bluuebunny/crossref_metadata_2025 huggingface dataset:
“Catalysis in a Tea Bag”: Synthesis, Catalytic Performance and Recycling of Dendrimer‐Immobilised Bis‐ and Trisoxazoline Copper Catalysts
Authors: Gaab Manuela , Bellemin‐Laponnaz Stéphane , Gade Lutz H.
Published: April 2009

Trapped in a “tea bag”: Membrane bags, fabricated from a dialysis membrane, have been employed as semipermeable containers for dendrimer‐immobilised oxazoline–copper(II) Lewis acid catalysts. Dipping them into reactant solutions leads to the catalytic conversion of the substrates, which penetrate the membrane as does the product in the reverse direction (see scheme).

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Bis‐ and trisoxazolines (BOX and trisox), containing a linker unit in the ligand backbone that allows their covalent attachment to carbosilane dendrimers, have been employed as polyfunctional ligands for recyclable CuII Lewis acid catalysts that were immobilised in a membrane bag. The oxazolines contained an alkynyl unit attached to their backbone that was deprotonated with LDA or BuLi and then reacted with the chlorosilyl termini of zeroth‐, first‐ and second‐generation carbosilane dendrimers in the presence of TlPF6. The functionalised dendritic systems were subsequently separated from excess ligand by way of dialysis. The general catalytic potential of these systems was assessed by studying two benchmark reactions, the α‐hydrazination of a β‐keto ester as well as the Henry reaction of 2‐nitrobenzaldehyde with nitromethane. For both reactions the bisoxazoline‐based catalysts displayed superior selectivity and, in particular, catalyst activity. The latter was interpreted as being due to the hindered decoordination of the third oxazoline unit, the key step in the generation of the active catalyst, in the immobilised trisox–copper complexes. Solutions of the second‐generation dendrimer catalysts were placed in membrane bags, fabricated from commercially available dialysis membranes, with the purpose of catalyst recycling based on dialysis. Overall, the supported BOX catalyst gave good and highly reproducible results throughout the study, whereas the performance of the trisox dendrimer system decreased monotonically. The reason for the different behaviour is the markedly lower activity of trisox‐based catalysts relative to those based on the BOX ligand. This necessitated an increased reaction time for each cycle of the trisox derivatives, resulting in higher levels of catalyst leaching, which was attributed to a modification of the structure of the membrane by its exposure to the solvent trifluoroethanol at 40 °C.
Anion‐Templated Formation of Supramolecular Multinuclear Assemblies
Authors: Wezenberg Sander J. , Escudero‐Adán Eduardo C. , Benet‐Buchholz Jordi , Kleij Arjan W.
Published: April 2009

Anion meets host(s): Lewis acidic zinc(II)‐based salphen complexes have been found to interact strongly with various anions both in solution as well as in the solid state. A biologically relevant model anion (acetate, shown in red) has been exploited to serve as a molecular template for the synthesis of multinuclear Zn assemblies (Zn shown in green) with a short metal–metal distance, and consequently, resembles in part the metal‐ion proximity found in a range of multimetallic enzymes.

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The use of anions as supramolecular building motifs is reported herein. The interaction of various anions with [Zn(salphen)] complexes (salphen=N,N′‐phenylenebis(salicylideneimine)) has been studied, with a particular focus on assembly formation in the presence of acetate anions. Strong association of the latter with the Zn metal centre of the salphen complex was quantified by UV/Vis titration studies. The [Zn(salphen)]–OAc assemblies were further characterized by NMR spectroscopy and X‐ray analysis and revealed that the acetate anions can function as bridging modules between two [Zn(salphen)] units. The binding strength of a second complex to the acetate anion may be regulated by the substitution pattern of the salphen ligand. The anion‐templated assembly formation was further demonstrated by the supramolecular synthesis of a trinuclear Zn3 assembly. These results hold promise for the directed assembly formation of [Zn(salphen)] complexes with biologically relevant carboxylates, such as amino acids, and potentially new bio‐sensing materials.
The First Magnetic Nanoparticle‐Supported Chiral DMAP Analogue: Highly Enantioselective Acylation and Excellent Recyclability
Authors: Gleeson Oliver , Tekoriute Renata , Gun'ko Yurii K. , Connon Stephen J.
Published: April 2009

Recyclable organocatalysts: The first chiral DMAP analogue immobilized on magnetic nanoparticles is a highly active catalyst that is capable of the acylation of racemic sec‐alcohols under convenient, process‐scale friendly conditions (room temperature, 5 mol % loading, with acetic anhydride as the acylating agent) with excellent enantiodiscrimination. The catalyst is easily recovered and possesses unprecedented recyclability—in this study it was demonstrated to retain excellent activity and selectivity over 32 iterative cycles.

