bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of a rat lumbar IVD degeneration model for low back pain
Authors: Glaeser Juliane D. , Tawackoli Wafa , Ju Derek G. , Yang Jae H. , Kanim Linda EA , Salehi Khosrowdad , Yu Victoria , Saidara Evan , Vit Jean‐Phillipe , Khnkoyan Zhanna , NaPier Zachary , Stone Laura S. , Bae Hyun W. , Sheyn Dmitriy
Published: June 2020

Introduction

Intervertebral disc (IVD) degeneration is often associated with low back pain and radiating leg pain. The purpose of this study is to develop a reproducible and standardized preclinical model of painful lumbar IVD degeneration by evaluation of structural and behavioral changes in response to IVD injury with increasing needle sizes. This model can be used to develop new therapies for IVD degeneration.

Methods

Forty‐five female Sprague Dawley rats underwent anterior lumbar disc needle puncture at levels L4‐5 and L5‐6 under fluoroscopic guidance. Animals were randomly assigned to four different experimental groups: needle sizes of 18 Gauge (G), 21G, 23G, and sham control. To monitor the progression of IVD degeneration and pain, the following methods were employed: μMRI, qRT‐PCR, histology, and biobehavioral analysis.

Results

T1‐ and T2‐weighted μMRI analysis showed a correlation between the degree of IVD degeneration and needle diameter, with the most severe degeneration in the 18G group. mRNA expression of markers for IVD degeneration markers were dysregulated in the 18G and 21G groups, while pro‐nociceptive markers were increased in the 18G group only. Hematoxylin and Eosin (H&E) and Alcian Blue/Picrosirius Red staining confirmed the most pronounced IVD degeneration in the 18G group. Randall‐Selitto and von Frey tests showed increased hindpaw sensitivity in the 18G group.

Conclusion

Our findings demonstrate that anterior disc injury with an 18G needle creates severe IVD degeneration and mechanical hypersensitivity, while the 21G needle results in moderate degeneration with no increased pain sensitivity. Therefore, needle sizes should be selected depending on the desired phenotype for the pre‐clinical model.
A 2‐Phase Merge Filter Approach to Computer‐Aided Detection of Breast Tumors on 3‐Dimensional Ultrasound Imaging
Authors: Chiu Ling‐Ying , Kuo Wen‐Hung , Chen Chiung‐Nien , Chang King‐Jen , Chen Argon
Published: June 2020

Objectives

The role of image analysis in 3‐dimensional (3D) automated breast ultrasound (ABUS) images is increasingly important because of its widespread use as a screening tool in whole‐breast examinations. However, reviewing a large number of images acquired from ABUS is time‐consuming and sometimes error prone. The aim of this study, therefore, was to develop an efficient computer‐aided detection (CADe) algorithm to assist the review process.

Methods

The proposed CADe algorithm consisted of 4 major steps. First, initial tumor candidates were formed by extracting and merging hypoechoic square cells on 2‐dimensional (2D) transverse images. Second, a feature‐based classifier was then constructed using 2D features to filter out nontumor candidates. Third, the remaining 2D candidates were merged longitudinally into 3D masses. Finally, a 3D feature‐based classifier was used to further filter out nontumor masses to obtain the final detected masses. The proposed method was validated with 176 passes of breast images acquired by an Acuson S2000 automated breast volume scanner (Siemens Medical Solutions USA, Inc., Malvern, PA), including 44 normal passes and 132 abnormal passes containing 162 proven lesions (79 benign and 83 malignant).

Results

The proposed CADe system could achieve overall sensitivity of 100% and 90% with 6.71 and 5.14 false‐positives (FPs) per pass, respectively. Our results also showed that the average number of FPs per normal pass (7.16) was more than the number of FPs per abnormal pass (6.56) at 100% sensitivity.

Conclusions

The proposed CADe system has a great potential for becoming a good companion tool with ABUS imaging by ensuring high sensitivity with a relatively small number of FPs.
Response of Retinal Pigment Epithelium (RPE)‐Choroid Explants to Thermal Stimulation Therapy of the RPE (TSR)
Authors: Richert Elisabeth , Papenkort Julia , Klettner Alexa , Tode Jan , Koinzer Stefan , Brinkmann Ralf , Fink Christine , Roeder Thomas , Lucius Ralph , Roider Johann
Published: June 2020

Background and Objectives

The thermal stimulation therapy of the retinal pigment epithelium (TSR) is a sublethal laser technique for thermal stimulation of the retinal pigment epithelium (RPE)‐Bruch's membrane (BrM)‐complex. The aim of this study was to investigate the influence of TSR on the release of age‐related macular degeneration (AMD)‐relevant cell mediators.

Study Design/Materials and Methods

Porcine RPE‐BrM‐choroid explants were irradiated with a 532 nm continuous wave laser using different spot sizes (100–300 µm, duration 100 milliseconds, 15–100 mW). Cell death was investigated by calcein staining. Explants were treated with grids of sublethal spots and cultivated in modified Ussing chambers. The effect on matrix metalloproteinase‐2 (MMP‐2) and ‐9 was investigated by zymography and quantitative reverse transcription polymerase chain reaction. Secretion of vascular endothelial growth factor (VEGF), pigment epithelium derived factor (PEDF), and transforming growth factor‐β (TGF‐β) was analyzed by enzyme‐linked immunosorbent assay and expression of HSP70 was examined by western blot. Integrity of the RPE/BrM‐complex was analyzed by scanning electron microscopy.

