpected locations task), two measures of counterfactual reasoning and a working memory measure. Results showed that performance on the unexpected contents task did not significantly differ across conditions. However, only the conditions of the unexpected contents task that concerned another person's false belief correlated significantly with the unexpected locations task. Moreover, counterfactual reasoning was found to explain a significant amount of variance in the unexpected locations task, even after controlling for age and working memory performance. Findings are discussed in the context of different accounts of the development of theory of mind, and in the context of different interpretations of the relation between false belief understanding and counterfactual reasoning.
Sinus Bradycardia After Intravenous Pulse Methylprednisolone
Authors: Akikusa Jonathan D. , Feldman Brian M. , Gross Gil J. , Silverman Earl D. , Schneider Rayfel
Published: February 2007

High-dose intravenous pulse methylprednisolone is an important therapeutic modality for many autoimmune conditions in both children and adults. Adverse effects of this therapy include hypertension, hyperglycemia, and, in children, behavioral changes. Cardiac rhythm disturbances, both tachyarrhythmias and bradyarrhythmias, have been reported in adults but much less commonly in children. Here we report our experience over a 6-month period with 5 children with rheumatic diseases who developed sinus bradycardia during consecutive daily therapy with intravenous pulse methylprednisolone. Reductions in resting heart rate of between 35% and 50% of baseline were observed in each case. All patients were asymptomatic, and all recovered spontaneously over a variable period of time after cessation of pulse therapy. Sinus bradycardia after repeated administration of high-dose pulse methylprednisolone in children may be more common than previously appreciated.
Radiologic and Neurophysiologic Aspects of Stroke-like Episodes in Children With Congenital Disorder of Glycosylation Type Ia
Authors: Dinopoulos Argirios , Mohamed Ismail , Jones Blaise , Rao Sanjai , Franz David , deGrauw Ton
Published: February 2007

In an effort to shed light on the mechanism of hemiparetic stroke-like events experienced by patients with congenital disorder of glycosylation type Ia, we evaluated 3 children with this disorder by brain imaging studies and continuous electroencephalogram monitoring during such events. No evidence of ischemia or infarction was revealed on imaging studies and electrographic seizures or intermittent epileptiform activity was demonstrated on electrographic recordings. All 3 patients showed clinical and electrographic improvement after administration of antiepileptic medication. Epileptic phenomena can complicate the stroke-like events of patients with congenital disorder of glycosylation type Ia, and the cause of the hemiparesis may indeed be an active epileptic inhibitory process. As such, electroencephalogram monitoring is warranted, and treatment with anticonvulsant agents is indicated.
Once-Daily Highly Active Antiretroviral Therapy for HIV-Infected Children: Safety and Efficacy of an Efavirenz-Containing Regimen
Authors: Scherpbier Henriëtte J. , Bekker Vincent , Pajkrt Dasja , Jurriaans Suzanne , Lange Joep M. A. , Kuijpers Taco W.
Published: February 2007

OBJECTIVE. To improve adherence and virologic suppression, we assessed the feasibility and effectiveness of a once-daily regimen of efavirenz with 3 nucleoside reverse transcriptase inhibitors as first-line or second-line highly active antiretroviral therapy in a cohort of HIV-1–infected children.

METHODS. HIV-1–infected children naive to efavirenz were treated with a combination of efavirenz, abacavir, didanosine, and lamivudine in an observational, prospective, single-center study. Virologic failure-free survival was assessed with Kaplan-Meier analysis. The CD4+ T-cell increase was estimated by using a generalized linear model incorporating repeated measurements.

RESULTS. Thirty-six children received the study medication for a median of 69 weeks. Virologic failure-free survival rates were 76% and 67% after 48 weeks and 96 weeks, respectively. No significant difference was found in efficacy between first-line and second-line highly active antiretroviral therapy. All children receiving highly active antiretroviral therapy showed a sustained CD4+ T-cell increase, irrespective of virologic suppression. Growth rates improved with highly active antiretroviral therapy. Study medication administration was stopped for 14 children, mostly because of nonadherence (4 cases) or virologic rebound (5 cases) and because of adverse events (unrelated death and grade 2 liver toxicity) in 2 cases. Lipid abnormalities and abacavir-related hypersensitivity were not observed.

CONCLUSIONS. For the first time, once-daily highly active antiretroviral therapy is demonstrated to be a safe, convenient, and potent antiretroviral regimen for HIV-1–infected children.
DNA‐Binding Affinities and Sequence Specificities of Protoberberine Alkaloids and Their Demethylated Derivatives: A Comparative Study
Authors: Qin Yong , Chen Wen‐Hua , Pang Ji‐Yan , Zhao Zhong‐Zhen , Liu Liang , Jiang Zhi‐Hong
Published: February 2007

