bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Preparation and Performance of a Prefabricated Pervious-Cement-Based Concrete Pavement Slab
Authors: Zhai Hong-Xia , Li Chao-Fan , Liu Yun-Lin , Zhao Yue , Tang Yu-Zhao , Li Hai-Bin , Zheng Ji-Yuan
Published: June 2022

Based on the design of a prefabricated pervious composite cement concrete pavement slab, the interface properties and bending deformation properties of basalt pervious concrete (BPC) and PVA fiber base impervious concrete (PFBIC) composite specimens were studied. The effects of the different interfacial agents on the interfacial bonding performance were compared using a splitting tensile strength test and interfacial shear test. The deformation capacity of the composite specimens under bending load was tested using a three-point bending test, with the symmetry of the model considered and compared with the deformation capacity of the BPC specimen and PFBIC specimen. The results showed that the compressive strength of the BPC prepared using an orthogonal test reached 40.30 MPa, while the permeability coefficient was 2.41 mm/s. Different interface treatment processes determine the interface bonding properties. The best interface treatment method can induce the interface bonding strength to be higher than the strength of the BPC matrix itself, while the interface transition zone matrix will be denser without obvious microscopic defects. Under the bending tensile load, the ultimate bending stress reached 6.58 MPa and the maximum deflection in the midspan was 0.81 mm. As a protective layer, the PFBIC can alleviate the disadvantage of the insufficient strength of the BPC and can improve the bending ultimate bearing capacity of the BPC-PFBIC through its own stiffness.
Burr XII Distribution for Disease Data Analysis in the Presence of a Partially Observed Failure Mode
Authors: Almuhayfith Fatimah E. , Darwish Jumanah Ahmed , Alharbi Randa , Marin Marin
Published: June 2022

Modeling competing failure modes is an important problem in engineering and survival analyses. Competing failure modes are partially observed in many applications and often pose a modeling challenge. This study discusses the inference for partially observed failure modes assuming a Burr XII distribution. In particular, we consider two failure modes, and the failure time data are collected under a hybrid type I censoring scheme. The model parameters are estimated using maximum likelihood and Bayesian methods under a symmetric squared error loss function, whereas the intervals estimation is done with three methods: asymptotic and credible confidence intervals. Besides a simulation study, a real-life data set is taken from individuals who live in an environment with several diseases to present the utility of the work. Additionally, a simulation study is constructed to measure and compare different estimation methods.
Structural and Biochemical Basis of Etoposide-Resistant Mutations in Topoisomerase IIα
Authors: Gibson Elizabeth G. , Deweese Joseph E.
Published: June 2022

Etoposide is a widely used anticancer drug that targets type II topoisomerases, including topoisomerase IIα (TOP2A). TOP2A is a nuclear enzyme involved in regulating DNA topology through a double-strand passage mechanism. TOP2A is a homodimeric enzyme with two symmetrical active sites formed by residues from either half of the dimer. Both active sites cleave DNA, forming an enzyme-bound, double-stranded DNA break. Etoposide acts by binding in the active site between the ends of cleaved DNA, preventing the enzyme from ligating the DNA. In the present study, biochemical and structural data are used to examine the mechanism of etoposide resistance found with specific point mutations in TOP2A. Mutations near the active site (D463A, G534R, R487K), along with some outside of the active site (ΔA429 and P716L), are examined. We hypothesize that changes in the coordination of DNA cleavage results from mutations that impact symmetrical relationships in the active site and surrounding regions. In some cases, we report the first data on purified versions of these enzymes. Based upon our results, both local and long-distance factors can impact etoposide action and may indicate interdependent relationships in structure and function.
Transient Axisymmetric Flows of Casson Fluids with Generalized Cattaneo’s Law over a Vertical Cylinder
Authors: Osman Husna Izzati , Vieru Dumitru , Ismail Zulkhibri
Published: June 2022

Unsteady axial symmetric flows of an incompressible and electrically conducting Casson fluid over a vertical cylinder with time-variable temperature under the influence of an external transversely magnetic field are studied. The thermal transport is described by a generalized mathematical model based on the time-fractional differential equation of Cattaneo’s law with the Caputo derivative. In this way, our model is able to highlight the effect of the temperature gradient history on heat transport and fluid motion. The generalized mathematical model of thermal transport can be particularized to obtain the classical Cattaneo’s law and the classical Fourier’s law. The comparison of the three models could offer the optimal model of heat transport. The problem solution has been determined in the general case when cylinder surface temperature is described by a function f(t); therefore, the obtained solutions can be used to study different convective flows over a cylinder. In the particular case of surface temperature varying exponentially in time, it is found that fractional models lead to a small temperature rise according to the Cattaneo model.
Metabolic Resistance in Abamectin-Resistant Bemisia tabaci Mediterranean from Northern China
Authors: Wang Ran , Fang Yong , Che Wunan , Zhang Qinghe , Wang Jinda , Luo Chen
Published: June 2022

