bluuebunny/crossref_metadata_2025_split huggingface dataset:
Depth‐sensitive Raman spectroscopy combined with optical coherence tomography for layered tissue analysis
Authors: Khan Khan M. , Krishna Hemant , Majumder Shovan K. , Rao K. Divakar , Gupta Pradeep K. 
Published: January 2013

AbstractComplete characterization of a layered tissue requires probing both the biochemical and the morphological information from its different layers at various depths. We report the development of a combined Raman spectroscopy (RS) and optical coherence tomography (OCT) system that is capable of measuring depth‐sensitive Raman signal from the tissue layers imaged by the OCT. The sample arm of a real‐time time‐domain OCT system was modified to allow for co‐alignment of the OCT with the Raman probe beam. The depth sensitivity of Raman was obtained by incorporating confocal Raman configuration that minimized out‐of‐focus Raman scattered light. The system was first validated using a layered phantom prepared by depositing a thin layer of paraffin over acetaminophen. A good correlation was observed between the OCT images and the Raman signal. The system was also used to record OCT and Raman images of a resected mucosal tissue sample. While OCT image showed the presence of epithelial and stromal layers, Raman spectra measured from these layers confirmed the biochemical difference between the two. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonadhesive, silica nanoparticles‐based brush‐coated contact lens cases—Compromising between ease of cleaning and microbial transmission to contact lenses
Authors: Qu Wenwen , Hooymans Johanna M. M. , Qiu Jun , de‐Bont Nik , Gelling Onko‐Jan , van der Mei Henny C. , Busscher Henk J. 
Published: January 2013

AbstractSurface properties of lens cases are determinant for their cleanability and for microbial transmission from lens cases to contact lenses (CLs). PEG‐polymer‐brush‐coatings are known to decrease microbial adhesion more than other surface‐coatings. Here, we applied a robust, silica nanoparticles‐based brush‐coating to polypropylene cases to evaluate their ease of cleaning and probability of bacterial transmission to CLs. Adhesion forces of nine bacterial strains (Pseudomonas, Staphylococci, and Serratia) to rigid CLs, polypropylene, and silica nanoparticles‐based brush‐coated polypropylene were measured using atomic‐force‐microscopy and subjected to Weibull analyses to yield bacterial transmission probabilities. Biofilms of each strain were grown in coated and uncoated cases and rinsed with a NaCl or antimicrobial lens care solution. Residual, viable organisms were quantified. Bacterial adhesion forces of all strains were significantly, up to tenfold smaller on brush‐coated than on uncoated polypropylene. This yielded, higher transmission probabilities to a CL, but mild‐rinsing yielded 10–100 fold higher removal of bacteria from brush‐coated than from polypropylene cases. Moreover, due to weak adhesion forces, bacteria on brush‐coated cases were two‐to‐three fold more susceptible to an antimicrobial lens care solution than on polypropylene cases. Therewith, the design of lens case surfaces is a compromise between ease of cleaning and transmission probability to CLs. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
PLGA/PEG‐hydrogel composite scaffolds with controllable mechanical properties
Authors: Rahman Cheryl V. , Kuhn Gisela , White Lisa J. , Kirby Giles T. S. , Varghese Oommen P. , McLaren Jane S. , Cox Helen C. , Rose Felicity R. A. J. , Müller Ralph , Hilborn Jöns , Shakesheff Kevin M. 
Published: January 2013

AbstractBiodegradable polymer scaffolds have great potential for regenerative medicine applications such as the repair of musculoskeletal tissues. Here, we describe the development of scaffolds that blend hydrogel components with thermoplastic materials, combining the unique properties of both components to create mouldable formulations. This study focuses on the structural and mechanical properties of the composite scaffolds, produced by combining temperature‐sensitive poly(DL‐lactic acid‐co‐glycolic acid) (PLGA)/poly(ethylene glycol) (PEG) particles with a hydrogel component [Pluronic F127, fibrin or hyaluronic acid (HyA)]. The composite formulations solidified over time at 37°C, with a significant increase (p ≤ 0.05) in compressive strength observed from 15 min to 2 h at this temperature. The maximum compressive strength was 1.2 MPa for PLGA/PEG‐Pluronic F127 scaffolds, 2.4 MPa for PLGA/PEG‐HyA scaffolds and 0.6 MPa for PLGA/PEG‐fibrin scaffolds. Porosity for each of the PLGA/PEG‐hydrogel formulations tested was between 50 and 51%. This study illustrates the ability to combine this thermoplastic PLGA/PEG system with hydrogels to fabricate composite scaffolds, and demonstrates that altering the particle to hydrogel ratio produces scaffolds with varying mechanical properties. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Comparison of bare metal and statin‐coated coils on rates of intra‐aneurysmal tissue organization in a rat model of aneurysm
Authors: Kodama Tomonobu , Iwata Hiroo 
Published: January 2013