Berberrubine (1a), jatrorubine (2a), and palmatrubine (3a) have been chemically prepared by partial demethylation of berberine (1), jatrorrhizine (2), and palmatine (3), respectively. Their interactions with calf thymus (CT) DNA, poly(dA‐dT)⋅poly(dA‐dT), poly(dG‐dC)⋅poly(dG‐dC), and eight AT‐rich 12‐mer double‐stranded DNAs have been investigated by means of competitive ethidium bromide (EB) displacement experiments. The results showed that DNA‐binding affinities of these protoberberine alkaloids have been significantly improved by partial demethylation, and that all of these alkaloids have the preferable binding affinities with AT‐rich DNA. Especially, the sequence specificities of DNA‐binding of demethylated derivatives 1a, 2a, and 3a had changed to a certain extent when compared with the parent alkaloids 1, 2, and 3, respectively. The binding mode of these alkaloids was further confirmed by UV spectroscopic titration experiments. All the compounds bind to double‐stranded DNA most probably via an intercalating mode.
Preparation and PCR‐Amplification Properties of a Novel Amphiphilic Poly(N‐vinylpyrrolidone) (PVP) Copolymer
Authors: Zhang Lifen , Liang Yong , Meng Lingzhi , Lu Xiaoju , Liu Yunhai
Published: February 2007

A novel amphiphilic copolymer, P(NVP‐co‐TrpAMT) (9) was prepared, comprising hydrophilic N‐vinylpyrrolidone (NVP; 8) and hydrophobic ‘N‐[(tert‐butoxy)carbonyl]tryptophanamido‐N′‐methacryl thiourea’ (TrpAMT; 7) segments. The amphiphilic copolymer 9 was characterized by 1H‐NMR, GPC‐MALLS, TEM, and MTT assay. It has a critical micelle concentration (cmc) of 45.7 mg/l in aqueous solution, and good biocompatibility in vivo. According to TEM, the polymer is mostly present as spherical micelles in water, with a diameter of ca. 60–90 nm. In the presence of 0.1 μg/ml of 9, the PCR amplification of the GC‐rich β‐actin was efficiently enhanced. Also, the fluorescence intensity of the reporter dye SYBR Green I was increased by 26% at the 14th cycle during real‐time PCR of plasmid pUC18 DNA.
Environmentally Friendly, Efficient Resolution of Racemic Secondary Alcohols by Lipase‐Catalyzed Enantioselective Transesterification in Ionic Liquids in the Presence of Organic Bases
Authors: Wu Xiao‐Mei , Xin Jia‐Ying , Sun Wei , Xia Chun‐Gu
Published: February 2007

The lipase‐catalyzed enantioselective transesterification of racemic secondary alcohols was studied using vinyl acetate as acyl donor in two imidazolium‐based ionic liquids vs. hexane (Scheme), both in the absence and presence of catalytic amounts of organic bases such as triethylamine (Et3N) or pyridine. The organic bases generally enhanced both the rate and enantioselectivity of the reaction. Further, the system 1‐butyl‐3‐methyl‐1H‐imidazolium hexafluorophosphate/Candida antarctica lipase B ([bmim][PF6]/CALB) could be readily recycled four times without significant loss in activity or enantioselectivity (Table 4).
A Water‐Soluble, Octacationic Zinc Phthalocyanine as Molecular Probe for Nucleic Acid Secondary Structure
Authors: Zhang An‐Ming , Huang Jing , Weng Xiao‐Cheng , Li Jin‐Xi , Ren Li‐Ge , Song Zhi‐Bin , Xiong Xiao‐Qin , Zhou Xiang , Cao Xiao‐Ping , Zhou Yan
Published: February 2007

The interaction between CT‐DNA and the zinc phthalocyanine ZnPc (1) was studied by UV/VIS and fluorescence titration, as well as by thermal denaturation. ZnPc was found to strongly bind to CT‐DNA (Kapp=7.35×105  M−1) in a non‐intercalative mode. The photosensitized cleavage of pBR322 DNA was found to efficiently proceed via singlet‐oxygen (1O2) production. Further, ZnPc (1) caused site‐specific scission of guanine (G) bases around the bulge of the hairpin oligonucleotides OD1–OD3, as clearly shown by gel‐electrophoresis experiments.
Immunological Adjuvant Effect of Ginsenoside Rh4 from the Roots of Panax notoginseng on Specific Antibody and Cellular Response to Ovalbumin in Mice
Authors: Yang Zhi‐Gang , Ye Yi‐Ping , Sun Hong‐Xiang
Published: February 2007

Ginsenoside Rh4 (1), a saponin isolated from the roots of Panax notoginseng (Burk.) F. H. Chen, was evaluated for its haemolytic activity and adjuvant potential on specific antibody and cellular response to ovalbumin (OVA) in mice. Compound 1 showed a slight haemolytic effect, its concentration inducing 50% of the maximum haemolysis (HD50 value) being 407±12 μg/ml using a 0.5% suspension of red blood cells. Compound 1 significantly increased the concanavalin A (Con A)‐, lipopolysaccharide (LPS)‐, and OVA‐induced splenocyte proliferation in OVA‐immunized mice especially at a dose of 25 μg (P<0.05, P<0.01, or P<0.001). The OVA‐specific serum IgG, IgG1, and IgG2b antibody levels were also significantly enhanced by 1 at a dose of 25 μg compared to the OVA control group (P<0.05 or P<0.01). Moreover, the enhancing effect of 1 on the OVA‐specific IgG2b antibody responses to OVA in mice was more significant than that of Alum (Al(OH)3 gel; P<0.01). These results suggest that 1 could be safely used as adjuvant with low or non‐haemolytic effect.
Cyclopeptides from Sagina japonica (Caryophyllaceae)
Authors: Jia Ai‐qun , Tan Ning‐hua , Zhou Jun
Published: February 2007

