bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of commercial implants with nanoindentation defines future development needs for hydroxyapatite coatings
Authors: Gross Kārlis A. , Saber‐Samandari Saeed , Heemann Karina S. 
Published: February 2010

AbstractThe performance of biomedical implants relies on the ability to assess and refine the microstructure of biomaterials. Instrumented nanoindentation was applied to determine the mechanical properties of plasma sprayed hydroxyapatite‐coated implants from different commercial vendors. All biomedical devices contained both amorphous and crystalline phases. Nanoindentation of the amorphous phase revealed a hardness of 1.5 ± 0.3 GPa and an elastic modulus of 48 ± 6 GPa. The crystalline phase revealed a range in hardness of 3.0–7.7 GPa. The large range is attributed to the presence of porosity, surrounding amorphous areas, and hydroxyapatite (unmolten particle cores and recrystallized hydroxyapatite). A selection of the powder type (spray‐dried or sintered) leads to different mechanical properties within the coating. A spray‐dried powder provides a lower hardness and elastic modulus when unmolten particle cores are included in the coating. Meanwhile recrystallized areas are intermediate in hardness. The combination of a polished cross‐section and nanoindentation offers the ability to determine a range of quality control tests including hardness, elastic modulus, bond strength, fracture toughness, substrate and coating roughness, crystallinity, and coating thickness. Property maps determined from nanoindentation will provide a graphical representation of the mechanical property distribution within the coating and provide a basis for coating property refinements. The assessment of commercial coatings is used a basis for discussion of future developments for hydroxyapatite coatings. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Surface modification of titanium and titanium alloys by ion implantation
Authors: Rautray Tapash R. , Narayanan R. , Kwon Tae‐Yub , Kim Kyo‐Han 
Published: February 2010

AbstractTitanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2010
Novel biodegradable composite wound dressings with controlled release of antibiotics: Microstructure, mechanical and physical properties
Authors: Elsner Jonathan J. , Shefy‐Peleg Adaya , Zilberman Meital 
Published: February 2010

AbstractWound dressings aim to restore the milieu required for skin regeneration and protect the wound from environmental threats, including penetration of bacteria. The dressings should be easy to apply and remove and maintain a moist healing environment. In this study, novel biodegradable composite wound dressings based on a polyglyconate mesh and a porous PDLGA binding matrix were developed and studied. These novel dressings were prepared by dip‐coating woven meshes in inverted emulsions, followed by freeze‐drying. Their investigation focused on the microstructure, mechanical and physical properties, and the release profile of the antibiotic drug ceftazidime from the binding matrix. The mechanical properties of our wound‐dressing structures were found to be superior, combining relatively high tensile strength and ductility, which changed only slightly during 3 weeks of incubation in an aqueous medium. The parameters of the inverted emulsion, the organic–aqueous phase ratio, and the type of surfactant used for stabilizing the emulsion were found to affect the microstructure of the binding matrix and the resulting properties, i.e., water absorbance, water vapor transmission rate, and drug‐release profile from the binding matrix. Appropriate selection of these parameters can yield composite structures that have the desired physical properties and drug release behavior. Thus, these unique structures are potentially very useful as burn and ulcer dressings. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010
Premixed acidic calcium phosphate cement: Characterization of strength and microstructure
Authors: Aberg J. , Brisby H. , Henriksson H. B. , Lindahl A. , Thomsen P. , Engqvist H. 
Published: February 2010

