bluuebunny/crossref_metadata_2025_split huggingface dataset:
5‐Cyanotetrazolate as a Ligand and Linker in Copper(II) Complexes and Coordination Polymers
Authors: Szafranowska Barbara , Beck Johannes 
Published: May 2013

Abstract5‐Cyanotetrazole readily forms from (CN)2 and HN3. The coordination abilities of the 5‐cyanotetrazolate anion N4CCN– (ctz) towards CuII ions were examined and a series of complexes and coordination polymers were synthesized and characterized by single‐crystal structure analyses: PPh4[Cu(ctz)3] (1), [Cu(ctz)2(bipy)] (2, bipy = 2,2′‐bipyridine), [CuCl(py)4](ctz)·2py (3, py = pyridine), [Cu2(ctz)6Cu(CH3CN)2(H2O)2]·2CH3CN (4a), [Cu2(ctz)6Cu(H2O)3{(CH3)2CO}]·3(CH3)2CO (4b), [Cu(ctz)2(py)4] (5), [Cu2(ctz)4(bipy)2] (6) and [Cu2(ctz)2(tpm)2(NO3)]NO3 [7, tpm = tris(pyrazol‐1‐yl)methane]. As ctz is a multidentate linker, additional neutral coligands such as monodentate py, bidentate bipy and tridentate tpm ligands were used to avoid the formation of noncrystalline polymers. The structures of 1–7 reflect the versatile coordination abilities of ctz in the various types of coordination environments of the CuII ions and dimensionalities of the linkages. The structures represent 1D chain motifs (1, 2 and 3), 2D layered structures (4a and 4b), mononuclear (5) and dinuclear complexes (6 and 7). Magnetic coupling phenomena were detected by susceptibility measurements of 1, 4a, 6 and 7, which were fitted to the magnetic models according to antiferromagnetic spin‐pairing of two S = 1/2 systems (Bleaney–Bowers) for 6 (J = –0.53 cm–1) and 7 (J = –2.91 cm–1), to the ferromagnetic high‐temperature series expansion based on the Baker 1D (S = 1/2) chain model for 1 (J = +14.4 cm–1) and to the Néel model of ferrimagnetism for 4a. The diverse magnetic interactions between the Cu2+ sites are communicated by the bridging ctz anions.
Short Synthetic Route to Benzaldehyde‐Functionalized Idose and Talose Derivatives by Acetoxonium Ion Rearrangements
Authors: Kopitzki Sebastian , Thiem Joachim 
Published: May 2013

AbstractCarbohydrate–carbohydrate interactions (CCI) are mediated by complexation of metal ions. Angyal postulated on the requirements for hydroxy group arrangement in pyranoses to account for metal‐ion complexation. These requirements are particularly well fulfilled in α‐ido‐ and α‐talopyranosides, whose ring hydroxy groups have all axial and axial‐equatorial‐axial configurations, respectively. Surface plasmon resonance (SPR) and gold‐nanoparticle techniques have proved to be powerful tools to investigate CCIs. Benzaldehyde‐functionalized glycans can be used for attachment to both gold nanoparticles and SPR sensor surfaces. Therefore, benzaldehyde‐equipped ido‐ and talopyranosides were synthesized by the almost forgotten Paulsen acetoxonium rearrangement. This approach provides peracetylated idose and talose in only two steps from common glucose and galactose precursors, respectively, in overall yields of up to 41 % and, therefore, avoids long and laborious procedures to obtain these rare carbohydrates. The derivatives are being used in ongoing CCI studies using SPR to test Angyal's postulate about the structural requirements for hydroxy group arrangements.
A Route to 2‐Alkenyl‐3‐(tert‐butyldiphenylsilyl)amines and Application to the Construction of a Tricyclic Ring System
Authors: Yadav Veejendra K. , Narhe Bharat D. , Kumar Kamlesh , Hulikal Vijaykumar 
Published: May 2013

