bluuebunny/crossref_metadata_2025 huggingface dataset:
Technical Note: Impact of region of interest size and location in Gafchromic film dosimetry
Authors: Gholizadeh Sendani Neda , Karimian Alireza , Ferreira Clara , Alaei Parham
Published: March 2018

Purpose

To evaluate dependence of measured dose on size and location of region of interest (ROI) in Gafchromic EBT3 film dosimetry.

Methods

Gafchromic EBT3 films were irradiated perpendicularly using the 6MV beam from a linear accelerator at 10 cm depth (100 cm SSD) of a 30 × 30 × 20 cm3 solid water phantom for a range of field sizes of 6 × 6 to 100 × 100 mm2. ImageJ software was used for reading pieces of film. The appropriate location of ROIs in scanned films was found by two methods. First, the ROI was visually placed at the center of image. Second, the profile of pixel value versus distance was plotted and the center of profile was used for drawing ROI. Each scanned film was read using both methods and for three ROI sizes (1, 2, and 4 mm). A plastic scintillator, Exradin W1, was used as the reference dosimeter.

Results

Comparing the three ROI sizes using both methods showed that there was less than 2% difference from reference in output factor measurements for field sizes larger or equal to 10 × 10 mm2. The percentage differences were increased in field sizes smaller than 10 × 10 mm2 and for ROI size of 4 × 4 mm2 for both centered‐ROI and profiled‐ROI methods. The mean percentage differences from reference measurements, for field sizes of 100 × 100 to 20 × 20 mm2, were smaller than 1% in both methods of ROI positioning. For field sizes of 15 × 15 and 10 × 10 mm2, the smaller mean percentage differences were observed in profiled‐ROI (4 × 4 mm2) and centered‐ROI (4 × 4 mm2). For the field sizes of 8 × 8 and 6 × 6 mm2, the profiled‐ROI (2 × 2 mm2) had smallest mean percentage difference, which was 0.88%.

Conclusion

The ROI size of 4 × 4 mm2 is appropriate for dose measurements in field sizes of 100 × 100 mm2 to 10 × 10 mm2, regardless of the method of finding location of ROI. In field sizes smaller than 10 × 10 mm2, finding location of the ROI by profile of pixel values increases the accuracy of measurement, and ROI size of 2 × 2 mm2 has the smallest difference from the reference dose measurements.
Technical Note: Single time point dose estimate for exponential clearance
Authors: Madsen Mark T. , Menda Yusuf , O'Dorisio Thomas M. , O'Dorisio M. Sue
Published: March 2018

Objective

Although personalized dosimetry may be desirable for radionuclide therapy treatments, the multiple time samples required to determine the total integrated activity puts a burden on patients and clinic resources. The aim of this paper is to demonstrate that when some prior knowledge is known about the tracer kinetic parameters, the total integrated activity (and thus radiation dose) can be estimated from a single time sample.

Methods

Mathematical derivations have been performed to generate equations for the total integrated activity in terms of a single time sample of activity for monoexponential and biexponential clearance. Simulations were performed using both exponential models where the rate constants and associated parameters were randomly sampled from distributions with a known mean. The actual total integrated activity for each random sample was compared with the estimated total integrated activity using the mean value of the parameters. Retrospective analysis of 90Y DOTATOC data from a clinical trial provided a comparison of actual kidney dose with the estimated kidney dose using the single time point approach.

Results

The optimal sampling time for the single point approach was found to be equal to the mean time of the rate constant. The simulation results for the monoexponential and biexpoential models were similar. Regressions comparing the actual and estimated total integrated activity had very high correlations (r2 > 0.95) along with acceptable standard errors of estimate, especially at the optimal sampling point. The retrospective analysis of the 90Y DOTATOC data also yielded similar results with an r2 = 0.95 and a standard error of estimate of 61 cGy.

Conclusions

In situations where there is prior knowledge about the population averages of kinetic parameters, these results suggest that the single time point approach can be used to estimate the total integrated activity and dose with sufficient accuracy to manage radionuclide therapy. This will make personalized dosimetry much easier to perform and more available to the community.
Intensity modulated operating mode of the rotating gamma system
Authors: Sengupta Bishwambhar , Gulyas Laszlo , Medlin Donald , Koroknai Tibor , Takacs David , Filep Gyorgy , Panko Peter , Godo Bence , Hollo Tamas , Zheng Xiao Ran , Fedorcsak Imre , Dobai Jozsef , Bognar Laszlo , Takacs Endre
Published: March 2018

Purpose

The purpose of this work was to explore two novel operation modalities of the rotating gamma systems (RGS) that could expand its clinical application to lesions in close proximity to critical organs at risk (OAR).

Methods

The approach taken in this study consists of two components. First, a Geant4‐based Monte Carlo (MC) simulation toolkit is used to model the dosimetric properties of the RGS Vertex 360™ for the normal, intensity modulated radiosurgery (IMRS), and speed modulated radiosurgery (SMRS) operation modalities. Second, the RGS Vertex 360™ at the Rotating Gamma Institute in Debrecen, Hungary is used to collect experimental data for the normal and IMRS operation modes. An ion chamber is used to record measurements of the absolute dose. The dose profiles are measured using Gafchromic EBT3 films positioned within a spherical water equivalent phantom.