AbstractEndovascular treatment of intracranial aneurysms with detachable coils has been accepted widely. Problems of coil compaction, recanalization and rare endothelialization at the aneurysm orifice are not yet solved. We investigated the efficacy of a simvastatin coating applied without any additional matrix to coils to accelerate thrombus organization in the cavity in a rat model of aneurysm. Twelve metal coils coated with simvastatin and 12 bare coils were inserted into the ligated external carotid arterial (ECA) sacs of rats. The ECA sacs were removed 2 or 4 weeks after the coils were implanted and examined by histology and immunohistochemical assay. The organized areas in the ECA sacs in the simvastatin group (73.6 ± 19.4%, 2 wk; 83.4 ± 11.1%, 4 wk) was significantly higher p = 0.003, 2 wk; p = 0.0004, 4 wk than the bare metal group at 2 and 4 weeks (20.5 ± 10.7%, 2 wk, p < 0.003; 37.4 ± 20.6%, 4 wk, p < 0.0004). Organized tissues that formed around the coils coated with simvastatin were characterized by an accumulation of cells positive for αSMA and collagen connective matrix. Tissues also were accompanied by marked formation of endothelium at the orifice of the ECA sac. We suggest that coating coils with simvastatin effectively accelerated organization within the aneurysms and endothelialization over the coil. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part 2013.
Comparison of ceramic‐on‐metal and metal‐on‐metal hip prostheses under adverse conditions
Authors: Williams Sophie , Al‐Hajjar Mazen , Isaac Graham H. , Fisher John 
Published: January 2013

AbstractCeramic‐on‐metal (COM) hip replacements, where the head is BIOLOX® Delta ceramic and the liner is CoCrMo alloy, have demonstrated reduced wear under standard simulator conditions compared to metal‐on‐metal (MOM) bearings. COM hips are now being used clinically around the world. MOM hip resurfacings have raised concerns regarding poor clinical performance and increased in vivo wear was associated with steeply inclined acetabular components and translationally malpositioned components. The aim of this study was to compare the wear rates of MOM and COM total hip prostheses under adverse edge‐loading conditions in a hip simulator test. COM and MOM 36 mm hip prostheses were tested in a hip simulator, with liners mounted to provide a clinical inclination angle of 55°. A simplified gait cycle and microseparation conditions were applied for two million cycles in 25% new born calf serum. The overall mean volumetric wear rate of COM bearings under adverse conditions was 0.36 ± 0.55 mm3/million cycles; this was significantly less than MOM wear (1.32 ± 0.91 mm3/million cycles). Under these adverse conditions; the contact zone on the head intersects the rim of the cup causing substantially elevated contact stresses, disrupting the protective boundary and mixed lubrication regime causing changes in types and severity of wear mechanisms. In COM bearings, the harder head does not become damaged when there is lubricant starvation and wear does not accelerate. In conclusion, COM bearings showed reduced wear compared to MOM bearings under standard and adverse clinically relevant simulator conditions and COM bearings may provide an advantage over MOM bearings under edge‐loading conditions clinically. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Characterization of porous polymethylmethacrylate space maintainers for craniofacial reconstruction
Authors: Wang Limin , Yoon Diana M. , Spicer Patrick P. , Henslee Allan M. , Scott David W. , Wong Mark E. , Kasper F. Kurtis , Mikos Antonios G. 
Published: January 2013

