bluuebunny/crossref_metadata_2025 huggingface dataset:
Methylene blue offers neuroprotection after intracerebral hemorrhage in rats through the PI3K/Akt/GSK3β signaling pathway
Authors: Chen Chunli , Zhou Fangfang , Zeng Liuwang , Jiang Zheng , Hu Zhiping
Published: September 2018

Inflammation and apoptosis are two key factors contributing to secondary brain injury after intracerebral hemorrhage (ICH). In the present study, we explored the neuroprotective role of methylene blue (MB) in ICH rats and studied the potential mechanisms involved. Rats were subjected to local injection of collagenase IV in the striatum or sham surgery. We observed that MB treatment could exert a neuroprotective effect on ICH by promoting neurological scores, decreasing the brain water content, alleviating brain–blood barrier disruption, and improving the histological damages in the perihematomal areas. Furthermore, we demonstrated that the various mechanisms underlying MB’s neuroprotective effects linked to inhibited apoptosis and inhibited neuroinflammation. In addition, wortmannin, a selective inhibitor of phosphoinositide 3‐kinase (PI3K), could reverse the antiapoptotic and anti‐inflammatory effects of MB, which suggested that the PI3K–Akt pathway played an important role. In conclusion, these data suggested that MB could inhibit apoptosis and ameliorate neuroinflammation after ICH, and its neuroprotective effects might be exerted via the activation of the PI3K/Akt/GSK3β pathway.
Improvement of Duchenne muscular dystrophy phenotype following obestatin treatment
Authors: González‐Sánchez Jessica , Sánchez‐Temprano Agustín , Cid‐Díaz Tania , Pabst‐Fernández Regina , Mosteiro Carlos S. , Gallego Rosalía , Nogueiras Ruben , Casabiell Xesús , Butler‐Browne Gillian S. , Mouly Vincent , Relova José Luis , Pazos Yolanda , Camiña Jesús P.
Published: September 2018

Background

This study was performed to test the therapeutic potential of obestatin, an autocrine anabolic factor regulating skeletal muscle repair, to ameliorate the Duchenne muscular dystrophy (DMD) phenotype.

Methods and results

Using a multidisciplinary approach, we characterized the ageing‐related preproghrelin/GPR39 expression patterns in tibialis anterior (TA) muscles of 4‐, 8‐, and 18‐week‐old mdx mice (n = 3/group) and established the effects of obestatin administration at this level in 8‐week‐old mdx mice (n = 5/group). The findings were extended to in vitro effects on human immortalized DMD myotubes. An analysis of TAs revealed an age‐related loss of preproghrelin expression, as precursor of obestatin, in mdx mice. Administration of obestatin resulted in a significant increase in tetanic specific force (33.0% ± 1.5%, P < 0.05), compared with control mdx mice. Obestatin‐treated TAs were characterized by reduction of fibres with centrally located nuclei (10.0% ± 1.2%, P < 0.05) together with an increase in the number of type I fibres (25.2% ± 1.7%, P < 0.05) associated to histone deacetylases/myocyte enhancer factor‐2 and peroxisome proliferator‐activated receptor‐gamma coactivator 1α axis, and down‐regulation of ubiquitin E3‐ligases by inactivation of FoxO1/4, indexes of muscle atrophy. Obestatin reduced the level of contractile damage and tissue fibrosis. These observations correlated with decline in serum creatine kinase (58.8 ± 15.2, P < 0.05). Obestatin led to stabilization of the sarcolemma by up‐regulation of utrophin, α‐syntrophin, β‐dystroglycan, and α7β1‐integrin proteins. These pathways were also operative in human DMD myotubes.

Conclusions

These results highlight the potential of obestatin as a peptide therapeutic for preserving muscle integrity in DMD, thus allowing a better efficiency of gene or cell therapy in a combined therapeutic approach.
Bisphenol A affects neural development of the ascidian Ciona robusta
Authors: Messinetti Silvia , Mercurio Silvia , Pennati Roberta
Published: September 2018

Bisphenol A (BPA) is an organic pollutant derived from plastic degradation that has numerous and variable adverse effects on human health and wildlife. In particular, it has been reported that BPA can alter reproductive processes and nervous system development in vertebrates. Considering BPA presence in marine environment and the scant data available on its interaction with nervous system development, we analyzed the effect of BPA exposure on sperm viability, fertilization, embryogenesis, and neural differentiation of the ascidian Ciona robusta. Ascidians are members of the Phylum Tunicata, the sister group of Vertebrata, sharing with them fundamental developmental processes. Our results showed that first cell division was altered starting from 5 µM concentration. Lethal concentration (LC
50) was estimated to be 5.2 µM. Larvae developed from treated embryos showed specific malformations to the pigment cells even at 0.1 µM, corresponding to the highest environmental concentration reported so far. Moreover, GABAergic and dopaminergic neurons proved to be target organs of BPA teratogenic action, in accordance with similar results reported in vertebrate animal models. Overall, our results suggest that BPA can exert its effects on nervous system acting on different pathways and underline that
C. robusta is a valuable invertebrate animal model for preliminary screenings of effects of pollutants on vertebrates.
Frequency Offset Corrected Inversion Pulse for B0 and B1 Insensitive Fat Suppression at 3T: Application to MR Neurography of Brachial Plexus
Authors: Wang Xinzeng , Greer Joshua S. , Dimitrov Ivan E. , Pezeshk Parham , Chhabra Avneesh , Madhuranthakam Ananth J.
Published: September 2018

Background

The 3D short tau inversion recovery (STIR) sequence is routinely used in clinical MRI to achieve robust fat suppression. However, the performance of the commonly used adiabatic inversion pulse, hyperbolic secant (HS), is compromised in challenging areas with increased B0 and B1 inhomogeneities, such as brachial plexus at 3T.

