bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of a Nutritional Mobile Application for Management of Hyperphosphatemia in Patients on Hemodialysis: A Multicenter Open-Label Randomized Clinical Trial
Authors: Teong Lee-Fang , Khor Ban-Hock , Ng Hi-Ming , Sahathevan Sharmela , Purba Kristo Radion , Narayanan Sreelakshmi Sankara , Gafor Abdul Halim Abdul , Goh Bak-Leong , Bee Boon-Cheak , Yahya Rosnawati , Bavanandan Sunita , Wahab Zaimi , Mazlan Sadanah Aqashiah , Chinna Karuthan , Morad Zaki , Daud Zulfitri Azuan Mat , Karupaiah Tilakavati
Published: June 2022

This study aims to determine the effectiveness of a phosphate mobile app (PMA), MyKidneyDiet-Phosphate Tracker ©2019, on hemodialysis (HD) patients with hyperphosphatemia. A multicenter, open-label, randomized controlled trial design allowed randomization of patients with hyperphosphatemia to either the usual care group (UG; receiving a single dietitian-led session with an education booklet) or the PMA group (PG). Thirty-three patients in each intervention group completed the 12-week study. Post-intervention, serum phosphorus levels were reduced in both groups (PG: −0.25 ± 0.42 mmol/L, p = 0.001; UG: −0.23 ± 0.33 mmol/L, p < 0.001) without any treatment difference (p > 0.05). Patients in both groups increased their phosphate knowledge (PG: 2.18 ± 3.40, p = 0.001; UG: 2.50 ± 4.50, p = 0.003), without any treatment difference (p > 0.05). Dietary phosphorus intake of both groups was reduced (PG: −188.1 ± 161.3 mg/d, p < 0.001; UG: −266.0 ± 193.3 mg/d, p < 0.001), without any treatment difference (p > 0.05). The serum calcium levels of patients in the UG group increased significantly (0.09 ± 0.20 mmol/L, p = 0.013) but not for the PG group (−0.03 ± 0.13 mmol/L, p = 0.386), and the treatment difference was significant (p = 0.007). As per phosphate binder adherence, both groups reported a significant increase in Morisky Medication Adherence Scale scores (PG: 1.1 ± 1.2, p < 0.001; UGa: 0.8 ± 1.5, p = 0.007), without any treatment difference (p > 0.05). HD patients with hyperphosphatemia using the PMA achieved reductions in serum phosphorus levels and dietary phosphorus intakes along with improved phosphate knowledge and phosphate binder adherence that were not significantly different from a one-off dietitian intervention. However, binder dose adjustment with meal phosphate content facilitated by the PMA allowed stability of corrected calcium levels, which was not attained by UC patients whose binder dose was fixed.
No-Code Platform-Based Deep-Learning Models for Prediction of Colorectal Polyp Histology from White-Light Endoscopy Images: Development and Performance Verification
Authors: Gong Eun Jeong , Bang Chang Seok , Lee Jae Jun , Seo Seung In , Yang Young Joo , Baik Gwang Ho , Kim Jong Wook
Published: June 2022

Background: The authors previously developed deep-learning models for the prediction of colorectal polyp histology (advanced colorectal cancer, early cancer/high-grade dysplasia, tubular adenoma with or without low-grade dysplasia, or non-neoplasm) from endoscopic images. While the model achieved 67.3% internal-test accuracy and 79.2% external-test accuracy, model development was labour-intensive and required specialised programming expertise. Moreover, the 240-image external-test dataset included only three advanced and eight early cancers, so it was difficult to generalise model performance. These limitations may be mitigated by deep-learning models developed using no-code platforms. Objective: To establish no-code platform-based deep-learning models for the prediction of colorectal polyp histology from white-light endoscopy images and compare their diagnostic performance with traditional models. Methods: The same 3828 endoscopic images used to establish previous models were used to establish new models based on no-code platforms Neuro-T, VLAD, and Create ML-Image Classifier. A prospective multicentre validation study was then conducted using 3818 novel images. The primary outcome was the accuracy of four-category prediction. Results: The model established using Neuro-T achieved the highest internal-test accuracy (75.3%, 95% confidence interval: 71.0–79.6%) and external-test accuracy (80.2%, 76.9–83.5%) but required the longest training time. In contrast, the model established using Create ML-Image Classifier required only 3 min for training and still achieved 72.7% (70.8–74.6%) external-test accuracy. Attention map analysis revealed that the imaging features used by the no-code deep-learning models were similar to those used by endoscopists during visual inspection. Conclusion: No-code deep-learning tools allow for the rapid development of models with high accuracy for predicting colorectal polyp histology.
Economic Stimulus and Financial Instability: Recent Case of the U.S. Household
Authors: Choi Youngna
Published: June 2022

