bluuebunny/crossref_metadata_2025 huggingface dataset:
Cuprizone‐induced demyelination triggers a CD8‐pronounced T cell recruitment
Authors: Kaddatz Hannes , Joost Sarah , Nedelcu Julia , Chrzanowski Uta , Schmitz Christoph , Gingele Stefan , Gudi Viktoria , Stangel Martin , Zhan Jiangshan , Santrau Emily , Greiner Theresa , Frenz Julia , Müller‐Hilke Brigitte , Müller Michael , Amor Sandra , van der Valk Paul , Kipp Markus
Published: November 2020

The loss of myelinating oligodendrocytes is a key characteristic of many neurological diseases, including Multiple Sclerosis (MS). In progressive MS, where effective treatment options are limited, peripheral immune cells can be found at the site of demyelination and are suggested to play a functional role during disease progression. In this study, we hypothesize that metabolic oligodendrocyte injury, caused by feeding the copper chelator cuprizone, is a potent trigger for peripheral immune cell recruitment into the central nervous system (CNS). We used immunohistochemistry and flow cytometry to evaluate the composition, density, and activation status of infiltrating T lymphocytes in cuprizone‐intoxicated mice and post‐mortem progressive MS tissues. Our results demonstrate a predominance of CD8+ T cells along with high proliferation rates and cytotoxic granule expression, indicating an antigenic and pro‐inflammatory milieu in the CNS of cuprizone‐intoxicated mice. Numbers of recruited T cells and the composition of lymphocytic infiltrates in cuprizone‐intoxicated mice were found to be comparable to those found in progressive MS lesions. Finally, amelioration of the cuprizone‐induced pathology by treating mice with laquinimod significantly reduces the number of recruited T cells. Overall, this study provides strong evidence that toxic demyelination is a sufficient trigger for T cells to infiltrate the demyelinated CNS. Further investigation of the mode of action and functional consequence of T cell recruitment might offer promising new therapeutic approaches for progressive MS.
Instability of PVDF Binder in the LiFePO4versus Li4Ti5O12 Li‐Ion Battery Cell
Authors: Leanza Daniela , Vaz C. A. F. , Novák Petr , El Kazzi Mario
Published: November 2020

The conventional formulation of electrodes used in Li‐ion batteries consists of a mixture of three components: an active material, a conductive additive (carbon), and an organic binder. While the first encompasses a broad spectrum of chemistries, the carbon and the binder are often standard elements of the composite, with the latter being, in most of the cathode cases, the polyvinylidene fluoride (PVDF). The high (electro‐)chemical inertia spanning over a broad range of oxidative and reductive potentials gives grounds for this choice. Herein, we demonstrate, contrary to electrochemical expectations, that the PVDF is electrochemically unstable at relatively low potentials. We consider in this study the LiFePO4 (LFP) cathode cycled versus Li4Ti5O12 (LTO) anode as a representative low‐voltage battery cell system. The binder degradation process starts upon charge on the LFP electrode at 3.45 V vs. Li+/Li when the PVDF binder reacts with lithium and forms LiF. The latter does not precipitate on the LFP but migrates/diffuses towards the LTO counter‐electrode, following the Li‐ions’ trajectory. X‐Ray photoelectron spectroscopy complemented with the high lateral resolution of X‐ray photoemission electron microscopy disclosed the formation of a thin layer of LiF homogenously distributed across the LTO electrode, which partially dissolves (or decomposes) upon discharge. The degradation of the PVDF and the deposition and dissolution (and/or decomposition) of the LiF layer continue over subsequent charge and discharge cycles. The process is augmented when the cycling temperature is increased to 80 °C. The results shown in this work are crucial to interpret electrochemical data, such as specific charge decay or impedance rise, and have relevance for all PVDF‐based electrodes, especially when employed in high‐voltage battery cells where the more extreme cycling conditions exacerbate electrode components’ stability.
From Spontaneous to Photo‐Triggered and Photo‐Calibrated Nitric Oxide Donors
Authors: Zhang Ziqian , Luo Xiao , Yang Youjun
Published: November 2020

NO donors have found wide medical use long before the biorelevance of nitric oxide (NO) was unveiled. From glyceryl trinitrate, amyl nitrite and nitroprusside, to nitrosothiols, NONOates and more, a wide variety of chemicals have been employed as nitric oxide donors for treating pathological conditions and investigating the NO biology. Yet, the release kinetics of these classic NO donors are hard‐to‐define and hard‐to‐monitor in biological milieu. Novel NO donors with robustly defined NO release profiles are sought after. These endeavours have introduced a plethora of novel NO donors, including stimulus‐triggered NO donors, fluorophore‐labeled NO donors. The field also sees a recent addition, i. e. photo‐triggered and photo‐calibrated NO donors, whose NO release is photo‐controlled and further accompanied by a fluorescence turn‐on as a built‐in calibration mechanism of NO release. This review provides an overview of the NO biochemistry, as a roadmap for the chemistry of NO donors. The design rationale and the release mechanism of different classes of NO donors were discussed. Some interesting and notable applications were briefly discussed, e. g. super‐resolution localization microscopic imaging of cell structures, and photo‐acoustic probes for disease diagnosis. With joint‐force, these NO donors constitutes a group of indispensable molecular tools of chemical biology and medicine in real applications.
Structure, catalysis, and inhibition mechanism of prenyltransferase
Authors: Chang Hsin‐Yang , Cheng Tien‐Hsing , Wang Andrew H.‐J.
Published: November 2020

