bluuebunny/crossref_metadata_2025 huggingface dataset:
Paragastric paraganglioma: A case report with unusual alveolar pattern and myxoid component
Authors: Laforga Juan B. , Vaquero Manuel , Juanpere Nuria
Published: March 2011

Paragangliomas are neural crest‐derived neuroendocrine tumors. Nearly 5 to 10% occur in extraadrenal sites, from the upper cervical region to the pelvis, related to the autonomic nervous system. Very few cases of gastric or paragastric paragangliomas have been reported. We report a paraganglioma attached to the stomach of an 85‐year‐old man. The tumor was 15 cm in diameter and was surgically resected via a subtotal gastrectomy. Fine‐needle aspiration smears showed round epithelioid cells forming acini and spindle cells attached to capillaries. Occasional cells showed excentric nuclei and pale vesicular cytoplasm. Microscopically, the tumor was characterized by an alveolar and solid pattern of growth with some unusual features, such as myxoid stroma and pseudoalveoli that contained myxoid material. Spindle cells stained with vimentin and S‐100 protein, whereas epithelioid cells showed diffuse cytoplasmic staining with chromogranin A. Electron microscopy of the tumor tissue revealed the presence of neurosecretory granules. To the best of our knowledge, this pattern of growth has yet to be described in the literature and may result in a misdiagnosis if sufficient immunohistochemical markers are not employed. We briefly discuss the cytomorphological features and differential diagnosis of this tumor, which was discovered in a rare location. Diagn. Cytopathol. 2012. © 2011 Wiley Periodicals, Inc.
Ultrasonography‐guided fine‐needle aspiration cytology for thyroid nodules: An emphasis on one‐sampling and biopsy techniques
Authors: Kim Dong Wook , Choo Hye Jung , Park Ji Sung , Lee Eun Joo , Kim Sang Hyo , Jung Soo Jin , Ryu Ji Hwa
Published: March 2011

The aim of this study was to assess the adequacy and efficacy of ultrasonography (US)‐guided fine‐needle aspiration cytology (US‐FNAC) with one‐sampling technique (only one specimen through a single needle pass was obtained during the procedure on each thyroid nodule in each study patient) for the cytological diagnosis of thyroid nodules.

In this study, US‐FNAC techniques, including “free two‐hand,” “mixed sampling,” “flipping‐extraction,” and “single‐needle‐pass” procedures were used to collect thyroid cells from July 2007 to June 2009. The cytopathology results and patients' complications were reviewed retrospectively.

Of the 1456 thyroid‐nodule samples obtained from 977 patients (1.49 per patient), the incidence of adequate and inadequate samplings was 88.5% (1289/1456) and 11.5% (167/1456), respectively. After thyroid surgery in 396 patients, 568 nodules were confirmed as 353 papillary thyroid carcinomas including one diffuse sclerosing variant, five follicular thyroid carcinomas, three medullary thyroid carcinomas, one anaplastic thyroid carcinoma, one metastatic renal cell carcinoma, two poorly differentiated carcinomas, 17 follicular adenomas, two nodular thyroiditis, two pseudonodules related to thyroiditis, and 182 cases of nodular hyperplasia. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, false‐negative rate, and false‐positive rate for the US‐FNAC were 94.3%, 91.9%, 96.2%, 88.3%, 93.6%, 3.9%, and 2.6%, respectively. There were no significant patients' complications, but 87 patients (8.9%) reported mild pain during or after the procedure.

This study showed a good adequacy and efficacy of US‐FNAC for thyroid nodules despite one‐sampling. Diagn. Cytopathol. 2012;40:E48–E54. © 2011 Wiley Periodicals, Inc.
Barr body in fine needle aspiration cytology of ovarian malignancies
Authors: Agrawal Pallavi , Dey Pranab
Published: March 2011

The Barr body is the inactive X chromosome in a female somatic cell. It is readily identified as plano‐convex structure of 2–3 micron in diameter on the periphery of the nuclear membrane. The aim of this study is to evaluate the significance of Barr body count in malignant ovarian tumors on fine needle aspiration cytology (FNAC) smears. In this retrospective study, Barr body was counted in FNAC smears of 20 successive malignant ovarian lesions and expressed as percentage. Mean (±SD) Barr body score was 2.4 ± 2.58. Minimum Barr body count was 1 and maximum was 9. The gross reduction of Barr body in ovarian neoplasms is an interesting cytomorphologic finding. Diagn. Cytopathol. 2012. © 2011 Wiley Periodicals, Inc.
A Combined Experimental and Theoretical Study on Bis(μ‐alkoxo)diiron(III) Complexes with Hydroxybenzylaminoethanol [O,N,O] Donor Ligands: Syntheses, Structures and Magnetic Properties
Authors: Hänninen Mikko M. , Colacio Enrique , Mota Antonio J. , Sillanpää Reijo
Published: March 2011

