bluuebunny/crossref_metadata_2025 huggingface dataset:
Virtual Consultations Through the Veterans Administration SCAN‐ECHO Project Improves Survival for Veterans With Liver Disease
Authors: Su Grace L. , Glass Lisa , Tapper Elliot B. , Van Tony , Waljee Akbar K. , Sales Anne E.
Published: May 2018

Access to specialty care has been associated with improved survival in patients with liver disease but universal access is not always feasible. Methods of care delivery using virtual modalities including the SCAN‐ECHO (Specialty Access Network‐Extension of Community Healthcare Outcome) program were implemented by the Veterans Health Administration (VHA) to address this need but limited data are available on patient outcomes. We sought to evaluate the efficacy of a SCAN‐ECHO visit within the context of a regional cohort of patients with liver disease in the VHA (n = 62,237) following implementation in the Ann Arbor SCAN‐ECHO Liver Clinic from June 1, 2011, to March 31, 2015. The effect of a SCAN‐ECHO visit on all‐cause mortality was compared with patients with no liver clinic visit. To adjust for the differences among patients who had a SCAN‐ECHO visit versus those with no visit, propensity score matching was performed on condition factors that affect the likelihood of a SCAN‐ECHO visit: demographics, geographic location, liver disease diagnosis, severity, and comorbidities. During the study period, 513 patients who had a liver SCAN‐ECHO visit were found within the cohort. Patients who had completed a virtual SCAN‐ECHO visit were more likely younger, rural, with more significant liver disease, and evidence for cirrhosis. Propensity‐adjusted mortality rates using the Cox Proportional Hazard Model showed that a SCAN‐ECHO visit was associated with a hazard ratio of 0.54 (95% confidence interval 0.36‐0.81, P = 0.003) compared with no visit. Conclusion: Improved survival in patients using SCAN‐ECHO suggests that this approach may be an effective method to improve access for selected patients with liver disease, particularly in rural and underserved populations where access to specialty care is limited.
Ad Libitum Mediterranean and Low‐Fat Diets Both Significantly Reduce Hepatic Steatosis: A Randomized Controlled Trial
Authors: Properzi Catherine , O'Sullivan Therese A. , Sherriff Jill L. , Ching Helena L. , Jeffrey Garry P. , Buckley Rachel F. , Tibballs Jonathan , MacQuillan Gerry C. , Garas George , Adams Leon A.
Published: May 2018

Although diet‐induced weight loss is first‐line treatment for patients with nonalcoholic fatty liver disease (NAFLD), long‐term maintenance is difficult. The optimal diet for improvement in either NAFLD or associated cardiometabolic risk factors, regardless of weight loss, is unknown. We examined the effect of two ad libitum isocaloric diets (Mediterranean [MD] or low fat [LF]) on hepatic steatosis (HS) and cardiometabolic risk factors. Subjects with NAFLD were randomized to a 12‐week blinded dietary intervention (MD vs. LF). HS was determined by magnetic resonance spectroscopy (MRS). From a total of 56 subjects enrolled, 49 completed the intervention and 48 were included for analysis. During the intervention, subjects on the MD had significantly higher total and monounsaturated fat, but lower carbohydrate and sodium, intakes compared to LF subjects (P < 0.01). At week 12, HS had reduced significantly in both groups (P < 0.01), and there was no difference in liver fat reduction between groups (P = 0.32), with mean (SD) relative reductions of 25.0% (±25.3%) in LF and 32.4% (±25.5%) in MD. Liver enzymes also improved significantly in both groups. Weight loss was minimal and not different between groups (–1.6 [±2.1] kg in LF vs –2.1 [±2.5] kg in MD; P = 0.52). Within‐group improvements in Framingham Risk Score (FRS), total cholesterol, serum triglyceride (TG), and glycated hemoglobin (HbA1c) were observed in the MD (all P < 0.05), but not with the LF diet. Adherence was higher for the MD compared to LF (88% vs. 64%; P = 0.048). Conclusion: Ad libitum low‐fat and Mediterranean diets both improve HS to a similar degree.
Potential Clinical Targets in Hepatopulmonary Syndrome: Lessons From Experimental Models
Authors: Raevens Sarah , Fallon Michael B.
Published: May 2018

Hepatopulmonary syndrome (HPS) is a relatively common and potentially severe pulmonary complication of cirrhosis with increased risk of mortality. In experimental models, a complex interaction between pulmonary endothelial cells, monocytes, and the respiratory epithelium, which produces chemokines, cytokines, and angiogenic growth factors, causes alterations in the alveolar microvasculature, resulting in impaired oxygenation. Model systems are critical for evaluating mechanisms and for preclinical testing in HPS, due to the challenges of evaluating the lung in the setting of advanced liver disease in humans. This review provides an overview of current knowledge and recent findings in the rodent common bile duct ligation model of HPS, which recapitulates many features of human disease. We focus on the concepts of endothelial derangement, monocyte infiltration, angiogenesis, and alveolar type II cell dysfunction as main contributors and potential targets for therapy.
An evidence‐based approach to assessing surgical versus clinical diagnosis of symptomatic endometriosis
Authors: Taylor Hugh S. , Adamson G. David , Diamond Michael P. , Goldstein Steven R. , Horne Andrew W. , Missmer Stacey A. , Snabes Michael C. , Surrey Eric , Taylor Robert N.
Published: May 2018

