bluuebunny/crossref_metadata_2025 huggingface dataset:
Serosurvey of Nonhuman Primates in Costa Rica at the Human–Wildlife Interface Reveals High Exposure to Flaviviruses
Authors: Chaves Andrea , Piche-Ovares Martha , Ibarra-Cerdeña Carlos N. , Corrales-Aguilar Eugenia , Suzán Gerardo , Moreira-Soto Andres , Gutiérrez-Espeleta Gustavo A.
Published: June 2021

Arthropod-borne viruses belonging to the flavivirus genus possess an enormous relevance in public health. Neotropical non-human primates (NPs) have been proposed to be susceptible to flavivirus infections due to their arboreal and diurnal habits, their genetic similarity to humans, and their relative closeness to humans. However, the only known flavivirus in the American continent maintained by sylvatic cycles involving NPs is yellow fever virus (YFV), and NPs’ role as potential hosts of other flaviviruses is still unknown. Here, we examined flavivirus exposure in 86 serum samples including 83.7% samples from free-range and 16.3% from captive NPs living in flavivirus-endemic regions of Costa Rica. Serum samples were opportunistically collected throughout Costa Rica in 2000–2015. We used a highly specific micro-plaque reduction neutralization test (micro-PRNT) to determine the presence of antibodies against YFV, dengue virus 1–4 (DENV), Zika virus, West Nile virus (WNV), and Saint Louis encephalitis virus (SLEV). We found evidence of seropositive NPs with homotypic reactivity to SLEV 11.6% (10/86), DENV 10.5% (9/86), and WNV 2.3% (2/86). Heterotypic reactivity was determined in 3.5% (3/86) of individuals against DENV, 1.2% (1/86) against SLEV, and 1.2% (1/86) against WNV. We found that 13.9% (12/86) of NPs were positive for an undetermined flavivirus species. No antibodies against DENV-3, DENV-4, YFV, or ZIKV were found. This work provides compelling serological evidence of flavivirus exposure in Costa Rican NPs, in particular to DENV, SLEV, and WNV. The range of years of sampling and the region from where positives were detected coincide with those in which peaks of DENV in human populations were registered, suggesting bidirectional exposure due to human–wildlife contact or bridging vectors. Our work suggests the continuous exposure of wildlife populations to various flaviviruses of public health importance and underscores the necessity of further surveillance of flaviviruses at the human–wildlife interface in Central America.
Novel RNA Viruses from the Transcriptome of Pheromone Glands in the Pink Bollworm Moth, Pectinophora gossypiella
Authors: Dou Xiaoyi , Liu Sijun , Soroker Victoria , Harari Ally , Jurenka Russell
Published: June 2021

In this study, we analyzed the transcriptome obtained from the pheromone gland isolated from two Israeli populations of the pink bollworm Pectinophora gossypiella to identify viral sequences. The lab population and the field samples carried the same viral sequences. We discovered four novel viruses: two positive-sense single-stranded RNA viruses, Pectinophora gossypiella virus 1 (PecgV1, a virus of Iflaviridae) and Pectinophora gossypiella virus 4 (PecgV4, unclassified), and two negative-sense single-stranded RNA viruses, Pectinophora gossypiella virus 2 (PecgV2, a virus of Phasmaviridae) and Pectinophora gossypiella virus 3 (PecgV3, a virus of Phenuiviridae). In addition, sequences derived from two negative-sense single-stranded RNA viruses that belong to Mononegavirales were found in the data. Analysis of previous transcriptome sequencing data derived from the midgut of pink bollworm larvae of a USA population only identified PecgV1, but no other viruses. High viral sequence coverages of PecgV1 and PecgV4 were observed in both field and lab populations. This is the first report of viral sequences discovered from the pink bollworm. Results from this investigation suggest that the pink bollworm harbors multiple viruses. Further investigation of the viral pathogens may help to develop novel pest management strategies for control of the pink bollworm.
Combined and Sequential Treatment with Deep Brain Stimulation and Continuous Intrajejunal Levodopa Infusion for Parkinson’s Disease
Authors: van Poppelen Daniël , Tromp Annelie N.M. , de Bie Rob M.A. , Dijk Joke M.
Published: June 2021

(1) Background: Deep brain stimulation (DBS) and continuous intrajejunal levodopa infusion (CLI) are efficacious treatments of medication related motor response fluctuations in advanced Parkinson’s disease (PD). Literature regarding the use of both advanced treatments within one patient is scarce. (2) Methods: We present a retrospective single center case series and a review of the literature. Patients with PD who were treated with both DBS and CLI in our tertiary referral center between 2005 and 2020 were identified and medical records were assessed. Additionally, literature on patients treated with both therapies was systematically searched for in Medline and Embase. (3) Results: Nineteen patients were included. Medication related motor response fluctuations were a major indication for the second therapy in all but one. Of nine patients initially treated with DBS, five reported improvement with CLI. Seven of ten patients initially treated with CLI experienced benefits from DBS. The systematic literature search resulted in fifteen previous publications comprising 66 patients. Of the 59 patients, for whom the effect of the second treatment was known, 57 improved. (4) Conclusions: PD patients, who have persisting medication related motor response fluctuations, despite DBS or CLI treatment, may benefit from an additional or alternative treatment with either CLI or DBS.
Updates on Robotic CME for Right Colon Cancer: A Qualitative Systematic Review
Authors: Petz Wanda , Borin Simona , Fumagalli Romario Uberto
Published: June 2021