Results

A strong dosimetric agreement between the measured and simulated dose profiles and penumbra was found for both the normal and IMRS operation modes for all collimator sizes (4, 8, 14, and 18 mm diameter). The simulated falloff and maximum dose regions agree better with the experimental results for the 4 and 8 mm diameter collimators. Although the falloff regions align well in the 14 and 18 mm collimators, the maximum dose regions have a larger difference. For the IMRS operation mode, the simulated and experimental dose distributions are ellipsoidal, where the short axis aligns with the blocked angles. Similarly, the simulated dose distributions for the SMRS operation mode also adopt an ellipsoidal shape, where the short axis aligns with the angles where the orbital speed is highest. For both modalities, the dose distribution is highly constrained with a sharper penumbra along the short axes.

Conclusions

Dose modulation of the RGS can be achieved with the IMRS and SMRS modes. By providing a highly constrained dose distribution with a sharp penumbra, both modes could be clinically applicable for the treatment of lesions in close proximity to critical OARs.
Quantifying myofiber integrity using diffusion MRI and random permeable barrier modeling in skeletal muscle growth and Duchenne muscular dystrophy model in mice
Authors: Winters Kerryanne V. , Reynaud Olivier , Novikov Dmitry S. , Fieremans Els , Kim Sungheon Gene
Published: March 2018

Purpose

To measure the microstructural changes during skeletal muscle growth and progressive pathologies using the random permeable model with diffusion MRI, and compare findings to conventional imaging modalities such as three‐point Dixon and T2 imaging.

Methods

In vivo and ex vivo DTI experiments with multiple diffusion times (20‐700 ms) were completed on wild‐type (n = 22) and muscle‐dystrophic mdx mice (n = 8) at various developmental time points. The DTI data were analyzed with the random permeable model framework that provides estimates of the unrestricted diffusion coefficient (D0), membrane surface‐to‐volume ratio (S/V), and membrane permeability (κ). In addition, the MRI experiments included conventional measures, such as tissue fat fractions and T2 relaxation.

Results

During normal muscle growth between week 4 and week 13, the in vivo S/V, fractional anisotropy, and fat fraction correlated positively with age (ρ = 0.638, 0.664, and 0.686, respectively), whereas T2 correlated negatively (ρ = −0.847). In mdx mice, all DTI random permeable model parameters and fat fraction had significant positive correlation with age, whereas fractional anisotropy and T2 did not have significant correlation with age. Histological measurements of the perimeter‐to‐area ratio served as a proxy for the model‐derived S/V in the cylindrical myofiber geometry, and had a significant correlation with the ex vivo S/V (r = 0.71) as well as the in vivo S/V (r = 0.56).

Conclusion

The present study demonstrates that DTI at multiple diffusion times with the random permeable model analysis allows for noninvasively quantifying muscle fiber microstructural changes during both normal muscle growth and disease progression. Future studies can apply our technique to evaluate current and potential treatments to muscle myopathies.
Using Natural Marks to Identify Individual Cultured Adult Delta Smelt
Authors: Castillo Gonzalo C. , Sandford Marade E. , Hung Tien-Chieh , Tigan Galen , Lindberg Joan C. , Yang Wan-Ru , Van Nieuwenhuyse Erwin E.
Published: March 2018

Natural marks can provide a noninvasive approach to identify individual fishes, such as the endangered Delta Smelt Hypomesus transpacificus. We evaluated the feasibility of chromatophores as natural marks in cultured adult Delta Smelt and used the dorsal view of the head, where chromatophores are particularly abundant. Digital images of the head were compared among three photo sessions conducted at nearly 6-week intervals in winter–spring 2013 (n = 292–234). Images were evaluated visually (naked eye) and by automated image recognition (TinEye Application Programming Interface [API]). Visual analysis enabled us to correctly identify all 60 fish examined between each pair of photo sessions. The TinEye API also correctly identified 100% of the individuals when it was able to, but the software did not identify 6–41% of the fish between photo sessions; the longer the period between photo sessions, the lower was the percentage of fish identified by the TinEye API. Fish exposure to outdoor ambient light constricted chromatophores, but the percentage of image matching was not influenced by ambient light, gender, or spawning condition. We conclude that it is feasible to identify individual adult Delta Smelt throughout the spawning season without having to tag them, but further development of automated image recognition is needed.
Improved thermal and mechanical performance of ramie fibers reinforced poly(lactic acid) biocomposites via fiber surface modifications and composites thermal annealing
Authors: Debeli Dereje Kebebew , Tebyetekerwa Mike , Hao Jia , Jiao Fengshuang , Guo Jiansheng
Published: March 2018

Ramie fibers reinforced poly(lactic acid) (PLA) biocomposites in the recent past have gained a lot of research attention for various applications due to their biodegradability, lightweight and renewable advantages. However, their low thermal stability performances and poor mechanical properties have to this date limited their industrial use. Herein, an approach to solve the two mischiefs is presented, which involved first surface modifying of ramie fibers followed by thermal annealing of the reinforced PLA biocomposites. The resultant biocomposites showed tunable mechanical and thermal resistance properties. These improved properties are ascribed to the improved interfacial bonding of the modified ramie fibers and PLA polymer, courtesy of newly introduced reactive groups onto fibers which were capable of building strong interface bonds between the polymer–fiber boundaries. More still, the thermal stability of the resultant composite is attributed to the thermal annealing condition which provided crystallized PLA molecules upon exposure to high temperatures and the steady cooling responsible for the increased degree of crystallinity in the composites as confirmed from X‐ray diffraction and differential scanning calorimetric data results. Beyond ramie fibers‐based composites reported herein, the presented methodology can also be extended to other natural plant fiber‐based composites. These modifications are capable of providing better PLA/natural fiber‐based composites for automobiles, electronics, and other related domains. POLYM. COMPOS., 39:E1867–E1879, 2018. © 2018 Society of Plastics Engineers
Evaluation of spectral, thermal, flame retardant, dielectric, solvent diffusion, and transport behavior of novel nanocomposite derived from chlorinated styrene butadiene rubber and manganous tungstate
Authors: Jasna V.C. , Priyanka K. , Mathew G. , Ramesan M.T
Published: March 2018

