bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficient transfer of human adipose‐derived stem cells by chitosan/gelatin blend films
Authors: Cheng Nai‐Chen , Chang Hsu‐Hsien , Tu Yuan‐Kun , Young Tai‐Horng 
Published: May 2012

AbstractAdipose‐derived stem cells (ASCs) are a potential source of abundant mesenchymal stem cells and represent a promising cell‐based therapy for tissue damage or degeneration conditions. Previous investigations have demonstrated enhanced therapeutic effects of ASCs in a three‐dimensional spheroid culture formulation. In this study, we hypothesize that a composite membrane made of chitosan/gelatin (C/G) is beneficial to facilitate transfer of human ASCs in spheroids. Increasing chitosan content within the blends enhanced the mechanical properties of the sample, including tensile strength and elongation‐at‐break ratio. Although ASC spheroids developed shortly after seeding on pure chitosan films, increasing gelatin proportion in the C/G blends promoted cell adhesion onto the membranes. We also found that ASCs did not proliferate on chitosan films, but C/G blends of different ratios supported ASC proliferation in the first 4 days of culture. However, ASCs on all C/G blends started to detach from the films to form spheroids after day 4, while ASCs on pure gelatin films remained attached and continued to grow. Gradual gelatin release from the C/G blend films, leading to enriched chitosan content in the blends, probably encouraged ASC detachment and spheroid formation. We placed porous collagen matrix on ASC‐seeded C/G blends to simulate the application of ASC‐seeded C/G films onto injured tissue and found that a C/G film composed of 75% chitosan could facilitate significantly more cell transfer into the overlying collagen sponge. Therefore, a blend film containing 75% chitosan and 25% gelatin showed promising results to serve as a biomaterial for human ASC‐based cell therapy. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B:, 2012.
Effect of amorphous calcium phosphate and silver nanocomposites on dental plaque microcosm biofilms
Authors: Cheng Lei , Weir Michael D. , Xu Hockin H. K. , Antonucci Joseph M. , Lin Nancy J. , Lin‐Gibson Sheng , Xu Sarah M. , Zhou Xuedong 
Published: May 2012

AbstractA dental composite containing amorphous calcium phosphate nanoparticles (NACP) was developed that released calcium (Ca) and phosphate (PO4) ions and possessed acid‐neutralization capability. There has been little study on incorporation of antibacterial agents into calcium phosphate composites. The objective of this study was to investigate the effect of silver nanoparticle (NAg) mass fraction in NACP nanocomposite on mechanical properties and dental plaque microcosm biofilm for the first time. NACP nanoparticles of 116 nm were synthesized via a spray‐drying technique. NAg nanoparticles were synthesized using Ag 2‐ethylhexanoate and 2‐(tert‐butylamino)ethyl methacrylate, yielding NAg of particle size of 2.7 nm that were well‐dispersed in the resin. Five NACP nanocomposites were fabricated with NAg mass fractions of 0, 0.028, 0.042, 0.088, and 0.175%, respectively. Mechanical properties of NACP nanocomposites containing 0–0.042% of NAg matched those of a commercial composite without antibacterial activity. Live/dead assay of dental plaque microcosm biofilms showed complete coverage with live bacteria on commercial composite. However, there were increasingly more dead bacteria with higher NAg content in the NACP nanocomposite. Colony‐forming unit (CFU) counts for total microorganisms, total streptococci, and mutans streptococci for NACP nanocomposite with 0.042% NAg were about 1/4 those of commercial composite. Lactic acid production on NACP nanocomposite with 0.042% NAg was 1/3 that on commercial composite. In conclusion, novel NACP–NAg nanocomposites were developed which possessed good mechanical properties and potent antibacterial properties, with substantially reduced biofilm viability and lactic acid production. Hence, the NACP–NAg nanocomposites are promising for dental restorations with remineralizing and antibacterial capabilities. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 00B:000–000, 2012
Development of biodegradable polyurethane and bioactive glass nanoparticles scaffolds for bone tissue engineering applications
Authors: de Oliveira Agda Aline Rocha , de Carvalho Sandhra Maria , de Fátima Leite Maria , Oréfice Rodrigo Lambert , de Magalhães Pereira Marivalda 
Published: May 2012

