bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuroprotective Natural Products for Alzheimer’s Disease
Authors: Chen Xin , Drew Joshua , Berney Wren , Lei Wei
Published: May 2021

Alzheimer’s disease (AD) is the number one neurovegetative disease, but its treatment options are relatively few and ineffective. In efforts to discover new strategies for AD therapy, natural products have aroused interest in the research community and in the pharmaceutical industry for their neuroprotective activity, targeting different pathological mechanisms associated with AD. A wide variety of natural products from different origins have been evaluated preclinically and clinically for their neuroprotective mechanisms in preventing and attenuating the multifactorial pathologies of AD. This review mainly focuses on the possible neuroprotective mechanisms from natural products that may be beneficial in AD treatment and the natural product mixtures or extracts from different sources that have demonstrated neuroprotective activity in preclinical and/or clinical studies. It is believed that natural product mixtures or extracts containing multiple bioactive compounds that can work additively or synergistically to exhibit multiple neuroprotective mechanisms might be an effective approach in AD drug discovery.
Serum miRNAs Support the Indication for MRI-Ultrasound Fusion-Guided Biopsy of the Prostate in Patients with Low-PI-RADS Lesions
Authors: Keck Bastian , Borkowetz Angelika , Poellmann Julia , Jansen Thilo , Fischer Moritz , Fuessel Susanne , Kahlmeyer Andreas , Wirth Manfred , Huber Johannes , Cavallaro Alexander , Hammon Matthias , Platzek Ivan , Hartmann Arndt , Baretton Gustavo , Kunath Frank , Sikic Danijel , Taubert Helge , Wullich Bernd , Erdmann Kati , Wach Sven
Published: May 2021

Multiparametric MRI (mpMRI) and targeted biopsy of the prostate enhance the tumor detection rate. However, the prediction of clinically significant prostate cancer (PCa) is still limited. Our study tested the additional value of serum levels of selected miRNAs in combination with clinical and mpMRI information for PCa prediction and classification. A total of 289 patients underwent targeted mpMRI-ultrasound fusion-guided prostate biopsy complemented by systematic biopsy. Serum miRNA levels of miRNAs (miR-141, miR-375, miR-21-5p, miR-320b, miR-210-3p, let-7c, and miR-486) were determined by quantitative PCR. Detection of any PCa and of significant PCa were the outcome variables. The patient age, pre-biopsy PSA level, previous biopsy procedure, PI-RADS score, and serum miRNA levels were covariates for regularized binary logistic regression models. The addition of miRNA expression of miR-486 and let-7c to the baseline model, containing only clinical parameters, increased the predictive accuracy. Particularly in patients with PI-RADS ≤3, we determined a sensitivity for detecting significant PCa (Gleason score ≥ 7a corresponding to Grade group ≥2) of 95.2%, and an NPV for absence of significant PCa of 97.1%. This accuracy could be useful to support patient counseling in selected cases.
Effects of FGFR Tyrosine Kinase Inhibition in OLN-93 Oligodendrocytes
Authors: Rajendran Ranjithkumar , Böttiger Gregor , Dentzien Niklas , Rajendran Vinothkumar , Sharifi Bischand , Ergün Süleyman , Stadelmann Christine , Karnati Srikanth , Berghoff Martin
Published: May 2021

Fibroblast growth factor (FGF) signaling is involved in the pathogenesis of multiple sclerosis (MS). Data from neuropathology studies suggest that FGF signaling contributes to the failure of remyelination in MS. In MOG35–55-induced EAE, oligodendrocyte-specific deletion of FGFR1 and FGFR2 resulted in a less severe disease course, reduced inflammation, myelin and axon degeneration and changed FGF/FGFR and BDNF/TrkB signaling. Since signaling cascades in oligodendrocytes could not be investigated in the EAE studies, we here aimed to characterize FGFR-dependent oligodendrocyte-specific signaling in vitro. FGFR inhibition was achieved by application of the multi-kinase-inhibitor dovitinib and the FGFR1/2/3-inhibitor AZD4547. Both substances are potent inhibitors of FGF signaling; they are effective in experimental tumor models and patients with malignancies. Effects of FGFR inhibition in oligodendrocytes were studied by immunofluorescence microscopy, protein and gene analyses. Application of the tyrosine kinase inhibitors reduced FGFR1, phosphorylated ERK and Akt expression, and it enhanced BDNF and TrkB expression. Furthermore, the myelin proteins CNPase and PLP were upregulated by FGFR inhibition. In summary, inhibition of FGFR signaling in oligodendrocytes can be achieved by application of tyrosine kinase inhibitors. Decreased phosphorylation of ERK and Akt is associated with an upregulation of BDNF/TrkB signaling, which may be responsible for the increased production of myelin proteins. Furthermore, these data suggest that application of FGFR inhibitors may have the potential to promote remyelination in the CNS.
Nipah Virus Efficiently Replicates in Human Smooth Muscle Cells without Cytopathic Effect
Authors: DeBuysscher Blair L. , Scott Dana P. , Rosenke Rebecca , Wahl Victoria , Feldmann Heinz , Prescott Joseph
Published: May 2021

