bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical study on the kinetics and thermodynamics of H‐atom abstractions from tetramethylsilane‐related species
Authors: Zhu Shan , Zhou Chong‐Wen
Published: December 2021

Theoretical kinetics and thermochemistry investigations on the H‐atom abstraction reactions by H and O atoms and OH and HO2 radicals from Si−C−O‐containing species such as Si(CH3)4, Si(CH3)3(OH), Si(CH3)2(OH)2, and Si(CH3)(OH)3 have been carried out in this work. The geometry, vibrational frequencies, and hindrance potential for each species are calculated at the B3LYP/6‐31G(2df,p) level of theory with the single‐point energies calculated at the G4 level of theory. The composite methods G3 and G4 are utilized to derive enthalpies of formation at 0 K by the atomization reaction methodology. ΔHf(298 K), S(298 K), and Cp(T) are calculated by using the statistical thermodynamics method. Conventional transition state theory is used over a wide temperature range (298.15−2000 K) for H‐atom abstraction reactions by H, O, and HO2 radicals from the species mentioned above, and variational transition state theory is used for H‐atom abstraction reactions by the OH radical. The kinetic and thermodynamic parameters based on high‐level theoretical calculations are compared with the literature data. Reactivity comparison between the similar hydrocarbons and silicon‐organic compounds for H‐atom abstractions is explored. A large difference exists between these two different systems when H‐atom abstractions are on hydroxyl sites.
Commercially available unoccupied aerial systems for monitoring harmful algal blooms: A comparative study
Authors: Fernandez‐Figueroa Edna G. , Wilson Alan E. , Rogers Stephanie R.
Published: December 2021

Reliable remote sensing platforms and methods for monitoring phytoplankton are needed for mitigating the detrimental impacts of cyanobacterial harmful algal blooms on small inland waterbodies. Commercial unoccupied aerial systems (UASs) present an affordable high‐resolution solution for the rapid assessment of cyanobacterial abundance in small aquatic systems by recording the reflectance of photosynthetic pigments found in all phytoplankton (i.e., chlorophyll a [Chl a]) and those related to cyanobacteria (i.e., phycocyanin). This study evaluates the performance of four sensors, including visible light spectra (red, green, blue ‐ [RGB]) sensors on the Phantom 4 and Phantom 4 Professional platforms, the MAPIR Survey3W modified multispectral (i.e., near‐infrared, green, blue) sensor, and the Parrott Sequoia multispectral (i.e., green, red, near‐infrared, red‐edge) sensor for estimating cyanobacterial abundance. The performance of each sensor was determined by comparing 26 vegetation indices to Chl a and phycocyanin measurements of 54 ponds that varied in size and productivity. Vegetation indices that included the red and near‐infrared wavelengths generated from Parrot Sequoia aerial images provided the best Chl a (i.e., Normalized Difference Vegetation Index, r2 = 0.79, p < 0.0001) and phycocyanin (i.e., Green Normalized Difference Vegetation Index, r2 = 0.64, p < 0.0001) estimates. The RGB sensors were moderately effective for estimating Chl a, whereas the MAPIR Survey3W generated poor estimates of both pigments due to differences in recorded wavelengths. Results suggest commercial multiband multispectral UAS sensors provide a low‐cost, plug‐and‐play alternative for managers and researchers interested in integrating remote sensing tools for quantitatively estimating phytoplankton abundance in small inland systems.
High‐Sensitivity, Long‐Durability, and Wearable Pressure Sensor Based on the Polypyrrole/Reduced Graphene Oxide/(Fabric–Sponge–Fabric) for Human Motion Monitoring
Authors: Cheng Haonan , Xu Bo , Yang Kun , Yin Yun jie , Wang Chaoxia
Published: December 2021

Fabrics are among the best ideal materials for fabricating low‐cost flexible pressure sensors due to their outstanding air permeability, flexibility, and micro/nanorough structure. However, most of the fabric‐based pressure sensors suffer from poor stability, which severely limits their applications in the real life. In the previous work, the pressure sensor assembled from polyester fabric and polyurethane sponge in an integrated design shows good stability. Herein, a novel type of wearable pressure sensors with high sensitivity and long durability is prepared by the unique combination of a dense integrated material consisting of nylon fabric–latex sponge–nylon fabric (FSF), reduced graphene oxide (rGO), and in‐situ‐formed polypyrrole (PPy). Benefiting from the excellent electrical conductivity, compression performance, and piezoresistive property, the obtained PPy/rGO/FSF pressure sensor exhibits low operating voltage (1.0 V), high sensitivity (0.51 kPa−1), long durability (over 7500 cycles), as well as short response time (243 ms). As a result, the pressure sensor demonstrates high performance in monitoring human activities such as wrist pulses, exhalation/inhalation, head shaking, knee bending, and finger bending, indicating its great potential in human health monitoring and human–computer interaction.
Criteria for judging the immune markers of COVID‐19 disease vaccines
Authors: Lin Nan , Fu Haoxuan , Pu Dan , Quan Yuxin , Li Yueyi , Yin Xiaomeng , Wei Yuhao , Wang Hang , Ma Xuelei , Wei Xiawei
Published: December 2021

As severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) sweeping the world, effective and affordable vaccines are in urgent need. A reliable system for the assessment of SARS‐CoV‐2 vaccines would boost the development of vaccines and reduce the research cost. We constructed a logistic regression model and analyzed the relationship between antibody (Ab) level and efficacy of different vaccine types. The relationship between assessment dates and Ab levels was depicted by plotting the mean of Ab levels evolved over time and a fitted cubic polynomial model. Anti‐spike immunoglobulin G (IgG) could best estimate the vaccine efficacy (VE) (adjusted R2 = 0.731) and neutralizing Ab to live SARS‐CoV‐2 also explained a fine relationship (adjusted R2 = 0.577). Neutralizing Abs to live SARS‐CoV‐2 in inactivated virus vaccines reached a peak during days 40–60, and their receptor‐binding domain (RBD)‐IgG peaked during days 40–50. For messenger RNA (mRNA) and viral vector vaccines, their neutralizing Ab to live SARS‐CoV‐2 peaked later than day 40, and for RBD‐IgG during days 30–50. For mRNA and viral vector vaccines, their peak time of Abs was later than that in inactivated virus vaccines. RBD‐IgG peaked earlier than Ab to live SARS‐CoV‐2. Anti‐spike IgG and Ab to live SARS‐CoV‐2 may be good immune markers for VE assessment.
Regional innovation paths selection in complex environments of China: A configurational perspective
Authors: Han Guoyuan , Zhang Zhilin
Published: December 2021

This paper investigates conditional configurations for high innovation performance under complex regional environments in China from a configurational perspective. The results indicate that internal R&D is neither sufficient nor necessary for high innovation performance while it's an important component of those configurations for high innovation performance. Moreover, there are five configurations for high innovation performance and eight configurations for not‐high innovation performance emergent from complex nonlinear interactions among seven influencing factors of regional innovation. The structures of configurations for high innovation performance differ from those for not‐high innovation performance, revealing an asymmetric view of causality that underpins regional innovation performance.
Brainstem Biomarkers of Clinical Variant and Pathology in Progressive Supranuclear Palsy
Authors: Grijalva Rosalie M. , Pham Nha Trang Thu , Huang Qiao , Martin Peter R. , Ali Farwa , Clark Heather M. , Duffy Joseph R. , Utianski Rene L. , Botha Hugo , Machulda Mary M. , Weigand Stephen D. , Ahlskog J. Eric , Dickson Dennis W. , Josephs Keith A. , Whitwell Jennifer L.
Published: December 2021

Background

Magnetic resonance brainstem measurements are useful structural biomarkers in the Richardson's syndrome variant of progressive supranuclear palsy (PSP). However, it is unclear how these biomarkers differ across the phenotypic spectrum of PSP and how they relate to underlying pathology.

Objective

The aim of this study was to compare brainstem imaging measures across clinical variants of PSP and determine sensitivity and specificity based on pathologically diagnosed cases.

Methods

A total of 153 patients with PSP who represented eight clinical variants were recruited at Mayo Clinic (Rochester, MN, USA) and underwent structural magnetic resonance imaging (MRI). Midbrain and pons area and superior and middle cerebellar peduncle width measurements were performed, and midbrain/pons ratio and Magnetic Resonance Parkinsonism Index (MRPI) were calculated. Among the 43 patients who later died, PSP pathology was confirmed in 29, whereas 14 had other pathology.

Results

Brainstem measurements varied across PSP clinical variants and were most abnormal in PSP‐Richardson's syndrome and frontal variants, followed by PSP‐corticobasal, PSP‐speech/language, and PSP‐parkinsonism variants. All these variants showed abnormalities compared with controls. The PSP‐gait freezing variant and patients with prominent corticospinal tract signs showed normal brainstem measures. Among cases with confirmed PSP pathology, the midbrain area, midbrain/pons ratio, and MRPI were all more abnormal compared to those with other pathologies, with best differentiation obtained with the MRPI (sensitivity = 83%; specificity = 85%).

Conclusions

MRI brainstem measures show utility as diagnostic biomarkers across PSP clinical variants and have the potential to be useful in predicting underlying pathology. © 2021 International Parkinson and Movement Disorder Society
Dual nuclear magnetic resonance for probing intrinsic bone structure and a potential gut–bone axis in ovariectomized rats
Authors: He Weiwei , Jakobsen Louise M. A. , Zachariassen Line F. , Hansen Axel K. , Andersen Henrik J. , Bertram Hanne Christine
Published: December 2021

Currently, the existence of a gut–bone axis receives massive attention, and while sound premises and indirect proofs exist for the gut–bone axis concept, few studies have provided actual data linking the gut and bone physically. This study aimed to exploit the versatile nature of nuclear magnetic resonance (NMR) to link NMR relaxometry data on bone mineralization with NMR spectroscopic profiling of gut metabolites. For this purpose, sample material was obtained from a 6‐week intervention study with ovariectomized (OVX) rats (n = 49) fed with seven different diets varying in calcium content (0.2–6.0 mg/kg) and prebiotic fiber content (0–5.0% w/w). This design ensured a span in (i) calcium available for bone mineralization and (ii) metabolic activity in the gut. After termination of the intervention, longitudinal (T1), transverse (T2) relaxation, and mechanical bone strength were measured on the excised femur bones. A PLS model with high predictability (Q2 = 0.86, R2 = 0.997) was demonstrated between T2 decay curves and femur mechanical strength. Correlations were established between bone T2 populations and gut short‐chain fatty acids. In conclusion, the present dual NMR approach showed strong correlation between T2 relaxation and mechanical strength of the bone, and when metabolic activity in the gut was modulated by inulin, the potential existence of a gut–bone axis was demonstrated.
Repeatability and robustness of MP‐GRASP T1 mapping
Authors: Li Zhitao , Xu Xiang , Yang Yang , Feng Li
Published: December 2021

Purpose

To demonstrate the repeatability of fast 3D T1 mapping using Magnetization‐Prepared Golden‐angle RAdial Sparse Parallel (MP‐GRASP) MRI and its robustness to variation of imaging parameters including flip angle and spatial resolution in phantoms and the brain.