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CD‐sensitive Zn‐porphyrin tweezer host‐guest complexes, part 1: MC/OPLS‐2005 computational approach for predicting preferred interporphyrin helicity
Authors: Petrovic Ana G. , Chen Yihui , Pescitelli Gennaro , Berova Nina , Proni Gloria
Published: April 2009

This article describes a computational study on dimeric zinc porphyrin tweezer complexes with primary/secondary amines and secondary alcohols that validates the use of Optimized Potential for Liquid Simulations (OPLS‐2005) as the lead computational choice for assisting the tweezer methodology in the absolute configurational assignment of organic compounds. A supramolecular, microscale approach known as the tweezer method has been widely applied in the past decade for determining the absolute configuration of chiral substrates that are difficult to study by other readily available methods. The method relies on a host/guest complexation mechanism between a porphyrin tweezer moiety and a substrate, after its conversion into a bidentate conjugate. The formation of 1:1 complexes is a stereodifferentiating process: upon complexation, the originally achiral tweezer adopts a preferential interporphyrin helicity, dictated by the absolute configuration of the chiral substrate. By correctly predicting the sign of the interporphyrin helicity in the complex, OPLS‐2005 provides a correlation between the observed circular dichroism (CD) signal and the absolute configuration of the substrate. It also offers a great degree of insight into the structural factors responsible for chiral recognition and the amplitude of exciton couplets. Moreover, the preferential binding sites between the Zn‐tweezer and secondary amine conjugates were revealed by using the new computational approach. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
CD‐sensitive Zn‐porphyrin tweezer host‐guest complexes, part 2: Cis‐ and trans‐3‐hydroxy‐4‐aryl/alkyl‐β‐lactams. A case study
Authors: Chen Yihui , Petrovic Ana G. , Roje Marin , Pescitelli Gennaro , Kayser Margaret M. , Yang Yan , Berova Nina , Proni Gloria
Published: April 2009

This article describes an application of the host‐guest chiral recognition approach called tweezer methodology for the determination of the absolute configuration of 3‐hydroxy‐β‐lactams. These substrates represent challenging cases due to their chemical reactivity, the presence of multiple stereogenic centers and several functional groups which offer various possibilities of binding to the Zn‐porphyrin host. OPLS‐2005, the force field used in this work to predict the interporphyrin twist, modeled correctly the host‐guest complexation mechanism and revealed conformational details of the bound substrates. The computational study also suggested that in cases where an increase in the magnitude of the stereodifferentiation and an intense experimental CD are observed, the bound conformation of the conjugates are hydrogen bonded. The present investigation provides evidence that when the tweezer method is assisted by the OPLS‐2005 based computational approach, it can be successfully applied to the configurational and conformational elucidation of multi‐functional compounds with multiple stereogenic centers. Chirality, 2010. © 2009 Wiley‐Liss, Inc.
Near‐Infrared Emission Quantum Yield of Soluble Short Single‐Walled Carbon Nanotubes
Authors: Aprile Carmela , Martín Roberto , Alvaro Mercedes , Scaiano Juan C. , Garcia Hermenegildo
Published: April 2009

Soluble short single‐walled carbon nanotubes in aerated D2O emit in the near‐infrared (NIR) region (see picture) with a quantum yield of (3.9±0.5) ×10−3 and a half‐life of 7.65 μs. This emission is quenched by electron‐ acceptor molecules.

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Soluble short single‐walled carbon nanotubes (sSWNT) are prepared by means of chemical fragmentation and purification of commercial SWNTs. The average length of the nanotubes, as estimated by microscopy, is 400 nm. Infrared spectroscopy studies reveal the presence of a significant population of carboxyl groups. The thermogravimetric profile of an sSWNT shows that this material is hydrophilic, contains carboxyl groups, and is almost free from inorganic impurities. In D2O solution, the obtained sSWNTs emit in the near‐infrared (NIR) region with a quantum yield of (3.9±0.5)×10−3, determined using the 1270 nm singlet oxygen emission as a reference standard. The temporal profile can be fitted with first‐order kinetics and a half‐life of 13.9 μs. The NIR emission is quenched through a static mechanism by 2,4,6‐triphenylpyrylium (TP+), a typical electron acceptor.
CSR in business start‐ups: an application method for stakeholder engagement
Authors: Retolaza Jose Luis , Ruiz Maite , San‐Jose Leire
Published: April 2009

In this paper, we propose a Corporate Social Responsibility (CSR) method to apply in business start‐ups or newly created firms, whose main aim is the engagement of stakeholders. Several different CSR resources have been developed from various initiatives, both public and private. However, these initiatives do not highlight and consider the characteristics of newly created firms; moreover, most CSR theories and methods of applying social responsibility in firms are focused on medium and large firms, whose characteristics are so different, compared to start‐ups and newly created firms. The method proposed in this paper shows the possibility, at least theoretically, to implement a CSR method to tackle all of the interests of future and potential stakeholders in business start‐ups. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Solid‐State NMR Investigation of Ligand Mobility and Reactivity in Transition Metal Complexes
Authors: Chierotti Michele R. , Gobetto Roberto
Published: April 2009

Solid‐state NMR spectroscopy represents a powerful tool to access information on chemical structure, dynamics and reactivity at molecular level on solid compounds and materials. Transition metal complexes represent an unrestricted source of examples for solid‐state dynamics and reactivity due to the presence of highly mobile groups, very reactive ligands and the possibility of expanding the coordination sphere. The key question of the influence of the mobility on the reactivity of a system is the occasion for presenting several selected examples of solid‐state dynamics and reactivity of transition metal complexes. Although only few unambiguous examples are reported in which this correlation has been investigated, this review presents the central role of solid‐state NMR spectroscopy in the investigation of ligand motion, transformation mechanisms, kinetics and products of solid‐state reactions in transition metal complexes. The aim of this microreview is to offer the state‐of‐the‐art on this subject in order to develop new insights and to promote cooperative efforts in this fascinating field.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A Zinc Porphyrin Bearing Two Lateral dpp‐Containing Rings and Its [3]Pseudorotaxane (dpp: 2,9‐diphenyl‐1,10‐phenanthroline)
Authors: Roche Cécile , Sour Angélique , Niess Frédéric , Heitz Valérie , Sauvage Jean‐Pierre
Published: April 2009

