bluuebunny/crossref_metadata_2025 huggingface dataset:
Removal of Cu(II) ions from aqueous solutions by an ion‐exchange process: Modeling and optimization
Authors: Bleotu Irina , Dragoi Elena Niculina , Mureşeanu Mihaela , Dorneanu Sorin‐Aurel
Published: November 2017

In this paper, an optimal artificial neural network determined by a self‐adaptive differential evolution approach is applied to model and optimize the removal of copper from wastewater by an ion‐exchange process. The Purolite S930+ resin with iminodiacetic group was used in batch mode for Cu(II) removal from synthetic aqueous solutions in different working conditions (initial solution pH, stirring rate, initial concentration of copper, temperature, contact time and resin amount). The obtained results indicated that the used methodology was able to provide good models for the studied process, the mean squared error in the testing phase obtained by the best network being 0.0034. In addition, the optimal combination of parameters leading to the maximization of removal efficiency determined with the proposed approach was experimentally validated, the prediction being in correlation with the observed data. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 605–612, 2018
Application of polynomial chaos theory as an accurate and computationally efficient proxy model for heterogeneous steam‐assisted gravity drainage reservoirs
Authors: Jain Tarang , Patel Rajan G. , Trivedi Japan
Published: November 2017

Reservoir modeling and simulation have become important elements of reservoir management. However, high computational cost associated with the use of numerical simulators make them cumbersome, especially with large‐scale simulation models and complex oil recovery processes like steam‐assisted gravity drainage (SAGD). A data‐driven proxy model can be an alternative to predict SAGD recovery performance in real heterogeneous reservoirs, however, computationally efficient proxy model which can handle large number of input variables while providing accurate results requires further attention. In this work, a proxy model based on polynomial chaos expansion (PCE) is developed to predict the production parameters of SAGD reservoir. Karhunen–Loeve (KL) expansion is used to parameterize input variables in terms of random variables using which PCE further calculates production data for the given reservoir. To calculate coefficients of PCE, probabilistic collocation method is used. To demonstrate the functionality of the proposed approach, case study of a SAGD reservoir located in northern Alberta, Canada is shown in this paper. Various production parameters predicted from the PCE proxy model are compared with the actual simulation results and other proxy models based on radial basis functions (RBF) and artificial neural networks (ANN). From the results, it can be said that PCE proxy model demonstrates good agreement with full‐physics simulation results and outperforms other proxy methods in terms of training data required and accuracy of predictions. In addition, since proposed PCE proxy model greatly reduces the computing cost, it potentially paves the way for expedited and frequent execution of uncertainty quantification, assisted history matching, and optimization workflows, resulting into efficient reservoir management and significant monetary benefits.
An Investigation of PEFC Sub‐Zero Startup: Influence of Initial Conditions and Residual Water
Authors: Stahl P. , Biesdorf J. , Boillat P. , Friedrich K. A.
Published: November 2017

Isothermal cold starts of polymer electrolyte fuel cells were performed at sub‐zero temperatures and analyzed by means of neutron radiography in order to unravel the relation between the preconditioning of the cell and the cold start capability. It was found out that the initial humidification state of the membrane (determined by its resistance) has a clear correlation with the duration of the initial phase of the cold start, but not with the total duration of startup until cell failure. In the experimental setup the impact of realistic and commercial sealing solutions was taken into account by adding an edge channel. The impact of water accumulations in this region on the cold start capability was assessed. Liquid water located in the outer perimeter of a cell could be directly verified to freeze during cell cool down by a novel dual spectrum neutron radiography method. The amount of water accumulated in the outer cell perimeter showed some correlation with the total duration of the cold start. It was found out that residual water located in the edge channel can initiate freezing of a substantial part of the active area nearby.
Tau PET imaging predicts cognition in atypical variants of Alzheimer's disease
Authors: Phillips Jeffrey S. , Das Sandhitsu R. , McMillan Corey T. , Irwin David J. , Roll Emily E. , Da Re Fulvio , Nasrallah Ilya M. , Wolk David A. , Grossman Murray
Published: November 2017

Accumulation of paired helical filament tau contributes to neurodegeneration in Alzheimer's disease (AD). 18F‐flortaucipir is a positron emission tomography (PET) radioligand sensitive to tau in AD, but its clinical utility will depend in part on its ability to predict cognitive symptoms in diverse dementia phenotypes associated with selective, regional uptake. We examined associations between 18F‐flortaucipir and cognition in 14 mildly‐impaired patients (12 with cerebrospinal fluid analytes consistent with AD pathology) who had amnestic (n = 5) and non‐amnestic AD syndromes, including posterior cortical atrophy (PCA, n = 5) and logopenic‐variant primary progressive aphasia (lvPPA, n = 4). Amnestic AD patients had deficits in memory; lvPPA in language; and both amnestic AD and PCA patients in visuospatial function. Associations with cognition were tested using sparse regression and compared to associations in anatomical regions‐of‐interest (ROIs). 18F‐flortaucipir uptake was expected to show regionally‐specific correlations with each domain. In multivariate analyses, uptake was elevated in neocortical areas specifically associated with amnestic and non‐amnestic syndromes. Uptake in left anterior superior temporal gyrus accounted for 67% of the variance in language performance. Uptake in right lingual gyrus predicted 85% of the variance in visuospatial performance. Memory was predicted by uptake in right fusiform gyrus and cuneus as well as a cluster comprising right anterior hippocampus and amygdala; this eigenvector explained 57% of the variance in patients' scores. These results provide converging evidence for associations between 18F‐flortaucipir uptake, tau pathology, and patients' cognitive symptoms.
Estimating the opportunity costs of bed‐days
Authors: Sandmann Frank G. , Robotham Julie V. , Deeny Sarah R. , Edmunds W. John , Jit Mark
Published: November 2017