Nipah virus (NiV) is a highly pathogenic zoonotic virus with a broad species tropism, originating in pteropid bats. Human outbreaks of NiV disease occur almost annually, often with high case-fatality rates. The specific events that lead to pathogenesis are not well defined, but the disease has both respiratory and encephalitic components, with relapsing encephalitis occurring in some cases more than a year after initial infection. Several cell types are targets of NiV, dictated by the expression of the ephrin-B2/3 ligand on the cell’s outer membrane, which interact with the NiV surface proteins. Vascular endothelial cells (ECs) are major targets of infection. Cytopathic effects (CPE), characterized by syncytia formation and cell death, and an ensuing vasculitis, are a major feature of the disease. Smooth muscle cells (SMCs) of the tunica media that line small blood vessels are infected in humans and animal models of NiV disease, although pathology or histologic changes associated with antigen-positive SMCs have not been reported. To gain an understanding of the possible contributions that SMCs might have in the development of NiV disease, we investigated the susceptibility and potential cytopathogenic changes of human SMCs to NiV infection in vitro. SMCs were permissive for NiV infection and resulted in high titers and prolonged NiV production, despite a lack of cytopathogenicity, and in the absence of detectable ephrin-B2/3. These results indicate that SMC might be important contributors to disease by producing progeny NiV during an infection, without suffering cytopathogenic consequences.
Compact Miniaturized Bioluminescence Sensor Based on Continuous Air-Segmented Flow for Real-Time Monitoring: Application to Bile Salt Hydrolase (BSH) Activity and ATP Detection in Biological Fluids
Authors: Roda Aldo , Greco Pierpaolo , Simoni Patrizia , Marassi Valentina , Moroni Giada , Gioiello Antimo , Roda Barbara
Published: May 2021

A simple and versatile continuous air-segmented flow sensor using immobilized luciferase was designed as a general miniaturized platform based on sensitive biochemiluminescence detection. The device uses miniaturized microperistaltic pumps to deliver flows and compact sensitive light imaging detectors based on BI-CMOS (smartphone camera) or CCD technology. The low-cost components and power supply make it suitable as out-lab device at point of need to monitor kinetic-related processes or ex vivo dynamic events. A nylon6 flat spiral carrying immobilized luciferase was placed in front of the detector in lensless mode using a fiber optic tapered faceplate. ATP was measured in samples collected by microdialysis from rat brain with detecting levels as low as 0.4 fmoles. The same immobilized luciferase was also used for the evaluation of bile salt hydrolase (BSH) activity in intestinal microbiota. An aminoluciferin was conjugatated with chenodeoxycholic acid forming the amide derivative aLuc-CDCA. The hydrolysis of the aLuc-CDCA probe by BSH releases free uncaged aminoluciferin which is the active substrate for luciferase leading to light emission. This method can detect as low as 0.5 mM of aLuc-CDCA, so it can be used on real faecal human samples to study BSH activity and its modulation by diseases and drugs.
Validity and Reliability of the Arabic Version of the Psychosocial Impact of Dental Aesthetics Questionnaire for Yemeni Adolescents
Authors: Alsanabani Amal A. M. , Yusof Zamros Y. M. , Wan Hassan Wan Nurazreena , Aldhorae Khalid , Alyamani Helmi A.
Published: May 2021

(1) Objectives: This paper aimed to cross-culturally adapt the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) into an Arabic language version (PIDAQ(A)) for measuring the oral health related quality of life related to dental aesthetics among 12–17-year-old Yemeni adolescents. (2) Material and methods: The study comprised three parts, which were linguistic validation and qualitative interview, comprehensibility assessment, and psychometric validations. Psychometric properties were examined for validity (exploratory factor analysis (EFA), partial confirmatory factor analysis (PCFA), construct, criterion, and discriminant validity) and reliability (internal consistency and reproducibility). (3) Results: The PIDAQ(A) contained a new item. EFA extracted three factors (item factor loading 0.375 to 0.918) comprising dental self-confidence, aesthetic concern, and psychosocial impact subscales. PCFA showed good fit statistics (comparative fit index (CFI) = 0.928, root-mean-square error of approximation (RMSEA) = 0.071). In addition, invariance across age groups was tested. Cronbach’s α values ranged from 0.90 to 0.93 (intraclass correlations = 0.89–0.96). A criterion validity test showed that the PIDAQ(A) had a significant association with oral impacts on daily performance scores. A construct validity test showed significant associations between PIDAQ(A) subscales and self-perceived dental appearance and self-perceived need for orthodontic braces (p < 0.05). Discriminant validity presented significant differences in the mean PIDAQ(A) scores between subjects having severe malocclusion and those with slight malocclusion. No floor or ceiling effects were detected.
Surface Characterization of Fracture in Polylactic Acid vs. PLA + Particle (Cu, Al, Graphene) Insertions by 3D Fused Deposition Modeling Technology
Authors: Ghiban Brândușa , Pascu Nicoleta Elisabeta , Antoniac Iulian Vasile , Jiga Gabriel , Milea Claudia , Petre Gabriela , Gheorghe Cristina , Munteanu Corneliu , Istrate Bogdan
Published: May 2021