Abamectin, produced by the soil-dwelling actinomycete Streptomyces avermitilis, belongs to the macrocyclic lactones class of pesticides, has nematocidal, acaricidal, and insecticidal activity, and is highly effective when used against targeted species. Bemisia tabaci, the tobacco whitefly, is a highly destructive insect to agricultural production worldwide, and various insecticide-resistant strains have been identified in China. Here, we monitored levels of resistance to abamectin in twelve field-collected B. tabaci populations from northern China, and confirmed that, compared with the lab reference strain, six field populations exhibited strong abamectin resistance, while the other six exhibited low-to-medium resistance. Among these, the Xinzheng (XZ) population displayed about a 40-fold increased resistance to abamectin, and experienced significant cross-resistance to chlorpyrifos and imidacloprid. The abamectin resistance of XZ was found to be autosomal and incompletely dominant. Metabolic enzyme and synergism tests were conducted, and two metabolic enzymes, glutathione S-transferase and P450 monooxygenase, were found to be conducive to the field-developed abamectin resistance of the XZ population. The above results provide valuable information that can be used in identifying new pest control strategies and delaying the evolution of resistance to abamectin in field populations of whiteflies.
Associations between Bonus and Lottery COVID-19 Vaccine Incentive Policies and Increases in COVID-19 Vaccination Rates: A Social Epidemiologic Analysis
Authors: Guo Yuqi , Gao Jingjing , Sims Omar T.
Published: June 2022

The objectives of this longitudinal study were to analyze the impact of COVID-19 vaccine incentive policies (e.g., bonuses and lottery entries) on county-level COVID-19 vaccination rates, and to examine the interactive effects between COVID-19 vaccine incentive policies and socioeconomic factors on COVID-19 vaccination rates. Using publicly available data, county-level COVID-19 vaccination rates and socioeconomic data between January 2021 and July 2021 were extracted and analyzed across counties in the United States (US)—an analysis of 19,992 observations over time. Pooled ordinary least squares (OLS) analysis was employed to longitudinally examine associations with COVID-19 vaccination rates, and four random-effects models were developed to analyze interaction effects. Bonus incentive policies were effective in counties with a high per capita income, high levels of education, and a high percentage of racial minorities, but not in counties with high unemployment. Lottery incentive policies were effective in counties with a high percentage of racial minorities, but not in counties with high per capita income, high levels of education, and high unemployment. County-level socioeconomic factors should be considered ahead of implementing incentive policies, versus a blanket approach, to avoid the unintentional misuse of economic resources for futile COVID-19 vaccination outcomes.
Probing the Interior of the Schwarzschild Black Hole Using Congruences: LQG vs. GUP
Authors: Rastgoo Saeed , Das Saurya
Published: June 2022

We review, as well as provide some new results regarding the study of the structure of spacetime and the singularity in the interior of the Schwarzschild black hole in both loop quantum gravity and generalized uncertainty principle approaches, using congruences and their associated expansion scalar and the Raychaudhuri equation. We reaffirm previous results that in loop quantum gravity, in all three major schemes of polymer quantization, the expansion scalar, Raychaudhuri equation and the Kretschmann scalar remain finite everywhere in the interior. In the context of the eneralized uncertainty principle, we show that only two of the four models we study lead to similar results. These two models have the property that their algebra is modified by configuration variables rather than the momenta.
An Exploratory Study of Crime: Examining Lived Experiences of Crime through Socioeconomic, Demographic, and Physical Characteristics
Authors: Onyeneke Christopher Chimaobi , Karam Aly H.
Published: June 2022

Debates in urban social research indicate that one of the most significant problems facing cities of the global south is the dilemma of crime. This study explores the research question: what is the level of influence of economic deprivation and residential mobility weights on criminal activities within vulnerable neighborhoods in urban centres? This research focuses on the urban social structural theory of social disorganization, to investigate how socioeconomic, demographic, and physical characteristics affect criminal behaviour. The study adopted a qualitative research approach that is cross-sectional. With the use of volunteer self-selection sampling techniques, in-depth interviews were conducted with heads of households via a semi-structured interview guide. The data were analyzed using thematic analysis. The study found that sociological factors such as economic deprivation and socioeconomic inequality lead to the gradual integration of delinquency in cities. The findings of this research build on the existing theory of social disorganization. To ensure safety, residents’ economic status must be standardized by supporting the provision of more regulated informal sector opportunities and activities for active engagement in supervising and controlling youth behaviour.
Shiftless, a Critical Piece of the Innate Immune Response to Viral Infection
Authors: Rodriguez William , Muller Mandy
Published: June 2022

Since its initial characterization in 2016, the interferon stimulated gene Shiftless (SHFL) has proven to be a critical piece of the innate immune response to viral infection. SHFL expression stringently restricts the replication of multiple DNA, RNA, and retroviruses with an extraordinary diversity of mechanisms that differ from one virus to the next. These inhibitory strategies include the negative regulation of viral RNA stability, translation, and even the manipulation of RNA granule formation during viral infection. Even more surprisingly, SHFL is the first human protein found to directly inhibit the activity of the -1 programmed ribosomal frameshift, a translation recoding strategy utilized across nearly all domains of life and several human viruses. Recent literature has shown that SHFL expression also significantly impacts viral pathogenesis in mouse models, highlighting its in vivo efficacy. To help reconcile the many mechanisms by which SHFL restricts viral replication, we provide here a comprehensive review of this complex ISG, its influence over viral RNA fate, and the implications of its functions on the virus-host arms race for control of the cell.
Nucleic Acid Preservation Card Surveillance Is Effective for Monitoring Arbovirus Transmission on Crocodile Farms and Provides a One Health Benefit to Northern Australia
Authors: Kurucz Nina , McMahon Jamie Lee , Warchot Allan , Hewitson Glen , Barcelon Jean , Moore Frederick , Moran Jasmin , Harrison Jessica J. , Colmant Agathe M. G. , Staunton Kyran M. , Ritchie Scott A. , Townsend Michael , Steiger Dagmar Meyer , Hall Roy A. , Isberg Sally R. , Hall-Mendelin Sonja
Published: June 2022