Purpose

To demonstrate the frequency offset corrected inversion (FOCI) pulse as an efficient fat suppression STIR pulse with increased robustness to B0 and B1 inhomogeneities at 3T, compared to the HS pulse.

Study Type

Prospective.

Subjects/Phantom

Initial evaluation was performed in phantoms and one healthy volunteer by varying the B1 field, while subsequent comparison was performed in three healthy volunteers and five patients without varying the B1.

Field Strength/Sequence

3T; 3D TSE‐STIR with HS and FOCI pulses.

Assessment

Brachial plexus images were qualitatively evaluated by two musculoskeletal radiologists independently using a four‐point grading scale for fat suppression, shading artifacts, and nerve visualization.

Statistical Test

The Wilcoxon signed‐rank test with P < 0.05 was considered statistically significant.

Results

Simulations and phantom experiments demonstrated broader bandwidth (2.5 kHz vs. 0.83 kHz, increased B0 robustness) at the same adiabatic threshold and lower adiabatic threshold (5 μT vs. 7 μT at 3.5 ppm, increased B1 robustness) at the same bandwidth with the FOCI pulse compared to the HS pulse With increased bandwidth, the FOCI pulse achieved robust fat suppression even at 50% of maximum B1 strength, while the HS pulse required >75% of maximum B1 strength. Compared to the standard 3D TSE‐STIR with HS pulse, the FOCI pulse achieved uniform fat suppression (P < 0.05), better nerve visualization (P < 0.05), and minimal shading artifacts (P < 0.01) in brachial plexus at 3T.

Data Conclusion

The FOCI pulse has increased robustness to B0 and B1 inhomogeneities, compared to the HS pulse, and enables uniform fat suppression in brachial plexus at 3T.

Level of Evidence: 1

Techinical Efficacy: Stage 1

J. Magn. Reson. Imaging 2018;48:1104–1111.
Red nucleus interleukin‐1β evokes tactile allodynia through activation of JAK/STAT3 and JNK signaling pathways
Authors: Guo Yi‐Jie , Li Hao‐Nan , Ding Cui‐Ping , Han Shui‐Ping , Wang Jun‐Yang
Published: September 2018

We previously reported that interleukin‐1β (IL‐1β) in the red nucleus (RN) is involved in pain modulation and exerts a facilitatory effect in the development of neuropathic pain. Here, we explored the actions of signaling pathways, including the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3), c‐Jun N‐terminal kinase (JNK), extracellular signal‐regulated kinase (ERK), p38 mitogen‐activated protein kinase (p38 MAPK) and nuclear factor‐κB (NF‐κB) pathways, on RN IL‐1β‐mediated pain modulation. After a single dose of recombinant rat IL‐1β (rrIL‐1β, 10 ng) injected into the RN in normal rats, a tactile allodynia was evoked in the contralateral but not ipsilateral hindpaw, commencing 75 min and peaking 120 min postinjection. Up‐regulated protein levels of phospho‐STAT3 (p‐STAT3) and p‐JNK were observed in the RN 120 min after rrIL‐1β injection, the increases of p‐STAT3 and p‐JNK were blocked by anti‐IL‐1β antibody. However, the expression levels of p‐ERK, p‐p38 MAPK, and NF‐κB in the RN were not affected by rrIL‐1β injection. RN neurons and astrocytes contributed to IL‐1β‐evoked up‐regulation of p‐STAT3 and p‐JNK. Further studies demonstrated that injection of the JAK2 antagonist AG490 or JNK antagonist SP600125 into the RN 30 min prior to the administration of rrIL‐1β could completely prevent IL‐1β‐evoked tactile allodynia, while injection of the ERK antagonist PD98059, p38 MAPK antagonist SB203580, or NF‐κB antagonist PDTC did not affect IL‐1β‐evoked tactile allodynia. In conclusion, our data provide additional evidence that RN IL‐1β is involved in pain modulation, and that it exerts a facilitatory effect by activating the JAK/STAT3 and JNK signaling pathways.
Periodontitis causes abnormalities in the liver of rats
Authors: Vasconcelos Any Carolina Cardoso Guimarães , Vasconcelos Daniel Fernando Pereira , Pereira da Silva Felipe Rodolfo , de Carvalho França Luiz Felipe , Alves Even Herlany Pereira , Lenardo David Di , dos Santos Pessoa Larissa , Novaes Pedro Duarte , Luiz dos Reis Barbosa André , Mani Arya , Mariano Flávia Sammartino , Medeiros Jand‐Venes Rolim , de Oliveira Aldeídia Pereira
Published: September 2018

Background

Periodontitis not only causes injury to the periodontium, but also damages other tissues such as: articulate, renal, cardiac, and hepatic. The objective of this study was to investigate periodontitis induced alterations in liver function and structure using an experimental model.

Methods

Twenty female rats (Rattus norvegicus) were allocated into two groups: control and periodontitis. Gingival bleeding index and oxidative stress parameters and specific circulating biomarkers were measured. Immunohistochemistry was carried out using alkaline phosphatase (AlkP) staining of the liver. Hepatic tissues, cytokines, and lipid contents were measured. Histopathologic evaluation of the liver was carried out using light and electron microscopy.

