bluuebunny/crossref_metadata_2025 huggingface dataset:
Osteoblastic potency of bone marrow cells cultivated on functionalized biometals with cyclic RGD‐peptide
Authors: Jäger M. , Böge C. , Janissen R. , Rohrbeck D. , Hülsen T. , Lensing‐Höhn S. , Krauspe R. , Herten M.
Published: March 2013

The fixation of cementless endoprostheses requires excellent fixation at the bone implant interface. Although the surface structures of these implants are designed to promote osteoblastic differentiation, poor bone quality may prevent or delay osseointegration. There is evidence that RGD peptides known as recognition motifs for various integrins, promote cellular adhesion, influence cellular proliferation, and differentiation of local cells. In this study, five different metal surfaces were analyzed: Sandblasted (TiSa) and polished (TiPol) Ti6Al4V, porocoated (CCPor) and polished (CCPol) cobalt chrome and polished stainless steel (SS) were coated by ethanol amine and poly(ethylene glycol) to attach covalently RGD peptides. Human mesenchymal stromal cells of healthy donors were cultivated onto prior functionalized metal surfaces for 14 days without osteogenic stimulation. Cell proliferation and differentiation were quantitatively evaluated for native (I), NaOH pre‐activated (II), NaOH pre‐activated, and PEG‐coated (III) as well as for RGD (IV) coated surfaces. The RGD immobilization efficiency was analyzed by epi‐fluorescence spectroscopy, cell morphology was documented by light and scanning electron microscopy. The RGD‐binding efficiency was TiSa > TiPol > SS > CCPor > CCPol. RGD coated surfaces showed the highest average cell proliferation on CCPol > SS > CCPor > TiSa ≥ TiPol, whereas cellular differentiation mostly correlated with the observed proliferation results, such as CCPol > TiSa > SS > CCPor > TiPol. Considering statistical analyses (significance level of α = 0.05), the RGD‐coating of all biometals in comparison and in respect of their particular controls showed no significant improvement in cellular proliferation and osteoblastic differentiation. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 2905–2914, 2013.
Toward mucoadhesive hydrogel formulations for the management of xerostomia: The physicochemical, Biological, and Pharmacological Considerations
Authors: Tsibouklis John , Middleton Andrew M. , Patel Nisha , Pratten Jonathan
Published: March 2013

Although hydrogel formulations that may be applied to many mucosal surfaces are now readily accessible, little research effort has been concentrated on the development of systems that may be usefully employed for the prolonged hydration of the oral cavity. To this end, and set within the context of oral care in general, this review considers the requirements for the design of hydrogel formulations with an affinity for buccal cells and details methods for evaluating the performance of these formulations as treatments for the management of xerostomia. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3327–3338, 2013.
Biological evaluation of materials for cardiovascular application: The role of the short‐term inflammatory response in endothelial regeneration
Authors: Boccafoschi F. , Mosca C. , Ramella M. , Carmagnola I. , Chiono V. , Ciardelli G. , Cannas M.
Published: March 2013

Because of their suitable bio‐mechanical properties, polymeric materials, such as Poly(L‐lactic acid) (PLLA), and poly (lactic‐co‐glycolic acid) (PLGA), are often used in the biomedical field, in particular for cardiovascular applications. Implanted materials induce several events related to the inflammatory reaction, such as macrophage adhesion and activation with following cytokine release. This work considered the effect of macrophage adhesion and related cytokine release on endothelial cells (PAOEC) proliferation and migration. Slight differences have been shown by the macrophages reaction when in contact with PLLA, PLGA, or PLLA/PLGA blend. However, these differences showed to differently enhance endothelial cells behavior in terms of wound healing. These data suggest the inflammatory reaction as a useful way to consider concerning materials biocompatibility, in order to optimize the endothelial regeneration following vascular prosthetic implants. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 3131–3140, 2013.
Icariside II Reduces Testosterone Production by Inducing Necrosis in Rat Leydig Cells
Authors: Liu Jinwen , Li Weixuan , Piao Xiaoyu , Zhang Junwen , Zhang Dongzhi , Wei Ning , Hu Defu , Liu Shuqiang
Published: March 2013

The present study demonstrates that Icariside II (10, 20, and 40 µM) reduced Leydig cell testosterone production and cell viability in a concentration‐ and time‐dependent manner. Hoechst 33342/propidium iodide staining indicated that no morphological changes in Leydig cell nuclear chromatin occurred, caspase‐3 expression also showed no significant change, but cell death was caused by the 10‐µM Icariside II treatment. Furthermore, a significant reduction in NAD+ levels was observed following Icariside II exposure (10, 20, and 40 µM). Cell death was avoided when Icariside II treated cells were incubated with extracellular NAD+ (5 and 10 mM). Moreover, the addition of NAD+ (5 and 10 mM) could restore ATP production and prevent cell death. The results suggest that Icariside II can reduce testosterone production by inducing necrosis, but not apoptosis, in rat Leydig cells. This mechanism may also account for the Icariside II induced depletion of NAD+ and ATP levels. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:243‐250, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21481
RING finger protein 10 regulates retinoic acid‐induced neuronal differentiation and the cell cycle exit of P19 embryonic carcinoma cells
Authors: Malik Yousra S. , Sheikh Muhammad A. , Lai Mingming , Cao Rangjuan , Zhu Xiaojuan
Published: March 2013