The effectiveness of government policies and economic stimuli during the 2007 financial crisis and the COVID-19 pandemic are compared in this study. While the 2007 financial crisis started in the real estate market and spread through the contagion effect to other sectors, the pandemic halted the all sectors of the global economy simultaneously. In the United States, where the social safety net is not as strong as other advanced economies, the unemployment rate skyrocketed and many families lost income. The federal government countered with various relief packages, which have been, unlike the rounds of quantitative easing prevalent after the 2007 financial crisis, direct payments to households and businesses. The Agent Instability Indicator and default elasticity coefficient are used to quantitatively assess the financial instability and default risk of subgroups of United States households classified by percentile of income and net worth. It turns out that the financial instability level of the United States household during the pandemic has not been as high as that during the 2007 crisis and the Great Recession. It is concluded that the direct handout of cash—so called helicopter money—is more effective at preventing financial collapse and stabilizing the economy than quantitative easing through asset purchase.
Behavioral Changes of Brown Bears (Ursus arctos) during COVID-19 Zoo Closures and Further Reopening to the Public
Authors: Podturkin Aleksei A.
Published: June 2022

Visitor effect studies have been of keen interest for decades, but there have been only anecdotal opportunities to investigate the impact of the prolonged absence of visitors on animal welfare in zoos. In some zoos, bears are actively involved in animal–visitors interaction through begging, which gives them some degree of control over gaining food rewards throughout the day when visitors are present. Prolonged visitor absence may, therefore, represent a loss of control and have a negative impact on the bears’ welfare. In this study, we investigate the behavior of four brown bears (Ursus arctos) in three zoos to see how the animals’ behavior changed depending on the presence and absence of the public during zoo closures in 2020 related to the COVID-19 pandemic. The bears’ behavior was assessed using activity budget analysis and novel object tests. The results showed that the bears behavior varied between facilities and that there was no effect of visitor presence for the individuals who had access to indoor holding space. The results of the study are discussed in terms of choice and control and their impact on the wellbeing of bears in zoos.
The Boar War: Five Hot Factors Unleashing Boar Expansion and Related Emergency
Authors: Fulgione Domenico , Buglione Maria
Published: June 2022

The recent and ever-growing problem of boar (Sus scrofa forms including wild boar, hybrid and feral pig) expansion is a very complex issue in wildlife management. The damages caused to biodiversity and the economies are addressed in different ways by the various countries, but research is needed to shed light on the causal factors of this emergency before defining a useful collaborative management policy. In this review, we screened more than 280 references published between 1975–2022, identifying and dealing with five hot factors (climate change, human induced habitat modifications, predator regulation on the prey, hybridization with domestic forms, and transfaunation) that could account for the boar expansion and its niche invasion. We also discuss some issues arising from this boar emergency, such as epizootic and zoonotic diseases or the depression of biodiversity. Finally, we provide new insights for the research and the development of management policies.
Evaluation of Medical Carrying Capacity for Megacities from a Traffic Analysis Zone View: A Case Study in Shenzhen, China
Authors: Wu Jiansheng , Yi Tengyun , Wang Han , Wang Hongliang , Fu Jiayi , Zhao Yuhao
Published: June 2022

Sustainable Development Goals propose to build inclusive, safe, resilient, and sustainable cities and human settlements, which requires us to scientifically evaluate the carrying capacity of current urban public service facilities, but there is still a lack of in-depth exploration of urban public medical service facilities. Therefore, this paper, within the mobile phone signaling data, improved the potential model and carrying capacity evaluation model of public medical facilities, explored the spatial pattern distribution of public medical resources in Shenzhen, and analyzed the current situation of carrying capacity of public medical resources. The study showed that: (1) the overall spatial distribution of public medical resources in Shenzhen is uneven, showing a pattern of multicenter aggregation and multilevel development; (2) the service potential of public medical facilities has obvious spatial variations, with Futian District, Dapeng New District, and Nanshan District showing more obvious high-gravitational-value aggregation centers; (3) medical facilities in Shenzhen are never empty, but the problems of medical underloading and overloading are severe, and spatial allocation and utilization efficiency need to be further optimized. The research results can provide a scientific basis for the research on the allocation and sustainable construction of medical resources in megacities.
National Fitness Evaluation of Urban Parks in the National Ecological Garden City: A Case Study in Baoji, China
Authors: Tian Yunxi , Ning Haidong , Ren Hongqian , Liu Jianjun , Wang Kai , Hong Bo
Published: June 2022

Urban parks are important places for residents to engage in physical activity (PA). Properly designed fitness facilities play a positive role in the PA level of park users. We conducted a quantitative evaluation of urban park systems based on the revised Chinese version of ParkScore (RCPS) from the perspective of national fitness. Baoji, one of the first National Ecological Garden Cities (NEGCs), was selected as a case study. We analyzed 19 parks and found that comprehensive parks and sports parks obtained high evaluation scores. The area of fitness facilities in Baoji urban parks was low, with an average of 1.85 hm2 per park. Professional sports venues and multifunctional sports venues each accounted for about one-third and children’s activity venues for about a quarter. There were many national fitness stations, but they covered a small area. Only 16% of parks had fitness trails, which was the least represented type of fitness facility. About 40% of the parks had children’s activity venues, with a 1:2 ratio of PA venue to amusement area. The area of free open venues accounted for only 0.1% of the total area of the parks. The number of parks per capita was about 52% of the overall NEGCs, accessibility of 500 m was 34%, and of 1000 m was about 54%. Overall, we found that the supply of Baoji urban parks was insufficient. These results directly reflect differences among fitness facilities in urban parks and can help form a quantitative basis for the optimization of urban park systems and advance the national fitness plan and promote public health.
Impacts of Ecological Migration on Land Use and Vegetation Restoration in Arid Zones
Authors: Zhang Wei , Zhou Liang , Zhang Yan , Chen Zhijie , Hu Fengning
Published: June 2022