The Kunjin strain of West Nile virus (WNVKUN) is a mosquito-transmitted flavivirus that can infect farmed saltwater crocodiles in Australia and cause skin lesions that devalue the hides of harvested animals. We implemented a surveillance system using honey-baited nucleic acid preservation cards to monitor WNVKUN and another endemic flavivirus pathogen, Murray Valley encephalitis virus (MVEV), on crocodile farms in northern Australia. The traps were set between February 2018 and July 2020 on three crocodile farms in Darwin (Northern Territory) and one in Cairns (North Queensland) at fortnightly intervals with reduced trapping during the winter months. WNVKUN RNA was detected on all three crocodile farms near Darwin, predominantly between March and May of each year. Two of the NT crocodile farms also yielded the detection of MVE viral RNA sporadically spread between April and November in 2018 and 2020. In contrast, no viral RNA was detected on crocodile farms in Cairns during the entire trapping period. The detection of WNVKUN and MVEV transmission by FTATM cards on farms in the Northern Territory generally correlated with the detection of their transmission to sentinel chicken flocks in nearby localities around Darwin as part of a separate public health surveillance program. While no isolates of WNVKUN or MVEV were obtained from mosquitoes collected on Darwin crocodile farms immediately following the FTATM card detections, we did isolate another flavivirus, Kokobera virus (KOKV), from Culex annulirostris mosquitoes. Our studies support the use of the FTATM card system as a sensitive and accurate method to monitor the transmission of WNVKUN and other arboviruses on crocodile farms to enable the timely implementation of mosquito control measures. Our detection of MVEV transmission and isolation of KOKV from mosquitoes also warrants further investigation of their potential role in causing diseases in crocodiles and highlights a “One Health” issue concerning arbovirus transmission to crocodile farm workers. In this context, the introduction of FTATM cards onto crocodile farms appears to provide an additional surveillance tool to detect arbovirus transmission in the Darwin region, allowing for a more timely intervention of vector control by relevant authorities.
Development of a Monoclonal Antibody to Pig CD69 Reveals Early Activation of T Cells in Pig after PRRSV and ASFV Infection
Authors: Tian Yunfei , Hao Yuxin , Dong Maoli , Li Shuai , Wang Dongyue , Jiang Fei , Wang Qingqing , Hao Xiaoli , Yang Yi , Chen Nanhua , Zhu Jianzhong , Guo Junqing , Wu Jiajun , Shang Shaobin , Zhou Jiyong
Published: June 2022

The CD69 molecule, as an early activation marker of lymphocytes, is often used to assess the activation of cellular immunity. However, for pigs, an anti-pig CD69 antibody is not yet available for this purpose after infection or vaccination. In this study, a monoclonal antibody (mAb) against pig CD69 was produced by peptide immunization and hybridoma technique. One mAb (5F12) showed good reactivity with pig CD69 that was expressed in transfected-HEK-293T cells and on mitogen-activated porcine peripheral blood mononuclear cells (PBMCs) by indirect immunofluorescence assay and flow cytometry. This mAb did not cross-react with activated lymphocytes from mouse, bovine, and chicken. Epitope mapping showed that the epitope recognized by this mAb was located at amino acid residues 147–161 of pig CD69. By conjugating with fluorochrome, this mAb was used to detect the early activation of lymphocytes in PRRSV- and ASFV-infected pigs by flow cytometry. The results showed that PRRSV infection induced the dominant activation of CD4 T cells in mediastinal lymph nodes and CD8 T cells in the spleen at 14 days post-infection, in terms of CD69 expression. In an experiment on ASFV infection, we found that ASFV infection resulted in the early activation of NK cells, B cells, and distinct T cell subsets with variable magnitude in PBMCs, spleen, and submandibular lymph nodes. Our study revealed an early event of lymphocyte and T cell activation after PRRSV and ASFV infections and provides an important immunological tool for the in-depth analysis of cellular immune response in pigs after infection or vaccination.
Association of Increased Programmed Death Ligand 1 Expression and Regulatory T Cells Infiltration with Higher Hepatocellular Carcinoma Recurrence in Patients with Hepatitis B Virus Pre-S2 Mutant after Curative Surgical Resection
Authors: Jeng Long-Bin , Li Tsai-Chung , Hsu Shih-Chao , Teng Chiao-Fang
Published: June 2022