Isoprenoids, also known as terpenes or terpenoids, represent a large family of natural products composed of five‐carbon isopentenyl diphosphate or its isomer dimethylallyl diphosphate as the building blocks. Isoprenoids are structurally and functionally diverse and include dolichols, steroid hormones, carotenoids, retinoids, aromatic metabolites, the isoprenoid side‐chain of ubiquinone, and isoprenoid attached signaling proteins. Productions of isoprenoids are catalyzed by a group of enzymes known as prenyltransferases, such as farnesyltransferases, geranylgeranyltransferases, terpenoid cyclase, squalene synthase, aromatic prenyltransferase, and cis‐ and trans‐prenyltransferases. Because these enzymes are key in cellular processes and metabolic pathways, they are expected to be potential targets in new drug discovery. In this review, six distinct subsets of characterized prenyltransferases are structurally and mechanistically classified, including (1) head‐to‐tail prenyl synthase, (2) head‐to‐head prenyl synthase, (3) head‐to‐middle prenyl synthase, (4) terpenoid cyclase, (5) aromatic prenyltransferase, and (6) protein prenylation. Inhibitors of those enzymes for potential therapies against several diseases are discussed. Lastly, recent results on the structures of integral membrane enzyme, undecaprenyl pyrophosphate phosphatase, are also discussed.
Ca2+‐regulated cell migration revealed by optogenetically engineered Ca2+ oscillations
Authors: Lai Yi‐Shyun , Chang Ya‐Han , Chen Yong‐Yi , Xu Jixuan , Yu Chi‐Sian , Chang Su‐Jing , Chen Pai‐Sheng , Tsai Shaw‐Jenq , Chiu Wen‐Tai
Published: November 2020

The ability of a single Ca2+ ion to play an important role in cell biology is highlighted by the need for cells to form Ca2+ signals in the dimensions of space, time, and amplitude. Thus, spatial and temporal changes in intracellular Ca2+ concentration are important for determining cell fate. Optogenetic technology has been developed to provide more precise and targeted stimulation of cells. Here, U2OS cells overexpressing Ca2+ translocating channelrhodopsin (CatCh) were used to mediate Ca2+ influx through blue light illumination with various parameters, such as intensity, frequency, duty cycle, and duration. We identified that several Ca2+‐dependent transcription factors and certain kinases can be activated by specific Ca2+ waves. Using a wound‐healing assay, we found that low‐frequency Ca2+ oscillations increased cell migration through the activation of NF‐κB. This study explores the regulation of cell migration by Ca2+ signals. Thus, we can choose optical parameters to modulate Ca2+ waves and achieve activation of specific signaling pathways. This novel methodology can be applied to clarify related cell‐signaling mechanisms in the future.
Myosteatosis rather than sarcopenia associates with non‐alcoholic steatohepatitis in non‐alcoholic fatty liver disease preclinical models
Authors: Nachit Maxime , De Rudder Maxime , Thissen Jean‐Paul , Schakman Olivier , Bouzin Caroline , Horsmans Yves , Vande Velde Greetje , Leclercq Isabelle Anne
Published: November 2020

Background

Non‐alcoholic fatty liver (NAFL) disease (NAFLD) is the most common chronic liver disease in the world. While most subjects have ‘inert’ NAFL, a subset will progress to non‐alcoholic steatohepatitis (NASH) and its life‐threatening complications. A substantial body of literature supports that a low muscle mass, low strength, and/or muscle fatty infiltration (myosteatosis) are associated with NAFLD severity. Here, we evaluated the muscle compartment in NASH preclinical models to decipher the kinetics of muscle alterations in relation with liver disease progression.

Methods

We developed and validated a micro‐computed tomography‐based methodology to prospectively study skeletal muscle mass and density in muscle and liver (i.e. reflecting fatty infiltration) in a high‐throughput and non‐invasive manner in three preclinical NAFLD/NASH rodent models: fat aussie (FOZ) mice fed a high‐fat diet (FOZ HF), wild‐type (WT) mice fed a high‐fat high‐fructose diet (WT HFF), and WT mice fed a high‐fat diet (WT HF). We compared them with WT mice fed a normal diet (WT ND) used as controls.

Results

‐FOZ HF with fibrosing NASH had sarcopenia characterized by a reduced muscle strength when compared with WT HF and WT HFF with early NASH and WT ND controls (165.2 ± 5.2 g vs. 237.4 ± 11.7 g, 256 ± 5.7 g, and 242.9 ± 9.3 g, respectively, P 60; 0.001). Muscle mass or strength was not lower in FOZ HF, WT HF, and WT HFF with early NASH than in controls. Myosteatosis was present in FOZ HF with fibrosing NASH, but also in FOZ HF, WT HF, and WT HFF with early NASH (muscle density = 0.50 ± 0.02, 0.62 ± 0.02, 0.70 ± 0.05, and 0.75 ± 0.03, respectively, with P 60; 0.001 when compared with respective controls). Myosteatosis degree was strongly correlated with NAFLD activity score (r = −0.87, n = 67, P 60; 0.001). In multivariate analysis, the association between myosteatosis and NASH was independent from homeostatic model assessment of insulin resistance and visceral fat area (P 60; 0.05). Myosteatosis degree powerfully discriminated NASH from benign NAFL and normal liver (area under the receiver operating characteristic = 0.96, n = 67, P 60; 0.001).