AbstractN‐Tosyl 3,3‐dialkyl‐2‐(tert‐butyldiphenylsilylmethyl)azetidines rearrange smoothly into the corresponding 2‐alkenyl‐3‐(tert‐butyldiphenylsilyl)amines upon exposure to BF3·OEt2 in CH2Cl2. The reaction involves sequential σC–N bond cleavage, 1,2‐migration of the N‐tosyl‐aminomethyl group, and deprotonation of the resultant tert‐carbenium ions. For the instance in which the carbenium ion formed from migration of the N‐tosyl‐aminomethyl group is highly stable by virtue of being, for example, tertiary as well as benzylic, the migration takes place in sync with σC–N bond cleavage, which leads to high configurational control at the tert‐butyldiphenylsilylmethyl‐bearing carbon atom in the product.
A Ferrocene‐Tagged Amyloid‐β Fragment for Rapid Screening of Aggregation Inhibitors from Natural Compounds by HPLC‐Electrochemical Detection
Authors: Zhang Lin , Kai Tianhan , Sun Zhifang , Hao Yuanqiang , Tu Qiuyun , Zhou Feimeng 
Published: May 2013

AbstractAggregates of amyloid beta (Aβ) peptides are believed to be responsible for the neuropathology of Alzheimer’s disease. In this work, ferrocene (Fc) is attached to the aggregating core of the Aβ peptides, KLVFFAE. Inhibition of Fc‐KLVFFAE aggregation by curcumin, a natural compound, was monitored by HPLC‐electrochemical detection (HPLC‐EC). The Fc oxidation current is dependent on the incubation condition and curcumin can retain Fc‐KLVFFAE in its monomeric form. We demonstrate that tagging Fc to KLVFFAE affords a cost‐effective and electroactive mimicry of Aβ(142) and HPLC‐EC is suitable for sensitive, reproducible, and facile screening of drugs for inhibiting the aggregation of Aβ peptides.
Trabecular Homogeneity Index Derived From Plain Radiograph to Evaluate Bone Quality
Authors: Thevenot Jérôme , Hirvasniemi Jukka , Finnilä Mikko , Pulkkinen Pasi , Kuhn Volker , Link Thomas , Eckstein Felix , Jämsä Timo , Saarakkala Simo 
Published: May 2013

Abstract

Radiographic texture analysis has been developed lately to improve the assessment of bone architecture as a determinant of bone quality. We validate here an algorithm for the evaluation of trabecular homogeneity index (HI) in the proximal femur from hip radiographs, with a focus on the impact of the principal compressive system of the trabecular bone, and evaluate its correlation with femoral strength, bone mineral density (BMD), and volumetric trabecular structure parameters. A semiautomatic custom-made algorithm was applied to calculate the HI in the femoral neck and trochanteric areas from radiographs of 178 femoral bone specimens (mean age 79.3 ± 10.4 years). Corresponding neck region was selected in CT scans to calculate volumetric parameters of trabecular structure. The site-specific BMDs were assessed from dual-energy X-ray absorptiometry (DXA), and the femoral strength was experimentally tested in side-impact configuration. Regression analysis was performed between the HI and biomechanical femoral strength, BMD, and volumetric parameters. The correlation between HI and failure load was R2 = 0.50; this result was improved to R2 = 0.58 for cervical fractures alone. The discrimination of bones with high risk of fractures (load &lt;3000 N) was similar for HI and BMD (AUC = 0.87). Regression analysis between the HIs versus site-specific BMDs yielded R2 = 0.66 in neck area, R2 = 0.60 in trochanteric area, and an overall of R2 = 0.66 for the total hip. Neck HI and BMD correlated significantly with volumetric structure parameters. We present here a method to assess HI that can explain 50% of an experimental failure load and determines bones with high fracture risk with similar accuracy as BMD. The HI also had good correlation with DXA and computed tomography–derived data. © 2013 American Society for Bone and Mineral Research.
Siglec-15 Regulates Osteoclast Differentiation by Modulating RANKL-Induced Phosphatidylinositol 3-Kinase/Akt and Erk Pathways in Association With Signaling Adaptor DAP12
Authors: Kameda Yusuke , Takahata Masahiko , Komatsu Miki , Mikuni Shintaro , Hatakeyama Shigetsugu , Shimizu Tomohiro , Angata Takashi , Kinjo Masataka , Minami Akio , Iwasaki Norimasa 
Published: May 2013