Opportunity costs of bed‐days are fundamental to understanding the value of healthcare systems. They greatly influence burden of disease estimations and economic evaluations involving stays in healthcare facilities. However, different estimation techniques employ assumptions that differ crucially in whether to consider the value of the second‐best alternative use forgone, of any available alternative use, or the value of the actually chosen alternative. Informed by economic theory, this paper provides a taxonomic framework of methodologies for estimating the opportunity costs of resources. This taxonomy is then applied to bed‐days by classifying existing approaches accordingly. We highlight differences in valuation between approaches and the perspective adopted, and we use our framework to appraise the assumptions and biases underlying the standard approaches that have been widely adopted mostly unquestioned in the past, such as the conventional use of reference costs and administrative accounting data. Drawing on these findings, we present a novel approach for estimating the opportunity costs of bed‐days in terms of health forgone for the second‐best patient, but expressed monetarily. This alternative approach effectively re‐connects to the concept of choice and explicitly considers net benefits. It is broadly applicable across settings and for other resources besides bed‐days.
Human immunodeficiency virus and liver disease: A comprehensive update
Authors: Sherman Kenneth E. , Peters Marion G. , Thomas David
Published: November 2017

Among persons living with human immunodeficiency virus (HIV) infection, liver disease remains a major cause of morbidity and mortality. While the etiologies are varied and often overlapping in the individual patient, the underlying mechanisms, including oxidative stress, direct activation of stellate cells, HIV interaction with hepatocytes, and bacterial translocation with systemic immune activation, seem to be unifying characteristics. Early and fully suppressive HIV antiretroviral therapy is a mainstay of management either before or concurrent with treatment of etiologic cofactors, including hepatitis C virus, hepatitis B virus, and nonalcoholic fatty liver disease/nonalcoholic steatohepatitis. Significant barriers to care that still exist include liver disease recognition, appropriate linkage to care, ongoing substance abuse, and psychiatric comorbidities in the HIV‐infected population. Emerging issues in these patients include acute and chronic hepatitis E, underreported hepatitis D, and a rising incidence of hepatocellular carcinoma. (Hepatology Communications 2017;1:987–1001)
HBV reactivation in allogeneic stem cell transplant recipients: Risk factors, outcome, and role of hepatitis B virus mutations
Authors: Anastasiou Olympia E. , Almpani Foteini , Herrmann Anke , Gerken Guido , Ditschkowski Markus , Ciesek Sandra
Published: November 2017

Hepatitis B virus (HBV) reactivation (HBVr) in recipients of allogeneic hematopoetic stem cells (aHSCs) appears heterogeneously with respect to its frequency, manifestation, and outcome. The aim of this study was to present data from a large German cohort of recipients of aHSC transplantation (aHSCT), focusing on the incidence of HBVr in antibody to hepatitis B core antigen (anti‐HBc)‐positive aHSCT recipients, its clinical outcome, and the role of mutations in HBV. Between 2005 and 2015, 1,871 patients received aHSCT at University Hospital Essen. A follow‐up of at least 6 months after transplant was available in 55 patients who were anti‐HBc‐positive; clinical and virologic data were analyzed. The HBV genome was sequenced with next generation technology from serum samples of 8 patients with HBVr. Thirteen out of 55 (23.6%) patients developed HBVr at a median of 26 months after aHSCT. After initiation of antiviral treatment, complete HBV DNA suppression was achieved in 7/10 (70%) patients 1 to 40 months after HBVr. Nine of 13 patients had increased alanine aminotransferase; 3 patients had compromised coagulation and model for end‐stage liver disease scores of 18‐27, and 1 of these patients died due to liver failure 5 weeks after HBVr. As a risk factor for HBVr, we identified anti‐HBc signal to cut‐off ration (S/CO) ≥7.5 before transplantation. Complete HBV DNA suppression was achieved in 7/10 patients; therapy‐relevant mutations were found in 1 patient. In 4/8 patients, immune escape mutations were detected either as majority or minority variants. Conclusion: HBVr is common in anti‐HBc‐positive aHRCT recipients and can lead to severe hepatitis with compromised coagulation. The level of anti‐HBc S/CO before transplantation is a risk factor for HBVr. Complete virologic response under adequate antiviral treatment could not be achieved in all patients. (Hepatology Communications 2017;1:1014–1023)
Bioinspired Synthesis of Lepidocrocite‐Containing Material and Its Catalytic Behaviour in CO Oxidation
Authors: Shopska Maya G. , Paneva Daniela G. , Kolev Hristo G. , Kadinov Georgi B. , Ilieva Ralitsa , Iliev Mihail , Cherkezova‐Zheleva Zara P. , Mitov Ivan G.
Published: November 2017