AbstractThe development of polymer/bioactive glass has been recognized as a strategy to improve the mechanical behavior of bioactive glass‐based materials. Several studies have reported systems based on bioactive glass/biopolymer composites. In this study, we developed a composite system based on bioactive glass nanoparticles (BGNP), obtained by a modified Stöber method. We also developed a new chemical route to obtain aqueous dispersive biodegradable polyurethane. The production of polyurethane/BGNP scaffolds intending to combine biocompatibility, mechanical, and physical properties in a material designed for tissue engineering applications. The composites obtained were characterized by structural, biological, and mechanical tests. The films presented 350% of deformation and the foams presented pore structure and mechanical properties adequate to support cell growth and proliferation. The materials presented good cell viability and hydroxyapatite layer formation upon immersion in simulated body fluid. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
Surface chemistry of bulk nanocrystalline pure iron and electrochemistry study in gas‐flow physiological saline
Authors: Nie F. L. , Zheng Y. F. 
Published: May 2012

AbstractConventional microcrystalline pure iron (MC‐Fe) becomes a new candidate as biodegradable metals, which has the insufficient physical feature and inferior biodegradation behavior. Novel bulk nanocrystalline pure iron (NC‐Fe) was fabricated via equal channel angular pressing technique in the present work to overcome these problems. The contact angle test with water and glycerol droplets shows a smaller angle (though >90°) of NC‐Fe than that of MC‐Fe, which implies a lower surface energy of NC‐Fe. The surface roughness of NC‐Fe increased greatly than that of MC‐Fe. A further comparative study of corrosion and electrochemistry performance between NC‐Fe and its original MC‐Fe was investigated in physiological saline with different dissolved oxygen concentration, aiming to in vitro simulate the corrosion process of coronary stent occurred in physiological environment. The electrochemical impedance spectra analysis and anodic polarization measurements indicated that the NC‐Fe exhibited higher corrosion resistance than that of the MC‐Fe; meanwhile obvious enhanced corrosion resistance with the decrement of dissolved oxygen concentration was observed. Related equivalent circuit model and surface reconstruction process were further discussed, and the degradation mechanism of the MC‐Fe and NC‐Fe were finally established. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.
The dynamics of PKC‐induced phosphorylation triggered by Ca2+ oscillations in mouse eggs
Authors: Gonzalez‐Garcia Jose Raul , Machaty Zoltan , Lai F. Anthony , Swann Karl 
Published: May 2012

AbstractFertilization of mammalian eggs is characterized by a series of Ca2+ oscillations triggered by a phospholipase C activity. These Ca2+ increases and the parallel generation of diacylglycerol (DAG) stimulate protein kinase C (PKC). However, the dynamics of PKC activity have not been directly measured in living eggs. Here, we have monitored the dynamics of PKC‐induced phosphorylation in mouse eggs, alongside Ca2+ oscillations, using fluorescent C‐kinase activity reporter (CKAR) probes. Ca2+ oscillations triggered either by sperm, phospholipase C zeta (PLCζ) or Sr2+ all caused repetitive increases in PKC‐induced phosphorylation, as detected by CKAR in the cytoplasm or plasma membrane. The CKAR responses lasted for several minutes in both the cytoplasm and plasma membrane then returned to baseline values before subsequent Ca2+ transients. High frequency oscillations caused by PLCζ led to an integration of PKC‐induced phosphorylation. The conventional PKC inhibitor, Gö6976, could inhibit CKAR increases in response to thapsigargin or ionomycin, but not the repetitive responses seen at fertilization. Repetitive increases in PKCδ activity were also detected during Ca2+ oscillations using an isoform‐specific δCKAR. However, PKCδ may already be mostly active in unfertilized eggs, since phorbol esters were effective at stimulating δCKAR only after fertilization, and the PKCδ‐specific inhibitor, rottlerin, decreased the CKAR signals in unfertilized eggs. These data show that PKC‐induced phosphorylation outlasts each Ca2+ increase in mouse eggs but that signal integration only occurs at a non‐physiological, high Ca2+ oscillation frequency. The results also suggest that Ca2+‐induced DAG formation on intracellular membranes may stimulate PKC activity oscillations at fertilization. J. Cell. Physiol. 228: 110–119, 2013. © 2012 Wiley Periodicals, Inc.
Angiotensin type 1 receptor autoantibody from preeclamptic patients induces human fetoplacental vasoconstriction
Authors: Zhang Suli , Zheng Ronghua , Yang Lihong , Zhang Xi , Zuo Lin , Yang Xiaoli , Bai Kehua , Song Li , Tian Jue , Yang Jie , Liu Huirong 
Published: May 2012