Rnf10 is a member of the RING finger protein family. Recently, a number of RING finger proteins were reported to be involved in neuronal differentiation, development, and proliferation. In this study, we observed that the mRNA levels and protein expression of Rnf10 increase significantly upon the retinoic acid‐induced neuronal differentiation of P19 cells. Knockdown of Rnf10 by RNA interference significantly impaired neuronal differentiation of P19 cells by attenuating the expression of neuronal markers. Cell cycle profiling revealed that Rnf10‐depleted cells were unable to establish cell cycle arrest after RA treatment. In agreement with flow cytometry analysis, increased cell proliferation was observed after RA induction in Rnf10 knockdown cells as determined by a BrdU incorporation assay. Moreover, like Rnf10, the mRNA levels and protein expression of p21 and p27 also increased upon RA induction. Rnf10 knockdown only resulted in a reduction of p21 expression, while p27 and p57 expression remained unchanged, indicating that Rnf10 may regulate cell cycle exit through the p21 pathway. Ectopic p21 expression partially rescued the effect of Rnf10 depletion on the neuronal differentiation of P19 cells. Collectively, these results showed that increase in Rnf10 expression upon RA induction is necessary for the positive regulation of cyclin kinase inhibitor p21 expression, which leads to cell cycle arrest and is critical for neuronal differentiation. J. Cell. Biochem. 114: 2007–2015, 2013. © 2013 Wiley Periodicals, Inc.
Virtual bioreactor cultivation for operator training and simulation: application to ethanol and protein production
Authors: Gerlach Inga , Hass Volker C. , Brüning Simone , Mandenius Carl‐Fredrik
Published: March 2013

BACKGROUND

During recent years several computer‐based operator training simulators (OTS) have been developed that are suitable for the virtual training of operators and other professionals. In the field of bioprocess engineering OTS are rarely used. Furthermore, the effects of using training simulators in bioprocess applications have not been evaluated.

RESULTS

The OTS BioProcessTrainer was applied to bioreactor operations for two biological processes, Saccharomyces cerevisiae, for ethanol production, and recombinant Escherichia coli, for production of green fluorescence protein (GFP). The simulator used a multi‐shell model platform that described the biological and physical conditions of the bioreactor for the two bioprocess systems. The simulator enabled the user to plan, operate and control the processes in real or accelerated time. The training resulted in improved ability to manage the whole bioreactor procedure for the two processes.

CONCLUSION

The study showed that the simulator can be an efficient tool for training of operation, optimization and control of bioprocesses. The mathematical model framework of the simulator can be adapted to a variety of industrial bioprocesses. Thus, it appears likely that this type of OTS may serve as a useful resource in industry for training and continuing education of plant operators and engineers. © 2013 Society of Chemical Industry
A pH‐responsive drug release system based on doxorubicin conjugated amphiphilic polymer coated quantum dots for tumor cell targeting and tracking
Authors: Yang Bohan , Li Yapeng , Sun Xiaoran , Meng Xinlei , Chen Peng , Liu Nian
Published: March 2013

BACKGROUND

A tumor‐targeted and pH‐responsive drug release system based on poly(ethylene glycol) (PEG) and dodecylamine (DDA)‐modified poly itaconic acid (PIA) with doxorubicin (DOX) and quantum dots (QDs) (PIA‐PEG‐DDA‐DOX@QDs) has been constructed successfully. These nanocomposites with outstanding capabilities were further designed to target liver cancer cells with vascular endothelial growth factor receptor (VEGFR) overexpressed.

RESULTS

The nanoparticles constructed were spherical and monodispersed with very small diameter. The cumulative release rates of DOX conjugates were studied at pH 5.5 and pH 7.4, and the release behavior at pH 5.5 fit the first‐order kinetics model, Q=46.5991 –45.2394e‐0.24355t for PIA‐PEG‐DDA‐DOX and Q=46.7094–38.5588e‐0.20123t for PIA‐PEG‐DDA‐DOX@QDs. The nanoparticles show low cytotoxicity at pH 7.4 and high cytotoxicity at pH 5.5 in cell viability studies. In the intracellular localization observation, the targeting molecule anti‐VEGF conjugated NPs exhibited efficient receptor‐mediated endocytosis in anti‐VEGF receptor‐overexpressing cancer cells, compared with nontargeted nanoparticles.

CONCLUSIONS

The targeting imaging and pH‐responsive drug release system could target the tumor cells and fluoresce quantum dots sensitively due to the conjugation of VEGF, and enabled pH‐controlled‐activation of the DOX. The water soluble conjugates have the potential of becoming a promising diagnostic tool in clinical application for cancer detection and treatment. © 2013 Society of Chemical Industry
Field measurement of basal forces generated by erosive debris flows
Authors: McCoy S. W. , Tucker G. E. , Kean J. W. , Coe J. A.
Published: March 2013