Two new cyclic peptides, named sajaponicin C (1) and sajaponicin D (2), were isolated from the whole plants of Sagina japonica (Caryophyllaceae). Their structures were determined as cyclo(Pro2‐Leu2‐Tyr‐Leu1‐Phe1‐Pro3‐Phe2‐Pro1) (1) and cyclo(Pro1‐Pro2‐Pro3‐Pro4‐Phe1‐Gly‐Thr‐Ser‐Phe2‐Ile‐Tyr) (2) on the basis of spectroscopic data, especially by two‐dimensional (2D) NMR techniques.
Water‐Soluble Dendritic Core–Shell‐Type Architectures Based on Polyglycerol for Solubilization of Hydrophobic Drugs
Authors: Türk Holger , Shukla Anuj , Alves Rodrigues Paula Cristina , Rehage Heinz , Haag Rainer
Published: February 2007

Since many potential drugs are poorly water soluble, there is a high demand for solubilization agents. Here, we describe the synthesis of dendritic core–shell‐type architectures based on hyperbranched polyglycerol for the solubilization of hydrophobic drugs. Amphiphilic macromolecules containing hydrophobic biphenyl groups in the core were synthesized in an efficient three‐ or four‐step procedure by employing Suzuki‐coupling reactions. These species were then used to solubilize the commercial drug nimodipine, a calcium antagonist used for the treatment of heart diseases and neurological deficits. Pyrene was also used as a hydrophobic model compound. It turned out that the transport properties of the dendritic polyglycerol derivatives, which are based on hydrophobic host–guest interactions, depend strongly on the degree and type of core functionalization. In the case of the multifunctional nimodipine, additional specific polymer–drug interactions could be tailored by this flexible core design, as detected by UV spectroscopy. The enhancement of solubilization increased 300‐fold for nimodipine and 6000‐fold for pyrene at a polymer concentration of 10 wt %. The sizes of the polymer–drug complexes were determined by both dynamic light scattering (DLS) experiments and transmission electron microscopy (TEM), and extremely well‐defined aggregates with diameters of approximately 10 nm in the presence of a drug were observed. These findings together with a low critical aggregate concentration of 4×10−6 mol L−1 indicate the controlled self‐assembly of the presented amphiphilic dendritic core–shell‐type architectures rather than a unimolecular transport behavior.
Biology‐Oriented Synthesis of Stereochemically Diverse Natural‐Product‐Derived Compound Collections by Iterative Allylations on a Solid Support
Authors: Umarye Jayant D. , Leßmann Torben , García Ana B. , Mamane Victor , Sommer Stefan , Waldmann Herbert
Published: February 2007

A strategy aiming at the introduction of stereocenters into polymer‐bound natural‐product‐derived and ‐inspired compound collections is presented. Treatment of immobilized aldehydes with Brown's pinene‐derived allylboranes results in the stereoselective formation of homoallylic alcohols with up to 89 % ee (ee=enantiomeric excess). Subsequent iterative ozonolysis–allylation sequences with up to three allylations on a solid support give access to 1,3‐polyols with different relative configurations. Esterification with acryloyl chloride and final ring‐closing metathesis yields α,β‐unsaturated δ‐lactones with multiply oxygenated side chains, a substructure found in a group of natural products with a broad range of biological activity. The flexibility of the approach is exemplified by the parallel synthesis of all eight diastereomers of cryptocarya diacetate on a solid support. The individual isomers are obtained in overall yields of 40–60 % over 10 steps and with 63–85 % diastereoselectivity for the major isomer.
Synthesis and Liquid Crystalline Properties of Mono‐, Di‐ and Tri‐O‐alkyl Pentaerythritol Derivatives Bearing Tri‐, Di‐ or Monogalactosyl Heads: The Effects of Curvature of Molecular Packing on Mesophase Formation
Authors: Dumoulin Fabienne , Lafont Dominique , Huynh Thai‐Lê , Boullanger Paul , Mackenzie Grahame , West Jon J. , Goodby John W.
Published: February 2007