A zinc porphyrin attached to two dpp‐containing rings was prepared from a 31‐membered ring with an attached pendent aldehyde function and 5‐mesityldipyrromethane by using the synthetic method introduced long ago by Lindsey and his group. The obtained porphyrin is of the ABAB type, with two mesityl groups on the 5‐ and 15‐positions and two macrocycles on the 10‐ and 20‐positions. From this compound, a [3]pseudorotaxane was obtained in good yield from the reaction of the porphyrin with two equivalents of a copper(I) salt followed by the addition of two equivalents of 2,9‐dianisyl‐1,10‐phenanthroline.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Discovering gorilla
Authors: Conniff Richard
Published: April 2009

On July 16, 1847, a missionary newly arrived in New York City from West Africa packed a collection of bones in a box and shipped them off to a colleague in Massachusetts. In a letter, Thomas S. Savage (Fig. 1), a graduate of Yale College and Yale Medical School, admitted to being “quite unwell,” probably meaning “utterly wretched.” He had already endured tropical diseases in Liberia off and on for more than a decade, and he'd seen his first two wives languish and die there, probably of malaria. He wasn't the sort to complain lightly.
Realization of contact resolving approximate Riemann solvers for strong shock and expansion flows
Authors: Kim Sung Don , Lee Bok Jik , Lee Hyoung Jin , Jeung In‐Seuck , Choi Jeong‐Yeol
Published: April 2009

The Harten–Lax–van Leer contact (HLLC) and Roe schemes are good approximate Riemann solvers that have the ability to resolve shock, contact, and rarefaction waves. However, they can produce spurious solutions, called shock instabilities, in the vicinity of strong shock. In strong expansion flows, the Roe scheme can admit nonphysical solutions such as expansion shock, and it sometimes fails. We carefully examined both schemes and propose simple methods to prevent such problems. High‐order accuracy is achieved using the weighted average flux (WAF) and MUSCL‐Hancock schemes. Using the WAF scheme, the HLLC and Roe schemes can be expressed in similar form. The HLLC and Roe schemes are tested against Quirk's test problems, and shock instability appears in both schemes. To remedy shock instability, we propose a control method of flux difference across the contact and shear waves. To catch shock waves, an appropriate pressure sensing function is defined. Using the proposed method, shock instabilities are successfully controlled. For the Roe scheme, a modified Harten–Hyman entropy fix method using Harten–Lax–van Leer‐type switching is suggested. A suitable criterion for switching is established, and the modified Roe scheme works successfully with the suggested method. Copyright © 2009 John Wiley & Sons, Ltd.
The evaluation of delirium post‐stroke
Authors: Manus John Mc , Pathansali Rohan , Hassan Hardi , Ouldred Emma , Cooper Derek , Stewart Robert , Macdonald Alastair , Jackson Stephen
Published: April 2009

Objective

The aim of this study was to assess and compare the Confusion Assessment Method (CAM) and the Delirium Rating Scale (DRS) in the detection of delirium in the acute stroke setting, when used by a non‐psychiatrist doctor.

Methods

Consecutive participants within 4 days of an acute stroke were screened for delirium using the CAM and the DRS. Patients also had a Mini‐Mental State Examination at each assessment. Patients were screened weekly for a maximum of 4 weeks. The CAM and DRS were compared against each other with respect to agreement and applicability.

Results

Of 110 eligible patients, 82 were recruited over a 7 month period. Delirium developed in 23 patients (28%), 21 of whom developed delirium during week 1. We found high agreement between the CAM and the DRS in the detection of stroke in the acute stroke setting (κ values 0.97, 0.86, 0.79 and 1 at weeks 1, 2, 3 and 4, respectively). In addition, there was strong correlation between low MMSE scores (MMSE less that 10) and delirium (κ scores 1.0, 0.82, 0.83 and 1.0 at weeks 1, 2, 3 and 4, respectively).

Conclusions

Delirium is a common complication post‐stroke. The CAM is equivalent to the DRS in the acute stroke setting when used by a trained non‐psychiatrist. A low MMSE score may have a small benefit in identifying patients that are at risk of having delirium. Copyright © 2009 John Wiley & Sons, Ltd.
A comparison of Granger causality and coherency in fMRI‐based analysis of the motor system
Authors: Kayser Andrew S. , Sun Felice T. , D'Esposito Mark
Published: April 2009

The ability of functional MRI to acquire data from multiple brain areas has spurred developments not only in voxel‐by‐voxel analyses, but also in multivariate techniques critical to quantifying the interactions between brain areas. As the number of multivariate techniques multiplies, however, few studies in any modality have directly compared different connectivity measures, and fewer still have done so in the context of well‐characterized neural systems. To focus specifically on the temporal dimension of interactions between brain regions, we compared Granger causality and coherency (Sun et al., 2004, 2005: Neuroimage 21:647–658, Neuroimage 28:227–237) in a well‐studied motor system (1) to gain further insight into the convergent and divergent results expected from each technique, and (2) to investigate the leading and lagging influences between motor areas as subjects performed a motor task in which they produced different learned series of eight button presses. We found that these analyses gave convergent but not identical results: both techniques, for example, suggested an anterior‐to‐posterior temporal gradient of activity from supplemental motor area through premotor and motor cortices to the posterior parietal cortex, but the techniques were differentially sensitive to the coupling strength between areas. We also found practical reasons that might argue for the use of one technique over another in different experimental situations. Ultimately, the ideal approach to fMRI data analysis is likely to involve a complementary combination of methods, possibly including both Granger causality and coherency. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Comparison of piece‐wise linear, linear, and nonlinear atlas‐to‐patient warping techniques: Analysis of the labeling of subcortical nuclei for functional neurosurgical applications
Authors: Chakravarty M. Mallar , Sadikot Abbas F. , Germann Jürgen , Hellier Pierre , Bertrand Gilles , Collins D. Louis
Published: April 2009

