bluuebunny/crossref_metadata_2025 huggingface dataset:
Large deflection and post-buckling of thin-walled structures by finite elements with node-dependent kinematics
Authors:   Mul Group, Carrera E. , Pagani A. , Augello R.
Published: November 2020

In the framework of finite elements (FEs) applications, this paper proposes the use of the node-dependent kinematics (NDK) concept to the large deflection and post-buckling analysis of thin-walled metallic one-dimensional (1D) structures. Thin-walled structures could easily exhibit local phenomena which would require refinement of the kinematics in parts of them. This fact is particularly true whenever these thin structures undergo large deflection and post-buckling. FEs with kinematics uniform in each node could prove inappropriate or computationally expensive to solve these locally dependent deformations. The concept of NDK allows kinematics to be independent in each element node; therefore, the theory of structures changes continuously over the structural domain. NDK has been successfully applied to solve linear problems by the authors in previous works. It is herein extended to analyze in a computationally efficient manner nonlinear problems of beam-like structures. The unified 1D FE model in the framework of the Carrera Unified Formulation (CUF) is referred to. CUF allows introducing, at the node level, any theory/kinematics for the evaluation of the cross-sectional deformations of the thin-walled beam. A total Lagrangian formulation along with full Green–Lagrange strains and 2nd Piola Kirchhoff stresses are used. The resulting geometrical nonlinear equations are solved with the Newton–Raphson linearization and the arc-length type constraint. Thin-walled metallic structures are analyzed, with symmetric and asymmetric C-sections, subjected to transverse and compression loadings. Results show how FE models with NDK behave as well as their convenience with respect to the classical FE analysis with the same kinematics for the whole nodes. In particular, zones which undergo remarkable deformations demand high-order theories of structures, whereas a lower-order theory can be employed if no local phenomena occur: this is easily accomplished by NDK analysis. Remarkable advantages are shown in the analysis of thin-walled structures with transverse stiffeners.
Accounting for adaptation and its effectiveness in International Environmental Agreements
Authors: Furini Francesco , Bosello Francesco
Published: November 2020

This paper analyses, within a standard International Environmental Agreement game, the effect of the introduction of adaptation on climate negotiation. The model expands the existing literature by considering a double relation between the two strategies. The common assumption that higher mitigation decreases the marginal benefit of adaptation and vice versa is enriched allowing for the possibility that mitigation, leading to lower and more manageable damages, determines a greater effectiveness of adaptive measures. We find the possibility for adaptation and mitigation to be strategic complements and not, as commonly believed, substitutes. Yet, as already known from the literature, the presence of adaptation can determine upward-sloping mitigation reaction functions regardless of the strategic relationship between mitigation and adaptation. When this is the case, the grand coalition can form. Nonetheless, large participation can induce substantive welfare gains only if adaptation and mitigation are strategic complements.
The extracellular lactate-to-pyruvate ratio modulates the sensitivity to oxidative stress-induced apoptosis via the cytosolic NADH/NAD+ redox state
Authors: Go Simei , Kramer Thorquil T. , Verhoeven Arthur J. , Oude Elferink Ronald P. J. , Chang Jung-Chin
Published: November 2020

The advantages of the Warburg effect on tumor growth and progression are well recognized. However, the relevance of the Warburg effect for the inherent resistance to apoptosis of cancer cells has received much less attention. Here, we show here that the Warburg effect modulates the extracellular lactate-to-pyruvate ratio, which profoundly regulates the sensitivity towards apoptosis induced by oxidative stress in several cell lines. To induce oxidative stress, we used the rapid apoptosis inducer Raptinal. We observed that medium conditioned by HepG2 cells has a high lactate-to-pyruvate ratio and confers resistance to Raptinal-induced apoptosis. In addition, imposing a high extracellular lactate-to-pyruvate ratio in media reduces the cytosolic NADH/NAD+ redox state and protects against Raptinal-induced apoptosis. Conversely, a low extracellular lactate-to-pyruvate ratio oxidizes the cytosolic NADH/NAD+ redox state and sensitizes HepG2 cells to oxidative stress-induced apoptosis. Mechanistically, a high extracellular lactate-to-pyruvate ratio decreases the activation of JNK and Bax under oxidative stress, thereby inhibiting the intrinsic apoptotic pathway. Our observations demonstrate that the Warburg effect of cancer cells generates an anti-apoptotic extracellular environment by elevating the extracellular lactate-to-pyruvate ratio which desensitizes cancer cells towards apoptotic insults. Consequently, our study suggests that the Warburg effect can be targeted to reverse the lactate-to-pyruvate ratios in the tumor microenvironment and thereby re-sensitize cancer cells to oxidative stress-inducing therapies.
DiaBLa: a corpus of bilingual spontaneous written dialogues for machine translation
Authors: Bawden Rachel , Bilinski Eric , Lavergne Thomas , Rosset Sophie
Published: November 2020