Self‐organisation and self‐assembly are critical to the stability of synthetic and biological membranes. Of particular importance is consideration of the packing arrangements of the various molecular species. Both phospho‐ and glycolipids can pack in ways in which curvature can be introduced into self‐organised or self‐assembled systems. For instance, it is known that the degree of curvature can affect the structures of any condensed phases that are formed. In this article we report on a systematic study in which we have varied the shapes of glycolipids and examined the condensed phases that they form. In doing so, we have also unified the shape dependency of lyotropic liquid crystals with those of thermotropic liquid crystals. In order to undertake this systematic study a range of different pentaerythritol derivatives was synthesized, which covers combinations of one to three alkyl chains of different lengths (6,7,9,10,11,12,14,16 carbon atoms) and three to one galactosyl heads. Mono‐ and di‐O‐galactosyl derivatives were prepared directly by glycosylation of the corresponding alcohols using 2,3,4,6‐tetra‐O‐benzoyl or acetyl‐α‐D‐galactopyranosyl trichloroacetimidate or bromide as the donors; the tri‐O‐galactosyl derivatives were synthesized from O‐alkyl‐O‐benzyl di‐O‐galactosyl pentaerythritol intermediates, followed by de‐O‐benzylation and glycosylation steps. All of the fully deprotected products were obtained by standard methods, and their self‐organising and self‐assembling properties examined.
The risk of renal impairment in hormone‐refractory prostate cancer patients with bone metastases treated with zoledronic acid
Authors: Oh William K. , Proctor Kevin , Nakabayashi Mari , Evan Carolyn , Tormey Lauren K. , Daskivich Timothy , Antràs Lucia , Smith Michael , Neary Maureen P. , Duh Mei Sheng
Published: February 2007

BACKGROUND

Bisphosphonates have been used to treat bone metastases in hormone‐refractory prostate cancer (HRPC), but certain agents have been associated with renal toxicity. For this observational study, the authors assessed the risk of renal impairment in patients with HRPC who received zoledronic acid from December 1999 to April 2005.

METHODS

A comprehensive medical records review was performed in a major tertiary oncology center (n = 122 patients). The primary outcome of renal impairment was defined as an increase ≥0.5 mg/dL or ≥1.0 mg/dL over baseline creatinine value if the baseline value was <1.4 mg/dL or ≥1.4 mg/dL, respectively. A risk factor analysis was conducted using the Andersen‐Gill extension to the Cox proportional hazards model.

RESULTS

Renal impairment was observed in 23.8% of patients. The risk of renal impairment increased with an extended duration of zoledronic acid therapy (<6 months, 11.1%; ≥24 months, 26.3%) and previous pamidronate treatment (45.5% vs 19.0% for patients with no prior pamidronate). A significantly greater risk of renal impairment was associated with increasing age at zoledronic acid initiation, prior pamidronate use, and a history of renal disease, hypertension, or smoking (P ≤ 0.05).

CONCLUSIONS

In an outpatient clinic setting, the risk of renal impairment among patients with HRPC who received zoledronic acid was greater than the risk reported previously in clinical trials. Cancer 2007 © 2007 American Cancer Society.
Mediastinal nodal staging of nonsmall cell lung cancer using integrated 18F‐FDG PET/CT in a tuberculosis‐endemic country
Authors: Kim Yoon Kyung , Lee Kyung Soo , Kim Byung‐Tae , Choi Joon Young , Kim Hojoong , Kwon O Jung , Shim Young Mog , Yi Chin A , Kim Ha Young , Chung Myung Jin
Published: February 2007

BACKGROUND

Integrated 18fluorine fluorodeoxyglucose (18F‐FDG) positron emission tomography/computed tomography (PET/CT) has shown somewhat variable sensitivity and specificity for mediastinal nodal staging in granulomatous disease endemic areas. The purpose of the study was to prospectively evaluate the efficacy of PET/CT for mediastinal nodal staging in nonsmall cell lung cancer (NSCLC) patients in a tuberculosis‐endemic country.

METHODS

Prospective assessment of the diagnostic efficacy of integrated PET/CT for detecting mediastinal nodal metastasis was performed in 674 patients (M:F ratio = 502:172; mean age, 61 years) with NSCLC. Patients underwent an integrated PET/CT examination and subsequent surgical nodal staging (by mediastinoscopy only in 121 patients and by thoracotomy in 553). Nodes showing greater 18F‐FDG uptake than mediastinum at PET without benign calcification or high attenuation >70 household unit (HU) at unenhanced CT were regarded as being positive for malignancy. The histologic nodal assessment results were used as reference standards.

RESULTS

Of 2477 mediastinal nodal stations evaluated in 674 patients, 275 (11%) stations in 180 (27%) patients proved to be malignant. On a per‐person basis, the overall sensitivity, specificity, and accuracy of PET/CT for mediastinal nodal staging were 61% (110 of 180), 96% (473 of 494), and 86% (583 of 674), respectively. On a per‐nodal station basis, they were 46% (126 of 275), 98% (2154 of 2202), and 92% (2280 of 2477).