Three new neutral bis(μ‐alkoxo)diiron(III) complexes were prepared from N(R),N‐(2‐methylene‐4,6‐di‐tert‐butylphenol)aminoethan‐1‐ol ligands (H2L1, R = Me and H2L2, R = H). In these complexes, the ligand wraps around the metal center exhibiting a tridentate facial coordination mode with alkoxo‐bridging oxygen, amine nitrogen and phenoxo oxygen donor atoms. In the complex [Fe(acac)L1]2·MeCN (1) acetylacetonato coligand complete the distorted octahedral coordination spheres of the iron(III) ions, whereas in the five‐coordinate iron(III) chloride complexes [FeClL1]2 (2) and [FeClL2]2 (3) the ligands induce a geometry that is intermediate between square pyramidal and trigonal bipyramidal. Magnetic studies carried out on these dinuclear complexes showed that J values vary from –16.1 to –29.6 cm–1. Both experimental and theoretical DFT studies address a strong magneto‐structural correlation between the exchange coupling constant and the Fe–O–Fe angle of the complexes. The crossover point from antiferromagnetic to ferromagnetic coupling is predicted to be 100.4° for this family of N(R),N‐(2‐methylene‐4,6‐di‐tert‐butylphenol)aminoethan‐1‐ol ligands.
Investigating the formation and the properties of monoalkyl carbonates in aqueous medium using capillary electrophoresis with capacitively coupled contactless conductivity detection
Authors: Vidal Denis Tadeu Rajh , Nogueira Thiago , Saito Renata Mayumi , do Lago Claudimir Lucio
Published: March 2011

Although alkyl carbonic acids (ACAs) and their salts are referred to as instable species in aqueous medium, we demonstrate that a monoalkyl carbonate (MAC) can in fact be easily formed from bicarbonate and an alcohol even in the presence of a high amount of water. A CE system with two capacitively coupled contactless conductivity detectors (C4Ds) was used to obtain different parameters about these species and their reactions. Based on the mobilities obtained for a series of alcohols ranging from 1 to 5 carbons, the coefficients of diffusion and the hydrodynamic radii were calculated. When compared with the equivalent carboxylates, MACs have radii systematically smaller. Although the precise pKa values of the ACAs could not be obtained, because of the fast decomposition in acid medium, it was possible, for the first time, to show that they are below 4.0. This result suggests that the acidity of an ACA is quite similar to the first hydrogen of H2CO3. Using a new approach to indirectly calibrate the C4D, the kinetic constants and the equilibrium constants of formation were also obtained. The results suggest that the increase in the chain length makes the MACs less stable and more inert.
The Effect of Estimating Parameters on Long‐Term Forecasts for Cointegrated Systems
Authors: Chigira Hiroaki , Yamamoto Taku
Published: March 2011

This paper concerns Long‐term forecasts for cointegrated processes. First, it considers the case where the parameters of the model are known. The paper analytically shows that neither cointegration nor integration constraint matters in Long‐term forecasts. It is an alternative implication of Long‐term forecasts for cointegrated processes, extending the results of previous influential studies. The appropriate Mote Carlo experiment supports our analytical result. Secondly, and more importantly, it considers the case where the parameters of the model are estimated. The paper shows that accuracy of the estimation of the drift term is crucial in Long‐term forecasts. Namely, the relative accuracy of various Long‐term forecasts depends upon the relative magnitude of variances of estimators of the drift term. It further experimentally shows that in finite samples the univariate ARIMA forecast, whose drift term is estimated by the simple time average of differenced data, is better than the cointegrated system forecast, whose parameters are estimated by the well‐known Johansen's ML method. Based upon finite sample experiments, it recommends the univariate ARIMA forecast rather than the conventional cointegrated system forecast in finite samples for its practical usefulness and robustness against model misspecifications. Copyright © 2011 John Wiley & Sons, Ltd.
Individual variability in the shape and amplitude of the BOLD‐HRF correlates with endogenous GABAergic inhibition
Authors: Muthukumaraswamy Suresh D. , Evans C. John , Edden Richard A.E. , Wise Richard G. , Singh Krish D.
Published: March 2011

It has previously been demonstrated that there is a negative correlation between the amplitude of the BOLD response and resting γ amino‐butyric acid (GABA) concentration in visual cortex. The work here is the first to empirically characterize individual variability in the haemodynamic response functions (HRFs) in response to a simple visual stimulus and baseline GABA concentration in a population of young adult males (n = 15, aged 20–28 years). The results demonstrate that GABA concentration is negatively correlated with BOLD response amplitude (r = −0.64, P < 0.02) and positively correlated with HRF width (r = 0.67, P < 0.002), that is, individuals with higher resting GABA concentration tend to exhibit smaller and wider HRFs. No correlations were observed with resting cerebral blood flow and GABA concentration and similarly, no correlations were observed between GABA and the proportional tissue content of the MRS voxel. We argue that correlation of the height of the HRF is supportive of the view that the previously observed correlations between BOLD amplitudes and GABA are reflective of differences in neuronal activity. However, the changes in HRF shape in individuals with higher baseline GABA levels are suggestive that differing vascular response characteristics may also make a significant contribution. Our results reinforce the view that variability in endogenous factors, such as neurotransmitter concentration, can have a profound effect on the vascular haemodynamic response. This has important implications for between‐cohort fMRI studies in which variation in parameters such as GABA concentration may lead to group differences in the BOLD signal. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Is selective primary visual cortex stimulation achievable with TMS?
Authors: Salminen‐Vaparanta Niina , Noreika Valdas , Revonsuo Antti , Koivisto Mika , Vanni Simo
Published: March 2011