We present a new English–French dataset for the evaluation of Machine Translation (MT) for informal, written bilingual dialogue. The test set contains 144 spontaneous dialogues (5700+ sentences) between native English and French speakers, mediated by one of two neural MT systems in a range of role-play settings. The dialogues are accompanied by fine-grained sentence-level judgments of MT quality, produced by the dialogue participants themselves, as well as by manually normalised versions and reference translations produceda posteriori. The motivation for the corpus is twofold: to provide (i) a unique resource for evaluating MT models, and (ii) a corpus for the analysis of MT-mediated communication. We provide an initial analysis of the corpus to confirm that the participants’ judgments reveal perceptible differences in MT quality between the two MT systems used.
Conditional variance penalties and domain shift robustness
Authors: Heinze-Deml Christina , Meinshausen Nicolai
Published: November 2020

When training a deep neural network for image classification, one can broadly distinguish between two types of latent features of images that will drive the classification. We can divide latent features into (i) ‘core’ or ‘conditionally invariant’ features$$C$$Cwhose distribution$$C\vert Y$$C|Y, conditional on the classY, does not change substantially across domains and (ii) ‘style’ features$$S$$Swhose distribution$$S\vert Y$$S|Ycan change substantially across domains. Examples for style features include position, rotation, image quality or brightness but also more complex ones like hair color, image quality or posture for images of persons. Our goal is to minimize a loss that is robust under changes in the distribution of these style features. In contrast to previous work, we assume that the domain itself is not observed and hence a latent variable. We do assume that we can sometimes observe a typically discrete identifier or “$$\mathrm {ID}$$IDvariable”. In some applications we know, for example, that two images show the same person, and$$\mathrm {ID}$$IDthen refers to the identity of the person. The proposed method requires only a small fraction of images to have$$\mathrm {ID}$$IDinformation. We group observations if they share the same class and identifier$$(Y,\mathrm {ID})=(y,\mathrm {id})$$(Y,ID)=(y,id)and penalize the conditional variance of the prediction or the loss if we condition on$$(Y,\mathrm {ID})$$(Y,ID). Using a causal framework, this conditional variance regularization (CoRe) is shown to protect asymptotically against shifts in the distribution of the style variables in a partially linear structural equation model. Empirically, we show that the CoRepenalty improves predictive accuracy substantially in settings where domain changes occur in terms of image quality, brightness and color while we also look at more complex changes such as changes in movement and posture.
Application of Soft Data in Nodule Resource Estimation
Authors: Ellefmo Steinar Løve , Kuhn Thomas
Published: November 2020

Minerals and metals are of uttermost importance in our society, and mineral resources on and beneath the deep ocean floor represent a huge potential. Deciding whether mining from the deep ocean floor is financially, environmentally and technologically feasible requires information. Due to great depths and harsh conditions, this information is expensive and time and resource consuming to obtain. It is therefore important to use every piece of data in an optimum way. In this study, data retrieved from images and expert knowledge were used to estimate minimum and maximum nodule abundances at image locations from an area in the Clarion-Clipperton-Zone of the equatorial North East Pacific. From the minimum and maximum values, box cores and the spatial correlation quantified through variogram, a conditional expectation and associated uncertainty were obtained through the Gibbs sampler. The conditional expectation and the uncertainty were used with the assumed certain abundance data from the box cores in a kriging exercise to obtain better informed estimates of the block by block abundance. The quality assessment of the estimations was done based on distance criterion and on kriging quality indicators like the slope of regression and the weight of the mean. From the original image locations, alternative image configurations were tested, and it was shown that such alternatives produce better estimates, without extra costs. Future improvements will focus on improving the estimation of the minimum and the maximum values at image locations.
Stress Corrosion Testing of CMSX-4, CM247LC DS and IN6203DS Ni-Base Superalloys
Authors: Chapman Neil , Gray Simon , Sumner Joy , Nicholls John
Published: November 2020

The combination of stress and hot corrosion may result in Ni-base superalloys experiencing stress corrosion cracking, of which, the mechanisms are little understood. The aim of this research was to enhance the understanding by performing a series of stress corrosion exposures, at temperatures of 550, 500 and 450 °C, on: CMSX-4, CM247LC DS and IN6203DS superalloys. After completing the exposures, the superalloys were ranked with respect to the severity of the cracking experienced (CMSX-4 showing the worst severity, followed by CM247LC DS and then IN6203DS which showed no evidence of cracking at all) and the ranking appeared to be correlated to the gamma prime volume fraction. This suggests the gamma prime volume fraction is associated with the crack mechanism with lower values increasing the resistance to stress corrosion cracking. From the findings of this research, a new crack initiation/propagation mechanism is proposed which is based on a summation of stresses that includes those associated with the gamma prime.
In-Silico Screening of Lipid-Based Drug Delivery Systems
Authors: Brinkmann Joscha , Exner Lara , Luebbert Christian , Sadowski Gabriele
Published: November 2020

Purpose

This work proposes an in-silico screening method for identifying promising formulation candidates in complex lipid-based drug delivery systems (LBDDS).

Method

The approach is based on a minimum amount of experimental data for API solubilites in single excipients. Intermolecular interactions between APIs and excipients as well as between different excipients were accounted for by the Perturbed-Chain Statistical Associating Fluid Theory. The approach was applied to the in-silico screening of lipid-based formulations for ten model APIs (fenofibrate, ibuprofen, praziquantel, carbamazepine, cinnarizine, felodipine, naproxen, indomethacin, griseofulvin and glibenclamide) in mixtures of up to three out of nine excipients (tricaprylin, Capmul MCM, caprylic acid, Capryol™ 90, Lauroglycol™ FCC, Kolliphor TPGS, polyethylene glycol, carbitol and ethanol).