CONCLUSIONS

Integrated PET/CT provides high specificity and reasonably high accuracy, but somewhat low sensitivity for mediastinal nodal staging of NSCLCs. The high specificity is achieved at the expense of sensitivity by interpreting calcified nodes or nodes with high attenuation at CT, even with high FDG uptake at PET, as benign in a tuberculosis‐endemic region. Cancer 2007. © 2007 American Cancer Society.
Quantitative analysis of neuronal diversity in the mouse olfactory bulb
Authors: Parrish‐Aungst S. , Shipley M.T. , Erdelyi F. , Szabo G. , Puche A.C.
Published: February 2007

Olfactory sensory information is processed and integrated by circuits within the olfactory bulb. Golgi morphology suggests the olfactory bulb contains several major neuronal classes. However, an increasingly diverse collection of neurochemical markers have been localized in subpopulations of olfactory bulb neurons. While the mouse is becoming the animal model of choice for olfactory research, little is known about the proportions of neurons expressing and coexpressing different neurochemical markers in this species. Here we characterize neuronal populations in the mouse main olfactory bulb, focusing on glomerular populations. Immunofluorescent labeling for: 1) calretinin, 2) calbindin D‐28K (CB), 3) parvalbumin, 4) neurocalcin, 5) tyrosine hydroxylase (TH), 6) the 67‐kDa isoform of GAD (GAD67), and 7) the neuronal marker NeuN was performed in mice expressing green fluorescent protein under the control of the glutamic acid decarboxylase 65kDa (GAD65) promoter. Using unbiased stereological cell counts we estimated the total numbers of cells and neurons in the bulb and the number and percentage of neurons expressing and coexpressing different neurochemical populations in each layer of the olfactory bulb. Use of a genetic label for GAD65 and immunohistochemistry for GAD67 identified a much larger percentage of GABAergic neurons in the glomerular layer (55% of all neurons) than previously recognized. Additionally, while many glomerular neurons expressing TH or CB coexpress GAD, the majority of these neurons preferentially express the GAD67 isoform. These data suggest that the chemospecific populations of neurons in glomeruli form distinct subpopulations and that GAD isoforms are preferentially regulated in different neurochemical cell types. J. Comp. Neurol. 501:825–836, 2007. © 2007 Wiley‐Liss, Inc.
Chemical organization of the macaque monkey olfactory bulb: III. Distribution of cholinergic markers
Authors: Porteros Ángel , Gómez Carmela , Valero Jorge , Calvo‐Baltanás Fernando , Alonso José Ramón
Published: February 2007

The distribution patterns of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) were studied in the olfactory bulb (OB) of three species of macaque. AChE was detected by a histochemical method and ChAT immunoreactivity by immunocytochemistry. Similar results were observed in all species analyzed. With the exception of the olfactory nerve layer, all layers of the macaque monkey OB demonstrated a dense innervation of AChE‐ and ChAT‐positive fibers. The distribution patterns of AChE‐ and ChAT‐labeled fibers were similar for both cholinergic markers, although the number of AChE‐labeled fibers was clearly higher than the number of ChAT‐immunoreactive fibers. The highest density of AChE and ChAT‐stained fibers was observed in the interface between the glomerular layer and the external plexiform layer and in the internal plexiform layer. Dense bundles of labeled fibers were observed in the caudal OB, coursing from the olfactory peduncle. All ChAT‐immunopositive elements were identified as centrifugal fibers, derived from neurons caudal to the OB. Neither olfactory fibers nor intrinsic neurons were observed after ChAT immunocytochemistry. However, a few AChE‐positive cells were observed in the glomerular layer and in both external and internal plexiform layers. These neurons were presumably identified as periglomerular cells, superficial short‐axon cells, and/or external tufted cells and deep short‐axon cells. Contrary to other neurotransmitters and neuroactive substances, the distribution patterns of ChAT and AChE activities in the macaque monkey OB closely resembled the patterns described in macrosmatic mammals and showed laminar differences with the distribution pattern observed in humans. J. Comp. Neurol. 501:854–865, 2007. © 2007 Wiley‐Liss, Inc.
Differential distribution of hyperpolarization‐activated and cyclic nucleotide‐gated channels in cone bipolar cells of the rat retina
Authors: Fyk‐Kolodziej Bozena , Pourcho Roberta G.
Published: February 2007

The hyperpolarization‐activated and cyclic nucleotide‐gated (HCN) channel isoforms HCN1, HCN2, and HCN4 were localized by immunofluorescence in the rat retina. Double labeling with the vesicular glutamate transporter (VGLUT1) was used to identify bipolar cell axon terminals in the inner retina. The HCN1 channel was localized to two cell types with differing intracellular distributions, insofar as staining was seen in the dendrites of a putative OFF‐type cone bipolar cell and in the axon terminals of an ON‐type bipolar that ramifies in stratum 3 (s3) of the inner plexiform layer (IPL). Staining for HCN4 was seen in two sets of bipolar axon terminals located in s2 and s3 and positioned between the two bands of choline acetyltransferase (ChAT) staining. The cells that ramify in s2 were identified as type 3 cone bipolar cells and the cells that ramify in s3 cells as a subclass of type 5 cone bipolars. The latter group, designated here as type 5b, exhibit diffuse axon terminals and can be distinguished from the narrowly stratifying type 5a cells. Double labeling showed that type 5b cone bipolar cells express both HCN1 and HCN4 as well as HCN2. Superposition of HCN channel labeling with VGLUT1 staining confirmed the presence of a cone bipolar cell whose terminals ramify in the same stratum of the IPL as type 5b cells but that do not express these HCN channels. J. Comp. Neurol. 501:891–903, 2007. © 2007 Wiley‐Liss, Inc.
The glutamate transporter EAAT2 is transiently expressed in developing human cerebral white matter
Authors: Desilva Tara M. , Kinney Hannah C. , Borenstein Natalia S. , Trachtenberg Felicia L. , Irwin Nina , Volpe Joseph J. , Rosenberg Paul A.
Published: February 2007