The primary visual cortex (V1) has been the target of stimulation in a number of transcranial magnetic stimulation (TMS) studies. In this study, we estimated the actual sites of stimulation by modeling the cortical location of the TMS‐induced electric field when participants reported visual phosphenes or scotomas. First, individual retinotopic areas were identified by multifocal functional magnetic resonance imaging (mffMRI). Second, during the TMS stimulation, the cortical stimulation sites were derived from electric field modeling. When an external anatomical landmark for V1 was used (2 cm above inion), the cortical stimulation landed in various functional areas in different individuals, the dorsal V2 being the most affected area at the group level. When V1 was specifically targeted based on the individual mffMRI data, V1 could be selectively stimulated in half of the participants. In the rest, the selective stimulation of V1 was obstructed by the intermediate position of the dorsal V2. We conclude that the selective stimulation of V1 is possible only if V1 happens to be favorably located in the individual anatomy. Selective and successful targeting of TMS pulses to V1 requires MRI‐navigated stimulation, selection of participants and coil positions based on detailed retinotopic maps of individual functional anatomy, and computational modeling of the TMS‐induced electric field distribution in the visual cortex. It remains to be resolved whether even more selective stimulation of V1 could be achieved by adjusting the coil orientation according to sulcal orientation of the target site. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
Routine central compartment lymph node dissection for patients with papillary thyroid carcinoma
Authors: Kutler David I. , Crummey Audrey D. , Kuhel William I.
Published: March 2011

Background

The role of routine central compartment neck dissection in papillary thyroid cancer is controversial.

Methods

A retrospective medical record review was conducted of 83 patients with papillary thyroid cancer who received either total or hemithyroidectomy and central compartment lymphadenectomy.

Results

Positive central compartment node metastases were found in approximately equal rates between older and younger patients (38.9% and 42.6%, respectively; Fisher's exact test; p = .82). The primary tumor was a microcarcinoma (1 cm or less) in 32 patients (38.5%). Positive central compartment node metastases were detected in 31.3% of patients with microcarcinomas, compared with 47.1% of patients with tumors greater than 1 cm.

Conclusion

Younger and older patients had approximately equal rates of central compartment lymph node metastasis. There was also a similar rate of metastasis between microcarcinomas and larger tumors. Our results document that central compartment lymph node dissection is a safe operation and may decrease the need for further operations. © 2011 Wiley Periodicals, Inc. Head Neck, 2012
MicroRNA expression during osteogenic differentiation of human multipotent mesenchymal stromal cells from bone marrow
Authors: Gao Jie , Yang Tongtao , Han Jianwei , Yan Kang , Qiu Xiuchun , Zhou Yong , Fan Qingyu , Ma Baoan
Published: March 2011

MicroRNAs comprise a group of non‐coding small RNAs (17–25 nt) involved in post‐transcriptional regulation that have been identified in various plants and animals. Studies have demonstrated that miRNAs are associated with stem cell self‐renewal and differentiation and play a key role in controlling stem cell activities. However, the identification of specific miRNAs and their regulatory roles in the differentiation of multipotent mesenchymal stromal cells (MSCs) have so far been poorly defined. We isolated and cultured human MSCs and osteo‐differentiated MSCs from four individual donors. miRNA expression in MSCs and osteo‐differentiated MSCs was investigated using miRNA microarrays. miRNAs that were commonly expressed in all three MSC preparations and miRNAs that were differentially expressed between MSCs and osteo‐differentiated MSCs were identified. Four underexpressed (hsa‐miR‐31, hsa‐miR‐106a, hsa‐miR‐148a, and hsa‐miR‐424) and three novel overexpressed miRNAs (hsa‐miR‐30c, hsa‐miR‐15b, and hsa‐miR‐130b) in osteo‐differentiated MSCs were selected and their expression were verified in samples from the fourth individual donors. The putative targets of the miRNAs were predicted using bioinformatic analysis. The four miRNAs that were underexpressed in osteo‐differentiated MSCs were predicted to target RUNX2, CBFB, and BMPs, which are involved in bone formation; while putative targets for miRNAs overexpressed in osteo‐differentiated MSCs were MSC maker(e.g., CD44, ITGB1, and FLT1), stemness‐maintaining factor(e.g., FGF2 and CXCL12), and genes related to cell differentiation(e.g., BMPER, CAMTA1, and GDF6). Finally, hsa‐miR‐31 was selected for target verification and function analysis. The results of this study provide an experimental basis for further research on miRNA functions during osteogenic differentiation of human MSCs. J. Cell. Biochem. 112: 1844–1856, 2011. © 2011 Wiley‐Liss, Inc.
Prognostic implication of ezrin expression in esophageal squamous cell carcinoma
Authors: Xie Jian‐Jun , Xu Li‐Yan , Wu Zhi‐Yong , Zhao Qing , Xu Xiu‐E , Wu Jian‐Yi , Huang Qiao , Li En‐Min
Published: March 2011

Background and Objectives

Ezrin, a member of the ezrin–radixin–moesin family, was implicated in tumor progression, metastatic dissemination, and adverse outcomes in several cancer types, including esophageal squamous cell carcinoma (ESCC). The purpose of this study was to explore the clinical significance of ezrin expression in ESCC.

Methods

Ezrin expression was detected on tissue microarrays of ESCC samples in 307 cases using immunohistochemical staining. Survival analysis was assessed by the Kaplan–Meier analysis. Relative risk was evaluated by the multivariate Cox proportional hazards model.

Results

The staining pattern of ezrin was heterogeneous and varied from negative/weakly to intense expression in a cytoplasmic distribution. Kaplan–Meier survival analysis showed that ezrin expression was related to poor overall survival of ESCC patients (P = 0.023). Further analysis revealed that ezrin expression was associated with the survival in the cases of stage III/IV (P = 0.002); but did not influence the survival in the patients of stage I/II. Multivariate Cox analysis demonstrated that ezrin was an independent factor in prognosis of ESCC (P = 0.011).