Results

For eight out of the ten investigated model APIs, the solubilities in the final formulations could be enhanced by up to 100 times compared to the solubility in pure tricaprylin. Fenofibrate, ibuprofen, praziquantel, carbamazepine are recommended as type I formulations, whereas cinnarizine and felodipine showed a distinctive solubility gain in type II formulations. Increased solubility was found for naproxen and indomethacin in type IIIb and type IV formulations. The solubility of griseofulvin and glibenclamide could be slightly enhanced in type IIIb formulations. The experimental validation agreed very well with the screening results.

Conclusion

The API solubility individually depends on the choice of excipients. The proposed in-silico-screening approach allows formulators to quickly determine most-appropriate types of lipid-based formulations for a given API with low experimental effort.

Graphical abstract
On the aromaticity of uracil and its 5-halogeno derivatives as revealed by theoretically derived geometric and magnetic indexes
Authors: Rzepiela Kacper , Buczek Aneta , Kupka Teobald , Broda Małgorzata A.
Published: November 2020

The problem of aromaticity in heterocyclic rings of uracil and its 5-halogenoderivatives (5XU) was analyzed theoretically by calculating modified harmonic oscillator model of aromaticity (HOMA) for Heterocycle Electron Delocalization (HOMHED), nucleus-independent chemical shift parameters (NICS) and the so-called scan experiments, using helium-3 atom as a magnetic probe. The impact of halogen electronegativity on C5 atom’s NBO charges was also investigated. Water, as a polar environment, has a negligible impact on 5XU aromaticity. The most stable diketo tautomer shows a very low aromaticity while the “rare” dihydroxy form (tautomer No 6) is aromatic and resembles benzene. This is in agreement with traditional drawing of chemical formula of uracil’s six-membered ring, directly showing three alternating single and double bonds in its tautomer No 6. No good correlation between magnetic and geometric indexes of aromaticity for the studied 5XU tautomers was found. Linear correlation between the magnitude of NICS minimum, as well as the distance of the minimum above uracil ring plane center from 3He NMR chemical shift scan plot with respect to halogen electronegativity were observed. A strong linear dependence of magnetic index of aromaticity and the electronegativity of 5X substituent was observed.
Optimization research on the site selection of fire safety for mega projects sites based on multi-objective particle swarm
Authors: Xiang Yong , Cao Wuwen , Zheng Huidan , Su Yangyang
Published: November 2020

There are large fire safety hidden dangers in the construction site of mega-projects. In order to improve the ability of fire safety emergency response on site, in this paper, the number of demand points on the construction site are firstly determined, and through using risk assessment of operating conditions method, the risk is evaluated and the risk level is determined. Secondly, according to the construction site layout criteria and fire safety technical criteria, and taking the economy, distance, time and coverage of fire safety site selection as the basic factors, a multi-objective site selection optimization model for fire safety points is established. Multi-objective particle swarm optimization is used to solve the multi-objective site selection model, and a series of fire safety point site selection schemes are obtained. Finally, the analytic hierarchy process is used to select the best scheme from a series of schemes. The research ideas and conclusions of this paper provide a scientific and reasonable analysis framework and ideas for site selection of fire safety points for mega projects, which has certain applicability and practicability.
Road-cut Slope Stability Assessment along Himalayan National Highway NH-154A, India
Authors: Singh Kanwarpreet , Kumar Virender
Published: November 2020

The Himalayan range, being a complex terrain, is highly prone to slope instability in many parts because of the natural conditions and human interference. In the present study, road cut slope stability assessment has been carried out along Chamba-Bharmour Section (Chamba District, Himachal Pradesh) along Chakki (Pathankot, Punjab) - Bharmour (Chamba, Himachal Pradesh). The cut slopes with the potential of failures have been identified taking into consideration the geological and geotechnical complexities in the selected zone. Rock mass characterization methodologies have been used for the assessment of slope instability . The varying stability classes of the rock slopes have been calculated using rock mass rating (RMR) and modified slope mass rating (SMR) methods. The kinematic analysis approach has been utilized for the identification of different failure modes in heavily jointed, fractured and structurally controlled rock masses. Fourteen potentially unstable slopes were selected to assess their criticality by RMR and modified SMR approaches and their stability classes were identified.
Removal of multiple pesticide residues from water by low-pressure thin-film composite membrane
Authors: Mukherjee Ayan , Mehta Romil , Saha Soumen , Bhattacharya A. , Biswas Pabitra Kumar , Kole Ramen Kumar
Published: November 2020