The major brain abnormality underlying cerebral palsy in premature infants is periventricular leukomalacia (PVL), a lesion of the immature cerebral white matter. Oligodendrocyte precursors (pre‐OLs; O4+O1−) predominate in human cerebral white matter during the peak time frame for PVL (24–32 gestational weeks) and are vulnerable to excitotoxicity. We hypothesize that PVL reflects, in part, excitotoxicity to pre‐OLs resulting from cerebral ischemia/reperfusion. Reversal of glutamate transport in the setting of energy failure is a major source of pathologic accumulation of extracellular glutamate. Here, we identify and localize the glutamate transporters in human cerebral white matter during the age range of PVL. In situ hybridization was performed with digoxigenin‐labeled probes directed against the full‐length coding regions of EAAT1, EAAT2, and EAAT3. EAAT2 mRNA was abundant in human fetal white matter during the period of peak incidence of PVL and virtually disappeared by 2 postnatal months. Its developmental profile differed significantly from that of both EAAT1 and EAAT3 mRNA. Immunoblotting demonstrated that EAAT2 protein was highly expressed in early development relative to adult values. Double‐label immunocytochemistry detected EAAT2 in OLs but not astrocytes or axons in the human fetal white matter. We conclude that transient expression of EAAT2 occurs during the window of peak vulnerability for PVL, suggesting that this developmentally up‐regulated transporter may be a major source of extracellular glutamate in ischemic injury to the cerebral white matter of the preterm infant. J. Comp. Neurol. 501:879–890, 2007. © 2007 Wiley‐Liss, Inc.
Untersuchungen zur Vermeidung von Rißschäden bei nicht tragenden Trennwänden
Authors: Brameshuber Wolfgang , Beer Ingo , Kang Bong‐Gu
Published: February 2007

Bislang werden die Verformungen von Stahlbetonbauteilen unter nicht tragenden Trennwänden nach DIN 1045‐1 auf 1/500 der Stützweite beschränkt, um Rißschäden in den Wänden zu vermeiden. Abgeleitet wurde dieser Richtwert durch Analyse von Bauschäden in den 60er Jahren. Direkte Untersuchungen zum Tragverhalten und damit auch zur Entstehung von Rissen in nicht tragenden Trennwänden wurden erst vor kurzem in einem vom Bundesamt für Bauwesen und Raumordnung geförderten Forschungsprojekt am Institut für Bauforschung durchgeführt.

In diesem Beitrag wird über die Ergebnisse des Forschungsprojektes, das sowohl einen Baustellenversuch an einer nicht tragenden, geschoßhohen Trennwand als auch Laborversuche und Finite‐Elemente‐Simulationen an geschoßhohen Wänden beinhaltet, berichtet.
Nachweis der Schubtragfähigkeit mit dem angepaßten Nachweisformat nach DIN 1053‐100
Authors: Kranzler Thomas , Schöps Peter
Published: February 2007

Mit dem Übergang auf das neue Sicherheitskonzept verschärfen sich durch zu untersuchende Lastkombinationen die Beanspruchungen auf aussteifende und stabilisierende Bauteile eines Gebäudes. Der Grund dafür liegt in der bauartunabhängigen Festlegung der Teilsicherheitsbeiwerte in Deutschland. Weiterhin haben sich im Rahmen der Überarbeitung der Normen für die Tragwerkseinwirkungen die anzusetzenden Horizontallasten infolge Wind und Erdbeben signifikant erhöht. Bei der gleichzeitig vom Bauherrn angestrebten Optimierung von Nutzflächen stehen diesem Sachverhalt immer geringer werdende Querschnittsflächen der Aussteifungswände gegenüber. Der Nachweis der Schubtragfähigkeit gewinnt damit vermehrt an Bedeutung. Auf der Widerstandseite steht dem mit DIN 1053‐100 nun eine Norm gegenüber, welche unter weitgehender Beibehaltung des bisherigen Status Quo von DIN 1053‐1 die Anwendung des Teilsicherheitskonzeptes bei der Bemessung von Mauerwerksbauten ermöglicht. Der vorliegende Beitrag befaßt sich mit dem Nachweis der Schubtragfähigkeit von unbewehrtem Mauerwerk nach DIN 1053‐100. Es werden die wesentlichen Neuerungen hinsichtlich der Nachweisführung sowie deren Hintergründe und Auswirkungen insbesondere hinsichtlich des neuen Sicherheitskonzeptes vorgestellt.
Tragfähigkeit von unbewehrtem Mauerwerk unter zentrischer und exzentrischer Druckbeanspruchung nach DIN 1053‐100
Authors: Graubner Carl‐Alexander , Jäger Wolfram
Published: February 2007

Der Beitrag befaßt sich mit der Tragfähigkeit von unbewehrtem Mauerwerk unter zentrischer und exzentrischer Druckbeanspruchung bei Anwendung des genaueren Berechnungsverfahrens nach DIN 1053‐100.