AbstractIncreased vascular resistance in the fetoplacental circulation is a characteristic of preeclampsia. However, the potential molecular mechanisms of this condition remain obscure. The current study aimed to determine the direct effect of the peptide antigen corresponding to the second extracellular loop of the angiotensin II type 1 receptor (AT1R‐ECII) activating autoantibody (AT1‐AA), a novel risk factor in preeclamptic patients, on fetoplacental villus stem blood vessels. Immunohistochemistry revealed that AT1 receptors were localized in the veins and arteries of human placental villi. Among 58 serum samples from preeclamptic patients, 28 (48.28%) were proved AT1‐AA‐positive by enzyme‐linked immunosorbent assay [P < 0.01 vs. 2/51 (3.92%) in the normal pregnancy group]. Total IgGs purified from AT1‐AA‐positive patients' sera (AT1‐AA‐IgGs) were added to isolated normal human placental blood vessels. The IgG significantly constricted both the villus veins and arteries in a dose‐dependent manner in vitro, which could be blocked by the peptide corresponding to the human AT1R‐ECII, anti‐human IgG or the AT1 receptor antagonist losartan. Additionally, the venous constriction induced by AT1‐AA‐IgGs remained unchanged even at the end of the experiment (about half an hour), but the vasoconstriction caused by the AT1 receptor agonist angiotensin II underwent desensitization within three minutes. Collectively, our results demonstrated that AT1‐AA in preeclamptic sera can directly constrict fetoplacental villus blood vessels without desensitization via the AT1 receptor in vitro, which might contribute to poor fetoplacental perfusion in preeclampsia. J. Cell. Physiol. 228: 142–148, 2013. © 2012 Wiley Periodicals, Inc.
Acute appendagitis of the ligamentum teres hepatis: Clinical, ultrasound, and computed tomographic findings
Authors: Nolthenius Charlotte J. Tutein , Bruinsma Wendy E. , Knook M. T. T. , Puylaert Julien B. C. M. 
Published: May 2012

AbstractPurpose.To describe the clinical, ultrasound (US), and CT findings in three patients with acute appendagitis of the ligamentum teres hepatis.Methods.A retrospective search of cases over a 4‐year period was performed and yielded three patients with acute appendagitis of the ligamentum teres hepatis. The diagnosis was confirmed by US, CT, and clinical follow‐up in all three cases. We retrospectively noted the laboratory data, clinical findings, and presumptive clinical diagnosis and describe the US and CT findings.Results.All three patients presented with severe, circumscribed epigastric pain without other symptoms. The complex reactive protein was not elevated or only mildly elevated. At the spot of maximum pain, US and CT showed all signs of an acute appendagitis; however, the pain was not close to colon, but close to the teres ligament. Symptoms resolved within 1 to 2 weeks without therapy.Conclusions.Acute appendagitis of the teres ligament is not as rare as previously assumed. Familiarity with the US and CT features enables a reliable diagnosis and prevents unnecessary medical or operative treatment. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2013
Cerebrovascular response to valsalva maneuver: Methodology, normal values, and retest reliability
Authors: Wallasch Thomas‐Martin , Kropp Peter 
Published: May 2012

AbstractPurpose.To provide reference values of cerebrovascular reactivity measured with transcranial Doppler ultrasonography in response to rapid changes in blood pressure during the late straining phase (IIb) of a Valsalva maneuver (VM).Methods.Middle cerebral artery blood flow velocity, arterial blood pressure changes, and end‐tidal partial carbon dioxide pressure (pCO2) concentrations were simultaneously and noninvasively measured in 60 healthy subjects. Centro‐peripheral Valsalva ratio was calculated by the quotient of cerebrovascular reactivity and peripheral arterial blood pressure response to VM during phase IIb. Age dependency and short‐ and long‐term reliability of indices were evaluated. Correlation between the autonomic response and changes of pCO2 was calculated.Results.Centro‐peripheral Valsalva ratio was higher in younger healthy subjects, whereas peripheral autonomic reactivity appeared age‐independent. There was no correlation between dynamic autoregulatory response and pCO2. Short‐ and long‐term measurements of autoregulatory indices showed excellent reliability.Conclusions.VM is a suitable maneuver to evaluate dynamic autonomic response using transcranial Doppler ultrasonography and noninvasive arterial blood pressure monitoring. Autonomic response during VM does not depend on pCO2. Normal human subjects show age‐dependent centro‐peripheral autoregulatory response. 2012 Wiley Periodicals, © Inc. J Clin Ultrasound, 2012
Liver MRI and histological correlates in chronic liver disease on multiphase gadolinium‐enhanced 3D gradient echo imaging
Authors: Martin Diego R. , Lauenstein Thomas , Kalb Bobby , Lurie Christina , Kitajima Hiroumi , Sharma Puneet , Salman Khalil , Moreira Roger , Farris Alton B. , Spivey James , Martinez Enrique , Hanish Steve , Adsay Volkan 
Published: May 2012