Results

Liver histopathologic and immunohistochemistry assessment showed increase in steatosis score, and presence of binucleate hepatocytes and positive cells for AlkP in periodontitis versus control group. Ultrastructural evaluation showed significant increase in size and number of lipid droplets (LD), distance between the cisterns of rough endoplasmic reticulum (RER), mitochondria size, foamy cytoplasm, and glycogen accumulation in the liver of the periodontitis group compared with the control group. In addition, plasma levels of AlkP, high‐density lipoprotein (HDL), triglycerides, and total cholesterol were also changed.

Conclusion

Experimental periodontitis caused immunohistochemistry, histopathologic, ultrastructural, oxidative, and biochemical changes in the liver of rats.
Marine geomorphological record of Ice Sheet development in East Greenland since the Last Glacial Maximum
Authors: Arndt Jan Erik
Published: September 2018

Reconstructions of ice sheet development in East Greenland, since the Last Glacial Maximum (LGM), are poorly constrained. This study compiles swath bathymetric data from five expeditions, to investigate the geomorphology of three glacier outlet systems (Kejser Franz Joseph Fjord, Kong Oscar Fjord, and Scoresby Sund) and reconstruct the post‐LGM ice dynamics and extent. The landforms suggest that ice streams probably reached the shelf edge, via cross‐shelf troughs, in all three systems at the LGM. Off Scoresby Sund, it remains unresolved as to whether a mid‐shelf grounding zone wedge marks a recessional stage or the LGM extent. In the Allerød–Bølling interstadial, ice retreated to the fjord entrances at Kejser Franz Joseph Fjord and Kong Oscar Fjord, as documented by partly overridden terminal moraines, and most probably into the fjord at Scoresby Sund. Subsequent overriding occurred by ice readvance, probably in the Younger Dryas. Large ice‐marginal deposition features, formed on the mid‐shelf and at the entrance of Scoresby Sund, probably mark the maximum ice‐sheet extent after the readvance. Holocene retreat was rapid, except for two phases of stabilization at the entrance of Kong Oscar Fjord. Landslide debris indicates that at least one tsunami affected Scoresby Sund at some time in the Holocene.
Effect of Sodium Halide on Micellar and Surface Properties of Cationic Silicone Surfactants
Authors: Tan Jinglin , Shao Jufang , Tian Cuiping , Liao Zhiman , Yan Ping
Published: September 2018

The effect of sodium halide on aggregation behavior of four cationic silicone surfactants, Si3mamCl, Si4mamCl, Si4PyCl, and Si4minCl, in solution was investigated using surface tension and conductivity measurements. The ability of sodium halide (NaCl, NaBr, and NaI) to reduce critical micelle concentration (CMC) values was in the order NaI > NaBr > NaCl. However, the
γCMC values of the cationic silicone surfactants, Si4mamCl, Si4PyCl and Si4minCl, in sodium halide solution are almost the same as those of the salt‐free system. The values of and are negative, indicating that the micellization process and adsorption of the four cationic silicone surfactants at the air‐solution interface are spontaneous.
An environmentally friendly method for the enantioseparation and determination of benalaxyl in tobacco and soil by ultra‐performance convergence chromatography with tandem mass spectrometry
Authors: Yang Fei , Tang Gangling , Li Zhonghao , Fan Ziyan , Wang Ying , Liu Shanshan , Bian Zhaoyang , Deng Huimin
Published: September 2018

For the purpose of chiral separation and determination of benalaxyl enantiomers in tobacco and soil, we developed a rapid, green, and sensitive method using ultra‐performance convergence chromatography with tandem mass spectrometry. The samples were extracted and purified by the quick, easy, cheap, effective, rugged, and safe method before injection. The baseline separation was obtained on a chiral column in 5 min with carbon dioxide and ethanol as mobile phase. Separation parameters were optimized for the best separation efficiency. Under optimal conditions, the recoveries of both enantiomers were 77.1–98.4% with relative standard deviations <5.0% at spiked level of 0.1, 2.0, and 5.0 mg/kg in two matrices. Good coefficients of determination were achieved over the concentration range of 10–250 ng/mL. The limit of detection and the limit of quantification for all enantiomers ranged from 0.43 to 0.72 μg/kg and from 1.25 to 2.15 μg/kg, respectively. The results show that ultra‐performance convergence chromatography with tandem mass spectrometry provides a reliable, green, and rapid method for the separation and determination of benalaxyl enantiomers in tobacco and soil. This method has important theoretical significance for studying the enantioselectivity and bioactivity of benalaxyl in the environment and in organisms.
Measuring Intraventricular Pressure Using Ultrasound Elastography
Authors: Vejdani‐Jahromi Maryam , Freedman Jenna , Trahey Gregg E. , Wolf Patrick D.
Published: September 2018

Objectives

Intraventricular pressure (IVP) is one of the most important measurements for evaluating cardiac function, but this measurement is not currently easily assessable in the clinic. The primary reason for this is the absence of a noninvasive technique for measuring IVP. In this study, we investigate the relationship between IVP and dynamic myocardial stiffness measured by shear wave elasticity imaging (SWEI) and assess the feasibility of measuring IVP using SWEI.