Mit dem Übergang auf das neue Sicherheitskonzept ist die Nachweisführung bei zentrischer und exzentrischer Beanspruchung auf den in Europa inzwischen üblichen Spannungsblock umgestellt worden. Die Berechnung wird dadurch erleichtert. Die Erfassung der Traglastminderung infolge exzentrischer Beanspruchung erfolgt über einen Abminderungsfaktor gegenüber der vollen Tragkraft bei zentrischer Kraftwirkung. Der Knicknachweis wird ebenfalls über einen Abminderungsfaktor, der in Wandmitte neben der exzentrischen Druckkraft auch die Anteile aus Theorie II. Ordnung berücksichtigt, geführt. Neue Erkenntnisse im Hinblick auf Tragreserven sind dabei eingeflossen. In dem Beitrag werden die Hintergründe und die Nachweisführung erläutert und auch die Auswirkungen auf die Systemtragfähigkeit von Mauerwerkswänden behandelt. Abgerundet wird die Thematik durch eine Gegenüberstellung der Traglasten nach DIN 1053‐1 und DIN 1053‐100.
Der Randdehnungsnachweis und seine Anpassung zur konsequenten Anwendung von DIN 1055‐100
Authors: Hoffmann Jens , Schöps Peter
Published: February 2007

Die bauaufsichtliche Einführung der neuen Windlastnorm DIN 1055‐4:2005‐03 bringt für viele Gebäudestandorte Windlasterhöhungen mit sich, die insbesondere den Nachweis von Schubwänden in Einfamilienreihenhäusern erschweren oder unmöglich machen können. Bemessungsmaßgebend wird hier oftmals der Randdehnungsnachweis. Der Beitrag beleuchtet die Sonderstellung von Schubscheiben in Einfamilienreihenhäusern und den Hintergrund des Randdehnungsnachweises. In diesem Zusammenhang wird über einen Vorschlag zur Kompensation der Mehrbelastung durch konsequente Anwendung der Lastkombinationsregeln in DIN 1055‐100 berichtet und abschließend eine Bemessungshilfe in Form eines Diagramms vorgestellt.
Synthesis and Structural Investigation of C4‐ and C2‐Symmetric Molecular Scaffolds Based on Imidazole Peptides
Authors: Haberhauer Gebhard , Pintér Áron , Oeser Thomas , Rominger Frank
Published: February 2007

The syntheses of a C4‐ and a C2‐symmetric scaffold are presented. The first is composed of four imidazole units, while the second contains two imidazole and two oxazole moieties. The synthesis of the key building block for both systems has been fundamentally improved. Starting from these scaffolds, various platforms possessing two or four arms can easily be prepared. The structures of the scaffolds, together with that of a C4‐symmetric oxazole scaffold, were investigated in the solid state and in the gas phase. We found that these 24‐membered cyclic peptides exist as two different structure types. In one case (type I), the nitrogen atoms of the azole units pointing into the interior of the macrocycle form a square, whereas in the second case (type II), they form a parallelogram. The type of molecular structure does not depend on the symmetry of the system, but on the type of azole used. Cyclic systems composed of four imidazole units are present in the type I structure, whereas systems consisting of four oxazole units exhibit the type II nature. Structure type II is also present in cycles composed of two oxazole units and two imidazole units. The existence of the different structure types can be explained in terms of the different orbital energies of the imidazole and oxazole systems. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Short Synthesis of Orthogonally Protected 3α,12α‐Diamino‐5β‐cholan‐24‐oic Acid, a Dipodal Steroid Scaffold for Combinatorial Chemistry
Authors: Verzele Dieter , Madder Annemieke
Published: February 2007

A short, practical, multigram‐scale synthesis of C3α‐NHAlloc, C12α‐NHBoc‐diamino‐5β‐cholan‐24‐oic acid 2 was developed, applying a new, straightforward synthetic strategy. Key features are the conservation of the carboxyl moiety at C24 during oxime reduction, the late differentiation between the C3 and C12 amino groups and the gradual separation of diastereomers during the synthesis. This orthogonally protected diamino steroid derivative can be used as starting point for the generation of steroid based dipodal peptide and non‐peptide combinatorial libraries. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Adding minority status to a source of conflict: an examination of influence processes and product quality in dyads
Authors: Smith Christine M.
Published: February 2007