Conclusions

Taken together, our data support that there is no sarcopenia in obese mice with early NASH. In contrast, the severity of myosteatosis reflects on hepatocellular damage and inflammation during early NASH development. This observation prompts us to exploit myosteatosis as a novel non‐invasive marker of NASH.
Mo‐doped TiO2 using plasma in contact with liquids: advantages and limitations
Authors: Khlyustova Anna , Sirotkin Nikolay , Kraev Anton , Kusova Tatiana , Titov Valery , Agafonov Alexander
Published: November 2020

BACKGROUND

The presented work focuses on the comparison of sorption and photocatalytic properties of TiO2 doped with molybdenum using different methods of Mo loading. The structural and photocatalytic characteristics of doped TiO2 are determined by the method of synthesis and loading of the dopant element. As an alternative to simple wet chemical loading, three types of low‐temperature plasma in contact with liquid are considered: atmospheric pressure glow discharge, underwater diaphragm discharge, and underwater plasma.

RESULTS

The results show that the introduction of Mo, regardless of the doping method, leads to a decrease in the band gap. The surface characteristics of powders depend on the doping method. The sorption capacity increases two to three times, and the efficiency of photodestruction increases from 52% to 96% when exposed to visible light for 60 min.

CONCLUSIONS

A comparison of the sorption and photocatalytic activity of Mo‐doped TiO2 showed the inexpediency of using a glow discharge for doping. The synthesis of a highly efficient sorbent or photocatalyst can be determined by the type of underwater plasma. © 2020 Society of Chemical Industry
“I don't think the problem's the student…I think it's us”: Engaging faculty in curriculum innovation
Authors: Kornegay Elizabeth C. , Jackson Tate H. , LaGarry‐Cahoon Alison , Reside Jonathan M. , Wolcott Michael D. , Quinonez Rocio B.
Published: November 2020

Purpose

The need to innovate predoctoral dental education is well established; however, there are few recent reports to guide substantial curriculum transformation. The purpose of this study was to describe faculty perspectives on their vision of future graduates, curriculum needs, and potential barriers to a successful redesign. This information would be used to inform strategic planning for the predoctoral curriculum transformation.

Methods

Eighty full‐time faculty from the University of North Carolina Adams School of Dentistry participated in 60‐minute focus groups in March 2018. Focus group questions were developed to elicit perceptions about the current curriculum, what the dental graduate should know in 2040, and what is needed to engage faculty in curriculum change. Transcripts of the focus group sessions were analyzed by a third‐party research group using qualitative thematic analysis to identify pertinent themes shared by participants.

Results

Faculty identified that developing clinical skill that engages multiple specialties, student time to engage in advocacy activities, and opportunities to integrate biomedical, clinical, and behavioral sciences as critical features of the curriculum. They believed the 2040 graduate should be able to critically evaluate literature, exhibit strong leadership skills, and adapt to the changing healthcare environment. To better engage faculty in curriculum change, there needs to be dedicated time, sufficient resources, a clear plan, and greater collaboration across the school.

Conclusion

When embarking on curriculum transformation, engagement with faculty is a critical component of the change process. Focus groups can be used as a technique to better understand faculty perspectives about curricular needs and the overall vision.
Communication about positive BRCA1 and BRCA2 genetic test results and uptake of testing in relatives in a diverse Asian setting
Authors: Lee Daphne S.‐C. , Meiser Bettina , Mariapun Shivaani , Hassan Tiara , Yip Cheng‐Har , Mohd Taib Nur A. , Teo Soo‐Hwang , Thong Meow‐Keong , Yoon Sook‐Yee
Published: November 2020

The vast majority of studies assessing communication of BRCA1/2 results with relatives and family uptake of BRCA1/2 testing have been conducted in Western societies, and a dearth of studies have been conducted in Asia among relatives of diverse carriers of pathogenic BRCA1/2 germline variants. This study aimed to present rates of BRCA1/2 result disclosure by probands and probands’ motivators and barriers of family communication and predictive testing uptake among eligible relatives. It also examined patterns of disclosure and testing uptake among different types of relatives. Eighty‐seven carriers with either breast or ovarian cancer, who had previously been found to be carriers of a pathogenic variant in BRCA1/2, were interviewed over the phone using a semi‐structured interview guide. Fifty‐six percent of patients were Chinese, 21% were Indian, and 23% were Malay. It was found that 62.0% of eligible first‐ and second‐degree relatives were informed by the proband about the testing result and that 11.5% of eligible first‐ and second‐degree relatives had genetic testing. First‐degree relatives were more likely to have been informed and tested compared to second‐degree relatives, as were sisters compared to brothers. The low rates of family communication and testing uptake documented in this study suggest that interventions should focus on encouraging probands to inform male and second‐degree relatives and targeting such relatives to increase informed decisions and accessibility to testing. Promotion strategies should be culturally sensitive to optimize outcomes.
Deficit of Cross‐Frequency Integration in Mild Cognitive Impairment and Alzheimer's Disease: A Multilayer Network Approach
Authors: Wang Xiaoyue , Cui Xiaohong , Ding Congli , Li Dandan , Cheng Chen , Wang Bin , Xiang Jie
Published: November 2020

Background

Studies at specific frequencies have shown abnormalities in brain functional networks among mild cognitive impairment (MCI) and Alzheimer's disease (AD) patients. Previous studies have failed to take into account the possibility that optimal cognitive integration requires interactions between different frequency bands.