The study evaluated removal efficiency of 43 pesticides from water by thin-film composite polyamide membrane indigenously prepared by interfacial polymerization of 1,3-phenylenediamine and 1,3,5 trimesoyl chloride coated on asymmetric polysulfone support. Membrane performance was evaluated by gas and liquid chromatography mass spectroscopy determination of multiple pesticides remaining in feed and permeated water following the application of pesticides each @ 0.02, 0.05, and 0.10 mg/L in de-ionized water. The membrane was most efficient in the rejection of persistent organochlorine insecticides, viz. endosulfans (100%), dichlorodiphenyltrichloroethane (95%), and hexachlorocyclohexane (92%). Out of 43 selected pesticides, 33 were removed by > 80%. Size exclusion mass transfer played a significant role for molecules to pass through the membrane as observed for endosulfan isomers, endosulfan sulphate, and difenoconazole with molecular weight > 400. Pesticide rejection was also related to hydrophobicity (Log P). Hydrophobic pesticides with log P > 4.5 were rejected by > 80%, while monocrotophos with less hydrophobicity (log P = − 0.22) exhibited poor rejection (38%). Water flux decreased with an increase in pesticide concentration. The process of pesticide filtration was optimized at 200 psi. The results indicated the potential of the membrane to remove pesticides from water.
Perceived effects of farm tractors in four African countries, highlighted by participatory impact diagrams
Authors: Daum Thomas , Adegbola Ygué Patrice , Kamau Geoffrey , Kergna Alpha Oumar , Daudu Christogonus , Zossou Roch Cedrique , Crinot Géraud Fabrice , Houssou Paul , Mose Lawrence , Ndirpaya Yarama , Wahab A. A. , Kirui Oliver , Oluwole Fatunbi Abiodun
Published: November 2020

Agricultural mechanization is on the rise in Africa. A widespread replacement of manual labor and animal traction will change the face of African agriculture. Despite this potentially transformative role, only a few studies have looked at the effects of mechanization empirically, mostly focusing on yields and labor alone. This is the first paper that explores perceived agronomic, environmental, and socioeconomic effects together, thereby revealing linkages and trade-offs, some of which have been hitherto unknown. Data were collected using a novel data collection method called “participatory impact diagrams” in four countries: Benin, Kenya, Nigeria, and Mali. In 129 gendered focus group discussions, 1330 respondents from 87 villages shared their perceptions on the positive and negative effects of agricultural mechanization, and developed causal impact chains. The results suggest that mechanization is likely to have more far-reaching agronomic, environmental, and socioeconomic consequences than commonly assumed. Most perceived effects were positive, suggesting that mechanization can help to reduce poverty and enhance food security but other effects were negative such as deforestation, soil erosion, land-use conflicts, and gender inequalities. Accompanying research and policy efforts, which reflect variations in local agro-ecological and socioeconomic conditions, are needed to ensure that mechanization contributes to an African agricultural transformation that is sustainable from a social, economic, and environmental perspective.
Evaluation of Terpenes’ Degradation Rates by Rumen Fluid of Adapted and Non-adapted Animals
Authors: Poulopoulou I. , Hadjigeorgiou I.
Published: November 2020

The aim of the present study was to evaluate terpenes degradation rate in the rumen fluid from adapted and non-adapted animals. Four castrated healthy animals, two rams and two bucks, were used. Animals were daily orally dosed for 2 weeks with 1 g of each of the following terpenes, α-pinene, limonene and β-caryophyllene. At the end of each week, rumen fluid (RF) samples were assayed in vitro for their potential to degrade terpenes over time. For each animal, a 10 mL reaction medium (RM) at a ratio 1:9 (v/v) was prepared and a terpenes solution at a concentration of 100 μg/ml each, was added in each RM tube. Tubes were incubated at 39 °C under anaerobic conditions and their contents sampled at 0, 2, 4, 8, 21 and 24 h. RF could degrade terpenes as it was shown by the significantly (P < 0.05) higher overall degradation rates. Individual terpene degradation rates, were significantly (P < 0.05) higher in week 5 for limonene and marginally (P = 0.083) higher also in week 5 for α-pinene. In conclusion, the findings of the present preliminary study suggest that terpenes can be degraded in the rumen fluid.
Influence of different Ni coatings on the long-term behavior of ultrasonic welded EN AW 1370 cable/EN CW 004A arrestor dissimilar joints
Authors: Köhler Tobias , Grätzel Michael , Bergmann Jean Pierre
Published: November 2020

The increasing demand for energy-efficient vehicles requires suitable methods for cost and weight reduction. This can be achieved by the replacement of copper by aluminum, in particular for the on-board power systems. However, the complete substitution is restricted by the mechanical and physical material properties of aluminum as well as challenges in the aluminum copper interface. The challenges concern the corrosion vulnerability and the occurrence of brittle intermetallic compounds (IMC) which can negatively influence the mechanical properties and the electrical conductivity. Therefore, current investigations focus on the one hand on the realization of dissimilar aluminum copper joints by suitable joining technologies, like ultrasonic welding, and on the other hand on the assurance of a sufficient prevention against harmful corrosion effects. In cases where the joint cannot be protected against corrosion by sealing, nickel coatings can be used to protect the joint. In the present study, the influence of electroless, electroplated, and sulfamate nickel coatings was investigated regarding the long-term stability. The joints were performed as industry-related arrester connections, consisting of EN AW 1370 cables and EN CW 004A terminals. The samples were exposed to corrosive as well as electrical, thermal, and mechanical stress tests according to current standards and regulations.
Assessing psychopathology in bariatric surgery candidates: discriminant validity of the SCL-90-R and SCL-K-9 in a large sample of patients
Authors: Bianciardi Emanuela , Gentileschi Paolo , Niolu Cinzia , Innamorati Marco , Fabbricatore Mariantonietta , Contini Lorenzo Maria , Procenesi Leonardo , Siracusano Alberto , Imperatori Claudio
Published: November 2020

Purpose

Pre-surgical psychosocial evaluation of bariatric surgery (BS) patients should identify psychiatric issues that could worsen after surgery and those requiring additional ongoing intervention. In this view, the use of reliable, appropriate and concise evaluating instruments is of critical importance. The aim of the present study was to investigate the clinical utility of both the Symptom Checklist 90-Revised (SCL-90-R) and its brief unidimensional version, the so-called Symptom-Checklist-K-9 (SCL-K-9) in detecting the presence of psychiatric disorders among bariatric surgery (BS) candidates.