Leptothrix sp. was cultivated in Lieske's medium in the presence of Al foil covered by anodic Alumina. Samples of biomass deposited on lamellae were studied by the methods of infrared, Mössbauer, and X‐ray photoelectron spectroscopy. Sole deposition of γ‐FeOOH on the lamellae was found to take place. This result is explained by the influence of γ‐AlOOH ingredient in the used support due to crystal structure similarity. Thus, iron oxyhydroxide crystallisation could be directed during bacteria cultivation. The catalytic activity of deposited γ‐FeOOH was examined in CO oxidation.
Worse than others but better than before: Integrating social and temporal comparison perspectives to explain executive turnover via pay standing and pay growth
Authors: Tröster Christian , Van Quaquebeke Niels , Aquino Karl
Published: November 2017

Organizations often pay greater salaries to higher‐ranking executives compared to lower‐ranking executives. While this method can be useful for retaining those at the organization's apex, it may also incline executives at the bottom of the pay pyramid to see themselves at a disadvantage and thus exit the firm. Naturally, organizations often want to retain some of their lower‐paid, but highly valuable executives; the question, then, is how organizations can reduce the turnover of lower‐ranking executives. By integrating social with temporal comparison theory, we argue that, when executives earn relatively less than their peers, more pay growth (i.e., individual pay increases over time) leads to less turnover. The results of our analysis, which covered almost 20 years of objective data on a large sample of U.S. top executives, provide support for our theory.
The effect of temporal manipulation of transforming growth factor beta 3 and fibroblast growth factor 2 on the derivation of proliferative chondrocytes from mensenchymal stem cells—A study monitored by quantitative reverse transcription polymerase chain reaction and molecular beacon based nanosensors
Authors: Tay Li Min , Wiraja Christian , Wu Yingnan , Yang Zheng , Lee Eng Hin , Xu Chenjie
Published: November 2017

Proliferative chondrocytes are critical to realize regeneration of damaged epiphyseal growth plate. However, acquiring autologous replacement cells involves highly invasive procedures and often results in limited cell quantity. Mesenchymal stem cells (MSCs) are a potential source of chondrogenic cells for the treatment of cartilage disorders and injuries. The temporal effect of transforming growth factor beta 3 (TGFβ3) and fibroblast growth factor 2 (FGF2) on the derivation of proliferative chondrocytes from MSCs in three‐dimensional agarose was investigated by manipulating the duration of TGFβ3 and FGF2 treatment. The differentiation process was monitored by quantitative reverse transcription polymerase chain reaction (qRT‐PCR) as well as nanosensors containing two molecular beacons that target critical biomarkers for proliferative chondrocytes (i.e., collagen type‐II messenger ribonucleic acid [mRNA] and Ki67 mRNA). The molecular beacon‐based nanosensors were found to be comparable to qRT‐PCR in measuring mRNA expression and thus providing a noninvasive mean to screen and monitor culture samples. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 895–904, 2018.
Characterization of printed PLA scaffolds for bone tissue engineering
Authors: Grémare Agathe , Guduric Vera , Bareille Reine , Heroguez Valérie , Latour Simon , L'heureux Nicolas , Fricain Jean‐Christophe , Catros Sylvain , Le Nihouannen Damien
Published: November 2017

Autografts remain the gold standard for orthopedic transplantations. However, to overcome its limitations, bone tissue engineering proposes new strategies. This includes the development of new biomaterials such as synthetic polymers, to serve as scaffold for tissue production. The objective of this present study was to produce poly(lactic) acid (PLA) scaffolds of different pore size using fused deposition modeling (FDM) technique and to evaluate their physicochemical and biological properties. Structural, chemical, mechanical, and biological characterizations were performed. We successfully fabricated scaffolds of three different pore sizes. However, the pore dimensions were slightly smaller than expected. We found that the 3D printing process induced decreases in both, PLA molecular weight and degradation temperatures, but did not change the semicrystalline structure of the polymer. We did not observe any effect of pore size on the mechanical properties of produced scaffolds. After the sterilization by γ irradiation, scaffolds did not exhibit any cytotoxicity towards human bone marrow stromal cells (HBMSC). Finally, after three and seven days of culture, HBMSC showed high viability and homogenous distribution irrespective of pore size. Thus, these results suggest that FDM technology is a fast and reproducible technique that can be used to fabricate tridimensional custom‐made scaffolds for tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 887–894, 2018.
Evaluation of central venous catheters coated with a noble metal alloy—A randomized clinical pilot study of coating durability, performance and tolerability
Authors: Björling Gunilla , Johansson Dorota , Bergström Linda , Strekalovsky Anton , Sanchez Javier , Frostell Claes , Kalman Sigridur
Published: November 2017

The use of Central Venous Catheters (CVCs) commonly results in complications. Coatings with silver or metal alloys can reduce the risk associated with the use of CVC. We have evaluated the durability of a noble metal coated CVC (the Bactiguard Infectious Protection, BIP CVC) and compared with an uncoated CVC for clinical tolerability (Adverse Events, AEs) and performance, in order to create a baseline for a large future study. Patients undergoing major surgery, randomised at a 2:1 ratio to BIP CVC (n = 22) or standard CVC (n = 12), were catheterized 9 ‐ 12 days, respectively. Adverse events, microbial colonization and metal release were measured.