Poverty and disasters are globally prevalent in ecologically fragile areas. Ecological migration is regarded as an effective way to address these issues. This paper investigates the spatial pattern of ecological migration and the corresponding spatiotemporal changes in land use and vegetation restoration in Gulang County, located in northwest China, between 2010 and 2018. For this purpose, we calculated three indicators: the transfer matrix of land use, normalized difference vegetation index (NDVI), and vegetation restoration degree (VRD). We found that ecological migrants in Gulang County moved from the Qilian Mountain National Park to the intersection between flat area and desert. The spatial patterns ranged from high-altitude to low-altitude, and the slopes became less steep. The distribution of the resettlements is more clustered and shaped by the traffic conditions and guided by the local governments. Unused land in the whole-village migration area and construction land in the resettlement area were dramatically impacted by ecological migration (625% and 279.3%, respectively). The cropland and construction land in the outmigration areas were mainly replaced with grassland and forest. In contrast, the grassland and unused land in the resettlement area were transferred to cropland and construction land. After ecological migration, the mean NDVI and VRD in Gulang County significantly increased, indicating that the vegetation in the outmigration areas quickly recovered. Moreover, the VRD in the whole-township migration areas was greater than that in the whole-village migration areas (121% > 68%). The main contribution to the increase in NDVI was the conversion of forest to grassland, accounting for 33%. In addition, the transition from other types of land to grassland made a larger contribution to the NDVI than conversions to forest.
Nexus between Coping Strategies and Households’ Agricultural Drought Resilience to Food Insecurity in South Africa
Authors: Bahta Yonas T.
Published: June 2022

Farmers in Africa, including those in South Africa, rely on rain-fed agriculture, which exposes them to the risks of agricultural drought. Agricultural drought has become a major threat to agricultural production, including the extreme mortality of livestock in recent years, thus negatively impacting household food security. Hence, this paper is aimed at (i) assessing the coping strategies employed by smallholding livestock-farming households during food insecurity shocks, and (ii) assessing the relationship between coping strategies and agricultural drought resilience to food insecurity in the Northern Cape Province of South Africa. Interviews, more specifically survey interviews, were conducted with 217 smallholder livestock farmers. The data was analyzed using the agricultural drought resilience index (ADRI), the household food insecurity access scale (HFIAS), and structural equation modeling. Smallholder livestock farming households utilized various coping strategies, ranging from selling livestock (21%) to leasing out their farms (1%). The coping strategies of farming households included using alternative land (20%), storing food (20%), requesting feed for their animals (16%), searching for alternative employment (6%), migrating (6%), raising drought-tolerant breeds (5%), receiving relief grants (3%) and using savings and investments (2%). A statistically significant relationship between coping strategies and agricultural drought resilience to food insecurity means that these strategies have important policy implications. Implementing strategies that encourage households to protect their livelihood and utilize their assets (selling livestock) to increase their resilience is crucial for reducing food insecurity and achieving the Sustainable Development Goals (SDGs) to end hunger and poverty.
Climatic Niche of Vegetation Greenness Is Likely to Be Conservative in Degraded Land
Authors: Li Guoqing , Huang Jinghua
Published: June 2022

Satellite data have been widely used to study changes in vegetation greenness in geographical space; however, this change is rarely considered in climatic space. Here, the climatic niche dynamics of vegetation greenness, represented by the normalized difference vegetation index (NDVI), was quantified in the climate space of the Loess Plateau, a piece of degraded land greening significantly from 2000 to 2018. The niche similarity test was used to examine the niche conservatism of vegetation greenness during the 19 years of restoration. The results show that the climate niche of vegetation greenness is always more similar than expected. The stability niche occupied most parts (83–98%) of their climatic niche, and niche overlap reached 0.52–0.69. Climate niche conservatism suggests that potential greenness constructed by statistical methods could be used as a criterion or baseline for ecosystem function restoration on the Loess Plateau. The study also suggests that the integrated niche similarity test in decision-making for restoration of degraded land will clarify our understanding of the climatic niche dynamics of vegetation greenness and the making of forecasts.
Evaluation of Ecosystem Service Change Patterns in a Mining-Based City: A Case Study of Wu’an City
Authors: Xiong Yuqing , Li Hong , Fu Meichen , Ma Xiuhua , Wang Lei
Published: June 2022