Challenges intrinsic to the accurate diagnosis of endometriosis contribute to an extended delay between the onset of symptoms and clinical confirmation. Intraoperative visualization, preferably with histologic verification, is considered by many professional organizations to be the gold standard by which endometriosis is diagnosed. Clinical diagnosis of symptomatic endometriosis via patient history, physical examination, and noninvasive tests, though more easily executed, is generally viewed as less accurate than surgical diagnosis. Technological advances and increased understanding of the pathophysiology of endometriosis warrant continuing reevaluation of the standard method for diagnosing symptomatic disease. A review of the published literature was therefore performed with the goal of comparing the accuracy of clinical diagnostic measures with that of surgical diagnosis. The current body of evidence suggests that clinical diagnosis of symptomatic endometriosis is more reliable than previously recognized and that surgical diagnosis has limitations that could be underappreciated. Regardless of the methodology used, women with suspected symptomatic endometriosis would be well served by a diagnostic paradigm that is reliable, conveys minimal risk of under‐ or over‐diagnosis, lessens the time from symptom development to diagnosis, and guides the appropriate use of medical and surgical management strategies.
Analysis of the far‐medial transoral endoscopic approach to the infratemporal fossa
Authors: Patwa Hafiz S. , Yanez‐Siller Juan C. , Gomez Galarce Matias , Otto Bradley A. , Prevedello Daniel M. , Carrau Ricardo L.
Published: May 2018

Objectives/Hypothesis

To demonstrate anatomic relationships of the far‐medial transoral endoscopic assisted approach (FMT‐EAA) to the infratemporal fossa (ITF) and define the corridor dimensions, surgical freedom, and limitations associated with this approach.

Study Design

Cadaveric study.

Methods

Twenty ITFs (10 specimens) were dissected with the assistance of 0 °, 30 °, and 45 ° rod‐lens endoscopes. Image guidance was used to confirm and measure the corridors' structural boundaries and document the anatomical relationships encountered in this approach.

Results

Access to the ITF via the FMT‐EAA can be divided into two secondary surgical corridors: the superomedial and inferolateral triangles, each of which provides access to different areas. The superomedial triangle is bounded medially by the lateral pterygoid plate and posterolateral maxillary sinus wall, superiorly by the greater sphenoid wing, and inferolaterally by the lateral pterygoid muscle. The inferolateral triangle is bounded superiorly by the lower head of the lateral pterygoid muscle, inferiorly by the medial pterygoid muscle, and laterally by the mandible. Using a standard 19‐mm endoscope, the FMT‐EAA achieves a mean surgical freedom of 231 mm and 161 mm in the vertical and horizontal planes, respectively.

Conclusions

FMT‐EAA adequately exposes critical structures of the ITF. This technique is a viable option for the management of selected ITF lesions, either alone or in combination with alternative minimally invasive approaches to the region.

Level of Evidence

NA Laryngoscope, 128:2273–2281, 2018
Laryngeal precursor lesions: Interrater and intrarater reliability of histopathological assessment
Authors: Mehlum Camilla Slot , Larsen Stine Rosenkilde , Kiss Katalin , Groentved Aagot Moeller , Kjaergaard Thomas , Möller Sören , Godballe Christian
Published: May 2018

Objective

The World Health Organization classification (WHOC) 2017 of low‐grade versus high‐grade laryngeal dysplasia recently replaced the previous WHOC 2005 of mild, moderate, and severe dysplasia and carcinoma in situ. Our objectives were to compare the interrater agreement of the WHOC 2017 with that of the WHOC 2005 and to test the intra‐rater agreement of the WHOC 2005.

Methods

Two expert head and neck pathologists rated 211 tissue samples that were initially diagnosed with laryngeal precursor lesions. The samples were rated twice according to the WHOC 2005 and once according to the WHOC 2017; estimates of interrater and intrarater agreements were calculated with kappa statistics.

Results

The crude intrarater agreements using the WHOC 2005 were 0.93 for rater 1 and 0.62 for rater 2. The corresponding unweighted kappa values were 0.90 (95% confidence interval [CI], 0.86–0.95) for rater 1 and 0.43 (95% CI, 0.35–0.54) for rater 2, whereas the standard linear weighted kappa values were 0.93 (95% CI, 0.90–0.97) for rater 1 and 0.60 (95% CI, 0.53–0.69) for rater 2. The crude interrater agreement for the WHOC 2005 was 0.57, with a corresponding unweighted kappa value 0.38 (95% CI, 0.31–0.48) and a standard linear weighted kappa value 0.52 (95% CI, 0.42–0.60). The crude interrater agreement for the WHOC 2017 was 0.83, with a corresponding unweighted kappa value 0.45 (95% CI, 0.31–0.59) and a standard linear weighted kappa value 0.46 (95% CI, 0.30–0.60).

Conclusion

Our results indicate difficulties in providing reliable diagnosis of laryngeal precursor lesions, even with experienced head and neck pathologists and the application of a newly revised classification system.

Level of Evidence

4. Laryngoscope, 128:2375–2379, 2018
Treating pediatric post‐tonsillectomy pain and nausea with complementary and alternative medicine
Authors: Keefe Katherine R. , Byrne Kevin J. , Levi Jessica R.
Published: May 2018

Objectives

Although tonsillectomy is a common and largely safe procedure, pain management in children remains a controversial topic. In addition to the challenge of choosing appropriate analgesia, there is often low parent and child adherence. This article presents a review, and evaluates the potential role, of a range of complementary and alternative therapies that may be sought out by parents.