Methods

Seven-hundred-and-ninety-eight BS candidates (563 women and 235 men; mean age: 44.15 ± 11.45) were enrolled in the present study. All participants underwent a full psychiatric interview and were administered the SCL-90-R.

Results

Three-hundred-and-sixty-two patients (45.4%) met the criteria for a diagnosis of at least one psychiatric disorder and ninety-nine patients (12.4%) had psychiatric comorbidities. In the current sample, 219 patients (27.4%) met the criteria for binge eating disorders (BED), 158 (19.8%) met the criteria for major depressive disorder (MDD), and 67 (8.4%) met both criteria. A receiver operating characteristic (ROC) curves procedure showed that both the SCL-90-R and the SCL-K-9 satisfactorily categorize patients with any psychiatric disorder, both BED and MDD (area under the ROC curve ≥ 0.70, p < 0.001).

Conclusion

Our results suggest that the SCL-90-R and the SCL-K-9 may represent first-level screening tests identifying at-risk patients, eligible for a more expensive or time-consuming clinical assessment.

Level of evidence

Level V, cross-sectional, descriptive study.
Effect of temperature and mating pair on tribological properties of DLC and GLC coatings under high pressure lubricated by MoDTC and ZDDP
Authors: Liu Kang , Kang Jia-jie , Zhang Guang-an , Lu Zhi-bin , Yue Wen
Published: November 2020

Diamond-like carbon (DLC) and graphite-like carbon (GLC) coatings have good prospects for improving the surface properties of engine parts. However, further understanding is needed on the effect of working conditions on tribological behaviors. In this study, GLC and two types of DLC coatings were deposited on GCr15 substrate for investigation. The friction and wear properties of self-mated and steel-mated pairs were evaluated. Two temperatures (25 and 90 °C), three lubrication conditions (base oil, molybdenum dithiocarbamate (MoDTC)-containing oil, MoDTC+zinc dialkyldithiophosphate (ZDDP)-containing oil), and high Hertz contact stress (2.41 GPa) were applied in the experiments. The results showed that high temperature promoted the effect of ZDDP on steel-mated pairs, but increased wear under base oil lubrication. The increased wear for steel-mated pairs lubricated by MoDTC-containing oil was due to abrasive wear probably caused by MoO3 and β-FeMoO4. It was also found that in most cases, the tribological properties of self-mated pairs were better than those of steel-mated pairs.
Synergistic nano-tribological interaction between zinc dialkyldithiophosphate (ZDDP) and methyl oleate for biodiesel-fueled engines
Authors: Hamdan Siti Hartini , Lee Chiew Tin , Lee Mei Bao , Chong William Woei Fong , Chong Cheng Tung , Sanip Suhaila Mohd
Published: November 2020

In biodiesel-fueled compression-ignition (CI) engines, dilution by unburned biodiesel has been found to have adverse effects on the boundary lubrication properties of additives in fully formulated engine lubricants. Such dilution of engine lubricants could be even more pronounced for CI engines running on higher blend concentrations of biodiesel. Given the nanoscopic nature of the interaction, this study seeks to determine the nano-tribological properties of an engine lubricant additive (e.g., zinc dialkyldithiophosphate (ZDDP)) when diluted with a fatty acid methyl ester (e.g., methyl oleate). Using lateral force microscopy (LFM) together with a fluid imaging technique, the lowest nanoscopic friction forces and coefficient of friction values (0.068–0.085) were measured for ZDDP when diluted with 70 vol% of methyl oleate. These values are also observed to be lower than those measured for neat ZDDP and neat methyl oleate, respectively, under similar conditions. Subsequently, interpreting the data with the Eyring thermal activation energy approach, it could then be elucidated that the lower frictional losses observed for the contact lubricated with this volumetric mixture are a result of the lower potential energy barrier and activation energy required to initiate sliding. These energy values are approximated to be 2.6% and 28.9% (respectively) lower than that of the contact lubricated with neat ZDDP. It was also found that the mixture, at this volumetric concentration, possesses the highest possible pressure activation energy (load-carrying capacity) along with the lowest possible shear activation energy (shearing), potentially indicating optimum tribological conditions for boundary lubrication. Thus, the findings of this study suggest that an optimum concentration threshold exists in which a synergistic nano-tribological interaction between additives and fatty acid methyl esters can be attained, potentially reducing boundary frictional losses of lubricated conjunctions. Such findings could prove to be essential in effectively formulating synergistic additive concentrations for engine lubricants used in biodiesel-fueled CI engines.
Running-in behavior of a H-DLC/Al2O3 pair at the nanoscale
Authors: Shi Pengfei , Sun Junhui , Liu Yunhai , Zhang Bin , Zhang Junyan , Chen Lei , Qian Linmao
Published: November 2020