Abstract

Siglecs are a family of sialic acid–binding immunoglobulin-like lectins that regulate the functions of cells in the innate and adaptive immune systems through glycan recognition. Here we show that Siglec-15 regulates osteoclast development and bone resorption by modulating receptor activator of nuclear factor κB ligand (RANKL) signaling in association with DNAX-activating protein 12 kDa (DAP12), an adaptor protein bearing an immunoreceptor tyrosine-based activation motif (ITAM). Among the known Siglecs expressed in myeloid lineage cells, only Siglec-15 was upregulated by RANKL in mouse primary bone marrow macrophages. Siglec-15–deficient mice exhibit mild osteopetrosis resulting from impaired osteoclast development. Consistently, cells lacking Siglec-15 exhibit defective osteoclast development and resorptive activity in vitro. RANKL-induced activation of phosphatidylinositol 3-kinase (PI3K)/Akt and Erk pathways were impaired in Siglec-15–deficient cells. Retroviral transduction of Siglec-15–null osteoclast precursors with wild-type Siglec-15 or mutant Siglec-15 revealed that the association of Siglec-15 with DAP12 is involved in the downstream signal transduction of RANK. Furthermore, we found that the ability of osteoclast formation is preserved in the region adjacent to the growth plate in Siglec-15–deficient mice, indicating that there is a compensatory mechanism for Siglec-15–mediated osteoclastogenesis in the primary spongiosa. To clarify the mechanism of this compensation, we examined whether osteoclast-associated receptor (OSCAR)/Fc receptor common γ (FcRγ) signaling, an alternative ITAM-mediated signaling pathway to DAP12, rescues impaired osteoclastogenesis in Siglec-15–deficient cells. The ligands in type II collagen activate OSCAR and rescue impaired osteoclastogenesis in Siglec-15–deficient cells when cultured on bone slices, indicating that Siglec-15–mediated signaling can be compensated for by signaling activated by type II collagen and other bone matrix components in the primary spongiosa. Our findings indicate that Siglec-15 plays an important role in physiologic bone remodeling by modulating RANKL signaling, especially in the secondary spongiosa. © 2013 American Society for Bone and Mineral Research.
Petrological modeling of basaltic rocks from Venus: A case for the presence of silicic rocks
Authors: Shellnutt J. Gregory 
Published: May 2013

AbstractThe presence of highly evolved igneous rocks on Venus is a controversial issue. The formations of highland terranes and pancake domes are the two principal tectonic and volcanic features which argue in favor of the presence of silicic igneous rocks; however, the lack of water on Venus casts doubt on whether or not granites and rhyolites can form. Data returned to Earth from the Venera 13 and 14 landers show that the surface of Venus is composed of basaltic rocks similar in composition to those found on Earth. Here it is shown that anhydrous and hydrous fractional crystallization modeling using the Venera 13 and 14 data as starting materials can produce compositions similar to terrestrial phonolites and rhyolites. It is suggested that at shallow crustal levels (i.e., ≤ 0.1 GPa), mafic magmas can differentiate into silicic magmas resembling phonolites or rhyolites which may or may not erupt. Furthermore, the hydrous equilibrium partial melting models can produce rocks similar to terrestrial andesites and rhyolites, whereas anhydrous models suggest that there may be a uniquely Venusian type of silicic rock. The silicic rocks, if present, could act as “continental nucleation” sites and/or their presence may facilitate preferential sites of shearing and deformation of the Venusian crust.
Crushed rephased orthogonal slice selection (CROSS) for simultaneous acquisition of two orthogonal proton resonance frequency temperature maps
Authors: Krafft Axel J. , Rauschenberg Jaane , Maier Florian , Jenne Jürgen W. , Bock Michael 
Published: May 2013