AbstractPurpose:To evaluate intrinsic hepatic enhancement patterns on multiphase, gadolinium‐enhanced, fat‐suppressed, 3D T1‐weighted, gradient echo magnetic resonance imaging (MRI) as a quantitative correlate for severity of pathological changes in chronic liver disease (CLD).Materials and Methods:This study was HIPAA‐compliant and Institutional Review Board‐approved. In all, 75 patients were studied by contrast‐enhanced multiphase abdominal MRI. CLD patients had liver histology correlation derived from right lobe liver biopsies. Contrast‐enhanced arterial‐ and delayed‐phase 3D gradient recalled echo (GRE) liver MRI were scored using feature categorization templates to quantify enhancement patterns by three independent readers. Liver histopathology was staged/graded for fibrosis/inflammation using the Scheuer system. Statistical testing for MRI histology correlates used a Pearson's product moment correlation and a Wilcoxon–Mann–Whitney two‐sample rank‐sum test. Reader agreement was analyzed by a modified Fleiss' kappa test.Results:MRI histology correlation was high for delayed‐phase MRI versus fibrosis stage (95% confidence interval [CI] 0.941 < r < 0.976, P = 5 × 10−7), but lower for all other comparisons (delayed‐phase vs. inflammation and arterial‐phase vs. inflammation or fibrosis all showed a CI no greater than 0.64). Paired testing between delayed‐phase MRI score and histology fibrosis staging incremental levels was significant (from P < 10−2 to P < 10−5).Conclusion:A standard gadolinium‐enhanced liver MRI may provide a correlate measure of hepatic fibrosis over a spectrum of severity. J. Magn. Reson. Imaging 2012;36:422–429. © 2012 Wiley Periodicals, Inc.
Non‐contrast‐enhanced MRI of the pulmonary blood volume using two‐compartment‐modeled T1‐relaxation
Authors: Gaass Thomas , Dinkel Julien , Bauman Grzegorz , Zaiss Moritz , Hintze Christian , Haase Axel , Laun Frederik 
Published: May 2012

AbstractPurpose:To introduce a novel technique, based on a two‐compartment model and nonselective inversion recovery (TCIR) for the non‐contrast‐enhanced evaluation of the fractional pulmonary blood volume (fPBV).Materials and Methods:Ten healthy volunteers and one patient with focal lung destruction underwent examination with conventional magnetic resonance imaging (MRI) and TCIR. The reproducibility of TCIR was evaluated statistically, analyzing three consecutive measurement series. In order to evaluate the sensitivity of TCIR, the influence of gravitation on fPBV values along the anterior–posterior direction was assessed. Therefore, two transverse parameter maps of each volunteer in supine and prone position were acquired and analyzed. A comparison of patient images from TCIR‐MRI, dynamic contrast‐enhanced (DCE) MRI, and contrast‐enhanced computed tomography (CT) was performed visually.Results:The statistical evaluation showed significant similarity within the volunteer group, proving reproducibility. The detected slope of the fPBV values in anterior–posterior direction for both supine and prone position demonstrated the sensitivity of TCIR to the gravitational effect on the pulmonary blood distribution. The comparison between CT, DCE‐, and TCIR‐MRI patient datasets showed high similarity in dimension and location of the pathological part of the lung parenchyma.Conclusion:The introduced TCIR‐technique is able to provide reproducible maps of the fPBV without the application of intravenous contrast media. J. Magn. Reson. Imaging 2012;36:397–404. © 2012 Wiley Periodicals, Inc.
Feasibility of in ovo diffusion tractography in the chick embryo using a dual‐cooling technique
Authors: Zhou Zien , Xu Jianrong , DelProposto Zachary S. , Hua Jia , Fan Yunshu , Zhang Zishu , Ye Yongquan , Haacke E.Mark , Hu Jiani 
Published: May 2012