It has been proposed that debris flows cut bedrock valleys in steeplands worldwide, but field measurements needed to constrain mechanistic models of this process remain sparse due to the difficulty of instrumenting natural flows. Here we present and analyze measurements made using an automated sensor network, erosion bolts, and a 15.24 cm by 15.24 cm force plate installed in the bedrock channel floor of a steep catchment. These measurements allow us to quantify the distribution of basal forces from natural debris‐flow events that incised bedrock. Over the 4 year monitoring period, 11 debris‐flow events scoured the bedrock channel floor. No clear water flows were observed. Measurements of erosion bolts at the beginning and end of the study indicated that the bedrock channel floor was lowered by 36 to 64 mm. The basal force during these erosive debris‐flow events had a large‐magnitude (up to 21 kN, which was approximately 50 times larger than the concurrent time‐averaged mean force), high‐frequency (greater than 1 Hz) fluctuating component. We interpret these fluctuations as flow particles impacting the bed. The resulting variability in force magnitude increased linearly with the time‐averaged mean basal force. Probability density functions of basal normal forces were consistent with a generalized Pareto distribution, rather than the exponential distribution that is commonly found in experimental and simulated monodispersed granular flows and which has a lower probability of large forces. When the bed sediment thickness covering the force plate was greater than ∼ 20 times the median bed sediment grain size, no significant fluctuations about the time‐averaged mean force were measured, indicating that a thin layer of sediment (∼ 5 cm in the monitored cases) can effectively shield the subjacent bed from erosive impacts. Coarse‐grained granular surges and water‐rich, intersurge flow had very similar basal force distributions despite differences in appearance and bulk‐flow density. These results demonstrate that debris flows can have strong control on rates of steepland evolution and contribute to a foundation needed for modeling debris‐flow incision stochastically.
High magnitude and rapid incision from river capture: Rhine River, Switzerland
Authors: Yanites Brian J. , Ehlers Todd A. , Becker Jens K. , Schnellmann Michael , Heuberger Stefan
Published: March 2013

Landscape evolution is controlled by the development and organization of drainage basins. As a landscape evolves, drainage reorganization events can occur via river capture or piracy, whereby one river basin grows at the expense of another. The river downstream of a capture location will generate a transient topographic response as the added water discharge increases sediment transport and erosion efficiency. This erosional response will propagate upstream through both the captured and original river basins. Here we focus on quantifying the impact of drainage reorganization along the Rhine/Aare River system (~45,000 km2) during the late Pliocene/early Pleistocene, where gravel remnants indicate total incision of ~650 m during the last ~4.2 Myr in the region of the recent Aare‐Rhine confluence. We develop a numerical model of drainage capture to quantify the range of possible magnitudes of erosion and the transient river response resulting from the reorganization of the Rhine River. The model accounts for both fluvial incision and sediment transport. Our model estimates 400–800 m of river elevation change (lowering profiles) during the last ~4 Myr due to river capture events, providing an important component to the recent exhumation budget of the Swiss Alpine Foreland. The model indicates a rapid response to capture events (re‐equilibration timescale of ~1 Myr). The predicted incision magnitudes are consistent with incision measured from the elevation of Pliocene and early Pleistocene river gravels, suggesting that across northern Switzerland, a significant amount of incision can be explained by drainage reorganization.
Incidence of cholinesterase inhibitor therapy initiation among hospitalized patients
Authors: Swan Joshua T. , Wagle Kamal C. , Thompson‐Moore Nathaniel , Taffet George E.
Published: March 2013

BACKGROUND

Initiation of cholinesterase inhibitor (ChEI) therapy for delirium during hospitalization is ineffective and may be associated with increased morbidity and mortality.

OBJECTIVE

To describe the incidence of initiating ChEI therapy during hospitalization.

DESIGN

A retrospective cross‐sectional study.

SETTING

A tertiary‐care academic medical center.

PATIENTS

Inpatient admissions from September 2010 through March 2011 with ChEI administration.

INTERVENTION

None.

MEASUREMENTS

Incidence of ChEI exposure, initiation of ChEI therapy, initiation of antipsychotics and benzodiazepines, infection, in‐hospital mortality, and hospital length of stay.

RESULTS

The incidence of adult admissions with ChEI exposure and ChEI initiation was 23.2 (95% confidence interval: 21.2–25.4) and 2 (95% confidence interval 1.5‐2.8) per 1000 admissions, respectively. Of 476 admissions receiving ChEI, 9% (n = 42) initiated therapy during the hospital stay and 91% (n = 434) continued on previously started therapy. Patients initiated on ChEI therapy frequently had infection (20 of 42) and were commonly initiated on antipsychotics (14 of 42) and benzodiazepines (13 of 42). Patients were hospitalized for a median of 2 days (interquartile range, 1–4) before initiation of ChEI and were exposed to therapy for a median of 3 days (interquartile range, 2–6). Of the 41 patients discharged from the hospital, 90% (n = 37) had orders to continue the ChEI postdischarge.

CONCLUSIONS

Despite a lack of evidence to support the practice, 9% of patients who received ChEI therapy were initiated during the inpatient setting. These patients were not routinely screened for delirium and frequently received treatments associated with delirium. Journal of Hospital Medicine 2013;8:304–308. © 2013 Society of Hospital Medicine.
Clinical and technical considerations for high quality breast MRI at 3 tesla
Authors: Rahbar Habib , Partridge Savannah C. , DeMartini Wendy B. , Thursten Bonnie , Lehman Constance D.
Published: March 2013