Theory and Methods

Multiple imaging experiments were performed to (1) assess the robustness of MP‐GRASP T1 mapping to B1 inhomogeneity using a single tube phantom filled with uniform MnCl2 liquid; (2) compare the repeatability of T1 mapping between MP‐GRASP and inversion recovery‐based spin‐echo (IR‐SE; over 12 scans), using a commercial T1MES phantom; (3) evaluate the longitudinal variation of T1 estimation using MP‐GRASP with varying imaging parameters, including spatial resolution, flip angle, TR/TE, and acceleration rate, using the T1MES phantom (106 scans performed over a period of 12 months); and (4) evaluate the variation of T1 estimation using MP‐GRASP with varying imaging parameters in the brain (24 scans in a single visit). In addition, the accuracy of MP‐GRASP T1 mapping was also validated against IR‐SE by performing linear correlation and calculating the Lin's concordance correlation coefficient (CCC).

Results

MP‐GRASP demonstrates good robustness to B1 inhomogeneity, with intra‐slice variability below 1% in the single tube phantom experiment. The longitudinal variability is good both in the phantom (below 2.5%) and in the brain (below 2%) with varying imaging parameters. The T1 values estimated from MP‐GRASP are accurate compared to that from the IR‐SE imaging (R2 = 0.997, Lin’s CCC = 0.996).

Conclusion

MP‐GRASP shows excellent repeatability of T1 estimation over time, and it is also robust to variation of different imaging parameters evaluated in this study.
Numerical and experimental study on dynamics of the planar mechanical system considering two revolute clearance joints
Authors: Bai Zhengfeng , Xu Fusong , Zhao Jijun
Published: December 2021

Due to assembly, wear and manufacturing errors and clearance in the joints are inevitable. When the clearance is introduced into a mechanical system, the impact force in the clearance joint will cause undesirable vibration of the system. In this paper, the dynamic responses of the mechanical system with two revolute clearance joints are studied using computational and experimental methodology. The clearance joint is considered as force constraint. The normal contact force and tangential friction force between the journal and bearing in a clearance joint are modeled using a nonlinear contact force model considering energy loss and a modified Coulomb friction model considering a dynamic friction coefficient, respectively. A planar slider‐crank mechanism with two revolute clearance joints is used to implement the study. The dynamic responses obtained from numerical simulation are compared with the experimental test. Numerical simulations and experimental tests for different clearance sizes and crank speeds are presented and discussed, respectively. The simulation results agree quite well with those of the experiment for different cases, which proves the accuracy and efficiency of the computational method for dynamics analysis of the mechanical system with two revolute clearance joints in this study. The investigation indicates that the clearances in revolute joints significantly affect the dynamic characteristics of mechanical systems, which must be considered in the precision analysis, design, and control of multibody systems, especially for high‐speed machinery.
One kind of transverse isotropic strength criterion and the transformation stress space
Authors: Wan Zheng , Liu Yuanyuan , Cao Wei , Wang Yujia , Xie Liyu , Fang Yufei
Published: December 2021

The geomaterials with original anisotropic properties formed in the natural process are usually simplified as a kind of cross‐anisotropic material. The spatial location of the depositional plane (DP) and the effective spatial mobilized plane (ESMP) in physical space is closely related to anisotropic properties; thus, the inclined angle between DP and ESMP is taken as a primary parameter governing the strength degree of geomaterial anisotropy. According to the concept of ESMP, the frictional capacity can be more effectively mobilized when the inclined angle between DP and ESMP is larger, inducing a higher stress strength. In this study, a new stress strength formula is proposed for geomaterials, which takes the cross‐anisotropic properties into account. The transformation strategy can be regarded as a strength criterion describing the convert of transversely isotropic behavior formula into an isotropic von Mises criterion formula. Based on the cross‐anisotropy strength criterion, the transformed stress (TS) equation can be derived by transforming the cross‐anisotropy stress space to the isotropic stress space. By using the proposed TS method, it is convenient to convert the traditional two‐dimensional (2D) constitutive models on the basis of the Von‐Mises criterion to the general three‐dimensional (3D) models considering cross‐anisotropy. Comparing the predicted and the tested results of strength and stress‐strain relationship tests for geomaterials under the true triaxial loading condition, the validity and the applicability of the proposed TS method with related criterion can be ensured.
Methylated tetra‐amide derivatives of paramagnetic complexes for magnetic resonance biosensing with both BIRDS and CEST
Authors: Zakaria Abul B. M. , Huang Yuegao , Coman Daniel , Mishra Sandeep K. , Mihailovic Jelena M. , Maritim Samuel , Rojas‐Quijano Federico A. , Jurek Paul , Kiefer Garry E. , Hyder Fahmeed
Published: December 2021

