bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytokine storm and leukocyte changes in mild versus severe SARS-CoV-2 infection: Review of 3939 COVID-19 patients in China and emerging pathogenesis and therapy concepts
Authors: Wang Jin , Jiang Mengmeng , Chen Xin , Montaner Luis J
Published: June 2020

Clinical evidence indicates that the fatal outcome observed with severe acute respiratory syndrome-coronavirus-2 infection often results from alveolar injury that impedes airway capacity and multi-organ failure—both of which are associated with the hyperproduction of cytokines, also known as a cytokine storm or cytokine release syndrome. Clinical reports show that both mild and severe forms of disease result in changes in circulating leukocyte subsets and cytokine secretion, particularly IL-6, IL-1β, IL-10, TNF, GM-CSF, IP-10 (IFN-induced protein 10), IL-17, MCP-3, and IL-1ra. Not surprising, therapies that target the immune response and curtail the cytokine storm in coronavirus 2019 (COVID-19) patients have become a focus of recent clinical trials. Here we review reports on leukocyte and cytokine data associated with COVID-19 disease in 3939 patients in China and describe emerging data on immunopathology. With an emphasis on immune modulation, we also look at ongoing clinical studies aimed at blocking proinflammatory cytokines; transfer of immunosuppressive mesenchymal stem cells; use of convalescent plasma transfusion; as well as immunoregulatory therapy and traditional Chinese medicine regimes. In examining leukocyte and cytokine activity in COVID-19, we focus in particular on how these levels are altered as the disease progresses (neutrophil NETosis, macrophage, T cell response, etc.) and proposed consequences to organ pathology (coagulopathy, etc.). Viral and host interactions are described to gain further insight into leukocyte biology and how dysregulated cytokine responses lead to disease and/or organ damage. By better understanding the mechanisms that drive the intensity of a cytokine storm, we can tailor treatment strategies at specific disease stages and improve our response to this worldwide public health threat.
Suppression of active phase voluntary wheel running in male rats by unilateral chronic constriction injury: Enduring therapeutic effects of a brief treatment of morphine combined with TLR4 or P2X7 antagonists
Authors: Green‐Fulgham Suzanne M. , Ball Jayson B. , Maier Steven F. , Rice Kenner C. , Watkins Linda R. , Grace Peter M.
Published: June 2020

The present series of studies examine the impact of systemically administered therapeutics on peripheral nerve injury (males; unilateral sciatic chronic constriction injury [CCI])‐induced suppression of voluntary wheel running, across weeks after dosing cessation. Following CCI, active phase running distance and speed are suppressed throughout the 7‐week observation period. A brief course of morphine, however, increased active phase running distance and speed throughout this same period, an effect apparent only in sham rats. For CCI rats, systemic co‐administration of morphine with antagonists of either P2X7 (A438079) or TLR4 ((+)‐naloxone) (receptors critical to the activation of NLRP3 inflammasomes and consequent inflammatory cascades) returned running behavior of CCI rats to that of shams through 5+ weeks after dosing ceased. This is a striking difference in effect compared to our prior CCI allodynia results using systemic morphine plus intrathecal delivery of these same antagonists, wherein a sustained albeit partial suppression of neuropathic pain was observed. This may point to actions of the systemic drugs at multiple sites along the neuraxis, modulating injury‐induced, inflammasome‐mediated effects at the injured sciatic nerve and/or dorsal root ganglia, spinal cord, and potentially higher levels. Given that our data to date point to morphine amplifying neuroinflammatory processes put into motion by nerve injury, it is intriguing to speculate that co‐administration of TLR4 and/or P2X7 antagonists can intervene in these inflammatory processes in a beneficial way. That is, that systemic administration of such compounds may suppress inflammatory damage at multiple sites, rapidly and persistently returning neuropathic animals to sham levels of response.
Climatology and trend analysis (1987–2016) of fire weather in the Euro‐Mediterranean
Authors: Giannaros Theodore M. , Kotroni Vassiliki , Lagouvardos Konstantinos
Published: June 2020

High‐resolution regional climate simulations were conducted for the past 30 years (1987–2016), focusing on the Euro‐Mediterranean region. The numerical simulations were used for computing the Canadian Fire Weather Index, for deriving the climatology of fire weather in the study area and investigating the presence of long‐term trends, with particular emphasis on extremes during the May to September period. Results suggest that the Euro‐Mediterranean fire weather follows a zonal pattern, characterized by adverse conditions occurring most frequently in the southern parts. Air temperature and relative humidity are the key drivers of fire weather in the study area, with precipitation and wind exerting less influence. Based on the conducted spatial trend analysis, extreme fire weather conditions have become more prevalent in the Iberian Peninsula and eastern Balkans, whereas declining trends occur in the Southeast Mediterranean basin. For both cases, the trends in fire weather extremes appear to coincide with trends in the input meteorological variables. Overall, the results of this study provide a new insight on the recent climatology and trends of fire weather in the Euro‐Mediterranean. Our dataset is publicly available on the Zenodo platform (DOI: 10.5281/zenodo.3713531).
Porphyromonas gingivalis and Alzheimer disease: Recent findings and potential therapies
Authors: Ryder Mark I.
Published: June 2020