Results

Laser powers of 15 mW (100 µm) and 45 mW (300 µm) did not induce RPE cell death. The integrity of the RPE/BrM‐complex was not impaired after TSR. After TSR with 300 µm spot size, we observed a significant increase of active MMP‐2 in the basal compartments. The content of PEDF significantly increased in treated explants in both compartments with 100 and 300 µm spot sizes. VEGF and TGF‐β secretion was not triggered by TSR.

Conclusions

TSR represents a possible RPE stimulating treatment for dry AMD. TSR increases the basal release of active MMP‐2, which might reverse age‐related thickening of BrM. VEGF secretion was not triggered by TSR while anti‐angiogenic PEDF was increased, indicating an induction of an anti‐angiogenic and neuroprotective environment. Lasers Surg. Med. © 2020 Wiley Periodicals LLC
A High Cell‐Bearing Capacity Multibore Hollow Fiber Device for Macroencapsulation of Islets of Langerhans
Authors: Skrzypek Katarzyna , Groot Nibbelink Milou , Liefers‐Visser Jolanda , Smink Alexandra M. , Stoimenou Eleftheria , Engelse Marten A. , de Koning Eelco J. P. , Karperien Marcel , de Vos Paul , van Apeldoorn Aart , Stamatialis Dimitrios
Published: June 2020

Macroencapsulation of islets of Langerhans is a promising strategy for transplantation of insulin‐producing cells in the absence of immunosuppression to treat type 1 diabetes. Hollow fiber membranes are of interest there because they offer a large surface‐to‐volume ratio and can potentially be retrieved or refilled. However, current available fibers have limitations in exchange of nutrients, oxygen, and delivery of insulin potentially impacting graft survival. Here, multibore hollow fibers for islets encapsulation are designed and tested. They consist of seven bores and are prepared using nondegradable polymers with high mechanical stability and low cell adhesion properties. Human islets encapsulated there have a glucose induced insulin response (GIIS) similar to nonencapsulated islets. During 7 d of cell culture in vitro, the GIIS increases with graded doses of islets demonstrating the suitability of the microenvironment for islet survival. Moreover, first implantation studies in mice demonstrate device material biocompatibility with minimal tissue responses. Besides, formation of new blood vessels close to the implanted device is observed, an important requirement for maintaining islet viability and fast exchange of glucose and insulin. The results indicate that the developed fibers have high islet bearing capacity and can potentially be applied for a clinically applicable bioartificial pancreas.
Aqueous RAFT Synthesis of Low Molecular Weight Anionic Polymers for Determination of Structure/Binding Interactions with Gliadin
Authors: Bristol Ashleigh N. , Carpenter Brooke P. , Davis Ashley N. , Kemp Lisa K. , Rangachari Vijayaraghavan , Karim Shahid , Morgan Sarah E.
Published: June 2020

Gliadin, a component of gluten and a known epitope, is implicated in celiac disease (CeD) and results in an inflammatory response in CeD patients when consumed. Acrylamide‐based polyelectrolytes are employed as models to determine the effect of molecular weight and pendent group on non‐covalent interaction modes with gliadin in vitro. Poly(sodium 2‐acrylamido‐2‐methylpropane sulfonate) and poly(sodium 3‐methylpropyl‐3‐butanoate) are synthesized via aqueous reversible addition fragmentation chain transfer (aRAFT) polymerization and characterized by gel permeation chromatography‐multiangle laser light scattering. The polymer/gliadin blends are examined via circular dichroism, zeta potential measurements, 8‐anilinonaphthalene‐1‐sulfonic acid fluorescence spectroscopy, and dynamic light scattering. Acrylamide polymers containing strong anionic pendent groups have a profound effect on gliadin secondary structure and solution behavior below the isoelectric point, while polymers containing hydrophobic character only have a minor impact. The polymers have little effect on gliadin secondary structure and solution behavior at the isoelectric point.
Tailoring the Self‐Healing Properties of Conducting Polymer Films
Authors: Li Yang , Zhang Shiming , Hamad Natalie , Kim Kyoungoh , Liu Leslie , Lerond Michael , Cicoira Fabio
Published: June 2020

The conducting polymer polyethylenedioxythiophene doped with polystyrene sulfonate (PEDOT:PSS) has received great attention in the field of wearable bioelectronics due to its tunable high electrical conductivity, air stability, ease of processability, biocompatibility, and recently discovered self‐healing ability. It has been observed that blending additives with PEDOT:PSS or post‐treatment permits the tailoring of intrinsic polymer properties, though their effects on the water‐enabled self‐healing property have not previously been established. Here, it is demonstrated that the water‐enabled healing behavior of conducting polymers is decreased by crosslinkers or by acid post‐treatment. Organic dopants of PEDOT have high water swelling ratios and lead to water‐enabled healing, while inorganic dopants fail in the healing of PEDOT. The water‐enabled healing of two isolated PEDOT:PSS squares with a 5 µm width gap and a thickness less than 1 µm is shown. This work will help pave the way for the further development of conducting polymer‐based self‐healable bioelectronics and flexible and stretchable electronics.
Singly generated quasivarieties and residuated structures
Authors: Moraschini Tommaso , Raftery James G. , Wannenburg Johann J.
Published: June 2020