To coordinate the economy and environment in mining cities, it is critical to understand the ecological effects of land use/cover change (LUCC). Therefore, we selected a typical mining city to analyze LUCC-driven ecosystem service changes. In this study, we first used the equivalent factor method to calculate the ecosystem services valuation (ESV) in Wu’an and verified the rationality of the ESV coefficient through the sensitivity index. Secondly, ArcGIS was used to analyze the spatial change of ecosystem service value and explore the reasons for the change. Finally, the spatial autocorrelation index was calculated to analyze the spatial aggregation characteristics of ESV. The results showed that (1) between 2009 and 2018, the total value of ecosystem services decreased by USD 7.41 million, mainly due to the conversion of cropland to construction land. (2) The individual ecosystem services that contributed the most were waste disposal, water conservation, and soil conservation. The pollution caused by the development of mining has reduced the value of the waste disposal function, and the reduction in water body area has been the main factor limiting the water conservation function. (3) The areas with the most significant changes in ecosystem services were concentrated in the east-north direction, where mining resources were widely distributed, and near the central city. Furthermore, there were relatively small losses in the north-west direction, which was related to the protection of ecological resources influenced by topographical factors and less anthropogenic disturbance. (4) The value of ecosystem services and their dynamics exhibited obvious spatial autocorrelation and high-low value (HL) clustering in Wu’an. The high-value and low-value areas dissolved and penetrated each other, and the low-high value (LH) clustering and HL clustering were scattered. The high-value areas were mostly shown in strips, as they were the main locations of water bodies. This study is crucial for mining cities to maintain spatial stability and sustainable development, and the results provide a scientific basis for land use management decision makers to regulate land more precisely.
The Impact of the Accessibility of Transportation Infrastructure on the Non-Farm Employment Choices of Rural Laborers: Empirical Analysis Based on China’s Micro Data
Authors: Huang Qiuyi , Zheng Xiaoping , Wang Ruimei
Published: June 2022

Non-agricultural employment plays a significant role in alleviating regional poverty. Using the micro data of the China Labor-Dynamics Survey (CLDS), this paper empirically analyzes the impact of the accessibility of rural transportation infrastructure on the non-agricultural employment choices of rural laborers by using the entropy method and the ordered Logit model. The results show that there is a significant positive correlation between the accessibility of rural transportation infrastructure and the non-agricultural employment of rural laborers. The study also finds that the laborers participating in non-agricultural employment in villages with good transportation infrastructure will prefer to be employed in nearby locations, and the development of the rural non-agricultural economy is an important reason. Further analysis clearly shows that gender, the family dependency ratio, and rural terrain characteristics affect the choices made by laborers with respect to non-agricultural employment. Based on the research results, focusing on a transportation and industry model and considering the construction of transportation infrastructure as a guide, especially in areas with poor terrain, promoting the development of rural non-agricultural industries can help solve the problem in rural areas and in women’s employment where family members or accompanying personnel are left behind, and can promote the orderly transfer of rural laborers.
Characterization of Aurintricarboxylic Acid (ATA) Interactions with Plasma Transporter Protein and SARS-CoV-2 Viral Targets: Correlation of Functional Activity and Binding Energetics
Authors: Minetti Conceição A. , Remeta David P. , Hashimoto Keiji , Bonala Radha , Chennamshetti Rajesh , Yin Xingyu , Garcia-Diaz Miguel , Grollman Arthur P. , Johnson Francis , Sidorenko Viktoriya S.
Published: June 2022

In an effort to identify functional-energetic correlations leading to the development of efficient anti-SARS-CoV-2 therapeutic agents, we have designed synthetic analogs of aurintricarboxylic acid (ATA), a heterogeneous polymeric mixture of structurally related linear homologs known to exhibit a host of biological properties, including antiviral activity. These derivatives are evaluated for their ability to interact with a plasma transporter protein (human serum albumin), eukaryotic (yeast) ribosomes, and a SARS-CoV-2 target, the RNA-dependent RNA polymerase (RdRp). The resultant data are critical for characterizing drug distribution, bioavailability, and effective inhibition of host and viral targets. Promising lead compounds are selected on the basis of their binding energetics which have been characterized and correlated with functional activities as assessed by inhibition of RNA replication and protein synthesis. Our results reveal that the activity of heterogeneous ATA is mimicked by linear compounds of defined molecular weight, with a dichlorohexamer salicylic-acid derivative exhibiting the highest potency. These findings are instrumental for optimizing the design of structurally defined ATA analogs that fulfill the requirements of an antiviral drug with respect to bioavailability, homogeneity, and potency, thereby expanding the arsenal of therapeutic regimens that are currently available to address the urgent need for effective SARS-CoV-2 treatment strategies.
2-(3-Bromophenyl)-8-fluoroquinazoline-4-carboxylic Acid as a Novel and Selective Aurora A Kinase Inhibitory Lead with Apoptosis Properties: Design, Synthesis, In Vitro and In Silico Biological Evaluation
Authors: Elsherbeny Mohamed H. , Ammar Usama M. , Abdellattif Magda H. , Abourehab Mohammed A. S. , Abdeen Ahmed , Ibrahim Samah F. , Abdelrahaman Doaa , Mady Wessam , Roh Eun Joo , Elkamhawy Ahmed
Published: June 2022