Epidemiological studies have identified an association between periodontitis and Alzheimer disease (AD); however, the nature of this association has been unclear. Recent work suggests that brain colonization by the periodontal pathogen Porphyromonas gingivalis may link these two inflammatory and degenerative conditions. Evidence of P. gingivalis infiltration has been detected in autopsy specimens from the brains of people with AD and in cerebrospinal fluid of individuals diagnosed with AD. Gingipains, a class of P. gingivalis proteases, are found in association with neurons, tau tangles, and beta‐amyloid in specimens from the brains of individuals with AD. The brains of mice orally infected with P. gingivalis show evidence of P. gingivalis infiltration, along with various neuropathological hallmarks of AD. Oral administration of gingipain inhibitors to mice with established brain infections decreases the abundance of P. gingivalis DNA in brain and mitigates the neurotoxic effects of P. gingivalis infection. Thus, gingipain inhibition could provide a potential approach to the treatment of both periodontitis and AD.
Surface modified‐magnetic nanoparticles by molecular imprinting for the dispersive solid‐phase extraction of triazines from environmental waters
Authors: Turiel Esther , Díaz‐Álvarez Myriam , Martín‐Esteban Antonio
Published: June 2020

Magnetic nanoparticles have been surface modified by molecular imprinting and evaluated as selective sorbents for the extraction of triazines from environmental waters. The use of propazine as template allowed us to synthesize a selective material able to simultaneously recognize and selective extract not only the template but also several other herbicides of the same family. A magnetic molecularly imprinted‐based dispersive solid‐phase extraction procedure was developed and fully optimized. Magnetic molecularly imprinted polymer particles can be easily collected and separated from liquid solvents and samples with the help of an external magnetic field, avoiding in that way any centrifugation or filtration steps, which represents a remarkable advantage over traditional procedures. Under optimum conditions, selective extraction of several triazines (cyanazine, simazine, atrazine, propazine, and terbutylazine) from environmental water samples was performed prior to final determination by high‐performance liquid chromatography with diode‐array detection. Recoveries for the studied triazines were within the range of 75.2–94.1%, with relative standard deviations lower than 11.3% (n = 3). The limits of detection were within 0.16–0.51 µg/L, depending upon the triazine and the type of sample analyzed.
Let‐7b downgrades CCND1 to repress osteogenic proliferation and differentiation of MC3T3‐E1 cells: An implication in osteoporosis
Authors: Wang Li‐Juan , Cai Han‐Qing
Published: June 2020

The aim of this study was to reveal the effect of let‐7b on osteoporosis (OP). Synthetic let‐7b mimics or inhibitors were transfected into MC3T3‐E1 cells. The expression of let‐7b in MC3T3‐E1 and its effect on cell viability, apoptosis, and the apoptosis‐related proteins (Bcl‐2, Bax, and cleaved caspase‐9) were tested by CCK‐8 assay, flow cytometry and Western blot, severally. The osteogenic differentiation markers (Runx2 and Osterix) and Wnt/β‐catenin pathway related markers (β‐catenin and C‐myc) were detected by qRT‐PCR and Western blot. The relationships between let‐7b and cyclin D1 (CCND1) were confirmed by luciferase reporter assay. The differentiation and mineralization of MC3T3‐E1 cells were analyzed by alkaline phosphatase (ALP) activity assay and alizarin red staining. The outcomes indicated that overexpression/ablation of let‐7b repressed/facilitated MC3T3‐E1 cell viability and accelerated/suppressed MC3T3‐E1 cell apoptosis. Besides, a remarkable decrease/augment of Bcl‐2 protein expression and the distinct fortify/reduction of Bax and cleaved caspase‐9 expression levels were observed in let‐7b mimics/inhibitors group in MC3T3‐E1 cells. Moreover, we discovered that let‐7b overexpression/ablation retrained/facilitated the mRNA and protein expression of Runx2 and Osterix. It was confirmed that CCND1 was a downstream target of let‐7b and was negatively modulated by let‐7b. In addition, high‐expression/deficiency of let‐7b inhibited/increased the expression levels of β‐catenin and C‐myc in MC3T3‐E1 cells. Taken together, our study revealed that let‐7b overexpression/depletion repressed/accelerated MC3T3‐E1 cell proliferation, differentiation, and mineralization while promoted/suppressed MC3T3‐E1 cell apoptosis through targeting CCND1, which might be adjusted by Wnt/β‐catenin pathway. Our findings might offer a basis for developing novel targets for OP treatment.
Endoscopic Multimodal Approach to the Treatment of Airway Venous Malformations
Authors: Araslanova Rakhna , O Teresa , Waner Milton
Published: June 2020

View Video S1
Endoscopic Z‐plasty for Treatment of Supraglottic Stenosis: Experience on Nine Patients
Authors: Yılmaz Taner
Published: June 2020

Objectives

Supraglottic stenosis is a rare type of laryngeal stenosis that is caused by congenital laryngotracheal anomalies, iatrogenic instrumentation injuries, autoimmune disorders, infection, irradiation, chemical or thermal burns, and external blunt or penetrating trauma. The author presents his experience on nine patients using this new endoscopic surgical technique for treatment of supraglottic stenosis.

Study Design

Individual retrospective cohort study, tertiary referral center, university hospital.

Methods

All cases of supraglottic laryngeal stenosis treated during a 10‐year period at a tertiary academic medical center were reviewed. Nine patients with supraglottic stenosis treated with endoscopic uni‐ or bilateral z‐plasty technique were determined and presented. The etiology of stenosis was iatrogenic surgical trauma in seven patients, laryngeal fracture in one patient, and systemic lupus erythematosus in the other patient. Main outcome measures were respiratory function test results, absence of dyspnea on exertion, and decannulation if tracheotomy was present preoperatively.