Although surgical resection is available as a potentially curative therapy for hepatocellular carcinoma (HCC), high recurrence of HCC after surgery remains a serious obstacle for long-term patient survival. Therefore, the discovery of valuable prognostic biomarkers for HCC recurrence is urgently needed. Pre-S2 mutant is a mutant form of hepatitis B virus (HBV) large surface protein which is expressed from the HBV surface gene harboring deletion mutations spanning the pre-S2 gene segment. Pre-S2 mutant-positive HCC patients have been regarded as a high-risk population of HCC recurrence after resection surgery and display increased immune checkpoint programmed death ligand 1 (PD-L1) expression and pro-tumor regulatory T cells (Tregs) infiltration in tumor tissues. In this study, the association of higher levels of PD-L1 expression and Tregs infiltration in tumor tissues with post-operative HCC recurrence in pre-S2 mutant-positive HCC patients was evaluated. We found that patients with pre-S2 mutant in combination with higher levels of PD-L1 expression and Tregs infiltration in tumor tissues were independently associated with a higher risk of HCC recurrence (hazard ratio, 4.109; p value = 0.0011) and poorer recurrence-free survival (median, 8.2 versus 18.0 months; p value = 0.0004) than those of patients with either one or two of these three biomarkers. Furthermore, a combination of pre-S2 mutant, intra-tumoral PD-L1 expression, and tumor-infiltrating Tregs exhibited superior performance in identifying patients at a higher risk of HCC recurrence (area under the receiver operating characteristic curve, 0.8400). Collectively, this study suggests that higher levels of PD-L1 expression and Tregs infiltration in tumor tissues predicted a higher risk of HCC recurrence in pre-S2 mutant-positive HCC patients after curative surgical resection.
The Importance of Secretor-Status in Norovirus Infection Following Allogeneic Hematopoietic Stem Cell Transplantation
Authors: Swartling Lisa , Sparrelid Elda , Ljungman Per , Boriskina Ksenia , Valentini Davide , Svensson Lennart , Nordgren Johan
Published: June 2022

Background. Human secretor-status is a strong susceptibility factor for norovirus infection in immunocompetent people. The predominant norovirus genotype GII.4 almost exclusively infects secretors and is also associated with more severe symptoms. However, it is not known to what extent this also applies to immunocompromised individuals. Our objective was to determine the importance of secretor-status and norovirus genotype for the susceptibility and/or the clinical course of norovirus infection in allogeneic hematopoietic stem cell transplant (HCT) patients. Methods: This was a retrospective study of 89 HCT patients diagnosed with norovirus infection. Secretor-status and norovirus genotype were determined using stored extracted DNA or blood (n = 89) and fecal samples (n = 22), respectively. Results: Seven of eighty-nine (8%) of the patients were secretor-negative, a small proportion compared to the expected rate of at least 20% non-secretors in the general Swedish population. Among the genotyped samples, norovirus genotype GII.4 was predominant (n = 12) and only detected in secretor-positive individuals. Patients with norovirus GII.4 had a median symptom duration of 36 (3–681) days compared to 15 (1–94) days in patients infected with other norovirus genotypes (n = 10, p = 0.1). Conclusions: The results suggest that secretor-status affects the susceptibility to norovirus infection even when the immune system is severely compromised. The norovirus genotype may also be a risk factor for chronic norovirus symptoms in immunocompromised patients.
Point-of-Care Tests for Rapid Detection of Porcine Epidemic Diarrhea Virus: A Systematic Review and Meta-Analysis
Authors: Li Renfeng , Tian Xiangqin , Pang Junzeng , Li Linyue , Yuan Jiakang , Tian Zhuangzhuang , Wang Ziliang
Published: June 2022

The timely and accurate diagnosis of porcine epidemic diarrhea virus (PEDV) infection is crucial to reduce the risk of viral transmission. Therefore, the objective of this review was to evaluate the overall diagnostic accuracy of rapid point-of-care tests (POCTs) for PEDV. Studies published before 7 January 2022 were identified by searching PubMed, EMBASE, Springer Link, and Web of Science databases, using subject headings or keywords related to point of care and rapid test diagnostic for PEDV and PED. Two investigators independently extracted data, rated risk of bias, and assessed the quality using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. The bivariate model and the hierarchical summary receiver operating characteristic (HSROC) model were used for performing the meta-analysis. Threshold effect, subgroup analysis, and meta-regression were applied to explore heterogeneity. Of the 2908 records identified, 24 eligible studies involving 3264 specimens were enrolled in the meta-analysis, including 11 studies on evaluation of lateral flow immunochromatography assay (ICA)-based, and 13 on nucleic acid isothermal amplification (NAIA)-based POCTs. The overall pooled sensitivity, specificity and diagnostic odds ratio (DOR) were 0.95 (95% CI: 0.92–0.97), 0.96 (95% CI 0.88–0.99) and 480 (95% CI 111–2074), respectively; for ICA-based POCTs and the corresponding values for NAIA-based, POCTs were 0.97 (95% CI 0.94–0.99), 0.98 (95% CI 0.91–0.99) and 1517 (95% CI 290–7943), respectively. The two tests showed highly comparable and satisfactory diagnostic performance in clinical utility. These results support current recommendations for the use of rapid POC tests when PEDV is suspected.
Serotype I and II Feline Coronavirus Replication and Gene Expression Patterns of Feline Cells—Building a Better Understanding of Serotype I FIPV Biology
Authors: Cook Sarah , Castillo Diego , Williams Sonyia , Haake Christine , Murphy Brian
Published: June 2022