Diamond-like carbon (DLC) film has been developed as an extremely effective lubricant to reduce energy dissipation; however, most films should undergo running-in to achieve a super-low friction state. In this study, the running-in behaviors of an H-DLC/Al2O3 pair were investigated through a controllable single-asperity contact study using an atomic force microscope. This study presents direct evidence that illustrates the role of transfer layer formation and oxide layer removal in the friction reduction during running-in. After 200 sliding cycles, a thin transfer layer was formed on the Al2O3 tip. Compared with a clean tip, this modified tip showed a significantly lower adhesion force and friction force on the original H-DLC film, which confirmed the contribution of the transfer layer formation in the friction reduction during running-in. It was also found that the friction coefficient of the H-DLC/Al2O3 pair decreased linearly as the oxygen concentration of the H-DLC substrate surface decreased. This phenomenon can be explained by a change in the contact surface from an oxygen termination with strong hydrogen bond interactions to a hydrogen termination with weak van der Waals interactions. These results provide new insights that quantitatively reveal the running-in mechanism at the nanoscale, which may help with the design optimization of DLC films for different environmental applications.
Leukocytospermia in late adolescents: possible clinical interpretations
Authors: La Vignera S. , Cannarella R. , Aversa A. , Rago R. , Condorelli R. A. , Calogero A. E.
Published: November 2020

Background

No data are currently available on the implication of amicrobial leukocytospermia in male adolescents. Therefore, the primary aim of this study was to evaluate the prevalence of amicrobial leukocytospermia among non-smoker late adolescents who were exposed to other risky lifestyles for the andrological health. The main andrological clinical features of adolescents with leukocytospermia were also reported.

Methods

This is a cross-sectional study carried out in 80 boys. Each adolescent underwent a physical examination, and to the assessment of sperm conventional parameters, seminal leukocytes concentration and immature germ cell evaluation. A possible correlation between seminal leukocytes and immature germ cells and testicular volume (TV) was tested.

Results

The adolescents enrolled in this study had 18.0 ± 0.4 (range 18.1–18.9) years. Unprotected sexual intercourse was referred by 38% of them. Sexual dysfunctions were found in 25% and isolated hypoactive sexual desire in 12.5% of boys. Low TV and penile length in flaccidity were found in 44% and 30% of them, respectively. Only 41% had normozoospermia at the sperm analysis, whereas 19% had isolated oligozoospermia, 15% oligo-asthenozoospermia, and 25% oligo-astheno-teratozoospermia. Leukocytospermia occurred in 25% (20 out of 80) of adolescents. No seminal infection was detected in 19% (15 out of 80) of them. Adolescents with leukocytospermia had lower progressive sperm motility, percentage of normal forms, TV, and a higher percentage of immature germ cells compared to those without leukocytospermia. Semen leukocyte concentration correlated negatively with TV and positively with the percentage of immature germ cells in the ejaculate.

Conclusion

Leukocytospermia, increased immature germ cell number, and low TV identify a distinct phenotype suggestive of testicular tubulopathy. Primary prevention of male infertility and the counselling for andrological risky lifestyles is mandatory and should be started as early as possible.
Clinical exome sequencing is a powerful tool in the diagnostic flow of monogenic kidney diseases: an Italian experience
Authors: Vaisitti Tiziana , Sorbini Monica , Callegari Martina , Kalantari Silvia , Bracciamà Valeria , Arruga Francesca , Vanzino Silvia Bruna , Rendine Sabina , Togliatto Gabriele , Giachino Daniela , Pelle Alessandra , Cocchi Enrico , Benvenuta Chiara , Baldovino Simone , Rollino Cristiana , Fenoglio Roberta , Sciascia Savino , Tamagnone Michela , Vitale Corrado , Calabrese Giovanni , Biancone Luigi , Bussolino Stefania , Savoldi Silvana , Borzumati Maurizio , Cantaluppi Vincenzo , Chiappero Fabio , Ungari Silvana , Peruzzi Licia , Roccatello Dario , Amoroso Antonio , Deaglio Silvia
Published: November 2020

Background

A considerable minority of patients on waiting lists for kidney transplantation either have no diagnosis (and fall into the subset of undiagnosed cases) because kidney biopsy was not performed or histological findings were non-specific, or do not fall into any well-defined clinical category. Some of these patients might be affected by a previously unrecognised monogenic disease.

Methods

Through a multidisciplinary cooperative effort, we built an analytical pipeline to identify patients with chronic kidney disease (CKD) with a clinical suspicion of a monogenic condition or without a well-defined diagnosis. Following the stringent phenotypical and clinical characterization required by the flowchart, candidates meeting these criteria were further investigated by clinical exome sequencing followed by in silico analysis of 225 kidney-disease-related genes.

Results

By using an ad hoc web-based platform, we enrolled 160 patients from 13 different Nephrology and Genetics Units located across the Piedmont region over 15 months. A preliminary “remote” evaluation based on well-defined inclusion criteria allowed us to define eligibility for NGS analysis. Among the 138 recruited patients, 52 (37.7%) were children and 86 (62.3%) were adults. Up to 48% of them had a positive family history for kidney disease. Overall, applying this workflow led to the identification of genetic variants potentially explaining the phenotype in 78 (56.5%) cases.