Methods

A literature review of complementary and alternative interventions performed using PubMed, Cochrane Library, and EMBASE, supplemented by searches from Google and hand searches of cross‐references of selected articles, yielded 32 studies for qualitative analysis.

Results

The studies included for analysis investigated a wide variety of alternative treatment modalities: acupuncture and related therapies, aromatherapy, homeopathy, honey, intravenous fluid, speech therapy, hyaluronic acid, behavioral therapies, ice/cold, hydrogen peroxide rinse, and chewing gum.

Conclusion

At this time, stronger conclusions cannot be made about the therapies investigated because there are many methodology limitations of the studies analyzed. However, our results suggest merit for these treatments as adjuvant therapies that can enhance analgesia and decrease requirements of controversial medications. Honey and acupuncture have the greatest amount of evidence for postoperative pain and nausea; however, all interventions examined were cost‐effective and safe. We recommend against hydrogen peroxide rinses and chewing gum. Laryngoscope, 2625–2634, 2018
The impact of diet‐induced hepatic steatosis in a murine model of hepatic ischemia/reperfusion injury
Authors: Liss Kim H. H. , McCommis Kyle S. , Chambers Kari T. , Pietka Terri A. , Schweitzer George G. , Park Sara L. , Nalbantoglu Ilke , Weinheimer Carla J. , Hall Angela M. , Finck Brian N.
Published: May 2018

The prevalence of obesity‐associated nonalcoholic fatty liver disease has significantly increased over the past decade, and end‐stage liver disease secondary to nonalcoholic steatohepatitis has become 1 of the most common indications for liver transplantation. This both increases the demand for organs and decreases the availability of donor livers deemed suitable for transplantation. Although in the past many steatotic livers were discarded due to concerns over enhanced susceptibility to ischemia/reperfusion injury (IRI) and organ failure, the discrepancy between supply and demand has resulted in increasing use of expanded criteria donor organs including steatotic livers. However, it remains controversial whether steatotic livers can be safely used for transplantation and how best to improve the performance of steatotic grafts. We aimed to evaluate the impact of diet‐induced hepatic steatosis in a murine model of IRI. Using a diet of high trans‐fat, fructose, and cholesterol (HTF‐C) and a diet high in saturated fats, sucrose, and cholesterol (Western diet), we were able to establish models of mixed macrovesicular and microvesicular steatosis (HTF‐C) and microvesicular steatosis (Western). We found that the presence of hepatic steatosis, whether it is predominantly macrovesicular or microvesicular, significantly worsens IRI as measured by plasma alanine aminotransferase levels and inflammatory cytokine concentration, and histological evaluation for necrosis. Additionally, we report on a novel finding in which hepatic IRI in the setting of steatosis results in the induction of the necroptosis factors, receptor interacting protein kinase (RIPK) 3, RIPK1, and mixed‐lineage kinase domain‐like. These data lay the groundwork for additional experimentation to test potential therapeutic approaches to limit IRI in steatotic livers by using a genetically tractable system. Liver Transplantation 24 908–921 2018 AASLD.
Palliative care in end‐stage liver disease: Time to do better?
Authors: Mazzarelli Chiara , Prentice Wendy M. , Heneghan Michael A. , Belli Luca S. , Agarwal Kosh , Cannon Mary D.
Published: May 2018

Optimal involvement of palliative care (PC) services in the management of patients with decompensated cirrhosis and end‐stage liver disease (ESLD) is limited. This may result from both ignorance and the failure to recognize the spectrum and unpredictability of the underlying liver condition. Palliative care is a branch of medicine that focuses on quality of life (QoL) by optimizing symptom management and providing psychosocial, spiritual, and practical support for both patients and their caregivers. Historically, palliative care has been underutilized for patients with decompensated liver disease. This review provides an evidence‐based analysis of the benefits of the integration of palliative care into the management of patients with ESLD. Liver Transplantation 24 961–968 2018 AASLD.
Multicenter Study of Staging and Therapeutic Predictors of Hepatocellular Carcinoma Recurrence Following Transplantation
Authors: Welling Theodore H. , Eddinger Kevin , Carrier Kristen , Zhu Danting , Kleaveland Tyler , Moore Derek E. , Schaubel Douglas E. , Abt Peter L.
Published: May 2018

Orthotopic liver transplantation (OLT) and resection are effective treatments for hepatocellular carcinoma (HCC). However, optimizing OLT and limiting HCC recurrence remains a vexing problem. New HCC Model for End‐Stage Liver Disease and allocation algorithms provide greater observation of HCC patients, many while receiving local‐regional treatments. Potential benefits of local‐regional treatment for limiting HCC recurrence after OLT remain incompletely understood. Therefore, we aimed to define HCC‐specific prognostic factors affecting recurrence in a contemporary, multicenter cohort of HCC patients undergoing OLT and specifically whether local‐regional therapies limited recurrence. We identified 441 patients undergoing OLT for HCC at 3 major transplant centers from 2008 to 2013. Cox regression was used to analyze covariate‐adjusted recurrence and mortality rates after OLT. “Bridging” or “downstaging” therapy was used in 238 (54%) patients with transarterial chemoembolization (TACE) being used in 170 (71%) of treated patients. The survival rate after OLT was 88% and 78% at 1 and 3 years, respectively, with HCC recurrence (28% of deaths) significantly increasing the mortality rate (hazard ratio [HR], 19.87; P < 0.001). Tumor size, not tumor number, either at presentation or on explant independently predicted HCC recurrence (HR, 1.36 and 1.73, respectively; P < 0.05) with a threshold effect noted at 4.0‐cm size. Local‐regional therapy (TACE) reduced HCC recurrence by 64% when adjusting for presenting tumor size (HR, 0.36; P < 0.05). Explant tumor size and microvascular invasion predicted mortality (HR, 1.19 and 1.51, respectively; P < 0.05) and pathologic response to therapy (TACE or radiofrequency ablation) significantly decreased explant tumor size (0.56‐1.62 cm diameter reduction; P < 0.05). In conclusion, HCC tumor size at presentation or explant is the most important predictor for HCC recurrence after OLT. Local‐regional therapy to achieve a pathologic response (decreasing tumor size) can limit HCC recurrences after OLT. Liver Transplantation 00 000–000 2018 AASLD.
Improving resolution of MR images with an adversarial network incorporating images with different contrast
Authors: Kim Ki Hwan , Do Won‐Joon , Park Sung‐Hong
Published: May 2018