Findings: There were no AEs in the BIP CVC‐group, but 5 AEs occurred in 4 patients (1 patient had 2 AEs) in the standard CVC‐group, p = 0.011 (whereof 3 were catheter related). The BIP CVC showed an initial release of coating metals in blood (gold, silver and palladium), which rapidly decreased and were far below Permitted Paily Exposure (PDE) for chronical use. The levels of silver concentration were far below those needed to develop microbial resistance. The performance was equal, and there was no difference concerning microbial colonization, for the two CVCs.

Conclusion: In this pilot study the BIP CVC had significantly lower AEs and showed a comparable performance to the standard CVC. The coating was durable throughout the study length (up to 16 days) and toxicological evaluation showed good safety margins. Larger studies are needed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2337–2344, 2018.
Hyaluronic acid in the tail and limb of amphibians and lizards recreates permissive embryonic conditions for regeneration due to its hygroscopic and immunosuppressive properties
Authors: Alibardi Lorenzo
Published: November 2017

The present review focuses on the role of hyaluronate (hyaluronic acid; HA) during limb and tail regeneration in amphibians and lizards mainly in relation to cells of the immune system. This non‐sulfated glycosaminoglycan (GAG) increases in early stages of wound healing and blastema formation, like during limb or tail embryogenesis, when the immune system is still immature. The formation of a regenerating blastema occurs by the accumulation of mesenchymal cells displaying embryonic‐like antigens and HA. This GAG adsorbs large amount of water and generates a soft tissue over 80% hydrated where mesenchymal and epithelial cells can move and interact, an obligatory passage for organ regeneration. GAGs and HA in particular rise to a high amount and coat plasma membranes of blastema cells forming a shield that likely impedes to the circulating immune cells to elicit an immune reaction against the embryonic‐like antigens present on blastema cells. The evolution of limb–tail regeneration in amphibians dates back to the Devonian‐Carboniferous, while tail regeneration in lizards is a more recent evolution process, possibly occurred since the Jurassic, which is unique among amniotes. Both processes are associated with the reactivation of proliferating embryonic programs that involve the upregulation of genes for Wnt, non‐coding RNAs, and HA synthesis in an immune‐suppress organ, the regenerative blastema. Failure of maintaining a lasting HA synthesis for the formation of a highly hydrated blastema leads to scarring, the common healing process of amniotes equipped with an efficient immune system. The study of amphibian and lizard regeneration indicates that attempts to stimulate organ regeneration in other vertebrates require the induction of a highly hydrated and immune‐depressed, HA‐rich environment, similar to the extracellular environment present during development.
Co‐delivery of hypoxia inducible factor‐1α small interfering RNA and 5‐fluorouracil to overcome drug resistance in gastric cancer SGC‐7901 cells
Authors: Chen Yunna , Sun Li , Guo Dongdong , Wu Ziteng , Chen Weidong
Published: November 2017

Background

Drug resistance cancer cells have become a major problem in chemotherapy. To solve this problem, the co‐delivery of small interefering RNA (siRNA) and 5‐fluorouracil chitosan nanoparticles was employed, aiming to reverse the multidrug resistance of gastric cancer SGC‐7901 cells in vitro.

Methods

Chitosan nanoparticles were prepared using an ionic gel method. siRNA nanoparticles were characterized by gel retardation assays. Particle size and zeta potential were measured to confirm nanoparticle formation. The transfection efficiency of siRNA was determined by flow cytometry and high‐content screening. Western blotting and a quantitative real‐time‐polymerase chain reaction were used to assess the silencing efficiency of siRNA. Accumulation and efflux experiments for rhodamine‐123, cell migration experiments, cell sensitivity analyses and cell apoptosis assays were used to determine whether siRNA could reverse multidrug resistance. A systemic toxicity assay was used to evaluate the safety of nanoparticles.

Results

Compared to naked siRNA, the co‐delivery system demonstrated a higher transfection efficiency and gene silencing efficiency by inhibiting the efflux of P‐glycoprotein and cell migration. Moreover, the combination treatment with siRNA and 5‐fluorouracil co‐delivered by chitosan nanoparticles can increase the sensitivity of drug resistance cells and cell apoptosis. Finally, the safety of nanoparticles was evaluated in vivo and the results obtained suggested that nanoparticles did not have any obvious toxicity.

Conclusions

Co‐delivery of siRNA and 5‐fluorouracil chitosan nanoparticles is an attractive strategy for overcoming multidrug resistance.
Toxicity effects of AgZnO nanoparticles and rifampicin on Mycobacterium tuberculosis into the macrophage
Authors: Jafari Alireza , Jafari Nodooshan Saeedeh , Safarkar Roya , Movahedzadeh Farahnaz , Mosavari Nader , Novin Kashani Aren , Dehghanpour Mahdi , Kamalzadeh Morteza , Rasouli Koohi Samira , Fathizadeh Sara , Majidpour Ali
Published: November 2017