The use of breast MRI at 3 tesla (T) has increased in use substantially in recent years. Potential benefits of moving to higher field strength MRI include improved morphologic and kinetic assessment of breast lesions through higher spatial and temporal resolution dynamic contrast‐enhanced MR examinations. Furthermore, higher field strength holds promise for the development of superior advanced breast MRI techniques, such as diffusion weighted imaging and MR spectroscopy. To fully realize the benefits of moving to 3T, a thorough understanding of the technical and safety challenges of higher field strength imaging specific to breast MRI is paramount. Through the use of advanced coil technology, parallel imaging, dual‐source parallel radiofrequency excitation, and image‐based shimming techniques, many of these limiting technical factors can be overcome to achieve high quality breast MRI at 3T. J. Magn. Reson. Imaging 2013;37:778–790. © 2012 Wiley Periodicals, Inc.
Pretherapeutic MRI for decision‐making regarding selective neoadjuvant radiochemotherapy for rectal carcinoma: Interim analysis of a multicentric prospective observational study
Authors: Ptok Henry , Ruppert Reinhard , Stassburg Joachim , Maurer Christoph Andreas , Oberholzer Katja , Junginger Theodor , Merkel Susanne , Hermanek Paul
Published: March 2013

Purpose:

To study the accuracy of different cutoffs for an involved circumferential resection margin (CRM) compared with T and N categories measured by MRI as basis for selective application of neoadjuvant radiochemotherapy (nRCT) in rectal carcinoma.

Materials and Methods:

In a prospective multicenter observational study involving 153 primarily operated patients, the preoperative results of MRI with pathohistological findings of resected specimens were compared.

Results:

For a cutoff of ≤1 mm for involvement of the CRM, the accuracy of preoperative MRI was 90.9% (139/153). The negative predictive value was 98.5% (134/136). The four participating departments did not differ significantly. For a cutoff of >2 mm and >5 mm, the rates of false‐positive findings increased significantly from 5% to 12% and 35% with a decrease in accuracy to 82% and 62%, respectively. In contrast, the accuracy in predicting T (69.3%) and N categories (61.4%) was much lower.

Conclusion:

The indication for nRCT should be based on the determination of the minimal distance of the tumor from mesorectal fascia with a cutoff point of >1 mm as measured by MRI. J. Magn. Reson. Imaging 2013;37:1122–1128. © 2013 Wiley Periodicals, Inc.
Predictive value of apparent diffusion coefficient in evaluation of colorectal carcinoma hepatic metastases' response to radiofrequency ablation
Authors: Szurowska Edyta , Nowicki Tomasz K. , Izycka‐Swieszewska Ewa , Zadrozny Dariusz , Markiet Karolina , Studniarek Michal
Published: March 2013

Purpose

To establish the apparent diffusion coefficient (ADC) suitability to evaluate the radiofrequency ablation (RFA) outcome in patients with chemotherapy resistant or partially responding colorectal adenocarcinoma liver metastases.

Materials and Methods

A total of 56 patients with 116 metastatic foci over 10 mm in diameter were examined with 1.5 Tesla MRI scanner 1 day before percutaneous RFA treatment. Lesions were evaluated in echo‐planar diffusion‐weighted images with b = 0, 15 and 500 s/mm2. On basis of computed tomography scan at 6 weeks, 3 and 6 months after RFA and serum CEA (carcinoembryonic antigen) level lesion were recognized as responding or nonresponding lesions. ADC values for b = 0–15 and 0–500 s/mm2 of responding and nonresponding lesions were compared.

Results

Noncomplete ablation concerned 28 lesions. Mean pretreatment ADC values for b = 0–15 and 0–500 s/mm2 of responding metastases were significantly lower (2.14 and 1.48 × 10−3 mm2/s) than those of nonresponding tumors (2.7 and 1.74 × 10−3 mm2/s). Sensitivity, specificity, and accuracy of ADC values for b = 0–15 s/mm2 were 79 (95%CI = 59–92), 85 (95%CI = 76–92), 84%; and for b = 0–500 s/mm2, the efficacy parameters were, respectively, 78 (95%CI = 56–92), 78 (95%CI = 67–86), and 78%. The P value was under 0.001 for both b parameters.

Conclusion

The pretreatment ADCs values of chemotherapy resistant or partially responding colorectal adenocarcinoma liver metastatic lesion can be predictive factor of tumors response to RFA therapy. J. Magn. Reson. Imaging 2013;38:1027–1032. © 2013 Wiley Periodicals, Inc.
Life‐long aerobic exercise preserved baseline cerebral blood flow but reduced vascular reactivity to CO2
Authors: Thomas Binu P. , Yezhuvath Uma S. , Tseng Benjamin Y. , Liu Peiying , Levine Benjamin D. , Zhang Rong , Lu Hanzhang
Published: March 2013

Purpose

To examine the potential benefits of life‐long aerobic exercise on brain health, in particular cerebrovascular function.

Materials and Methods

Ten Masters athletes (MA) (seven males, three females; 74.5 ± 5.8 years) and 10 sedentary elderly individuals (SE) (eight males, two females; 75.4 ± 5.6 years) were recruited and baseline cerebral blood flow (CBF) and cerebral vascular reactivity (CVR) to CO2 were measured on a 3T MRI scanner. Nine sedentary young subjects were also recruited to serve as a control group to verify the age effect.

Results

When compared to the SE group, MA showed higher CBF in posterior cingulate cortex/precuneus, which are key regions of the default‐mode‐network and are known to be highly sensitive to age and dementia. CVR in the MA brains were paradoxically lower than that in SE. This effect was present throughout the brain. Within the MA group, individuals with higher VO2max had an even lower CVR, suggesting a dose–response relationship.