Conclusions

These results underline the importance of clinical exome sequencing as a versatile and highly useful, non-invasive tool for genetic diagnosis of kidney diseases. Identifying patients who can benefit from targeted therapies, and improving the management of organ transplantation are further expected applications.
ExoHCR: a sensitive assay to profile PD-L1 level on tumor exosomes for immunotherapeutic prognosis
Authors: Hu Lujun , Chen Wenjie , Zhou Shurong , Zhu Guizhi
Published: November 2020

Cancer immunotherapy has made recent breakthrough, including immune checkpoint blockade (ICB) that inhibits immunosuppressive checkpoints such as programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1). However, most cancer patients do not durably respond to ICB. To predict ICB responses for patient stratification, conventional immunostaining has been used to analyze the PD-L1 expression level on biopsied tumor tissues but has limitations of invasiveness and tumor heterogeneity. Recently, PD-L1 levels on tumor cell exosomes showed the potential to predict ICB response. Here, we developed a non-invasive, sensitive, and fast assay, termed as exosome-hybridization chain reaction (ExoHCR), to analyze tumor cell exosomal PD-L1 levels. First, using αCD63-conjugated magnetic beads, we isolated exosomes from B16F10 melanoma and CT26 colorectal cancer cells that were immunostimulated to generate PD-L1-positive exosomes. Exosomes were then incubated with a conjugate of PD-L1 antibody with an HCR trigger DNA (T), in which one αPD-L1-T conjugate carried multiple copies of T. Next, a pair of metastable fluorophore-labeled hairpin DNA (H1 and H2) were added, allowing T on αPD-L1-T to initiate HCR in situ on bead-conjugated exosome surfaces. By flow cytometric analysis of the resulting beads, relative to αPD-L1-fluorophore conjugates, ExoHCR amplified the fluorescence signal intensities for exosome detection by 3–7 times in B16F10 cells and CT26 cells. Moreover, we validated the biostability of ExoHCR in culture medium supplemented with 50% FBS. These results suggest the potential of ExoHCR for non-invasive, sensitive, and fast PD-L1 exosomal profiling in patient stratification of cancer immunotherapy.
Divide and Invest: Bargaining in a Dynamic Framework
Authors: Flamini Francesca
Published: November 2020

Many negotiations (for instance, among political parties or partners in a business) are characterized by dynamic bargaining: current agreements affect future bargaining possibilities. We study such situations using bargaining games á la Rubinstein (Econometrica 50:97–109, 1982), with the novelty that players can decide how much to invest, as well as how to share the residual surplus for their own consumption. Their investment decisions affect the size of the next surplus. In line with the existing literature, we focus on Markov Perfect Equilibria, where consumption and investment are linear time-invariant functions of capital and show that standard results in bargaining theory can be overturned. For instance, a more patient proposer may consume less than his opponent. The intuition is that when capital is productive, both parties have incentives to invest, however, the most patient party wishes to invest significantly more than his opponent. Then, to prioritize investment—which affects future bargaining possibilities—the former must make larger concessions and let the latter consume more. Another interesting result is that if a player becomes more patient, both parties may reduce their investment. The key underlying driver of this result is that when counteroffers become cheaper for an impatient party, he is able to reduce his investment and consume more. This forces his opponent to make larger concessions (and reduce his investment plan). Moreover, extreme demands (where a player consumes all the residual surplus) are possible in equilibrium, under fairly modest assumptions. Finally, only when bargaining is frictionless, is the equilibrium efficient.
Prevalence and special clinical and biochemical characteristics of familial type 1 (insulin dependent) diabetes mellitus in pediatric patients in a tertiary care setting
Authors: AlMutair Angham , AlSabty Norah , AlNuaim Hala , Al Hamdan Rawan , Moukaddem Afaf
Published: November 2020

Background and Objectives:

The hereditable nature of type 1 diabetes mellitus (T1DM) makes it a condition that is in some cases shared among siblings. Studies that focus on the epidemiology of T1DM among siblings are scarce. The primary focus of the study is to estimate the prevalence of familial T1DM among siblings and the secondary focus is to identify the presence of any special clinical or biochemical characteristics specific to this entity.

Methods:

In a retrospective cross-sectional study, the charts of 308 children (>1 year) diagnosed with type 1 diabetes mellitus in a Saudi tertiary care setting were reviewed. The patients who have one sibling or more with T1DM were included. The prevalence of familial T1DM among siblings was calculated, and specific clinical and biochemical characteristics were investigated. Data were analyzed using Statistical Package for the Social Sciences software version 22 (IBM SPSS Statistics for Windows). The control group includes all patients with type I DM who were excluded for sibling with DM.

Results:

The prevalence of familial T1DM among siblings was estimated at 15.9%. Seventy-four percent of the patients with a positive family history of diabetes mellitus had one affected sibling only. The clinical presentation showed no significant differences relative to the age of presentation, gender, parental consanguinity, diabetic ketoacidosis at presentation, and its number of episodes. For the biochemical characteristics, autoantibody tests revealed no statistically significant difference, but the mean initial HbA1c levels were lower in patients who had diabetic siblings.