Polylactic acid (PLA) is one of the most extensively used biodegradable aliphatic polyester produced from renewable resources, such as corn starch. Due to its qualities, PLA is a leading biomaterial for numerous applications in medicine as well as in industry, replacing conventional petrochemical–based polymers. The purpose of this paper is to highlight the fracture behavior of pure PLA specimens in comparison with PLA particle insertions, (copper, aluminum and Graphene), after evaluation the mechanical properties, as well as the influence of filament angle deposition on these properties. In order to check if the filling density of the specimen influences the ultimate tensile stress (UTS), three different filling percentages (60%, 80%, and 100%) have been chosen in the experimental tests. A hierarchy concerning elongation / fiber heights after tensile testing was done. So, the highest elongation values were for simple PLA (about 4.1%), followed by PLA + Al insertion (3.2%–4%), PLA + graphene insertion (2.6%–4%) and the lowest values being for PLA with copper insertion (1.8%–2.7%). Regarding the fiber heights after fracture, the hierarchy was: the highest values was for PLA, then PLA + Al, PLA + grapheme and PLA + Cu. Finally, a correlation between fracture surfaces appearance and mechanical properties were established, being formulated the mechanism of fracture in according with filament angle deposition. Also, it was proposed a new method of evaluation of the fractured surface by measuring the dimensions of the filaments after printing Fused Deposition Modeling (FDM) and tensile testing.
Plasma Electrolytic Oxidation Ceramic Coatings on Zirconium (Zr) and ZrAlloys: Part I—Growth Mechanisms, Microstructure, and Chemical Composition
Authors: Attarzadeh Navid , Ramana Chintalapalle V.
Published: May 2021

Recently, a significant number of research projects have been directed towards designing and developing ceramic coatings for zirconium-based substrates due to their outstanding surface properties and utilization in modern technologies. The plasma electrolytic oxidation (PEO) coating is an environmentally friendly wet coating method that can be performed in a wide range of electrolytes. The surface characteristics of PEO coatings can be tailored by changing electrochemical parameters, electrolyte composition, and substrate alloying elements to adopt a conformal and adhesive PEO ceramic coating for the final demanding applications in chemical, electronics, and energy technologies. This review focuses on deriving a deeper fundamental understanding of the PEO growth mechanisms and the effect of process parameters on transient discharge behavior at breakdown, initiation, and growth of the oxide layer and incorporating species from the electrolyte. It highlights the fundamental microstructural properties associated with structural defects, phase transformation, and the role of additives.
Insect Chitin-Based Nanomaterials for Innovative Cosmetics and Cosmeceuticals
Authors: Triunfo Micaela , Tafi Elena , Guarnieri Anna , Scieuzo Carmen , Hahn Thomas , Zibek Susanne , Salvia Rosanna , Falabella Patrizia
Published: May 2021

Chitin and its derivatives are attracting great interest in cosmetic and cosmeceutical fields, thanks to their antioxidant and antimicrobial properties, as well as their biocompatibility and biodegradability. The classical source of chitin, crustacean waste, is no longer sustainable and fungi, a possible alternative, have not been exploited at an industrial scale yet. On the contrary, the breeding of bioconverting insects, especially of the Diptera Hermetia illucens, is becoming increasingly popular worldwide. Therefore, their exoskeletons, consisting of chitin as a major component, represent a waste stream of facilities that could be exploited for many applications. Insect chitin, indeed, suggests its application in the same fields as the crustacean biopolymer, because of its comparable commercial characteristics. This review reports several cosmetic and cosmeceutical applications based on chitin and its derivatives. In this context, chitin nanofibers and nanofibrils, produced from crustacean waste, have proved to be excellent cosmeceutical active compounds and carriers of active ingredients in personal care. Consequently, the insect-based chitin, its derivatives and their complexes with hyaluronic acid and lignin, as well as with other chitin-derived compounds, may be considered a new appropriate potential polymer to be used in cosmetic and cosmeceutical fields.
Hydrogenation of HOPG-Supported Gold Nanoparticles: Surface or Volume?
Authors: Sarvadii Sergey Yu. , Gatin Andrey K. , Dokhlikova Nadezhda V. , Kharitonov Vasiliy A. , Ozerin Sergey A. , Doronin Sergey V. , Grishin Maxim V. , Shub Boris R.
Published: May 2021

The hydrogenation features of gold nanoparticles deposited on highly oriented pyrolytic graphite were determined, and composite nanostructures consisting of pure and hydrogenized gold were synthesized. Methods of scanning tunneling microscopy and spectroscopy have been successfully used to probe the bottom of the conductive band and to determine the shape of the electron energy barrier in hydrogenized gold. Considering models of surface and volume hydrogenation, we have shown that no hydrogen dissolution occurred in gold nanoparticles, but all changes in their electronic structure were associated with surface processes. The results of the quantum chemical simulation also corresponded with this conclusion.
Central Nervous System Involvement in Trichinellosis: A Systematic Review
Authors: Rosca Elena Cecilia , Tudor Raluca , Cornea Amalia , Simu Mihaela
Published: May 2021