Background. Complete mesocolic excision (CME) is a surgical technique introduced with the aim of ameliorating the oncologic results of colectomy. Various experiences have demonstrated favorable oncologic results of CME in comparison with standard colectomy, in which the principles of CME are not respected. The majority of the literature refers to open or laparoscopic CME. This review analyses current evidence regarding robotic CME for right colectomy. Methods. An extensive Medline (Pub Med) search for relevant case series, restricted to papers published in English, was performed, censoring video vignettes and case reports. Results. Fourteen studies (ten retrospective, four comparative series of robotic versus laparoscopic CME) were included, with patient numbers ranging from 20 to 202. Four different approaches to CME are described, which also depend on the robotic platform utilized. Intraoperative and early clinical results were good, with a low conversion and anastomotic leak rate and a majority of Clavien–Dindo complications being Grades I and II. Oncologic adequacy of the surgical specimens was found to be good, although a homogeneous histopathologic evaluation was not provided. Conclusions. Further large studies are warranted to define long-term oncologic results of robotic right colectomy with CME and its eventual benefits in comparison to laparoscopy.
Robotic versus Laparoscopic Surgery for Spleen-Preserving Distal Pancreatectomies: Systematic Review and Meta-Analysis
Authors: Rompianesi Gianluca , Montalti Roberto , Ambrosio Luisa , Troisi Roberto Ivan
Published: June 2021

Background: When oncologically feasible, avoiding unnecessary splenectomies prevents patients who are undergoing distal pancreatectomy (DP) from facing significant thromboembolic and infective risks. Methods: A systematic search of MEDLINE, Embase, and Web Of Science identified 11 studies reporting outcomes of 323 patients undergoing intended spleen-preserving minimally invasive robotic DP (SP-RADP) and 362 laparoscopic DP (SP-LADP) in order to compare the spleen preservation rates of the two techniques. The risk of bias was evaluated according to the Newcastle–Ottawa Scale. Results: SP-RADP showed superior results over the laparoscopic approach, with an inferior spleen preservation failure risk difference (RD) of 0.24 (95% CI 0.15, 0.33), reduced open conversion rate (RD of −0.05 (95% CI −0.09, −0.01)), reduced blood loss (mean difference of −138 mL (95% CI −205, −71)), and mean difference in hospital length of stay of −1.5 days (95% CI −2.8, −0.2), with similar operative time, clinically relevant postoperative pancreatic fistula (ISGPS grade B/C), and Clavien–Dindo grade ≥3 postoperative complications. Conclusion: Both SP-RADP and SP-LADP proved to be safe and effective procedures, with minimal perioperative mortality and low postoperative morbidity. The robotic approach proved to be superior to the laparoscopic approach in terms of spleen preservation rate, intraoperative blood loss, and hospital length of stay.
Photobiological Neuromodulation of Resting-State EEG and Steady-State Visual-Evoked Potentials by 40 Hz Violet Light Optical Stimulation in Healthy Individuals
Authors: Noda Yoshihiro , Takano Mayuko , Hayano Motoshi , Li Xuemei , Wada Masataka , Nakajima Shinichiro , Mimura Masaru , Kondo Shinichiro , Tsubota Kazuo
Published: June 2021

Photobiological neuromodulation and its clinical application has been investigated in recent years. The response of the gamma-oscillation to human visual stimuli is known to be both burst and resonant in nature, and the coupling between alpha and gamma oscillations may play a functional role in visual processing. To date, there is no study that examined the effects of gamma-frequency violet light (VL) stimulation on human electroencephalography (EEG). In this study, we investigated the neurophysiological changes induced by light stimulation using EEG. The purpose of this study was to evaluate the specific effects of 40 Hz gamma-frequency VL stimulation on EEG activity by comparing the effects of white light (WL) with the same condition. Twenty healthy participants (10 females: 37.5 ± 14.3 years; 10 males: 38.0 ± 13.3 years) participated in this study and the following results were observed. First, when compared with the power spectrum density (PSD) of baseline EEG, 40 Hz-WL induced significant increase of PSD in theta band. Second, compared the PSDs between EEG with 40 Hz-VL and EEG with 40 Hz-WL, 40 Hz-VL induced significantly lower enhancement in delta and theta bands than 40 Hz-WL. Third, when focused on the occipital area, negative peak of VEP with 40 Hz-VL was smaller than that of 40 Hz-WL. Fourth, 40 Hz-VL induced an increase of alpha-gamma coupling during the VEP at the F5 electrode site as well as post-EEG at the C4 electrode site, compared with baseline EEG. Thus, the present study suggested that 40 Hz-VL stimulation may induce unique photobiological neuromodulations on human EEG activity.
Capacity Control in Indoor Spaces Using Machine Learning Techniques Together with BLE Technology
Authors: Beato Gutiérrez M. Encarnación , Sánchez Montserrat Mateos , Berjón Gallinas Roberto , Fermoso García Ana M.
Published: June 2021