A quasivariety of algebras has the joint embedding property (JEP) if and only if it is generated by a single algebra A. It is structurally complete if and only if the free ℵ0‐generated algebra in can serve as A. A consequence of this demand, called ‘passive structural completeness’ (PSC), is that the nontrivial members of all satisfy the same existential positive sentences. We prove that if is PSC then it still has the JEP, and if it has the JEP and its nontrivial members lack trivial subalgebras, then its relatively simple members all belong to the universal class generated by one of them. Under these conditions, if is relatively semisimple then it is generated by one ‐simple algebra. We also prove that a quasivariety of finite type, with a finite nontrivial member, is PSC if and only if its nontrivial members have a common retract. The theory is then applied to the variety of De Morgan monoids, where we isolate the sub(quasi)varieties that are PSC and those that have the JEP, while throwing fresh light on those that are structurally complete. The results illuminate the extension lattices of intuitionistic and relevance logics.
Parallel and totally geodesic hypersurfaces of non‐reductive homogeneous four‐manifolds
Authors: Calvaruso Giovanni , Storm Reinier , Van der Veken Joeri
Published: June 2020

We classify totally geodesic and parallel hypersurfaces of four‐dimensional non‐reductive homogeneous pseudo‐Riemannian manifolds.
Multiple Hydrogen Bonds–Reinforced Hydrogels with High Strength, Shape Memory, and Adsorption Anti‐Inflammatory Molecules
Authors: Li Xuefeng , Peng Xueyin , Li Rongzhe , Zhang Yikun , Liu Zuifang , Huang Yiwan , Long Shijun , Li Haiyan
Published: June 2020

The research on multiple hydrogen bonds (H‐bonds) hydrogels have gradually aroused wide interest. In this paper, a multiple H‐bonds‐reinforced poly(acrylamide‐co‐2‐vinyl‐4,6‐diamino‐2‐vinyl‐1,3,5‐triazine)/tannic acid (P(Am‐co‐VDT)/TA) hydrogels are prepared. The results suggest that the prepared hydrogel has two types of H‐bonds crosslinking regions: A “soft” region of H‐bonds between the diaminotriazine (DAT) moieties on the polymer chains and the TA pyrogallol/catechol groups, and a “hard” region of H‐bonds forming by DAT moieties with itself. The hard crosslinking region exhibits significantly higher activation energy than the soft region. Such soft and hard dual physically crosslinked networks dramatically enhance the mechanical properties of P(Am‐co‐VDT)/TA hydrogels in a synergistic manner (tensile strength is 2.34 MPa, elongation at break is 410%). Due to the multiple hydrogen bonds, the hydrogel has good pH sensitivity and rapid response to shape memory within a few minutes. In addition, the hydrogels have the capacity of physical adsorption of the anti‐inflammatory drug diclofenac sodium and other molecules with a specific spatially arranged chemical composition. These hydrogels with high mechanical strength, excellent shape memory behavior, and capacity of adsorption of anti‐inflammatory drug could be attractive candidates for applications in the fields of biomedicine, tissue engineering, and medical materials.
Stability of Anthocyanins Encapsulated from Purple Sweet Potato Extract Affected by Maltodextrin Concentration
Authors: Arisanti Cokorda Istri Sri , Sukawati Cokorda B. Arys Cahaya , Prasetia I Gusti Ngurah Jemmy Anton , Wirasuta I Made Agus Gelgel
Published: June 2020

Microencapsulation is a method for protecting anthocyanin from degradation and external environment. This study aims to characterize microcapsules prepared from purple sweet potato (Ipomoea batatas L.) extract. In this research, the effect of maltodextrin (MD, DE 10–15) concentration as a wall material on the physicochemical properties of microwave‐assisted, encapsulated purple sweet potato extract (PSPE) is investigated. Organoleptic, moisture content, particle size, particle size distribution, encapsulation efficiency, and total anthocyanin content (TAC) are evaluated for microcapsules. The stability of the microencapsulated product is determined on different pH (3, 5, and 7) and temperature (35, 75, and 115 °C) for 21 and 5 days. The result shows that moisture content, particle size, TAC, and encapsulation efficiency of the microcapsules are significantly increased (p < 0.01) as the MD concentration increases. Microcapsules produced with highest maltodextrin concentration exhibits higher stability on the pH 7 at 115 °C than others. Maltodextrin DE 10–15, in high concentration increases the stability of anthocyanin from PSPE.
Characterization of Migration Rate and Biodegradability of Cassava Starch‐Based Biofoam Modified with Alkyl Ketene Dimer
Authors: Wahyuningsih Kendri , Iriani Evi Savitri , Yuanita Evana
Published: June 2020

Modification of starch‐based foam packaging using chemicals as additives or sizing agent may cause the chemical compounds to migrate and affect the biodegradability. This study aims to determine the characteristics of migration and biodegradability of cassava starch‐based biofoam modified with alkyl ketene dimer (AKD). Thermopressing techniques from mixtured cassava starch with oil palm empty fruit bunches pulp, polyvinyl alcohol, magnesium stearate, water, and AKD as the sizing agent are used in the method of making biofoam. From the result of experiment it is found that cassava starch‐based biofoam has a migration rate far higher than the permitted threshold for food packaging materials. That is because the properties of cassava starch‐based biofoam cannot be approached by those of polystyrene‐based packaging. Therefore, further research is needed to determine the type of simulants suitable for migration testing of cassava starch‐based biofoam. However, biofoam is safe from heavy metals and is biodegradable after 21 days so that it can be used as an alternative for packaging food with low water content (dry foods).
Biodegradable Microcapsules from D,L–PLA/PCL as Controlled Nifedipine Drug Delivery Carrier
Authors: Astuti Suci Hepy , Rahma Wanda Amelia , Budianto Emil
Published: June 2020