Purpose

The routine MRI scan protocol consists of multiple pulse sequences that acquire images of varying contrast. Since high frequency contents such as edges are not significantly affected by image contrast, down‐sampled images in one contrast may be improved by high resolution (HR) images acquired in another contrast, reducing the total scan time. In this study, we propose a new deep learning framework that uses HR MR images in one contrast to generate HR MR images from highly down‐sampled MR images in another contrast.

Materials and Methods

The proposed convolutional neural network (CNN) framework consists of two CNNs: (a) a reconstruction CNN for generating HR images from the down‐sampled images using HR images acquired with a different MRI sequence and (b) a discriminator CNN for improving the perceptual quality of the generated HR images. The proposed method was evaluated using a public brain tumor database and in vivo datasets. The performance of the proposed method was assessed in tumor and no‐tumor cases separately, with perceptual image quality being judged by a radiologist. To overcome the challenge of training the network with a small number of available in vivo datasets, the network was pretrained using the public database and then fine‐tuned using the small number of in vivo datasets. The performance of the proposed method was also compared to that of several compressed sensing (CS) algorithms.

Results

Incorporating HR images of another contrast improved the quantitative assessments of the generated HR image in reference to ground truth. Also, incorporating a discriminator CNN yielded perceptually higher image quality. These results were verified in regions of normal tissue as well as tumors for various MRI sequences from pseudo k‐space data generated from the public database. The combination of pretraining with the public database and fine‐tuning with the small number of real k‐space datasets enhanced the performance of CNNs in in vivo application compared to training CNNs from scratch. The proposed method outperformed the compressed sensing methods.

Conclusions

The proposed method can be a good strategy for accelerating routine MRI scanning.
Advanced Collapsed cone Engine dose calculations in tissue media for COMS eye plaques loaded with I‐125 seeds
Authors: Morrison Hali , Menon Geetha , Larocque Matthew P. , van Veelen Bob , Niatsetski Yury , Weis Ezekiel , Sloboda Ron S.
Published: May 2018

Purpose

To investigate the dose calculation accuracy of the Advanced Collapsed cone Engine (ACE) algorithm for ocular brachytherapy using a COMS plaque loaded with I‐125 seeds for two heterogeneous patient tissue scenarios.

Methods

The Oncura model 6711 I‐125 seed and 16 mm COMS plaque were added to a research version (v4.6) of the Oncentra® Brachy (OcB) treatment planning system (TPS) for dose calculations using ACE. Treatment plans were created for two heterogeneous cases: (a) a voxelized eye phantom comprising realistic eye materials and densities and (b) a patient CT dataset with variable densities throughout the dataset. ACE dose calculations were performed using a high accuracy mode, high‐resolution calculation grid matching the imported CT datasets (0.5 × 0.5 × 0.5 mm3), and a user‐defined CT calibration curve. The accuracy of ACE was evaluated by replicating the plan geometries and comparing to Monte Carlo (MC) calculated doses obtained using MCNP6. The effects of the heterogeneous patient tissues on the dose distributions were also evaluated by performing the ACE and MCNP6 calculations for the same scenarios but setting all tissues and air to water.

Results

Average local percent dose differences between ACE and MC within contoured structures and at points of interest for both scenarios ranged from 1.2% to 20.9%, and along the plaque central axis (CAX) from 0.7% to 7.8%. The largest differences occurred in the plaque penumbra (up to 17%), and at contoured structure interfaces (up to 20%). Other regions in the eye agreed more closely, within the uncertainties of ACE dose calculations (~5%). Compared to that, dose differences between water‐based and fully heterogeneous tissue simulations were up to 27%.

Conclusions

Overall, ACE dosimetry agreed well with MC in the tumor volume and along the plaque CAX for the two heterogeneous tissue scenarios, indicating that ACE could potentially be used for clinical ocular brachytherapy dosimetry. In general, ACE data matched the fully heterogeneous MC data more closely than water‐based data, even in regions where the ACE accuracy was relatively low. However, depending on the plaque position, doses to critical structures near the plaque penumbra or at tissue interfaces were less accurate, indicating that improvements may be necessary. More extensive knowledge of eye tissue compositions is still required.
Determination of tebuconazole and penconazole fungicides in rat and human hair by liquid chromatography/tandem mass spectrometry
Authors: Polledri Elisa , Mercadante Rosa , Fustinoni Silvia
Published: May 2018

Rationale

Tebuconazole (TEB) and penconazole (PEN) are widely applied fungicides and environmental contaminants; their toxicological properties include possible effects to the unborn child, therefore, the evaluation of human exposure is relevant to risk assessment. Hair is a non‐invasive specimen that incorporates pollutants allowing an extended exposure window to be surveyed. The aim of this work was to develop and validate an assay for the determination of TEB and PEN in human hair.