PurposeTo evaluate a novel imaging sequence termed crushed rephased orthogonal slice selection (CROSS) that uses the available time in long echo time (TE) gradient echo (GRE) imaging—as employed for proton resonance frequency (PRF) shift thermometry—to simultaneously acquire two orthogonal magnetic resonance imaging (MRI) temperature maps around the target region.Materials and MethodsThe CROSS sequence encodes a second orthogonal slice between excitation and data readout in long‐TE imaging and applies dedicated crusher (CR) gradients to separate the signals from the two slices. Numerical simulations of the Bloch equations and phantom experiments were performed to analyze the MR signal. In phantom and in vivo experiments with two domestic pigs, the applicability of the CROSS sequence for temperature mapping of thermal therapies with focused ultrasound and laser was studied.ResultsA successful separation of the signals from the two slices was achieved for CR dephasing lengths approaching the in‐plane resolution. In the two animal experiments, CROSS temperature mapping could be successfully demonstrated at a temporal resolution of 2–3 seconds and a temperature uncertainty of 3–4K.ConclusionAt the expense of a reduced signal in the overlap of the two slices, the CROSS sequence achieves an improvement of temporal resolution by 50%, without requiring further acceleration techniques such as parallel imaging, over conventional sequential GRE sequences employing the same repetition time as the CROSS sequence acquires two slices within one repetition interval. J. Magn. Reson. Imaging 2013;38:1510–1520. © 2013 Wiley Periodicals, Inc.
Prognostic value of the D‐dimer test in oesophageal cancer during the perioperative period
Authors: Diao Dongmei , Zhu Kun , Wang Zhe , Cheng Yao , Li Kang , Pei Leilei , Dang Chengxue 
Published: May 2013

AbstractBackgroundThere has been little research on the perioperative D‐dimer levels in oesophageal cancer patients. Plasma D‐dimer levels can be used to predict the outcome in cancer patients.MethodsA cancer group of 66 oesophageal cancer patients and a control group of 12 patients with benign disease were enrolled in this cohort study. The plasma D‐dimer levels during the pre‐operation and 3rd and 9th day post‐operation periods were prospectively examined and analysed between the two groups. Plasma D‐dimer levels were also compared with the clinicopathological characteristics and 3‐year survival of the oesophageal cancer patients.ResultsPlasma D‐dimer levels increased in both groups after surgery, but they were significantly higher in the cancer group. In oesophageal cancer patients, pre‐operation plasma D‐dimer levels were significantly higher in TNM stage IV patients. Perioperative plasma D‐dimer levels significantly increased after surgery, and the survival was shortened in those patients whose D‐dimer levels on the 3rd and 9th post‐operative day above the median. In addition, increased plasma D‐dimer levels at the 3rd and 9th days after surgery were influenced by the patient's age.ConclusionIn oesophageal cancer patients, D‐dimer levels increased after surgery, and the increases were associated with poor outcomes. J. Surg. Oncol. 2013 108:34–41. © 2013 Wiley Periodicals, Inc.
The Role of Shape and Size of Guest Molecules in the Formation of Clathrates and Intercalates of Syndiotactic Polystyrene
Authors: Tarallo Oreste , Auriemma Finizia , de Ballesteros Odda Ruiz , Di Girolamo Rocco , Diletto Claudia , Malafronte Anna , De Rosa Claudio 
Published: May 2013