In this study, microcapsules are prepared as a controlled drug Nifedipine delivery carrier. Nifedipine is a calcium channel blocker, it is widely used in the treatment of angina pectoris and hypertension. The microcapsules are prepared using o/w emulsification method. The core materials of microcapsules are polyblend of D,L‐poly(lactic acid) (PLA) and poly(ɛ‐caprolactone) (PCL) using Span 80 and Tween 80 as an emulsifier. D,L‐PLA, and PCL are dissolved into dichloromethane then emulsified and dispersed into water to form microcapsules. The sizes, uniformity of microcapsules, and the ability to encapsulate the drug are influenced by the composition of D,L‐PLA, and PCL. This study observes the appearance, ability to encapsulate the drug, and the dissolution at the various compositions ratio of D,L‐PLA:PCL. The blend of D,L‐PLA, and PCL is only formed through physical interaction between them. The surface texture of microcapsules is observed by optical microscope. It obtains that the composition of D,L‐PLA (80):PCL (20) shows the best ability to encapsulate the drug with evidently obtaining the highest encapsulation efficiency by 86.58%. The best microcapsule dissolution test results in drug release of 24.01% within 55 h.
Addition of Hybrid Coupling Agent Based Natural Rubber‐Starch on Natural Rubber Composite
Authors: Roziafanto Achmad Nandang , Puspitasari Sinta , Cifriadi Adi , Hasnasoraya Dinda , Chalid Mochamad
Published: June 2020

Natural rubber blended with biomass fibers as a filler is one of promising methods to produce high‐quality car tire that require good thermal resistance and low noise level caused by the frictional forces between the tire and road. Biomass fibers have suitable acoustic properties, good tensile strength, and also density regarding its chain molecule structure and porous structure. The major biomass byproduct from the palm oil industry in Indonesia is empty fruit bunches (EFBs). Because of the different polarity of natural rubber and EFBs, coupling agent has to be added for producing composite with good miscibility and desired mechanical properties. In this study the hybrid coupling agent based natural rubber‐starch prepared with glow discharge electrolysis plasma method is added to the natural rubber/EFBs fibers composite. The ratio of EFBs fibers to the composite is varied to 5, 10, and 15 phr, while the coupling agent is added at fixed 1 phr. Field emission scanning electron microscopy (SEM) and mechanical testing are used for the composite characterization. The mechanical tests showed that the addition of coupling agents provides greater tensile strength compared to composites without the addition of coupling agent. These results are supported by morphology analyses using SEM, showing the good interaction on the surface between the EFBs fibers and the natural rubber matrix with addition of the coupling agent.
Preliminary Study of Modified Lignin Compatibility in Polypropylene‐Modified Bitumen
Authors: Roziafanto Achmad Nandang , Alfarisi F. H. , Ramadhan T. H. , Chalid Mochamad
Published: June 2020

Lignin is an amorphous biopolymer that has both polar and nonpolar characteristics which has been proven able to chemically bond bitumen and polypropylene. However, the presence of polar bond in lignin is more dominant than the nonpolar one making it less effective to bond polypropylene. Thus, lignin is modified to reduce its polar hydroxyl group by synthetizing it with prepolyurethane otherwise known as polyurethanization. This modified lignin compatibility to bond bitumen and polypropylene is then studied and compared with lignin, such is the true purpose of this research. Experiment is done through several stages ranging from sample preparation, mixing, and characterization. Hot melt mixing method is used to mix bitumen, polypropylene, and modified lignin with mass ratio of 19:1 for bitumen and polypropylene, which are mixed in 80 rpm. Mixing is done at the temperature of 180 °C for 30 min with 0.3% total weight addition of modified lignin. Characterizations are done using FT‐IR and FESEM. Result shows that modified lignin has better compatibility compared to pure lignin.
Glucomannan–Beeswax–Chitosan Antimicrobial Edible Coating to Maintain the Storage Quality of Salak Fruit (Salacca zalacca)
Authors: Meindrawan Bayu , Ofe Ofe , Susanto Clarissa Sarah , Ayman Azzadin , Mangindaan Dave , Kasih Tota Pirdo
Published: June 2020

In this study, the possibility to improve the quality and shelf life of salak (snake fruit, Salacca zalacca) via application of glucomannan–beeswax–chitosan polymer edible film coating is investigated. The formulated glucomannan–beeswax–chitosan edible coating is applied to minimally processed salak, and the characteristics of the edible coating are evaluated. The glucomannan–beeswax–chitosan edible coating not just successfully reduces the growth of Staphylococcus aureus and Escherichia coli (10%, compared to control, that is, the salak fruit coated with glucomannan only), but also decreases the water vapor transfer rate that penetrates salak fruit (by 27% vs control), and lowers the weight loss of salak fruit (<4%, compared to that of control (10% weight loss)). Peeled salak fruit coated with glucomannan–beeswax–chitosan maintains its quality at room temperature in 3 days, without any indication of mold growth. Based on the results in this study, glucomannan–beeswax–chitosan edible coating is a promising antimicrobial edible polymer coating for minimally processed salak fruit, and possibly for other varieties of fruits.
Effect of Carbon Black/Bi2O3 Ratio on the Vulcanization Characteristic and Mechanical Properties of Rubber Compound
Authors: Nurhajati Dwi W. , Lestari Umi R. , Setyorini Ike , Mayasari Hesty E.
Published: June 2020