Results

Seven patients with tracheotomy were decannulated 1 month after surgery. All nine patients had adequate airway and were dyspnea‐free. Their preop respiratory function test results improved significantly postoperatively (P < .05).

Conclusion

For supraglottic stenosis endoscopic surgery using mucosal flaps in the form of z‐plasty should be considered within the available surgical techniques. Although this type of surgery is highly successful, it is technically difficult to apply.

Level of Evidence

4 Laryngoscope, 131:E534–E539, 2021
Chronic rhinosinusitis in patients with cystic fibrosis—Current management and new treatments
Authors: Johnson Brian Jake , Choby Garret W. , O'Brien Erin K.
Published: June 2020

Objectives

The purpose of this article is to provide a state‐of‐the‐art review of the literature and summarize the latest publications on medical and surgical treatment of cystic fibrosis (CF) chronic rhinosinusitis (CRS), with an emphasis on describing recent advancements in cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies.

Methods

A comprehensive literature review was conducted utilizing the PubMed database with search phrases detailed within the body of the article. Abstracts were reviewed to include publications detailing medical, surgical, and CFTR modulating therapies for CF CRS. Findings from studies not previously reviewed and publications regarding CFTR modulators were emphasized.

Results

No clear guidelines for treatment of CF CRS are available. Nasal saline rinses, topical steroids, topical antibiotics, and topical dornase alfa are reported medical therapies. Ivacaftor has some sinonasal symptomatic benefit. A new triple therapy CFTR modulator, elexacaftor/tezacaftor/ivacaftor, is capable of treating 90% of patients with CF and has shown the greatest FEV1 improvement of any CFTR modulator yet. There is no clear consensus on surgical indications or technique, though aggressive surgery in recalcitrant disease has shown some symptomatic benefit. Endoscopic sinus surgery after lung transplantation may benefit some patients in whom the sinuses serve as a reservoir for recurrent pulmonary infections by decreasing rates of bronchiolitis obliterans syndrome and improving 5 year survival.

Conclusion

As lifespan increases for patients with CF, further investigation into medical therapy, CFTR modulator sinonasal outcomes, and surgical technique and outcomes for CF CRS is needed.

Level of Evidence

5.
Dynamic Optical Coherence Tomography Imaging of Telangiectasia Prior to Intense Pulsed Light Treatment—An Opportunity to Target Treatment?
Authors: Taudorf Elisabeth H. , Olsen Jonas , Lindsø Andersen Pernille , Bouazzi Dorra , Jemec Gregor B. E.
Published: June 2020

Background and Objectives

To investigate whether optical coherence tomography (OCT) could be utilized to characterize blood flow and vessel dimensions of facial telangiectasias before and during consecutive intense pulsed light (IPL) treatment.

Study Design/Materials and methods

Dynamic OCT (D‐OCT) was used to image telangiectasia immediately before and after, 1–3 days after, and 1 month after IPL treatment. Measurements included vessel width and depth, blood flow, and attenuation. Vessel dimensions at baseline were verified by a blinded observer. Clinical improvement was detected as good, moderate, or none, and adverse effects were registered at 1‐month follow‐up.

Results

In total, 14 patients with facial telangiectasia were included. At baseline, vessel width was median 0.25 mm (interquartile range [IQR]: 0.19–0.34 mm) with an intra‐class coefficient (ICC) of 0.89 (95% confidence interval [CI]: 0.70; 0.97). Vessel depth was 0.30 mm (IQR: 0.25–0.33 mm; ICC: 0.40 [CI: −0.07; 0.75]). Vessel depth increased significantly from baseline to 1‐month follow‐up (P = 0.008), whereas no significant changes in vessel width, blood flow, or attenuation were detected. Clinical efficacy seemed related to the relation between vessel dimensions and applied energy settings.

Conclusions

The D‐OCT imaging technique demonstrated that facial telangiectasias were found deeper within the skin after one IPL treatment. By characterizing the vessel dimensions and blood flow of telangiectasia, D‐OCT may improve efficacy and safety of IPL. Lasers Surg. Med. © 2020 Wiley Periodicals LLC
Apraxia of Eyelid Opening Improved by Pallidal Stimulation in Progressive Supranuclear Palsy
Authors: Orcutt Tseganesh , Vitek Jerrold , Patriat Rémi , Harel Noam , Matsumoto Joseph
Published: June 2020

View Supplementary Video 1
Measurement of solubility and diffusion coefficients of ethylene in solid and molten low‐density polyethylene with different melt indices
Authors: Jiang Binbo , Dai Jincheng , Sun Jingyuan , Ye Jian , Chen Meijuan , Han Guodong , Wang Jingdai , Yang Jian , Yang Yongrong
Published: June 2020

The diffusion behavior of ethylene in polyethylene is of great importance for the polymerization and degassing of polyethylene (PE) industry. Based on the gravimetric sorption and desorption measurement approach, an intelligent gravimetric analyzer is applied to obtain the solubility and diffusion coefficients of ethylene in solid low‐density PE (LDPE) with different melt indices at 30°C to 70°C, 0 to 4 atm and in molten LDPE at 160°C to 230°C, 0 to 4 atm, respectively. Results indicate that both the solubility and diffusion coefficients of ethylene in solid LDPE are smaller than those in molten LDPE, while the dissolution enthalpy and diffusion activation energy of ethylene in solid LDPE are higher. In addition, one‐ and two‐dimensional diffusion models are built and the effects of particle size, polymer properties, and operation conditions are systematically investigated on the diffusion behaviors of ethylene in solid and molten LDPE.
Recognizing genetic disease: A key aspect of pediatric pulmonary care
Authors: Yonker Lael M. , Hawley Megan H. , Moschovis Peter P. , Lu Mengdi , Kinane T. Bernard
Published: June 2020