The World Health Organization acknowledges tuberculosis as a global threat. Tuberculosis infection is one of the top 10 causes of death worldwide. Nanotechnology and microbiology researchers are looking for new and safe nano drugs for eliminating Mycobacterium tuberculosis, the causative agent of tuberculosis. In this study, AgZnO nano‐crystals (AgZnONCs) is synthesized via the decomposition of the precursor of oxalate method. Characterization of AgZnONCs were evaluated. Next, various concentrations of AgZnONCs, as well AgZnONCs+Rifampicin, were prepared. The MTT assay was employed to study the viability of human macrophage cell lines (THP‐1) exposed to AgZnONCs. The bactericidal effects of AgZnONCs and AgZnONCs+Rifampicin were studied by Minimum Bactericidal Concentration (MBC) test. Subsequently, THP‐1 were infected by H37Rv strain of M. tuberculosis (H37RvMtb). Also, bactericidal effects of AgZnONCs and AgZnONCs+Rifampicin were compared with ex‐vivo conditions. The MBC of AgZnONCs and AgZnONCs+Rifampicin were ratios of 1:4 and 1:32 respectively (p‐value <0.05). Also, more than 50% and 80% of THP‐1 were alive in ratios of 1:4 and 1:32 in the presence of AgZnONCs, respectively. All phagocytic H37RvMtb were killed in the presence of AgZnONCs+Rifampicin (p‐value <0.05), while AgZnONCs were not able to kill all the H37RvMtb (p‐value >0.05). This study showed that, AgZnONCs+Rifampicin has the most anti‐tubercular behavior with respect to the macrophages.
Preharvest treatments with salicylates enhance nutrient and antioxidant compounds in plum at harvest and after storage
Authors: Martínez‐Esplá Alejandra , Zapata Pedro J , Valero Daniel , Martínez‐Romero Domingo , Díaz‐Mula Huertas M , Serrano María
Published: November 2017

BACKGROUND

Previous reports have addressed the effectiveness of salicylic acid (SA), acetylsalicylic acid (ASA) and methylsalicylate (MeSA) postharvest treatments on maintaining quality properties during storage in several commodities. However, there is no literature regarding the effect of preharvest treatments with salicylates on plum quality attributes (at harvest or after long‐term cold storage), which was evaluated in this research.

RESULTS

At harvest, weight, firmness, individual organic acids, sugars, phenolics, anthocyanins and total carotenoids were found at higher levels in plums from SA‐, ASA‐ and MeSA‐treated trees than in those from controls. During storage, softening, colour changes and acidity losses were delayed in treated fruits as compared to controls. In addition, organic acids and antioxidant compounds were still found at higher levels in treated than in control plums after 40 days of storage. Results show a delay in the postharvest ripening process due to salicylate treatments, which could be attributed to their effect in delaying and decreasing ethylene production.

CONCLUSION

Preharvest treatment with salicylates could be a safety, eco‐friendly and new tool to improve (at harvest) and maintain (during storage) plum quality and especially its content of bioactive compounds with antioxidant properties, increasing the health effects of plum consumption. © 2017 Society of Chemical Industry
Recovery and stability over time of phenolic fractions by an industrial filtration system of olive mill wastewaters: a three‐year study
Authors: Bellumori Maria , Cecchi Lorenzo , Romani Annalisa , Mulinacci Nadia , Innocenti Marzia
Published: November 2017

BACKGROUND

The recovery of phenolic compounds from olive milling is recognized as strategic for producers. The aim of this work was to evaluate the quality and stability of retentates obtained from olive mill wastewaters treated with a membrane filtration system constituted by a micro‐, ultra‐ and nanofiltration, followed by a final reverse osmosis, over three crop seasons. Efficiency was evaluated in terms of phenolic amount in the retentates and of organic load in the final discarded waters. Phenolic compounds were quantified using tyrosol as external standard.

RESULTS

Our study highlighted a reproducibility of the process over years and a low organic load in permeates from reverse osmosis. Hydroxytyrosol was very stable in the liquid products at 18–28 °C over 24 months of storage. The retentates from reverse osmosis showed the highest phenolic content (78.6 mg g−1 dry matter in 2015), associated with a potassium content of 22 g kg−1.

CONCLUSIONS

The liquid concentrated retentates showed an unexpected stability over time of their bioactive phenolic compounds, particularly of hydroxytyrosol. These samples recovered from olive mill wastewaters can be good sources of natural antioxidants and potassium to guarantee the correct intake and to formulate new food ingredients or food products. © 2017 Society of Chemical Industry
Identification of Salvia species using high‐performance liquid chromatography combined with chemical pattern recognition analysis
Authors: Wang Yang , Jiang Kun , Wang Lijun , Han Dongqi , Yin Guo , Wang Jue , Qin Bin , Li Shaoping , Wang Tiejie
Published: November 2017

Salvia miltiorrhiza, also known as Danshen, is a widely used traditional Chinese medicine for the treatment of cardiovascular diseases and hematological abnormalities. The root and rhizome of Salvia przewalskii and Salvia yunnanensis have been found as substitutes for Salvia miltiorrhiza in the market. In this study, the chemical information of 14 major compounds in Salvia miltiorrhiza and its substitutes were determined using a high‐performance liquid chromatography method. Stepwise discriminant analysis was adopted to select the characteristic variables. Partial least squares discriminant and hierarchical cluster analysis were performed to classify Salvia miltiorrhiza and its substitutes. The results showed that all of the samples were correctly classified both in partial least squares discriminant analysis and hierarchical cluster analysis based on the four compounds (caffeic acid, rosmarinic acid, salvianolic acid B, and salvianolic acid A). This method can not only distinguish Salvia miltiorrhiza and its substitutes, but also classify Salvia przewalskii and Salvia yunnanensis. The method can be applied for the quality assessment of Salvia miltiorrhiza and identification of unknown samples.
Pediatric tinnitus: A clinical perspective
Authors: Chan Kenny H. , Jensen Emily L. , Gao Dexiang
Published: November 2017

Objectives/Hypothesis

To define the clinical features and natural history of pediatric tinnitus from a practicing otolaryngologist's perspective and formulate hypotheses therein.