This study aims to determine the effect of Bi2O3 as a substitute for carbon black (CB) fillers on the characteristics of vulcanization and mechanical properties of rubber compounds. The comparison of CB/Bi2O3 used are 50/0, 45/5, 40/10, and 35/15. Rubber compounds are prepared using two‐rolls mill. The rubber vulcanizates are prepared using hydraulic press at 150 °C. Vulcanization characteristics are determined by the moving die rheometer. Rubber vulcanizates are evaluated from aspects of physical and mechanical properties (tensile strength, elongation, density, hardness), morphology (SEM), and heat aging. It is found that rubber compounds containing high amounts of Bi2O3 show higher torque and higher optimum vulcanization time. In addition, rubber compounds with high Bi2O3 content show higher density, tensile strength, and elongation.
Mastication Process of Natural Rubber/Butadiene Rubber Blending: Validation Method on Influence of Peptizer
Authors: Arti Dewi K. , Hidayat Ade S. , Ulfah Ika M. , Susanto Herri , Wisojodharmo Lies A. , Dandi Ahmad
Published: June 2020

The performance of tire tread is measured by the combination of “magic triangle properties.” They are rolling resistance, traction, and wear. To obtain high quality of tire tread, good quality of rubber compound is necessary to be prepared. Natural rubber (NR) has a wide application especially in tire tread. Cured Butadiene Rubber (BR) impacts excellent abrasion resistance and low rolling resistance due to its low glass transition temperature (Tg). Mastication process is a very important step in compounding preparation. To obtain homogeneous compounding, mastication has to be prepared well. Recently, the effect of peptizer in the mastication process of natural rubber/butadiene rubber has been investigated by using Vestenamer, Aktiplast 8, and Rhenosin 145. To validate to method and formulation, the experiment is repeated three times to find out the type of peptizer that provide the highest compatibility to masticate natural rubber and butadiene rubber as well. The experimental design is done to collect the data and repeatability of each peptizer effect is analyzed by calculating the variance (ANOVA test). As expected, the addition of Vestenamer significantly increases the mechanical properties, and it has better repeatability than others. However, the value of tensile strength and tear strength are still lower than Aktiplast, but it has already fulfilled the requirement, 20 N/mm2 and 200 N, for tensile strength and tear strength, respectively. It is proved that Vestenamer can optimize the mastication process.
Optimization of Fiber Content and Alkali Treatment on Sound Damping Performances of Kenaf Core/Unsaturated Polyester Composites
Authors: Vicarneltor David Natanael , Ujianto Onny , Setijotomo Hendro Sat , Nurindah
Published: June 2020

Kenaf core/unsaturated polyester (KC/UP) composites are prepared by mechanical stirrer followed by compression molding. Effect of fiber percentage as well as alkali treatment (NaOH concentration and immersion time) on sound damping performance are analyzed and optimized using three factors and three levels of Box–Behnken experimental design. Flexural properties, heat deflection temperature (HDT), density, lignin content, and morphology are investigated on selected samples. The results show that the optimum condition to produce KC/UP composites is predicted at 54.5% of fiber, 8.1% of NaOH used on alkali treatment, and 2 h fiber immersion on NaOH, giving 5.6% of sound damping/mm. Verifying the model results in 5.1% of sound damping/mm. Despite lower value of verification sample than predicted, this is still between 95% of predicting interval (4.1–7.1%), which is still higher than control sample (3.8%), suggesting model capability to predict the result. Further analysis on selected samples with the highest, mid and lowest sound damping property results in the change of flexural modulus at 38%, −9%, and 28%, respectively, and improvement in HDT (23%, 12%, and 22%). However, the flexural strengths of all selected samples are lower than that of control (−37%, −67%, and −44%). Morphology analysis shows that sample with 45% fiber content is more compact than 30% fiber content, which improves sound damping.
The Crystallinity of Arenga pinnata “Ijuk” Fiber Cellulose through KMnO4 Addition on NaClO Bleaching Process
Authors: Yuanita Evana , Pudjiastuti Wiwik , Chalid Mochamad
Published: June 2020

Arenga pinnata “ijuk” fiber is one of the lignocellulosic sources that is abundant in Indonesia. At present, this fiber is only for brush, shiever, mat, and rope. Delignified “ijuk” fiber is a potential source of cheap crystalline cellulose, a material that can be used for composite. This paper presents chemical treatment of A. pinnata “ijuk” fiber to get cellulose with high crystallinity. The fiber is treated by alkalization with 2% sodium hydroxide (NaOH) for 1 h, 0.01 n KMnO4 as NaClO activator for 10 min and bleaching with 5% NaClO at varying time of treatment 3, 5, 7 h, respectively. For comparison, the fiber is treated with 2% sodium hydroxide (NaOH) for 1 h and then with 5% NaClO without KMnO4 for 3 h (N3). Addition of KMnO4 as NaClO activator will control ClO gas released and then the bleaching process becomes more effective because the ClO gas will bleach the fiber, not releasing fast to the air. Furthermore, NaClO leads an oxidative fragmentation from the remaining lignin and then the lignin dissolves out from the fiber. The result shows that the highest crystallinity of the cellulose is the fiber which is treated by alkalization with 2% sodium hydroxide (NaOH) for 1 h, 0.01 n KMnO4 for 10 min, and oxidation with 5% NaClO for 5 h (KN5). Fourier transform infrared confirms the removal of some lignocellulosic components such as lignin, wax, and hemicelluloses; X‐ray diffraction reveals an increase of crystalline parts in the fiber via cellulose through crystallinity index value. Field emission scanning electron microscopy displays dimension and surface morphology of fiber. So the treatment can remove some amorphous part of the lignocellulose namely, lignin and hemicellulose to obtain cellulose with high crystallinity.
Three solutions for a class of fractional impulsive advection‐dispersion equations with Sturm‐Liouville boundary conditions via variational approach
Authors: Min Dandan , Chen Fangqi
Published: June 2020