Advancement in technology has improved recognition of genetic etiologies of disease, which has impacted diagnosis and management of rare disease patients in the pediatric pulmonary clinic. This review provides an overview of genetic conditions that are likely to present with pulmonary features and require extensive care by the pediatric pulmonologist. Increased familiarity with these conditions allows for improved care of these patients by reducing time to diagnosis, tailoring management, and prompting further investigation into these disorders.
The future is here: Integrating genetics into the pediatric pulmonary clinic
Authors: Hawley Megan H. , Moschovis Peter P. , Lu Mengdi , Kinane T. Bernard , Yonker Lael M.
Published: June 2020

Recognition of underlying genetic etiologies of disease is increasing at an exponential rate, likely due to greater access to and lower cost of genetic testing. Monogenic causes of disease, or conditions resulting from a mutation or mutations in a single gene, are now well recognized in every subspecialty, including pediatric pulmonary medicine; thus, it is important to consider genetic conditions when evaluating children with respiratory disease. In the pediatric pulmonary clinic, genetic testing should be considered when multiple family members present with similar or related clinical features and when individuals have unusual clinical presentations, such as early‐onset disease or complex, syndromic features. This review provides a practical guide for genetic diagnosis in the pediatric pulmonary setting, including a review of genetic concepts, considerations for test selection and results in interpretation, as well as an overview of genetic differential diagnoses for common pediatric pulmonary phenotypes. Genetic conditions that commonly present to the pediatric pulmonary clinic are reviewed in a companion article by Yonker et al.
Overview of the ChILD Research Network: A roadmap for progress and success in defining rare diseases
Authors: Casey Alicia M. , Deterding Robin R. , Young Lisa R. , Fishman Martha P. , Fiorino Elizabeth K. , Liptzin Deborah R.
Published: June 2020

Children's interstitial and diffuse lung diseases are a diverse group of rare lung disorders that present in childhood with diffuse pulmonary infiltrates and respiratory signs and symptoms. Children with these disorders face high morbidity and mortality and their families must cope with overwhelming uncertainty. Physicians caring for these patients are challenged by a paucity of directed therapies, or even understanding of natural history. Through the establishment of the Children's Interstitial Lung Disease Foundation Research Network and the Children's Interstitial Lung Disease Foundation significant progress has been made through collaboration and research. This review outlines the past and current successes in the new and rapidly growing field of Children's Interstitial and Diffuse Lung Disease.
Mechanical and Optical Properties of Stretchable Silicon Nanocrystal/Polydimethylsiloxane Nanocomposites
Authors: Izadi Alborz , Toback Branton , Sinha Mayank , Millar Andrew , Bigelow Michael , Roccabianca Sara , Anthony Rebecca
Published: June 2020

Nanoparticle‐infused polymer composites have long been an area of interest due to the typically stabilizing effects they have on the mechanical behavior of the composites, as well as added functionalities such as reduced surface resistance. Newer applications of these nanocomposites include dispersing optoelectronically functional nanoparticles in polymer matrices, for example, including luminescent nanocrystals in rigid slabs for luminescent solar concentrating photovoltaics and electrochromic panels. Dispersion of luminescent nanocrystals in stretchable polymers adds novel possibilities for applications, such as wearable health monitoring systems, flexible communications devices, and more. To leverage the exciting combined properties that these nanocomposites promise, there is a pressing need to evaluate and understand the interconnections between the optical effects, mechanical behavior, and the properties of the constituents. Herein, the optical and mechanical behavior of brightly emissive silicon nanocrystal/polydimethylsiloxane (PDMS) nanocomposites are investigated as a function of nanocrystal concentration and nanocrystal surface functionality. Mechanically, incorporating the nanocrystals at higher concentration leads to a dramatic reduction in the mechanical properties of the nanocomposite. The results suggest that the nanocrystal inclusions interfere with polymer cross‐linking, changing the mechanical behavior of the host PDMS as compared to the control.
Quantification of Sodium‐Ion Migration in Silicon Nitride by Flatband‐Potential Monitoring at Device‐Operating Temperatures
Authors: von Gastrow Guillaume , Martinez-Loran Erick , Scharf Jonathan , Clenney Jacob , Meier Rico , Bandaru Prabhakar , Bertoni Mariana I. , Fenning David P.
Published: June 2020

A trap‐corrected bias–temperature–stress (TraC‐BTS) method to quantify the kinetics of ion migration in dielectrics based on capacitance–voltage measurements is presented. The method is based on the extraction of flatband potential (Vfb) shifts in metal–insulator–semiconductor test structures an enables the reliability assessment of semiconductor dielectrics and solar cells. Herein, it is shown that carrier trapping in the dielectric must be accounted for, as it strongly affects the measurement of flatband potential in silicon‐nitride‐based capacitors. This effect is corrected by isolating the contribution of trapping on Vfb using contamination‐free control devices. A specific drift‐diffusion model of the ion kinetics presented herein allows the extraction of ion diffusivity. An Arrhenius relationship is obtained for sodium diffusivity in silicon nitride in a temperature range from 30 °C to 90 °C at an electric field of 1 MV cm−1, yielding a prefactor and an activation energy , with a 95% confidence interval of [] eV for the diffusivity. These quantitative kinetics confirm that silicon nitride may be a poor sodium migration barrier under a significant electric field.
Origin of p‐Type Conduction in Amorphous CuI: A First‐Principles Investigation
Authors: Lee Miso , Youn Yong , Jeong Jae Kyeong , Kang Youngho , Han Seungwu
Published: June 2020