Novel nanocomposites based on chlorinated styrene butadiene rubber (Cl‐SBR) and manganous tungstate (MnWO4) nanoparticles have been developed using a simple and efficient open two roll mixing mill at room temperature. The nanocomposite containing varying loading of nanoparticles have been assessed for their spectral behavior, thermal, dielectric, flammability properties as well as the transport of aromatic solvents through their networks. Intermolecular interaction between the chlorinated moieties of SBR and MnWO4 has been revealed by Fourier transform infrared and UV‐Vis spectral studies. The uniform dispersion of nanoparticles and the crystalline peaks of MnWO4 nanoparticles in Cl‐SBR were observed from SEM and XRD, respectively. Thermogravimetric analysis and flame resistance analysis showed that the thermal stability and flame retardancy of Cl‐SBR increased with increasing ratio of MnWO4. The dielectric constant was much improved with the entire range of frequencies and the optimum dielectric constant was obtained for 7 phr loading. Transport parameters like the sorption, diffusion, and permeation coefficients were tabulated in terms of the nature of solvent, and the loading of nanoparticles. The solvent uptake reduced by the addition of nanoparticles up to 7 phr and thereafter the solvent uptake increases. The activation energy for the diffusion, sorption, and permeation process was evaluated and these values were highest in xylene at all filler loading. The mechanism of transport of the aromatic solvents through Cl‐SBR/MnWO4 nanocomposite was found to be anomalous mode. POLYM. COMPOS., 39:E1880–E1889, 2018. © 2018 Society of Plastics Engineers
The influence of a magnetic field on the morphology and thermomechanical properties of a liquid crystalline epoxy carbon composite
Authors: Mossety‐Leszczak Beata , Kisiel Maciej , Szałański Piotr , Włodarska Magdalena , Szeluga Urszula , Pusz Sławomira
Published: March 2018

The synthesis of a novel ordered liquid crystalline epoxy carbon composite was presented in this article. Anthracite thermally modified at 2,000°C (SV2000) having graphitic structure was used as a filler in the composite with matrix obtained by crosslinking a liquid crystalline diepoxy monomer LCEM containing triaromatic mesogenic group. The curing agent was 4,4′‐diaminodiphenylmethane. The morphology and thermomechanical properties of the final products were characterized by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and wide angle X‐ray scattering (WAXS) analysis. It was found by WAXS measurements that alignment of LCEM was effectively induced in the matrix and in the composite filled with SV2000 by applying external magnetic field during cure. Thermosets with locked smectic C structure were obtained in all cases, with mesogenic fragments arranged along the applied field. The experimental results indicated that the presence of SV2000 as the filler of composite partially decreased the degree of order. The oriented composites exhibited anisotropy of the dynamic‐mechanical properties. POLYM. COMPOS., 39:E2573–E2583, 2018. © 2018 Society of Plastics Engineers
Proteins Identified from Saliva and Salivary Glands of the Chinese Gall Aphid Schlechtendalia chinensis
Authors: Yang Zixiang , Ma Lin , Francis Frederic , Yang Ying , Chen Hang , Wu Haixia , Chen Xiaoming
Published: March 2018

Aphid saliva plays an essential role in the interaction between aphids and their host plants. Several aphid salivary proteins have been identified but none from galling aphids. Here the salivary proteins from the Chinese gall aphid are analyzed, Schlechtendalia chinensis, via an LC‐MS/MS analysis. A total of 31 proteins are identified directly from saliva collected via an artificial diet, and 141 proteins are identified from extracts derived from dissected salivary glands. Among these identified proteins, 17 are found in both collected saliva and dissected salivary glands. In comparison with salivary proteins from ten other free‐living Hemipterans, the most striking feature of the salivary protein from S. chinensis is the existence of high proportion of proteins with binding activity, including DNA‐, protein‐, ATP‐, and iron‐binding proteins. These proteins maybe involved in gall formation. These results provide a framework for future research to elucidate the molecular basis for gall induction by galling aphids.
Synthetic Routes to Shaped AuPt Core–Shell Particles with Smooth Surfaces Based on Design Rules for Au Nanoparticle Growth
Authors: Stone Aidan L. , King Melissa E. , McDarby Sean P. , Robertson Daniel D. , Personick Michelle L.
Published: March 2018

Widespread implementation of polymer electrolyte fuel cells is limited by the performance of Pt catalysts because of the high cost of Pt and the propensity for catalyst surfaces to lose activity as a result of surface poisoning. AuPt core–shell particles show potential to address these issues, but offer new challenges because of the immiscibility of Au and Pt during particle growth. In this work, AuPt core–shell particles with distinct shapes are made using a one‐pot synthesis under mild reaction conditions by exploiting the difference in reduction rate between Au and Pt ions. Employing this approach results in smooth, well‐defined surfaces, rather than the more commonly observed dendritic or island‐like Pt shells that generally form when presynthesized Au cores are used to template Au‐core/Pt‐shell particle growth. By using the established mechanisms of Au nanoparticle growth, facile modification of particle shape and size is achieved with no significant change to the Pt surface. Consequently, this approach also offers a synthetic route to the preparation of more complex AuPt nanostructures, such as those with exotic shapes and high‐energy surface facets.
Point of care diaphragm ultrasound in infants with bronchiolitis: A prospective study
Authors: Buonsenso Danilo , Supino Maria C. , Giglioni Emanuele , Battaglia Massimo , Mesturino Alessia , Scateni Simona , Scialanga Barbara , Reale Antonino , Musolino Anna M.C.
Published: March 2018