Conclusions

Ezrin might be a new molecular marker to predict the prognosis of ESCC patients. J. Surg. Oncol. 2011; 104:538–543. © 2011 Wiley‐Liss, Inc.
Over‐expression of LAPTM4B is associated with poor prognosis and chemotherapy resistance in stages III and IV epithelial ovarian cancer
Authors: Yin Mingzhu , Li Cong , Li Xia , Lou Ge , Miao Bing , Liu Xiaodong , Meng Fanling , Zhang Haiyu , Chen Xiuwei , Sun Meng , Ling Qiu , Zhou Rouli
Published: March 2011

Background

The purpose of this study was to determine whether LAPTM4B over‐expression is associated with the prognosis and chemotherapy resistance in patients with stages III and IV epithelial ovarian carcinoma, i.e., patients with peritoneal metastasis or lymph node metastasis of epithelial ovarian carcinoma.

Methods

LAPTM4B expression was evaluated in 10 normal ovarian and 113 stages III–IV ovarian carcinomas specimens by Western blotting analyses and immunohistochemistry. Univariate and multivariate analyses were performed to determine the association between LAPTM4B expression and prognosis and the relationship between LAPTM4B over‐expression and chemotherapy resistance.

Results

Western blotting analysis demonstrated that LAPTM4B was overexpressed in ovarian cancers, and immunohistochemistry results revealed that 80 patients were LAPTM4B over‐expression. The five‐year overall survival (OS) rates for patients with high LAPTM4B expression and low LAPTM4B expression were 27.36% and 90.7%, respectively (hazard ratio = 20.611, 95% CI: 5.916–71.808, P < 0.0001). The five‐year progression‐free survival (PFS) rate was 17.68% for patients in the high‐expression group and 84.42% for patients in the low‐expression group (hazard ratio = 17.852, 95% CI: 6.31–5.935, P < 0.0001); The presence of chemotherapy resistance was significantly associated with LAPTM4B expression (OR: 36.609, 95% CI: 4.737–282.941, P = 0.0006).

Conclusions

LAPTM4B over‐expression is an independent factor in stages III–IV epithelial ovarian carcinoma prognosis and chemotherapy resistance, and it may be an important potential biomarker. J. Surg. Oncol. 2011;104:29–36. © 2011 Wiley‐Liss, Inc.
Synthesis and Antitumoral Activity of Gelatin/Polyoxometalate Hybrid Nanoparticles
Authors: Guo Rui , Cheng Yuan , Ding Dan , Li Xiaolin , Zhang Leyang , Jiang Xiqun , Liu Baorui
Published: March 2011

Surfactant‐free gelatin/heptamolybdate (HM) hybrid nanoparticles are prepared by a simple and environmentally friendly approach utilizing the electrostatic interaction between anionic HM and the zwitterionic gelatin. The obtained nanoparticles have a tunable size and very high HM loading content up to about 70%. In vitro and in vivo experiments prove that the gelatin/HM hybrid nanoparticles exhibit significantly better antitumor activity than plain ammonium heptamolybdate solution. Therefore, the gelatin/HM hybrid nanoparticles reported here may serve as a prototype platform for polymer/polyoxometalate (POM) hybrid nanoparticles as cancer treatment agents and hence open up more opportunities to maximize the potential of POM‐based pharmaceutical agents.

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Diels–Alder Reactions as an Efficient Route to High Purity Cyclic Polymers
Authors: Glassner Mathias , Blinco James P. , Barner‐Kowollik Christopher
Published: March 2011

A simple and efficient route for the synthesis of cyclic polymer systems is presented. Linear furan protected α‐maleimide‐ω‐cyclopentadienyl functionalized precursors (poly(methyl methacrylate) and poly(tert‐butyl acrylate)) were synthesized via atom transfer radical polymerization (ATRP) and subsequent substitution of the bromine end‐group with cyclopentadiene. Upon heating at high dilution, deprotection of the dieneophile occurs followed by an intramolecular Diels–Alder reaction yielding a high purity cyclic product.

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Preparation and Flame Retardancy Properties of Novel PA12 and PE/Layered Titanoniobates Nanocomposites
Authors: Chausson Sophie , Retoux Richard , Rueff Jean‐Michel , Le Pluart Loïc , Madec Pierre‐Jean , Jaffres Paul‐Alain , Camino Giovanni
Published: March 2011

Summary: We report herein a study performed on a layered titanoniobate KTiNbO5 modified by octadecylamine to evaluate the fire retardancy properties of this novel hybrid nanofiller dispersed in PA12 and LLDPE, by polymer melt intercalation. The nanocomposites have been characterized using Electron Microscopy techniques to evaluate the degree of exfoliation and the morphologies. Thermogravimetric analyses and cone calorimeter tests have been carried out to assess the fire retardant performances.
γ‐Radiation Induced Functional Modification of Silica and Radiation Vulcanization of SBR‐Silica Composites
Authors: Dondi D. , Buttafava A. , Palamini C. , Pepori F. , Lostritto A. , Giannini L. , Nahmias M. , Conzatti L. , Faucitano A.
Published: March 2011