Recently, Jun et al. (Adv. Mater. 2018, 30, 1706573) reported Sn‐doped amorphous phases of CuI (a‐CuI) as a new class of transparent p‐type semiconductors. It is surprising that high mobilities are found despite amorphous structures tend to localize carriers, particularly the directional p orbitals of anions. To reveal the microscopic origin of the new p‐type amorphous semiconductors, density functional theory calculations are performed, and structural and electrical properties of a‐CuI are investigated. Amorphous models from melt‐quench simulations consist of structural motifs that resemble local orders in crystalline polymorphs of CuI. Despite the absence of translational symmetry, states at valence band maximum (VBM) are substantially extended in linear ways due to the hybridization between I‐5p states, explaining the high hole mobilities in the experiment. Sn‐doped a‐CuI is also investigated and it is found that Sn atoms stabilize the amorphous structure without disturbing the hole transport. Furthermore, results on nonstoichiometric models show that Cu‐deficiency increases the hole concentration in a‐CuI and also enhances the delocalization of VBM states, which is consistent with the experimental observation that the hole mobility increases with doping concentrations. Herein, the origin of hole conduction in amorphous CuI is enlightened, which is believed to contribute in the development of high‐performance p‐type amorphous materials.
Dual‐Wavelength Focusing through Fresnel Zone Plate Fabricated in Lithium Niobate Crystal by Femtosecond Laser Micromachining
Authors: Zhu Bing , Liu Xiangmin , Liu Haigang , Liu Yi'an , Yan Xiongshuo , Chen Yuping , Chen Xianfeng
Published: June 2020

Herein, a simple method is proposed that realizes the dual‐wavelength focusing of second‐harmonic (SH) and fundamental frequency (FF) through amplitude‐type nonlinear Fresnel zone plate (FZP). The FZP is fabricated by femtosecond laser micromachining with 0 or +1 binary modulation of quadratic susceptibility in lithium niobate crystal. The evolution of the SH beam focusing intensity patterns with 2 cm focal length at 532 nm wavelength is theoretically and experimentally studied. Based on the birefringence phase matching, the measured normalized conversion efficiency for peak power of 1.9 × 10−5% W−1 cm−2 is achieved in the SH focal spot. The amplitude‐type nonlinear FZP realizes the focusing of the FF beam and SH beam simultaneously, which opens wide possibilities in the integration of laser beam shaping, nonlinear frequency conversion, and laser focusing for ultra‐compact on‐chip device requirement.
Direct Evidence of Catalytic Role of Boron in Graphite‐to‐Diamond Solid‐Phase Conversion under High Pressure
Authors: Bagramov Rustem , Filonenko Vladimir , Zibrov Igor , Lyapin Sergey , Vlasov Igor
Published: June 2020

Herein experimental evidence on the catalytic role of boron in the conversion of graphite to diamond is presented. Highly ordered graphite with up to 1.5% of carbon atoms substituted with boron is obtained from a mixture of nanoglobular carbon and amorphous boron at 5.0 GPa and 1400–1700 °C. It transforms completely into heavily boron‐doped diamond at a pressure of 7.5–8.0 GPa and temperature of 1600–1650 °C, which is well below the melting temperature of boron–carbon eutectic.
Intramolecular proton transfer in the isomerization of hydroxyacetone: Characterization based on reaction force analysis and the bond fragility spectrum
Authors: Joseph Huiet V. , Derricotte Wallace D.
Published: June 2020

The mechanism of isomerization of hydroxyacetone to 2‐hydroxypropanal is studied within the framework of reaction force analysis at the M06‐2X/6‐311++G(d,p) level of theory. Three unique pathways are considered: (a) a step‐wise mechanism that proceeds through the formation of the Z‐isomer of their shared enediol intermediate, (b) a step‐wise mechanism that forms the E‐isomer of the enediol, and (c) a concerted pathway that bypasses the enediol intermediate. Energy calculations show that the concerted pathway has the lowest activation energy barrier at 45.7 kcal mol−1. The reaction force, chemical potential, and reaction electronic flux are calculated for each reaction to characterize electronic changes throughout the mechanism. The reaction force constant is calculated in order to investigate the synchronous/asynchronous nature of the concerted intramolecular proton transfers involved. Additional characterization of synchronicity is provided by calculating the bond fragility spectrum for each mechanism.
On the discrepancy of random low degree set systems
Authors: Bansal Nikhil , Meka Raghu
Published: June 2020

Motivated by the celebrated Beck‐Fiala conjecture, we consider the random setting where there are n elements and m sets and each element lies in t randomly chosen sets. In this setting, Ezra and Lovett showed an discrepancy bound when n ≤ m and an O(1) bound when n ≫ mt. In this paper, we give a tight bound for the entire range of n and m, under a mild assumption that . The result is based on two steps. First, applying the partial coloring method to the case when and using the properties of the random set system we show that the overall discrepancy incurred is at most . Second, we reduce the general case to that of using LP duality and a careful counting argument.
Heavy Alkali Treatment of Post‐Sulfurized Cu(In,Ga)Se2 Layers: Effect on Absorber Properties and Solar Cell Performance
Authors: Keller Jan , Bilousov Oleksandr V. , Neerken Janet , Wallin Erik , Martin Natalia M. , Riekehr Lars , Edoff Marika , Platzer-Björkman Charlotte
Published: June 2020