New quinazoline derivatives were designed based on the structural modification of the reported inhibitors to enhance their selectivity toward Aurora A. The synthesized compounds were tested over Aurora A, and a cytotoxicity assay was performed over NCI cell lines to select the best candidate for further evaluation. Compound 6e (2-(3-bromophenyl)-8-fluoroquinazoline-4-carboxylic acid) was the most potent compound among the tested derivatives. A Kinase panel assay was conducted for compound 6e over 14 kinases to evaluate its selectivity profile. Further cell cycle and apoptosis analysis were evaluated for compound 6e over the MCF-7 cell line at its IC50 of 168.78 µM. It arrested the cell cycle at the G1 phase and induced apoptosis. Molecular docking was performed to explore the possible binding mode of compound 6e into the active site. It showed significant binding into the main pocket in addition to potential binding interactions with the key amino acid residues. Accordingly, compound 6e can be considered a potential lead for further structural and molecular optimization of the quinazoline-based carboxylic acid scaffold for Aurora A kinase selective inhibition with apoptosis properties.
High Glycated Hemoglobin Instead of High Body Mass Index Might Increase the Urine N-Acetyl-β-D-glucosaminidase Con-Centration in Children and Adolescents with Diabetes Mellitus
Authors: Suh Jin-Soon , Cho Kyoung Soon , Kim Seul Ki , Kim Shin-Hee , Cho Won Kyoung , Jung Min Ho , Ahn Moon Bae
Published: June 2022

Children with diabetes, and particularly those with obesity, have poor glycemic control. They are thus at higher risk of early microvascular complications. Renal tubulointerstitial markers are integral to evaluating diabetic nephropathy. Various biomarkers have been proposed, but their role in the obese pediatric population is uncertain. We investigated renal injury markers in children with diabetes, according to obesity, and determined their role as early predictors of diabetic nephropathy. Fifty-three children and adolescents, diagnosed with either type 1 or 2 diabetes mellitus, and 43 control children, aged 7–18 years, were included. Clinical and laboratory characteristics, including six renal injury markers, were compared among subjects according to body mass index and presence of diabetes mellitus. Urine neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, and N-acetyl-β-D-glucosaminidase (NAG) showed significant difference between controls and diabetic children, whereas urine NAG was the only biomarker that was significantly lower either in non-obese or obese controls as compared to diabetic children. Urine NGAL, KIM-1, and NAG showed significant correlations with both HbA1c and urine ACR, whereas only urine NAG was significantly correlated with HbA1c even when groups were subdivided based on the presence of either obesity or diabetes. After adjusting for age, sex, body mass index, duration of known diabetes, and urine albumin-to-creatinine ratio, HbA1c remained a significant risk factor for elevated urine NAG. Urine NAG could be a useful indicator of tubulointerstitial damage in children with diabetes in the pre-albuminuric state. Tighter glycemic control appears to be crucial for avoiding early progression to diabetic nephropathy.
Cancer Cachexia and Antitumor Immunity: Common Mediators and Potential Targets for New Therapies
Authors: Rounis Konstantinos , Makrakis Dimitrios , Gioulbasanis Ioannis , Ekman Simon , De Petris Luigi , Mavroudis Dimitris , Agelaki Sofia
Published: June 2022

Cancer cachexia syndrome (CCS) is a multifactorial metabolic syndrome affecting a significant proportion of patients. CCS is characterized by progressive weight loss, alterations of body composition and a systemic inflammatory status, which exerts a major impact on the host’s innate and adaptive immunity. Over the last few years, the development of immune checkpoint inhibitors (ICIs) transformed the treatment landscape for a wide spectrum of malignancies, creating an unprecedented opportunity for long term remissions in a significant subset of patients. Early clinical data indicate that CCS adversely impairs treatment outcomes of patients receiving ICIs. We herein reviewed existing evidence on the potential links between the mechanisms that promote the catabolic state in CCS and those that impair the antitumor immune response. We show that the biological mediators and processes leading to the development of CCS may also participate in the modulation and the sustainment of an immune suppressive tumor microenvironment and impaired anti-tumor immunity. Moreover, we demonstrate that the deregulation of the host’s metabolic homeostasis in cancer cachexia is associated with resistance to ICIs. Further research on the interrelation between cancer cachexia and anti-tumor immunity is required for the effective management of resistance to immunotherapy in this specific but large subgroup of ICI treated individuals.
Study on Factors Influencing Film Formation of Grease and Calculation Model for Grease Film Thickness
Authors: Zhang Zhe , Wang Yanshuang , Lin Jianghai , Wang Dongfeng
Published: June 2022

The grease film thickness was measured in fully flooded elastohydrodynamic lubrication, and the influence of rolling speed, load, consistency, base oil type and thickener type on grease film thickness was analyzed. A new calculation model for grease film thickness was established. The results show that the grease film thickness increases with the increasing rolling speed, and then levels off with the amount of thickener in the contact region reaching an equilibrium. The degree of grease film enhancement comparing to its base oil will depend on thickener type and consistency. The larger the atmospheric viscosity and pressure-viscosity coefficient of the base oil, the higher the film thickness of the greases with the same thickener. The grease film thicknesses with the same base oil and different thickeners are determined by the size of thickener particles at the same consistency or concentration. The larger the consistence of the grease, the larger the effective viscosity of the grease at the contact and the thicker the grease film thickness whose base oil has the same type and viscosity along with the same type of thickener. The calculated values by the new model are in good agreement with the measured values.
Cytotoxic Potential of Bio-Silica Conjugate with Different Sizes of Silver Nanoparticles for Cancer Cell Death
Authors: Hamdy Mohamed S. , Elbehairi Serag Eldin I. , Shati Ali A. , Abd-Rabboh Hisham S. M. , Alfaifi Mohammad Y. , Fawy Khaled F. , Ibrahium Hala A. , Alamri Saad , Awwad Nasser S.
Published: June 2022

