bluuebunny/crossref_metadata_2025 huggingface dataset:
Preservice Elementary Teachers’ Mathematical Knowledge on Fractions as Operator in Word Problems
Authors: López-Martín María del Mar , Aguayo-Arriagada Carmen Gloria , García López María del Mar
Published: January 2022

The preservice primary school mathematics teacher needs training that focuses on school mathematics and its didactics. Research has shown the importance of developing mathematical content knowledge as well as adequate didactic knowledge. Teacher education programs must address both to provide an effective teaching-learning process. The present research aims to assess the mathematical content knowledge of 194 prospective teachers about fraction word problems faced by students at the Primary Education stage, based on the Mathematics Teachers′ Specialized Knowledge (MTSK) model. By means of the preservice teachers’ written answers, we explored their knowledge and identified the associated error to fraction word problems (one-step and multistep) in which the fraction has a meaning as an operator. Preservice teachers showed some difficulties when working with this content, difficulties that were intensified when they solved multistep problems. The most common error founded in both types of problems is related to the meaning of fraction as operator. The results show a weak prior mathematical content knowledge and as a consequence, it is necessary to establish preventive actions in the training degrees since an insufficient mathematical content knowledge prevents them having a proper didactic knowledge.
Knots and Knot-Hyperpaths in Hypergraphs
Authors: Rahman Saifur , Chowdhury Maitrayee , A. Firos , Cristea Irina
Published: January 2022

This paper deals with some theoretical aspects of hypergraphs related to hyperpaths and hypertrees. In ordinary graph theory, the intersecting or adjacent edges contain exactly one vertex; however, in the case of hypergraph theory, the adjacent or intersecting hyperedges may contain more than one vertex. This fact leads to the intuitive notion of knots, i.e., a collection of explicit vertices. The key idea of this manuscript lies in the introduction of the concept of the knot, which is a subset of the intersection of some intersecting hyperedges. We define knot-hyperpaths and equivalent knot-hyperpaths and study their relationships with the algebraic space continuity and the pseudo-open character of maps. Moreover, we establish a sufficient condition under which a hypergraph is a hypertree, without using the concept of the host graph.
Chaos for the Dynamics of Toeplitz Operators
Authors: Bartoll Salud , Jiménez-Munguía Ronald Richard , Martínez-Avendaño Rubén Alejandro , Peris Alfred
Published: January 2022

Chaotic properties in the dynamics of Toeplitz operators on the Hardy–Hilbert space H2(D) are studied. Based on previous results of Shkarin and Baranov and Lishanskii, a characterization of different versions of chaos formulated in terms of the coefficients of the symbol for the tridiagonal case are obtained. In addition, easily computable sufficient conditions that depend on the coefficients are found for the chaotic behavior of certain Toeplitz operators.
Rota–Baxter (Co)algebra Equation Systems and Rota–Baxter Hopf Algebras
Authors: Gu Yue , Wang Shuanhong , Ma Tianshui
Published: January 2022

We introduce and discuss the notions of Rota–Baxter bialgebra equation systems and Rota–Baxter Hopf algebras. Then we construct a lot of examples based on Hopf quasigroups.
Equilibrium in a Queueing System with Retrials
Authors: Chirkova Julia , Mazalov Vladimir , Morozov Evsey
Published: January 2022

We find an equilibrium in a single-server queueing system with retrials and strategic timing of the customers. We consider a set of customers, each of which must decide when to arrive to a queueing system during a fixed period of time. In this system, after completion of service, the server seeks a customer blocked in a virtual orbit (orbital customer) to be served next, unless a new customer captures the server. We develop, in detail, a setting with two and three customers in the set, and formulate and discuss the problem for the general case with an arbitrary number of customers. The numerical examples for the system with two and three customers included as well.
Impact of Infective Immigrants on COVID-19 Dynamics
Authors: Tchoumi Stéphane Yanick , Rwezaura Herieth , Diagne Mamadou Lamine , González-Parra Gilberto , Tchuenche Jean
Published: January 2022

The COVID-19 epidemic is an unprecedented and major social and economic challenge worldwide due to the various restrictions. Inflow of infective immigrants have not been given prominence in several mathematical and epidemiological models. To investigate the impact of imported infection on the number of deaths, cumulative infected and cumulative asymptomatic, we formulate a mathematical model with infective immigrants and considering vaccination. The basic reproduction number of the special case of the model without immigration of infective people is derived. We varied two key factors that affect the transmission of COVID-19, namely the immigration and vaccination rates. In addition, we considered two different SARS-CoV-2 transmissibilities in order to account for new more contagious variants such as Omicron. Numerical simulations using initial conditions approximating the situation in the US when the vaccination program was starting show that increasing the vaccination rate significantly improves the outcomes regarding the number of deaths, cumulative infected and cumulative asymptomatic. Other factors are the natural recovery rates of infected and asymptomatic individuals, the waning rate of the vaccine and the vaccination rate. When the immigration rate is increased significantly, the number of deaths, cumulative infected and cumulative asymptomatic increase. Consequently, accounting for the level of inflow of infective immigrants may help health policy/decision-makers to formulate policies for public health prevention programs, especially with respect to the implementation of the stringent preventive lock down measure.
A Novel Mutation in a Gene Causes Sclerosteosis in a Family of Mediterranean Origin
Authors: Ekhzaimy Aishah A. , Alyusuf Ebtihal Y. , Alswailem Meshael , Alzahrani Ali S.
Published: January 2022