Methods

In 8 isolated working rabbit hearts, IVP was recorded in the left ventricle using a pressure catheter. Simultaneously, myocardial stiffness was recorded by SWEI. Using the peak values for IVP and SWEI measured stiffness, SWEI measurements were calibrated and converted to IVP.

Results

A linear relationship with zero intercept was observed between IVP and SWEI, with the average slope of 0.318 kPa/mm Hg, R2 = 0.89. Using one point on the IVP/SWEI curve, SWEI measurements were converted to IVP. Estimated pressure using SWEI and IVP were linearly correlated with the slope of 0.95, R2 = 0.88 (mean end diastolic pressure by pressure catheter = 12.716 mm Hg and by SWEI=14.726 mm Hg), indicating the near equivalence of the 2 measurements.

Conclusion

We have shown that SWEI measurements are linearly related to IVP; therefore, pressure‐based indices could potentially be derived from SWEI ultrasound elastography. The feasibility of using SWEI to estimate IVP with a single point calibration was also shown in this study.
Natural regeneration on land degraded by coal mining in a tropical climate: Lessons for ecological restoration from Indonesia
Authors: Novianti Vivi , Marrs Rob H. , Choesin Devi N. , Iskandar Djoko T. , Suprayogo Didik
Published: September 2018

There are few examples of primary succession from tropical conditions, especially on land degraded by human activity, for example, mine wastes. Such studies would assist in informing ecological restoration of these degraded sites. Here, a chronosequence approach was used to investigate early‐stage primary succession on overburden spoil wastes derived from coal mining in a tropical climate over a 64‐month period. Plant species composition and several microclimatic and spoil physicochemical and microbial properties were measured, and responses analysed using regression and multivariate (nonmetric multidimensional scaling) analyses. A clear primary successional process was described showing that vegetation cover and species richness generally increased through time with a successional pathway from graminoids and herbs as the early dominants, shrubs in midsuccession, and trees in the later‐successional stages. Two important differences were noted between our results and primary successions elsewhere; a lower abundance of nitrogen‐fixing species and the colonization by some late‐successional shrubs and trees at the start. During the succession, aggregate stability and organic matter (total C) increased—whereas electrical conductivity and some potentially toxic elements (Al, B) decreased. The constant high spoil moisture content appears to be an important determinant of vegetation development during primary succession and may be a factor in the rapid pace of succession detected here. The lessons for ecological restoration for coal overburden spoil under tropical conditions are that succession can proceed relatively rapidly.
Lack of consensus about indigenous soil knowledge among wet rice farmers in a Thai‐Lao village in Northeast Thailand
Authors: Yodda Sujitra , Rambo A. Terry
Published: September 2018

Most ethnopedological research has been based on information collected in group interviews. Resulting descriptions of indigenous soil taxonomies represent group consensus views and ignore variations among individuals. In this study, 11 Thai‐Lao farmers in a village in Northeast Thailand were individually interviewed about their knowledge of local paddy soils. They identified 14 named soils in their fields. Texture, color, softness, and taste were the main indicators employed to identify soils, with texture the most commonly used criterion. Agreement among informants about the names of the various soil types was surprisingly low, with as many as seven names applied to the same soil type. The farmers also differed in the ways they classified the different soil types into larger groups; six farmers divided them into four groups, and five farmers divided them into three groups. This lack of consensus about soil names and classification among members of the same small community may reflect the way that villagers acquire their knowledge of soils. Soil knowledge is transmitted vertically from parents to their children within families but is rarely or never shared horizontally with fellow villagers. Soil knowledge is a type of familial microculture rather than a widely shared body of knowledge within the whole community. This finding suggests that land use planners and rural development practitioners should be cautious in basing their plans for community management of soil resources on existing studies of indigenous soil knowledge without first establishing how widely shared this knowledge is among community members.
Individual‐based modeling explains the contrasted seasonality in size, growth, and reproduction of the sympatric Arctic (Thysanoessa raschii) and Nordic krill (Meganyctiphanes norvegica) in the St. Lawrence Estuary, eastern Canada
Authors: Benkort D. , Plourde S. , Winkler G. , Cabrol J. , Ollier A. , Cope L.‐E. , Maps F.
Published: September 2018

The Nordic krill Meganyctiphanes norvegica and Arctic krill Thysanoessa raschii both dominate the krill community within the Estuary and Gulf of St. Lawrence system where they are central forage species for its pelagic ecosystem. We developed a species‐specific physiological individual based model that implements the critical physiological processes of growth, molting, and reproduction of female adults as responses to environmental forcing. Key innovations of our approach were the decoupling between the molting schedule and growth, as well as considering two distinct sources of prey (phytoplankton and mesozooplankton). Our simulation results revealed that the details of the feeding process were critical for an accurate representation of the production dynamics of adult individuals from both species. Their specific feeding preferences on phytoplankton and mesozooplankton resulted in distinct species‐specific phenological patterns that reproduced observations. The present study highlights the importance of detailed knowledge of diet and feeding behavior of krill species to improve our understanding of population responses in a rapidly changing environment.
HToPred: A Tool for Human Topoisomerase II Inhibitor Prediction
Authors: Tripathi Neha , Shaikh Naeem , Bharatam Prasad V. , Garg Prabha
Published: September 2018