Feline infectious peritonitis (FIP) is a disease of domestic cats caused by the genetic variant of the feline coronavirus (FCoV) and feline infectious peritonitis virus (FIPV), currently grouped into two serotypes, I and II. Although serotype I FIPV is more prevalent in cats with FIP, serotype II has been more extensively studied in vitro due to the relative ease in propagating this viral serotype in culture systems. As a result, more is known about serotype II FIPV than the more biologically prevalent serotype I. The primary cell receptor for serotype II has been determined, while it remains unknown for serotype I. The recent development of a culture-adapted feline cell line that more effectively propagates serotype I FIPV, FCWF-4 CU, derived from FCWF-4 cells available through the ATCC, offers the potential for an improved understanding of serotype I FIPV biology. To learn more about FIPV receptor biology, we determined targeted gene expression patterns in feline cells variably permissive to replication of serotype I or II FIPV. We utilized normal feline tissues to determine the immunohistochemical expression patterns of two known coronavirus receptors, ACE2 and DC-SIGN. Lastly, we compared the global transcriptomes of the two closely related FCWF-4 cell lines and identified viral transcripts with potential importance for the differential replication kinetics of serotype I FIPV.
Genomic Comparisons of Alphacoronaviruses and Betacoronaviruses from Korean Bats
Authors: Lo Van Thi , Yoon Sun Woo , Choi Yong Gun , Jeong Dae Gwin , Kim Hye Kwon
Published: June 2022

Coronaviruses are well known as a diverse family of viruses that affect a wide range of hosts. Since the outbreak of severe acute respiratory syndrome, a variety of bat-associated coronaviruses have been identified in many countries. However, they do not represent all the specific geographic locations of their hosts. In this study, full-length genomes representing newly identified bat coronaviruses in South Korea were obtained using an RNA sequencing approach. The analysis, based on genome structure, conserved replicase domains, spike gene, and nucleocapsid genes revealed that bat Alphacoronaviruses are from three different viral species. Among them, the newly identified B20-97 strain may represent a new putative species, closely related to PEDV. In addition, the newly-identified MERS-related coronavirus exhibited shared genomic nucleotide identities of less than 76.4% with other Merbecoviruses. Recombination analysis and multiple alignments of spike and RBD amino acid sequences suggested that this strain underwent recombination events and could possibly use hDPP4 molecules as its receptor. The bat SARS-related CoV B20-50 is unlikely to be able to use hACE2 as its receptor and lack of an open reading frame in ORF8 gene region. Our results illustrate the diversity of coronaviruses in Korean bats and their evolutionary relationships. The evolution of the bat coronaviruses related ORF8 accessory gene is also discussed.
Effective Infection with Dengue Virus in Experimental Neonate and Adult Mice through the Intranasal Route
Authors: Qiu Minyue , Zhao Lixin , Zhang Junjie , Wang Yalan , Liu Minchi , Hua Dong , Ding Xiaoyan , Zhou Xiaoyang , Zeng Jie , Yan Huacheng , Li Jintao
Published: June 2022

Dengue virus, the causative agent of dengue fever, life-threatening hemorrhagic fever, and shock syndrome, is mainly transmitted to humans through mosquito vectors. It can also be transmitted through atypical routes, including needle stick injury, vertical transmission, blood transfusion, and organ transplantation. In addition, sporadic cases which have no clear infectious causes have raised the respiratory exposure concerns, and the risks remain unclear. Here, we analyze the respiratory infectivity of the dengue virus in BALB/c suckling and adult immunodeficient mice by the intranasal inoculation of dengue virus serotype 2. The infected mice presented with clinical symptoms, including excitement, emaciation, malaise, and death. Viremia was detected for 3 days post inoculation. Histopathological changes were observed in the brain, liver, and spleen. The virus showed evident brain tropism post inoculation and viral loads peaked at 7 days post inoculation. Furthermore, the virus was isolated from the infected mice; the sequence homology between the origin and isolates was 99.99%. Similar results were observed in adult IFN-α/β receptor-deficient mice. Overall, dengue virus can infect suckling mice and adult immune-deficient mice via the nasal route. This study broadens our perception of atypical dengue transmission routes and provides evidence of nasal transmission of dengue virus in the absence of mosquito vectors.
Optimization of a Non-Traditional Vibration Absorber for Vibration Suppression and Energy Harvesting
Authors: Yuan Miao , Jin Youzuo , Liu Kefu , Sadhu Ayan
Published: June 2022

This paper investigates the optimization of a non-traditional vibration absorber for simultaneous vibration suppression and energy harvesting. Unlike a traditional vibration absorber, the non-traditional vibration absorber has its damper connected between the absorber mass and the base. An electromagnetic energy harvester is used as a tunable absorber damper. This non-traditional vibration absorber is attached to a primary system that is subjected to random base excitation. An analytical study is conducted by assuming that the base excitation is white noise. In terms of vibration suppression, the objective of the optimization is to minimize the power dissipated by the primary damper and maximize the power dissipated by the absorber damper. It is found that when the primary system is undamped, the power dissipated by the absorber damper remains a constant that is related to the mass ratio. The higher the mass ratio, the higher the power dissipated. When the primary system is damped, the minimization of the power dissipated by the primary damping is equivalent to the maximization of the power dissipated by the absorber damper. The existence of the optimum solutions depends on both the mass ratio and the primary damping ratio. In terms of energy harvesting, the objective of optimization is to maximize the power harvested by the load resistor. It is found that for a given mass ratio and primary damping ratio, the optimum frequency tuning ratio required to maximize vibration suppression is slightly higher than that required to maximize the harvested power. The trade-off issue between vibration suppression and energy harvesting is investigated. An apparatus is developed to allow frequency tuning and damping tuning. Both the numerical simulation and experimental study with band-limited white noise validate the general trends revealed in the analytical study.
Consolidation Properties of Soil/Modified Bentonite Backfill in Salt Solution
Authors: Fang Aiguo , Yang Yuling , Yang Zhongjun , Hua Sudong , Wang Jinchao , Zhou Feng
Published: June 2022