At present, capacity control in indoor spaces is critical in the current situation in which we are living in, due to the pandemic. In this work, we propose a new solution using machine learning techniques with BLE technology. This study presents a real experiment in a university environment and we study three different prediction models using machine learning techniques—specifically, logistic regression, decision trees and artificial neural networks. As a conclusion, the study shows that machine learning techniques, in particular decision trees, together with BLE technology, provide a solution to the problem. The contribution of this research work shows that the prediction model obtained is capable of detecting when the COVID capacity of an enclosed space is exceeded. In addition, it ensures that no false negatives are produced, i.e., all the people inside the laboratory will be correctly counted.
The Mediating Role of Social Capital in Digital Information Technology Poverty Reduction an Empirical Study in Urban and Rural China
Authors: Liu Zhen , Wei Yiming , Li Qiuming , Lan Jing
Published: June 2021

Widespread use of digital information technology is having a significant impact on economic growth and people’s well-being. This paper assesses the mediating role of social capital in the impact of digital information technology on multidimensional poverty. Due to differences in regional, industrial structure and other factors, digital information technology has different impacts on urban and rural residents. In this paper, the China Family Panel Studies (CFPS) database is used for data, and a mediating effect model is used to study the problem. The digital information technology use was found to enhance social capital from social network, social participation and social trust, and subsequently alleviates multidimensional poverty. The results indicate that social trust plays a more significant mediating role than social capital and social participation on the impact of digital information technology on multidimensional poverty. Furthermore, the results reveal that the use of digital information technology has varying effects on poverty reduction among different income groups, with a much higher effect on low-income groups. However, the mediating effect of social capital in high-income groups is higher than that in low-income groups. In particular, social capital in the top 25% of income groups has the highest mediating effect. In the heterogeneity analysis between urban and rural areas, it is found that the multidimensional poverty situation in urban areas is significantly better than that in rural areas, because urban residents have a higher use of digital information, and at the same time, the quality of social capital in urban and rural groups is different, leading to the difference in the effect of digital information technology on poverty reduction of multidimensional poverty. Based on the results of the study, we believe that the use of digital information technology has actually improved the multi-dimensional poverty status of all groups, and social capital plays a key mediating role in it. Relying on the progress of digital information technology, we can build more convenient social network. Establish more adequate channels of information communication, enhance social trust and social participation, and alleviate multidimensional poverty.
A Lens for Analysis of Payment for Ecosystem Services Systems: Transitioning the Working Lands Economic Sector from Extractive Industry to Regenerative System
Authors: Merrick Gordon N.
Published: June 2021

Payment for Ecosystem Services (PES) systems are gaining attention worldwide. These systems are an increasingly used incentive structure for conservation, presenting a significant opportunity for science to impact and shape commerce. However, PES systems lack a unifying framework to analyze and evaluate them from multiple perspectives, including ecological revitalization alongside economic and social revitalization. In this study, I formulate a new analytical framework that accommodates both public and private PES systems, and test the framework with hypotheticals from both systems. Utilizing the framework developed, this article shows that publicly-operated PES systems function optimally, as a public system provides optimized benefits regarding societal and ecological outcomes, now and for future generations.
Dual Covalent Cross-Linking Networks in Polynorbornene: Comparison of Shape Memory Performance
Authors: Zhao Haotian , Zhang Qinghong , Wen Xinlong , Wang Gongliang , Gong Xiaowen , Shi Xinyan
Published: June 2021

In this work, tetrakis(dimethyllamino)ethylene (TDAE) plasticized polynorbornene (PNB) was used as the matrix, sulfur (S) and dicumyl peroxide (DCP) were simultaneously used as crosslinking agents to construct dual covalent cross-linking networks in PNB. The effects of different amounts of cross-linkers on the crosslinking degree, mechanical property, glass transition temperature, and PNB shape memory performance were investigated. Two crosslinking mechanisms were examined by Fourier transform infrared spectrometer and Raman spectrometer. The results showed that sulfur-rich cross-linked PNB exhibited a higher crosslinking degree, tensile strength, and slightly higher glass transition temperature than the DCP-rich system. Cross-linked PNB presented better shape memory performance than the uncross-linked one. Sulfur-rich cross-linked PNB showed even better shape memory behavior than the DCP-rich system, both with a shape fixation ratio of over 99% and a shape recovery ratio of over 90%. The reaction mechanism of sulfur and DCP in cross-linking PNB was different. Sulfur reacted with the α-H in PNB to form monosulfide bonds, disulfide bonds, and polysulfide bonds in PNB and the number of polysulfide bonds increased with increased amounts of sulfur. DCP reacted with the double bonds in PNB to form C-C covalent bond crosslinking networks. The crosslinking mechanism revealed that the sulfur-containing cross-linked bonds, especially polysulfide bonds, were more flexible and bore large deformation, which gave the PNB excellent mechanical properties and ensured a higher shape entropy elastic recovery ratio.
Biological Inspirations: Iron Complexes Mimicking the Catechol Dioxygenases
Authors: Kałduńska Karolina , Kozakiewicz Anna , Wujak Magdalena , Wojtczak Andrzej
Published: June 2021

Within the broad group of Fe non-heme oxidases, our attention was focused on the catechol 1,2- and 2,3-dioxygenases, which catalyze the oxidative cleavage of aromatic rings. A large group of Fe complexes with N/O ligands, ranging from N3 to N2O2S, was developed to mimic the activity of these enzymes. The Fe complexes discussed in this work can mimic the intradiol/extradiol catechol dioxygenase reaction mechanism. Electronic effects of the substituents in the ligand affect the Lewis acidity of the Fe center, increasing the ability to activate dioxygen and enhancing the catalytic activity of the discussed biomimetic complexes. The ligand architecture, the geometric isomers of the complexes, and the substituent steric effects significantly affect the ability to bind the substrate in a monodentate and bidentate manner. The substrate binding mode determines the preferred mechanism and, consequently, the main conversion products. The preferred mechanism of action can also be affected by the solvents and their ability to form the stable complexes with the Fe center. The electrostatic interactions of micellar media, similar to SDS, also control the intradiol/extradiol mechanisms of the catechol conversion by discussed biomimetics.
Deterioration and Protection of Concrete Elements Embedded in Contaminated Soil: A Review
Authors: Millán Ramírez Ginneth Patricia , Byliński Hubert , Niedostatkiewicz Maciej
Published: June 2021