Background

Bronchiolitis is the most common reason for hospitalization of children worldwide. Many scoring systems have been developed to quantify respiratory distress and predict outcome, but none of them have been validated. We hypothesized that the ultrasound evaluation of the diaphragm could quantify respiratory distress and therefore we correlated the ultrasound diaphragm parameters with outcome.

Methods

Prospective study of infants with bronchiolitis (1‐12 months) evaluated in a pediatric emergency department. Ultrasonography examinations of the diaphragm was performed (diaphragm excursion [DE], inspiratory excursion [IS], inspiratory/expiratory relationship [I/E], and thickness at end‐expiration [TEE] and at end‐inspiration [TEI]; thickening fraction [TF]).

Results

We evaluated 61 infants, 50.8 % males. Mean TF was 47% (IQR 28.6‐64.7), mean I/E 0.47 (± 0.15), mean DE 10.39 ± 4 mm. There was a linear correlation between TF and oxygen saturation at first evaluation (P = 0.006, r = 0.392). All children with lower values of TF required HFNC and one of them required CPAP. A higher IS was associated with the future need of respiratory support during admission (P = 0.007). IS correlated with the hours of oxygen delivery needed (P = 0.032, r = 0.422). TEI (t = 3.701, P = 0.002) was found to be main predictor of hours of oxygen delivery needed.

Conclusion

This study described ultrasound diaphragmatic values of previously healthy infants with bronchiolitis. DE, IS, and TEI correlated with outcome. If confirmed in larger studies, bedside ultrasound semiology of the diaphragm can be a new objective tool for the evaluation and outcome prediction of infants with bronchiolitis.
Diagnostic accuracy and therapeutic relevance of thoracoscopic lung biopsies in children
Authors: Fortmann Caroline , Schwerk Nicolaus , Wetzke Martin , Schukfeh Nagoud , Ure Benno M. , Dingemann Jens
Published: March 2018

Introduction

Histopathological assessment of lung biopsies does play an important diagnostic role in children's interstitial lung disease (ChILD). Thoracoscopic lung biopsy has been shown to be safe and effective. The aim of this study was to evaluate the diagnostic accuracy of thoracoscopic lung biopsies in children with ChILD. Furthermore, therapeutic relevance of the procedure, operative details, and perioperative complications of our series were investigated.

Methods

We retrospectively reviewed all consecutive thoracoscopic lung biopsies taken from children with suspected ChILD in our institution over an 11‐year period. Feasibility and complications were evaluated as well as histopathological diagnoses according to the recent ChILD classification and relevance of the procedure for medical treatment.

Results

Fifty‐nine patients (54.2% male, median age 7 years [8 d‐18 y]) underwent 112 thoracoscopic lung biopsies. An endostapler (27%), endoloop ligature (63%), or cut and suture technique (10%) were used. A chest tube was placed in 54% of the cases. Complications occurred in 15% of cases and mainly consisted of pneumothoraces or bleedings. Adequate tissue was obtained in all but one case and the biopsy led to a specific diagnosis according to the ChILD classification in 98%. Medical treatment of the underlying disease was changed due to the results of the biopsy in 86%.

Conclusions

The diagnostic accuracy of thoracoscopic lung biopsies in children with suspected ChILD is high. The histopathologic results lead to a disease‐specific treatment in the majority of the cases. Thoracoscopic lung biopsy is a safe and effective procedure with a low complication rate.
Ser‐486/491 phosphorylation and inhibition of AMPKα activity is positively associated with Gleason score, metastasis, and castration‐resistance in prostate cancer: A retrospective clinical study
Authors: Babcook Melissa A. , Akgul Mahmut , Margevicius Seunghee , MacLennan Gregory T. , Fu Pingfu , Abouassaly Robert , Gupta Sanjay
Published: March 2018

Background

We previously demonstrated that adenosine monophosphate‐activated protein kinase (AMPKα) activity is significantly inhibited by Ser‐486/491 phosphorylation in cell culture and in vivo models of metastatic and castration‐resistant prostate cancer, and hypothesized these findings may translate to clinical specimens.

Methods

In this retrospective, single‐institution pilot study, 45 metastatic prostate cancer cases were identified within the University Hospitals Cleveland Medical Center Pathology Archive with both metastasis and matched primary prostate tumor specimens in formalin‐fixed, paraffin‐embedded blocks, and complete electronic medical records. Thirty non‐metastatic, hormone‐dependent prostate cancer controls, who were progression‐free as defined by undetectable prostate specific antigen for at least 79.6 months (range 79.6‐136.0 months), and matched metastatic cases based on age, race, and year of diagnosis. All specimens were collected from 1991 to 2014; primary tumor specimens were obtained via diagnostic biopsy or prostatectomy, and metastasis specimens obtained via surgery or perimortem. 5‐μ sequential slides were processed for phospho‐Ser‐486/491 AMPKα1/α2, phospho‐Thr‐172 AMPKα, AMPKα1/α2, phospho‐Ser‐792 Raptor, phospho‐Ser‐79 acetyl‐CoA carboxylase, and phospho‐Ser‐872, 3‐hydroxy‐3‐methylglutaryl‐CoA reductase immunohistochemistry to determine expression, phosphorylation pattern, and activity of AMPKα.