The enzyme human topoisomerase IIα (hTopoIIα) is an important anticancer drug target. Due to the availability of multiple inhibitor‐binding sites in this enzyme, the anti‐hTopoII agents possess high chemical diversity. Chemoinformatics methods can be used to identify lead compounds from large databases for hTopoII inhibitory activity and classify them. In this work, we report the use of machine learning methods to develop classification models for the identification of possible anti‐hTopoIIα agents and to classify them as catalytic inhibitors vs. poisons. Initially, an extensive dataset of small molecules which are reported to be evaluated towards hTopoIIα inhibition was collected from ChEMBL database and literature. Using this dataset, predictive models for classifying small molecules into hTopoIIα inhibitors and non‐inhibitors were developed. Additionally, the model development was taken up for the prediction of the type of hTopoIIα inactivation. Several molecular fingerprints and physicochemical descriptors of the molecules in the dataset were calculated using the chemoinformatics tool RDKit. Various classifiers were evaluated to establish suitable protocol. Further, ensemble models were developed by bagging of homogenous classifier and selective fusion of heterogeneous classifiers. The models were thoroughly validated with 5‐fold cross validation and external validation. The best performing models were incorporated into a tool christened as Human Topoisomerase IIα Inhibitor Prediction (HToPred, http://14.139.57.41/HToPred). A molecular docking based validation for the successful application of HToPred in predicting the mode of enzyme inhibition was performed, which further established the acceptability of this tool. This tool can serve as an important platform to prescreen compounds for anti‐hTopoIIα potential.
Automatic localization of closely spaced cochlear implant electrode arrays in clinical CTs
Authors: Zhao Yiyuan , Dawant Benoit M. , Labadie Robert F. , Noble Jack H.
Published: September 2018

Purpose

Cochlear implants (CIs) are neural prosthetic devices that provide a sense of sound to people who experience profound hearing loss. Recent research has indicated that there is a significant correlation between hearing outcomes and the intracochlear locations of the electrodes. We have developed an image‐guided cochlear implant programming (IGCIP) system based on this correlation to assist audiologists with programming CI devices. One crucial step in our IGCIP system is the localization of CI electrodes in postimplantation CTs. Existing methods for this step are either not fully automated or not robust. When the CI electrodes are closely spaced, it is more difficult to identify individual electrodes because there is no intensity contrast between them in a clinical CT. The goal of this work is to automatically segment the closely spaced CI electrode arrays in postimplantation clinical CTs.

Methods

The proposed method involves firstly identifying a bounding box that contains the cochlea by using a reference CT. Then, the intensity image and the vesselness response of the VOI are used to segment the regions of interest (ROIs) that may contain the electrode arrays. For each ROI, we apply a voxel thinning method to generate the medial axis line. We exhaustively search through all the possible connections of medial axis lines. For each possible connection, we define CI array centerline candidates by selecting two points on the connected medial axis lines as the array endpoints. For each CI array centerline candidate, we use a cost function to evaluate its quality, and the one with the lowest cost is selected as the array centerline. Then, we fit an a priori known geometric model of the array to the centerline to localize the individual electrodes. The method was trained on 28 clinical CTs of CI recipients implanted with three models of closely spaced CI arrays. The localization results are compared with the ground truth localization results manually generated by an expert.

Results

A validation study was conducted on 129 clinical CTs of CI recipients implanted with three models of closely spaced arrays. Ninety‐eight percent of the localization results generated by the proposed method had maximum localization errors lower than one voxel diagonal of the CTs. The mean localization error was 0.13 mm, which was close to the rater's consistency error (0.11 mm). The method also outperformed the existing automatic electrode localization methods in our validation study.

Conclusion

Our validation study shows that our method can localize closely spaced CI arrays with an accuracy close to what is achievable by an expert on clinical CTs. This represents a crucial step toward automating IGCIP and translating it from the laboratory to the clinical workflow.
Content‐oriented sparse representation (COSR) for CT denoising with preservation of texture and edge
Authors: Xie Huiqiao , Niu Tianye , Tang Shaojie , Yang Xiaofeng , Kadom Nadja , Tang Xiangyang
Published: September 2018

Purpose

Denoising has been a challenging research subject in medical imaging, since the suppression of noise conflicts with the preservation of texture and edges. To address this challenge, we develop a content‐oriented sparse representation (COSR) method for denoising in computed tomography (CT).

Methods

An image is segmented into a number of content areas and each of them consists of similar material. Having been ex‐painted, each content area is sparsely coded using the dictionary learnt from patches extracted from the corresponding content area. By constraining sparsity, noise is suppressed and the final image is formed by aggregating all denoised content areas. The performance of COSR method is examined with images simulated by computer and generated by multidetector row CT (MDCT), cone beam CT (CBCT), and micro‐CT, in which water phantom, anthropomorphic phantom, a human subject, and a small animal are engaged, using the figures of merit, such as standard division (SD), contrast to noise ratio (CNR), and thresholded edge keeping index (EKIth) and structural similarity index (SSIM). In addition, the optimization of performance by parameter tuning is also investigated.

Results

Quantitatively gauged by metrics of noise, EKIth and SSIM, the performance evaluation shows that the proposed COSR method is effective in denoising (>50% reduction in noise) while it outperforms the conventional sparse representation method in preservation of texture and edge by ~20% (gauged by SSIM). It has also been shown that the COSR method is tolerable to inaccuracy in content area segmentation and variation in dictionary learning. Moreover, the computational efficiency of COSR can be substantially improved using prelearnt dictionaries.