Coating materials are considered one of the most antique materials of human civilization; they have been used for decoration and the protection of surfaces for millennia. Concrete structures—due to their permanent exposure to different types of environments and contaminants—require the use of coatings that contribute to its preservation by reducing the corrosion of its components (steel and aggregates). This article intends to introduce the principal causes of concrete deterioration and the coating materials used to protect concrete structures, including a summary of the coating types, their advantages and disadvantages, and the latest developments and applications. Furthermore, this paper also assesses brief information about the potential challenges in the production of eco-friendly coating materials.
Effect of Heat Treatment Conditions on Corrosion Resistance of 0.28C–1.4Mn–0.3Si–0.26Cr Steel with Nb, Ti, and V Microadditions
Authors: Wojtacha Anna , Kciuk Monika , Opiela Marek
Published: June 2021

The article presents the results of the research on the influence of heat treatment conditions on corrosion resistance of newly developed HSLA-type (High Strength Low Alloy) steel in selected corrosive environments. Laboratory tests were carried out with using a salt spray chamber, enabling the continuous spraying of brine mist (5% NaCl) during 96 h under high humidity conditions. Additionally, as part of corrosion experiments, tests were carried out using the gravimetric method, in which the intensity of corrosive processes was measured by the linear corrosion rate. The research conducted revealed that the best corrosion resistance was noted for steel with a high-temperature tempered martensite microstructure. Investigated 0.28C–1.4Mn–0.3Si–0.26Cr steel with Nb, Ti, and V microadditions can be used in offshore drilling constructions and production platforms exposed to salts present in sea water, chlorides, sulfates, carbonates, and bromides, among others.
Manufacturing Elements with Small Cross-Sections of 17-4 PH Steel (1.4542) with the Application of the DMLS Additive Manufacturing Method
Authors: Budzik Grzegorz , Przeszłowski Łukasz , Dziubek Tomasz , Gontarz Małgorzata , Dębski Mariusz , Smyk Emil
Published: June 2021

The application of direct metal laser sintering renders it possible to manufacture models with complex geometries. However, there are certain limits to the application of this method connected with manufacturing thin-walled cuboidal elements, as well as cylinders and holes with small diameters. The principal objective of the research was to determine the accuracy of manufacturing geometries with small cross-sections and the possibility of application in heat exchangers that are radiators with radially arranged ribs. To that end, four specimens were designed and manufactured; their geometries of representations assumed for the purpose of research (analysis) changed dimensions within the following scope: 10–0.1 mm. The specimens to be applied in the research were manufactured with 17-4 PH stainless steel (1.4542) with the application of 3D-DMLS printing and an EOS M270 printer. The measurement of accuracy was performed with the application of an optical stereomicroscope (KERN OZL-466). In addition to that, research into the chemical composition of the material, as well as the size of spherical agglomerates, was conducted with the application of a scanning electron microscope. The analysis of the chemical composition was conducted as well (after the sintering process). The analysis of the results based on the values received by means of measurements of the manufactured geometries was divided into three parts. Based on this, it is possible to conclude that the representation of models manufactured with the application of DMLS was comparable with the assumptions, and that the deviations between a nominal dimension and that received in the course of the research were within the following scope: 0–0.1 mm. At the final stage of research and based on the received results, two heat exchangers were manufactured.
Micro-Shear Bands and Their Enhancement on High Temperature Strength of Mg-Gd-Y-Zr Alloy
Authors: Xiao Hongchao , Yang Zhengjiang , Li Jie , Wan Yingchun
Published: June 2021

When Mg-Gd-Y-Zr alloy is cold forged, a large number of nano-micro shear bands are formed inside the grains. It is observed that micro-shear bands hinder the sliding of dislocations, resulting in an increase in tensile strength at elevated temperatures. The subsequent aging treatment further strengthens the alloy. Compared with unforged aged alloys, aged samples with pre-generated micro-shear bands exhibit higher strength at room temperature to 250 °C, but exhibit similar properties at higher temperatures. Microstructure characterization and fracture behavior analysis indicate that the transformation of deformation mode from dislocation sliding to grain boundary activity is mainly due to the change of mechanical properties with temperature. In addition, the alloy precipitates with the aid of dislocations during tension, and exhibits higher strength at 200 °C than that at room temperature.
Nanocellulose Production Using Ionic Liquids with Enzymatic Pretreatment
Authors: Babicka Marta , Woźniak Magdalena , Szentner Kinga , Bartkowiak Monika , Peplińska Barbara , Dwiecki Krzysztof , Borysiak Sławomir , Ratajczak Izabela
Published: June 2021