Results

Increased inhibitory Ser‐486/491 AMPKα1/α2 phosphorylation, increased AMPKα protein expression, decreased AMPKα activity, and loss of nuclear AMPKα and p‐AMPKα are associated with prostate cancer progression to metastasis. Increased p‐Ser‐486/491 AMPKα1/α2 was also positively correlated with higher Gleason grade and progression to castration‐resistance.

Conclusions

p‐Ser‐486/491 AMPKα1/α2 is a novel marker of prostate cancer metastasis and castration‐resistance. Ser‐486/491 phosphokinases should be pursued as targets for metastatic and castration‐resistant prostate cancer chemotherapy.
Improving the Efficiency of AlGaN Deep‐UV LEDs by Using Highly Reflective Ni/Al p‐Type Electrodes
Authors: Maeda Noritoshi , Jo Masafumi , Hirayama Hideki
Published: March 2018

AlGaN‐based deep‐ultraviolet light‐emitting diodes (DUV LEDs) have a wide range of applications and a large market is expected. However, the efficiency of DUV LEDs is still much lower than that of blue LEDs due to the quite low light‐extraction efficiency (LEE). We are developing high LEE DUV LEDs by introducing a transparent contact layer and a highly reflective Ni/Al p‐type electrode. In this work, we investigate optimization of the Ni layer thickness of the highly reflective Ni/Al p‐type electrode for AlGaN DUV LEDs. We find that the reflectivity in the UV region becomes higher as the thickness of the Ni layer becomes smaller; however, the external quantum efficiency (EQE) is reduced if the Ni layer is too thin (<0.8 nm). As a result, we find that the most appropriate Ni thickness for the Ni/Al electrode is 0.9 nm. We fabricate 279 nm AlGaN quantum well (QW) DUV LEDs with the optimized electrodes and demonstrate an enhancement in EQE by a factor of 1.8 and a maximum EQE of 9% under bare wafer measurement conditions. We also demonstrate a high output power of 33 mW under an injection current of 100 mA.
Nano‐ and Micro‐Sized Fe2O3 Structures Fabricated by UV Imprint Lithography
Authors: Son Soomin , Jung Pil‐Hoon , Park Jaemin , Huh Daihong , Kim Kwan , Lee Hee‐Chul , Lee Heon
Published: March 2018

Iron oxide (Fe2O3), and especially hematite, is well known in photoelectrochemical applications such as water splitting and photocatalysis, and can also be used in solar energy conversion. Here, properties of iron oxide nanoparticles are investigated. The differences in the crystallization and refractive index of Fe2O3 nanoparticles, created under varied temperatures, are confirmed and analyzed in this paper. In addition, various nano‐ to microscale patterns of Fe2O3 nanoparticles enhance their features. UV imprint lithography, one of the simplest lithography procedures, is used to fabricate various iron oxide structures such as nanoholes, pillars, lines, microcones, and moth‐eyes on flexible or planar substrates. The optical properties of Fe2O3 patterns as fabricated are measured, and future applications are discussed.
Performances Enhancement of a‐Si:H Thin Film Photovoltaic Cells by Incorporating Silver Nanoparticles
Authors: Pokam Kuisseu Pauline S. , Yu Peiqing , Pingault Timothée , Blondeau Jean‐Philippe , Ntsoenzok Esidor , Andreazza Caroline , Roussel Julien , Mustapha Elyaakoubi , Meot Jacques , Jaffré Alexandre , Longeaud Christophe
Published: March 2018

a‐Si:H thin films‐based solar cells offer the benefit of reducing material consumption and fabrication costs. However, such thin absorbing layer reduces the photovoltaic efficiency, due to their poor light absorption at red and near‐infrared wavelengths. Metal NPs such as silver (Ag) can exhibit strong localized surface plasmon (LSP) resonances at different wavelength ranges, allowing increasing the light absorption in the active layer. The goal of this study is to perform an optimal structure of Ag NPs allowing to optimize the light absorption within the a‐Si:H solar cells by means of scattering. Ag layers are deposited on two different SnO2 substrates (with different roughness). After annealing, quasi‐spherical shaped of Ag NPs with diameters ranging from 10 to 130 nm are obtained. UV‐visible spectroscopy displays one LSP resonance around 560 nm with the less rough substrate, while three LSP resonances around 560, 700, and 850 nm are observed with roughest substrate. These differences are mainly due to the size distribution of NPs and underline the strong influence of the surface roughness and the coupling effect on the NPs behavior. a‐Si:H thin film solar cells with Ag NPs are subsequently elaborated. Spectral response shows an improvement of about 14–15%.
Switching Time in Ferroelectric Organic Field‐Effect Transistors
Authors: Sugano Ryo , Tashiro Tomoya , Sekine Tomohito , Matsui Hiroyuki , Kumaki Daisuke , Domingues Dos Santos Fabrice , Miyabo Atsushi , Tokito Shizuo
Published: March 2018