Methods

Under optimised conditions, analytes were extracted by soaking hair in acetonitrile, in the presence of deuterated analogues, under heating and agitation. Chemical separation was achieved using a C18 reversed‐phase chromatographic column and detection and quantification were performed, after positive electrospray ionization, by triple quadrupole mass spectrometry operating in selected reaction monitoring mode.

Results

The assay validation showed a linear dynamic range up to 5 μg/L or 200 pg/mg hair, inter‐ and intra‐run precisions <6%, and accuracies within 5% of spiked concentrations. Limits of quantification were 0.001 μg/L or 1 pg/mg hair for both TEB and PEN. Matrix effect experiments showed that the isotope dilution approach allowed for the control of bias sources. TEB and PEN were determined in hair of rats exposed to a low dose of TEB and in hair of agricultural workers exposed to TEB and/or PEN during the application season, indicating that both chemicals are incorporated into the hair upon exposure.

Conclusions

The results of this study indicate that the developed assay is useful to evaluate the exposure to TEB and PEN in humans.
Effects of solvent parameters on the electrospray ionization tandem mass spectrometry response of glucose
Authors: Thacker Jonathan B. , Schug Kevin A.
Published: May 2018

Rationale

The importance of saccharides, the most abundant biomolecules on Earth, extends beyond their biological roles and to consumer products and industrial processes. Electrospray ionization tandem mass spectrometry (ESI‐MS/MS) is an attractive tool for the analysis of underivatized saccharides (US), but they tend to have relatively low sensitivities due to their low surface activities and lack of easily protonable or deprotonable chemical groups. An understanding of the influences that solvent parameters have on their signal intensities would enhance the usefulness of ESI‐MS/MS for their analysis.

Methods

Solutions of glucose, a model analyte for US, in various combinations of solvent, additive, additive concentration, and pH were analyzed by flow injection analysis ESI‐MS/MS in both the positive and negative ionization mode. The blank‐corrected signal intensities of the solvent parameter combinations were then compared.

Results

The addition of acetonitrile led to severe ionization suppression in the positive ionization mode through its competition with glucose for cation adduction. High signal intensity was achieved under wide pH and concentration ranges for methanol: water solutions containing ammonium trifluoroacetate in the positive ionization mode. The highest signal intensities for acetonitrile: water solutions were those containing ammonium formate or lithium fluoride in the negative ionization mode.

Conclusions

An understanding of the influence of solvent parameters on the signal intensity of a given analyte is useful for guiding the selection process of mobile phases/flow solvents that lead to low limits of detection or the minimization of matrix effects by allowing its detection at high dilution factors.
Rapid analysis of carboxylic acids and esters with a direct analysis in real time ion source
Authors: Wang Sheng‐Kang , Wei Xian‐Yong , Li Sheng , Liu Fang‐Jing , Wang Yu‐Gao , Li Zhan‐Ku , Shi Chong , Yang Zheng , Zong Zhi‐Min
Published: May 2018

Rationale

Coal oxidation produces carboxylic acids (CAs), including aliphatic acids, benzoic acids, and benzenepolycarboxylic acids, which are important fine chemicals which could be used to understand the structural features of coals. However, detecting CAs usually presents great challenges due to extremely troublesome pretreatments. Therefore, it is essential to develop an analytical method for the rapid detection of CAs from coal oxidation.

Methods

A series of model compounds (MCs) of oxidation products and two practical samples were investigated by direct analysis in real time time‐of‐flight mass spectrometry (DART‐TOFMS) under three different analytical conditions (ionizing gas temperature, organic solvent, and MC concentration).

Results

Ionizing methyl benzoate, dimethyl phthalate, and dimethyl adipate produces typical ions of methyl esters, including [M − OCH3]+, [M + H]+, and [M + NH4]+. In contrast, the characteristic ions generated from CAs are polymer ions, such as [2 M + NH4]+, [3 M + NH4]+, [4 M + NH4]+, and [5 M + NH4]+, indicating the strong intermolecular hydrogen‐bond interaction among CAs.

Conclusions

Results suggest that DART‐TOFMS could rapidly analyze CAs or esters in coal oxidation products according to their typical ions to further gain deep insights into the coal structure.
Preparation and Physical Properties of Porous Starch/Natural Rubber Composites
Authors: Wu Jie , Li Kuncai , Pan Xuemei , Liao Shuangquan , You Jianhua , Zhu Kaizheng , Wang Zhifen
Published: May 2018

Porous starch is modified by the addition of dodecenyl succinate anhydride (DDSA), to decrease the self‐aggregation, and then blended with natural rubber (NR) latex to obtain the modified starch/NR composites. The composites are found to have improved properties compared with the corresponding pure NR. Results of a thermal analysis show that the thermal degradation reaction of modified starch/NR composites is a two‐step reaction, with the initial (T0) and the final (Tf) temperatures of main reaction being increased, and glass transition temperature (Tg) slightly reduced compared with the corresponding pure NR. The curves of elastic modulus (G′) and loss factor (tanδ) versus the strain of unvulcanized rubber compounds are obtained using a rubber process analyzer. Dynamic mechanical thermal analysis shows that the rolling resistance of the composites is improved by the addition of modified starch.
Synthesis, Characterization, and Antifungal Activity of N‐Quaternized and N‐Diquaternized Chitin Derivatives
Authors: Luan Fang , Wei Lijie , Zhang Jingjing , Tan Wenqiang , Chen Yuan , Wang Ping , Dong Fang , Li Qing , Guo Zhanyong
Published: May 2018