Purpose

To study whether there is abnormal cross‐frequency integration in patients' brains during disease progression.

Study Type

Retrospective.

Population

Forty‐six normal control (NC), 85 patients withMCI,and 31 patients withAD.

Field Strength/Sequence

3T.

Assessment

Multilayer network models were constructed for NC, MCI, and AD, and multilayer participation coefficient (MPC) was used to study the changes of the interlayer relationship in the course of disease development. In addition, MPC and an overlapping degree were combined to classify nodes in the network, and the role of key nodes in the interlayer interaction was mainly observed. Finally, the correlation between multilayer network measures and cognitive function was investigated.

Statistical Tests

Pearson chi‐squared two‐tailed test, one‐way analysis of variance (ANOVA), nonparametric Spearman correlation coefficientr, and the false discovery rate.

Results

The MPC of the network decreased significantly in MCI (P < 0.05) and AD (P < 0.05). The number of intralayer nodes increased significantly (MCI [P < 0.05], AD [P < 0.05]) and the number of interlayer nodes decreased significantly. Centrality loss between frequencies of a large number of hub nodes, among which the damaged hub nodes included the left hippocampus, left precuneus, right precuneus, left posterior cingulate gyrus, left precentral gyrus, right precentral gyrus, left medial superior frontal gyrus, and right postcentral gyrus. MPC was significantly associated with memory impairment in patients (AD [Spearman'sr =0.526,P < 0.05], MCI [Spearman'sr =0.229,P < 0.05]), and these related regions included damaged hub nodes in patients.

Data Conclusion

In the multilayer networks of patients, there was an obvious deficit in cross‐frequency integration and the hub nodes were preferentially damaged. Moreover, these vulnerable hubs are associated with patients' cognitive scores.

Level of Evidence

1

Technical Efficacy Stage

3
Using Bayesian statistics to detect trends in Alaskan precipitation
Authors: White James H.R. , Walsh John E. , Thoman Richard L.
Published: November 2020

Air temperature has exhibited a clear positive trend over the past several decades throughout the arctic, including Alaska. Other variables, such as precipitation, have much more uncertain trends due to inhomogeneities in measurement and high internal variability. The use of linear regression to analyse precipitation in Alaska has resulted in often contradictory results. This paper proposes the use of Bayesian models such as the R package Rbeast to allow for the more nuanced analysis. The examples given in this paper show how Bayesian analysis can be used to detect subtle changes and better constrain the disagreement between data sources. Applied to gridded data, Bayesian analysis shows how precipitation has changed overtime across Alaska. Change has accelerated over the past decade, but only precipitation increase on the North Slope can be assigned high confidence. Overall, this analysis highlights how Bayesian techniques may be uniquely useful to climate research in regions with heterogeneous data sources and substantial internal variability.
Electrospun biodegradable poly(ε‐caprolactone) membranes for annulus fibrosus repair: Long‐term material stability and mechanical competence
Authors: Alexeev Dmitriy , Tschopp Melanie , Helgason Benedikt , Ferguson Stephen J.
Published: November 2020

Background

Electrospun (ES) poly(ɛ‐caprolactone) (PCL) is widely used to provide critical mechanical support in tissue engineering and regenerative medicine applications. Therefore, there is a clear need for understanding the change in the mechanical response of the membranes as the material degrades in physiological conditions.

Study Design

ES membranes with fiber diameters from 1.6 to 6.7 μm were exposed to in vitro conditions at 37°C in Dulbecco's modified Eagle's medium (DMEM) or dry for up to 6 months.

Methods

During this period, the mechanical properties were assessed using cyclic mechanical loading, and material properties such as crystallinity and ester bond degradation were measured.

Results

No significant difference was found for any parameters between samples kept dry and in DMEM. The increase in crystallinity was linear with time, while the ester bond degradation showed an inverse logarithmic correlation with time. All samples showed an increase in modulus with exposure time for the first loading cycle. Modulus changes for the consecutive loading cycles showed a nonlinear relationship to the exposure time that depended on membrane type and maximum strain. In addition, the recovered elastic range showed an expected increase with the maximum strain reached. The mechanical response of ES membranes was compared to experimental tensile properties of the human annulus fibrosus tissue and an in silico model of the intervertebral disk. The modulus of the tested membranes was at the lower range of the values found in literature, while the elastically recoverable strain after preconditioning for all membrane types lies within the desired strain range for this application.