AbstractPorous polymethylmethacrylate (PMMA) has been used as an alloplastic bone substitute in the craniofacial complex, showing integration with the surrounding soft and hard tissue. This study investigated the physicochemical properties of curing and cured mixtures of a PMMA‐based bone cement and a carboxymethylcellulose (CMC) gel porogen. Four formulations yielding porous PMMA of varied porosity were examined; specifically, two groups containing 30% (w/w) CMC gel in the mixture using a 7% (w/v) or 9% (w/v) stock CMC gel (30‐7 and 30‐9, respectively) and two groups containing 40% (w/w) CMC gel (40‐7 and 40‐9). An additional group comprising solid PMMA without CMC was investigated. The incorporation of the CMC gel into the PMMA bone cement during polymerization decreased the setting time from 608 ± 12 s for the solid PMMA to 427 ± 10 s for the 40‐9 group, and decreased the maximum temperature from 81 ± 4°C for the solid PMMA to 38 ± 2°C for the 40‐9 group. The porous PMMA groups exhibited reduced compressive strength and bending modulus and strength relative to the solid PMMA. All the porous PMMA formulations released more unconverted methylmethacrylate (MMA) monomer and N,N‐dimethyl‐p‐toluidine (DMT) from cured specimens and less MMA and DMT from curing specimens than the solid PMMA. The data suggest that the physicochemical properties of the porous PMMA formulations are appropriate for their application in craniofacial space maintenance. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
The effect of PCL‐TCP scaffold loaded with mesenchymal stem cells on vertical bone augmentation in dog mandible: A preliminary report
Authors: Khojasteh Arash , Behnia Hossein , Hosseini Fatemeh Sadat , Dehghan Mohammad Mehdi , Abbasnia Pegah , Abbas Fatemeh Mashhadi 
Published: January 2013

AbstractPolycaprolactone‐tricalcium phosphate (PCL‐TCP), a new composite scaffold, has been shown to facilitate early revascularization and speed up bone regeneration process. The objective of this study was to evaluate the effect of PCL‐TCP seeded with mesenchymal stem cells (MSCs) on healing of the vertical bone critical sized defect in dog's mandible. Bone marrow aspirate from dog humerous was cultured and the stemness of the cells was examined by differentiation staining methods and flow cytometric analysis. Third passage subculture cells (5 × 105 cells) were loaded on 20 × 10 × 10 mm3 and incubated for 48 h. The presence of MSCs in the pores was evaluated by scanning electron microscope. Bilateral mandibular premolar teeth were extracted in four dogs and the buccal and lingual bone plates were reduced to make a vertical defect. Cell‐loaded scaffolds were fixed in right side and left side received pure PCL‐TCP scaffolds as a control side defects. Histomorphometric analysis after 8 weeks of the scaffold implantation showed higher amount of lamellar bone in the test side (48.63%) than control side (17.27%) (p < 0.05).The results suggest that PCL‐TCP may be an appropriate scaffold for loading MSCs in bone regeneration. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
HIV infection is strongly associated with hip fracture risk, independently of age, gender, and comorbidities: A population-based cohort study
Authors: Güerri-Fernandez Robert , Vestergaard Peter , Carbonell Cristina , Knobel Hernando , Avilés Francesc Fina , Castro Alberto Soria , Nogués Xavier , Prieto-Alhambra Daniel , Diez-Perez Adolfo 
Published: January 2013

ABSTRACT

HIV infection and antiretroviral therapies have detrimental effects on bone metabolism, but data on their impact on fracture risk are controversial. We conducted a population-based cohort study to explore the association between clinical diagnosis of HIV infection and hip and major osteoporotic fracture risk. Data were obtained from the SIDIAPQ database, which contains clinical information for &gt;2 million patients in Catalonia, Spain (30% of the population). We screened the database to identify participants with a clinical diagnosis of HIV infection, and ascertained incident hip and osteoporotic major fractures in the population aged 40 years or older in 2007 to 2009. In addition, data on incident fractures involving hospital admission were obtained from the Hospital Admissions database. Cox regression models were used to estimate hazard ratios (HRs) for the HIV-infected versus uninfected participants. Models were adjusted for age, sex, body mass index, smoking status, alcohol drinking, oral glucocorticoid use, and comorbid conditions (Charlson index). Among 1,118,156 eligible participants, we identified 2489 (0.22%) subjects with a diagnosis of HIV/AIDS. Age- and sex-adjusted HR for HIV/AIDS were 6.2 (95% confidence interval [CI] 3.5–10.9; p &lt; 0.001) and 2.7 (2.01–3.5; p &lt; 0.001) for hip and major fractures, respectively; this remained significant after adjustment for all mentioned potential confounders: HR 4.7 (2.4–9.5; p &lt; 0.001) and 1.8 (1.2–2.5; p = 0.002). After stratifying by age, the association between HIV infection and major fractures was attenuated for those aged &lt;59 years (adjusted HR 1.35 [0.88–2.07], p = 0.17) but appeared stronger in older patients (adjusted HR 2.11 [1.05–4.22], p = 0.035). We report a strong association between HIV infection and hip fracture incidence, with an almost fivefold increased risk in the HIV infected, independent of sex, age, smoking, alcohol drinking, and comorbidities. Similarly, we demonstrate a 75% higher risk of all clinical fractures and a 60% increase in risk of non-hip clinical fractures among patients with a diagnosis of HIV infection.
Pyk2 regulates megakaryocyte-induced increases in osteoblast number and bone formation
Authors: Cheng Ying-Hua , Hooker R Adam , Nguyen Khanh , Gerard-O'Riley Rita , Waning David L , Chitteti Brahmananda R , Meijome Tomas E , Chua Hui Lin , Plett Artur P , Orschell Christie M , Srour Edward F , Mayo Lindsey D , Pavalko Fredrick M , Bruzzaniti Angela , Kacena Melissa A 
Published: January 2013