Paramagnetic agents that utilize two mechanisms to provide physiological information by magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) are described. MRI with chemical exchange saturation transfer (CEST) takes advantage of the agent's exchangeable protons (e.g., ‐OH or ‐NHx, where 2 ≥ x ≥ 1) to create pH contrast. The agent's incorporation of non‐exchangeable protons (e.g., ‐CHy, where 3 ≥ y ≥ 1) makes it possible to map tissue temperature and/or pH using an MRSI method called biosensor imaging of redundant deviation in shifts (BIRDS). Hybrid probes based upon 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetate chelate (DOTA4−) and its methylated analog (1,4,7,10‐tetraazacyclododecane‐α, α′, α″, α‴‐tetramethyl‐1,4,7,10‐tetraacetate, DOTMA4−) were synthesized, and modified to create new tetra‐amide chelates. Addition of several methyl groups per pendent arm of the symmetrical chelates, positioned proximally and distally to thulium ions (Tm3+), gave rise to favorable BIRDS properties (i.e., high signal‐to‐noise ratio (SNR) from non‐exchangeable methyl proton peaks) and CEST responsiveness (i.e., from amide exchangeable protons). Structures of the Tm3+ probes elucidate the influence of methyl group placement on sensor performance. An eight‐coordinate geometry with high symmetry was observed for the complexes: Tm‐L1 was based on DOTA4−, whereas Tm‐L2 and Tm‐L3 were based on DOTMA4−, where the latter contained an additional carboxylate at the distal end of each arm. The distance of Tm3+ from terminal methyl carbons is a key determinant for sustaining BIRDS temperature sensitivity without compromising CEST pH contrast; however, water solubility was influenced by introduction of hydrophobic methyl groups and hydrophilic carboxylate. Combined BIRDS and CEST detection of Tm‐L2, which features two high‐SNR methyl peaks and a strong amide CEST peak, should enable simultaneous temperature and pH measurements for high‐resolution molecular imaging in vivo.
A Newton‐type method for two‐dimensional eigenvalue problems
Authors: Lu Tianyi , Su Yangfeng
Published: December 2021

Two‐dimensional eigenvalue problems (2DEVP) equations in complex Hermitian case contain complex quadratic forms which is non‐holomorphic. In this case, standard Newton method fails to apply. An existing strategy to solve this problem is to transform them into real problems (TRN). However, this method doubles the size of equations and thus is time consuming. On the other hand, the non‐isolation of the solution set in 2DEVP also complicates the analysis. In this article, we propose a Newton type method which solves the problem caused by non‐holomophism and non‐isolation. It has locally quadratic convergence rate and is about at least twice as much efficient as TRN. We hope our ideas can provide insights for solving other problems including non‐holomorphism and non‐isolation. We apply our algorithm to calculate the distance to instability. Numerical experiments show its advantages in efficiency while keeping good convergence compared with the current state of art algorithms.
From multi‐physics models to neural network for predictive control synthesis
Authors: Blaud Pierre Clément , Chevrel Philippe , Claveau Fabien , Haurant Pierrick , Mouraud Anthony
Published: December 2021

The aim of this document is to present an efficient and systematic method of model‐based predictive control synthesis. Model predictive control requires using a model of a dynamical system, that can be linear, time‐varying, non‐linear, or identified from data. Finding a model that is both precise and simulatable at low computational cost can be challenging and time consuming due to requiring extensive knowledge of the system and physics as well as a large volume of data with relevant scenarios and sometimes a complicated identification work. (filtering noises and bias, data formatting, etc.) The proposed methodology begins with fine‐scale multi‐physics modeling, which is possible thanks to open model libraries (see Modelica). The obtained model is then simulated by considering ad hoc scenarios to generate data, which are then used to identify a neural network, that will support the predictive control syntheses. The systematic methodology is detailed and applied to the widely used control benchmark known as the quadruple tanks process. Results show that the methodology is accurately applied to optimize hyperparameters in finding a neural network model and to control the quadruple tanks process with the predictive controller.
Mathematically described model of poly(glycerol maleate) cross‐linking process using triethylenetetramine addition
Authors: Kolankowski Krzysztof , Gadomska‐Gajadhur Agnieszka , Wrzecionek Michał , Ruśkowski Paweł
Published: December 2021

Recently intensive development of tissue engineering has been noticeable. It has caused a considerable rise in scientists' interest in biomaterials, which build scaffolds. Beneficial are biocompatible and biodegradable polymers. Due to its structure, poly(glycerol maleate) (PGMal) can be such a material. The structure of this polymer has a reactive double bond group on which precious modification reactions can occur. This article aimed to optimize the process of cross‐linking PGMal using triethylenetetramine. The reaction was investigated without and with a solvent. Due to the high viscosity of the polymer, it was decided to carry out the optimisation in the solvent variant (in tetrahydrofuran). A central, compositional, two‐component plan was used to optimize the process. The optimizing value was the degree of conversion, calculated based on the proton nuclear resonance spectrum. Its maximization was sought. High‐conversion rates were obtained during the tests. The aza‐Michael addition turns out to be a priceless reaction to modify unsaturated polyesters. Selectivity is noticeable in solvent‐free variants. Complete substitution to maleic fragments and partial substitution to fumaric fragments was observed. No selectivity was observed in the presence of THF.
Durability of biopolymeric composites formulated with fillers from a by‐product of coffee roasting
Authors: Sisti Laura , Totaro Grazia , Rosato Antonella , Bozzi Cionci Nicole , Di Gioia Diana , Barbieri Luisa , Saccani Andrea
Published: December 2021