AbstractBy using a premixed calcium phosphate cement (CPC), the handling properties of the cement are drastically improved, which is a challenge for traditional injectable CPCs. Previously premixed cements have been based on apatitic cements. In this article, acidic cement has been developed and evaluated. Monocalcium phosphate monohydrate and β‐tricalcium phosphate were mixed with glycerol to form a paste. As the paste does not contain water, no setting reaction starts and thus the working time is indefinite. Powder/liquid ratios (P/L) of 2.25, 3.5 and 4.75 were evaluated. Setting time (ST) and compressive strength (CS) were measured after 1 day, 1 week and 4 weeks in phosphate buffered saline (PBS) solution, and the corresponding microstructure was evaluated using electron microscopy and X‐ray diffraction. The ST started when the cements were placed in PBS and ranged from 28 to 75 min, higher P/L gave a lower ST. Higher P/L also gave a higher CS, which ranged from 2 to 16 MPa. The microstructure mainly consisted of monetite, 1–5 μm in grain size. After 4 weeks in PBS, the strength increased. As acidic cements are resorbed faster in vivo, this cement should allow faster bone regeneration than apatitic cements. Premixed cements show a great handling benefit when compared with normal CPCs and can be formulated with similar ST and mechanical properties. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2010
Relaxed energetic maps of κ‐carrabiose: A DFT study
Authors: Yousfi N. , Sekkal‐Rahal M. , Sayede A. , Springborg M. 
Published: February 2010

AbstractThe B3LYP density function was used with the 6‐31G(d) basis set to perform relaxed energetic contour maps of the charged form of κ‐carrabiose in the gas phase and for the neutral form first in the gas phase and then by simulating the presence of water as solvent using the Onsager model. Only one starting conformation has been considered to perform all the calculations. Rigid energetic maps have been then constructed either by addition of diffuse or polarization functions to the basis set obtaining in that way 6‐31+G(d)//6‐31G(d), 6‐31+G(d,p)//6‐31G(d), and 6‐311++G(d,p)//6‐31G(d) energetic maps that have been carefully examined. The obtained structures corresponding to the lower energy conformers have been then fully optimized using different basis sets with the B3LYP method, a reversion in term of energy has been observed for the two first minima in the case of the charged disaccharide in the gas phase, this was attributed to the large grid of 30° that could lead to the exclusion of an intermediate value corresponding to the real minimum of energy. We thus suggest that after establishing potential energy maps it is essential to proceed to full optimizations of the lower energy conformers. Calculations using the more accurate correlated method MP2 with the 6‐31G(d) basis set have also been performed for conformers of the two disaccharides in the gas phase. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010
Role of sonography in the emergency room to diagnose sternal fractures
Authors: You Je Sung , Chung Yong Eun , Kim Donghyun , Park Saehwan , Chung Sung Pil 
Published: February 2010

AbstractBackground.The diagnosis of a sternal fracture is often difficult when the fracture site shows only minimal displacement on conventional radiography. Recently, sonography (US) has been used widely in the emergency room (ER). We investigated the diagnostic performance of US in the ER for the diagnosis of sternal fractures.Method.Thirty‐six consecutive patients examined for pain and tenderness in the sternum after blunt chest trauma were enrolled in the study. Antero‐posterior and lateral radiographs and sonograms of the sternum were obtained within 24 hours after admission. The 2 imaging modalities were interpreted in a blinded manner and their diagnostic sensitivity and specificity were calculated. The final diagnosis was based on results from the clinical examination, radiographs, and sonograms.Result.Twenty‐four of the 36 patients were diagnosed with sternal fractures. The sensitivity and specificity of the plain radiographs were 70.8% (95% CI = 56.0–85.6%) and 75.0% (95% CI = 60.9–89.1%), respectively. In contrast, sonography had a 100% sensitivity and specificity (95% CI = 90.3–100%).Conclusion.US has a higher sensitivity and specificity in diagnosing sternal fractures than conventional radiographs. US should be considered in patients with symptoms suggesting sternal fractures whose radiographs remain indeterminate. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound, 2010
Further observations on the empty “amnion sign”
Authors: Yegul N. Tugce , Filly Roy A. 
Published: February 2010