ABSTRACT

Preclinical and clinical evidence from megakaryocyte (MK)-related diseases suggests that MKs play a significant role in maintaining bone homeostasis. Findings from our laboratories reveal that MKs significantly increase osteoblast (OB) number through direct MK-OB contact and the activation of integrins. We, therefore, examined the role of Pyk2, a tyrosine kinase known to be regulated downstream of integrins, in the MK-mediated enhancement of OBs. When OBs were co-cultured with MKs, total Pyk2 levels in OBs were significantly enhanced primarily because of increased Pyk2 gene transcription. Additionally, p53 and Mdm2 were both decreased in OBs upon MK stimulation, which would be permissive of cell cycle entry. We then demonstrated that OB number was markedly reduced when Pyk2−/− OBs, as opposed to wild-type (WT) OBs, were co-cultured with MKs. We also determined that MKs inhibit OB differentiation in the presence and absence of Pyk2 expression. Finally, given that MK-replete spleen cells from GATA-1–deficient mice can robustly stimulate OB proliferation and bone formation in WT mice, we adoptively transferred spleen cells from these mice into Pyk2−/− recipient mice. Importantly, GATA-1–deficient spleen cells failed to stimulate an increase in bone formation in Pyk2−/− mice, suggesting in vivo the important role of Pyk2 in the MK-induced increase in bone volume. Further understanding of the signaling pathways involved in the MK-mediated enhancement of OB number and bone formation will facilitate the development of novel anabolic therapies to treat bone loss diseases.
Tumor localization and biochemical response to cure in tumor-induced osteomalacia
Authors: Chong William H , Andreopoulou Panagiota , Chen Clara C , Reynolds James , Guthrie Lori , Kelly Marilyn , Gafni Rachel I , Bhattacharyya Nisan , Boyce Alison M , El-Maouche Diala , Crespo Diana Ovejero , Sherry Richard , Chang Richard , Wodajo Felasfa M , Kletter Gad B , Dwyer Andrew , Collins Michael T 
Published: January 2013

ABSTRACT

Tumor-induced osteomalacia (TIO) is a rare disorder of phosphate wasting due to fibroblast growth factor-23 (FGF23)-secreting tumors that are often difficult to locate. We present a systematic approach to tumor localization and postoperative biochemical changes in 31 subjects with TIO. All had failed either initial localization, or relocalization (in case of recurrence or metastases) at outside institutions. Functional imaging with 111Indium-octreotide with single photon emission computed tomography (octreo-SPECT or SPECT/CT), and 18fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT) were performed, followed by anatomic imaging (CT, MRI). Selective venous sampling (VS) was performed when multiple suspicious lesions were identified or high surgical risk was a concern. Tumors were localized in 20 of 31 subjects (64.5%). Nineteen of 20 subjects underwent octreo-SPECT imaging, and 16 of 20 FDG-PET/CT imaging. Eighteen of 19 (95%) were positive on octreo-SPECT, and 14 of 16 (88%) on FDG-PET/CT. Twelve of 20 subjects underwent VS; 10 of 12 (83%) were positive. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were as follows: sensitivity = 0.95, specificity = 0.64, PPV = 0.82, and NPV = 0.88 for octreo-SPECT; sensitivity = 0.88, specificity = 0.36, PPV = 0.62, and NPV = 0.50 for FDG-PET/CT. Fifteen subjects had their tumor resected at our institution, and were disease-free at last follow-up. Serum phosphorus returned to normal in all subjects within 1 to 5 days. In 10 subjects who were followed for at least 7 days postoperatively, intact FGF23 (iFGF23) decreased to near undetectable within hours and returned to the normal range within 5 days. C-terminal FGF23 (cFGF23) decreased immediately but remained elevated, yielding a markedly elevated cFGF23/iFGF23 ratio. Serum 1,25-dihydroxyvitamin D3 (1,25D) rose and exceeded the normal range. In this systematic approach to tumor localization in TIO, octreo-SPECT was more sensitive and specific, but in many cases FDG-PET/CT was complementary. VS can discriminate between multiple suspicious lesions and increase certainty prior to surgery. Sustained elevations in cFGF23 and 1,25D were observed, suggesting novel regulation of FGF23 processing and 1,25D generation.
Vitamin D activation of functionally distinct regulatory miRNAs in primary human osteoblasts
Authors: Lisse Thomas S , Chun Rene F , Rieger Sandra , Adams John S , Hewison Martin 
Published: January 2013