Well-defined silver nanoparticles were doped into bio-based amorphous silica (Ag-b-SiO2) with different silver contents (from 2 to 20 wt%) by a solvent-free procedure. The four as-synthetized samples were hydrogenated at 300 °C to ensure the formation of zero-valent Ag nanoparticles. The prepared samples were characterized by X-ray powder diffraction (XRD), elemental analysis, N2 sorption measurements, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). The characterization data confirmed the formation of well-defined zero-valent silver nanoparticles in the range of 3–10 nm in the low-loading samples, while in high-loading samples, bulky particles of silver in the range of 200–500 nm were formed. The in vitro cytotoxic activities of the Ag-b-SiO2 samples were tested against the tumor cell lines of breast (MCF-7), liver (HepG2), and colon (HCT 116) over a concentration range of 0.01 to 1000 g. The prepared samples exhibited a wide range of cytotoxic activities against cancer cells. An inverse relationship was observed between the silver nanoparticles’ size and the cytotoxic activity, while a direct relationship between the silver nanoparticles’ size and the apoptotic cell death was noticed.
The Effect of Pore Structure on Impact Behavior of Concrete Hollow Brick, Autoclaved Aerated Concrete and Foamed Concrete
Authors: Liu Jian , Ren Yuzhe , Chen Rui , Wu Yuedong , Lei Weidong
Published: June 2022

Porous concrete is an energy absorption material, which has been widely used in civil engineering, traffic engineering and disaster reduction engineering. However, the effect of pore structure on the impact behavior of the porous concrete is lacked. In this study, a series of drop-weight impact tests were carried out on three typical types of porous concrete, i.e., concrete hollow brick (CHB), autoclaved aerated concrete (AAC) and foamed concrete (FC), to investigate the effect of pore structures on their impact behavior. For comparison, static load tests were also conducted as references. According to the damage to the samples, the developments of impact force, strain, contact stress–strain relationship and absorbed energy during drop-weight during the impact test were measured and analyzed. The results show that the ratio between the peak impact stress and compressive strength of CHB was 0.44, while that of AAC and FC increased to about 0.6, indicating that the small and uniform pore structure in AAC and FC had a higher resistance against impact load than the hollow cavity of CHB. In addition, the elastic recovery strain in AAC increased by about 0.2% and its strain at peak contact stress increased by about 160% for a comparison of CHB, implying that a small open pore structure could enhance ductility. Besides, the peak contact stress of FC was close to that of AAC during impact loading, while the strain at peak contact stress of FC increased by about 36% compared with AAC, revealing that the closed-pore structure could further enhance the deformation potential. Correspondingly, the energy absorption rates of CHB, AAC and FC were 85.9 kJ/s, 54.4 kJ/s and 49.7 kJ/s, respectively, where AAC decreased by about 58% compared with CHB, and FC decreased by about 10% compared with AAC.
Nanostructured Layer of Silver for Detection of Small Biomolecules in Surface-Assisted Laser Desorption Ionization Mass Spectrometry
Authors: Arendowski Adrian , Sagandykova Gulyaim , Mametov Radik , Rafińska Katarzyna , Pryshchepa Oleksandra , Pomastowski Paweł
Published: June 2022

A facile approach for the synthesis of a silver nanostructured layer for application in surface-assisted laser desorption/ionization mass spectrometry of low-molecular-weight biomolecules was developed using electrochemical deposition. The deposition was carried out using the following silver salts: trifluoroacetate, acetate and nitrate, varying the voltage and time. The plate based on trifluoroacetate at 10 V for 15 min showed intense SALDI-MS responses for standards of various classes of compounds: fatty acids, cyclitols, saccharides and lipids at a concentration of 1 nmol/spot, with values of the signal-to-noise ratio ≥50. The values of the limit of detection were 0.71 µM for adonitol, 2.08 µM for glucose and 0.39 µM for palmitic acid per spot. SEM analysis of the plate showed anisotropic flower-like microstructures with nanostructures on their surface. The reduced chemical background in the low-mass region can probably be explained by the absence of stabilizers and reducing agents during the synthesis. The plate synthesized with the developed approach showed potential for future use in the analysis of low-molecular-weight compounds of biological relevance. The absence of the need for the utilization of sophisticated equipment and the synthesis time (10 min) may benefit large-scale applications of the layer for the detection of various types of small biomolecules.
Applying the FMR Technique to Analyzing the Influence of Nitriding on the Magnetic Properties of Steel
Authors: Kaczmarek Slawomir Maksymilian , Michalski Jerzy , Leniec Grzegorz , Fuks Hubert , Frączek Tadeusz , Dudek Agata
Published: June 2022