Minority influence and conflict exposure were studied in an additive fashion within discussion dyads to clarify the role each plays in divergent thinking. Dyad types (determined by each member's preference for a political candidate) included: No conflict (both members preferred the same candidate, conflict only (each member preferred a different candidate), and minority status plus conflict (same as conflict only with one candidate labeled the minority candidate). Dyads chose a candidate, brainstormed to solve a problem, chose one solution and developed a proposal, and evaluated their interaction. The results showed that minority dyads' discussions of the political candidates were robust and resulted in direct minority influence. Additionally, brainstorming and proposal quality were positively affected by the minority source of influence. It appears that the status of the source of conflict plays a critical role in divergent thinking. Additionally, group products appear to be affected by individual divergent thinking. Copyright © 2007 John Wiley & Sons, Ltd.
A study on the condition for differential electrophoretic transport at a channel entrance
Authors: Pacheco J. Rafael , Chen Kang Ping , Hayes Mark A.
Published: February 2007

Electrophoretic differential transport of ionic species in a solution moving from a large reservoir into a small channel is investigated numerically. The system setup is similar to the experiments of Polson, Savin, and Hayes (J. Microcol. Sep. 2000, 12, 98), where the bulk flow into a fused‐silica capillary was driven by a pressure differential. A critical condition for achieving the defined differential transport near the channel entrance is found and this condition is solely determined by a dimensionless parameter when the geometry of the system is prescribed. This dimensionless parameter is the ratio between the electrophoretic migration velocity of the species based on the apparent electric intensity and the centerline fluid velocity of the fully developed channel flow. Species concentration distributions are also computed for various conditions. A separation technique can be derived from the experimental condition where a targeted division of species can be created at the channel entrance.
Design, characterization, and utilization of a fast fluorescence derivatization reaction utilizing o‐phthaldialdehyde coupled with fluorescent thiols
Authors: Hapuarachchi Suminda , Aspinwall Craig A.
Published: February 2007

We have developed a chemical derivatization scheme for primary amines that couples the fast kinetic properties of o‐phthaldialdehyde (OPA) with the photophysical properties of visible, high quantum yield, fluorescent dyes. In this reaction, OPA is used as a cross‐linking reagent in the labeling reaction of primary amines in the presence of a fluorescent thiol, 5‐((2‐(and‐3)‐S‐(acetylmercapto)succinoyl)amino)fluorescein (SAMSA fluorescein), thereby incorporating fluorescein (ϵ = 78 000 M−1, quantum yield of 0.98) into the isoindole product. Detection is based on excitation and emission of the incorporated fluorescein using the 488 nm laser line of an Ar+ laser rather than the UV‐excited isoindole, thereby eliminating the UV light sources for detection. Using this method, we have quantitatively labeled biologically important primary amines in less than 10 s. Detection limits for analysis of glutamate, glycine, GABA, and taurine were less than 2 nM. We present the characterization of OPA/SAMSA‐F reaction and the potential utility of the derivatization reaction for dynamic chemical monitoring of biologically relevant analytes using CE.
Tem‐induced gene mutations at enzyme loci in the mouse
Authors: Soares E. R.
Published: February 2007

Strain DBA/2J male mice were treated with triethylenemelamine (TEM) and subsequently mated to strain C57BL/6J females. Tissues from F1 progeny produced in these crosses were then examined using starch gel electrophoresis for the presence of presumed induced mutations at a series of 11 specific enzyme loci. In the course of this study, four heritable mutations were identified at the following loci: Es‐1, Ldh‐1, Pgm‐1, and Gpi‐1. Of these four, the first two were apparently segregating in parental males and were not TEM‐induced. Both of these are viable and fertile in the heterozygous and homozygous condition, and neither confers any readily apparent deleterious effect to the animal. The latter mutations (Pgm‐1 and Gpi‐1) are presumably induced. Although viable and fertile in the heterozygous state, we have not yet recovered any offspring homozygous for either of these two mutations.
Studies on the clastogenic effects of biologic stains and dyes
Authors: Au William , Hsu T. C.
Published: February 2007

We have surveyed the clastogenic potential of 12 different groups of stains and dyes totalling 48 compounds. We observed that 18 compounds induced significant increase in chromosome damage. Most of them were also found to be mutagenic, carcinogenic, or toxic in other reported studies. However, no significant studies were reported on six of them. It is concluded that these agents are potentially hazardous and should be studied further in detail.
A colorimetric assay of lysogenic induction designed for screening potential carcinogenic and carcinostatic agents
Authors: Elespuru R. K. , Yarmolinsky M. B.
Published: February 2007

Simple, rapid colorimetric tests for lysogenic induction (the derepression of a latent bacterial virus) are described. A quantitative test and a more rapid semiquantitative test are based on the assay of the β‐galactosidase synthesized from a lacZ gene fused to an operon under lambda repressor control. These biochemical “inductests” are suitable for screening programs designed to detect agents that damage DNA and that are of potential interest in carcinogenesis and cancer chemotherapy.