Particulate composites based on poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) biopolymers have been formulated. Silver skin (SSK), the by‐product derived from the roasting of coffee beans, has been milled to micrometric size and added up to a 30 wt% of loading, without any previous treatment. The dynamic mechanical properties of the composites have been investigated, as well as the stability toward UV and IR radiation. The filler improves some mechanical properties such as the elastic modulus (E′) mostly in PBS. Photoaging experiments demonstrate that SSK, due to its polyphenols content and antioxidant activity, is able to protect both PLA and PBS from UV degradation, highlighting an added value of SSK waste‐based composites.
Mechanically robust and self‐healing waterborne polyurethane nanocomposites based on inorganic organic hybrid materials and reversible covalent interaction
Authors: Wang Hui , Xu Junhuai , Wang Haoliang , Yang Shiwen , Wang Haibo
Published: December 2021

Endowing waterborne polyurethane (WPU) materials with mechanically reinforced and self‐healing property is a pressing issue for expanding practical applications. In this article, we proposed a simple method to give WPU with self‐healing properties while improving the mechanical properties. First, furfuryl‐modified silica nanoparticles (furan@SiO2) with high functionality and excellent dispersibility were prepared by the sol–gel method. Furan@SiO2 was then introduced into the side‐hanging maleimide WPU to form a thermally reversible inorganic–organic network (WMSPUS‐x) based on the Diels‐Alder reaction. The morphologies and properties of furan@SiO2 and WMSPUS‐x emulsions were analyzed by TEM and DLS, demonstrating the excellent dispersion of furan@SiO2 and the storage stability of emulsions. The cross‐linking density of the nanocomposites was varied by the furan@SiO2 contents, and the effects of cross‐linking density on mechanical and self‐healing properties were systematically investigated. In addition, the thermal stability of WMSPUS‐x nanocomposites was significantly improved shown by TGA results. Finally, qualitative and quantitative studies of the self‐healing process were carried out to verify that WMSPUS‐x nanocomposites possess great self‐healing capacity. The outcomes indicate that WMSPUS‐x nanocomposites have great potential for application as a smart material.
Asset/mechanical integrity: A PSM element that still bedevils
Authors: Hazzan Michael J. , Min Ken W.
Published: December 2021

Since the original version of this paper was published at the CCPS conference in 2006, the quality and health of asset integrity/mechanical integrity (AI/MI) programs in the process safety community have improved. However, it continues to be a difficult element to develop and implement. In many respects, it is still the “last frontier” of process safety and has been the last element to be fully addressed in the PSM community. This is not to say that inspection, testing, and preventive maintenance and other related activities that are part of AI/MI programs do not exist at facilities with process safety programs. Preventive and predictive maintenance programs have existed in the chemical/process industry for many years. What has been lacking in some cases are complete integrated AI/MI management system programs that address all of the subelements of AI/MI. There are several reasons for this continuing situation:

Understanding the requirements.

Which RAGAGEPs are relevant?

Common difficulties with mechanical integrity.

The impacts of process safety culture.
River conversations: A confluence of lessons and emergence from the Taieri River and the Nechako River
Authors: Parkes Margot W.
Published: December 2021

Drawing on ongoing patterns of learning and relationship, this paper offers a reflection and acknowledgement on the notable influence of two rivers and their role as respected and highly valued “eco‐social elders”: The Taieri River in Otago, New Zealand, and the Nechako River in northern British Columbia, Canada. The paper is motivated by the question: “If a river has ‘voice’, what can be learned from the emergence arising from rivers ‘in conversation’?”. At the heart of the reflection are the themes of confluence and emergence—ways in which we grasp the coming together of things, especially when that combination is more than the sum of their parts. The paper aims to explore a “conversation” between the river teachings of the Taieri River and the Nechako River, identifying examples of patterns and connections between distinct river “voices,” and how these may contribute to emergence and ongoing conversations among different rivers and their teachings. The paper commences with an introduction to both rivers, identifying points of direct comparison and contrast, then moving to explore themes of confluence, weaving and emergence, combining ecological, metaphorical, and personal perspectives. The conversation then progresses downstream to river–ocean relationships, reflecting on rivers as eco‐social elders that inspire conversations, provide a sense of home, and offer a point of reference to consider the wider influence on rivers and waterways on the health of diverse species within catchments and across the planet.
Evaluation of indirect and direct scoring methods to relate biochemical soil quality indicators to ecosystem services
Authors: Xia Yushu , Wander Michelle
Published: December 2021