The consolidation properties of soil-bentonite (SB) backfills containing 20% of the weight of sodium-hexametaphosphate-modified calcium bentonite (SHMP-20CaB) and prepared with 0 mM to 1000 mM calcium chloride (CaCl2) solution were evaluated. The results indicated that both consolidation stress and CaCl2 concentration had significant effects on the consolidation behaviors of the SHMP-20CaB backfill. In general, an increase in consolidation stress resulted in a decrease in the void ratio (e) and in the coefficient of volume change (mv), alongside an increase in the coefficient of consolidation (cv). The increased CaCl2 concentration yielded a dropped void ratio, and a nonlinear decreased compression index (Cc) and rebound index (Cs), respectively, from 0.18 to 0.13 and from 0.022 to 0.010, and a nonlinear increase cv. A threshold CaCl2 concentration of 100 mM was observed at the inflection points of the Cc, Cs, and cv. In contrast, the mv was insensitive to the CaCl2 solutions. The deterioration in e, Cc, and Cs and the increase in cv were the result of a compressed diffuse double layer of the bentonite by the CaCl2 solution, which thus exerted certain negative effects on the consolidation behaviors of the SHMP-20CaB backfill.
Combining Fish Passage and Sediment Bypassing: A Conceptual Solution for Increased Sustainability of Dams and Reservoirs
Authors: Foldvik Anders , Silva Ana T. , Albayrak Ismail , Schwarzwälder Kordula , Boes Robert M. , Ruther Nils
Published: June 2022

Sedimentation is one of the main eco-morphological and technological challenges associated with reservoirs. Sedimentation not only reduces the functional capacity of a reservoir by filling it, but also changes downstream sediment dynamics and habitat availability for the aquatic biota. Additionally, dams hinder free bi-directional fish passage, emerging as a major threat to species of migratory fish. In the past decades, mitigation measures aimed at reducing such environmental and technological impacts have been developed. Sediment bypass tunnels (SBTs) have been shown to successfully help prevent reservoir sedimentation, whereas fish passages have been found to be potential solutions to facilitate bi-directional passage of fish. However, the construction of such structures, in particular of SBT, can be extremely costly. The development of design solutions that can function both for downstream sediment transport and up- and downstream fish passage should be considered as they can mitigate ecological deficiencies of reservoir operations while accounting for economic feasibility. Possibilities and challenges of combining SBT and fish passage were explored by bringing together a team of interdisciplinary specialists on hydraulics, sediment transport and continuity, bypassing, hydraulic structures, hydropower engineering, aquatic biology, and fish passage in a two-day workshop. Here, we present potential solutions identified during the workshop for integrating SBT and fish passage.
Travelling Plastics: Exploring River Cruise Companies’ Practices and Policies for the Environmental Protection of the Rhine
Authors: van Klink Demi , Wiering Mark , van Eerd Marjolein , Schoor Margriet
Published: June 2022

Since 2013, romantic Rhine cruises gained immense popularity in Europe. However, these tourism activities also involve the generation of large amounts of waste. As rivers contribute significantly to the plastic waste influx in the marine environment, it is essential that river cruise companies cope with plastics in an environmentally-safe way. In this contribution, we try to overcome knowledge gaps regarding both the plastic practices of river cruise companies and the policies on cruise tourism and environmental pollution. We adopt a multiple-case study approach and use the Social Practice Theory to analyse the companies’ practices and challenges. Furthermore, we combine this with the analytical approaches of the Policy Arrangements and Synoptic Governance to explore the policies for environmental protection and tourism. The results show that, overall, river cruise companies have an eco-friendly approach to plastic waste management. However, dealing with plastics in the freshwater environment is not sufficiently rooted in the above policies: river cruise companies face important omissions in policies and facilities, resulting in plastic emissions in the river. Following the results, we formulate recommendations to support sustainable waste management routines onboard and to improve waste reception facilities onshore to protect the aquatic environment.
Modeling of Sediment Transportation in Ichkeul Lake for the Estimation of the Influence of the Constructions of the Reservoirs in the Upper Streams
Authors: Irie Mitsuteru , Kotegawa Hirotoshi , Kawachi Atsushi , Ouni Hajel , Tarhouni Jamila
Published: June 2022