Conclusion

The long‐term assessment under application‐specific conditions allowed to establish the mechanical competence of the electrospun PCL membranes. It can be concluded that with the use of appropriate fixation, the membranes can be used to create a seal on the damaged AF.
Role of gas chromatography and olfactometry to understand the wine aroma: Achievements denoted by multidimensional analysis
Authors: Welke Juliane Elisa , Hernandes Karolina Cardoso , Nicolli Karine Primieri , Barbará Janaína Aith , Biasoto Aline Camarão Telles , Zini Claudia Alcaraz
Published: November 2020

The human nose has been used as a detector in gas chromatography analysis to evaluate odoriferous compounds related to aroma and quality of wine. Several olfactometric techniques are available to access the description, intensity, and/or duration of the odor of each compound. Olfactometry can be associated with one‐dimensional gas chromatography or multidimensional gas chromatography, including heart‐cut gas chromatography and comprehensive two‐dimensional gas chromatography. Multidimensional gas chromatography may help to resolve coeluted compounds and detect important trace components for the aroma. The identification of odor‐active compounds may help to differentiate wines according to terroir, grapes cultivars used in winemaking or types of aging, understand the role of fungal infection of grapes for wine quality, find the best management practices in vineyard and vinification to obtain the greatest quality. In addition, when the instrumental techniques are combined with sensory analysis, even more accurate information may be obtained regarding the overall wine aroma. This review discloses the state of the art of olfactometric methods and the analytical techniques used to investigate odor‐active compounds such as one‐dimensional gas chromatography, multidimensional gas chromatography, and comprehensive two‐dimensional gas chromatography. The advances in knowledge of wine aroma achieved with the use of these techniques in the target and profiling approaches were also discussed.
Diatoms rapidly alter sinking behavior in response to changing nutrient concentrations
Authors: Du Clos Kevin T. , Karp‐Boss Lee , Gemmell Brad J.
Published: November 2020

A diatom's sinking speed affects its depth in the water column, which determines its access to light and nutrients. Some large, centric diatom species perform an unsteady sinking behavior in which a cell's sinking speed oscillates over more than an order of magnitude on time scales of seconds. Diatoms are known to decrease mean sinking speeds and the magnitude of unsteady sinking following exposure to nutrient replete conditions over hours to days. Here we show that on shorter time scales of minutes to hours, nutrient deprived Coscinodiscus wailesii cells increase the mean and unsteadiness of their sinking when exposed to increased nutrient concentrations. Cultures exposed to nitrate or silicate‐depleted media followed by a spike of the missing nutrient showed a sinking speed increase within the first 2 h that declined over the next 22 h. Phosphate deprived cultures did not respond similarly to a phosphate spike. In an experiment with an artificial nutricline in which cells encountered a sharp increase in nutrient concentrations over a distance of 10 cm, mean sinking speeds increased eight fold, and sinking unsteadiness increased significantly; these sinking speed changes occurred over 33 min. The contrasting short and long‐term sinking behavior responses seen in this study demonstrates the importance of examining sinking behavior over multiple time scales. Initial fast and unsteady sinking upon encountering increasing nutrient concentrations may help diatoms take advantage of patchy nutrient distributions. Longer term, slow and steady sinking may be beneficial for maximizing light exposure and minimizing energy costs from unsteady sinking.
Atmospheric stilling and warming air temperatures drive long‐term changes in lake stratification in a large oligotrophic lake
Authors: Stetler Jonathan T. , Girdner Scott , Mack Jeremy , Winslow Luke A. , Leach Taylor H. , Rose Kevin C.
Published: November 2020

Lake surface temperatures are warming in many regions and have the potential to alter seasonal thermal stratification. However, the effects of climate change on thermal stratification can be difficult to characterize because trends in thermal stratification can be regulated by changes in multiple climate variables and other characteristics, such as water clarity. Here, we use long‐term (1993–2017) data from near‐pristine Crater Lake (Oregon) to understand long‐term changes in the depth and strength of summer stratification, measured by the center of buoyancy and Schmidt Stability, respectively. The depth of stratification has shoaled significantly (2.4 m decade−1), while stratification strength exhibited no long‐term trend. Empirical observations and modeling scenarios demonstrate that atmospheric stilling at Crater Lake is associated with the 25‐year shoaling trend as spring wind speeds declined over the observation period. While summer lake surface water and air temperatures warmed during the study period, spring air temperatures were variable and correlated with summer Schmidt Stability. Our results indicate that warmer spring air temperature resulted in earlier onset of stratification and stronger summer stratification. The observed shoaling of stratification depth at Crater Lake may have important ecological consequences, especially for non‐motile primary producers who can become constrained within a thinner epilimnion and exposed to higher solar radiation and reduced upwelling of nutrients. Driven by climate changes, many large lakes may be experiencing similar trends in seasonal stratification.
Drivers and projections of ice phenology in mountain lakes in the western United States
Authors: Caldwell Timothy J. , Chandra Sudeep , Albright Thomas P. , Harpold Adrian A. , Dilts Thomas E. , Greenberg Jonathan A. , Sadro Steve , Dettinger Michael D.
Published: November 2020