We reviewed the evidence on features of central nervous system (CNS) involvement in trichinellosis, systematically searching five databases (to January 2021). We categorized clinical features based on their diagnostic value as warning signs for severe CNS infection (with outcome death) or non-specific signs (outcome improvement). They were suggestive of severe infection if they substantially raised death probability. The review included 87 papers published from 1906 through 2019, with data on 168 patients. Mydriasis, paraparesis, dysphagia, psychomotor seizures, or delirium present a 30–45% increased death likelihood. The best poor prognosis predictor is mydriasis (positive likelihood ratio 9.08). Slow/absent light reflex, diminished/absent knee reflexes, globally decreased tendon reflexes present a moderate increase (20–25%) of death risk. Anisocoria, acalculia, or seizures could also indicate an increased death risk. We provided a detailed presentation of clinical and paraclinical signs that alert physicians of a possible neurotrichinellosis, emphasizing signs that might indicate a poor prognosis.
Subway Gearbox Fault Diagnosis Algorithm Based on Adaptive Spline Impact Suppression
Authors: Hu Zhongshuo , Yang Jianwei , Yao Dechen , Wang Jinhai , Bai Yongliang
Published: May 2021

In the signal processing of real subway vehicles, impacts between wheelsets and rail joint gaps have significant negative effects on the spectrum. This introduces great difficulties for the fault diagnosis of gearboxes. To solve this problem, this paper proposes an adaptive time-domain signal segmentation method that envelopes the original signal using a cubic spline interpolation. The peak values of the rail joint gap impacts are extracted to realize the adaptive segmentation of gearbox fault signals when the vehicle was moving at a uniform speed. A long-time and unsteady signal affected by wheel–rail impacts is segmented into multiple short-term, steady-state signals, which can suppress the high amplitude of the shock response signal. Finally, on this basis, multiple short-term sample signals are analyzed by time- and frequency-domain analyses and compared with the nonfaulty results. The results showed that the method can efficiently suppress the high-amplitude components of subway gearbox vibration signals and effectively extract the characteristics of weak faults due to uniform wear of the gearbox in the time and frequency domains. This provides reference value for the gearbox fault diagnosis in engineering practice.
Intangible Assets and Labor Productivity Growth
Authors: Hintzmann Carolina , Lladós-Masllorens Josep , Ramos Raul
Published: May 2021

We examine the contribution to labor productivity growth in the manufacturing sector of investment in different intangible asset categories—computerized information, innovative property, and economic competencies—for a set of 18 European countries between 1995 and 2017, as well as whether this contribution varies between different groups of countries. The motivation is to go a step further and identify which single or combination of intangible assets are relevant. The main findings can be summarized as follows. Firstly, all the three different categories of intangible assets contribute to labor productivity growth. In particular, intangible assets related to economic competences together with innovative property assets have been identified as the main drivers; specifically, advertising and marketing, organizational capital, research and development (R&D) investment, and design. Secondly, splitting the sample of European Union (EU) member states into three groups—northern, central and southern Europe—allows for the identification of a significant differentiated behavior between and within groups, in terms of the effects of investment in intangible assets on labor productivity growth. We conclude that measures promoting investment in intangibles at EU level should be accompanied by specific measures focusing on each country’s needs, for the purpose of promoting labor productivity growth. The obtained evidence suggests that the solution for the innovation deficit of some European economies consist not only of raising R&D expenditure, but also exploiting complementarities between different types of assets.
Evidence-Informed Teaching: Investigating Whether Evidence from ‘Flipping the Classroom’ Research Improves Students’ Motivation for Mathematics
Authors: Dierdorp Adri
Published: May 2021

This study from 2019 investigates whether the impact on a STEM teacher’s evidence-informed teaching approach using the evidence of flipping the classroom research improves students’ (13–14 years old) motivation in a Dutch setting and if this approach allows students to perform better. We report this approach in line with the cycle of expansive learning of Engeström. We asked: “To what extent can evidence based on the flipping the classroom approach improve the motivation and results of grade 8 preuniversity track students doing mathematics?”, followed by the subquestions: “To what extent does education by the FtCA increase student motivation?” and “To what extent does education by the FtCA ensure better test results for students?”. A questionnaire is used to investigate to what extent the motivation of students increased, and a teacher is interviewed about his experiences with the “flipping the classroom” model. To test whether the results have improved, a pre- and post-test is taken and analyzed. A significant increase in both intrinsic and extrinsic motivation has been found, and students gained a stronger sense of autonomy, competence, and belonging. The test results improved, but the difference is not statistically significant. However, despite the disappointing test results, the teacher was very positive about the new way of working.
A Short Review on Electrochemical Sensing of Commercial Dyes in Real Samples Using Carbon Paste Electrodes
Authors: Soni Isha , Kumar Pankaj , Sharma Shruti , Kudur Jayaprakash Gururaj
Published: May 2021

Synthetic dyes are commonly used in food products like soft drinks, vegetable sauces, jellies, etc. Most artificial dyes can cause cancer, therefore it is very important to develop sensors to detect them in food samples. Voltammetric methods with carbon paste electrodes (CPEs) are promising for this purpose. However, modification of CPEs is necessary to detect the commercial dyes in food samples in the presence of interferents. In the current review, we have discussed the different previous research in which detection of dyes is performed in real samples with good detection limits. The current review will be helpful for readers who are interested in developing low-cost electrodes for the effective determination of dyes in commercial products like soft drinks and vegetable sauces.
An Investigation into the Potential of Hosting Capacity and the Frequency Stability of a Regional Grid with Increasing Penetration Level of Large-Scale PV Systems
Authors: Alshahrani Abdullah , Omer Siddig , Su Yuehong
Published: May 2021