Conclusions

The COSR method would find its utility in clinical and preclinical applications, such as low‐dose CT, image segmentation, registration, and computer‐aided diagnosis. The proposal of COSR denoising is of innovation and significance in the theory and practice of denoising in medical imaging. A demonstration code package is available at https://github.com/xiehq/COSR.
Technical Note: Characterization of clinical linear accelerator triggering latency for motion management system development
Authors: Shepard Andrew J. , Matrosic Charles K. , Radtke Jeffrey L. , Jupitz Sydney A. , Culberson Wesley S. , Bednarz Bryan P.
Published: September 2018

Purpose

Latencies for motion management systems have previously been presented as guidelines for system development and implementation. These guidelines consider the overall system latency, including data acquisition, algorithm processing, and linac triggering time. However, during system development, the triggering latency of the clinical linear accelerator is often considered fixed. This paper presents a method to decouple the linac‐only triggering latency from the total system latency such that latency can be considered in terms of only the linac‐independent aspects of the system.

Methods

The linac‐only latency was investigated by considering the time at which a linac response was observed relative to the time at which a beam‐on/off triggering signal was sent to the linac. The relative time between the two signals was analyzed using a multichannel oscilloscope with input signals from a custom gating box to manually trigger the beam state as well as a diode positioned at beam isocenter to monitor the linac response. The beam‐on/off latency was measured at multiple energies (6/18 MV) and repetition rates (100–600 MU/min) to investigate beam setting dependencies.

Results

The measured latency was observed to be dependent on the accelerator settings for repetition rate and energy, with beam‐on latencies decreasing with increasing repetition rate and decreasing energy. In contrast, the opposite trend was present for the observed beam‐off latency. At 600 MU/min, beam‐on/off latencies were observed to be 3.37/1.45 ms for a 6 MV beam and 6.02/0.73 ms for an 18 MV beam. Negative latencies were possible for beam‐off measurements due to the mechanical latency being less than the pulse separation at given repetition rates.

Conclusions

The linac latency associated with triggering the beam‐on/off was determined to have a minor contribution to the total allowable system latency; thus, the majority of the total system latency can be attributed to linac‐independent factors.
Toward 7T breast MRI clinical study: safety assessment using simulation of heterogeneous breast models in RF exposure
Authors: Li Xin , Rispoli Joseph V.
Published: September 2018

Purpose

To facilitate assessment of RF power deposition and temperature rise within the breast, we present a method to seamlessly join heterogeneous breast models with standard whole‐body models and demonstrate simulations at 7 T.

Methods

Finite‐difference time‐domain electromagnetic and bioheat simulations are performed to analyze the specific absorption rate (SAR) and temperature rise distributions in 36 Breast Imaging Reporting and Data System (BI‐RADS) categorized breast models fused to 2 female whole‐body models while transmitting from a 7T breast volume coil. The breast models are uncompressed in the prone position and feature heterogeneous tissue contents; fusion with human models uses affine transformation and the level‐set method.

Results

The fusion method produces a continuous transient from the chest region to the posterior portion of breast models while preserving the original volume and shape of breast models. Simulation results of both Ella and Hanako models indicate that the maximum local SAR, partial body SAR, and local tissue temperature rise are positively correlated with both breast density and the highest BI‐RADS density classification. Additionally, maximum local tissue temperature rise is positively correlated with maximum 10‐g SAR values.

Conclusion

Fibroglandular tissue content plays an important role in the distribution of SAR and temperature rise within breast tissue. The combined body‐breast models preserve the integrity of breast models while concurrently exhibiting the loading of whole‐body human models. The procedures presented in this simulation study facilitate safety assessments for breast MRI across the population at both clinical and ultrahigh field strengths.
Fast quantitative MRI using controlled saturation magnetization transfer
Authors: A.G. Teixeira Rui Pedro , Malik Shaihan J. , Hajnal Joseph V.
Published: September 2018

Purpose

This study demonstrates magnetization transfer (MT) effects directly affect relaxometry measurements and develops a framework that allows single‐pool models to be valid in 2‐pool MT systems.

Methods

A theoretical framework is developed in which a 2‐pool MT system effectively behaves as a single‐pool if the RMS RF magnetic field ({\text{B}}_{1}^{{{\text{rms}}}}) is kept fixed across all measurements. A practical method for achieving controlled saturation magnetization transfer (CSMT) using multiband RF pulses is proposed. Numerical, Phantom, and in vivo validations were performed directly comparing steady state (SS) estimation approaches that under correct single‐pool assumptions would be expected to vary in precision but not accuracy.

Results

Numerical simulations predict single‐pool estimates obtained from MT model generated data are not consistent for different SS estimation methods, and a systematic underestimation of T2 is expected. Neither effect occurs under the proposed CSMT approach. Both phantom and in vivo experiments corroborate the numerical predictions. Experimental data highlights that even when using the same relaxometry method, different estimates are obtained depending on which combination of flip angles (FAs) and TRs are used if the CSMT approach is not used. Using CSMT, stable measurements of both T1 and T2 are obtained. The measured T1 ) depends on {\text{B}}_{1}^{{{\text{rms}}}}, which is therefore an important parameter to specify.

Conclusion

This work demonstrates that conventional single pool relaxometry, which is highly efficient for human studies, results in unreliable parameter estimates in biological tissues because of MT effects. The proposed CSMT framework is shown to allow single‐pool assumptions to be valid, enabling reliable and efficient quantitative imaging to be performed.
Caval to pulmonary 3D flow distribution in patients with Fontan circulation and impact of potential 4D flow MRI error sources
Authors: Jarvis Kelly , Schnell Susanne , Barker Alex J. , Rose Michael , Robinson Joshua D. , Rigsby Cynthia K. , Markl Michael
Published: September 2018

Purpose

Uneven flow distribution in patients with Fontan circulation is suspected to lead to complications. 4D flow MRI offers evaluation using time‐resolved pathlines; however, the potential error is not well understood. The aim of this study was to systematically assess variability in flow distribution caused by well‐known sources of error.