To improve the bioactivity of chitin (CT), novel N‐quaternized (QCT), and N‐diquaternized (DQCT) CT derivatives are synthesized through a series of reactions from CT. The derivatives are characterized using elemental analysis, FTIR, and 13C NMR. In addition, the inhibitory effects of the compounds against three fungi (B. cinerea, F. oxysporum, and P. asparagi) are tested. The inhibitory indices of CT, QCT, and DQCT are 12–15%, 63–73%, and 74–89%, respectively, at 1.0 mg mL−1. The antifungal activities are in the order of DQCT > QCT > CT, which correlated with the number of quaternized groups. Based on these results, it is concluded that the antifungal activity of CT is improved by the introduction of quaternized groups on CT backbone.
In Vitro Starch Digestion and Colonic Fermentation of Thai Jasmine Rice
Authors: Ayimbila Francis , Keawsompong Suttipun
Published: May 2018

Resistant starch (RS) enhances gastrointestinal (GI) health but RS content in rice varies depending on cooking and storage conditions. Hydrolysis rates of in vitro starch fractions in simulated GI, colonic fermentation of freshly cooked Thai jasmine rice (control) by rice cooker method (RCM) and boiling method (BM), and reheated jasmine rice stored for 3 days at 4 and −20 °C are evaluated. Storage increased RS, slowly digestible starch (SDS) content of jasmine rice cooked by RCM, and SDS content of jasmine rice cooked by BM due to the decrease in rapidly digestible starch (RDS). The effect of storage on starch fractions in jasmine rice differed with temperature. For simulated GI conditions, 50.07% of jasmine rice hydrolysate escaped hydrolysis similarly among treatments. Jasmine rice hydrolysates selectively enhanced growth of probiotic strains but not pathogenic growth with time. Maximum specific growth rates (μmax, h−1) of strains were measured as Bifidobacterium animalis 2194 > Bifidobacterium bifidum TISTR 2129 > Lactobacillus reuteri AC‐5 > Escherichia coli E010 ≥ Salmonella serovar Enteritidis S003. With regard to quantity and quality, jasmine rice hydrolysate was not affected by cooking and storage conditions but influenced by colonic fermentation.
Are the effects of methylphenidate uncertain?
Authors: Cortese S.
Published: May 2018

Objectives

A recent systematic review and meta-analysis of randomised controlled trials of methylphenidate (MPH) in children and adolescents by a Cochrane group, led by Storebø, raised concern around the level of evidence supporting the use of this medication for attention-deficit/hyperactivity disorder (ADHD) in children and adolescents. This led to several critical responses from a number of ADHD experts.

Methods

This paper reviews the conclusions reached from the Storebø meta-analysis by a critical analysis of methodologies used along with drawing on extant literature.

Results

The controversy raised by the Cochrane meta-analysis should lead to a balanced reflection on the research priorities and needs for the field.

Conclusions

It is hoped the controversy will ultimately lead to improve the quality of the research on the efficacy, effectiveness and tolerability of MPH for ADHD.
A survey on stereo vision-based autonomous navigation for multi-rotor MUAVs
Authors: Sanchez-Rodriguez Jose-Pablo , Aceves-Lopez Alejandro
Published: May 2018

This paper presents an overview of the most recent vision-based multi-rotor micro unmanned aerial vehicles (MUAVs) intended for autonomous navigation using a stereoscopic camera. Drone operation is difficult because pilots need the expertise to fly the drones. Pilots have a limited field of view, and unfortunate situations, such as loss of line of sight or collision with objects such as wires and branches, can happen. Autonomous navigation is an even more difficult challenge than remote control navigation because the drones must make decisions on their own in real time and simultaneously build maps of their surroundings if none is available. Moreover, MUAVs are limited in terms of useful payload capability and energy consumption. Therefore, a drone must be equipped with small sensors, and it must carry low weight. In addition, a drone requires a sufficiently powerful onboard computer so that it can understand its surroundings and navigate accordingly to achieve its goal safely. A stereoscopic camera is considered a suitable sensor because of its three-dimensional (3D) capabilities. Hence, a drone can perform vision-based navigation through object recognition and self-localise inside a map if one is available; otherwise, its autonomous navigation creates a simultaneous localisation and mapping problem.
Probable transmission routes of the influenza virus in a nosocomial outbreak
Authors: Xiao S. , Tang J. W. , Hui D. S. , Lei H. , Yu H. , Li Y.
Published: May 2018

Influenza is a long-standing public health concern, but its transmission remains poorly understood. To have a better knowledge of influenza transmission, we carried out a detailed modelling investigation in a nosocomial influenza outbreak in Hong Kong. We identified three hypothesised transmission modes between index patient and other inpatients based on the long-range airborne and fomite routes. We considered three kinds of healthcare workers’ routine round pathways in 1140 scenarios with various values of important parameters. In each scenario, we used a multi-agent modelling framework to estimate the infection risk for each hypothesis and conducted least-squares fitting to evaluate the hypotheses by comparing the distribution of the infection risk with that of the attack rates. Amongst the hypotheses tested in the 1140 scenarios, the prediction of modes involving the long-range airborne route fit better with the attack rates, and that of the two-route transmission mode had the best fit, with the long-range airborne route contributing about 94% and the fomite route contributing 6% to the infections. Under the assumed conditions, the influenza virus was likely to have spread via a combined long-range airborne and fomite routes, with the former predominant and the latter negligible.
From Microscale (400 μl) to Macroscale (425 L): Experimental Investigations of the CO2/N2‐CH4 Exchange in Gas Hydrates Simulating the Iġnik Sikumi Field Trial
Authors: Schicks J. M. , Strauch B. , Heeschen K. U. , Spangenberg E. , Luzi‐Helbing M.
Published: May 2018