Conclusion

Life‐long aerobic exercise preserved blood supply in the brain's default‐mode‐network against age‐related degradation. On the other hand, its impact on the cerebral vascular system seems to be characterized by a dampening of CO2 reactivity, possibly because of desensitization effects due to a higher lifetime exposure. J. Magn. Reson. Imaging 2013;38:1177–1183. © 2013 Wiley Periodicals, Inc.
Robotic‐assisted FAMM flap for soft palate reconstruction
Authors: Bonawitz Steven C. , Duvvuri Umamaheswar
Published: March 2013

Objectives/Hypothoses:

TORS (Trans Oral Robotic Surgery) has been demonstrated to be an acceptable alternative to chemoradiation for the treatment of early stage malignant lesions of the oropharynx, with equivalent tumor control and enhanced functional outcomes. Surgical ablation of tumors of the oropharynx under conditions of limited access, however, creates the need to adapt the robotic platform to surgical reconstruction and to assess reconstructive outcomes. We present our experience with the Facial Artery Musculomucosal (FAMM) flap with robotic assistance for the reconstruction of defects of the soft palate.

Methods:

We reviewed the records of five patients who underwent combined robot‐assisted resection of malignant lesions of the oropharynx with immediate reconstruction. The reconstructions included four ispilateral and one bilateral FAMM flaps. Patients were assessed for complications and functional results.

Results:

Successful closure of the defect was achieved in all five patients. There were no major complications; however, three patients developed minor wound dehiscence and two were revised at the time of planned subsequent lymphadenectomy. All five patients achieved a good functional outcome.

Conclusions:

The FAMM flap is reliable and easy to raise and transfer, with the surgical robot making it a good candidate for reconstruction of moderate‐sized defects created by TORS applied to malignancies of the soft palate. Minor wound dehiscence is not infrequent, but reconstructive outcomes are nevertheless good. A unilateral FAMM flap will reach to the contralateral border of the uvula and is best limited to defects with a width of 2 cm or less.
Use of lean sigma principles in a tertiary care otolaryngology clinic to improve efficiency
Authors: Lin Sandra Y. , Gavney Dean , Ishman Stacey L. , Cady‐Reh Julie
Published: March 2013

Objectives/Hypothesis

To apply Lean Sigma, a quality‐improvement strategy supported by tactical tools to eliminate waste and reduce variation, to improve efficiency of patient flow in a large tertiary otolaryngology clinic. The project goals were to decrease overall lead time from patient arrival to start of interaction with care provider, improve on‐time starts of patient visits, and decrease excess staff/patient motion.

Study Design

Prospective observational study.

Methods

Patient flow was mapped through the clinic, including preregistration processes. A time‐stamp observation study was performed on 188 patient visits over 5 days. Using Lean Sigma principles, time stamps were analyzed to identify patient flow constraints and areas for potential interventions. Interventions were evaluated and adjusted based on feedback from shareholders: removal of bottlenecks in clinic flow, elimination of non–value added registration staff tasks, and alignment of staff hours to accommodate times of high patient census. A postintervention time observation study of 141 patients was performed 5 months later.

Results

Patient lead time from clinic arrival to exam start time decreased by 12.2% on average (P = .042). On‐time starts for patient exams improved by 34% (χ2 = 16.091, P < .001). Excess patient motion was reduced by 74 feet per patient, which represents a 34% reduction in motion per visit.

Conclusions

Use of Lean Sigma principles in a large tertiary otolaryngology clinic led to decreased patient wait time and significant improvements in on‐time patient exam start time. Process mapping, engagement of leadership and staff, and elimination of non–value added steps or processes were key to improvement.

Level of Evidence

4. Laryngoscope, 123:2643–2648, 2013
Soil Structural Stability and Water Retention Characteristics Under Different Land uses of Degraded Lower Himalayas of North‐West India
Authors: Saha D. , Kukal S. S.
Published: March 2013

The lower Himalayan regions of north‐west India experienced a severe land‐use change in the recent past. A study was thus conducted to assess the effect of grassland, forest, agricultural and eroded land uses on soil aggregation, bulk density, pore size distribution and water retention and transmission characteristics. The soil samples were analysed for aggregate stability by shaking under water and water drop stability by using single simulated raindrop technique. The water‐stable aggregates (WSA) >2 mm were highest (17·3 per cent) in the surface layers of grassland, whereas the micro‐aggregates (WSA < 0·25 mm) were highest in eroded soils. The water drop stability followed the similar trend. It decreased with the increase in aggregate size. Being lowest in eroded soils, the soil organic carbon also showed an adverse effect of past land‐use change. The bulk density was highest in eroded lands, being significantly higher for the individual aggregates than that of the bulk soils. The macroporosity (>150 µm) of eroded soils was significantly (p < 0·05) lower than that of grassland and forest soils. The grassland soils retained the highest amount of water. Significant (p < 0·05) effects of land use, soil depth and their interaction were observed in water retention at different soil water suctions. Eroded soils had significantly (p < 0·05) lower water retention than grassland and forest soils. The saturated hydraulic conductivity and maximum water‐holding capacity of eroded soils were sufficiently lower than those of forest and grassland soils. These indicated a degradation of soil physical attributes due to the conversion of natural ecosystems to farming system and increased erosion hazards in the lower Himalayan region of north‐west India. Copyright © 2013 John Wiley & Sons, Ltd.
Update on donor-derived infections in liver transplantation
Authors: Echenique Ignacio A. , Ison Michael G.
Published: March 2013