Climate change is causing rapid warming and altered precipitation patterns in mountain watersheds, both of which influence the timing of ice breakup in mountain lakes. To enable predictions of ice breakup in the future, we analyzed a dataset of mountain lake ice breakup dates derived from remote sensing and historical downscaled climate data. We evaluated drivers of ice breakup, constructed a predictive statistical model, and developed projections of mountain lake ice breakup date with global climate models. Using Random Forest analysis, we determined that winter and spring cumulative snow fraction (portion of precipitation falling as snow) and air temperature are the strongest predictors of ice breakup on mountain lakes. Interactions between precipitation, cumulative winter air temperature and lake surface area indicate that shifts in air temperature and precipitation affect smaller lakes (< 2 km2) more than larger lakes (> 2–10 km2). A linear mixed effects model (RMSE of 18 d), applied with an ensemble of 15 global climate models, projected that end‐of‐century ice breakup in mountain lakes will be earlier by 25 ± 4 and 61 ± 5 (mean ± SE) days for representative concentration pathways 4.5 and 8.5, respectively.
Addressing the Covid‐19 pandemic and future public health challenges through global collaboration and a data‐driven systems approach
Authors: Ros Francisco , Kush Rebecca , Friedman Charles , Gil Zorzo Esther , Rivero Corte Pablo , Rubin Joshua C. , Sanchez Borja , Stocco Paolo , Van Houweling Douglas
Published: November 2020

Covid‐19 has already taught us that the greatest public health challenges of our generation will show no respect for national boundaries, will impact lives and health of people of all nations, and will affect economies and quality of life in unprecedented ways. The types of rapid learning envisioned to address Covid‐19 and future public health crises require a systems approach that enables sharing of data and lessons learned at scale. Agreement on a systems approach augmented by technology and standards will be foundational to making such learning meaningful and to ensuring its scientific integrity. With this purpose in mind, a group of individuals from Spain, Italy, and the United States have formed a transatlantic collaboration, with the aim of generating a proposed comprehensive standards‐based systems approach and data‐driven framework for collection, management, and analysis of high‐quality data. This framework will inform decisions in managing clinical responses and social measures to overcome the Covid‐19 global pandemic and to prepare for future public health crises. We first argue that standardized data of the type now common in global regulated clinical research is the essential fuel that will power a global system for addressing (and preventing) current and future pandemics. We then present a blueprint for a system that will put these data to use in driving a range of key decisions. In the context of this system, we describe and categorize the specific types of data the system will require for different purposes and document the standards currently in use for each of these categories in the three nations participating in this work. In so doing, we anticipate some of the challenges to harmonizing these data but also suggest opportunities for further global standardization and harmonization. While we have scaled this transnational effort to three nations, we hope to stimulate an international dialogue with a culmination of realizing such a system.
Modeling and analyzing the effects of fixed‐time intervention on transmission dynamics of echinococcosis in Qinghai province
Authors: Zhang Yunhu , Xiao Yanni
Published: November 2020

In this study, we propose a mathematical model with periodic transmission and impulsive interventions to describe the transmission dynamics of echinococcosis in multiple hosts and to explore the efficacy of control and prevention measures. Our model includes the life cycle of Echinococcus in dog population (stray dogs and domestic dogs), contaminated environment, and human population to gain new biological insight. Note that different control strategies on stray and domestic dog populations may lead to inconsistency in the impulsive periods and system itself period, which brings great challenges in analyzing the proposed periodic system with multiple pulses. We theoretically examined the threshold dynamics, uniform persistence of disease on the basis of basic reproduction number. In particular, we define the basic reproduction number for stray and domestic dog population and obtain the globally asymptotical stability of the disease‐free periodic solutions. We further obtain that echinococcosis may persist in human population if it persists in any dog population. Numerical simulations show that increasing the delivery rate and frequency of anthelmintics in domestic dogs and increasing the culling intensity and frequency in wild dogs could greatly reduce the disease incidence in two populations, respectively. The findings suggest that culling measures on wild dog population and environmental hygiene are crucial strategies in the control of the spread of echinococcosis in human being.
Solving Steiner trees: Recent advances, challenges, and perspectives
Authors: Ljubić Ivana
Published: November 2020

The Steiner tree problem (STP) in graphs is one of the most studied problems in combinatorial optimization. Since its inception in 1970, numerous articles published in the journal Networks have stimulated new theoretical and computational studies on Steiner trees: from approximation algorithms, heuristics, metaheuristics, all the way to exact algorithms based on (mixed) integer linear programming, fixed parameter tractability, or combinatorial branch‐and‐bounds. The pervasive applicability and relevance of Steiner trees have been reinforced by the recent 11th DIMACS Implementation Challenge in 2014 and the PACE 2018 Challenge. This article provides an overview of the rich developments from the last three decades for the STP in graphs and highlights the most recent computational studies for some of its closely related variants.
A Lagrangian approach for the minimum spanning tree problem with conflicting edge pairs
Authors: Carrabs Francesco , Gaudioso Manlio
Published: November 2020

This article addresses the minimum spanning tree problem with conflicting edge pairs, a variant of the classical minimum spanning tree where, given a list of conflicting edges, the goal is to find the cheapest spanning tree with no edges in conflict. We adopt a Lagrangian relaxation approach together with a dual ascent and a subgradient procedure to find tight lower bounds on the optimal solution. The algorithm is also equipped with a heuristic approach which provides an upper bound by removing the conflicts from possible infeasible solutions met during the calculation of the lower bounds. The computational results, carried out on benchmark instances, show that the proposed algorithm finds the optimal solutions on several instances. Moreover, the lower bounds it provides are much more accurate than ones provided by other Lagrangian approaches available in the literature and they are computed in much less time.
Perceptions of ambulance nurses on their knowledge and competence when assessing psychiatric mental illness
Authors: Todorova Lizbet , Johansson Anders , Ivarsson Bodil
Published: November 2020

Aims and objectives

To obtain the current perception of the knowledge and competence of pre‐hospital emergency specialist nurses (ambulance) in attending patients with psychiatric symptoms.