Digital atlases are commonly used in pre‐operative planning in functional neurosurgical procedures performed to minimize the symptoms of Parkinson's disease. These atlases can be customized to fit an individual patient's anatomy through atlas‐to‐patient warping procedures. Once fitted to pre‐operative magnetic resonance imaging (MRI) data, the customized atlas can be used to plan and navigate surgical procedures. Linear, piece‐wise linear and nonlinear registration methods have been used to customize different digital atlases with varying accuracies. Our goal was to evaluate eight different registration methods for atlas‐to‐patient customization of a new digital atlas of the basal ganglia and thalamus to demonstrate the value of nonlinear registration for automated atlas‐based subcortical target identification in functional neurosurgery. In this work, we evaluate the accuracy of two automated linear techniques, two piece‐wise linear techniques (requiring the identification of manually placed anatomical landmarks), and four different automated nonlinear atlas‐to‐patient warping techniques (where two of the four nonlinear techniques are variants of the ANIMAL algorithm). Since a gold standard of the subcortical anatomy is not available, manual segmentations of the striatum, globus pallidus, and thalamus are used to derive a silver standard for evaluation. Four different metrics, including the kappa statistic, the mean distance between the surfaces, the maximum distance between surfaces, and the total structure volume are used to compare the warping techniques. The results show that nonlinear techniques perform statistically better than linear and piece‐wise linear techniques. In addition, the results demonstrate statistically significant differences between the nonlinear techniques, with the ANIMAL algorithm yielding better results. Hum Brain Mapp, 2009. © 2009 Wiley‐Liss, Inc.
Vegetation controls on small‐scale runoff and erosion dynamics in a degrading dryland environment
Authors: Michaelides Katerina , Lister Debbie , Wainwright John , Parsons Anthony J.
Published: April 2009

This paper investigates the controls of vegetation on runoff and erosion dynamics in the dryland environment of Jornada, New Mexico, USA. As the American southwest has seen significant shifts in the dominant vegetation species in the past 150 years, an understanding of the vegetation effects on hydrological and erosional processes is vital for understanding and managing environmental change. Small‐scale rainfall simulations were carried out to identify the hydrological and erosional processes resulting from the grassland and shrubland vegetation species. Results obtained using tree‐regression analysis suggested that the primary vegetation control on runoff and erosion is the shrub type and canopy density, which directly affects the local microtopographic gradient of mounds beneath the shrubs. Significant interactions and feedbacks were found to occur among the local mound gradient, crust cover, soil aggregate stability and antecedent soil moisture between the different vegetation species for both the runoff and erosion responses. Although some of the shrub species were found to produce higher sediment yields than the grass species, the distinguishing feature of the grassland was the significantly higher enrichment in the fine sediment fraction compared to all other surface cover types. This enrichment in fines has important implications for nutrient movement in such environments. Copyright © 2009 John Wiley & Sons, Ltd.
Performance assessment of a GCM land surface scheme using a fine‐scale calibrated hydrological model: an evaluation of MOSES for the Nile Basin
Authors: Elshamy Mohamed Ezzat , Wheater Howard S.
Published: April 2009

Land surface schemes (LSSs) represent the interface between land surface and the atmosphere in general circulation models (GCMs). Errors in LSS‐simulated heat and moisture fluxes can result from inadequate representation of hydrological features and the derivation of effective surface parameters for large heterogeneous GCM gridboxes from small‐scale observations. Previous assessments of LSS performance have generally compared simulated heat and moisture fluxes to observations over a defined experimental domain for a limited period. A different approach has been evaluated in this study, which uses a fine‐resolution calibrated hydrological model of the study basin to provide a quasi‐observed runoff series for direct comparison with simulated runoff from a selected LSS at GCM scale. The approach is tested on two GCM gridboxes covering two contrasting regions within the Nile Basin. Performance is mixed; output from the LSS is generally compatible with that of the fine‐resolution model for one gridbox while it cannot reproduce the runoff dynamics for the other. The results also demonstrate the high sensitivity of runoff and evapotranspiration to radiation and precipitation inputs and show the importance of subtle issues such as temporal disaggregation of climatic inputs. We conclude that the use of a fine‐resolution calibrated model to evaluate a LSS has several advantages, can be generalized to other areas to improve the performance of global models and provides useful data that can be used to constrain LSS parameterizations. Copyright © 2009 John Wiley & Sons, Ltd.
Patterns of hematologic malignancies and solid tumors among 37,838 first‐degree relatives of 13,896 patients with multiple myeloma in Sweden
Authors: Kristinsson Sigurdur Y. , Björkholm Magnus , Goldin Lynn R. , Blimark Cecilie , Mellqvist Ulf‐Henrik , Wahlin Anders , Turesson Ingemar , Landgren Ola
Published: April 2009