In this paper, the Sturm‐Liouville problem is studied for fractional advection‐dispersion equations with impulsive effects. The existence of multiple solutions is obtained by making use of three critical points theorem. An example is given as an application of our main results.
Quantification of internal dosimetry in PET patients: individualized Monte Carlo vs generic phantom‐based calculations
Authors: Neira Sara , Guiu‐Souto Jacobo , Díaz‐Botana Pablo , Pais Paulino , Fernández Carlos , Pubul Virginia , Ruibal Álvaro , Candela‐Juan Cristian , Gago‐Arias Araceli , Pombar Miguel , Pardo‐Montero Juan
Published: June 2020

Purpose

The purpose of this work is to calculate individualized dose distributions in patients undergoing 18F‐FDG PET/CT studies through a methodology based on full Monte Carlo (MC) simulations and PET/CT patient images, and to compare such values with those obtained by employing nonindividualized phantom‐based methods.

Methods

We developed a MC‐based methodology for individualized internal dose calculations, which relies on CT images (for organ segmentation and dose deposition), PET images (for organ segmentation and distributions of activities), and a biokinetic model (which works with information provided by PET and CT images) to obtain cumulated activities. The software vGATE version 8.1. was employed to carry out the Monte Carlo calculations. We also calculated deposited doses with nonindividualized phantom‐based methods (Cristy–Eckerman, Stabin, and ICRP‐133).

Results

Median MC‐calculated dose/activity values are within 0.01–0.03 mGy/MBq for most organs, with higher doses delivered especially to the bladder wall, major vessels, and brain (medians of 0.058, 0.060, 0.066 mGy/MBq, respectively). Comparison with values obtained with nonindividualized phantom‐based methods has shown important differences in many cases (ranging from −80% to + 260%). These differences are significant (p < 0.05) for several organs/tissues, namely, remaining tissues, adrenals, bladder wall, bones, upper large intestine, heart, pancreas, skin, and stomach wall.

Conclusions

The methodology presented in this work is a viable and useful method to calculate internal dose distributions in patients undergoing medical procedures involving radiopharmaceuticals, individually, with higher accuracy than phantom‐based methods, fulfilling the guidelines provided by the European Council directive 2013/59/Euratom.
Letter regarding “Early electrodiagnosis in the management of neonatal brachial plexus palsy: A systematic review”
Authors: Rehm Andreas , Thahir Azeem
Published: June 2020

See article on pages E72–E73 in this issue.
The effect of adding online homework assignments to a small introductory physical geology class
Authors: Brevik Eric C.
Published: June 2020

Online homework (OLH) assignments were added to the Introduction to Physical Geology class at Dickinson State University in the fall semester of 2014. Anticipated advantages included timely feedback and opportunities for students to correct mistakes made during homework completion. The same instructor taught all lecture and laboratory sections over the course of the study, and student performance was compared for the 3 years prior to adopting the OLH and the 3 years after. Following adoption of the OLH, the average grade in the class increased by 7.5% and average test scores increased by 6.2%. The OLH did not significantly improve the performance of the top students (those who received an A), but it did improve the performance of the other students. Test grades showed a similar trend. The average test scores for those who received an A in the class were 88.0% before and 88.6% after adopting the OLH, whereas test averages for students who received less than an A were 63.9% before and 71.4% (7.5% improvement) after adopting the OLH. There was no statistical difference in scores in the Introduction to Physical Geology laboratory over the same period. Students are required to take the lecture and laboratory at the same time, so the student populations were virtually identical. The OLH applied to the lecture, where grades improved, but not to the laboratory, where grades remained consistent. Therefore, it was concluded that the OLH improved student performance.
Fabrication of polystyrene/carbon nanocomposites with superior mechanical properties
Authors: Yeh Shu‐Kai , Su Chi‐Chun , Huang Jian‐Ming , Ke Ming‐Qing , Bogale Dawit , Anbarasan Ramasamy , Tung Kuo‐Lun , Wang Sea‐Fue
Published: June 2020

Adding fillers reinforces the modulus of the polymer, but the ductility is sacrificed. Such a phenomenon is especially true for brittle polymers like polystyrene (PS). Nanofillers are known to solve the problem because the high aspect ratio and surface area may improve the stiffness at a much lower loading level, and thus significantly reduce the ductility. However, the dispersion of nanofillers is always challenging. In the current investigation, PS nanocomposites were prepared by melt compounding, ultrasonication, and solution compounding to investigate the effect of the addition of the following carbon nanomaterial to the mechanical properties: nanographite (H25), multiwalled carbon nanotube, carbon nanofiber, and thermally reduced graphene (TRG). Among them, TRG exhibited the best reinforcing effect. Young's modulus of PS increased by 27% with only 0.1 wt% loading of TRG, and the ductility remained unchanged. Such an improvement has rarely been reported in thermoplastic polymer nanocomposites. The results were carefully analyzed and compared with those reported in the available literature. In this study, the solution compounding method offered the best modulus value. The aspect ratio of carbon nanomaterials in the composite was estimated by the Halpin‐Tsai equation. These estimations agree well with the transmission electron microscopy microstructure results.
High‐performance HTL‐free perovskite solar cell: An efficient composition of ZnO NRs, RGO, and CuInS2 QDs, as electron‐transporting layer matrix
Authors: Taheri‐Ledari Reza , Valadi Kobra , Maleki Ali
Published: June 2020