Background

Psychiatric illnesses have increased throughout the population. Consequently, pre‐hospital emergency services frequently attend individuals with suspected or known mental illnesses.

Design

We employed a set of quantitative and qualitative methods to gain a deeper understanding of ambulance nurses' self‐evaluated knowledge.

Methods

Seven ambulance nurses received and completed a survey questionnaire prior commencing employment in November 2019. Then, we conducted interviews to explore ambulance nurses' perceptions of their own knowledge and competence when attending individuals with mental disorders. The surveys were analysed with descriptive statistics, followed by content analysis.

Results

Three topics emerged: the encounter of patients with mental illness; the awareness of lacking knowledge about mental illnesses; and the expectations for future Prehospital Emergency Psychiatric Response Teams. Although ambulance nurses already possessed basic knowledge regarding psychiatric illnesses, it was insufficient, based on their perception of appropriate care. Ambulance nurses considered that combining pre‐hospital and psychiatric expertise in the pre‐hospital emergency unit would increase their in‐depth knowledge about various psychiatric illnesses, the treatment options and the alternatives regarding where to deliver patients for continued care.
Hall and ion slip effects on magnetohydrodynamic convective rotating flow of Jeffreys fluid over an impulsively moving vertical plate embedded in a saturated porous medium with Ramped wall temperature
Authors: Krishna M. Veera , Chamkha Ali J.
Published: November 2020

In the present study, it is explored theoretically Hall and ion slip effects on the unsteady magnetohydrodynamic (MHD) rotating flow of a viscous, incompressible electrically conducting, and optically thick radiating Jeffreys fluid over an impulsively, moving vertical plate embedded in a saturated porous medium, when the temperature of the plate has a provisionally ramped profile. The exact solutions of the governing equations for the flow domain are attained by making use of the Laplace transform method. The specified analytical solutions are also acquired for some limiting cases. The research phrases of engineering curiosity for skin friction and Nusselt number are originated for both ramped wall temperature and the isothermal plate. Sherwood number is also obtained. The numerical results of velocity, temperature, and concentration distributions are exhibited graphically whereas skin friction, Nusselt number, and also Sherwood number are mentioned in a table form. It is observed that on either cases of ramped wall temperature and isothermal plate, the resultant velocity enhances with an increase in Hall and ion slip parameters. Reversal behavior is observed with an increase in magnetic field parameter, Jeffreys fluid parameter and Prandtl number. Thermal and concentration buoyancy forces and thermal radiation tend to accelerate the resultant velocity throughout the boundary layer region. The temperature reduces with an increase in Prandtl number and reverse effect is observed with an increase in thermal radiation parameter. Mass diffusion tends to enhance to species concentration. The rotation and Jeffreys fluid parameters tend to enhance both stress components. Nusselt number enables to lessen with growing in thermal radiation parameter and is magnified on escalating in time. The Sherwood number is improved with increasing in Schmidt number at the plate and it is refused on increasing in time.
Emphasis on unsteady dynamics of bioconvective hybrid nanofluid flow over an upward–downward moving rotating disk
Authors: Jayadevamurthy Punith Gowda Ramanahalli , Rangaswamy Naveen kumar , Prasannakumara Ballajja Chandrappa , Nisar Kottakkaran Sooppy
Published: November 2020

The fluid flow between the rotating disk has wide range of applications and are used in medical equipment's, car brake system, gas turbines, manufacturing of glass and plastic films. Inspired from these applications, we scrutinized the behavior of an axisymmetric expansion–contraction rotating disk on three‐dimensional flow of hybrid nanoparticles in the presence of microorganisms. Here, we considered copper and silica nanoparticles suspended in base fluid water. It is known that, the inequality of concentration in chemically reactive species affecting mass transfer mechanism and activation energy plays an important role in increasing the production speed of chemical reactions. Hence, the Arrhenius activation energy and chemical reaction effects are added in the mass equation. Autorelated transformations were adopted to reduce PDE's to ODE's and then, we utilized the RKF‐45 by adopting shooting skill to solve reduced ODE's. The analysis of rate of heat and mass transfer is done through graphs. Furthermore, change in velocity, thermal and concentration profiles for various nondimensional parameters are deliberated briefly by using suitable plots. Result reveals that rise in wall expansion/contraction parameter supports up the velocity gradients, higher the values of bioconvection Peclet number and concentration difference parameter declines the microorganism profile and Nusselt number decreases for rise in values of thermophoresis parameter.
Heat and mass transfer analysis for bioconvective flow of Eyring Powell nanofluid over a Riga surface with nonlinear thermal features
Authors: Usman   , Khan M. Ijaz , Shah Faisal , Khan Sami Ullah , Ghaffari Abuzar , Chu Yu‐Ming
Published: November 2020