It is widely believed that the incorporation of renewable energy to the current power grid is the way forward in achieving sustainable power generation. Currently, with the reduction of PV prices, many countries have started connecting PV systems into their grid network, hence leading to a sharp increase of the penetration levels of renewable electricity production. This will bring significant change in the load pattern and the ramping requirements of the grid’s conventional generation system due to the varying nature of the renewable energy generation. This significant change affects the stability of the grid frequency because it becomes more challenging for the system operators to maintain the equilibrium between the generation and load. Additionally, this significant change affects the PV system potential hosting capacity of the traditional grid because of the PV system’s curtailment in order to comply with the constraints of the grid’s conventional generation system. In this paper, the net load, grid frequency stability, and grid potential hosting capacity are evaluated in the situation of increasing the penetration level of large-scale PV systems generation into the grid. The results show that the grid operators will face increasingly variable net load patterns and steeper ramping events as the PV system penetration level increases. Additionally, the results show the requirement of having flexibility measures that target each grid constraint as the PV system penetration level increases.
Deep Learning-Based Intrusion Detection for Distributed Denial of Service Attack in Agriculture 4.0
Authors: Ferrag Mohamed Amine , Shu Lei , Djallel Hamouda , Choo Kim-Kwang Raymond
Published: May 2021

Smart Agriculture or Agricultural Internet of things, consists of integrating advanced technologies (e.g., NFV, SDN, 5G/6G, Blockchain, IoT, Fog, Edge, and AI) into existing farm operations to improve the quality and productivity of agricultural products. The convergence of Industry 4.0 and Intelligent Agriculture provides new opportunities for migration from factory agriculture to the future generation, known as Agriculture 4.0. However, since the deployment of thousands of IoT based devices is in an open field, there are many new threats in Agriculture 4.0. Security researchers are involved in this topic to ensure the safety of the system since an adversary can initiate many cyber attacks, such as DDoS attacks to making a service unavailable and then injecting false data to tell us that the agricultural equipment is safe but in reality, it has been theft. In this paper, we propose a deep learning-based intrusion detection system for DDoS attacks based on three models, namely, convolutional neural networks, deep neural networks, and recurrent neural networks. Each model’s performance is studied within two classification types (binary and multiclass) using two new real traffic datasets, namely, CIC-DDoS2019 dataset and TON_IoT dataset, which contain different types of DDoS attacks.
Low-Power Two-Phase Clocking Adiabatic PUF Circuit
Authors: Monteiro Câncio , Takahashi Yasuhiro
Published: May 2021

Internet of Things (IoT) has enabled battery-powered devices to transmit sensitive data, while presenting high power consumption and security issues. To address these challenges, adiabatic-based physical unclonable functions (PUFs) offer a promising solution for low-power and secure IoT device applications. In this study, we propose a novel low-power two-phase clocking adiabatic PUF. The proposed adiabatic PUF utilizes a trapezoidal power clock signal with a time-ramped voltage to achieve an improved energy efficiency and reliable start-up PUF behavior. Static CMOS logic is employed to produce stable challenge-response pairs (CRPs) in the adiabatic mode. The pull-down network is designed to control the PUF cell to charge and discharge its output nodes with a constant supply current during secure key generation. The body effect of PMOS transistors, ambient temperatures, and CMOS process variations are investigated to examine the uniqueness and reliability of the proposed work. The proposed adiabatic PUF is simulated using 0.18 µm CMOS process technology with a supply voltage of 1.8 V. The uniqueness and reliability of the proposed adiabatic PUF are 49.82% and 99.47%, respectively. In addition, it requires a start-up power of 0.47 µW and consumes an energy of 15.98 fJ/bit/cycle at the reference temperature of 27 °C.
An Integrated Multi-Approach to Environmental Monitoring of a Self-Burning Coal Waste Pile: The São Pedro da Cova Mine (Porto, Portugal) Study Case
Authors: Teodoro Ana , Santos Patrícia , Espinha Marques Jorge , Ribeiro Joana , Mansilha Catarina , Melo Armindo , Duarte Lia , Rodrigues de Almeida Cátia , Flores Deolinda
Published: May 2021

The São Pedro da Cova waste pile (Porto, Portugal) is composed of coal mining residues that have been self-burning since 2005 and is located close to an inhabited area and social infrastructures, further adding to effects on the environment and human health. Therefore, there is a great interest in the environmental monitoring of this waste pile. This work describes an integrative multi-approach that allows the environmental monitoring of several parameters of the waste pile, applying several technologies. The temperature measurements were obtained by a thermal infrared (TIR) sensor on board an unmanned aerial vehicle (UAV) and supplemented with field measurements. In order to evaluate the altimetric variations, for each flight, a digital elevation model (DEM) was generated considering a multispectral sensor also on board the UAV. The hydrogeochemical characterization was performed through the analysis of groundwater and surface water samples, with and without the influence of mine drainage. The soil monitoring included the analysis of waste material as well as the surface soil in the surrounding area of the waste pile. All the data were analyzed and integrated in a geographical information system (GIS) open-source application. The adopted multi-approach methodology, given its intrinsic interdisciplinary character, has proven to be an effective way of encompassing the complexity of this type of environmental problem.
Calcium Biogeochemical Cycle in a Typical Karst Forest: Evidence from Calcium Isotope Compositions
Authors: Han Guilin , Eisenhauer Anton , Zeng Jie , Liu Man
Published: May 2021