Conclusion:

The prevalence of familial T1DM was found to be higher than that reported in other studies. No specific clinical or biochemical features were found to characterize familial T1DM among siblings.
Throughput interventions to reduce emergency department crowding: A systematic review
Authors: Grant Kiran L. , Bayley Conrad J. , Premji Zahra , Lang Eddy , Innes Grant
Published: November 2020

Objective

Emergency department (ED) throughput efficiency is largely dependent on staffing and process, and many operational interventions to increase throughput have been described.

Methods

We systematically searched Medline, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials to find studies describing the impact of throughput strategies on ED length of stay and left without being seen rates. Two independent reviewers screened studies, evaluated quality and risk of bias, and stratified eligible studies by intervention type. We assessed statistical heterogeneity using the chi-squared statistic and the I-squared (I2) statistic, and pooled results where appropriate. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed.

Results

Ninety-four (94) studies met inclusion criteria (Cohen's k = 0.7). Most were observational, five were determined to be low quality (Cohen's k = 0.6), and almost all reported modest reductions in length of stay and left without being seen rates, although there was substantial variability within and between intervention types. Fast track and patient streaming interventions showed the most consistent reduction in length of stay and left without being seenrates. Shifting high-level providers to triage appears effective and generally cost neutral. Evidence for enhanced testing strategies and alternative staffing models was less compelling.

Conclusions

Introducing a fast track and optimizing processes for important case-mix groups will likely enhance throughput efficiency. Expediting diagnostic and treatment decisions by shifting physician-patient contact to the earliest possible process point (e.g., triage) is an effective cost-neutral strategy to increase flow. Focusing ED staff on operational improvement is likely to improve performance, regardless of the intervention type.
Tales from New York City, the pandemic epicenter: A case study of COVID-19 impact on clinical and translational research training at the Icahn School of Medicine at Mount Sinai
Authors: Fattah Layla , Peter Inga , Sigel Keith , Gabrilove Janice L.
Published: November 2020

In the spring of 2020, New York City was at the epicenter of the COVID-19 pandemic in the USA, resulting in disruption of TL1 and KL2-mentored Clinical and Translational Science (CTS) research at the Icahn School of Medicine at Mount Sinai (ISMMS). The impact of the pandemic on trainees’ research productivity and career plans was explored using a qualitative survey. Participant responses were analyzed using coding and categorization. Six key themes emerged: redirection of effort, reduced access to people, lack of access to resources, home as a workplace, future uncertainty, and stress and anxiety. Insight into participant experiences allows for the development of support strategies and resources to address trainee needs.
On Λ-Fleming–Viot processes with general frequency-dependent selection
Authors: Gonzalez Casanova Adrian , Smadi Charline
Published: November 2020

We construct a multitype constant-size population model allowing for general selective interactions as well as extreme reproductive events. Our multidimensional model aims for the generality of adaptive dynamics and the tractability of population genetics. It generalises the idea of Krone and Neuhauser [39] and González Casanova and Spanò [29], who represented the selection by allowing individuals to sample several potential parents in the previous generation before choosing the ‘strongest’ one, by allowing individuals to use any rule to choose their parent. The type of the newborn can even not be one of the types of the potential parents, which allows modelling mutations. Via a large population limit, we obtain a generalisation of$\Lambda$-Fleming–Viot processes, with a diffusion term and a general frequency-dependent selection, which allows for non-transitive interactions between the different types present in the population. We provide some properties of these processes related to extinction and fixation events, and give conditions for them to be realised as unique strong solutions of multidimensional stochastic differential equations with jumps. Finally, we illustrate the generality of our model with applications to some classical biological interactions. This framework provides a natural bridge between two of the most prominent modelling frameworks of biological evolution: population genetics and eco-evolutionary models.
Rate of convergence for traditional Pólya urns
Authors: Janson Svante
Published: November 2020

Consider a Pólya urn with balls of several colours, where balls are drawn sequentially and each drawn ball is immediately replaced together with a fixed number of balls of the same colour. It is well known that the proportions of balls of the different colours converge in distribution to a Dirichlet distribution. We show that the rate of convergence is $\Theta(1/n)$ in the minimal $L_p$ metric for any $p\in[1,\infty]$, extending a result by Goldstein and Reinert; we further show the same rate for the Lévy distance, while the rate for the Kolmogorov distance depends on the parameters, i.e. on the initial composition of the urn. The method used here differs from the one used by Goldstein and Reinert, and uses direct calculations based on the known exact distributions.
Non-Comparability with respect to the convex transform order with applications
Authors: Arab Idir , Hadjikyriakou Milto , Oliveira Paulo Eduardo
Published: November 2020

In the literature of stochastic orders, one rarely finds results characterizing non-comparability of random variables. We prove simple tools implying the non-comparability with respect to the convex transform order. The criteria are used, among other applications, to provide a negative answer for a conjecture about comparability in a much broader scope than its initial statement.
On a new stochastic model for cascading failures
Authors: Lee Hyunju
Published: November 2020

In this paper, to model cascading failures, a new stochastic failure model is proposed. In a system subject to cascading failures, after each failure of the component, the remaining component suffers from increased load or stress. This results in shortened residual lifetimes of the remaining components. In this paper, to model this effect, the concept of the usual stochastic order is employed along with the accelerated life test model, and a new general class of stochastic failure models is generated.