This contribution evaluates a sequential post‐deposition treatment of Cu(In,Ga)Se2 (CIGS) films, consisting of 1) a post‐sulfurization in elemental S‐atmosphere and 2) a subsequent treatment by heavy alkali fluorides (Alk‐PDT). First, the effect of the sulfurization step on the corresponding solar cell performance is investigated and optimum process parameters, leading to an efficiency improvement, are identified. Losses in carrier collection observed after S‐incorporation are attributed to an increased grain boundary (GB) recombination. It is found that the corresponding reduction in short‐circuit current density can be mitigated by a RbF‐ or KF‐PDT, supposedly by depleting GBs in Cu. However, in strong contrast to non‐sulfurized CIGS, the Alk‐PDT results in a lower open‐circuit voltage and distortions in the current–voltage (I–V) characteristics for sulfurized absorbers. Possible explanations are the absence of a wide‐gap surface phase and/or air exposure between the post‐treatment steps. It is further proposed that a back contact barrier may be responsible for the distortions in I–V.
Deep learning from a statistical perspective
Authors: Yuan Yubai , Deng Yujia , Zhang Yanqing , Qu Annie
Published: June 2020

As one of the most rapidly developing artificial intelligence techniques, deep learning has been applied in various machine learning tasks and has received great attention in data science and statistics. Regardless of the complex model structure, deep neural networks can be viewed as a nonlinear and nonparametric generalization of existing statistical models. In this review, we introduce several popular deep learning models including convolutional neural networks, generative adversarial networks, recurrent neural networks, and autoencoders, with their applications in image data, sequential data and recommender systems. We review the architecture of each model and highlight their connections and differences compared with conventional statistical models. In particular, we provide a brief survey of the recent works on the unique overparameterization phenomenon, which explains the strengths and advantages of using an extremely large number of parameters in deep learning. In addition, we provide a practical guidance on optimization algorithms, hyperparameter tuning, and computing resources.
Physicochemical, Morphological, and Molecular Properties of Starch Isolated from Dioscorea and Oxalis Tubers from Hidalgo State, Mexico
Authors: Hernández‐Uribe Juan Pablo , Meza‐Nieto Martín , Palma‐Rodríguez Heidi Maria , Navarro‐Cortez Ricardo Omar , Guzmán‐Ortiz Fabiola Araceli , Bello‐Pérez Luis Arturo , Vargas‐Torres Apolonio
Published: June 2020

Starches are isolated from tubers of Dioscorea and Oxalis tuberosa (OT) grown in Hidalgo and surrounding areas. The starch particle sizes of Dioscorea bulbifera (DB) show a bimodal distribution, whereas those of Dioscorea mexicana Schidw (DM) and OT show unimodal distributions. The Dioscorea starch granules have a round shape, while those of OT have an elongated shape. Significant differences (p < 0.05) in pasting properties among the starches are observed, with DB showing the lowest viscosity value and DM showing the highest viscosity value. The peak and pasting temperatures show similar patterns, with higher values observed in the Dioscorea starches than in the OT starch. The gelatinization temperature values are low in the DB starch, compared to the DM and OT starches, which is consistent with the small granule size in DB. The interval in amylose content in the starches is 25.9% to 32.3%, classifying as normal starches. Molecular analysis reveals differences in molar mass and gyration radius between the amylopectin and amylose fractions of the starches, parameters that influence the physicochemical, pasting, and enzymatic hydrolysis characteristics of starches. The characterization of the tuber starches in this study reveals the potential of these under‐used food crops.
Homogenization of parabolic problems with dynamical boundary conditions of reactive‐diffusive type in perforated media
Authors: Anguiano María
Published: June 2020

This paper deals with the homogenization of the reaction‐diffusion equations in a domain containing periodically distributed holes of size ε, with a dynamical boundary condition ofreactive‐diffusivetype, i.e., we consider the following nonlinear boundary condition on the surface of the holeswhere denotes the Laplace–Beltrami operator on the surface of the holes, ν is the outward normal to the boundary, plays the role of a surface diffusion coefficient andgis the nonlinear term. We generalize our previous results established in the case of a dynamical boundary condition ofpure‐reactivetype, i.e., with . We prove the convergence of the homogenization process to a nonlinear reaction‐diffusion equation whose diffusion matrix takes into account the reactive‐diffusive condition on the surface of the holes.
Gauge theory and boundary integrability. Part II. Elliptic and trigonometric cases
Authors: Bittleston Roland , Skinner David
Published: June 2020

Abstract

We consider the mixed topological-holomorphic Chern-Simons theory introduced by Costello, Yamazaki & Witten on a ℤ2 orbifold. We use this to construct semi- classical solutions of the boundary Yang-Baxter equation in the elliptic and trigonometric cases. A novel feature of the trigonometric case is that the ℤ2 action lifts to the gauge bundle in a z-dependent way. We construct several examples of K -matrices, and check that they agree with cases appearing in the literature.
Discrete symmetries, weak coupling conjecture and scale separation in AdS vacua
Authors: Buratti Ginevra , Calderón José , Mininno Alessandro , Uranga Angel M.
Published: June 2020

Abstract

We argue that in theories of quantum gravity with discrete gauge symmetries, e.g. Z

k
, the gauge couplings of U(1) gauge symmetries become weak in the limit of large k, as g → k