In order to better constrain calcium cycling in natural soil and in soil used for agriculture, we present the δ44/40Ca values measured in rainwater, groundwater, plants, soil, and bedrock samples from a representative karst forest in SW China. The δ44/40Ca values are found to differ by ≈3.0‰ in the karst forest ecosystem. The Ca isotope compositions and Ca contents of groundwater, rainwater, and bedrock suggest that the Ca of groundwater primarily originates from rainwater and bedrock. The δ44/40Ca values of plants are lower than that of soils, indicating the preferential uptake of light Ca isotopes by plants. The distribution of δ44/40Ca values in the soil profiles (increasing with soil depth) suggests that the recycling of crop-litter abundant with lighter Ca isotope has potential effects on soil Ca isotope composition. The soil Mg/Ca content ratio probably reflects the preferential plant uptake of Ca over Mg and the difference in soil maturity. Light Ca isotopes are more abundant in mature soils than nutrient-depleted soils. The relative abundance in the light Ca isotope (40Ca) is in the following order: farmland > burnt grassland > forests > grassland > shrubland. Our results further indicate that biological fractionation in a soil–plant system is a vital factor for Ca–geochemical transformations in soil surface systems.
Recovery of Forest Structure Following Large-Scale Windthrows in the Northwestern Amazon
Authors: Urquiza Muñoz J. David , Magnabosco Marra Daniel , Negrón-Juarez Robinson I. , Tello-Espinoza Rodil , Alegría-Muñoz Waldemar , Pacheco-Gómez Tedi , Rifai Sami W. , Chambers Jeffrey Q. , Jenkins Hillary S. , Brenning Alexander , Trumbore Susan E.
Published: May 2021

The dynamics of forest recovery after windthrows (i.e., broken or uprooted trees by wind) are poorly understood in tropical forests. The Northwestern Amazon (NWA) is characterized by a higher occurrence of windthrows, greater rainfall, and higher annual tree mortality rates (~2%) than the Central Amazon (CA). We combined forest inventory data from three sites in the Iquitos region of Peru, with recovery periods spanning 2, 12, and 22 years following windthrow events. Study sites and sampling areas were selected by assessing the windthrow severity using remote sensing. At each site, we recorded all trees with a diameter at breast height (DBH) ≥ 10 cm along transects, capturing the range of windthrow severity from old-growth to highly disturbed (mortality > 60%) forest. Across all damage classes, tree density and basal area recovered to >90% of the old-growth values after 20 years. Aboveground biomass (AGB) in old-growth forest was 380 (±156) Mg ha−1. In extremely disturbed areas, AGB was still reduced to 163 (±68) Mg ha−1 after 2 years and 323 (± 139) Mg ha−1 after 12 years. This recovery rate is ~50% faster than that reported for Central Amazon forests. The faster recovery of forest structure in our study region may be a function of its higher productivity and adaptability to more frequent and severe windthrows. These varying rates of recovery highlight the importance of extreme wind and rainfall on shaping gradients of forest structure in the Amazon, and the different vulnerabilities of these forests to natural disturbances whose severity and frequency are being altered by climate change.
Effects of Grain Pattern on the Rolling Shear Properties of Wood in Cross-Laminated Timber
Authors: Wu Guofang , Zhong Yong , Ren Haiqing
Published: May 2021

Rolling shear modulus and strength are the key factors affecting the mechanical performance of some wood products such as cross-laminated timber (CLT). As reported, rolling shear property strongly depends on the sawing pattern such as the aspect ratio and grain direction (grain mode). However, the mechanism behind this phenomenon has not yet been clarified. In this work, the rolling shear modulus and strength of spruce-pine-fir (SPF) with different grain modes and aspect ratios were experimentally investigated. In addition, a theoretical investigation was carried out to reveal the mechanism behind this phenomenon. The results exhibited that the rolling shear moduli of 0° and 90° grain-mode wood were the same. This value can be called the pure rolling shear modulus. Rolling shear modulus of wood with angles other than 0° and 90° can be calculated from the pure rolling shear modulus and grain angle. Therefore, this modulus can be called the apparent rolling shear modulus. Thus, using 0° and 90° grain-mode specimens to determine the pure rolling shear modulus and strength of wood is recommended.
Survival Rate, Chemical and Microbial Properties of Oak Seedlings Planted with or without Oak Forest Soils in a Black Locust Forest of a Dryland
Authors: Tatsumi Chikae , Taniguchi Takeshi , Hyodo Fujio , Du Sheng , Yamanaka Norikazu , Tateno Ryunosuke
Published: May 2021