Advances in surgical techniques, immunosuppressive medications, and robust infectious disease prophylaxis have resulted in liver transplantation becoming the treatment of choice for patients with end-stage liver disease and unresectable hepatocellular carcinoma. Nonetheless, organ transplantation is not without risk. Unexpected donor-derived disease transmission is a newly recognized risk that complicates approximately 0.2% of all organ transplants. We review the epidemiology of donor-derived infectious diseases and methods of risk mitigation with a focus on liver transplantation. Liver Transpl 19:575–585, 2013. © 2013 AASLD.
Error estimates for two‐level penalty finite volume method for the stationary Navier–Stokes equations
Authors: Huang Pengzhan , Feng Xinlong
Published: March 2013

Two‐level penalty finite volume method for the stationary Navier–Stokes equations based on the P1 − P0 element is considered in this paper. The method involves solving one small penalty Navier–Stokes problem on a coarse mesh with mesh size H = ϵ1 / 4h1 / 2, a large penalty Stokes problem on a fine mesh with mesh size h, where 0 < ϵ < 1 is a penalty parameter. The method we study provides an approximate solution with the convergence rate of same order as the penalty finite volume solution (uϵh,pϵh), which involves solving one large penalty Navier–Stokes problem on a fine mesh with the same mesh size h. However, our method can save a large amount of computational time. Copyright © 2013 John Wiley & Sons, Ltd.
Variational approach to some damped Dirichlet problems with impulses
Authors: Chen Huiwen , He Zhimin
Published: March 2013

In this paper, we study the existence of solutions for damped nonlinear impulsive differential equations with Dirichlet boundary conditions. By using critical point theory and variational methods, we give some new criteria to guarantee that the impulsive problems have at least one solution. Some recent results are extended and significantly improved. Finally, some examples are presented to illustrate our main results. Copyright © 2013 John Wiley & Sons, Ltd.
The deficit of lipid in cultured cells contrasted with clinical lipidomics
Authors: Lamaziere Antonin , Farabos Dominique , Wolf Claude , Quinn Peter J.
Published: March 2013

Cells grown in culture are frequently employed to model lipid metabolism in vivo. There are reasons of convenience for this but examination of the lipidome of cultured cells and their metabolic responses to lipid supplementation give cause to indicate disparity with their counterparts in living animals. The reason is mainly that homeostatic regulation is exercised in animals supplied with an adequate diet in which the adipose tissue and liver represent plentiful sources of lipid integrated via inter‐organ collaboration and able to buffer transient fluctuations in dietary lipid and essential fatty acids (EFAs). Moreover, conventional culture media are generally deficient in total lipids as well as essential EFAs. Cultured cells exposed to high glucose concentrations and lipid deficit typically manifest accelerated rates of lipogenesis evidenced by high rates of de novo FA biosynthesis. A more realistic model may be obtained by increasing supplements of lipid especially enriched in essential EFAs in the growth medium. Increasing concentrations of ω3 FAs, in particular, attenuate the rate of de novo lipogenesis. The improvement of cell culture models for pharmacological screening of drug‐candidates targeting lipid or glucose metabolism is highlighted.
High absorption terahertz‐wave absorber consisting of dual‐C metamaterial structure
Authors: Jiu‐Sheng Li
Published: March 2013

We report a perfect absorber based on dual‐C metamaterial structure operating in the terahertz regime.The proposed structure is numerically investigated by the CST Microwave Studio. By manipulating the periodic patterned structures as well as the dielectric layer material, significantly high absorption can be obtained at specific resonance frequency. The fabricated device has been characterized using a Fourier transform infrared spectrometer. The experimental results show that the distinct absorption peak at 0.573 THz with absorption magnitudes of 0.996, which is in good agreement with the simulation. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1185–1189, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27468
Linearization of stacked‐fet RF CMOS power amplifier using diode‐integrated bias circuit
Authors: Kong Jeongwoon , Jeong Jinho
Published: March 2013

In this article, the linearization circuit of stacked‐FET RF CMOS power amplifier (PA) is presented. The proposed diode‐integrated bias circuit provides the increasing DC gate bias current which allows the bottom FET in the tripled‐stacked FET to saturate at a higher power compared to the conventional bias circuit. The simulation shows that the proposed bias circuit can increase a 1‐dB gain compression point of the stacked‐FET PA with a higher efficiency. It is demonstrated from the measurement of the triple‐stacked CMOS PAs with W‐CDMA input signal that the proposed diode‐integrated bias circuit can reduce the spectrum regrowth and increase the average efficiency. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1011–1014, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27472
Broadband high‐gain Fabry–Perot cavity antenna with back radiation reduction
Authors: Ju Jeongho , Choi Jae Ick
Published: March 2013

A Fabry–Perot (FP) cavity antenna simultaneously producing a high‐gain, wide‐bandwidth, and high front‐to‐back ratio (FBR) is proposed. To reduce the back radiation, we enclosed all the openings of our antenna with folded metal walls having a length of approximately 0.2λ at a center frequency of 1.8 GHz, and to obtain a broader bandwidth and high gain, we employed a superstrate composed of double layered metal strip lines and placed over a feeder antenna. The antenna with folded metal walls compared to without folded metal walls yields a significant reduction in back radiation levels over the operating frequencies. An average suppression in back radiation of 20 dB was obtained, and a maximum gain value of 18.77 dBi has been measured over a 3 dB gain bandwidth of 24.1% (1.64–2.09 GHz). © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:975–978, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27474
Bandpass waveguide in 3D diamond‐structure EBG fabricated by stereolithography and gel casting
Authors: Chen Shibin , Li Dichen , Sun Kun , Han Haoxue
Published: March 2013