Soil health assessments use scoring curves to quantify relationships between soil quality indicators (SQIs) and ecosystem services (ESSs). We evaluated methods for scoring curve development using three labile C pools (β‐glucosidase [BG], fluorescein diacetate [FDA] hydrolysis, and permanganate oxidizable carbon [POXC]). Concepts and methods for SQI interpretation used by established frameworks were assessed, with 129 studies reporting relationships to either soil organic C (SOC) (n = 367), a common surrogate for indirect estimation of ESSs, or direct measures of crop yield (n = 88), soil respiration (n = 66), and N2O and CH4 emissions (n = 51). Indirect assessment of BG using SOC and site covariates resolved tillage‐based differences (P < .05). Correlations between SOC and SQIs observed under different land uses suggested that use of SOC for indirect scoring would be more effective for FDA than POXC. Direct relationships were generally positive between SQIs and yield (89%), soil respiration (89%), and N2O and CH4 emissions (76%), but such relationships could be nonlinear. Direct assessment revealed that both positive and negative ESS outcomes increased with labile C fraction abundance that complicates the assignment of ESS‐based SQI scores. Although direct SQI scores are relatively easy to interpret, relationships between scores and SQIs can vary 10‐fold for different sites and cropping systems (upland versus rice paddy), which is much greater than treatment‐based differences observed within single sites. To quantify relationships between SQIs and ESS outcomes, one must measure influential site covariates (SQI–ESS covariates) along with details about management, sampling, and analysis.
Effect of Different Rotational Speeds of the Extruder on the Structure of Corn Starch
Authors: Dong Yuqing , Wang Bin , Fang Youxin , Xu Xin , Yan Shouxin , Cui Bo , Abd El‐Aty A. M.
Published: December 2021

In this study, corn starch samples that are treated at different rotational speeds (native corn starch, 5, 15, 25, 35, and 45 Hz) are prepared by twin‐screw extrusion, and the structure of corn starch is evaluated. The results show that the crystallinity, degree of order, and degree of the double helix of corn starch decrease with increasing screw speed. In addition, in the gelatinization performance test, the rotational speed is found to have a substantial effect on the peak viscosity, breakdown viscosity, final viscosity, and rebound viscosity. With increasing screw speed, the long‐branched chain of the corn starch sample changes into short branched chains, and the molecular weight distribution width index increases continuously. This study provides a theoretical basis for the large‐scale extrusion of corn starch.
Recent advances in high‐loading catalysts for low‐temperature fuel cells: From nanoparticle to single atom
Authors: Shen Lixiao , Ma Miao , Tu Fengdi , Zhao Zigang , Xia Yunfei , Goh Kokswee , Zhao Lei , Wang Zhenbo , Shao Guangjie
Published: December 2021

Low‐temperature fuel cells (LTFCs) are considered to be one of the most promising power sources for widespread application in sustainable and renewable energy conversion technologies. Although remarkable advances have been made in the mass activity of catalysts, mass transport impedance needs to be urgently addressed at a well‐designed membrane electrode assembly (MEA) scale. Increasing the loading of electrocatalysts is conducive to prepare thinner and more efficient MEAs owing to the resulting enhanced reactant permeability, better proton diffusion, and lower electrical resistance. Herein, recent progress in high‐loading (≥40 wt.%) Pt nanoparticle catalysts (NPCs) and high‐loading (≥2 wt.%) single‐atom catalysts (SACs) for LTFC applications are reviewed. A summary of various synthetic approaches and support materials for high‐loading Pt NPCs and SACs is systematically presented. The influences of high surface area and appropriate surface functionalization for Pt NPCs, as well as coordination environment, spatial confinement effect, and strong metal‐support interactions (SMSI) for SACs are highlighted. Additionally, this review presents some ideas regarding challenges and future opportunities of high‐loading catalysts in the application of LTFCs.
Prescribing cholinesterase inhibitors in mild cognitive impairment—Observations from the Alzheimer's Disease Neuroimaging Initiative
Authors: Stage Eddie , Svaldi Diana , Sokolow Sophie , Risacher Shannon L. , Marosi Krisztina , Rotter Jerome I. , Saykin Andrew J. , Apostolova Liana G. ,   for the Alzheimer's Disease Neuroimaging Initiative
Published: December 2021

Introduction

Analyses of off‐label use of acetylcholinesterase inhibitors (AChEIs) in mild cognitive impairment (MCI) has produced mixed results. Post hoc analyses of observational cohorts, such as the Alzheimer's Disease Neuroimaging Initiative (ADNI), have reported deleterious effects in AChEI‐treated subjects (AChEI+). Here, we used neuroimaging biomarkers to determine whether AChEI+ subjects had a greater rate of neurodegeneration than untreated (AChEI–) subjects while accounting for baseline differences.

Methods

We selected 121 ADNI MCI AChEI+ subjects and 151 AChEI– subjects with a magnetic resonance imaging (MRI) scan; 82 AChEI+ and 110 AChEI– also had a fluorodeoxyglucose (FDG) scan. A subset (83 AChEI+ and 98 AChEI–) had cerebrospinal fluid (CSF) or amyloid positron emission tomography (PET) assessment for amyloid positivity. Linear regression models were used to compare the effect of treatment on changes in Mini‐Mental State Examination and Clinical Dementia Rating‐Sum of Boxes scores. We used standard regression in SPM (for baseline) and the SPM toolbox sandwich estimator, SwE (for longitudinal) for comparisons of AChEI+ and AChEI– FDG PET and MRI data.

Results

At baseline, the AChEI+ group had significantly reduced cortical gray matter density (GMD) and more hypometabolism than AChEI– subjects. The greater rate of atrophy and hypometabolic changes over time in AChEI+ compared to AChEI– subjects did not survive correction for baseline differences. AChEI+ participants were more likely to be amyloid‐positive and have lower GMD and FDG standardized uptake value ratio than AChEI– at baseline. AChEI+ subjects showed greater atrophy over time, which remained significant after controlling for amyloid status.