Study Design

Retrospective chart review.

Methods

A retrospective chart review of the electronic medical record was undertaken. Only relevant records with a prior otolaryngology clinic visit and audiologic testing were included. Patients seen during the last 2 years of the study period were contacted and completed a questionnaire to assess change in tinnitus and quantify potential alterations in quality of life, associated symptoms, and natural history.

Results

One hundred eighty subjects with mean/median age of 11.5/11.5 years were identified. Hearing loss was identified in 40 subjects (22.2%). Etiology of tinnitus was identified in 95 subjects (52.8 %). Tinnitus‐specific and/or nonspecific therapies were given to 80 subjects (44.4%). Of the 54 available subjects, 28 (51.9%) participated in the telephone questionnaire. Tinnitus complaints shifted favorably to the improvement or resolution categories (P = .001) between the initial clinic visit and the telephone interview. Shorter duration of tinnitus was associated with a higher probability of having improved tinnitus (P = .046).

Conclusions

This study distinguishes pediatric tinnitus from adult tinnitus in terms of lower association with underlying hearing loss, lower likelihood of reported anxiety, and higher likelihood of improvement and resolution. There are opportunities for tinnitus prevention in the areas of reducing head injury and noise‐induced hearing loss.

Level of Evidence

4. Laryngoscope, 128:727–731, 2018
In Silico Studies of Mammalian δ‐ALAD Interactions with Selenides and Selenoxides
Authors: Andrei Nogara Pablo , Batista Teixeira Rocha João
Published: November 2017

Previous studies have shown that the mammalian δ‐aminolevulinic acid dehydratase (δ‐ALAD) is inhibited by selenides and selenoxides, which can involve thiol oxidation. However, the precise molecular interaction of selenides and selenoxides with the active center of the enzyme is unknown. Here, we try to explain the interaction of selenides and the respective selenoxides with human δ‐ALAD by in silico molecular docking. The in silico data indicated that Se atoms of selenoxides have higher electrophilic character than their respective selenides. Further, the presence of oxygen increased the interaction of selenoxides with the δ‐ALAD active site by O…Zn coordination. The interaction of S atom from Cys124 with the Se atom indicated the importance of the nucleophilic attack of the enzyme thiolate to the organoselenium molecules. These observations help us to understand the interaction of target proteins with organoselenium compounds.
Surface applicator of a miniature X‐ray tube for superficial electronic brachytherapy of skin cancer
Authors: Kim Hyun Nam , Lee Ju Hyuk , Park Han Beom , Kim Hyun Jin , Cho Sung Oh
Published: November 2017

Purpose

We designed and fabricated a surface applicator of a novel carbon nanotube (CNT)‐based miniature X‐ray tube for the use in superficial electronic brachytherapy of skin cancer. To investigate the effectiveness of the surface applicator, the performance of the applicator was numerically and experimentally analyzed.

Methods

The surface applicator consists of a graphite flattening filter and an X‐ray shield. A Monte Carlo radiation transport code,MCNP6, was used to optimize the geometries of both the flattening filter and the shield so that X‐rays are generated uniformly over the desired region. The performance of the graphite filter was compared with that of conventional aluminum (Al) filters of different geometries using the numerical simulations. After fabricating a surface applicator, the X‐ray spatial distribution was measured to evaluate the performance of the applicator.

Results

The graphite filter shows better spatial dose uniformity and less dose distortion than Al filters. Moreover, graphite allows easy fabrication of the flattening filter due to its low X‐ray attenuation property, which is particularly important for low‐energy electronic brachytherapy. The applicator also shows that no further X‐ray shielding is required for the application because unwanted X‐rays are completely protected. As a result, highly uniform X‐ray dose distribution was achieved from the miniature X‐ray tube mounted with the surface applicators. The measured values of both flatness and symmetry were less than 5% and the measured penumbra values were less than 1 mm. All these values satisfy the currently accepted tolerance criteria for radiation therapy.

Conclusions

The surface applicator exhibits sufficient performance capability for their application in electronic brachytherapy of skin cancers.
Fast, Na+/K+ pump driven, steady‐state transcytolemmal water exchange in neuronal tissue: A study of rat brain cortical cultures
Authors: Bai Ruiliang , Springer Charles S. , Plenz Dietmar , Basser Peter J.
Published: November 2017

Purpose

Water homeostasis and transport play important roles in brain function (e.g., ion homeostasis, neuronal excitability, cell volume regulation, etc.). However, specific mechanisms of water transport across cell membranes in neuronal tissue have not been completely elaborated.