This study aims to explore the rheological consequences of Eyring Powell nanofluid along with the swimming characteristics of gyrotactic microorganisms over the surface of the Riga plate which is embedded in a porous medium. The bioconvection fluid flow phenomenon in the presence of perpendicularly applied magnetic field is investigated. The effects of nonlinear thermal radiation, heat source/sink, and activation energy subject to convective‐Nield boundary conditions are utilized in energy and concentration equations. A precise similarity transformation helps us to transform governing partial differential equations into ordinary differential equations and then numerically tackled through a well‐known shooting method. The upshots of several pertinent parameters upon the dimensionless profiles of velocity, temperature, concentration, and microorganisms are scrutinized. The heat as well as mass transfer rates and local density number are also calculated. To show the accuracy of the adopted numerical scheme a tabular comparison in limiting case is made between the present results and the results from the literature. Finally, the current study tells us that the pertinent parameters have produced a significant influence on the boundary layer profiles.
A Phase II Study of Fulvestrant 500 mg as Maintenance Therapy in Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Patients with Advanced Breast Cancer After First-Line Chemotherapy
Authors: Xu Fei , Zheng Qiufan , Xia Wen , Ouyang Quchang , Pang Danmei , Yuan Zhongyu , Shi Yanxia , Peng Roujun , Lu Qianyi , Wang Shusen
Published: November 2020

Lessons Learned

Fulvestrant 500 mg maintenance therapy showed a clinical benefit rate of 76% and median progression-free survival of 16.1 months in patients who achieved objective responses or disease control after first-line chemotherapy. Adverse events with fulvestrant maintenance therapy were consistent with the known safety profile of the drug.

Background

Evidence for maintenance hormonal therapy after chemotherapy for estrogen receptor (ER)–positive/human epidermal growth factor receptor 2 (HER2)–negative advanced breast cancer is scarce. This study aimed to evaluate the efficacy of fulvestrant 500 mg maintenance therapy in patients after first-line chemotherapy.

Methods

We enrolled postmenopausal women with ER-positive/HER2-negative advanced breast cancer who attained tumor responses or disease control with four to eight cycles of chemotherapy as first-line treatment. Fulvestrant 500 mg was injected on days 1, 15, and 29 and every 28 (±3) days thereafter. The primary endpoint was the clinical benefit rate (CBR); the secondary endpoints included the objective response rate (ORR), progression-free survival (PFS), and safety.

Results

We included 58 patients; the median follow-up duration was 32.6 months. The CBR since commencing fulvestrant maintenance therapy was 76% (95% confidence interval [CI], 63%–86%), and ORR was 14% (95% CI, 6%–25%); eight patients achieved partial response. The median PFS for fulvestrant maintenance therapy was 16.1 months (95% CI, 10.3–21.0 months). Thirty-nine patients (67%) reported at least one adverse event, of which most were grade 1/2, whereas three patients (5%) reported grade 3 adverse events.

Conclusion

Fulvestrant 500 mg is a feasible and promising hormonal maintenance strategy in patients with ER-positive/HER2-negative advanced breast cancer who have no disease progression after first-line chemotherapy.
Long‐Term Colloidally Stable Aqueous Dispersions of ≤5 nm Spinel Ferrite Nanoparticles
Authors: Eckardt Mirco , Thomä Sabrina L. J. , Dulle Martin , Hörner Gerald , Weber Birgit , Förster Stefan , Zobel Mirijam
Published: November 2020

Applications in biomedicine and ferrofluids, for instance, require long‐term colloidally stable, concentrated aqueous dispersions of magnetic, biocompatible nanoparticles. Iron oxide and related spinel ferrite nanoparticles stabilized with organic molecules allow fine‐tuning of magnetic properties via cation substitution and water‐dispersibility. Here, we synthesize≤5 nm iron oxide and spinel ferrite nanoparticles, capped with citrate, betaine and phosphocholine, in a one‐pot strategy. We present a robust approach combining elemental (CHN) and thermal gravimetric analysis (TGA) to quantify the ratio of residual solvent molecules and organic stabilizers on the particle surface, being of particular accuracy for ligands with heteroatoms compared to the solvent. SAXS experiments demonstrate the long‐term colloidal stability of our aqueous iron oxide and spinel ferrite nanoparticle dispersions for at least 3 months. By the use of SAXS we approved directly the colloidal stability of the nanoparticle dispersions for high concentrations up to 100 g L−1.
Warranty assessment of photovoltaic modules based on a degradation probabilistic model
Authors: Prieto‐Castrillo Francisco , Núñez Neftalí , Vázquez Manuel
Published: November 2020

Evaluating the probability of failure of a product during the warranty is key to estimating the cost of its entire life cycle. Photovoltaic (PV) modules are the most reliable elements of a PV system, and their high reliability translates into long warranty periods (typically 25 to 30 years). The number of PV modules that fail during warranty and when they failed is an important issue to estimate the life cycle cost of PV modules. In this paper, we propose a coupled degradation‐warranty model for PV modules. The proposed model is aimed to assess the probability of failure over time covered by warranty based on degradation data. This allows us to estimate the time of PV modules failure covered by the warranty. Although the warranty model has been applied to some forms of degradation and sales functions, our method can be applied to any real application. This allows the key parameters of the warranty to be obtained in a simple way. The required degradation parameters to fulfill warranty depend on the allowable ratio of warranted elements. However, the main conclusion of the influence of degradation rates on warranty is that it is not possible to fulfill 25 years of warranty if degradation rates are larger than 0.8%/year. The required degradation rates values, for 25 years of warranty, will be lower than 0.5%/year if the allowed warranted element is in the range of 1%.