ABSTRACT

When bound to the vitamin D receptor (VDR), the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25D) is a potent regulator of osteoblast transcription. Less clear is the impact of 1,25D on posttranscriptional events in osteoblasts, such as the generation and action of microRNAs (miRNAs). Microarray analysis using replicate (n = 3) primary cultures of human osteoblasts (HOBs) identified human miRNAs that were differentially regulated by &gt;1.5-fold following treatment with 1,25D (10 nM, 6 hours), which included miRNAs 637 and 1228. Quantitative reverse transcription PCR analyses showed that the host gene for miR-1228, low-density lipoprotein receptor-related protein 1 (LRP1), was coinduced with miR-1228 in a dose-dependent fashion following treatment with 1,25D (0.1–10 nM, 6 hours). By contrast, the endogenous host gene for miR-637, death-associated protein kinase 3 (DAPK3), was transcriptionally repressed by following treatment with 1,25D. Analysis of two potential targets for miR-637 and miR-1228 in HOB, type IV collagen (COL4A1) and bone morphogenic protein 2 kinase (BMP2K), respectively, showed that 1,25D-mediates suppression of these targets via distinct mechanisms. In the case of miR-637, suppression of COL4A1 appears to occur via decreased levels of COL4A1 mRNA. By contrast, suppression of BMP2K by miR-1228 appears to occur by inhibition of protein translation. In mature HOBs, small interfering RNA (siRNA) inactivation of miR-1228 alone was sufficient to abrogate 1,25D-mediated downregulation of BMP2K protein expression. This was associated with suppression of prodifferentiation responses to 1,25D in HOB, as represented by parallel decrease in osteocalcin and alkaline phosphatase expression. These data show for the first time that the effects of 1,25D on human bone cells are not restricted to classical VDR-mediated transcriptional responses but also involve miRNA-directed posttranscriptional mechanisms.
A physically based diode model for circuit simulation
Authors: Khachroumi Sofiane , Amouri Aymen , Ben Salah Tarek , Morel Hervé 
Published: January 2013

SUMMARYA physically based power PiN diode model is presented. Eigen value internal approximation method is used to solve the ambipolar diffusion equation. This model is implemented in SIMPLORER circuit simulator using VHDL‐AMS language. The proposed model can be used in both circuit simulators and the optimization of a given power PiN diode. Good agreement is obtained by comparing the results of the suggested model with experimental data. Copyright © 2013 John Wiley & Sons, Ltd.
A record of Lateglacial/Holocene environmental change from a high‐elevation site in the Intermountain West, USA
Authors: Brunelle Andrea , Minckley Thomas A. , Lips Elliott , Burnett Paul 
Published: January 2013

AbstractRecords of past vegetation and fire history can be complicated by changes in the depositional environment of a sampling location. However, these changes can alternatively be used as a measure of climate variability. Our study site, ca. 18.0 cal. ka BP record from Little Brooklyn Lake, Wyoming, located near the crest of the Snowy Range, records three moisture states. Initially, the lake was likely a glacier‐fed pond indicated by the presence of Pediastrum algae colonies. Around 13.0 cal. ka BP this pond transitioned to a meadow environment, suggested by the loss of Pediastrum algae colonies and slow sedimentation rates. Meadow conditions were maintained until ca. 5.0 cal. ka BP when Pediastrum algae colony abundance increased,indicating the formation of a shallow lake. From 18.0 to ca. 5.0 cal. ka BP, the pollen record is suggestive of alpine vegetation conditions with relatively high spruce and herbaceous taxa. Low charcoal influx also characterizes the period between 18.0 and 5.0 cal. ka BP. After 5.0 cal. ka BP, the coincidence of the formation of shallow lake and pollen data, indicating a shift to a spruce and fir forest, suggests an increase in effective moisture. Fire remained rare in this basin over the entire record, however, once the lake established sedimentation rates and charcoal influx increased. Copyright © 2013 John Wiley & Sons, Ltd.