A hole‐transporting layer (HTL)‐free perovskite solar cell (PSC) with fluorine‐doped tin oxide (FTO)/nanocomposite electron‐transporting layer (ETL)/perovskite/Au structure is presented that takes advantage of a novel ternary nanocomposite constructed of zinc oxide (ZnO) nanorods, reduced graphene oxide (RGO), and copper indium sulfide quantum dots (CuInS2 QDs), as ETL. Concisely, the photoelectric and photovoltaic properties of all the individual, binary, and ternary composites were monitored by using of the photoluminescence (PL) spectroscopy, UV‐visible (vis) spectroscopy, J‐V curves, and incident photon‐to‐current conversion efficiency (IPCE) spectra studies. The comparative values exhibited a noticeable benefit for the ZnO‐RGO5%‐CuInS220% ternary nanocomposite as an appropriate ETL for PCS. Also, the comparative structural studies on the individual nanoscale components, binary, and ternary nanocomposite (with different percentages of CuInS2 QDs) were precisely performed by Fourier transform infrared (FT‐IR), energy‐dispersive X‐ray (EDX), X‐ray diffraction (XRD), Raman spectroscopy, and field emission scanning electron microscopy (FESEM), as well. Overall, after careful optimization of the ETL, a15.74% efficiency was resulted through applying the prepared ZnO‐RGO5%‐CuInS220% composite in a HTL‐free PCS with 0.33 cm2 active area.
Rock glaciers automatic mapping using optical imagery and convolutional neural networks
Authors: Marcer Marco
Published: June 2020

Despite their relevance in alpine environments, rock glaciers remain uncharted in several regions of the globe due to the considerable efforts required in the mapping process. To develop a support tool for rock glacier mapping, this study investigates the feasibility using artificial intelligence to recognize these landforms on satellite optical imagery. The results of this exploratory analysis indicate that convolutional neural networks can accurately classify unshadowed and snow‐free rock glaciers images (88% true positives and 79% true negatives on the test set). A simple detection algorithm is also tested, achieving inferior, but still promising, performances. The algorithm works on large orthoimages and is capable of spotting large rock glaciers characterized by a ridge–furrow structure, although the detection results in several false positives. Overall, the results suggest that further developments of this methodology can produce useful tools to facilitate efforts in mapping rock glaciers for large uncharted regions.
Comparative analysis of dose verification between computed tomography scan phantom and virtual digital phantom of Delta4
Authors: Liu Ting‐Ting , Dai Zhi‐Tao , Kang Kai‐Lian , Gao Li‐Ying , Liu Rui‐Feng , Ou‐Yang Shui‐Gen
Published: June 2020

Objective

This study compared the dose verification results between plans created based on computed tomography (CT) scan and digital virtual phantom.

Methods

We retrospectively analyzed the treatment plan of 10 patients with head and neck cancer. CT scanned phantom and digital virtual phantom measured using Delta4 3‐D matrix were used to generate verification plans for each patient. The doses based on the effective measurement volume of the two phantoms were compared, and the verification results were analyzed using gamma index analysis.

Results

For the body, the minimum dose, the maximum dose, the average dose, and the total dose were 0.72 ± 0.46 cGy, 251.86 ± 49.83 cGy, 58.10 ± 10.93 cGy, and 154.67 ± 20.28 cGy, respectively, in the CT‐scan group, and 0.62 ± 0.36 cGy, 248.34 ± 48.59 cGy, 57.20 ± 10.77 cGy, and 151.57 ± 19.73 cGy, respectively in the Uniform group. The difference between the groups was significant (P < 0.05). In the Delta4 analysis software, the dose deviation, distance to agreement, and gamma passing rates were 73.39 ± 10.75%, 95.25 ± 1.00%, and 96.67 ± 1.415%, respectively in the CT‐scan group, and 83.36 ± 10.15%, 98.61 ± 0.810%, and 99.38 ± 0.452%, respectively, in the Uniform group. The two plans were significantly different (P < 0.05), and there was a 3% difference in the gamma passing rate. Therefore, the conclusions relating to the examined dose applied, the groups were significantly higher than those of CT‐scan groups. (both P‐values were <0.05). As the parameter value increases, the difference decreases. In the 3 mm/3% standard, both groups met the clinical requirement of gamma passing rate of >95%, but the Uniform group had a higher passing rate than the CT‐scan group.

Conclusions

Because the passing rate was higher in the Uniform group than in the CT‐scan group, it is recommended to use digital virtual phantom modules to generate verification plans in clinical practice.
Endothelium‐derived dopamine modulates EFS‐induced contractions of human umbilical vessels
Authors: Britto‐Júnior José , Pinheiro David H. A. , Justo Alberto F. O. , Figueiredo Murari Guilherme M. , Campos Rafael , Mariano Fernanda V. , de Souza Valéria B. , Schenka André A. , Mónica Fabiola Z. , Antunes Edson , De Nucci Gilberto
Published: June 2020