AbstractObjective.To assess the positive predictive value of the empty “amnion sign” (visualization of an amnion without concomitant visualization of an embryo) for the diagnosis of early pregnancy failure.Methods.Retrospective study of 882 1st trimester sonographic examinations with abnormal findings among women who were threatening to abort. Eight hundred six met the inclusion criteria.Results.In the study cohort 286 (35.5%) had no identifiable embryo and 71 of those without an identifiable embryo had a visible amnion (24.8%). The breakdown of the mean sac diameter of the study cohort was as follows: those measuring less than 16 mm (n = 16); those measuring 16–20 mm (n = 20); those measuring 21 mm or more (n = 35). Sixty‐eight of the 71 patients had adequate follow‐up. Pregnancy failure was confirmed in all 68 patients (positive predictive value = 100%).Conclusions.The data from this study indicate that visualization of an amnion without concomitant visualization of an embryo (the empty “amnion sign”) confirms pregnancy failure regardless of the mean sac diameter and with a sufficiently high positive predictive value to make a definitive diagnosis. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound, 2010
Personality and teamwork behavior in context: The cross‐level moderating role of collective efficacy
Authors: Tasa Kevin , Sears Greg J. , Schat Aaron C. H. 
Published: February 2010

AbstractThis research examines whether the relationship between an individual's personality and their behavior within a team is contingent on the team's overall perception of its capability. Individuals were peer‐rated on the extent to which they displayed interpersonal and performance management teamwork behaviors over the course of an 8 week business simulation. The personality trait of agreeableness predicted interpersonal teamwork behavior, while the personality traits of conscientiousness and core self‐evaluation (CSE) predicted performance management behavior. Multilevel analysis showed that collective efficacy influenced the extent to which an individual engaged in both types of behavior, and was also a cross‐level moderator of the relationship between agreeableness and interpersonal behavior and the relationship between CSE and performance management behavior. At the team level, interpersonal behavior mediated between collective efficacy and team performance. The study's results show that in team settings the personality and individual behavior relationship may depend on group level confidence perceptions. Copyright © 2010 John Wiley & Sons, Ltd.
Applications of HILIC for targeted and non‐targeted LC/MS analyses in drug discovery
Authors: Onorato Joelle M. , Langish Robert , Bellamine Aouatef , Shipkova Petia 
Published: February 2010

AbstractRP‐HPLC has largely been the analytical method of choice in the pharmaceutical industry for many years because of the poor aqueous solubility and hydrophobicity of most small molecule drug candidates. RP‐HPLC coupled to MS has provided an excellent analytical tool for qualitatively and quantitatively determining levels of drug molecules or drug metabolites for studies such as purity assessment and pharmacokinetic profiling. Quantitation of endogenous metabolites is an emerging field in drug discovery, gaining popularity for evaluating pharmacokinetic–pharmacodynamic relationships and targeting activity and efficacy. While RP‐HPLC‐MS is suitable for a range of applications, many endogenous molecules, especially those found in urine, are small polar compounds that do not retain well by RP‐HPLC. This has made hydrophilic interaction LC (HILIC) an attractive alternative and useful approach to polar molecule analysis. Additionally, because HILIC is routinely used with traditional RP organic solvents such as ACN and methanol, it can be easily coupled to MS. This paper will review selected examples from the current literature as well as discuss some new applications from the author's own laboratory focusing on the applicability of HILIC to quantitative and qualitative profiling of endogenous metabolites in drug discovery.
Off‐line comprehensive two‐dimensional hydrophilic interaction×reversed phase liquid chromatographic analysis of green tea phenolics
Authors: Kalili Kathithileni M. , de Villiers André 
Published: February 2010

AbstractThe separation of green tea phenolic compounds by comprehensive 2‐D LC (LC×LC) has been studied. An off‐line LC×LC system was designed based on hydrophilic interaction chromatography in the first dimension and gradient RP‐LC using a C18 column in the second dimension, to separate compounds based on polarity and hydrophobicity, respectively. Green tea was found to contain a complex composition of low molecular weight phenolic compounds, identified by fluorescence, diode‐array and negative ESI‐MS detection systems. The LC×LC system was characterized by a very high practical peak capacity (>2100, in ∼22.5 h) due to the low degree of correlation (r2<0.2) between the selected separation mechanisms. The proposed methodology demonstrated its suitability for the analysis of various groups of phenolic compounds including proanthocyanidins, phenolic acids, flavonols and flavonol derivatives, all of which cannot be separated in a single analysis by conventional 1‐D HPLC methods.
Evaluation of thrust force generated for a robotic fish propelled with polypyrrole actuators
Authors: McGovern Scott T , Abbot Marc , Emery Richard , Alici Gursel , Truong Van‐Tan , Spinks Geoffrey M , Wallace Gordon G 
Published: February 2010