Methods

4D flow MRI was acquired in 14 patients with Fontan circulation. Flow distribution was quantified by the % of caval venous flow pathlines reaching the left and right pulmonary arteries. Impact of data acquisition and data processing uncertainties were investigated by (1) probabilistic 4D blood flow tracking at varying noise levels, (2) down‐sampling to mimic acquisition at different spatial resolutions, (3) pathline calculation with and without eddy current correction, and (4) varied segmentation of the Fontan geometry to mimic analysis errors.

Results

Averaged among the cohort, uncertainties accounted for flow distribution errors from noise ≤3.2%, low spatial resolution ≤2.3% to 3.8%, eddy currents ≤6.4%, and inaccurate segmentation ≤3.9% to 9.1% (dilation and erosion, respectively). In a worst‐case scenario (maximum additive errors for all 4 sources), flow distribution errors were as high as 22.5%.

Conclusion

Inaccuracies related to postprocessing (segmentation, eddy currents) resulted in the largest potential error (≤15.5% combined) whereas errors related to data acquisition (noise, low spatial resolution) had a lower impact (≤5.5%‐7.0% combined). Whereas it is unlikely that these errors will be additive or affect the identification of severe asymmetry, these results illustrate the importance of eddy current correction and accurate segmentation to minimize Fontan flow distribution errors.
Ultrasound in the management of iatrogenic spinal accessory nerve palsy at the posterior cervical triangle area
Authors: Shen Jun , Chen Weimin , Ye Xuan , Qiu Yanqun , Xu Jing , Zhu Yi , Shen Yundong , Xu Wendong
Published: September 2018

Introduction: The purpose of this study was to evaluate the application of ultrasound in the management of iatrogenic spinal accessory nerve palsy at the posterior cervical triangle area. Methods: In this retrospective study, we compared ultrasonographic results with intraoperative findings in patients with iatrogenic spinal accessory nerve palsy during the time period from 2014 to 2018 at our hospital. Results: Eleven patients were included. Ultrasound detected nerve transections in 9 patients and continuities in 2 patients. The ultrasonographic results were consistent with the intraoperative findings. Furthermore, ultrasound was able to accurately reveal lesion location in 8 of 9 patients with nerve transections. Discussion: Ultrasound provides direct images about nerve lesions contributing to the diagnosis of iatrogenic spinal accessory nerve palsy at the posterior cervical triangle area and also reveals lesion location, assisting in formulating suitable surgical plans preoperatively. We recommend that ultrasound be integrated into the preoperative evaluation. Muscle Nerve 59:64–69, 2019
Novel Feed from Invasive Species is Beneficial to Walleye Aquaculture
Authors: Mejri Sahar , Tremblay Réjean , Vandenberg Grant , Audet Céline
Published: September 2018

Carnivorous fishes, such as the Walleye Sander vitreus, are nutritionally demanding for fish meal. A promising alternative to marine-origin fish meal, the supply of which has been stagnant in recent decades, is fish meal derived from undesirable freshwater species, such as the White Sucker Catostomus commersonii. To evaluate the relative value of such ingredients, we examined the growth performance of Walleye juveniles. Two dietary treatments were tested: an experimental (EXP) diet that was manufactured using White Sucker as fish meal in comparison with a commercial (COM) diet, EWOS Micro (EWOS Canada, Ltd.). Dietary lipid content was 15.1% and 16.8% for EXP and COM diets, respectively. The protein content was 50.4% and 57.6% for EXP and COM diets, respectively. The energy content was 5,098.76 ± 9.23 cal/g (mean ± SD) for the EXP diet and 5,134.47 ± 10.95 cal/g for the COM diet. Starting at 27 d posthatch, Walleye juveniles (initial weight [mean ± SD] = 0.03 ± 0.008 g; initial length = 15.7 ± 1.5 mm) were reared for 6 weeks in three replicate tanks for each treatment. Condition factor (0.83), final weight (1.12 ± 0.3 g), and weight gain (1.09 ± 0.06 g) were higher in fish that were fed the EXP diet. Similarly, the energetic lipid content of fish in the EXP treatment group (mean ± SD = 5.01 ± 0.45 g/kg) was also higher than that of fish fed the COM diet (3.30 ± 0.53 g/kg). Although the polar lipid content (membrane lipids) was similar in fish from the two treatments, the nutritional ratio for COM juveniles was over 1.5 for arachidonic acid and docosahexaenoic acid, indicating selective incorporation by juveniles and suggesting a potential dietary imbalance of these fatty acids. Furthermore, the higher observed selective incorporation of oleic acid in juveniles fed the EXP diet suggested that a higher value of this fatty acid in the EXP feed could have increased Walleye growth performance. Threonine was the main essential amino acid (AA; >18.5% of total AAs), while serine and glycine contributed the highest percentages of the nonessential AAs (>31% and 8.5% of total AAs, respectively). All three AAs, often considered limiting ingredients, are important to support growth and are involved in metabolic processes in some fish species. Our results demonstrate that feed pellets made with White Sucker fish meal improved growth in Walleye juveniles and can serve as a suitable and probably lower-cost regional alternative to marine fish meal in feeds for carnivorous fishes.
Effects of Different Levels of Marine Snail Shells in the Diets of Juvenile Kuruma Shrimps Marsupenaeus japonicus as a Source of Calcium
Authors: Moss Amina S , Ishikawa Manabu , Koshio Shunsuke , Yokoyama Saichiro , Dawood Mahmoud A O
Published: September 2018