Native tree species are frequently unable to effectively grow in non-native tree cultivation scenarios. In the Loess Plateau, China, it is difficult to find native oak (Quercus liaotungensis) seedlings in non-native black locust forests. Black locust is an arbuscular mycorrhizal (AM) tree, but oak is an ectomycorrhizal (ECM) tree. Plants highly depend on their symbiotic mycorrhizal fungi to take up water, nitrogen (N) and other nutrients. We hypothesized that black locust forests would not provide ECM inoculum to oak seedlings, limiting their water and nutrient uptake, which would be improved by ECM inoculum. Here, we (1) sowed seeds, with or without oak forest soils, (2) transplanted seedlings collected in oak forests, with or without oak forest soils, and (3) planted seedlings germinated in autoclaved or unautoclaved oak forest soils. We measured the survival and growth rate for all three experiments, along with chemical properties, and root ECM colonization. Oak seeds sowed with oak forest soils had higher mycorrhizal colonization, leaf N concentrations and survival rate, and lower root δ13C than the seeds sowed without oak forest soils. Planting with oak forest soils also increased the survival rate of the germinated seedlings, but not the transplanted seedlings. Overall, our study suggested that the use of oak forest soils in the black locust forest to improve the water and N uptake of oak seedlings by providing the ECM inoculum, resulting in a high survival rate. Our study also implies that the method of sowing seeds was effortless and effectively compared to transplanting wild/nursery seedlings.
Latewood Ring Width Reveals CE 1734 Felling Dates for Walker House Timbers in Tupelo, Mississippi, USA
Authors: Patterson Thomas W. , Harley Grant L. , Holt David H. , Doherty Raymond T. , King Daniel J. , Heeter Karen J. , Chasez Ashley L. , Crowell Alyssa C. , Stewart Ian M.
Published: May 2021

Dendroarchaeology is under-represented in the Gulf Coastal Plain region of the United States (US), and at present, only three published studies have precision dated a collection of 18th–19th-century structures. In this study, we examined the tree-ring data from pine, poplar, and oak timbers used in the Walker House in Tupelo, Mississippi. The Walker House was constructed ca. the mid-1800s with timbers that appeared to be recycled from previous structures. In total, we examined 30 samples (16 pines, 8 oaks, and 6 poplars) from the attic and crawlspace. We cross-dated latewood ring growth from the attic pine samples to the period 1541–1734 (r = 0.52, t = 8.43, p < 0.0001) using a 514-year longleaf pine (Pinus palustris Mill.) latewood reference chronology from southern Mississippi. The crawlspace oak samples produced a 57-year chronology that we dated against a white oak (Quercus alba L.) reference chronology from northeast Alabama to the period 1765–1822 (r = 0.36, t = 2.83, p < 0.01). We were unable to cross-date the six poplar samples due to a lack of poplar reference chronologies in the region. Our findings have two important implications: (1) the pine material dated to 1734 represents the oldest dendroarchaeology-confirmed dating match for construction materials in the southeastern US, and (2) cross-dating latewood growth for southeastern US pine species produced statistically significant results, whereas total ring width failed to produce significant dating results.
Research on Tree Pith Location in Radial Direction Based on Terrestrial Laser Scanning
Authors: Cao Yun , Wang Danyu , Wang Zewei , Tian Lijing , Zheng Change , Tian Ye , Liu Yi
Published: May 2021

Obtaining the direction of a diameter line through the tree pith is the basis of effective sampling by a micro-drill resistance instrument. In order to implement non-destructive tree pith location in the radial direction, the geometric property of tree pith, the longest chord through the tree pith on the cross-section will bisect outer contour circumference, as first proposed and proven in this paper. Based on this property, a non-destructive tree pith radial location method based on terrestrial laser scanning was developed. The experiments of pith radial location were made on the tree discs and the error of location is less than 1.5% for cross-section shape closed to ellipse on four tree species. The geometric property and location method of the tree pith in this research would play an important role in studying the growth process of standing trees, obtaining processed wood properties, and estimating tree age.
Sustainable Development Model of Performance of Woodworking Enterprises in the Czech Republic
Authors: Michal Jakub , Březina David , Šafařík Dalibor , Babuka Robert
Published: May 2021

The current requirements put on the Member States of the European Union (“EU”) in the area of sustainability and climate-neutral economy through strategic visions such as “Agenda 2030” or “A Clean planet for all” demonstrate the increasing need for quick identification of the changes required in the use of renewable and nonrenewable natural resources. Forests are a particular specific area of such changes. They represent a part of the ecosystem that is important for society from the economic, social, and environmental perspectives. Current climate changes have had a negative effect on the state of forestry in the Czech Republic and have raised many questions of how to ensure its sustainability. Besides the changes in forestry, the situation has also affected the sector primarily depending on the production function of forests and whose coexistence is conditioned. Taking specific sectors as examples, the article presents some prospects that could result in more efficient use of resources and defines potential synergic effects. Analyses of primary and secondary information sources were used to create preferential models (the term “preferential” in the context of the article represents opportunities through which it is possible to achieve an improvement in competitiveness and market advantage over the current model of wood processing and timber trade in the Czech Republic. The model works with potential perspectives and respects the challenges in the field of sustainable development) of timber and wood raw material production and processing and preferential and of economic efficiency (the term “efficiency” in the article represents the technical efficiency of the use of resources to achieve maximum economic benefit and added value. The aim is to increase the economic potential of individual sectors of primary and secondary processing in relation to timber sources) of woodworking businesses. The production model indicates that the energy use of wood, the expansion of the production mix in construction, the use of biomass and digestate in agroforestry, and the logging waste recovery are the most prospective sectors. The model presenting preferential areas in the woodworking industry development with respect to sustainability identified the need to increase associated production and material efficiency in construction and energy sectors, as well as insufficient activity of the sectors associated with technological innovations, FSC and PEFC certification prospects, bioeconomy and circular economy, a considerable need for wage growth in the sector and increased use of the existing production capacities by both domestic and foreign sales.
Spatiotemporal Changes in Vegetation Cover and Its Influencing Factors in the Loess Plateau of China Based on the Geographically Weighted Regression Model
Authors: Yang Chen , Fu Meichen , Feng Dingrao , Sun Yiyu , Zhai Guohui
Published: May 2021