This paper presents the relationship between the chemical composition and size of steel balls, the parameters of the nitriding process, and their magnetic properties, defined in this study by ferromagnetic resonance (FMR) and SQUID. Balls made from AISI 1010 and AISI 52100 steels, with diameters of 2.5 and 3 mm, respectively, were investigated. On samples made of AISI 1010 and AISI 52100 steel, single-phase layers of iron nitrides γ’ with a thickness of gmp = 50 and 37 μm, respectively, were produced. Then, the samples were annealed at a temperature of 520 °C for 4 h in an inert atmosphere (N2/Ar) at a pressure of 200 Pa. After the nitriding processes, steel balls were subjected to standard physical metallurgy and X-ray examinations. During annealing of nitrided layers with a two-phase layer of iron nitrides, at first, the transformation of the ε phase into the γ’ phase with the release of nitrogen into the atmosphere takes place. The FMR signals did not originate from isolated ions, but from more magnetically complex systems, e.g., Fe–Fe pairs or iron clusters, while the observed FMR line position is normally even lower and occurs for a magnetic induction below 200 mT. The fact that the magnetic centers did not contain mainly isolated Fe ions, additionally confirmed the abnormal increase in resonance signal intensity as a function of temperature, which is a behavior inconsistent with the Curie–Weiss law. The results obtained from measurements by the SQUID method, recording variations in magnetization as a function of temperature, confirm the untypical reinforcement of the magnetic conditions of the samples with the increase in temperature. For the samples tested, the magnetization was relatively weaker when the tests were conducted in a stronger magnetic field.
Novel Van Der Waals Heterostructures Based on Borophene, Graphene-like GaN and ZnO for Nanoelectronics: A First Principles Study
Authors: Slepchenkov Michael M. , Kolosov Dmitry A. , Glukhova Olga E.
Published: June 2022

At present, the combination of 2D materials of different types of conductivity in the form of van der Waals heterostructures is an effective approach to designing electronic devices with desired characteristics. In this paper, we design novel van der Waals heterostructures by combing buckled triangular borophene (tr-B) and graphene-like gallium nitride (GaN) monolayers, and tr-B and zinc oxide (ZnO) monolayers together. Using ab initio methods, we theoretically predict the structural, electronic, and electrically conductive properties of tr-B/GaN and tr-B/ZnO van der Waals heterostructures. It is shown that the proposed atomic configurations of tr-B/GaN and tr-B/ZnO heterostructures are energetically stable and are characterized by a gapless band structure in contrast to the semiconductor character of GaN and ZnO monolayers. We find the phenomenon of charge transfer from tr-B to GaN and ZnO monolayers, which predetermines the key role of borophene in the formation of the features of the electronic structure of tr-B/GaN and tr-B/ZnO van der Waals heterostructures. The results of the calculation of the current–voltage (I–V) curves reveal that tr-B/GaN and tr-B/ZnO van der Waals heterostructures are characterized by the phenomenon of current anisotropy: the current along the zigzag edge of the ZnO/GaN monolayers is five times greater than along the armchair edge of these monolayers. Moreover, the heterostructures show good stability of current to temperature change at small voltage. These findings demonstrate that r-B/GaN and tr-B/ZnO vdW heterostructures are promising candidates for creating the element base of nanoelectronic devices, in particular, a conducting channel in field-effect transistors.
Experimental Case Studies about Uniplanar SHS Joints with Full-Overlapped Top Connection
Authors: Heinemann Patrick , Isopescu Dorina-Nicolina
Published: June 2022

Squared hollow steel profiles are commonly used in the construction of offshore structures or building facades. By welding two or more pipes, typical joints are created that are specific for different areas of applications. These joints are less resistant than straight pipes due to the geometrical heterogeneity and the complex stress behavior of the welding. Standards define these joints, but there are restrictions imposed regarding the material or geometry. This paper focused on full-overlapped joints with squared hollow section profiles and on-top connection, which are disregarded in current standards. The aim was to figure out the influence of the inclination angle on the resistance of the joint. In the analysis, experimental and numerical studies were performed. Four different inclination angles commonly used on construction sites were the focus. It was discovered that there is a total diminishment of 46% in the load bearing capacity between the steepest and the most obtuse angles. The structural behavior is non-linear and is influenced by the value of the angles. The second aspect is related to the influence of the steel profile, which is evaluated by a comparison between a squared profile and two circular profiles. It was discovered that the joint made with squared profiles has a higher bearing capacity than the one made with circular profiles, a statement valid for similar thicknesses of the elements.
Effect of Corrosive Medium and Surface Defect-Energy on Corrosion Behavior of Rolled ZK61M Alloy
Authors: Sun Jie , Zhao Wenxiang , Yan Pei , Chen Kaijie , Jiao Li , Qiu Tianyang , Wang Xibin
Published: June 2022