Discussion

Our data suggest that the observed differences in rates of cognitive decline, atrophy, and hypometabolism are likely the result of significant baseline differences between the groups. Furthermore, the data indicate no treatment effect of AChEI (positive of negative), rather that physicians prescribe AChEI to subjects who present with more severe clinical impairment. This alone may account for the negative effect seen previously in the ADNI population of AChEI use among MCI subjects.
Novelty‐like activation of locus coeruleus protects against deleterious human pretangle tau effects while stress‐inducing activation worsens its effects
Authors: Omoluabi Tamunotonye , Torraville Sarah E. , Maziar Aida , Ghosh Abhinaba , Power Kyron D. , Reinhardt Camila , Harley Carolyn W. , Yuan Qi
Published: December 2021

The earliest abnormality associated with Alzheimer's disease (AD) is the presence of persistently phosphorylated pretangle tau in locus coeruleus (LC) neurons. LC neuron numbers and fiber density are positive predictors of cognition prior to death. Using an animal model of LC pretangle tau, we ask if LC activity patterns influence the sequelae of pretangle tau. We seeded LC neurons with a pretangle human tau gene. We provided daily novelty‐ or stress‐associated optogenetic activation patterns to LC neurons for 6 weeks in mid‐adulthood and, subsequently, probed cognitive and anatomical changes. Prior LC phasic stimulation prevented spatial and olfactory discrimination deficits and preserved LC axonal density. A stress‐associated activation pattern increased indices of anxiety and depression, did not improve cognition, and worsened LC neuronal health. These results argue that variations in environmental experiences associated with differing LC activity patterns may account for individual susceptibility to development of AD in humans.
Genetic diversity and structure of captive gentoo penguin populations in Japan
Authors: Aoki Yuna , Zaitsu Yosuke , Kurita Masanori , Phillips Richard A. , Tadano Ryo
Published: December 2021

Until the last decade, gentoo penguins were usually split into two subspecies, northern gentoo penguins (Pygoscelis papua papua) breeding in the Falkland Islands, South Georgia, and other subantarctic islands and southern gentoo penguins (P. papua ellsworthi) breeding in the South Sandwich, South Orkney and South Shetland islands, and Antarctic Peninsula. Recent genetics research, however, suggests that the population at South Georgia is much more closely related to those further south and should be included in P. papua ellsworthi. In Japanese zoos and aquariums, captive breeding of gentoo penguins is conducted separately in three populations: “Captive‐South Georgia,” originating from South Georgia, “Captive‐South Shetlands,” originating from South Shetlands, and “Captive‐Unknown,” originating from at least one founder of unknown subspecies. The aims of the present study were to investigate the genetic diversity and differentiation of these captive populations using microsatellite analysis. Genetic diversity in each captive population was similar to that found in the wild, although they had much lower contemporary effective population sizes. Pairwise genetic differentiation indexes (FST) among the three captive populations were as follows: 0.0309 (“Captive‐South Georgia” and “Captive‐Unknown”), 0.1094 (“Captive‐South Georgia” and “Captive‐South Shetlands”), and 0.1214 (“Captive‐South Shetlands” and “Captive‐Unknown”). Using Bayesian clustering, there was relatively high genetic differentiation between the “Captive‐South Shetlands” group, which formed a distinct cluster, and individuals of the “Captive‐Unknown” group, which were assigned to clusters in common with “Captive‐South Georgia.” The results from the present study are useful for future management of captive gentoo penguin populations in Japan.
Two-photon exchange in leptophilic dark matter scenarios
Authors: Garani Raghuveer , Gasparotto Federico , Mastrolia Pierpaolo , Munch Henrik J. , Palomares-Ruiz Sergio , Primo Amedeo
Published: December 2021

Abstract

In leptophilic scenarios, dark matter interactions with nuclei, relevant for direct detection experiments and for the capture by celestial objects, could only occur via loop-induced processes. If the mediator is a scalar or pseudo-scalar particle, which only couples to leptons, the dominant contribution to dark matter-nucleus scattering would take place via two-photon exchange with a lepton triangle loop. The corresponding diagrams have been estimated in the literature under different approximations. Here, we present new analytical calculations for one-body two-loop and two-body one-loop interactions. The two-loop form factors are presented in closed analytical form in terms of generalized polylogarithms up to weight four. In both cases, we consider the exact dependence on all the involved scales, and study the dependence on the momentum transfer. We show that some previous approximations fail to correctly predict the scattering cross section by several orders of magnitude. Moreover, we quantitatively show that form factors in the range of momentum transfer relevant for local galactic dark matter, can be significantly smaller than their value at zero momentum transfer, which is the approach usually considered.
Esc peptides as novel potentiators of defective cystic fibrosis transmembrane conductance regulator: an unprecedented property of antimicrobial peptides
Authors: Ferrera Loretta , Cappiello Floriana , Loffredo Maria Rosa , Puglisi Elena , Casciaro Bruno , Botta Bruno , Galietta Luis J. V. , Mori Mattia , Mangoni Maria Luisa
Published: December 2021