AbstractSwimming‐type robotic fish are being developed as mobile sensor platforms that have the potential to outperform existing underwater vehicles in terms of manoeuvrability, miniaturisation and silent operation. Conducting polymer actuators are potential candidates for propelling a flapping tail fin for a robotic fish. This study introduces a method for directly measuring the thrust force generated by a polypyrrole (PPy) powered tail fin. The effects of voltage stimulus (waveform shape and frequency) and tail fin shape on the thrust force were determined. A square wave voltage input was shown to generate the highest thrust forces as fast bending actuation was induced. The thrust force tended to decrease at higher operating frequencies as a result of the reduced actuation occurring in the PPy layers. Increases in the tail fin area tended to lower the frequency where the peak in thrust force was achieved. Tail fin shape was also shown to be important to the force‐frequency behaviour. When attached to an untethered robotic fish, the swimming speed tended to increase with increasing voltage input frequency. There was also an optimum frequency that enabled the fastest acceleration from rest that happened to be higher than the frequency that gave the peak thrust force. This was presumed to be due to the complicated swimming behaviour involving the side‐to‐side movement of the fish nose at low flap frequencies. The study provides valuable insight into the means for tailoring polymer actuator performance to achieve maximum fish swimming speeds. Copyright © 2010 Society of Chemical Industry
A convenient microwave‐enhanced solid‐phase synthesis of short chain N‐methyl‐rich peptides
Authors: Rodríguez Hortensia , Suarez Margarita , Albericio Fernando 
Published: February 2010

AbstractStructural modification of the peptide backbone via N‐methylation is a powerful tool to modulate the pharmacokinetic profile and biological activity of peptides. Here we describe a rapid and highly efficient microwave(MW)‐assisted Fmoc/tBu solid‐phase method to prepare short chain N‐methyl‐rich peptides, using Rink amide p‐methylbenzhydrylamine (MBHA) resin as solid‐phase support. This method produces peptides in high yield and purity, and reduces the time required for Fmoc‐N‐methyl amino acid coupling. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Controlling the helical screw sense of peptides with C‐terminal L‐valine
Authors: Demizu Yosuke , Yamagata Nanako , Sato Yukiko , Doi Mitsunobu , Tanaka Masakazu , Okuda Haruhiro , Kurihara Masaaki 
Published: February 2010

AbstractOne chiral L‐valine (L‐Val) was inserted into the C‐terminal position of achiral peptide segments constructed from α‐aminoisobutyric acid (Aib) and α,β‐dehydrophenylalanine (ΔZPhe) residues. The IR, 1H NMR and CD spectra indicated that the dominant conformations of the pentapeptide Boc‐Aib‐ΔPhe‐(Aib)2‐L‐Val‐NH‐Bn (3) and the hexapeptide Boc‐Aib‐ΔPhe‐(Aib)3‐L‐Val‐NH‐Bn (4) in solution were both right‐handed (P) 310‐helical structures. X‐ray crystallographic analyses of 3 and 4 revealed that only a right‐handed (P) 310‐helical structure was present in their crystalline states. The conformation of 4 was also studied by molecular‐mechanics calculations. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Identification of small peptides mimicking the R2 C‐terminus of Mycobacterium tuberculosis ribonucleotide reductase
Authors: Ericsson Daniel J. , Nurbo Johanna , Muthas Daniel , Hertzberg Kalle , Lindeberg Gunnar , Karlén Anders , Unge Torsten 
Published: February 2010