Electrical field stimulation (EFS) induces contractions of both snake aorta and human umbilical cord vessels (HUCV) which were dependent on the presence of the endothelium. This study aimed to establish the nature of the mediator(s) responsible for EFS‐induced contractions in HUCV. Rings with or without endothelium from human umbilical artery (HUA) or vein (HUV) were mounted in organ bath chambers containing oxygenated, heated Krebs‐Henseleit's solution. Basal release of dopamine (DA), noradrenaline, and adrenaline was measured by LC‐MS‐MS. Cumulative concentration‐response curves were performed with dopamine in the absence and in the presence of L‐NAME or of dopamine antagonists. EFS studies were performed in the presence and absence of L‐NAME, the α‐adrenergic blockers prazosin and idazoxan, and the dopamine antagonists SCH‐23390 and haloperidol. Tyrosine hydroxylase (TH) and dopa‐decarboxylase (DDC) were studied by immunohistochemistry and fluorescence in situ hybridizations. Basal release of dopamine requires an intact endothelium in both HUA and HUV. TH and DDC are present only in the endothelium of both HUA and HUV as determined by immunohistochemistry. Dopamine induced contractions in HUA only in the presence of L‐NAME. Dopamine‐induced contractions in HUV were strongly potentiated by L‐NAME. The EFS‐induced contractions in both HUA and HUV were potentiated by L‐NAME and inhibited by the D2‐like receptor antagonist haloperidol. The α‐adrenergic antagonists prazosin and idazoxan and the D1‐like receptor antagonist SCH‐23390 had no effect on the EFS‐induced contractions of HUA and HUV. Endothelium‐derived dopamine is a major modulator of HUCV reactivity in vitro.
Experimental removal of invasive Africanized honey bees increased breeding population size of the endangered Lear's macaw
Authors: Pacífico Erica C , Efstathion Caroline A , Filadelfo Thiago , Horsburgh Robert , Cunha Roberta A , Paschotto Fernanda R , Denes Francisco V , Gilardi James , Tella José L
Published: June 2020

BACKGROUND

Invasive Africanized honey bees potentially compete with cavity‐nesting birds in South America. However, the impacts of this competition and its conservation consequences to threatened species are poorly known. We quantified the presence of these bees and assessed their competition for cliff cavities used by nesting Lear's macaws Anodorhynchus leari, a globally endangered parrot endemic to the Caatinga biome of Brazil. We treated beehives with permethrin by shooting them with a crossbow bolt that distributed the compound upon impact. When feasible, we removed the comb and applied an insecticide (fipronil) to deter bee recolonization. We subsequently surveyed the macaw breeding population to verify whether our treatment allowed for nest recruitment in cavities previously occupied by bees.

RESULTS

We recorded > 100 beehives in the nesting cliffs. Hives outnumbered macaw nests tenfold in two areas recently recolonized by macaws. Cavities occupied by bees were significantly higher than those occupied by macaws, suggesting that macaws may be forced to breed in lower cavities. None of the untreated cavities (n = 50) were occupied by nesting macaws, whereas 15% of treated cavities (n = 52) were occupied within 2 years post treatment. Treated cavities occupied by macaws were significantly higher than those not occupied. Hive management increased macaw breeding population by 71% of the macaw breeding population increase.

CONCLUSION

Experimental hive treatments were effective in restoring nesting resources lost due to bee infestation. An intensive and continued eradication program is recommended to enhance macaw habitat restoration, facilitating its expansion into historical areas. © 2020 Society of Chemical Industry
Postgraduate migration behaviour of international university students supported from the Czech Development Cooperation scholarships
Authors: Novotný Josef , Feřtrová Marie , Jungwiertová Lucie
Published: June 2020

The development impacts of international scholarships for students from the Global South are most commonly understood through the expansion of human capital in the students' home countries for which the scholars' return analysed in this paper represents a key prerequisite. Utilising the theory of planned behaviour, this paper examines factors influencing the plans to return and actual postgraduation migration behaviour of 430 grantees of the Czech scholarship programme financed from the official development aid. One half of the current grantees reported plan to return, and only the 31% of alumni respondents actually returned suggesting a risk of brain drain. We found that economic integration rather than perceived sociocultural integration influences migration decision making of international students. We show how the propensity to return to scholars' home countries can be estimated from cross‐sectional data. A graphical path model was developed, which helps to understand drivers of postgraduate migration behaviour of international students.
A further insight into methyltestosterone metabolism: New evidences from in vitro and in vivo experiments
Authors: Martinez‐Brito Dayamin , Iannone Michele , Tatangelo Maria Antonietta , Molaioni Francesco , de la Torre Xavier , Botrè Francesco
Published: June 2020

Rationale

Although the metabolism of methyltestosterone (MT) has been extensively studied since the 1950s using different techniques, the aim of this study was to investigate the hydroxylation in positions C2, C4 and C6 after in vitro experiments and in vivo excretion studies using gas chromatography time‐of‐flight (GC/TOF) and gas chromatography/tandem mass spectrometry (GC/MS/MS). The results could be influenced by the mass spectrometric analyser used.

Methods

Incubations were carried out with human liver microsomes and six enzymes belonging to the cytochrome P450 family using MT as a substrate. The trimethylsilyl derivatives of the samples were analysed using GC/TOF and GC/MS/MS once the correct MS/MS transitions had been selected, mainly for 6‐hydroxymethyltestosterone (6‐OH‐MT) to avoid artefact interferences. A urinary excretion study was then performed after the administration of a 10 mg single oral dose of MT to a volunteer.

Results

The formation of hydroxylated metabolites of MT in the C6, C4 and C2 positions after both in vitro and in vivo experiments was observed. Sample evaluation using GC/TOF showed an interference for 6‐OH‐MT that could only be resolved in GC/MS/MS by monitoring specific transitions. The transitory detection of these hydroxylated metabolites in urine agrees with previous investigations that had described this metabolic route as being of little significance.

Conclusions

In doping analysis, the formation of 4‐hydroxymethyltestosterone (oxymesterone) from MT cannot be underestimated. Although it is only detected as a minor and short‐term excretion metabolite, it cannot be overlooked as it was found in both in vitro and in vivo experiments. The use of a combination of different mass spectrometric instruments allowed reliable conclusions to be reached, and it was shown that special attention must be given to artefact formation.