Nanocellulose has gained increasing attention during the past decade, which is related to its unique properties and wide application. In this paper, nanocellulose samples were produced via hydrolysis with ionic liquids (1-ethyl-3-methylimidazole acetate (EmimOAc) and 1-allyl-3-methylimidazolium chloride (AmimCl)) from microcrystalline celluloses (Avicel and Whatman) subjected to enzymatic pretreatment. The obtained material was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM), and thermogravimetric analysis (TG). The results showed that the nanocellulose had a regular and spherical structure with diameters of 30–40 nm and exhibited lower crystallinity and thermal stability than the material obtained after hydrolysis with Trichoderma reesei enzymes. However, the enzyme-pretreated Avicel had a particle size of about 200 nm and a cellulose II structure. A two-step process involving enzyme pretreatment and hydrolysis with ionic liquids resulted in the production of nanocellulose. Moreover, the particle size of nanocellulose and its structure depend on the ionic liquid used.
Effect of Controlled Artificial Disorder on the Magnetic Properties of EuFe2(As1−xPx)2 Ferromagnetic Superconductor
Authors: Ghimire Sunil , Kończykowski Marcin , Cho Kyuil , Tanatar Makariy A. , Torsello Daniele , Veshchunov Ivan S. , Tamegai Tsuyoshi , Ghigo Gianluca , Prozorov Ruslan
Published: June 2021

Static (DC) and dynamic (AC, at 14 MHz and 8 GHz) magnetic susceptibilities of single crystals of a ferromagnetic superconductor, EuFe2(As1−xPx)2 (x = 0.23), were measured in pristine state and after different doses of 2.5 MeV electron or 3.5 MeV proton irradiation. The superconducting transition temperature, Tc(H), shows an extraordinarily large decrease. It starts at Tc(H=0)≈24K in the pristine sample for both AC and DC measurements, but moves to almost half of that value after moderate irradiation dose. Remarkably, after the irradiation not only Tc moves significantly below the FM transition, its values differ drastically for measurements at different frequencies, ≈16 K in AC measurements and ≈12 K in a DC regime. We attribute such a large difference in Tc to the appearance of the spontaneous internal magnetic field below the FM transition, so that the superconductivity develops directly into the mixed spontaneous vortex-antivortex state where the onset of diamagnetism is known to be frequency-dependent. We also examined the response to the applied DC magnetic fields and studied the annealing of irradiated samples, which almost completely restores the superconducting transition. Overall, our results suggest that in EuFe2(As1−xPx)2 superconductivity is affected by local-moment ferromagnetism mostly via the spontaneous internal magnetic fields induced by the FM subsystem. Another mechanism is revealed upon irradiation where magnetic defects created in ordered Eu2+ lattice act as efficient pairbreakers leading to a significant Tc reduction upon irradiation compared to other 122 compounds. On the other hand, the exchange interactions seem to be weakly screened by the superconducting phase leading to a modest increase of Tm (less than 1 K) after the irradiation drives Tc to below Tm. Our results suggest that FM and SC phases coexist microscopically in the same volume.
Effects of Gamma Radiation-Induced Crosslinking of Collagen Type I Coated Dental Titanium Implants on Osseointegration and Bone Regeneration
Authors: Cho Won-Tak , Kim So-Yeun , Jung Sung-In , Kang Seong-Soo , Kim Se-Eun , Hwang Su-Hyun , Jeong Chang-Mo , Huh Jung-Bo
Published: June 2021

This study aimed to compare two methods of crosslinking collagen type I on implanted titanium surfaces, that is, using glutaraldehyde (GA) or gamma-rays (GRs), in a beagle dog model. For in vivo experiments, implants were allocated to three groups and applied to mandibular bone defects in beagle dogs; Group SLA; non-treated Sandblasted, large grit, acid-etched (SLA) implants, Group GA; SLA implants coated with GA crosslinked collagen type I, Group GR; SLA surface implants coated with collagen type I and crosslinked using 25 kGy of 60Co gamma radiation. New bone μCT volumes were obtained, and histologic and histometric analyses were performed in regions of interest. The GR group had significantly better new bone areas (NBAs) and bone to implant contact (BIC) results than the SLA group (p < 0.05), but the GA and GR groups were similar in this respect. New bone volumes and inter-thread bone densities (ITBD) were non-significantly different in the three groups (p > 0.05). Within the limits of this study, gamma-ray collagen crosslinking on titanium implants can be considered a substitute for glutaraldehyde crosslinking.
Micro-Change Process of Calcium–Magnesium Double Expansive Agent and Its Performance Characterization in Cement-Based Materials
Authors: Ding Yihang , Mao Zhongyang , Wang Yu , Deng Min , Tang Mingshu
Published: June 2021

With the increase of cement output, the demand for cement expansion agents increases, and composite expansion agents have become the development trend. The purpose of this study is to study the microscopic change process and expansion effect of calcium oxide and magnesium oxide double expansion agents. After calcination at different temperatures, the change process of microscopic morphology of calcined products was observed. Through calcining dolomite at 900 °C, the mixture D900 of calcium oxide and magnesium oxide was obtained. To prepare mixed cement, 10 wt %, 20 wt %, and 30 wt % of D900 were added into cement to prepare mixed cement. At the same time, the compressive strength, deformation, and porosity of mixed cement were measured. The results show that adding D900 improves the expansion rate of early cement paste and reduces the compressive strength. After 120 days, the compressive strength of 20 wt % cement paste is higher than that of blank cement paste, and the porosity of 20 wt % cement paste is the lowest among the three mixed cements. This shows that 20 wt % is a more suitable substitute.
Synthesis, Surface Nitriding and Characterization of Ti-Nb Modified 316L Stainless Steel Alloy Using Powder Metallurgy
Authors: Ali Sadaqat , Irfan Muhammad , Muhammad Niazi Usama , Rani Ahmad Majdi Abdul , Shah Imran , Legutko Stanislaw , Rahman Saifur , Jalalah Mohammed , Alsaiari Mabkhoot A. , Glowacz Adam , AlKahtani Fahad Salem
Published: June 2021