Shells derived from marine mollusks represent over 80% of shellfish waste. Therefore, a 42-d feeding trial was conducted to assess the effects of different levels of snail shells (SS) in the diets of kuruma shrimps Marsupenaeus japonicus as a source of calcium (Ca). An evaluation of the ability of SS to replace Ca was done by applying principles from a previously researched condition index to quantify the external characteristics of juvenile kuruma shrimps (initial body weight, 0.12 ± 0.01 g each [mean ± SD]) with relation to their growth performance. Five diets were formulated to include increasing levels of SS at 0, 2, 5, 10, and 0% (D1, D2, D3, D4, and D5, respectively); D1 was the positive control with Ca and no SS, and D5 was the negative control with no SS and no Ca included in the diet. Each diet was randomly allocated to triplicate groups of 15 shrimps per tank in a flow-through system. Survival, body weight gain, specific growth rate, feed efficiency ratio, individual dry weight, total body length, condition index, freshwater stress resistance, and fatty acid composition were evaluated. Results indicated that shrimps fed 2% and 10% SS had significantly higher stress resistance than those fed the other diets (P < 0.05). Generally, dietary SS supplementation improved growth performances (such as final body weight, percent weight gain, specific growth rate, feed efficiency ratio), and the significantly highest performance was found in shrimps fed 10% SS (D4). Shrimps fed diets with ≤2% SS supplementation (D1, D2, and D5) had significantly lower condition index and hepatosomatic index. Under the present experimental conditions, using the condition index as a tool to evaluate the fitness of kuruma shrimps was beneficial; however, it was a poor indication of freshwater stress resistance. Instead, the ratio of n-3:n-6 in the shrimps’ bodies seemed to be correlated with stress resistance. Additionally, supplementing 10% SS in kuruma shrimp diets is recommended for better growth performance.
A decomposition approach to solve the selective graph coloring problem in some perfect graph families
Authors: Şeker Oylum , Ekim Tınaz , Taşkın Z. Caner
Published: September 2018

Graph coloring is the problem of assigning a minimum number of colors to all vertices of a graph such that no two adjacent vertices receive the same color. The selective graph coloring problem is a generalization of the standard graph coloring problem; given a graph with a partition of its vertex set into clusters, the objective is to choose exactly one vertex per cluster so that, among all possible selections, the number of colors necessary to color the vertices in the selection is minimum. This study focuses on a decomposition based exact solution framework for selective coloring in some perfect graph families: in particular, permutation, generalized split, and chordal graphs where the selective coloring problem is known to be NP‐hard. Our method combines integer programming techniques and combinatorial algorithms for the graph classes of interest. We test our method on graphs with different sizes and densities, present computational results and compare them with solving an integer programming formulation of the problem by CPLEX, and a state‐of‐the art algorithm from the literature. Our computational experiments indicate that our decomposition approach significantly improves solution performance in low‐density graphs, and regardless of edge‐density in the class of chordal graphs.
Managing occupational identity threats and job turnover: How former and current fundraisers manage moments of stigmatized identities
Authors: Meisenbach Rebecca J. , Rick Jessica M. , Brandhorst Jaclyn K.
Published: September 2018

Maintaining a strong group of fundraisers amidst high turnover rates is essential to the financial health of nonprofit organizations. One issue potentially harming fundraisers' success and continued presence in the field is the negative reputation sometimes associated with fundraising work. This exploratory study uses Stigma Management Communication Theory and content analysis of in‐depth interviews with current and former university fundraisers to investigate how fundraisers communicatively manage stigmatizing messages associated with their occupation. The findings suggest that current fundraisers use a greater number and variety of stigma management strategies than former fundraisers described using. The findings also highlight the potential consequences and distinctions among ways of using humor to manage stigma messages. These findings can be translated into orientation and training programs for fundraisers, teaching them successful ways of framing their occupations and work.
Main‐chain ionic liquid‐crystalline polymers bearing quaternary phosphonium ions
Authors: Bai Lu , Tang Xinqiao , Kong Shengwen , Song Ying , He Xiaozhi , Meng Fanbao
Published: September 2018

A series of quaternary phosphonium ions–containing main‐chain ionic liquid‐crystalline polymers with tri‐tolylphosphines as cationic groups have been synthesized and characterized. The molecular structures of all compounds have been determined. Test results show that the liquid crystal properties of the polymer, the quaternary phosphonium ions–containing main‐chain ionic liquid‐crystalline polymers, have lower glass transition temperature and wider liquid‐crystalline range, and the BF4− and PF6− even can make the glass transition temperature drop to more than 10°. The polymers exhibit liquid crystal properties only during temperature rising, the quaternary phosphonium ions–containing main‐chain ionic liquid‐crystalline polymers show smectic A phase, and the main‐chain liquid‐crystalline polymers show chiral nematic mesophases. The ionic liquid‐crystalline polymers with phosphorus cations show good bactericidal performance, but the anion has no effect on bactericidal properties.