AbstractThe crystal structure of syndiotactic polystyrene (sPS) co‐crystals of δ‐class is discussed with the aim of identifying molecular descriptors that allow predicting the lattice distortions induced by the inclusion of guest molecules inside the cavities of the nanoporous δ‐form. Based on the consideration that monoclinic and triclinic clathrates and intercalates of sPS form as a result of the unique deformability of the cavities of the δ‐form, the identified parameters are the fractional occupancy factors of the undeformed cavity of the δ‐form from guests along the a‐axis, the c‐axis, and the normal to the (010) planes of the crystals, and the relative orientation of the guests to the chain axes.magnified image
Association between baseline fetal hemoglobin levels and incidence of severe vaso‐occlusive pain episodes in children with sickle cell anemia
Authors: Bhatnagar Pallav , Keefer Jeffrey R. , Casella James F. , Barron‐Casella Emily A. , Bean Christopher J. , Hooper Craig W. , Payne Amanda B. , Arking Dan E. , Debaun Michael R. 
Published: May 2013

AbstractThe ameliorating effect of high fetal hemoglobin (HbF) levels on the incidence of pain episodes in sickle cell anemia (SCA) is well‐known; however, in children this relationship is less clearly established. We hypothesized that higher HbF levels in children with SCA are associated with fewer severe pain episodes. A meta‐analysis of data from the Silent Infarct Transfusion Trial (n = 456) and the Cooperative Study of Sickle Cell Disease (n = 764), demonstrated that baseline HbF levels were associated with the incidence of severe pain, commonly defined across studies as an event requiring hospitalization (P‐value = 0.02). Pediatr Blood Cancer 2013;60:E125–E127. © 2013 Wiley Periodicals, Inc.
The role of noninvasive prenatal testing as a diagnostic versus a screening tool – a cost‐effectiveness analysis
Authors: Ohno Mika , Caughey Aaron 
Published: May 2013

ABSTRACTObjectiveAs the sensitivity and specificity of noninvasive prenatal testing (NIPT) that uses cell‐free fetal DNA in maternal serum to identify Down syndrome (DS) in utero improves, NIPT could be considered a diagnostic test, thus avoiding the complications of chorionic villus sampling or amniocentesis. This study investigates the cost‐effectiveness of NIPT as a diagnostic versus a screening tool.MethodA decision‐analytic model compared NIPT as a diagnostic tool (NIPT Dx) that did not require a confirmatory amniocentesis versus NIPT used for screening (NIPT Scr) that allowed a confirmatory amniocentesis for screen positive results. Baseline case, univariate, and multivariate sensitivity analyses were performed.ResultsFor a high‐risk population, NIPT Dx would result in three more DS babies born and 2432 more elective terminations compared with NIPT Scr. Furthermore, there would be many more terminations of fetuses without DS with NIPT Dx (2424) than procedure‐related losses associated with NIPT Scr (29). NIPT Scr is more expensive but cost‐effective at $7687 per quality‐associated life year (QALY), less than the standard cost‐effectiveness limit of $100 000/QALY.ConclusionsNoninvasive prenatal testing as a screening tool that requires a confirmatory amniocentesis is cost‐effective compared with its use as a diagnostic tool and leads to far fewer losses of normal pregnancies. © 2013 John Wiley & Sons, Ltd.
Euglycaemic ketoacidosis in patients with and without diabetes
Authors: Le Neveu Francine , Hywel Brython , Harvey John N 
Published: May 2013

AbstractKetoacidosis in individuals with diabetes is usually associated with a raised plasma glucose concentration. However, ketoacidosis in diabetes can occur with normal (≤11mmol/L) plasma glucose levels. Ketoacidosis is also seen in patients who do not have diabetes, most commonly in pregnancy or following alcoholic binges, rarely with starvation, anorexia nervosa or inborn errors of metabolism. The aim of this review is to compare the clinical features, pathophysiology and management of these conditions.Common clinical features due to a raised anion gap metabolic acidosis are seen. Reduced carbohydrate intake is a usual contributor to ketogenesis. Treatment is primarily with intravenous glucose, insulin if there is insulin deficiency and potassium as needed. The value of using bedside monitors to measure β‐hydroxybutyrate levels both for diagnosis and monitoring of response to treatment is emphasised. Early recognition of ketoacidosis and treatment with glucose rather than saline is important for optimum outcome. Copyright © 2013 John Wiley & Sons. Practical Diabetes 2013; 30(4): 167–171
Vinylimidazole‐based asymmetric ion pair comonomers: Synthesis, polymerization studies and formation of ionically crosslinked PMMA
Authors: Jana Satyasankar , Vasantha Vivek Arjunan , Stubbs Ludger Paul , Parthiban Anbanandam , Vancso Julius G. 
Published: May 2013