The powder metallurgy (PM) technique has been widely used for producing different alloy compositions by the addition of suitable reinforcements. PM is also capable of producing desireable mechanical and physical properties of the material by varying process parameters. This research investigates the addition of titanium and niobium in a 316L stainless steel matrix for potential use in the biomedical field. The increase of sintering dwell time resulted in simultaneous sintering and surface nitriding of compositions, using nitrogen as the sintering atmosphere. The developed alloy compositions were characterized using OM, FESEM, XRD and XPS techniques for quantification of the surface nitride layer and the nitrogen absorbed during sintering. The corrosion resistance and cytotoxicity assessments of the developed compositions were carried out in artificial saliva solution and human oral fibroblast cell culture, respectively. The results indicated that the nitride layer produced during sintering increased the corrosion resistance of the alloy and the developed compositions are non-cytotoxic. This newly developed alloy composition and processing technique is expected to provide a low-cost solution to implant manufacturing.
Zn–0.8Mg–0.2Sr (wt.%) Absorbable Screws—An In-Vivo Biocompatibility and Degradation Pilot Study on a Rabbit Model
Authors: Klíma Karel , Ulmann Dan , Bartoš Martin , Španko Michal , Dušková Jaroslava , Vrbová Radka , Pinc Jan , Kubásek Jiří , Ulmannová Tereza , Foltán René , Brizman Eitan , Drahoš Milan , Beňo Michal , Čapek Jaroslav
Published: June 2021

In this pilot study, we investigated the biocompatibility and degradation rate of an extruded Zn–0.8Mg–0.2Sr (wt.%) alloy on a rabbit model. An alloy screw was implanted into one of the tibiae of New Zealand White rabbits. After 120 days, the animals were euthanized. Evaluation included clinical assessment, microCT, histological examination of implants, analyses of the adjacent bone, and assessment of zinc, magnesium, and strontium in vital organs (liver, kidneys, brain). The bone sections with the implanted screw were examined via scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). This method showed that the implant was covered by a thin layer of phosphate-based solid corrosion products with a thickness ranging between 4 and 5 µm. Only negligible changes of the implant volume and area were observed. The degradation was not connected with gas evolution. The screws were fibrointegrated, partially osseointegrated histologically. We observed no inflammatory reaction or bone resorption. Periosteal apposition and formation of new bone with a regular structure were frequently observed near the implant surface. The histological evaluation of the liver, kidneys, and brain showed no toxic changes. The levels of Zn, Mg, and Sr after 120 days in the liver, kidneys, and brain did not exceed the reference values for these elements. The alloy was safe, biocompatible, and well-tolerated.
Synthesis, Spectroscopic, and Theoretical Study of Copper and Cobalt Complexes with Dacarbazine
Authors: Świderski Grzegorz , Łaźny Ryszard , Sienkiewicz Michał , Kalinowska Monika , Świsłocka Renata , Acar Ali Osman , Golonko Aleksandra , Matejczyk Marzena , Lewandowski Włodzimierz
Published: June 2021

Dacarbazine (DAC) 5-(3,3-dimethyl-1-triazenyl)imidazole-4-carboxamide is an imidazole-carboxamide derivative that is structurally related to purines. DAC belongs to the triazene compounds, which are a group of alkylating agents with antitumor and mutagenic properties. DAC is a non-cell cycle specific drug, active in all phases of the cellular cycle. In the frame of this work the 3d metal complexes (cobalt and copper) with dacarbazine were synthesized. Their spectroscopic properties by the use of FT-IR, FT-Raman, and 1HNMR were studied. The structures of dacarbazine and its complexes with copper(II) and cobalt(II) were calculated using DFT methods. The effect of metals on the electronic charge distribution of dacarbazine was discussed on the basis of calculated NBO atomic charges. The reactivity of metal complexes in relation to ligand alone was estimated on the basis of calculated energy of HOMO and LUMO orbitals. The aromaticity of the imidazole ring in dacarbazine and the complexes were compared (on the basis of calculated geometric indices of aromaticity). Thermal stability of the investigated 3d-metal complexes with dacarbazine and the products of their thermal decomposition were analyzed.
Insights into the Microstructural Evolution Occurring during Pyrolysis of Metal-Modified Ceramers Studied through Selective SiO2 Removal
Authors: Tamayo Aitana , Rubio Juan , Rubio Fausto , Rodriguez Mᵃ Angeles
Published: June 2021