Summary: The γ‐ray induced “grafting” of polybutadiene olygomers onto precipitated silica and the radiation induced crosslinking of the blends prepared with the modified silica in SBR matrices have been investigated in the dose range up to 290 kGy. Enhanced mechanical properties have been detected for the SBR blends containing the modified silica after γ‐ray induced crosslinking. The comparison with the analogue mixtures containing pristine silica, supported by EPR measurements, suggests that the PB coating is effective in enhancing the mechanism of formation of filler‐rubber chemical links.
Synthesis of Additives from Montmorillonite to Modify High Density Polyethylene Final Properties
Authors: Elena Monasterio Fernanda , Alberto Destéfanis Hugo
Published: March 2011

Summary: This work brings about the modification of sodium montmorillonite clay (MNa) by the cationic exchange with hexadecyltrimethylammonium to turn it into organophilic clay (MC16). Subsequently, MC16 was treated with silanes. Three silanes with functional groups of different chemical nature were used. The objective was to determine if the clay could affect high density polyethylene (HDPE) final behavior after being modified with each silane. The following silanes were used: Cl2Si(CH3)2, Cl2Si(CH3)(C6H5) and Cl2Si(C6H5)2. Finally, in situ hydrolysis was carried out to generate the respective siloxanes. These materials were characterized by XRD, FTIR and GPC analyses. Each one of these additives was mixed using melt compounding processing in a Haake torque rheometer Rheocord 9000 equipped with a mix chamber and roller rotors at 100 rpm and 190 °C. All hybrids were characterized by XRD, SEM and thermogravimetric analyses. Barrier properties to cyclohexane were also determined by pervaporation experiments. Results from all studies showed that the addition of approximately 3 wt% of clay has changed the macroscopic properties of the above‐mentioned composites, as compared with pure HDPE. This can be explained considering the different polymer/filler interactions which take place in each system.
Polymer Nanocomposites Containing Fullerene C60 Nanofillers
Authors: Zuev V.V.
Published: March 2011

Summary: The effect of fulleroids (fullerene C60, mixture of C60/C70 and fulleroids soot which used for fullerenes production) and carbon fillers (carbon black, graphite) on mechanical properties of polymer nanocomposites based on reactoplasts (epoxy resins) and thermoplasts (polyamide‐12) was investigated. The nanocomposites were prepared by in situ polymerization. It was found that additives of these fillers did not influenced on the properties of reactoplasts. Therefore, the tensile modulus and tensile strength of thermoplast based polymer nanocomposites are improved by about 30‐40% with loading of 0.02‐0.08 fulleroids materials. Best results were obtained for a mixture of C60/C70.
Growth Response of Trichoderma Species to Organic Solvents
Authors: Oros Gyula , Naár Zoltán , Cserháti Tibor
Published: March 2011

The growth response of 25 Trichoderma strains to 26 alkanols and 7 other organic solvents was examined in vitro. The sensitivity of strains considerably varied depending on their taxonomic position, thus the strains of Longibrachiatum section proved to be more tolerant than those of Pachybasium and Trichoderma sections.

Significant relationship was revealed between structure of C1–C24 alkanols and their growth inhibitory effect to Trichodermas, both efficacy and selectivity of C1–C3 and C14–C24 alkanols failed off the C9–C11 alkanols. The non‐alkanol solvents tested were non‐toxic.

The C8‐C11 alkanols used in agricultural practices exhibited noticeable toxicity to all Trichoderma strains, therefore pesticidal preparations containing these alkanols cannot be used simultaneously with Trichoderma based biopreparations.
CADASTER QSPR Models for Predictions of Melting and Boiling Points of Perfluorinated Chemicals
Authors: Bhhatarai Barun , Teetz Wolfram , Liu Tao , Öberg Tomas , Jeliazkova Nina , Kochev Nikolay , Pukalov Ognyan , Tetko Igor V. , Kovarich Simona , Papa Ester , Gramatica Paola
Published: March 2011

Quantitative structure property relationship (QSPR) studies on per‐ and polyfluorinated chemicals (PFCs) on melting point (MP) and boiling point (BP) are presented. The training and prediction chemicals used for developing and validating the models were selected from Syracuse PhysProp database and literatures. The available experimental data sets were split in two different ways: a) random selection on response value, and b) structural similarity verified by self‐organizing‐map (SOM), in order to propose reliable predictive models, developed only on the training sets and externally verified on the prediction sets. Individual linear and non‐linear approaches based models developed by different CADASTER partners on 0D‐2D Dragon descriptors, E‐state descriptors and fragment based descriptors as well as consensus model and their predictions are presented. In addition, the predictive performance of the developed models was verified on a blind external validation set (EV‐set) prepared using PERFORCE database on 15MPand 25BPdata respectively. This database contains only long chain perfluoro‐alkylated chemicals, particularly monitored by regulatory agencies like US‐EPA and EU‐REACH. QSPR models with internal and external validation on two different external prediction/validation sets and study of applicability‐domain highlighting the robustness and high accuracy of the models are discussed. Finally,MPs for additional 303 PFCs andBPs for 271 PFCs were predicted for which experimental measurements are unknown.
Structural Bioinformatics Approach of Cyclin‐Dependent Kinases 1 and 3 Complexed with Inhibitors
Authors: Saraiva Lucas A. , Veloso Marcia P. , Camps I. , da Silveira Nelson J. F.
Published: March 2011