There are emerging data to suggest a role for genetic factors in the pathogenesis of multiple myeloma (MM). Based on small numbers, certain solid tumors have been reported to occur more frequently among blood relatives of patients with MM. Using population‐based data, we assessed risks for hematologic malignancies, monoclonal gammopathy of undetermined significance (MGUS), and solid tumors among first‐degree relatives of patients with MM. We included 13,896 patients with MM and 54,365 matched controls. Also we identified first‐degree relatives of patients with MM (n = 37,838) and controls (n = 151,068). Using a marginal survival model, we estimated relative risks (RRs) and 95% confidence intervals (CIs) for hematologic and solid tumors among family members of patients with MM and controls as measures of familial aggregation. Compared with relatives of controls, relatives of patients with MM had an increased risk of developing MM (RR = 2.1; 95% CI 1.6–2.9), MGUS (2.1; 1.5–3.1), acute lymphoblastic leukemia (ALL) (2.1; 1.0–4.2), any solid tumor (1.1; 1.0–1.1) and bladder cancer (1.3; 1.0–1.5). No significantly increased risk was found for other hematologic or solid malignancies. Our findings support a role for a shared susceptibility (genetic, environmental or both) that predisposes to MM, MGUS, ALL and bladder cancer. © 2009 UICC
Detection of cell‐free BIRC5 mRNA in effusions and its potential diagnostic value for differentiating malignant and benign effusions
Authors: Wang Tingting , Qian Xiaoping , Wang Zhongqiu , Wang Lifeng , Yu Lixia , Ding Yitao , Liu Baorui
Published: April 2009

The detection of circulating nucleic acids has long been explored for the diagnosis of a variety of clinical conditions. The aim of this study was to detect the cell‐free mRNA expression of BIRC5 in patients with effusions and assess its potential diagnostic value. Pleural fluids and ascites samples were collected prospectively from 112 patients. The cell‐free RNA was extracted from effusions and the mRNA expression of BIRC5 was detected using real‐time RT‐PCR. The expression of carcinoembryonic antigen (CEA) and biochemical markers in effusions was also assayed. Effusions were classified as benign or malignant on the basis of their definitive pathologic or cytologic diagnoses. The expression of cell‐free BIRC5 mRNA was statistically significantly higher in the malignant group than in the benign group. BIRC5 mRNA was also significantly different between patients with Stage III and Stage IV non–small cell lung cancers. The sensitivity and diagnostic accuracy of BIRC5 were 79.0 and 81.3%, whereas a combination of CEA and BIRC5 reached 86.4% sensitivity and 88.4% accuracy. These results indicate that effusions with higher levels of cell‐free BIRC5 mRNA are more likely to be malignant. Determination of BIRC5 and CEA in effusions could enhance diagnostic value in the diagnosis of malignant effusions. © 2009 UICC
Heterogeneous ribonucleoprotein K is a marker of oral leukoplakia and correlates with poor prognosis of squamous cell carcinoma
Authors: Matta Ajay , Tripathi Satyendra Chandra , DeSouza Leroi V. , Grigull Jörg , Kaur Jatinder , Chauhan Shyam Singh , Srivastava Anurag , Thakar Alok , Shukla Nootan Kumar , Duggal Ritu , DattaGupta Siddhartha , Ralhan Ranju , Michael Siu K.W.
Published: April 2009

Oral leukoplakia is a heterogeneous lesion with risk of cancer development; there are no biomarkers to predict its potential of malignant transformation. Tissue proteomic analysis of oral leukoplakia using iTRAQ labeling liquid chromatography–mass spectrometry showed overexpression of heterogeneous ribonucleoprotein K (hnRNP K), a transformation‐related RNA‐binding protein, in leukoplakia in comparison with normal tissue. Herein, we investigated the clinical significance of hnRNP K in identification of oral leukoplakic lesions in early stages and as a prognostic marker in head‐and‐neck/oral squamous cell carcinomas (HNOSCCs). Immunohistochemical analysis of hnRNP K was performed in 100 HNOSCCs, 199 leukoplakias and 55 nonmalignant tissues and correlated with clinicopathologic parameters and disease prognosis over 6 years for HNOSCCs. hnRNP K nuclear expression increased from normal tissues to leukoplakia, and frank malignancy (p< 0.001). Cytoplasmic hnRNP K increased significantly from leukoplakia to HNOSCCs (p< 0.001) and was associated with poor prognosis of HNOSCCs (p= 0.011) by Kaplan–Meier analysis. The most important finding of our follow‐up study is that cytoplasmic hnRNP K is an independent predictor of disease recurrence in HNOSCC patients. In conclusion, nuclear hnRNP K may serve as a potential marker for early diagnosis, whereas its cytoplasmic accumulation can help to identify a subgroup of HNOSCC patients with poor prognosis, suggesting its putative utility in clinical management of HNOSCC. © 2009 UICC
Association of prostate stem cell antigen gene polymorphisms with the risk of stomach cancer in Japanese
Authors: Matsuo Keitaro , Tajima Kazuo , Suzuki Takeshi , Kawase Takakazu , Watanabe Miki , Shitara Kohei , Misawa Kazunari , Ito Seiji , Sawaki Akira , Muro Kei , Nakamura Tsuneya , Yamao Kenji , Yamamura Yoshitaka , Hamajima Nobuyuki , Hiraki Akio , Tanaka Hideo
Published: April 2009