−α
with α a positive order 1 coefficient. The conjecture is based on black hole arguments combined with the Weak Gravity Conjecture (or the BPS bound in the supersymmetric setup), and the species bound. We provide explicit examples based on type IIB on AdS5
×
S
5
/
Z

k
orbifolds, and M-theory on AdS4
×
S
7
/
Z

k
ABJM orbifolds (and their type IIA reductions). We study AdS4 vacua of type IIA on CY orientifold compactifications, and show that the parametric scale separation in certain infinite families is controlled by a discrete Z

k
symmetry for domain walls. We accordingly propose a refined version of the strong AdS Distance Conjecture, including a parametric dependence on the order of the discrete symmetry for 3-forms.
Gravitational production of scalar dark matter
Authors: Cembranos Jose A.R. , Garay Luis J. , Sánchez Velázquez Jose M.
Published: June 2020

Abstract

We investigate the gravitational production of scalar dark matter particles during the inflationary and reheating epochs. The oscillatory behavior of the curvature scalar R during the reheating phase generates two different enhancement mechanisms in the particle production. On the one hand, as it has been already discussed in previous works, it induces tachyonic instabilities in the field which are the dominant enhancement mechanism for light masses. On the other hand, we have found that it also provokes a resonant effect in the ultraviolet region of the spectrum which becomes dominant for masses in the range 109 GeV to 1013 GeV. We have developed an analytical approximation to describe this resonance effect and its consequences on the ultraviolet regime. Once we have calculated the theoretical gravitational production, we constrain the possible values of the phenomenological field parameters to be considered as a dark matter candidate. We do so by comparing the theoretically predicted abundance with the observed one and ensuring that the theoretical prediction does not lead to overproduction. In particular, we find that there is a region of intermediate masses that is forbidden as they would lead to overproduction.
Islands in Schwarzschild black holes
Authors: Hashimoto Koji , Iizuka Norihiro , Matsuo Yoshinori
Published: June 2020

Abstract

We study the Page curve for asymptotically flat eternal Schwarzschild black holes in four and higher spacetime dimensions. Before the Page time, the entanglement entropy grows linearly in time. After the Page time, the entanglement entropy of a given region outside the black hole is largely modified by the emergence of an island, which extends to the outer vicinity of the event horizon. As a result, it remains a constant value which reproduces the Bekenstein-Hawking entropy, consistent with the finiteness of the von Neumann entropy for an eternal black hole.
Soft fragmentation on the celestial sphere
Authors: Neill Duff , Ringer Felix
Published: June 2020

Abstract

We develop two approaches to the problem of soft fragmentation of hadrons in a gauge theory for high energy processes. The first approach directly adapts the standard resummation of the parton distribution function’s anomalous dimension (that of twist-two local operators) in the forward scattering regime, using k

T
-factorization and BFKL theory, to the case of the fragmentation function by exploiting the mapping between the dynamics of eikonal lines on transverse-plane to the celestial-sphere. Critically, to correctly resum the anomalous dimension of the fragmentation function under this mapping, one must pay careful attention to the role of regularization, despite the manifest collinear or infra- red finiteness of the BFKL equation. The anomalous dependence on energy in the celestial case, arising due to the mismatch of dimensionality between positions and angles, drives the differences between the space-like and time-like anomalous dimension of parton densities, even in a conformal theory. The second approach adapts an angular-ordered evolution equation, but working in 4 − 2ϵ dimensions at all angles. The two approaches are united by demanding that the anomalous dimension in 4 − 2ϵ dimensions for the parton distribution function determines the kernel for the angular-ordered evolution to all orders.
Anatomical Versus Nonanatomical Resection for Colorectal Liver Metastasis
Authors: She Wong Hoi , Cheung Tan To , Ma Ka Wing , Tsang Simon H. Y. , Dai Wing Chiu , Chan Albert C. Y. , Lo Chung Mau
Published: June 2020

Background

Anatomical resection (AR) for colorectal liver metastasis (CLM) is disputable. We investigated the impact of AR on short‐term outcomes and survival in CLM patients.

Methods

Patients having hepatectomy with AR or nonanatomical resection (NAR) for CLM were reviewed. Comparison was made between AR and NAR groups. Group comparison was performed again after propensity score matching with ratio 1:1.

Results

AR group (n = 234 vs n = 89 in NAR group) had higher carcinoembryonic antigen level (20 vs 7.8 ng/mL, p ≤ 0.001), more blood loss (0.65 vs 0.2 L, p < 0.001), more transfusions (19.2% vs 3.4%, p = 0.001), longer operation (339.5 vs 180 min, p < 0.001), longer hospital stay (9 vs 6 days, p < 0.001), more tumors (p < 0.001), larger tumors (4 vs 2 cm, p < 0.001), more bilobar involvement (20.9% vs 7.9%, p = 0.006), and comparable survival (overall, p = 0.721; disease‐free, p = 0.695). After propensity score matching, each group had 70 patients, with matched tumor number, tumor size, liver function, and tumor marker. AR group had more open resections (85.7% vs 68.6%, p = 0.016), more blood loss (0.556 vs 0.3 L, p = 0.001), more transfusions (17.1% vs 4.3%, p = 0.015), longer operation (310 vs 180 min, p < 0.001), longer hospital stay (8.5 vs 6 days, p = 0.002), comparable overall survival (p = 0.819), and comparable disease‐free survival (p = 0.855).