Magnesium alloys have been widely used as lightweight engineering structural materials, but their service performances are severely restricted by corrosion failure. In this paper, the influence of corrosive medium and surface defect energy on the corrosion behavior of rolled ZK61M alloy was investigated. The corrosion tests were conducted in different concentrations of sodium chloride solution for different durations, and the polarization curves and electrochemical impedance spectroscopy were reported. The surface morphology of rolled ZK61M alloy before and after corrosion tests were analyzed. The results showed that the corrosion tendency became stronger with the increase of the concentration of corrosive medium and the number of surface defects of ZK61M alloy. Moreover, the initial corrosion pattern was the pitting caused by micro galvanic corrosion at the surface defect, which gradually developed into uniform corrosion. Furthermore, the main damage occurred at the grain boundary, resulting in the destruction of grain bonding force and the removal of material along the rheological layer. The oxidation corrosion mechanism was mainly the anodic dissolution mechanism.
Implications of Microstructure in Helium-Implanted Nanocrystalline Metals
Authors: Nathaniel James E. , El-Atwani Osman , Huang Shu , Marian Jaime , Leff Asher C. , Baldwin Jon K. , Hattar Khalid , Taheri Mitra L.
Published: June 2022

Helium bubbles are known to form in nuclear reactor structural components when displacement damage occurs in conjunction with helium exposure and/or transmutation. If left unchecked, bubble production can cause swelling, blistering, and embrittlement, all of which substantially degrade materials and—moreover—diminish mechanical properties. On the mission to produce more robust materials, nanocrystalline (NC) metals show great potential and are postulated to exhibit superior radiation resistance due to their high defect and particle sink densities; however, much is still unknown about the mechanisms of defect evolution in these systems under extreme conditions. Here, the performances of NC nickel (Ni) and iron (Fe) are investigated under helium bombardment via transmission electron microscopy (TEM). Bubble density statistics are measured as a function of grain size in specimens implanted under similar conditions. While the overall trends revealed an increase in bubble density up to saturation in both samples, bubble density in Fe was over 300% greater than in Ni. To interrogate the kinetics of helium diffusion and trapping, a rate theory model is developed that substantiates that helium is more readily captured within grains in helium-vacancy complexes in NC Fe, whereas helium is more prone to traversing the grain matrices and migrating to GBs in NC Ni. Our results suggest that (1) grain boundaries can affect bubble swelling in grain matrices significantly and can have a dominant effect over crystal structure, and (2) an NC-Ni-based material can yield superior resistance to irradiation-induced bubble growth compared to an NC-Fe-based material and exhibits high potential for use in extreme environments where swelling due to He bubble formation is of significant concern.
Histological Evaluation of Restylane Lyft Used as a Scaffold for Dental Pulp Regeneration in Non-Infected Immature Teeth in Dogs
Authors: AlHowaish Norah A. , AlSudani Dina I. , Khounganian Rita , AlMuraikhi Nehal
Published: June 2022

Commercially available hyaluronic acid dermal fillers used as a scaffold in regenerative endodontic procedures (REPs) have demonstrated attractive potentials. This study aimed to histologically evaluate the outcome of REPs using Restylane Lyft (HA) as a scaffold. REPs were performed on pulpless, immature roots in dogs (n = 69). The roots were divided into four groups: blood clot (BC), Restylane Lyft (BC + HA), negative control, and positive control. At 13 weeks postoperatively, hard tissue formation, vascularization, the presence of vascularized soft connective tissue and collagen fibers, the degree of inflammation within pulp spaces and/or periapical tissues, and apical closure were evaluated histologically. The vascularization and formation of loosely arranged collagen fibers within the regenerated soft connective tissues were observed significantly more in the BC+HA group (85% and 40%, respectively; p < 0.05) compared to the BC group (54.6% and 9.1%, respectively; p < 0.05). The degree of inflammation was significantly higher in the HA group than in the BC group; moderate to severe inflammatory cell infiltration was seen in 45% and 13.6% of the cases, respectively. The results of the present study suggest that Restylane Lyft combined with a blood clot used as a scaffold may improve the outcomes of REPs in non-infected, pulpless, immature teeth in dogs.
Electrochemical Study of Semiconductor Properties for Bismuth Silicate-Based Photocatalysts Obtained via Hydro-/Solvothermal Approach
Authors: Shabalina Anastasiia , Gotovtseva Ekaterina , Belik Yulia , Kuzmin Sergey , Kharlamova Tamara , Kulinich Sergei , Svetlichnyi Valery , Vodyankina Olga
Published: June 2022

Three bismuth silicate-based photocatalysts (composites of Bi2SiO5 and Bi12SiO20) prepared via the hydro-/solvothermal approach were studied using electrochemical methods. The characteristic parameters of semiconductors, such as flat band potential, donor density, and mobility of their charge carriers, were obtained and compared with the materials’ photocatalytic activity. An attempt was made to study the effect of solution components on the semiconductor/liquid interface (SLI). In particular, the Mott–Schottky characterization was made in a common model electrolyte (Na2SO4) and with the addition of glycerol as a model organic compound for photocatalysis. Thus, a medium close to those in photocatalytic experiments was simulated, at least within the limits allowed by electrochemical measurements. Zeta-potential measurements and electrochemical impedance spectroscopy were used to reveal the processes taking place at the SLI. It was found that the medium in which measurements were carried out dramatically impacted the results. The flat band potential values (Efb) obtained via the Mott–Schottky technique were shown to differ significantly depending on the solution used in the experiment, which is explained by different processes taking place at the SLI. A strong influence of specific adsorption of commonly used sulfate ions and neutral molecules on the measured values of Efb was shown.