A recent whole‐genome association study identified a strong association between polymorphisms in the prostate stem cell antigen (PSCA) gene and stomach cancer risk. In this case‐control study, we aimed to validate this association, and further to explore environmental factors possibly interacting with PSCA polymorphisms in 708 incident stomach cancer cases and 708 age–sex matched controls. The association between PSCA polymorphisms and Helicobacter pylori infection was also examined. We found that rs2294008 and rs2976392, which were strongly linked to each other (D′ = 1.00), were significantly associated with stomach cancer risk. Per allele odds ratio for rs2994008 was 1.40 (95% confidence interval: 1.19–1.65; p = 3.7 × 10−5). We found significant interaction with a family history of stomach cancer in first‐degree relatives (p‐heterogeneity = 0.009). Similar to originally reported association, we found significant heterogeneity between diffuse and intestinal type (p‐heterogeneity = 0.007). No association was seen between PSCA polymorphisms and H. pylori infection. In conclusion, PSCA polymorphisms are associated with stomach cancer risk in Japanese. A possible interaction with family history warrants further evaluation. © 2009 UICC
Conditions affecting cell seeding onto three‐dimensional scaffolds for cellular‐based biodegradable implants
Authors: Weinand Christian , Xu Jian Wei , Peretti Giuseppe M. , Bonassar Lawrence J. , Gill Thomas J.
Published: April 2009

Seeding cells efficiently and uniformly onto three‐dimensional scaffolds is a key element for engineering tissues, particularly when only a low‐number of cells is available for tissue repair and regeneration. The aim of this study was to evaluate three seeding techniques on two biocompatible scaffolds in vitro using chondrocytes as follows: (1) static; (2) modified centrifugal cell immobilization (CCI); and (3) dynamic oscillating motion. Five milliliters of media containing 5, 10, or 25 million articular, auricular, or costal chondrocytes were used to seed porous PLGA scaffolds and sections of devitalized cartilage. The dynamic oscillating technique resulted in up to 150% higher cellular load at 7 days than CCI seeding. Cell distribution was more homogeneous throughout the scaffold under dynamic conditions versus more sporadic and dispersed cell concentrations on the scaffolds when using either the static or the modified CCI technique. Cell load and distribution, when using a low numbers of chondrocytes at one and two million cells per milliliter, was comparable to that using the much higher number, especially under dynamic seeding conditions. The seeded scaffolds were used as implants to achieve cellular bonding between two devitalized meniscus discs. The constructs were implanted subcutaneously in nude mice for 12 weeks and analyzed histologically. Implants seeded with auricular chondrocytes showed qualitative more integration into native meniscus tissue than articular and costal cell implants. We conclude the dynamic oscillating seeding technique is an efficient technique for seeding low‐cell numbers onto scaffolds resulting in consistent and uniform cell distribution throughout porous PLGA scaffolds. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
High‐resolution 1H NMR investigations of the capacity of dentifrices containing a “smart” bioactive glass to influence the metabolic profile of and deliver calcium ions to human saliva
Authors: Grootveld Martin , Silwood Christopher J. L. , Winter Walter T.
Published: April 2009

Dentifrices containing H2O‐reactive bioactive glasses alleviate hypersensitivity in teeth via the blockage of open dentinal tubules. Here, the ability of two such products to release Ca2+ ions into human saliva was investigated, together with their influence on the status of this biofluid's 1H NMR‐detectable biomolecules. Human salivary supernatants were equilibrated with increasing volumes of those derived from each dentifrice (5.00 min at 37°C). These biofluids were also equilibrated at 37°C with a preselected quantity of the intact products (samples were collected at increasing timepoints). Salivary Ca2+ concentrations were monitored by a 1H NMR technique involving ethylenediamine tetra‐acetate addition and/or atomic absorption spectrometry. Added Ca2+‐ and dentifrice supernatant volume (DSV)‐induced modifications to the salivary 1H NMR profile were explored by spectral titration. Data acquired demonstrated added DSV‐dependent increases in salivary Ca2+ concentrations and (Ca2+‐independent) modifications to the intensities of selected salivary 1H NMR signals, particularly those of the malodorous amines methyl‐, dimethyl‐, and trimethylamines, which were diminished by up to 80% of their prior values. Time‐dependent elevations in salivary Ca2+ level were observed on equilibration with the intact dentifrices. Added Ca2+ ions exerted a concentration‐dependent influence on a range of resonances (including those of citrate, succinate, pyruvate, and lactate). These data provide valuable information regarding the mechanisms of action of the products tested. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
RGD modified PLGA/gelatin microspheres as microcarriers for chondrocyte delivery
Authors: Tan Huaping , Huang Dejuan , Lao Lihong , Gao Changyou
Published: April 2009

Poly(lactide‐co‐glycotide) (PLGA)/gelatin composite microspheres were prepared by an emulsion solvent evaporation technique. RGDS peptides were further immobilized under the catalyzation of water soluble carbodiimide (EDAC). Confocal laser scanning microscopy and transmission electron microscopy revealed that the gelatin was entrapped in the PLGA/gelatin microspheres with a manner of separated domains. The contents of the entrapped gelatin and immobilized RGDS peptides were quantified as 0.9 mg/20 mg and ∼2.1 μg/20 mg microspheres by hydroxyproline analysis and bicinchoninic acid protein assay, respectively. Moreover, difference in morphology of PLGA, PLGA/gelatin and RGDS modified PLGA/gelatin (PLGA/gelatin‐RGDS) microspheres was observed by scanning electron microscopy. The PLGA/gelatin and PLGA/gelatin‐RGDS microspheres lost their weight rapidly in PBS, but slowly in DMEM/fetal bovine serum. Rabbit auricular chondrocytes were seeded onto the microspheres in vitro to assess their biological performance and applicability as cell carriers. Results show that amongst the PLGA, PLGA/gelatin and PLGA/gelatin‐RGDS microspheres, the latter ones have the best performance in terms of chondrocyte attachment, proliferation, viability and sulfated glycosaminoglycans secretion. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Pseudoplasticity and setting properties of two‐solution bone cement containing poly(methyl methacrylate) microspheres and nanospheres for kyphoplasty and vertebroplasty
Authors: Rodrigues D. C. , Gilbert J. L. , Hasenwinkel J. M.
Published: April 2009