In 2012 the production of CH4 from hydrate‐bearing sediments via CO2 injection was conducted in the framework of the Iġnik Sikumi Field Trial in Alaska, USA. In order to preserve the injectivity by avoiding a formation of CO2 hydrate in the near‐well region, a mixture containing 77 mol% N2 and 23 mol% CO2 was chosen. The interpretation of the complex test results was difficult, and the nature of the interaction between the N2‐CO2 mixture and the initial CH4 hydrate could not be clarified. In this study we present the results of our experimental investigations simulating the Iġnik Sikumi Field Trial at different scales. We conducted (1) in situ Raman spectroscopic investigations to study the exchange process of the guest molecules in the hydrate phase on a molecular level in a flow‐through pressure cell with a volume of 0.393 ml, (2) batch experiments with pure hydrates and hydrate‐bearing sediments in pressure cells with volumes of 420 ml, and (3) the injection of a CO2‐N2 mixture into a hydrate‐bearing sediment in a large‐scale reservoir simulator with a total volume of 425 L. The results indicate a dissociation of the initial CH4 hydrate rather than an exchange reaction. The formation of a secondary mixed hydrate phase may occur, but this process strongly depends on the local composition of the gas phase and the pressure at given temperature.
Mineralogical Controls on Frictional Strength, Stability, and Shear Permeability Evolution of Fractures
Authors: Fang Yi , Elsworth Derek , Wang Chaoyi , Jia Yunzhong
Published: May 2018

Massive fluid injection into the subsurface can induce microearthquakes by reactivating preexisting faults or fractures as seismic or aseismic slip. Such seismic or aseismic shear deformations may result in different modes of permeability evolution. Previous experimental studies have explored frictional stability‐permeability relationships of carbonate‐rich and phyllosilicate‐rich samples under shear, suggesting that friction‐permeability relationship may be primarily controlled by fracture minerals. We examine this relationship and identify the role of mineralogy (i.e., tectosilicate, carbonate, and phyllosilicate content) using direct‐shear experiments on smooth saw‐cut fractures of natural rocks and sintered fractures with distinct mineralogical compositions. These results indicate that the friction‐permeability relationship is controlled by mineralogy. Frictional strength and permeability change upon reactivation decrease with phyllosilicate content but increase with tectosilicate content. In contrast, the reverse trend is observed for frictional stability (a‐b). However, the permeability change decreases with carbonate content while both frictional strength and stability increase. The permeability change always decreases with an increase in frictional stability. This relationship implies a new mechanical‐hydro‐chemical coupling loop via a linkage of frictional properties, mineralogy, and permeability.
Stress Influence on Fracture Aperture and Permeability of Fragmented Rocks
Authors: Agheshlui Hossein , Sedaghat Mohammad H. , Matthai Stephan
Published: May 2018

The influence of far‐field stresses on fracture apertures in a fragmented rock layer is investigated using finite element analysis of a three‐dimensional mechanical model. The model implements realistic boundary conditions, interactions between the fragmented layer and neighboring plastic rock layers, and frictional interfaces between the rock blocks. Stress‐strain analysis is conducted to obtain stress variations within the fragmented rock layer and the block displacements and rotations. The fracture apertures are calculated using the local stress states instead of the far‐field stresses simply being projected on the fractures. It is observed that fracture apertures can vary for the fracture segments over the individual blocks. Ensemble permeability is calculated by running a single‐phase flow analysis considering the obtained fracture apertures for fracture segments. The influence of the rock block displacements, rotations and deformations, difference between the mechanical properties of the rock layers, and the orientation of the horizontal stresses is investigated on the ensemble permeability. It is demonstrated that the compressibility of the neighboring layers and block rotations and deformations have significant influence on the permeability of the fragmented rock layer. These effects, which may be ignored in simpler aperture calculation models, can result in considerable inaccuracies in the estimation of fracture apertures and ensemble permeability. Hence, such methods may only be used as indicative tools.
What Drives the Lateral Versus Vertical Propagation of Dikes? Insights From Analogue Models
Authors: Urbani S. , Acocella V. , Rivalta E.
Published: May 2018

Volcanic eruptions are usually fed by dikes. Understanding how crustal inhomogeneities and topographic loads control the direction (lateral/vertical) and extent (propagation/arrest) of dikes is crucial to forecast the opening of a vent. Many factors, including buoyancy, crustal layering, and topography, may control the vertical or lateral propagation of a dike. To define a hierarchy between these factors, we have conducted analogue models, injecting water (magma analogue) within gelatin (crust analogue). We investigate the effect of crustal layering (both rigidity and density layering), topography, magma inflow rate, and the density ratio between host rock and magma. Based on the experimental observations and scaling considerations, we suggest that rigidity layering (a stiffer layer overlying a weaker one) and topographic gradient favor predominantly lateral dike propagation; inflow rate, density layering, and density ratio play a subordinate role. Conversely, a softer layer overlying a stiffer one favors vertical propagation. Our results highlight the higher efficiency of a stiff layer in driving lateral dike propagation and/or inhibiting vertical propagation with respect to the Level of Neutral Buoyancy proposed by previous studies.
A Terrestrial Gamma‐Ray Flash inside the Eyewall of Hurricane Patricia
Authors: Bowers G. S. , Smith D. M. , Kelley N. A. , Martinez‐McKinney G. F. , Cummer S. A. , Dwyer J. R. , Heckman S. , Holzworth R. H. , Marks F. , Reasor P. , Gamache J. , Dunion J. , Richards T. , Rassoul H. K.
Published: May 2018