A waveguide located in a diamond photonic crystal (PC) is presented in this article. The alumina‐based three‐dimensional electromagnetic band gap crystal has been designed, optimized, and fabricated by the stereolithography combined with gel‐casting, which experimentally exhibited a large bandgap between 13.8 and 16.3 GHz with a relative width of 16.7%. Meanwhile, a waveguide located in such diamond structure has been designed and fabricated, which shows obvious bandpass between 13.8 and 15.5 GHz. Transmission properties of PCs waveguide will achieve their integration applications in standard microwave devices. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1145–1149, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27478
Compact circularly polarized circular microstrip tag antenna mountable on metallic surface
Authors: Kuo Shang‐Huang , Chen Horng‐Dean , Pan Shan‐Cheng , Tseng Yen‐Ming , Jheng Jing‐Lun
Published: March 2013

A compact circularly polarized circular microstrip tag antenna designed for RFID UHF band is presented.The proposed tag antenna is excited by using microstrip‐line coupling‐feed method. By choosing the proper lengths of two short‐circuited arc microstrip lines and its coupling distance, good complex impedance matching can be obtained. Moreover, a cross slot of unequal arm lengths embedded in a circular patch is used to achieve compact circularly polarized operation. The measured 10‐dB return‐loss bandwidth of the tag antenna is 40 MHz (901–941 MHz), while the 3‐dB axial‐ratio bandwidth is 6 MHz (912–918 MHz). Further experiment shows that the tag antenna can provide a significantly increased reading range when mounted on a metallic surface. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1107–1112, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27480
In‐line one‐pump parametric amplifier with independent polarization gain: A field‐trial demonstration
Authors: Marconi Jorge D. , Fugihara Meire C. , Callegari Fulvio A. , Fragnito Hugo L.
Published: March 2013

We present a one‐pump parametric amplifier with polarization independent gain working as an in‐line amplifier within an experimental field‐trial optical network. The polarization independent gain is obtained by using a polarization diversity technique (PDT). Five signals modulated at 10 Gb/s were transmitted through the network, and a gain variation as low as 0.05 dB, independent of the signal polarization, was obtained. The bit‐error‐rate (BER) for the amplified signals was measured. For a BER of 10−9, a power penalty as low as 0.7 dB is shown. These measurements were compared with the identical ones obtained when the parametric amplifier with the PDT was replaced by an Erbium‐doped fiber amplifier (EDFA). The fiber optical parametric amplifier (FOPA) with the PDT presents a power penalty of 0.7 dB in relation to the value obtained with the EDFA. These results show that parametric amplifiers that use the PDT are able to reach a performance comparable to those obtained with the current technology of optical amplifiers based on rare earth doped fibers. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1104–1107, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27481
Frequency‐ and time‐domain performance of a miniature planar ultra‐wideband antenna
Authors: Guo Lu , Chen Xiaodong
Published: March 2013

A miniature planar antenna for ultra‐wideband (UWB) applications is presented in this article. The proposed compact antenna consists of a quasi‐self‐complementary structure together with a tapered radiating slot. The optimal design of this type of antenna has been demonstrated to provide an ultrawide 10‐dB return loss bandwidth with satisfactory radiation properties. It also exhibits a fairly small dimension, 19 mm×16 mm in physical size and 0.19λ in electrical size, respectively. A parametric study is conducted to provide insights into the antenna operating mechanism. In addition, the time domain behavior of the proposed antenna is also examined. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1058–1065, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27483
A novel all‐fiber velocity interferometer with high fringe contrast
Authors: Hong Guangwei , Jia Bo , Xiao Qian , Tang Huang
Published: March 2013

A novel all‐fiber velocity interferometer with high fringe contrast (NAFVISAR) is proposed and demonstrated. The configuration of the AFVISAR utilizes PBS to remove the unwanted non‐interfering light beams from the moving target, which can approximately double the fringe visibility constant of the system compared with Levin's structure. With shaker vibration experiment, it is shown that the NAFVISAR achieved a fringe contrast of 0.91. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1029–1031, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27484
Design and performance of an HTS wideband microstrip bandpass filter at X‐band
Authors: Shang Zhaojiang , Guo Xubo , Cao Bisong , Zhang Xiaoping , Wei Bin , Heng Yong , Song Xiaoke , Suo Guannan , Wang Jingchen , Li Qirong
Published: March 2013

This article presents a 10‐pole high‐temperature superconducting (HTS) wideband microstrip bandpass filter with a novel configuration and compact size.The filter at 10 GHz with a fractional bandwidth of 40% is designed and fabricated on a 32.6 mm × 6.7 mm × 0.5 mm MgO substrate with double‐sided YBCO films. The internal couplings between quarter‐wavelength resonators are realized by parallel‐coupled microstrip line (PCML) structure and capacitive open‐ended stubs. The strong external couplings required by wideband filter are realized by impedance steps and capacitive stubs. The measured results at 55 K, without any tuning, show a high performance. The insertion loss is less than 0.31 dB, the return loss is better than −14 dB, and the out‐of‐band rejection is higher than 70 dB. The overall measurements are in good agreement with the simulations. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1027–1029, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27485
An isotropy dual‐band terahertz metamaterial
Authors: Li Biao , He Lianxing , Yin Yingzeng , Guo Wanyi , Sun Xiaowei
Published: March 2013