The cyclin‐dependent kinases or CDKs participate in the regulation of both the cell progression cycle and the RNA polymerase‐II transcription cycle. In several human tumours deregulation of CDK‐related mechanisms have been detected, e.g., overexpression of cyclins or deletion of genes encoding for CKIs. Regarding these observations, CDKs came up to be interesting targets for elaboration of novel antitumour drugs. Based on the importance of the CDKs, this research aimed to describe, to characterize and to compare the molecular models of CDK1 and CDK3. Since the structures of human CDK1 and CDK3 are unavailable in the Protein Data Bank –PDB, homology models were created based on the CDK2 as the template, once they share a substantial identity. The structural studies of the CDK1 and CDK3 biding sites were conducted by molecular docking with 15 different CDK inhibitors previously identified to CDK2. This study allowed the understanding of the structure of the complexes between CDK1/ CDK3 with inhibitors. The knowledge of their structural features mainly the biding sites might be useful to discovery and rationalization of drug design process.
On the Use of Local and Global QSPRs for the Prediction of Physico‐chemical Properties of Polybrominated Diphenyl Ethers
Authors: Papa Ester , Kovarich Simona , Gramatica Paola
Published: March 2011

Polybrominated diphenyl ethers (PBDEs) are persistent chemicals that have been among the most marketed flame retardants used all over the world in the last decades. PBDEs have been detected in all environmental compartments, as well as in humans and wildlife, where they are able to accumulate and exert their toxic effects. At present only a limited amount of experimental data is available to characterize the physico‐chemical and toxicological behavior of PBDEs and similar brominated flame retardants. QSA(P)R approaches are very useful tools to predict missing data starting from the chemical structure of compounds. In this study several local QSPR models, developed specifically for the prediction of logKoa, logKow and melting point of PBDEs, were compared with predictions by global QSPR models, such as KoaWIN, KowWIN and MPBPWIN from the EPI Suite package, and AlogP and MlogP from DRAGON software, which were trained on heterogeneous and large datasets. The analysis addressed in the paper supported the identification of points of strength and weaknesses of both local models, and global models. The results are relevant to support decisions made by general QSAR users and regulators, when they have to select and apply one of the analyzed models to predict properties for PBDEs.
Using Local Models to Improve (Q)SAR Predictivity
Authors: Buchwald Fabian , Girschick Tobias , Seeland Madeleine , Kramer Stefan
Published: March 2011

We present a novel (Q)SAR approach that detects groups of structures for local (Q)SAR modeling. The algorithm combines clustering and classification or regression for making predictions on chemical structure data. A clustering procedure producing clusters with shared structural scaffolds is applied as a preprocessing step, before a (local) model is learned for each relevant cluster. Instead of using only one global model (classical approach), we use weighted local models for predictions of query compounds dependent on cluster memberships. The approach is evaluated and compared against standard statistical (Q)SAR algorithms on various datasets. The results show that in many cases the application of local models significantly improves the predictive power of the derived (Q)SAR models compared to the classical approach, to models that are induced by a fingerprint‐based or a hierarchical clustering approach and to locally weighted learning.
Cross‐relaxation imaging of human articular cartilage
Authors: Stikov Nikola , Keenan Kathryn E. , Pauly John M. , Smith R. Lane , Dougherty Robert F. , Gold Garry E.
Published: March 2011

In this article, cross‐relaxation imaging is applied to human ex vivo knee cartilage, and correlations of the cross‐relaxation imaging parameters with macromolecular content in articular cartilage are reported. We show that, unlike the more commonly used magnetization transfer ratio, the bound pool fraction, the cross‐relaxation rate (k) and the longitudinal relaxation time (T1) vary with depth and can therefore provide insight into the differences between the top and bottom layers of articular cartilage. Our cross‐relaxation imaging model is more sensitive to macromolecular content in the top layers of cartilage, with bound pool fraction showing moderate correlations with proteoglycan content, and k and T1 exhibiting moderate correlations with collagen. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
On the cardinality constrained matroid polytope
Authors: Maurras Jean François , Stephan Rüdiger
Published: March 2011

Given a combinatorial optimization problem Π and an increasing finite sequence c of natural numbers, we obtain a cardinality constrained version Πc of Π by permitting only those feasible solutions of Π whose cardinalities are members of c. We are interested in polyhedra associated with those problems, in particular in inequalities that cut off solutions of forbidden cardinality. Maurras [9] and Camion and Maurras [1] introduced a family of inequalities, that we call forbidden set inequalities, which can be used to cut off those solutions. However, these inequalities are in general not facet defining for the polyhedron associated with Πc. In [7] it was shown how one can combine integer characterizations for cycle and path polytopes and a modified form of forbidden set inequalities to give facet defining integer representations for the cardinality restricted versions of these polytopes. Motivated by this work, we apply the same approach to the matroid polytope. It is well known that the so‐called rank inequalities together with the nonnegativity constraints provide a complete linear description of the matroid polytope (see Edmonds [3]). By essentially adding the forbidden set inequalities in an appropriate form, we obtain a complete linear description of the cardinality constrained matroid polytope which is the convex hull of the incidence vectors of those independent sets that have a feasible cardinality. Moreover, we show how the separation problem for the forbidden set inequalities can be reduced to that for the rank inequalities. We also give necessary and sufficient conditions for a forbidden set inequality to be facet defining. © 2011 Wiley Periodicals, Inc. NETWORKS, 2011
A note on Steiner tree games
Authors: Skorin‐Kapov Darko , Skorin‐Kapov Jadranka
Published: March 2011