ABSTRACTVinylimidazole‐based asymmetric ion pair comonomers (IPCs) which are free from nonpolymerizable counter ions have been synthesized, characterized and polymerized by free radical polymerization (FRP), atom transfer radical polymerization (ATRP), and reversible addition‐fragmentation chain transfer (RAFT) mediated polymerizations in solution and by dispersion polymerization in water. The asymmetric nature of IPCs is due to the fact that cationic component of these IPCs is derived from vinylimidazole (VIm) and anionic component is derived from either styrenesulfonate (SS) or 2‐acrylamido‐2‐methyl‐1‐propanesulfonate. Although under ATRP, conversions are either very low or negligible, FRP and RAFT produces polymers with high to moderate monomer conversions but with different solubility characteristics. This investigation provides insight to the polymerization behavior of each component of the asymmetric IPCs and also its effects on composition and solubility characteristics of the resulting polymers. The IPCs studied here are high temperature ionic liquid and thus the polymers synthesized from these IPCs are highly ionic in nature and possess very strong intermolecular interactions which makes some of these IPC based polymers completely insoluble in organic and aqueous solvents. This highly ionic interaction is exploited to synthesize ionically crosslinked PMMA. MMA on copolymerization with 5–6 mol % of IPC yielded copolymer which is insoluble in common organic solvents like THF, DMF, etc., unlike homo PMMA. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3260–3273
Learners' Beliefs as Mediators of What Is Noticed and Learned in the Language Classroom
Authors: Kartchava Eva , Ammar Ahlem 
Published: May 2013

The goal of this study was to determine whether learner beliefs regarding corrective feedback mediate what is noticed and learned in the language classroom. The participants were four groups of high‐beginner college‐level francophone English as a second language learners and their teachers. Each teacher was assigned to a treatment condition that fit his corrective feedback style, and each provided feedback in response to errors with the past tense and questions in the past. Participants (N = 197) completed a beliefs questionnaire, and half (n = 99) took part in the intervention that followed. Beliefs were probed using a 40‐item questionnaire, and average belief scores were calculated for each learner. These were then correlated both with the noticing reported on an immediate recall measure and with the test scores on picture description and spot‐the‐differences tasks. The results reveal four common beliefs, two of which mediated the noticeability of the supplied feedback, but none of which impacted the learning outcomes.
Haptic perception
Authors: Kappers Astrid M.L. , Bergmann Tiest Wouter M. 
Published: May 2013

AbstractFueled by novel applications, interest in haptic perception is growing. This paper provides an overview of the state of the art of a number of important aspects of haptic perception. By means of touch we can not only perceive quite different material properties, such as roughness, compliance, friction, coldness and slipperiness, but we can also perceive spatial properties, such as shape, curvature, size and orientation. Moreover, the number of objects we have in our hand can be determined, either by counting or subitizing. All these aspects will be presented and discussed in this paper. Although our intuition tells us that touch provides us with veridical information about our environment, the existence of prominent haptic illusions will show otherwise. Knowledge about haptic perception is interesting from a fundamental viewpoint, but it also is of eminent importance in the technological development of haptic devices. At the end of this paper, a few recent applications will be presented. WIREs Cogn Sci 2013, 4:357–374. DOI: 10.1002/wcs.1238This article is categorized under:

Psychology > Perception and Psychophysics