Methods

The kinetics of transcytolemmal water exchange were measured in neuronal tissue using simultaneous, real‐time fluorescence and nuclear magnetic resonance (NMR) measurements of perfused, active brain organotypic cortical cultures. Perfusion with a paramagnetic MRI contrast agent, gadoteridol, allows NMR determination of the unidirectional rate constant for steady‐state cellular water efflux (kio), and the mole fraction of intracellular water (
), related to the average cell volume (V). Changes in intracellular calcium concentration
were used as a proxy for neuronal activity and were monitored by fluorescence imaging.

Results

The kio value, averaged over all cultures (N = 99) at baseline, was 2.02 (±1.72) s−1, indicating that on average, the equivalent of the entire intracellular water volume turns over twice each second. To probe possible molecular pathways, the specific Na+‐K+‐ATPase (NKA) inhibitor, ouabain (1 mM), was transiently introduced into the perfusate. This caused significant transient changes (N = 8):
rose ∼250%,
rose ∼89%, and kio fell ∼45%, with a metabolically active kio contribution probably eliminated by ouabain saturation.

Conclusions

These results suggest that transcytolemmal water exchange in neuronal tissue involves mechanisms affected by NKA activity as well as passive pathways. The active pathway may account for half of the basal homeostatic water flux. Magn Reson Med 79:3207–3217, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Density‐weighted concentric circle trajectories for high resolution brain magnetic resonance spectroscopic imaging at 7T
Authors: Hingerl Lukas , Bogner Wolfgang , Moser Philipp , Považan Michal , Hangel Gilbert , Heckova Eva , Gruber Stephan , Trattnig Siegfried , Strasser Bernhard
Published: November 2017

Purpose

Full‐slice magnetic resonance spectroscopic imaging at
T is especially vulnerable to lipid contaminations arising from regions close to the skull. This contamination can be mitigated by improving the point spread function via higher spatial resolution sampling and k‐space filtering, but this prolongs scan times and reduces the signal‐to‐noise ratio (SNR) efficiency. Currently applied parallel imaging methods accelerate magnetic resonance spectroscopic imaging scans at 7T, but increase lipid artifacts and lower SNR‐efficiency further. In this study, we propose an SNR‐efficient spatial‐spectral sampling scheme using concentric circle echo planar trajectories (CONCEPT), which was adapted to intrinsically acquire a Hamming‐weighted k‐space, thus termed density‐weighted‐CONCEPT. This minimizes voxel bleeding, while preserving an optimal SNR.

Theory and Methods

Trajectories were theoretically derived and verified in phantoms as well as in the human brain via measurements of five volunteers (single‐slice, field‐of‐view 220 × 220 mm2, matrix 64 × 64, scan time 6 min) with free induction decay magnetic resonance spectroscopic imaging. Density‐weighted‐CONCEPT was compared to (a) the originally proposed CONCEPT with equidistant circles (here termed e‐CONCEPT), (b) elliptical phase‐encoding, and (c) 5‐fold Controlled Aliasing In Parallel Imaging Results IN Higher Acceleration accelerated elliptical phase‐encoding.

Results

By intrinsically sampling a Hamming‐weighted k‐space, density‐weighted‐CONCEPT removed Gibbs‐ringing artifacts and had in vivo +9.5%, +24.4%, and +39.7% higher SNR than e‐CONCEPT, elliptical phase‐encoding, and the Controlled Aliasing In Parallel Imaging Results IN Higher Acceleration accelerated elliptical phase‐encoding (all P < 0.05), respectively, which lead to improved metabolic maps.

Conclusion

Density‐weighted‐CONCEPT provides clinically attractive full‐slice high‐resolution magnetic resonance spectroscopic imaging with optimal SNR at 7T. Magn Reson Med 79:2874–2885, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Relative identifiability of anisotropic properties from magnetic resonance elastography
Authors: Miller Renee , Kolipaka Arunark , Nash Martyn P. , Young Alistair A.
Published: November 2017

Although magnetic resonance elastography (MRE) has been used to estimate isotropic stiffness in the heart, myocardium is known to have anisotropic properties. This study investigated the determinability of global transversely isotropic material parameters using MRE and finite‐element modeling (FEM). A FEM‐based material parameter identification method, using a displacement‐matching objective function, was evaluated in a gel phantom and simulations of a left ventricular (LV) geometry with a histology‐derived fiber field. Material parameter estimation was performed in the presence of Gaussian noise. Parameter sweeps were analyzed and characteristics of the Hessian matrix at the optimal solution were used to evaluate the determinability of each constitutive parameter. Four out of five material stiffness parameters (Young's modulii E1 and E3, shear modulus G13 and damping coefficient s), which describe a transversely isotropic linear elastic material, were well determined from the MRE displacement field using an iterative FEM inversion method. However, the remaining parameter, Poisson's ratio, was less identifiable. In conclusion, Young's modulii, shear modulii and damping can theoretically be well determined from MRE data, but Poisson's ratio is not as well determined and could be set to a reasonable value for biological tissue (close to 0.5).
Booter list generation: The basis for investigating DDoS‐for‐hire websites
Authors: Santanna José Jair , de Vries Joey , de O. Schmidt Ricardo , Tuncer Daphne , Z. Granville Lisandro , Pras Aiko
Published: November 2017