The viscosity and setting parameters of acrylic bone cements used for restoring vertebral compression fractures are critical factors in vertebroplasty and kyphoplasty procedures. Cements exhibiting lower viscosities and longer setting times are desired to overcome the difficulty of forcing the dough through small gauge needles and to reduce the risk of cementing them during surgery. However, cement extravasation is of great concern and can result when cements exhibiting lower viscosities are used. Therefore, the viscosity of cements should also be highly pseudoplastic to simultaneously facilitate flow through needles (shear‐thinning) and inhibit potentially deleterious extravasation by viscosity recovery at the delivery sites. The viscosity of two‐solution bone cement can be manipulated by changes in the polymer‐to‐monomer ratio and by the incorporation of cross‐linked poly(methyl methacrylate), (PMMA), microspheres or nanospheres in the polymer phase. In this study, the effect of the addition of cross‐linked PMMA particles to the linear polymer‐monomer solution with particle sizes ranging from 20–100 μm (microspheres) and 300–330 nm (nanospheres) is evaluated in terms of cement rheological properties and setting behavior. The addition of cross‐linked PMMA particles was observed to reduce the viscosity in comparison to the standard formulation while keeping the pseudoplastic characteristics, and to improve the setting properties by increasing curing time and reducing maximum exotherm significantly. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
TGFβ regulation of membrane mucin Muc4 via proteosome degradation
Authors: Lomako Wieslawa M. , Lomako Joseph , Soto Pedro , Carraway Coralie A. Carothers , Carraway Kermit L.
Published: April 2009

Muc4 is a heterodimeric membrane mucin implicated in epithelial differentiation and tumor progression. It is expressed from a single gene as a 300 kDa precursor protein which is cleaved in the endoplasmic reticulum to its two subunits. Our previous work has shown that Muc4 is regulated by TGFβ, which represses the precursor cleavage. Working with Muc4‐transfected A375 tumor cells, we now show that Muc4 undergoes proteosomal degradation. Proteosome inhibitors prolong the life of the precursor, shunt the Muc4 into cytoplasmic aggresomes, increase the level of Muc4 associated with the endoplasmic reticulum chaperones calnexin and calreticulin and increase the levels of ubiquitinated Muc4. Most importantly, proteosome inhibitors repress the TGFβ inhibition of Muc4 expression. These results suggest a model in which TGFβ inhibits precursor cleavage, shunting the precursor into the proteosomal degradation pathway. Thus, the cells have evolved a mechanism to use the quality control pathway for glycoproteins to control the quantity of the protein produced. J. Cell. Biochem. 107: 797–802, 2009. © 2009 Wiley‐Liss, Inc.
Disability and posttraumatic stress disorder in disaster relief workers responding to september 11, 2001 World Trade Center Disaster
Authors: Evans Susan , Patt Ivy , Giosan Cezar , Spielman Lisa , Difede JoAnn
Published: April 2009

Empirical evidence suggests that social and occupational disability plays a significant role in posttraumatic stress disorder (PTSD). The purpose of this study was to assess the role of social/occupational disability and to identify predictors of the development of PTSD in a group of disaster relief workers (DRWs) who had been deployed to the World Trade Center (WTC) following September 11, 2001. Eight hundred forty‐two utility workers completed a battery of comprehensive tests measuring PTSD and social occupational functioning. Results indicated a significant association between PTSD symptoms and impaired social/occupational functioning. Symptomatic workers were also more likely to have a history of trauma, panic disorder, and depression. Those with a history of trauma, depression, generalized anxiety disorder or panic reported significantly more disability than those without a psychiatric history. Careful screening of PTSD and social/occupational functioning in DRWs following a disaster is warranted so that early treatment can be undertaken to prevent a chronic and disabling course. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65: 1–11, 2009.
Intrusions related to obsessive‐compulsive disorder: a question of content or context?
Authors: Julien Dominic , O'Connor Kieron P. , Aardema Frederick
Published: April 2009

The aim of the current study was to investigate whether intrusions of individuals with obsessive‐compulsive disorder (OCD) and nonclinical individuals differed in content and in context of occurrence. The results suggest that although the intrusions of OCD and nonclinical individuals are similar in content, they differ in their context of occurrence. Chi square analyses revealed that the intrusions of nonclinical participants were more likely to be directly linked than indirectly linked to observations in the here and now, whereas the intrusions of participants with OCD were more prone to be indirectly linked than directly linked to triggers in the environment at the time they occurred. The implications of the results for cognitive models of OCD are discussed. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65: 1–14, 2009.
A comparison of Latino and Anglo socially desirable responding
Authors: Hopwood Christopher J. , Flato Claudia G. , Ambwani Suman , Garland Beth H. , Morey Leslie C.
Published: April 2009