Silicon oxycarbide ceramers containing 5% aluminum, zirconium, and cobalt with respect to the total Si amount are prepared from a commercial polysiloxane and molecular precursors and pyrolyzed at temperatures ranging from 500 to 1000 °C. HF etching is carried out to partially digest the silica phase, thus revealing structural characteristics of the materials, which depend upon the incorporated heteroatom. From the structural and textural characterization, it was deduced that when Al enters into the ceramer structure, the crosslinking degree is increased, leading to lower carbon domain size and carbon incorporation as well. On the contrary, the substitution by Zr induced a phase-separated SiO2-ZrO2 network with some degree of mesoporosity even at high pyrolysis temperatures. Co, however, forms small carbidic crystallites, which strongly modifies the carbonaceous phase in such a way that even when it is added in a small amount and in combination with other heteroatoms, this transient metal dominates the structural characteristics of the ceramer material. This systematic study of the ceramer compounds allows the identification of the ultimate properties of the polymer-derived ceramic composites.
3D-Printed Barrier Membrane Using Mixture of Polycaprolactone and Beta-Tricalcium Phosphate for Regeneration of Rabbit Calvarial Defects
Authors: Lee Jun-Young , Park Jin-Young , Hong In-Pyo , Jeon Su-Hee , Cha Jae-Kook , Paik Jeong-Won , Choi Seong-Ho
Published: June 2021

Background: Polycarprolactone and beta tricalcium phosphate (PCL/β-TCP) are resorbable biomaterials that exhibit ideal mechanical properties as well as high affinity for osteogenic cells. Aim: Objective of this study was to evaluate healing and tissue reaction to the PCL/β-TCP barrier membrane in the rabbit calvaria model for guided bone regeneration. Materials and Methods: The PCL/β-TCP membranes were 3D printed. Three circular defects were created in calvaria of 10 rabbits. The three groups were randomly allocated for each specimen: (i) sham control; (ii) PCL/β-TCP membrane (PCL group); and (iii) PCL/β-TCP membrane with synthetic bone graft (PCL-BG group). The animals were euthanized after two (n = 5) and eight weeks (n = 5) for volumetric and histomorphometric analyses. Results: The greatest augmented volume was achieved by the PCL-BG group at both two and eight weeks (p < 0.01). There was a significant increase in new bone after eight weeks in the PCL group (p = 0.04). The PCL/β-TCP membrane remained intact after eight weeks with slight degradation, and showed good tissue integration. Conclusions: PCL/β-TCP membrane exhibited good biocompatibility, slow degradation, and ability to maintain space over eight weeks. The 3D-printed PCL/β-TCP membrane is a promising biomaterial that could be utilized for reconstruction of critical sized defects.
Straw-Based Activated Carbon: Optimization of the Preparation Procedure and Performance of Volatile Organic Compounds Adsorption
Authors: Li Zhen , Li Yonghong , Zhu Jiang
Published: June 2021

Straw is one of the largest agricultural biowastes and a potential alternative precursor of activated carbon. Activated carbon prepared from different types of straw have great differences in structure and adsorption performance. In order to explore the performance of different straw-based activated carbon in volatile organic compounds adsorption, five common straws were selected as potential source materials for the preparation of SAC. The straw-based activated carbons were prepared and characterized via a thermo-gravimetric analysis, scanning electron microscope and the Brunauer–Emmett–Teller method. Among the five straw-based activated carbons, millet straw-derived activated carbon exhibited superior properties in SBET, Smic and adsorption capacities of both toluene and ethyl acetate. Furthermore, the preparation process of millet straw activated carbon was optimized via response surface methodology, using carbonization temperature, carbonization time and impregnation ratio as variables and toluene adsorption capacity, ethyl acetate adsorption capacity and activated carbon yield as responses. The optimal preparation conditions include a carbonization temperature of 572 °C, carbonization time of 1.56 h and impregnation ratio (ZnCl2/PM, w/w) of 1.60, which was verified experimentally, resulting in millet straw activated carbon with a toluene adsorption capacity of 321.9 mg/g and ethyl acetate adsorption capacity of 240.4 mg/g. Meanwhile, the adsorption isothermals and regeneration performance of millet straw activated carbon prepared under the optimized conditions were evaluated. The descriptive ability of the isothermals via the Redlich–Peterson equation suggests a heterogeneous surface on millet straw activated carbon. Recyclability testing has shown that millet straw activated carbon maintained a stable adsorption capacity throughout the second to fifth cycles. The results of this work indicate that millet straw activated carbon may be a potential volatile organic compound adsorbent for industrial application.
Topological Atomic Chains on 2D Hybrid Structure
Authors: Kwapiński Tomasz , Kurzyna Marcin
Published: June 2021

Mid-gap 1D topological states and their electronic properties on different 2D hybrid structures are investigated using the tight binding Hamiltonian and the Green’s function technique. There are considered straight armchair-edge and zig-zag Su–Schrieffer–Heeger (SSH) chains coupled with real 2D electrodes which density of states (DOS) are characterized by the van Hove singularities. In this work, it is shown that such 2D substrates substantially influence topological states end evoke strong asymmetry in their on-site energetic structures, as well as essential modifications of the spectral density function (local DOS) along the chain. In the presence of the surface singularities the SSH topological state is split, or it is strongly localized and becomes dispersionless (tends to the atomic limit). Additionally, in the vicinity of the surface DOS edges this state is asymmetrical and consists of a wide bulk part together with a sharp localized peak in its local DOS structure. Different zig-zag and armachair-edge configurations of the chain show the spatial asymmetry in the chain local DOS; thus, topological edge states at both chain ends can appear for different energies. These new effects cannot be observed for ideal wide band limit electrodes but they concern 1D topological states coupled with real 2D hybrid structures.
Commercial Bone Grafts Claimed as an Alternative to Autografts: Current Trends for Clinical Applications in Orthopaedics
Authors: Govoni Marco , Vivarelli Leonardo , Mazzotta Alessandro , Stagni Cesare , Maso Alessandra , Dallari Dante
Published: June 2021