Rich ecosystems such as estuaries and brackish lakes are vulnerable to the effects of human activities and are prone to environmental changes. In particular, the salt environment, which is the backbone of the environment, might be affected not only by direct modifications such as dredging but also in ways that were not initially envisioned. Ichkeul Lake, located in the northern part of Tunisia, is a shallow brackish lake registered as a UNESCO World Natural Heritage Site. The construction of reservoirs upstream of the inflowing river in the 1980s reduced the amount of freshwater inflow. That only had been thought to be the cause of the increase in salinity in Ishkeul Lake. On the other hand, the sedimentation in the reservoirs upstream was remarkable, and the supply of sediment from the reservoirs upstream to the Ichkeul Lake was stopped. Changes in sediment outflow may have reduced lakebed altitude and enhanced seawater intrusion. However, the environmental protection measures for the lake so far have focused only on improving the water budget and have not been quantitatively evaluated for sediment transportation. In this study, we first estimated the water budget of the lake. Then the re-suspension by wind disturbance in the lake was estimated from the correlation with the wind speed based on laboratory experiments and field measurements. The outflow of the sediment estimated with these two models was compared with the sediment volume trapped in the upstream reservoirs that would have flowed into the lake if there had been no construction of the dams. Based on this, we evaluated whether the lake is currently erosive or cumulative. As a result, the estimated annual outflow of sediment to the sea was 4300 tons/year. It was estimated that the construction of the reservoirs upstream changed the trend of lakebed height from accumulation to erosion.
The Effect of Spatial Input Data Quality on the Performance of the SWAT Model
Authors: Kmoch Alexander , Moges Desalew Meseret , Sepehrar Mahdiyeh , Narasimhan Balaji , Uuemaa Evelyn
Published: June 2022

Soil and land use information are important inputs for physically-based hydrological modeling such as SWAT. Although fine resolution local or regional data are often preferred for modeling, it is not always reliable that these data can lead to better model performance. In this study, we investigate the effect of input data on the sensitivity and uncertainty of the SWAT model in the Porijõgi catchment in Estonia. We created four model setups using global/regional level data (HWSD soil and CORINE) and local high-resolution spatial data, including the Estonian high-resolution EstSoil-EH soil dataset and the Estonian Topographic Database (ETAK). We employed statistical criteria to assess SWAT model performance for monthly simulated stream flows from 2007 to 2019. The results illustrated that models with high-resolution local soil data performed lower than models with global soil data, but in contrast, in the case of land use datasets, the local high-resolution ETAK dataset improved performance over the CORINE data.
Pore-Scale Wetting Process of Capillary-Driven Flow in Unsaturated Porous Media under Micro- and Earth-Gravities
Authors: Maruo Yuichi , Sato Naoto , Nogawa Kento , Aoki Shinsuke , Noborio Kosuke
Published: June 2022

Microgravity hinders capillary-driven water flow in unsaturated porous media. Previous studies proposed pore-scale phenomena such as “air entrapment”, “particle separation”, and “interruption on widening void space” to explain gravity-dependent capillary-driven flows. Our objectives were: (1) to measure the water flux densities of the pore-scale capillary-driven flow in micro- and Earth-gravities and (2) to reveal that what makes water flow slower under microgravity than under 1 G. We found that average macroscopic water flux densities had no significant difference under micro- and Earth-gravities (p = 0.30). We did not observe “air entrapment” in the pore spaces of porous media. “Widening on a single particle” and “capillary widening” disturbed capillary-driven flow; however, “widening on a single particle” had no significant gravity dependency. “Capillary widening” may be independent of gravity, since it was observed both under microgravity and under 1 G. Water flux densities in unsaturated porous media may have gravity dependency induced by “particle separation” only when porosity is large enough to allow particles to move.
In Situ Remediation of Arsenic-Contaminated Groundwater by Injecting an Iron Oxide Nanoparticle-Based Adsorption Barrier
Authors: Mohammadian Sadjad , Tabani Hadi , Boosalik Zahra , Asadi Rad Amir , Krok Beate , Fritzsche Andreas , Khodaei Kamal , Meckenstock Rainer U.
Published: June 2022

Arsenic contamination of groundwater occurs due to both geogenic and anthropogenic processes. Conventional arsenic remediation techniques require extraction of groundwater into pump-and-treat systems, which are expensive and require long operational times. Hence, there is a need for cost-effective remediation. In this study, we assessed and validated the in situ remediation of arsenic contamination in groundwater resources using permeable reactive barriers (PRBs) made of injectable, colloidal iron oxide nanoparticles in the laboratory and in field-scale pilot tests. Sand-packed, flow-through column studies were used in order to assess the sorption behavior of the iron oxide nanoparticles using field materials (sand, groundwater) in the laboratory. The breakthrough curves were analyzed using a reactive transport model considering linear and nonlinear adsorption isotherms and were fitted best with a chemical nonequilibrium consideration. The results were used to design a pilot-scale field test. The injected 28 m3 of nanoparticles (ca. 280 kg dry weight of iron oxide) were successfully delivered to the aquifer via an injection well. No mobile iron was detected downstream, confirming that a stable in situ barrier was formed that did not move with the groundwater flow. Arsenic concentrations in groundwater were reduced to the aimed 50% of the background value, despite the relatively short contact time between arsenic and the iron oxide in the barrier, due to the high flow velocity of 1.21 m/day. We compared the results of the laboratory and field tests and concluded that the single-parameter models based on retardation factor and/or adsorption capacity fail to predict the longevity of the barrier and the evolution of arsenic breakthrough with time, most likely because they do not consider the chemical nonequilibrium effects. Therefore, we propose that upscaling the laboratory findings to field design must be carried out with care and be coupled with detailed reactive transport models.
Climate Drivers Contribute in Vegetation Greening Stalls of Arid Xinjiang, China: An Atmospheric Water Drying Effect
Authors: Li Moyan , Guan Jingyun , Zheng Jianghua
Published: June 2022