On 23 October 2015 at ~1732 UTC, the Airborne Detector for Energetic Lightning Emissions (ADELE) flew through the eyewall of Hurricane Patricia aboard National Oceanic and Atmospheric Administration's Hurricane Hunter WP‐3D Orion, observing the first terrestrial gamma‐ray flash (TGF) ever seen in that context, and the first ever viewed from behind the forward direction of the main TGF gamma‐ray burst. ADELE measured 184 counts of ionizing radiation within 150 μs, coincident with the detection of a nearby lightning flash. Lightning characteristics inferred from the associated radio signal and comparison of the gamma‐ray energy spectrum to simulations suggests that this is the first observation of a reverse beam of positrons predicted by the leading TGF production model, relativistic runaway electron avalanches. This paper presents the first experimental evidence of a previously predicted second component of gamma‐ray emission from TGFs. The brightest emission, commonly observed from orbit, is from the relativistic runaway electron avalanche bremsstrahlung; the second, fainter component reported here is from the bremsstrahlung of positrons propagating in the reverse direction. This reverse gamma‐ray beam penetrates to low enough altitudes to allow ground‐based detection of typical upward TGFs from mountain observatories.
Retrieval of Aerosol Optical Depth From INSAT‐3D Imager Over Asian Landmass and Adjoining Ocean: Retrieval Uncertainty and Validation
Authors: Mishra Manoj K.
Published: May 2018

An algorithm for aerosol optical depth (τ) retrieval from imager data onboard geostationary Indian National Satellite (INSAT‐3D) is described. The basic principles of the algorithm are adopted from Geostationary Observational Environmental Satellite Aerosol and Smoke Algorithm, where darkest observations over a time period and constant background aerosol optical depth (τb) value are used to derive surface reflectance. However, in INSAT‐3D algorithm spatially and temporally dynamic τb derived from Moderate Resolution Imaging Spectroradiometer (MODIS)‐aqua is used. The theoretical simulations suggest retrieval uncertainty of around ±30–45% depending on the certainty of aerosol optical properties and other parameters used in radiative transfer calculations. Retrieval uncertainty is less over dark regions and lower scattering angles. INSAT‐3D τ at 0.55 μm is derived operationally for the first time over Asia and adjoining ocean at 30‐min temporal resolution. The retrieval algorithm is validated against in situ Sun‐sky radiometer measurements at 26 Aerosol Robotic Network sites and Sun‐photometer measurements during Sagar‐Sampada cruise in the northern Arabian Sea. The validation study encompassing 3,803 and 844 data points over land and ocean stations show correlations ranging from 0.70 to 0.91 and 0.79 to 0.91, respectively. The uncertainty of retrievals is within 45% over land and within 30% over ocean. The diurnal variability of INSAT‐3D and Aerosol Robotic Network τ in India and southeast Asia is also presented. The comparison of INSAT‐3D and MODIS‐aqua monthly average τ shows correlation ranging from 0.74 to 0.89 and 0.65 to 0.97 over Indian landmass and adjoining ocean, respectively. The validation suggests that INSAT‐3D can be used for aerosol monitoring and can be merged with MODIS‐aqua/terra aerosol product to generate combined aerosol product at high temporal resolution.
Local and Remote Planetary Wave Effects on Polar Mesospheric Clouds in the Northern Hemisphere in 2014
Authors: France J. A. , Randall C. E. , Lieberman R. S. , Harvey V. L. , Eckermann S. D. , Siskind D. E. , Lumpe J. D. , Bailey S. M. , Carstens J. N. , Russell J. M.
Published: May 2018

Observations by the Cloud Imaging and Particle Size (CIPS) instrument on the Aeronomy of Ice in the Mesosphere (AIM) satellite show an anomalous decline in Northern Hemisphere polar mesospheric clouds (PMCs) from 26 July to 6 August 2014. The decline is attributed to local warming associated with the quasi‐two‐day wave and interhemispheric coupling (IHC) triggered by planetary wave breaking in the Antarctic (winter) stratosphere. The results indicate that the IHC in 2014 occurred via a pathway that previous studies have not emphasized. Based on observations from the Aura Microwave Limb Sounder (MLS) and reanalyses from both the Modern‐Era Retrospective analysis for Research and Applications, Version 2 (MERRA‐2) and the Navy Global Environmental Model (NAVGEM), we argue that a strengthening of the summer easterly jet gave rise to enhanced meridional and vertical shear along its equatorward flank, which supported growth of the two‐day wave. The two‐day wave led to enhanced meridional mixing in northern midlatitudes and a weakening of the northern branch of the mesospheric residual circulation, reducing ascent and warming the polar summer mesopause. In 2014, the five‐day planetary wave modulated the response to IHC such that PMCs persisted in its cold phases even though zonal mean temperatures were too high to support PMCs, and were absent in the warm phases when zonal mean temperatures were low enough to support PMCs.