Ferroelectric organic field‐effect transistors (Fe‐OFETs) are considered a promising technology to develop flexible and low‐cost nonvolatile memories. Although their switching time between program‐state and erase‐state forms an important aspect of their functionality, it is still unclear as to what parameters dominate the switching time. Two possible parameters that influence the switching time are the channel formation of the semiconductor layer and the ferroelectric polarization in the ferroelectric layer. In this study, the origin of the switching time of the Fe‐OFETs is experimentally clarified. The switching times of Fe‐OFETs and ferroelectric capacitors are independently measured. Programming time of the Fe‐OFETs is limited by the above two times as expected; however, the ferroelectric polarization is not negligible and limited the time in most of cases. Additionally, it is found that switching time from depolarized erase‐state to polarized program‐state in the Fe‐OFETs is comparable to the ferroelectric polarization time in the ferroelectric capacitor. On the other hand, erasing time of the Fe‐OFETs is much slower than their programing time due to the depletion layer in the semiconductor layer. The erasing time can be predicted by taking a series capacitance made by depleted semiconductor layer into consideration.
Structural Stability, Electronic, and Optical Properties of BiVO4 With Oxygen Vacancy Under Pressure
Authors: Huang Yuhong , Yuan Yun , Ma Fei , Zhang Zongquan , Wei Xiumei , Zhu Gangqiang
Published: March 2018

In this paper, first‐principles calculations are performed to investigate the elastic constants, structural stability, electronic properties, and optical properties of ideal BiVO4 and BiVO4 with oxygen vacancy (Vo‐BiVO4) under equivalent hydrostatic and z‐axial pressure. It is found that the structural stability of the material is not affected and the indirect band‐gap is well kept in BiVO4 and Vo‐BiVO4, independent of the applied pressure. Essentially, as the equivalent hydrostatic and z‐axial pressure is increased, the hybridization of O 2p, V 3d, and Bi 6s orbitals will be enhanced in the ideal BiVO4, while the hybridization of O 2p, V 3d, and Bi 6p orbitals is enhanced in Vo‐BiVO4. Moreover, the band edges are shifted to lower energies under pressure, resulting in substantially reduced band gap, which might facilitate the photocatalytic performance. The shape of the optical spectrum of ideal BiVO4 displays an exponential form while that of Vo‐BiVO4 shows leaf‐like form in the low energy range, although they have similar shapes in the whole energy range. The absorption amount increases with the increase of z‐axial pressure, which might improve the visible light absorption.
Astragaloside IV reverses MNNG‐induced precancerous lesions of gastric carcinoma in rats: Regulation on glycolysis through miRNA‐34a/LDHA pathway
Authors: Zhang Chengzhe , Cai Tiantian , Zeng Xiaohui , Cai Dake , Chen Yuxing , Huang Xuejun , Gan Haining , Zhuo Juncheng , Zhao Ziming , Pan Huafeng , Li Siyi
Published: March 2018

This study was designed to investigate the precancerous lesions of gastric carcinoma (PLGC)‐reversing mechanisms of astragaloside IV (ASIV) in N‐methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG)‐induced PLGC rats. All rats were sacrificed after 10‐week treatment. Gastric tissue was analyzed by using histopathology and electron microscope. To be fully evidenced, LDHA, p53, TIGAR, MCT1, MCT4, HIF‐1α, CD147, and miRNA‐34a were detected by Western blotting and Real‐time Quantitative polymerase chain reaction (RT‐qPCR). As histopathology and electron microscope showed, it can be clearly observed that the area of dysplasia was reduced in ASIV groups, indicating that MNNG‐induced PLGC was markedly reversed by ASIV. Moreover, compared with model group, a significant decrease in gene expressions of LDHA, MCT1, MCT4, HIF‐1α, CD147, and TIGAR was observed whereas miRNA‐34a level was increased in ASIV groups. A significant up‐regulation induced by MNNG in protein levels of LDHA, MCT1, MCT4, HIF‐1α, and CD147 was attenuated in rats treated with ASIV. In contrast, the decreased expression of TIGAR was restored by ASIV. Interestingly, up‐regulation of p53 expression induced by MNNG was further increased in ASIV groups. In brief, these results implied that abnormal glycolysis was relieved by ASIV via regulation of the expressions of LDHA, p53, TIGAR, MCT1, MCT4, HIF‐1α, CD147, and miRNA‐34a.
Rapid and simultaneous quantification of a mixture of biopharmaceuticals by a liquid chromatography/quadrupole time‐of‐flight mass spectrometric method in rat plasma following cassette‐dosing
Authors: Park Min‐Ho , Byeon Jin‐Ju , Shin Seok‐Ho , Kim Nahye , Park Yuri , ill Lee Byeong , Choi Jangmi , Shin Young G.
Published: March 2018

Rationale

The cassette‐dosing technique is a technique that administers various drugs to a single animal at once and quantitated simultaneously. The purpose of this study was to evaluate the feasibility of cassette‐dosing as a means of increasing throughput and decreasing animal usage for pharmacokinetic studies of biopharmaceuticals using liquid chromatography/time‐of‐flight mass spectrometric (LC/TOF‐MS) analysis.

Methods

Brentuximab, trastuzumab, cetuximab and adalimumab were used as model biopharmaceuticals. The method consisted of immunoprecipitation followed by tryptic digestion for sample preparation and LC/TOF‐MS analysis of specific signature peptides in the positive ion mode using electrospray ionization. The specific signature peptides used for quantification were from the complementarity‐determining regions of each mAb. All rats received a single intravenous bolus injection containing either a single mAb or a mixture of four mAbs.