Xinjiang, an arid region of China, has experienced a substantial warming–wetting trend over the past five decades. However, climate change has affected vegetation growth/greening in arid Central Asia in unexpected ways due to complex ecological effects. We found a significant greening trend (consistent increase in the normalized difference vegetation index or NDVI) from 1982 to 1996, during the growing season; however, the NDVI consequently decreased and plateaued from 1997 to 2015, especially in naturally vegetated regions. Atmospheric vapor pressure deficit (VPD) is a critical driver of vegetation growth, is a direct measure of atmospheric aridity, and has increased sharply in recent decades. A partial correlation analysis indicated a significant relationship between growing season NDVI and VPD from 1997 to 2015. This implies that decreased VPD corresponds to increasing NDVI, and increasing VPD corresponds to a decrease and plateauing in the NDVI trend. Using the partial derivative equation method, our results suggest that the trend in growing season NDVI was affected primarily by increasing VPD (contributing 87.57%) from 1997 to 2015, especially in the grassland and desert biomes. Rising temperatures lead to a greater VPD, resulting in exacerbated evaporative water loss. Soil drought and atmospheric aridity limit plant stomatal conductance and could effectively lead to a decrease in the greening trend and increased vegetation mortality in arid Xinjiang. Our results emphasize the importance of VPD as a limiting factor of greening trends in arid regions. The influence of VPD on vegetation growth should be considered when evaluating arid ecosystem functioning under global warming.
Groundwater Quality Affected by the Pyrite Ash Waste and Fertilizers in Valea Calugareasca, Romania
Authors: Vasilache Nicoleta , Diacu Elena , Modrogan Cristina , Chiriac Florentina Laura , Paun Iuliana Claudia , Tenea Anda Gabriela , Pirvu Florinela , Vasile Gabriela Geanina
Published: June 2022

The aim of the study was to assess the groundwater quality in a rural area affected by the abandoned pyrite ash waste dumps. The abundance of major ions in groundwater depends largely on the nature of the rocks, climatic conditions, and mobility. To evaluate geochemical processes, 30 groundwater samples collected from Valea Calugareasca, Prahova County, Romania, were analyzed for the major anions (NO3−, SO42−, Cl−, HCO3−, and F−) and cations (Ca2+, Mg2+, Na+, and K+), which are naturally highly variable due to climatic and geographical location conditions. Ca2+, Na+, Mg2+, and K+ varied between 118 and 275 mg/L, 32 and 160 mg/L, 12.2 and 78.4 mg/L, and 0.21 and 4.48 mg/L, respectively. NO3− levels exceeding the World Health Organization (WHO) limit of 50 mg/L were identified in 17% of the groundwater samples, mainly as result of fertilizers applied to agricultural activities. The hydrogeochemical study identified dolomite dissolution and halite precipitation as natural sources of ions as well as the presence of pyrite as a source of SO42− ions in 60% of the samples. The sulfate content varied between 125 and 262 mg/L. Bicarbonate and chloride concentrations varied between 202 and 530 mg/L and 21 and 212 mg/L. The saturation index indicates the contribution of Ca2+ ions in the groundwater samples came from some processes of dissolving rocks such as aragonites (values between 1.27 and 2.69) and calcites (values between 1.43 and 2.82). Negative halite values indicated that salt accumulation results from precipitation processes. Only 10% of the analyzed groundwater samples were suitable for human consumption, the samples being situated on the hill, far away from the pyrite ash waste dumps and agricultural land.
Direct and Activated Chlorine Dioxide Oxidation for Micropollutant Abatement: A Review on Kinetics, Reactive Sites, and Degradation Pathway
Authors: Ma Xiaohong , Chen Huan , Chen Ruihuan , Hu Xiaojun
Published: June 2022

Recently, ClO2-based oxidation has attracted increasing attention to micropollutant abatement, due to high oxidation potential, low disinfection byproduct (DBPs) formation, and easy technical implementation. However, the kinetics, reactive sites, activation methods, and degradation pathways involved are not fully understood. Therefore, we reviewed current literature on ClO2-based oxidation in micropollutant abatement. In direct ClO2 oxidation, the reactions of micropollutants with ClO2 followed second-order reaction kinetics (kapp = 10−3–106 M−1 s−1 at neutral pH). The kapp depends significantly on the molecular structures of the micropollutant and solution pH. The reactive sites of micropollutants start with certain functional groups with the highest electron densities including piperazine, sulfonyl amido, amino, aniline, pyrazolone, phenol groups, urea group, etc. The one-electron transfer was the dominant micropollutant degradation pathway, followed by indirect oxidation by superoxide anion radical (O2•−) or hydroxyl radical (•OH). In UV-activated ClO2 oxidation, the reactions of micropollutants followed the pseudo-first-order reaction kinetics with the rates of 1.3 × 10−4–12.9 s−1 at pH 7.0. Their degradation pathways include direct ClO2 oxidation, direct UV photolysis, ozonation, •OH-involved reaction, and reactive chlorine species (RCS)-involved reaction. Finally, we identified the research gaps and provided recommendations for further research. Therefore, this review gives a critical evaluation of ClO2-based oxidation in micropollutant abatement, and provides recommendations for further research.