AbstractPurpose:To evaluate the capability of a dual‐cooling technique in suppressing motion artifact and to evaluate the feasibility of the noninvasive muscle fibers tracking using DTI during chick embryonic development.Materials and Methods:Fifteen eggs were divided into three groups of 5 eggs each (one group for each imaging sequence), and eggs were imaged every 48 h from incubation day 4; embryos were imaged in ovo using three sequences of varying duration (T1, T2, and DTI). For each sequence, three preprocessing methods were used: no‐cooling (NC), single‐cooling (SC), and dual‐cooling (DC). Two independent observers assessed images for motion artifact. The results of different preprocessing methods used for each sequence were compared by the χ2 test. The Cohen kappa test was used to assess the interobserver variability.Results:For T1 imaging, motion artifact was adequately suppressed by both SC and DC methods (χ2 test; P > 0.05). For T2 imaging, motion artifact was also sufficiently suppressed by both SC and DC methods (χ2 test; P > 0.05) except incubation day 19 (χ2 test; P < 0.001). For DTI, motion artifact was less with DC than SC after 8 days (χ2 test; P < 0.05). Hindlimb muscle fibers of chick embryo could be serially evaluated with DTI from 8 days using dual‐cooling technique.Conclusion:The dual‐cooling technique enables DTI of chick embryo in ovo with minimal motion artifact, which permits muscle fiber tracking by DTI during chick embryonic development possible, and can improve the imaging quality of conventional MRI with long duration and those sensitive to motion. J. Magn. Reson. Imaging 2012;36:993–1001. © 2012 Wiley Periodicals, Inc.
The devil without and within: A conceptual model of social cognitive processes whereby discrimination leads stigmatized minorities to become discouraged workers
Authors: Heslin Peter A. , Bell Myrtle P. , Fletcher Pinar O. 
Published: May 2012

SummaryIn contrast to the substantial literatures on job loss, underemployment, and re‐employment, management scholars have paid scant attention to “discouraged workers,” defined as those who want to work but have ceased looking for work because of labor market‐related reasons such as discrimination. Drawing together the labor economics category of discouraged workers, the diversity literature on employment discrimination, and social cognitive research on careers, we model social cognitive mechanisms whereby discrimination can lead stigmatized minorities to become discouraged workers. We show how direct effects of discrimination (the “devil without”) can be compounded by its indirect impacts—through minority socialization and identity, struggling role models, learned helplessness, and low job search self‐efficacy (collectively, the “devil within”)—to lead stigmatized minorities to become discouraged workers. Our model of insidious intra‐ and inter‐personal dynamics that can amplify and sustain the demoralization and exclusion that stems from discrimination has implications for researchers, organizations, and those concerned with helping discouraged workers. Copyright © 2012 John Wiley & Sons, Ltd.
Clinical use of a neck brace to improve hands‐free speech in laryngectomized patients
Authors: Dirven Richard , Kooijman Piet G. C. , Wouters Yannick , Marres Henri A. M. 
Published: May 2012

AbstractObjectives/Hypothesis:Time of adherence of adhesive baseplate housings to the neck of a laryngectomized patient is one of the main problems that account for the low number of laryngectomy patients who benefit from hands‐free speech. An external neck brace (ENB 1.0) was introduced to support peristomal fixation of adhesive baseplates.Study Design:A prospective randomized controlled clinical cross‐over trial.Methods:A total of 28 laryngectomy patients participated in this randomized, prospective, crossover trial. All used the Provox hands‐free heat and moisture exchanger (HME) valve for 1 month: 2 weeks with an ENB and 2 weeks without.Results:The median lifetime of an adhesive baseplate without a brace was 52.5 minutes versus 210 minutes with a brace (P = .03). Four participants considered the ENB as “a little” bit of a welcome addition, nine as “quite a bit,” and six as “very much” (79%) to improve hands‐free speech.Conclusions:The ENB significantly increases the lifetime of an adhesive baseplate and therefore contributes to achieving hands‐free speech for a greater number of patients with laryngectomy. Laryngoscope, 2012