An isotropy terahertz (THz) metamaterial for dual‐band operation is designed and fabricated. The proposed metamaterial is composed of periodically arranged double metallic rings, and negative permittivity is obtained in 298–388 GHz and 652–780 GHz bands. Transmission and reflection characteristics of the proposed structure are simulated using Ansoft High Frequency Structure Simulator. The designed sample is fabricated on a gallium arsenide layer, and experiments are performed in THz time‐domain spectroscopy. The experimental results agree well with the simulations. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:988–990, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27486
Crescent slot antenna for 2.4/5.2/5.8 GHz wireless local area network operations
Authors: Lin Chun‐Cheng , Huang Chih‐Yu , Wang Bo‐Chun
Published: March 2013

A nonconcentric crescent slot antenna design for wireless local area network (WLAN) operation is proposed. The antenna has a single radiating slot for dual‐band operation and a simple feeding structure for impedance matching. It provides two 10‐dB impedance bandwidths of 115 MHz (ca. 4.7% centered at 2.45 GHz) and 1130 MHz (ca. 20.5% centered at 5.5 GHz). The nonconcentric crescent slot design covers the 2400–2484 and 5150–5825 MHz bands of WLAN operations. The return loss, radiation performance, and magnetic current distributions are studied and discussed. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1081–1085, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27491
Rectangular ring‐shaped dielectric resonator antenna for dual and wideband frequency
Authors: Khalily Mohsen , Rahim Mohamad Kamal A. , Murad Norasniza A. , Samsuri Nor Asmawati , Kishk Ahmed A.
Published: March 2013

A new modified planar dielectric resonator antenna (DRA) is presented and investigated. The proposed DRA is excited by a microstrip feed that is extended as a probe in the proximity of the DR. On the opposite side to the probe excitation printed narrow strips directly connected to the ground plane edge are used to improve the radiation characteristics of the antenna by keeping a unidirectional broadside radiation. In addition, the short circuit strips introduce a second frequency band. Thus, a dual‐band antenna is achieved. The measured bandwidths are about 73% (2.78–5.95 GHz) for the wideband DRA as well as 8% (2.4–2.6 GHz) and 56% (3.3–5.85 GHz) for the dual‐band DRA. The minimum and maximum gain enhancements of about 0.6 and 1.2 dB from 3.5 to 6 GHz are obtained. Parametric study and measurement results are presented and discussed. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1077–1081, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27492
Broadband Schiffman phase shifter using coupled suspended lines with tuning septums
Authors: Rhee Seungyeoup
Published: March 2013

A novel design of 90° Schiffman phase shifter using coupled suspended lines with tuning septums is presented for broadband operations.In this design, the 90° Schiffman phase shifter is realized with a high impedance ratio, which cannot be implemented using conventional coupled lines. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1036–1038, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27494
Planar monopole antenna for multiband wireless applications
Authors: Hosseini Seyed Ehsan , Attari Amir Reza , Majedi Mohammad Saeed
Published: March 2013

In this article, a new multiband planar monopole antenna for mobile devices application is presented. The proposed antenna operation is on the basis of using two radiation spiral strips and two slots on the ground plane. This antenna covers eight standard frequency bands including: GSM900, DCS1800, PCS1900, UMTS, WiBro, Bluetooth, WiMax, and WLAN. It occupies the area of 40 mm × 18 mm excluding the ground plane. A prototype of this antenna has been fabricated and its parameters have been measured. There is a good agreement between the measured and simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:966–970, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27497
High performance microstrip transverse resonance lowpass filter
Authors: Verma Anand K. , Chaudhari Nainu P. , Kumar Ashwani
Published: March 2013

We report 5‐pole Butterworth transverse resonance type lowpass filter (TR‐LPF) at cut‐off frequency 2.5 GHz with sharpness of cut‐off 170 dB/GHz, at 20 dB, 30 dB, 40 dB, and 50 dB rejection bandwidth of 9.2 GHz, 7.7 GHz, 5.9 GHz, and 3.12 GHz, respectively.The depth of attenuation is 68.7 dB. The parameters could be optimized for given specification. Such high order of attenuation is achieved by 30‐pole classical Hi–Lo LPF. The attenuation can be further increased to 72 dB for a 7‐pole LPF and 94 dB for a 11‐pole LPF. In case of the 11‐pole LPF at fc=2.5 GHz, we can achieve more that 7.1 GHz rejection bandwidth at 70 dB rejection. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1149–1152, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27501
Comparative study of numerical methods used in modeling of photonic crystal fibers
Authors: Díaz‐Soriano A. , Ortiz‐Mora A. , Dengra A.
Published: March 2013

In this article, we present a performance comparison, in terms of accuracy and computational cost, of the numerical techniques used in the resolution of the models of photonic crystal fibers.These models allow to obtain the electromagnetic field distributions and, once known this one, the dispersion parameter and the nonlinear coefficient. In this study, we conclude that the central finite difference scheme of fourth order would be the most advantageous. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1049–1053, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27504