Vegetation plays a key role in ecosystem regulation and influences our capacity for sustainable development. Global vegetation cover has changed dramatically over the past decades in response to both natural and anthropogenic factors; therefore, it is necessary to analyze the spatiotemporal changes in vegetation cover and its influencing factors. Moreover, ecological engineering projects, such as the “Grain for Green” project implemented in 1999, have been introduced to improve the ecological environment by enhancing forest coverage. In our study, we analyzed the changes in vegetation cover across the Loess Plateau of China and the impacts of influencing factors. First, we analyzed the latitudinal and longitudinal changes in vegetation coverage. Second, we displayed the spatiotemporal changes in vegetation cover based on Theil-Sen slope analysis and the Mann-Kendall test. Third, the Hurst exponent was used to predict future changes in vegetation coverage. Fourth, we assessed the relationship between vegetation cover and the influence of individual factors. Finally, ordinary least squares regression and the geographically weighted regression model were used to investigate the influence of various factors on vegetation cover. We found that the Loess Plateau showed large-scale greening from 2000 to 2015, though some regions showed decreasing vegetation cover. Latitudinal and longitudinal changes in vegetation coverage presented a net increase. Moreover, some areas of the Loess Plateau are at risk of degradation in the future, but most areas showed a sustainable increase in vegetation cover. Temperature, precipitation, gross domestic product (GDP), slope, cropland percentage, forest percentage, and built-up land percentage displayed different relationships with vegetation cover. Geographically weighted regression model revealed that GDP, temperature, precipitation, forest percentage, cropland percentage, built-up land percentage, and slope significantly influenced (p < 0.05) vegetation cover in 2000. In comparison, precipitation, forest percentage, cropland percentage, and built-up land percentage significantly affected (p < 0.05) vegetation cover in 2015. Our results enhance our understanding of the ecological and environmental changes in the Loess Plateau.
Assessing the Connectivity of Riparian Forests across a Gradient of Human Disturbance: The Potential of Copernicus “Riparian Zones” in Two Hydroregions
Authors: Fonseca André , Ugille Jean-Philippe , Michez Adrien , Rodríguez-González Patricia María , Duarte Gonçalo , Ferreira Maria Teresa , Fernandes Maria Rosário
Published: May 2021

The connectivity of riparian forests can be used as a proxy for the capacity of riparian zones to provide ecological functions, goods and services. In this study, we aim to test the potential of the freely available Copernicus “Riparian Zones” dataset to characterize the connectivity of riparian forests located in two European bioclimatic regions—the Mediterranean and the Central Baltic hydroregions—when subject to a gradient of human disturbance characterized by land-use/land-cover and hydromorphological pressures. We extracted riparian patches using the Copernicus “Actual Riparian Zone” (ARZ) layer and calculated connectivity using the Integral Index of Connectivity (IIC). We then compared the results with a “Manual Riparian Zone” (MRZ) layer, produced by manually digitizing riparian vegetation patches over a very high-resolution World Imagery layer. Our research evidenced reduced forest connectivity in both hydroregions, with the exception of Least Disturbed sites in the Central Baltic hydroregion. The ARZ layer exhibited overall suitability to assess the connectivity of riparian forests in the Central Baltic hydroregion, while the Mediterranean hydroregion displayed a consistent pattern of connectivity overestimation in all levels of human disturbance. To address this, we recommend some improvements in the spatial resolution and thematic accuracy of the Copernicus ARZ layer.
Coupling Vortical Bulk Flows to the Air–Water Interface: From Putting Oil on Troubled Waters to Surfactants on Protein Solutions
Authors: Hirsa Amir H. , Lopez Juan M.
Published: May 2021

The air–water interface in flowing systems remains a challenge to model, even in cases where the interface is essentially flat. This is because even though each side is governed by the Navier–Stokes equations, the stress balance which provides the boundary conditions for the equations involves properties associated with surfactants that are inevitably present at the air–water interface. Aside from challenges in measuring interfacial properties, either intrinsic or flow-dependent, the two-way coupling of bulk and interfacial flows is non-trivial, even for very simple flow geometries. Here, we present an overview of the physics associated with surfactant monolayers of flowing liquid and describe how the monolayer affects the bulk flow and how the monolayer is transported and deformed by the bulk flow. The emphasis is primarily on cylindrical flow geometries, and both Newtonian and non-Newtonian interfacial responses are considered. We consider interfacial flows that are solenoidal as well as those where the surface velocity is not divergence free.