AbstractRibonucleotide reductase (RNR) is a viable target for new drugs against the causative agent of tuberculosis, Mycobacterium tuberculosis. Previous work has shown that an N‐acetylated heptapeptide based on the C‐terminal sequence of the smaller RNR subunit can disrupt the formation of the holoenzyme sufficiently to inhibit its function. Here the synthesis and binding affinity, evaluated by competitive fluorescence polarization, of several truncated and N‐protected peptides are described. The protected single‐amino acid Fmoc‐Trp shows binding affinity comparable to the N‐acetylated heptapeptide, making it an attractive candidate for further development of non‐peptidic RNR inhibitors. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.
Beneficial effects of quercetin on sperm parameters in streptozotocin‐induced diabetic male rats
Authors: Khaki Arash , Fathiazad Fatemeh , Nouri Mohammad , Khaki AmirAfshin , Maleki Navid A. , Khamnei Hossein Jabbari , Ahmadi Porya 
Published: February 2010

AbstractQuercetin (QR) is a strong antioxidant and has been shown to reduce oxidative stress in the long‐term treatment of streptozotocin (STZ)‐induced diabetes in animal models. Antioxidants have significant effects on spermatogenesis, sperm biology and oxidative stress, and changes in antioxidant capacity are considered to be involved in the pathogenesis of chronic diabetes mellitus. The present study aims to examine the influence of QR on spermatogenesis in STZ‐induced diabetes in male Wistar rats. Animals (n = 50) were allocated into five groups: Group 1: Control rats given 0.5 ml of 20% glycerol in 0.9% normal saline. Group 2: Control rats given buffer (pH4.0).Group 3: diabetic controls. Group 4: rats given QR 15 mg/kg/day (i.p.). Group 5: STZ + QR rats. Animals were kept in standard conditions. At the end of the experiment (28th day), blood samples were taken for determination of testosterone, total antioxidant capacity, and levels of malondialdehyde and oxidized low‐density lipoprotein. All rats were euthanized, testes were dissected out and spermatozoa were collected from the epididymis for analysis. Sperm numbers, percentages of sperm viability and motility, and total serum testosterone increased significantly in QR‐treated diabetic rats (P < 0.05) compared with control groups. In histopathology, degeneration and inflammation in testes cells associated with diabetes were improved and testes weights in the QR‐treated diabetic group decreased significantly in comparison with controls (P < 0.05). We conclude that QR has significant beneficial effects on the sperm viability, motility, and serum total testosterone and could be effective for maintaining healthy sperm parameters and male reproductive function in diabetic rats. Copyright © 2010 John Wiley & Sons, Ltd.
Substituent effects on SN2 reaction between substituted benzyl chloride and chloride ion in gas phase
Authors: Ebrahimi A. , Habibi‐Khorassani S. M. , Doosti M. 
Published: February 2010

AbstractNucleophilic substitution reaction between some substituted benzyl chlorides and chloride ion has been investigated by ab initio and DFT methods. New calculated energy data are in better agreement with experimental data. The electron‐withdrawing groups increase the energy barriers and the electron‐donating groups decrease them. The changes of geometrical parameters and energy data are in good agreement with the results of atoms in molecules and natural bond orbital analyses. The relationship between Hammett coefficients and energy data (and geometry parameters) has been established and the ρ constant has been calculated for this reaction. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Configuration interaction calculations on the 2P ground state of boron atom and C+ using Slater orbitals
Authors: Ruiz M. Belén , Rojas Miguel , Chicón Guillermo , Otto Peter 
Published: February 2010

AbstractConfiguration Interaction (CI) calculations on the ground 2P state of boron atom are presented using a wave function expansion constructed with L‐S eigenfunction configurations of s‐, p‐, and d‐Slater orbitals. Two procedures of optimization of the orbital exponents have been investigated. First, CI(SD) calculations including few types of configurations and full optimization of the orbital exponents led to the energy −24.63704575 a.u. Second, full‐CI (FCI) calculations including a large number of configuration types using a fixed set of orbital exponents for all configurations gave −24.63405222 a.u. using the basis [4s3p2d] and 2157 configurations, and to an improved result of −24.64013999 a.u. for 3957 configurations and a [5s4p3d] basis. This last result is better than earlier calculations of Schaefer and Harris (Phys Rev 1968, 167, 67), and compares well with the recent ones from Froese Fischer and Bunge (personal communication). In addition, using the same wave functions, CI calculations of the boron isoelectronic ion C+ have been performed obtaining an energy of −37.41027598 a.u. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011