Results

The proposed method has been qualified in linearity range of 1–100 μg/mL with correlation coefficients higher than 0.990. The qualification run met the acceptance criteria of ±25% accuracy and precision values for quality control (QC) samples. This qualified LC/TOF‐MS method was successfully applied to a pharmacokinetic study in the rat. The PK properties of mAbs administered as a cassette‐dosage were similar to the pharmacokinetics of each antibody drug when administered as a single entity.

Conclusions

These findings suggest that the cassette‐dosing approach could be used to evaluate the PK properties of biopharmaceuticals in the early drug discovery stage. Also, this method would be useful for other preclinical sample analysis without developing new reagents for sample preparation.
Development of a new 3‐DOF parallel manipulator for minimally invasive surgery
Authors: Khalifa Alaa , Fanni Mohamed , Mohamed Abdelfatah M. , Miyashita Tomoyuki
Published: March 2018

This article proposes a novel dexterous endoscopic parallel manipulator for minimally invasive surgery. The proposed manipulator has 3 degrees of freedom (3‐DOF), which consist of two rotational DOFs and one translational DOF (2R1T DOFs). The manipulator consists of 3 limbs exhibiting identical kinematic structure. Each limb contains an active prismatic joint followed by 2 consecutive passive universal joints. The proposed manipulator has a unique arrangement of its joints' axes. This unique arrangement permits large bending angles, ±90° in any direction, and a workspace almost free from interior singularities. These advantages allow the proposed manipulator to outperforms existing surgical manipulators. However, this unique arrangement makes the analysis of the robot extremely difficult. Therefore, a geometrical/analytical approach is used to facilitate its singularity analysis. Construction of the virtual prototype is accomplished using ADAMS software to validate the proposed manipulator and its bending capability. A closed‐form solution for inverse kinematics is obtained analytically. Also, the forward kinematics solution is obtained numerically. Moreover, evaluation of the workspace is achieved using motion/force transmissibility indices. A practical experiment has been performed using a scaling technique and PID controller. The experimental results show the feasibility of the teleoperated surgical system using the proposed parallel manipulator as the slave.
Multivariate joint frailty model for the analysis of nonlinear tumor kinetics and dynamic predictions of death
Authors: Król Agnieszka , Tournigand Christophe , Michiels Stefan , Rondeau Virginie
Published: March 2018

The Response Evaluation Criteria in Solid Tumors are used as standard guidelines for the clinical evaluation of cancer treatments. The assessment is based on the anatomical tumor burden: change in size of target lesions and evolution of nontarget lesions (NTL). Despite unquestionable advantages of this standard tool, Response Evaluation Criteria in Solid Tumors are subject to some limitations such as categorization of continuous tumor size or negligence of its longitudinal trajectory. In particular, it is of interest to capture its nonlinear shape and model it simultaneously with recurrent progressions of NTL and overall survival. We propose a multivariate nonlinear mechanistic joint frailty model for longitudinal data, recurrent events, and a terminal event. In the model, the tumor size trajectory is described using an ordinary differential equation that accounts for the natural growth and treatment‐induced decline. We perform a simulation study to validate the method and apply the model to a phase III clinical trial in colorectal cancer. In the results of the analysis, we determine on which component, tumor size, NTL, or death the treatment acts mostly and perform dynamic predictions of death. We compare the model with other models that consider parametric functions or splines for the tumor size trajectory in terms of goodness of fit and predictive accuracy.
The sum of standardized residuals: Goodness‐of‐fit test for binary response models
Authors: Chen Lu , Sui Yihan , Song Chi , Rempala Grzegorz A.
Published: March 2018

We propose a new goodness‐of‐fit statistic for evaluating generalized linear models with binary responses on the basis of the sum of standardized residuals. We derive the asymptotic distribution of the sum of standardized residuals statistic and argue that, despite its relative simplicity, it typically outperforms many of the more sophisticated currently used goodness‐of‐fit statistics.
Comparing hierarchical models via the marginalized deviance information criterion
Authors: Quintero Adrian , Lesaffre Emmanuel
Published: March 2018

Hierarchical models are extensively used in pharmacokinetics and longitudinal studies. When the estimation is performed from a Bayesian approach, model comparison is often based on the deviance information criterion (DIC). In hierarchical models with latent variables, there are several versions of this statistic: the conditional DIC (cDIC) that incorporates the latent variables in the focus of the analysis and the marginalized DIC (mDIC) that integrates them out. Regardless of the asymptotic and coherency difficulties of cDIC, this alternative is usually used in Markov chain Monte Carlo (MCMC) methods for hierarchical models because of practical convenience. The mDIC criterion is more appropriate in most cases but requires integration of the likelihood, which is computationally demanding and not implemented in Bayesian software. Therefore, we consider a method to compute mDIC by generating replicate samples of the latent variables that need to be integrated out. This alternative can be easily conducted from the MCMC output of Bayesian packages and is widely applicable to hierarchical models in general. Additionally, we propose some approximations in order to reduce the computational complexity for large‐sample situations. The method is illustrated with simulated data sets and 2 medical studies, evidencing that cDIC may be misleading whilst mDIC appears pertinent.
Confined Assembly of Hollow Carbon Spheres in Carbonaceous Nanotube: A Spheres‐in‐Tube Carbon Nanostructure with Hierarchical Porosity for High‐Performance Supercapacitor
Authors: Chen Ze , Ye Sunjie , Evans Stephen D. , Ge Yuanhang , Zhu Zhifeng , Tu Yingfeng , Yang Xiaoming
Published: March 2018