We investigate the cost allocation strategy associated with the problem of providing some service of common interest from some source to a number of network users, via the minimum cost directed Steiner tree (ST) network that spans the source and all the receivers. The cost of such ST is distributed among its receivers who may be individuals or organizations with possibly conflicting interests. The objective of this article is to develop a reasonably fair and efficient cost allocation scheme associated with the above cost allocation problem. Since finding the optimal Steiner tree is an NP‐hard problem, the input to our cost allocation problem is the best known Steiner tree obtained using some heuristic. To allocate the cost of this Steiner tree to the users (receiver nodes), we formulate the associated Modified Steiner Tree Network (MSTN) game in characteristic function form. Then we construct a primal‐dual cost allocation algorithm which finds some points in the core of the MSTN game and thus results in subsidy‐free cost allocations. Moreover, for the given Steiner tree, our cost allocation scheme is efficient and finds the above “fair” cost allocations in polynomial time. © 2011 Wiley Periodicals, Inc. NETWORKS, 2012
Three‐dimensional numerical modelling by XFEM of spring‐layer imperfect curved interfaces with applications to linearly elastic composite materials
Authors: Zhu Q.‐Z. , Gu S.‐T. , Yvonnet J. , Shao J.‐F. , He Q.‐C.
Published: March 2011

The spring‐layer interface model is widely used in describing some imperfect interfaces frequently involved in materials and structures. Typically, it is appropriate for modelling a thin soft interphase layer between two relatively stiff bulk media. According to the spring‐layer interface model, the displacement vector suffers a jump across an interface whereas the traction vector is continuous across the same interface and is, in the linear case, proportional to the displacement vector jump. In the present work, an efficient three‐dimensional numerical approach based on the extended finite element method is first proposed to model linear spring‐layer curved imperfect interfaces and then applied to predict the effective elastic moduli of composites in which such imperfect interfaces intervene. In particular, a rigorous derivation of the linear spring‐layer interface model is provided to clarify its domain of validity. The accuracy and convergence rate of the elaborated numerical approach are assessed via benchmark tests for which exact analytical solutions are available. The computated effective elastic moduli of composites are compared with the relevant analytical lower and upper bounds. Copyright © 2011 John Wiley & Sons, Ltd.
Plerixafor plus granulocyte‐colony stimulating factor for autologous hematopoietic stem cell mobilization in patients with metastatic neuroblastoma
Authors: Modak Shakeel , Cheung Irene Y. , Kushner Brian H. , Kramer Kim , Reich Lilian , Cheung Nai‐Kong V.
Published: March 2011

Current therapies for high‐risk neuroblastoma (NB) necessitate the availability of several aliquots of autologous peripheral blood stem cells to reverse‐associated myelosuppression. Priming with the CXCR4 inhibitor plerixafor plus G‐CSF was associated with successful stem cell harvest in 5/7 heavily prior‐treated patients with stage 4 NB who had previously failed G‐CSF priming. Minimal residual disease was not detected in harvested cells from any patient despite the presence of disease in bone/bone marrow in 6/7. Hematopoietic reconstitution was achieved in all three patients receiving plerixafor‐primed stem cells after myeloablative therapy. Plerixafor is an effective and safe agent for stem cell collection in patients with NB. Pediatr Blood Cancer 2012; 58: 469–471. © 2011 Wiley Periodicals, Inc.
Prenatal diagnosis of fetal congenitally corrected transposition of the great arteries
Authors: Zhang Ying , Cai Ailu , Sun Wei , Guo Yajun , Zhao Yili
Published: March 2011

Background

Fetal congenitally corrected transposition of the great arteries (ccTGA) is a rare cardiac anomaly and the diagnosis remains a challenge for many sonographers in routine screening programs. We describe a new method of diagnosis by four‐dimensional (4D) echocardiography and spatiotemporal image correlation (STIC).

Methods

We reviewed retrospectively 11 cases of fetal ccTGA complicated with ventricular septal defect. The four‐chamber view (4CV) and the cardiac outflow tract views were obtained by conventional two‐dimensional (2D) echocardiography. Atrioventricular connections were observed in the 4CV and ventriculoarterial connections in the cardiac outflow tract views. 4D volume data sets were acquired at the 4CV level and then analyzed by STIC. All volume data sets were displayed using the multiplanar modality, which allows simultaneous display of images in three orthogonal planes. The correlation of the three planes was used to reveal the spatial relationship of the two great arteries. The diagnosis was confirmed by postnatal echocardiography or by autopsy.

Results

By 4D echocardiography and STIC, the origin, course and relationship of the two great arteries could be revealed by moving the reference dot in the three correlated orthogonal planes: in ccTGA, the aorta could be seen to arise from the right ventricle, anterior and to the left of the pulmonary artery, and its course was upward and parallel to the pulmonary artery.

Conclusions

4D echocardiography and STIC technique can assist 2D echocardiography in the diagnosis of ccTGA by revealing the spatial relationship of the transposed great arteries, improving the understanding of the anomaly and facilitating the examination. Copyright © 2011 John Wiley & Sons, Ltd.
Placental site in the second trimester of pregnancy and its association with subsequent obstetric outcome
Authors: Fung Tak Yuen , Sahota Daljit Singh , Lau Tze Kin , Leung Tak Yeung , Chan Lin Wai , Chung Tony Kwok Hung
Published: March 2011

Objective

To determine if placental location in the second trimester of pregnancy is associated with adverse pregnancy outcomes.

Methods

We performed a retrospective study on 16 236 patients having ultrasound examination at 14 to 23 weeks of gestation between 2000 and 2007. The placental location was classified into one of four groups: ‘central’, ‘fundal’, ‘lateral’ and ‘covering Os’. Obstetric outcomes of non‐central placenta were compared to those with ‘central’ placenta.