Previous research suggests that Latinos tend to score higher than Anglos on psychometric indicators of socially desirable responding. The purpose of the current study was to test several methodological and cultural explanations for these group differences. Hypothesized explanations included varying levels of problems in living, measurement bias, differential structure of socially desirable responding measures, reliabilities of response style indicators, or cultural factors. Results supported previous findings that self‐identified Latino (N=143) respondents score significantly higher than Anglos (N=93) on some socially desirable responding indicators. Groups did not differ in levels of psychopathology and socially desirable responding indicators demonstrated structural similarity, equivalent relations to external criteria, and equivalent reliabilities across groups. Thus, data suggest normative differences between these groups in social presentation that should be considered in culturally sensitive clinical practice. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65:1–12, 2009.
3‐hydroxy 3‐methylglutaryl coenzyme A reductase increase is essential for rat muscle differentiation
Authors: Martini Chiara , Trapani Laura , Narciso Laura , Marino Maria , Trentalance Anna , Pallottini Valentina
Published: April 2009

3‐Hydroxy 3‐methylglutaryl coenzyme A reductase (HMG‐CoAR) is the key and rate‐limiting enzyme of cholesterol biosynthetic pathway. Although HMG‐CoAR activity has already been related to the differentiation of some cellular lines there are no studies that analyze the role of HMG‐CoAR, and the pathway it is involved with in a fully characterized muscle differentiation model. Thus, the aim of this work is to evaluate such role and delineate the pathway involved in foetal rat myoblasts (L6) induced to differentiate by insulin—a standard and feasible model of the myogenic process. The results obtained by biochemical and morphological approaches demonstrate that (i) HMG‐CoAR increase is crucial for differentiation induction, (ii) p21waf, whose increase is a necessary requisite for differentiation to occur, rises downstream HMG‐CoAR activation, (iii) the main role of p38/MAPK as key regulator also for HMG‐CoAR. Pathologies characterized by muscle degeneration might benefit from therapeutic programmes committed to muscle function restoration, such as modulation and planning myoblast differentiation. Thus, the important role of HMG‐CoAR in muscular differentiation providing new molecular basis for the control of muscle development can help in the design of therapeutic treatment for diseases characterized by the weakening of muscular fibers and aging‐related disorders (sarcopenia). J. Cell. Physiol. 220: 524–530, 2009. © 2009 Wiley‐Liss, Inc.
Risk Stratification tools for Transient Ischemic Attack: Which patients require hospital admission?
Authors: Cumbler Ethan , Glasheen Jeffrey J.
Published: April 2009

Stroke and transient ischemic attack (TIA) arise from identical etiologies and many fatal or disabling strokes are preceded by a TIA. Ten percent of patients presenting with a TIA will suffer a stroke within 3 months with half occurring in the first 48 hours. Still, many patients with a TIA do not receive timely evaluation or therapy. Hospitalization offers the opportunity for rapid evaluation and secondary prevention, reduced time to thrombolysis for early second strokes, and can be cost effective for high risk patients. Stratification tools are now available which allow individualized assessment of risk for early second strokes based on patient characteristics on presentation. The use of scoring systems such as the ABCD2 score to predict risk of stroke after TIA are useful in making an evidence‐based judgment regarding need for hospitalization. High‐risk patients have an 8.1% risk for stroke in the 48 hours after a TIA and warrant hospital admission. Intermediate‐risk patients have a 4.1% risk of early second stroke and may be considered for admission, observation, or expedited clinic evaluation. Low‐risk patients have a 2‐day stroke risk of only 1% and are likely appropriate for prompt outpatient evaluation. TIA is a medical emergency, similar to unstable angina, and high risk patients should receive treatment and prevention measures instituted with comparable urgency. Journal of Hospital Medicine 2009;4:247–251. © 2009 Society of Hospital Medicine.
Natural history of late discharges from a general medical ward
Authors: Chen Lena M. , Freitag Michael H. , Franco Manuel , Sullivan Christopher D. , Dickson Conan , Brancati Frederick L.
Published: April 2009

BACKGROUND:

Slow hospital discharges reduce efficiency and compromise care for patients awaiting a bed. Although efficient discharge is a widely held goal, the natural history of the discharge process has not been well studied.

OBJECTIVE:

To describe the discharge process and identify factors associated with longer and later discharges.

DESIGN:

Prospective cohort study.

SETTING:

A general medicine ward without house‐staff coverage, in a tertiary care hospital (The Johns Hopkins Hospital) in Baltimore, Maryland, from January 1, 2005 to April 30, 2005.

PATIENTS:

Two hundred and nine consecutively discharged adult inpatients.

MEASUREMENTS:

Discharge time (primary outcome) and discharge duration (secondary outcome).

RESULTS:

Median discharge time was 3:09 PM (25th% to 75th%: 1:08 to 5:00 PM). In adjusted analysis, discharge time was associated with ambulance used on discharge (1.5 hours), prescriptions filled prior to discharge (1.4 hours), subspecialty consult prior to discharge (1.2 hours), and procedure prior to discharge (1.1 hours). Median duration of the discharge process was 7 hours 34 minutes (25th% to 75th%: 4.0 to 22.0 hours). Discharge duration was associated with discharge to a location other than home (28.9 hours), and with need for consultation (14.8 hours) or a procedure (13.4 hours) prior to discharge (all P values <0.05).

CONCLUSIONS:

Discharge time and duration have wide variability. Longer and later discharges were associated with procedures and consults. Successful efforts to decrease time of discharge will require broad institutional effort to improve delivery of interdepartmental services. Journal of Hospital Medicine 2009;4:226–233. © 2009 Society of Hospital Medicine.