Carbonaceous nanotubes (CTs) represent one of the most popular and effective carbon electrode materials for supercapacitors, but the electrochemistry performance of CTs is largely limited by their relatively low specific surface area, insufficient usage of intratube cavity, low content of heteroatom, and poor porosity. An emerging strategy for circumventing these issues is to design novel porous CT‐based nanostructures. Herein, a spheres‐in‐tube nanostructure with hierarchical porosity is successfully engineered, by encapsulating heteroatom‐doping hollow carbon spheres into one carbonaceous nanotube (HCSs@CT). This intriguing nanoarchitecture integrates the merits of large specific surface area, good porosity, and high content of heteroatoms, which synergistically facilitates the transportation and exchange of ions and electrons. Accordingly, the as‐prepared HCSs@CTs possess outstanding performances as electrode materials of supercapacitors, including superior capacitance to that of CTs, HCSs, and their mixtures, coupled with excellent cycling life, demonstrating great potential for applications in energy storage.
Toward High‐Performance Photodetectors Based on 2D Materials: Strategy on Methods
Authors: Yan Faguang , Wei Zhongming , Wei Xia , Lv Quanshan , Zhu Wenkai , Wang Kaiyou
Published: March 2018

Graphene and graphene‐like 2D layered materials such as black phosphorus, transition‐metal dichalcogenides, oxides, chalcogenides, and so forth have attracted tremendous attention due to their unique crystal structures, mechanical, and physical properties, as well as their variable bandgaps that range from 0 to 6 eV, which have offered their utilization in versatile devices. Using these materials as the active channel, many novel electrical and optoelectronic devices have been reported. Among the various important devices applications, photodetectors based on 2D materials have been extensively investigated with varied performance due to the different species and detection mechanisms. Here, the methods to improve the performance of 2D‐material‐based photodetectors are reviewed. There are five kinds of strategies regarding methods, including surface plasmon enhancement, charge‐transfer assistance, optical‐waveguide integration, graphene sandwiched structures, and heterostructures directly grown by CVD, which are developed and widely reported in recent years. For each method, the device design, performance, and mechanism are introduced and discussed systematically. Finally, a summary is provided to afford the principle to further enhance the performance of photodetectors based on 2D materials, with a perspective for their practical applications in the future.
The early record of halysitid tabulate corals, and morphometrics of Catenipora from the Ordovician of north‐central china
Authors: Liang Kun , Elias Robert J. , Lee Dong‐Jin
Published: March 2018

Catenipora is one of the most common tabulate coral genera in the Upper Ordovician Jinghe and Beiguoshan formations on the southern margin of the Ordos Basin, north‐central China. We distinguish and identify the species of Catenipora using multivariate morphometric procedures. Cluster analysis based on morphological characters of coralla yields a dendrogram showing five morphospecies. The validity and distinctiveness of the morphospecies are evaluated by discriminant analysis and non‐metric multidimensional scaling. To identify the species represented by the morphospecies, type specimens of species that are morphologically similar from north‐central China (Sino‐Korean Block) and surrounding palaeocontinents are compared with the morphospecies by non‐metric multidimensional scaling and descriptive statistics. The results indicate that one morphospecies represents C. daliangensis (Yu), another represents C. subovata Yu, and the others are new species herein named C. tongchuanensis, C. jingyangensis and C. tiewadianensis. Catenipora tongchuanensis from the middle of the Jinghe Formation (Sandbian; early Late Ordovician) is the earliest confirmed halysitid tabulate. Species of Catenipora in north‐central China (Sino‐Korean Block) show the highest morphological diversity (i.e. disparity) in terms of corallite size and shape, compared with other palaeocontinents in China. Species of Catenipora in North Qilian share more common components with those from north‐central China than any other palaeocontinent in China. The different morphological characteristics in terms of corallite shape and ranks in some Katian species of Catenipora from East Junggar, Mongolia, South China and Estonia suggest that some species may have originated separately during the Great Ordovician Biodiversification Event, and that Catenipora is possibly polyphyletic.
Analysis of Metabolomic Changes in Mesenchymal Stem Cells on Treatment with Desferrioxamine as a Hypoxia Mimetic Compared with Hypoxic Conditions
Authors: Fujisawa Koichi , Takami Taro , Okada Sae , Hara Kazusa , Matsumoto Toshihiko , Yamamoto Naoki , Yamasaki Takahiro , Sakaida Isao
Published: March 2018

Mesenchymal stem cells (MSCs) are commonly used in regenerative medicine, but their therapeutic effects vary depending on the culture environment. Hypoxic culturing can be used to maintain stem cells in an undifferentiated state, but is expensive and difficult to perform. The aim of this study was to determine the effectiveness of desferrioxamine (DFO), a hypoxia-mimetic reagent, as an alternative to hypoxic culturing by analyzing metabolic changes in MSCs under hypoxic conditions compared with changes induced by DFO. Low concentrations of DFO reduced mitochondrial activity and apoptosis. Therefore, low concentrations of DFO may be useful for MSC preconditioning. Metabolome analysis showed that both hypoxic treatment and DFO administration exhibited similar metabolite patterns except purine, pyrimidine, and tricarboxylic acid cycle (TCA) cycle related metabolites. Therefore, the use of DFO at low concentrations is a potential substitute for hypoxic culturing. These findings may form the foundation for the development of future regenerative therapies using MSCs.