Mutations in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein lead to persistent lung bacterial infections, mainly due to Pseudomonas aeruginosa, causing loss of respiratory function and finally death of people affected by CF. Unfortunately, even in the era of CFTR modulation therapies, management of pulmonary infections in CF remains highly challenging especially for patients with advanced stages of lung disease. Recently, we identified antimicrobial peptides (AMPs), namely Esc peptides, with potent antipseudomonal activity. In this study, by means of electrophysiological techniques and computational studies we discovered their ability to increase the CFTR-controlled ion currents, by direct interaction with the F508del-CFTR mutant. Remarkably, this property was not explored previously with any AMPs or peptides in general. More interestingly, in contrast with clinically used CFTR modulators, Esc peptides would give particular benefit to CF patients by combining their capability to eradicate lung infections and to act as promoters of airway wound repair with their ability to ameliorate the activity of the channel with conductance defects. Overall, our findings not only highlighted Esc peptides as the first characterized AMPs with a novel property, that is the potentiator activity of CFTR, but also paved the avenue to investigate the functions of AMPs and/or other peptide molecules, for a new up-and-coming pharmacological approach to address CF lung disease.
Ethoxy acetalated dextran-based nanocarriers accomplish efficient inhibition of leukotriene formation by a novel FLAP antagonist in human leukocytes and blood
Authors: Kretzer Christian , Shkodra Blerina , Klemm Paul , Jordan Paul M. , Schröder Daniel , Cinar Gizem , Vollrath Antje , Schubert Stephanie , Nischang Ivo , Hoeppener Stephanie , Stumpf Steffi , Banoglu Erden , Gladigau Frederike , Bilancia Rossella , Rossi Antonietta , Eggeling Christian , Neugebauer Ute , Schubert Ulrich S. , Werz Oliver
Published: December 2021

Leukotrienes are pro-inflammatory lipid mediators generated by 5-lipoxygenase aided by the 5-lipoxygenase-activating protein (FLAP). BRP-201, a novel benzimidazole-based FLAP antagonist, inhibits leukotriene biosynthesis in isolated leukocytes. However, like other FLAP antagonists, BRP-201 fails to effectively suppress leukotriene formation in blood, which limits its therapeutic value. Here, we describe the encapsulation of BRP-201 into poly(lactide-co-glycolide) (PLGA) and ethoxy acetalated dextran (Ace-DEX) nanoparticles (NPs), aiming to overcome these detrimental pharmacokinetic limitations and to enhance the bioactivity of BRP-201. NPs loaded with BRP-201 were produced via nanoprecipitation and the physicochemical properties of the NPs were analyzed in-depth using dynamic light scattering (size, dispersity, degradation), electrophoretic light scattering (effective charge), NP tracking analysis (size, dispersity), scanning electron microscopy (size and morphology), UV–VIS spectroscopy (drug loading), an analytical ultracentrifuge (drug release, degradation kinetics), and Raman spectroscopy (chemical attributes). Biological assays were performed to study cytotoxicity, cellular uptake, and efficiency of BRP-201-loaded NPs versus free BRP-201 to suppress leukotriene formation in primary human leukocytes and whole blood. Both PLGA- and Ace-DEX-based NPs were significantly more efficient to inhibit leukotriene formation in neutrophils versus free drug. Whole blood experiments revealed that encapsulation of BRP-201 into Ace-DEX NPs strongly increases its potency, especially upon pro-longed (≥ 5 h) incubations and upon lipopolysaccharide-challenge of blood. Finally, intravenous injection of BRP-201-loaded NPs significantly suppressed leukotriene levels in blood of mice in vivo. These results reveal the feasibility of our pharmacological approach using a novel FLAP antagonist encapsulated into Ace-DEX-based NPs with improved efficiency in blood to suppress leukotriene biosynthesis.
eNOS controls angiogenic sprouting and retinal neovascularization through the regulation of endothelial cell polarity
Authors: Smith Tracy L. , Oubaha Malika , Cagnone Gael , Boscher Cécile , Kim Jin Sung , El Bakkouri Yassine , Zhang Ying , Chidiac Rony , Corriveau Jeanne , Delisle Chantal , Andelfinger Gregor U. , Sapieha Przemyslaw , Joyal Jean-Sébastien , Gratton Jean-Philippe
Published: December 2021

The roles of nitric oxide (NO) and endothelial NO synthase (eNOS) in the regulation of angiogenesis are well documented. However, the involvement of eNOS in the sprouting of endothelial tip-cells at the vascular front during sprouting angiogenesis remains poorly defined. In this study, we show that downregulation of eNOS markedly inhibits VEGF-stimulated migration of endothelial cells but increases their polarization, as evidenced by the reorientation of the Golgi in migrating monolayers and by the fewer filopodia on tip cells at ends of sprouts in endothelial cell spheroids. The effect of eNOS inhibition on EC polarization was prevented in Par3-depleted cells. Importantly, downregulation of eNOS increased the expression of polarity genes, such as PARD3B, PARD6A, PARD6B, PKCΖ, TJP3, and CRB1 in endothelial cells. In retinas of eNOS knockout mice, vascular development is retarded with decreased vessel density and vascular branching. Furthermore, tip cells at the extremities of the vascular front have a marked reduction in the number of filopodia per cell and are more oriented. In a model of oxygen-induced retinopathy (OIR), eNOS deficient mice are protected during the initial vaso-obliterative phase, have reduced pathological neovascularization, and retinal endothelial tip cells have fewer filopodia. Single-cell RNA sequencing of endothelial cells from OIR retinas revealed enrichment of genes related to cell polarity in the endothelial tip-cell subtype of eNOS deficient mice. These results indicate that inhibition of eNOS alters the polarity program of endothelial cells, which increases cell polarization, regulates sprouting angiogenesis and normalizes pathological neovascularization during retinopathy.