In the last twenty years, due to an increasing medical and market demand for orthopaedic implants, several grafting options have been developed. However, when alternative bone augmentation materials mimicking autografts are searched on the market, commercially available products may be grouped into three main categories: cellular bone matrices, growth factor enhanced bone grafts, and peptide enhanced xeno-hybrid bone grafts. Firstly, to obtain data for this review, the search engines Google and Bing were employed to acquire information from reports or website portfolios of important competitors in the global bone graft market. Secondly, bibliographic databases such as Medline/PubMed, Web of Science, and Scopus were also employed to analyse data from preclinical/clinical studies performed to evaluate the safety and efficacy of each product released on the market. Here, we discuss several products in terms of osteogenic/osteoinductive/osteoconductive properties, safety, efficacy, and side effects, as well as regulatory issues and costs. Although both positive and negative results were reported in clinical applications for each class of products, to date, peptide enhanced xeno-hybrid bone grafts may represent the best choice in terms of risk/benefit ratio. Nevertheless, more prospective and controlled studies are needed before approval for routine clinical use.
Structural, Thermal, and Vibrational Properties of N,N-Dimethylglycine–Chloranilic Acid—A New Co-Crystal Based on an Aliphatic Amino Acid
Authors: Hetmańczyk Joanna , Hetmańczyk Łukasz , Nowicka-Scheibe Joanna , Pawlukojć Andrzej , Maurin Jan K. , Schilf Wojciech
Published: June 2021

The new complex of N,N-Dimethylglycine (DMG) with chloranilic acid (CLA) was synthesized and examined for thermal, structural, and dynamical properties. The structure of the reaction product between DMG and CLA was investigated in a deuterated dimethyl sulfoxide (DMSO-d6) solution and in the solid state by Nuclear Magnetic Resonance (NMR) (Cross Polarization Magic Angle Spinning-CPMAS NMR). The formation of the 1:1 complex of CLA and DMG in the DMSO solution was also confirmed by diffusion measurement. X-ray single crystal diffraction results revealed that the N,N-dimethylglycine–chloranilic acid (DMG+–CLA−) complex crystallizes in the centrosymmetric triclinic P-1 space group. The X-ray diffraction and NMR spectroscopy show the presence of the protonated form of N,N-dimethylglycine and the deprotonated form of chloranilic acid molecules. The vibrational properties of the co-crystal were investigated by the use of neutron (INS), infrared (IR), and Raman (RS) spectroscopies, as well as the density functional theory (DFT) with periodic boundary conditions. From the band shape analysis of the N–CH3 bending vibration, we can conclude that the CH3 groups perform fast (τR ≈ 10−11 to 10‒13 s) reorientational motions down to a temperature of 140 K, with activation energy at ca. 6.7 kJ mol−1. X-ray diffraction and IR investigations confirm the presence of a strong N+–H···O− hydrogen bond in the studied co-crystal.
Comparison of Ni-Based Self-Fluxing Remelted Coatings for Wear and Corrosion Applications
Authors: Kazamer Norbert , Muntean Roxana , Vălean Petru Cristian , Pascal Dragoș Toader , Mărginean Gabriela , Șerban Viorel-Aurel
Published: June 2021

The present study investigates the possibility to apply a vacuum furnace thermal post-treatment as an alternative solution for flame sprayed NiCrBSi wear and corrosion-resistant coatings, deposited on a low alloyed structural steel. The controlled atmosphere offers advantages regarding the fusion of the coating, porosity reduction, and degassing. An improvement of the applied heating-cooling cycle was performed through the variation of time and temperature. The best performing samples were selected by comparing their porosity and roughness values. The chosen samples were subsequently characterized regarding their microstructure, microhardness, sliding wear, and corrosion behavior. The experimental work confirms that the use of a vacuum remelting post-process reduces the porosity below 1% and leads to the formation of a larger quantity of hard boron-containing phases, promoting a significant decrease of the wear rate, while maintaining a good corrosion behavior.
A High-Efficiency TiO2/ZnO Nano-Film with Surface Oxygen Vacancies for Dye Degradation
Authors: Ma Huizhong , Hao Baofei , Song Wentao , Guo Jinpeng , Li Mingyuan , Zhang Lan
Published: June 2021

Photocatalytic degradation of organic pollutants in water is a highly efficient and green approach. However, the low quantum efficiency is an intractable obstacle to lower the photocatalytic efficiency of photocatalysts. Herein, the TiO2/ZnO heterojunction thin films combined with surface oxygen vacancies (OVs) were prepared through magnetron sputtering, which was designed to drive rapid bulk and surface separation of charge carriers. The morphology and structural and compositional properties of films were investigated via different techniques such as SEM, XRD, Raman, AFM, and XPS. It has been found that by controlling the O2/Ar ratio, the surface morphology, thickness, chemical composition, and crystal structure can be regulated, ultimately enhancing the photocatalytic performance of the TiO2/ZnO heterostructures. In addition, the heterojunction thin film showed improved photocatalytic properties compared with the other nano-films when the outer TiO2 layer was prepared at an O2/Ar ratio of 10:35. It degraded 88.0% of Rhodamine B (RhB) in 90 min and 90.8% of RhB in 120 min. This was attributed to the heterojunction interface and surface OVs, which accelerated the separation of electron–hole (e–h) pairs.