The expansion of Distributed Denial of Service (DDoS)–for‐hire websites, known as Booters, has radically modified both the scope and stakes of DDoS attacks. Until recently, however, Booters have only received little attention from the research community. Given their impact, addressing the challenges associated with this phenomenon is crucial. In this paper, we present a rigorous methodology to identify a comprehensive set of existing Booters in the Internet. Before presenting our methodology, we illustrate the benefits of a set of booters on monitoring users from the Dutch NREN, SURFNet, from 2015 to 2017. Our methodology relies on well‐defined mechanisms to generate a Booter list, from crawling suspect URLs to characterizing and classifying the collected URLs. The list obtained using the methodology presented in this paper has a classification accuracy of 95.5%, which is 10.5% better compared to previous work.
Paid Family Leave, Fathers’ Leave‐Taking, and Leave‐Sharing in Dual‐Earner Households
Authors: Bartel Ann P. , Rossin‐Slater Maya , Ruhm Christopher J. , Stearns Jenna , Waldfogel Jane
Published: November 2017

Using difference‐in‐difference and difference‐in‐difference‐in‐difference designs, we study California's Paid Family Leave (CA‐PFL) program, the first source of government‐provided paid parental leave available to fathers in the Unites States. Relative to the pre‐treatment mean, fathers of infants in California are 46 percent more likely to be on leave when CA‐PFL is available. In households where both parents work, we find suggestive evidence that CA‐PFL increases both father‐only leave‐taking (i.e., father on leave while mother is at work) and joint leave‐taking (i.e., both parents on leave at the same time). Effects are larger for fathers of first‐born children than for fathers of later‐born children.
Influence of in situ synthesized bismuth oxide nanostructures in self‐poled PVDF‐based nanogenerator for mechanical energy harvesting application
Authors: Biswas Anirban , Garain Samiran , Maity Kuntal , Henkel Karsten , Schmeißer Dieter , Mandal Dipankar
Published: November 2017

A self‐poled piezoelectric nanogenerator (NG) based on bismuth oxide (Bi2O3) nanostructures (BNS)‐doped poly(vinylidene fluoride) (PVDF) is demonstrated. The in‐situ formation of BNS incorporated in the PVDF matrix is realized through a simple solution casting technique that favors the nucleation and stabilization of 99.6% of the electroactive phase in PVDF (i.e., β/γ‐phases). The enhancement of the output voltage (3.6 V) and current (2.4 µA) of the NG based on a nonelectrically poled BNS containing PVDF composite film is achieved and demonstrated by simple repeated human finger imparting. The improvement of the output performance is influenced by the generation of the electroactive polar β‐phase in PVDF, due to the electrostatic interactions between the –CH2–/–CF2– dipoles of PVDF and the surface charge of the BNS. The NGs are able to charge up capacitors demonstrating that the power generation from such a hybrid device structure can be utilized for powering various portable devices. POLYM. COMPOS., 40:E265–E274, 2019. © 2017 Society of Plastics Engineers
Hybrid biocomposites
Authors: Guna Vijaykumar , Ilangovan Manikandan , Ananthaprasad M.G. , Reddy Narendra
Published: November 2017

Composites are primarily made using matrix and reinforcement as major components but may also contain several other fillers or additives. A majority of the composites are made using synthetic fibers and polymers. However, in the last few decades, focus has been on developing biocomposites using renewable resources. Conventionally, biocomposites are developed using natural fibers such as jute, Kenaf, or Ramie as reinforcement and synthetic resins such as polyethylene, polypropylene and epoxy as matrix. Typically, biocomposites contain either the reinforcement or matrix which makes the composites partially degradable. Such partially degradable composites provide good properties, but the presence of a nonbiodegradable component, particularly as a matrix limits their biodegradability. Alternatively, composites that contain both the matrix and reinforcement from renewable resources which make the composites completely degradable have also been developed. However, these completely biodegradablebiocomposites do not have the desired mechanical properties and stability at high humidities or in aqueous environments which restricts their application. In addition, natural fibers and resins used in biocomposites have inherent limitations and also not easily processable. To overcome limitation of using a single reinforcement or matrix derived from bioresources, hybrid composites that contain more than one reinforcement or matrix are developed. Such hybrid composites are manufactured by either intimately mixing two or more fibers or other reinforcing materials or by placing different layers of the reinforcement and molding them into composites using one or more resins. Conventionally, hybrid composites refer to metallic and ceramic based reinforcement, matrix and fillers. Although hybrid biocomposites are gaining significant attention, the presence of multiple reinforcements and/or matrix makes it difficult to process and also to predict the properties of such composites. Hence, understanding the properties and potential of using multiple reinforcements and/or matrix materials from renewable resources to develop biobased hybrid composites is highly desirable. This article discusses hybrid composites that contain a major proportion of renewable materials. Hybrid composites not only provide better properties but could also lead to substantial cost reduction due to the incorporation of inexpensive raw materials. These composites show potential for use in aeronautical, sporting goods, wind power turbine blades, helmets and civil construction such as pedestrian bridges and many other applications. This review provides an overview of the biobased materials used to develop hybrid composites, their processability and their potential applications. POLYM. COMPOS., 39:E30–E54, 2018. © 2017 Society of Plastics Engineers