Conclusion

Similar disease‐free survival and overall survival of CLM patients were seen with the use of AR and NAR. However, AR may entail a more eventful postoperative course. NAR with margin should be considered whenever feasible.
Experimental evaluation of cylinder vortex shedding noise reduction using porous material
Authors: Geyer Thomas F.
Published: June 2020

The tonal noise generation of a circular cylinder in a uniform flow is an important source of aerodynamic noise. It can be found at parts of the landing gear of airplanes, at pantographs of trains, at antennas and basically all other protruding parts of vehicles. This noise is due to the periodic shedding of vortices along the cylinder span. One method to reduce this noise is the use of flow permeable covers around the cylinders. In the present study, measurements were performed in an aeroacoustic wind tunnel on a large set of porous covered cylinders. In addition to varying the porous material, which is characterized by its air flow resistivity and its porosity, the thickness of the porous layer was varied as well. The measurements were performed at Reynolds numbers between 14,000 and 103,000 using microphones located in the acoustic far field. It was found that the porous covers lead to a notable narrowing of the vortex shedding tonal peak in the sound pressure level spectra, an effect that increases with increasing porosity and thickness and decreasing air flow resistivity of the porous layer. Based on the large set of experimental data, basic trends were derived for the estimation of the vortex shedding Strouhal number and the reduction in the energy in the vortex shedding peak using the method of linear regression. Constant temperature anemometry measurements in the wake of selected cylinders basically showed a similar narrowing of the vortex shedding peak in the spectra of the turbulent velocity fluctuations. In addition, the measurement of wake profiles showed a reduction in the mean velocity and the turbulence in the wake as well as a widening of the wake region, while an analysis of the spanwise coherence revealed that the cause of the overall noise reduction is not a breakup of spanwise turbulent structures. Rather, the results imply that viscous damping of turbulent flow pressure amplitudes by the porous material strongly contributes to the noise reduction.

Graphic abstract
Enlarged perivascular spaces in multiple sclerosis on magnetic resonance imaging: a systematic review and meta-analysis
Authors: Granberg Tobias , Moridi Thomas , Brand Judith S. , Neumann Susanne , Hlavica Martin , Piehl Fredrik , Ineichen Benjamin V.
Published: June 2020

Background

Perivascular spaces can become detectable on magnetic resonance imaging (MRI) upon enlargement, referred to as enlarged perivascular spaces (EPVS) or Virchow-Robin spaces. EPVS have been linked to small vessel disease. Some studies have also indicated an association of EPVS to neuroinflammation and/or neurodegeneration. However, there is conflicting evidence with regards to their potential as a clinically relevant imaging biomarker in multiple sclerosis (MS).

Methods

To perform a systematic review and meta-analysis of EPVS as visualized by MRI in MS. Nine out of 299 original studies addressing EPVS in humans using MRI were eligible for the systematic review and meta-analysis including a total of 457 MS patients and 352 control subjects.

Results

In MS, EPVS have been associated with cognitive decline, contrast-enhancing MRI lesions, and brain atrophy. Yet, these associations were not consistent between studies. The meta-analysis revealed that MS patients have greater EPVS prevalence (odds ratio = 4.61, 95% CI = [1.84; 11.60], p = 0.001) as well as higher EPVS counts (standardized mean difference [SMD] = 0.46, 95% CI = [0.26; 0.67], p < 0.001) and larger volumes (SMD = 0.88, 95% CI = [0.19; 1.56], p = 0.01) compared to controls.

Conclusions

Available literature suggests a higher EPVS burden in MS patients compared to controls. The association of EPVS to neuroinflammatory or -degenerative pathology in MS remains inconsistent. Thus, there is currently insufficient evidence supporting EPVS as diagnostic and/or prognostic marker in MS. In order to benefit future comparisons of studies, we propose recommendations on EPVS assessment standardization in MS. PROSPERO No: CRD42019133946.
Low-risk trials for children and pregnant women threatened by unnecessary strict regulations. Does the coming EU Clinical Trial Regulation offer a solution?
Authors: Knaapen Max , Ploem Martine Corrette , Kruijt Maya , Oudijk Martijn A. , van der Graaf Rieke , Bet Pierre M. , Bakx Roel , van Heurn L. W. Ernst , Gorter Ramon R. , van der Lee Johanna H.
Published: June 2020

Investigator-initiated clinical trials are crucial for improving quality of care for children and pregnant women as they are often excluded from industry-initiated trials. However, trials have become increasingly time-consuming and costly since the EU Clinical Trial Directive entered into force in 2001. This directive made compliance with ICH-Good Clinical Practice Guidelines (ethical and quality standard for conducting human subject research) mandatory for all clinical trials, regardless of its risk-classification. By discussing two investigator-initiated, ‘low-risk’ drug trials, we aim to illustrate that compliance with all GCP requirements makes trials very laborious and expensive, while a clear rationale is missing. This discourages clinical researchers to start and carry out investigator-initiated research. However, the forthcoming EU Clinical Trial Regulation (No 536/2014) seems to provide a solution as it allows for less stringent rules for low-risk trials. We want to raise awareness for these developments in both the clinical research community and the European and national regulatory authorities. Implementation of this forthcoming Regulation regulatory policies should be done in such a way that investigator-initiated trials evaluating standard care interventions will become more feasible. This will allow us to obtain evidence on optimal and safe treatments, especially for groups that are underrepresented in medical research.

What is Known• Investigator-initiated trials are indispensable for improving care for children and pregnant women as they are often excluded from industry-initiated trials• Trials have become increasingly time-consuming and costly because of mandatory compliance with ICH-GCP guidelines

What is New• The forthcoming EU Clinical Trial Regulation allows less stringent rules for low-risk trials• The national legislator and regulatory authorities should recognize the importance of this opportunity and implement the Regulation in such a way that investigator-initiated trials will become more feasible