Results

Women with a ‘fundal’ placenta were at increased risk of developing pre‐eclampsia (PET) (odds ratios (OR) = 2.27; 95% confidence intervals (CI), 1.31–3.93), a preterm delivery before 34 weeks (OR = 2.23; 95% CI, 1.18–4.22), a non‐vertex presentation (OR = 3.48; 95% CI, 2.49–4.86), undergoing a manual removal of placenta (MROP) following a vaginal delivery (OR = 7.1; 95% CI, 4.24–11.85) and small for gestational age (SGA) (OR = 1.35; 95% CI, 1.03–1.79). Women with a ‘lateral’ placenta were at increased risk of developing PET (OR = 2.04; 95% CI, 1.28–3.25), spontaneous preterm delivery before 34 weeks (OR = 2.04; 95% CI, 1.04–3.98), MROP (OR = 6.75; 95% CI, 4.4–10.33) and SGA (OR = 1.82; 95% CI, 1.48–2.23). Five women with a ‘cover Os’ placenta had an increased risk of postpartum haemorrhage (>1000 mL) (OR = 6.18; 95% CI 2.29–16.65) if they had a vaginal delivery.

Conclusion

Non‐central placental location in the second trimester is associated with an increase risk of adverse obstetric outcome. Copyright © 2011 John Wiley & Sons, Ltd.
Dual thermo‐ and pH‐sensitive network‐grafted hydrogels formed by macrocrosslinker as drug delivery system
Authors: Pan Ting‐Ting , He Wei‐Dong , Li Li‐Ying , Jiang Wen‐Xing , He Chen , Tao Jing
Published: March 2011

Dual thermo‐ and pH‐sensitive network‐grafted hydrogels made of poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA) network and poly(N‐isopropylacrylamide) (PNIPAM) grafting chains were successfully synthesized by the combination of atom transfer radical polymerization (ATRP), reversible addition‐fragmentation chain transfer (RAFT) polymerization, and click chemistry. PNIPAM having two azide groups at one chain end [PNIPAM‐(N3)2] was prepared with an azide‐capped ATRP initiator of N,N‐di(β‐azidoethyl) 2‐chloropropionylamide. Alkyne‐pending poly(N,N‐dimethylaminoethyl methacrylate‐co‐propargyl acrylate) [P(DMAEMA‐co‐ProA)] was obtained through RAFT copolymerization using dibenzyltrithiocarbonate as chain transfer agent. The subsequent click reaction led to the formation of the network‐grafted hydrogels. The influences of the chemical composition of P(DMAEMA‐co‐ProA) on the properties of the hydrogels were investigated in terms of morphology and swelling/deswelling kinetics. The dual stimulus‐sensitive hydrogels exhibited fast response, high swelling ratio, and reproducible swelling/deswelling cycles under different temperatures and pH values. The uptake and release of ceftriaxone sodium by these hydrogels showed both thermal and pH dependence, suggesting the feasibility of these hydrogels as thermo‐ and pH‐dependent drug release devices. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Structural physiology based on electron crystallography
Authors: Fujiyoshi Yoshinori
Published: March 2011

There are many questions in brain science, which are extremely interesting but very difficult to answer. For example, how do education and other experiences during human development influence the ability and personality of the adult? The molecular mechanisms underlying such phenomena are still totally unclear. However, technological and instrumental advancements of electron microscopy have facilitated comprehension of the structures of biological components, cells, and organelles. Electron crystallography is especially good for studying the structure and function of membrane proteins, which are key molecules of signal transduction in neural and other cells. Electron crystallography is now an established technique to analyze the structures of membrane proteins in lipid bilayers, which are close to their natural biological environment. By utilizing cryo‐electron microscopes with helium cooled specimen stages, which were developed through a personal motivation to understand functions of neural systems from a structural point of view, structures of membrane proteins were analyzed at a resolution higher than 3 Å. This review has four objectives. First, it is intended to introduce the new research field of structural physiology. Second, it introduces some of the personal struggles, which were involved in developing the cryo‐electron microscope. Third, it discusses some of the technology for the structural analysis of membrane proteins based on cryo‐electron microscopy. Finally, it reviews structural and functional analyses of membrane proteins.
Monitoring the conformational changes of an intrinsically disordered peptide using a quartz crystal microbalance
Authors: Shur Oren , Wu Jun , Cropek Donald M. , Banta Scott
Published: March 2011

Intrinsically disordered peptides (IDPs) have recently garnered much interest because of their role in biological processes such as molecular recognition and their ability to undergo stimulus‐responsive conformational changes. The block V repeat‐in‐toxin motif of the Bordetella pertussis adenylate cyclase is an example of an IDP that undergoes a transition from a disordered state to an ordered beta roll conformation in the presence of calcium ions. In solution, a C‐terminal capping domain is necessary for this transition to occur. To further explore the conformational behavior and folding requirements of this IDP, we have cysteine modified three previously characterized constructs, allowing for attachment to the gold surface of a quartz crystal microbalance (QCM). We demonstrate that, while immobilized, the C‐terminally capped peptide exhibits similar calcium‐binding properties to what have been observed in solution. In addition, immobilization on the solid surface appears to enable calcium‐responsiveness in the uncapped peptides, in contrast to the behavior observed in solution. This work demonstrates the power of QCM as a tool to study the conformational changes of IDPs immobilized on surfaces and has implications for a range of potential applications where IDPs may be engineered and used including protein purification, biosensors, and other bionanotechnology applications.