Background and Objectives: Sclerostin is an SOST gene product that inhibits osteoblast activity and prevents excessive bone formation by antagonizing the Wnt signaling pathway. Sclerosteosis has been linked to loss of function mutations in the SOST gene. It is a rare autosomal recessive disorder characterized by craniotubular hyperostosis and can lead to fatal cerebellar herniation. Our aim is to describe the clinical and radiological features and the new underlying SOST mutation in a patient with sclerosteosis. Case: A 25-year-old female who was referred to the endocrine clinic for suspected excess growth hormone. The patient complained of headaches, progressive blurred vision, hearing disturbances, increased size of feet, proptosis, and protrusion of the chin. She had normal antenatal history except for syndactyly. Images showed diffuse osseous thickening and high bone mineral density. Biochemical and hormonal tests were normal. Due to progressive compressive optic neuropathy, optic nerve fenestration with decompression hemicraniotomy was performed. Sclerosteosis was suspected due to the predominant craniotubular hyperostosis with syndactyly. Using peripheral leucocyte DNA, genomic sequencing of the SOST gene was performed. This identified a novel deletion homozygous mutation in the SOST gene (c.387delG, p.Asp131ThrfsTer116) which disrupts sclerostin function, causing sclerosteosis. Conclusions: Discovery of the molecular basis of sclerosteosis represents an important advance in the diagnosis and management of this fatal disease.
Assessment of the RANTES Level Correlation and Selected Inflammatory and Pro-Angiogenic Molecules Evaluation of Their Influence on CRC Clinical Features: A Preliminary Observational Study
Authors: Mielcarska Sylwia , Kula Agnieszka , Dawidowicz Miriam , Kiczmer Paweł , Chrabańska Magdalena , Rynkiewicz Magdalena , Wziątek-Kuczmik Daria , Świętochowska Elżbieta , Waniczek Dariusz
Published: January 2022

Background and Objectives: Assessment of RANTES level and concentrations of inflammatory cytokines: programmed death ligand 1 (PD-L1), interferon gamma IFN-γ, tumor necrosis factor alpha (TNF-α), transforming growht factor β (TGF-β) (and angiogenesis factors: vascular endothelial growth factor A (VEGF-A) and vascular endothelial growth factor C (VEGF C) in tumor and margin tissues of colorectal cancer (CRC,) and evaluation of RANTES influence on histopathological parameters (microvessel density (MVD), budding, tumor-infiltrating lymphocytes (TILs)), in relation to patients’ clinical features. Materials and Methods: The study used 49 samples of tumor and margin tissues derived from CRC patients. To determinate the concentration of RANTES, PD-L1, IFN-γ, TNF-α, TGF-β, VEGF-A, and VEGF-C, we used the commercially available enzyme-linked immunosorbent assay kit. Additionally, RANTES and PD-L1 expression was assessed with the use of IHC staining in both tumor cells and TILS in randomly selected cases. MVD was assessed on CD34-stained specimens. The MVD and budding were assessed using a light microscope. Results: We found significantly higher levels of RANTES, PD-L1, IFN-γ, TNF-α, TGF-β, VEGF-A, and VEGF-C in the tumor in comparison with the margin. The RANTES tumor levels correlated significantly with those of PD-L1, TNF-α, TGF-β, VEGF-A, and VEGF-C. The RANTES margin levels were significantly associated with the margin levels of all proteins investigated—PD-L1, IFN-γ, TNF-α, TGF-β, VEGF-A, and VEGF-C. Additionally, we observed RANTES- and PD-L1-positive immunostaining in TILs. In a group of 24 specimens, 6 different CRC tumors were positive for RANTES and PD-L1 immunostaining. The IFN-gamma concentration in both tumor and margin and TGF-β in tumor correlated with TILs. TILs were negatively associated with the patients’ disease stage and N parameter. Conclusions: RANTES activity might be associated with angiogenesis, lymphogenesis, and immune escape in CRC. RANTES is an important chemokine that is a part of the chemokine–cytokine network involved in the modulation of TME composition in CRC. Further research may verify which processes are responsible for the associations observed in the study.
Left Gastric Vein Width Is an Important Risk Factor for Exacerbation of Esophageal Varices Post Balloon-Occluded Retrograde Transvenous Obliteration for Gastric Varices in Cirrhotic Patients
Authors: Mizutani Taku , Nirei Kazushige , Kanda Tatsuo , Honda Masayuki , Ishii Tomotaka , Arima Shuhei , Yamana Yoichiro , Matsumoto Naoki , Matsuoka Shunichi , Moriyama Mitsuhiko
Published: January 2022

Background and Objectives: Balloon-occluded retrograde transvenous obliteration (BRTO) could be currently one of the best therapies for patients with gastric varices. This study examined the exacerbation rates for esophageal varices following BRTO for gastric varices in patients with hepatic cirrhosis. Materials and Methods: We enrolled 91 cirrhotic patients who underwent BRTO for gastric varices. In total, 50 patients were examined for exacerbation rates of esophageal varices following BRTO. Esophageal varices and their associated exacerbation were evaluated by upper gastrointestinal endoscopy. Patients were allocated into two groups according to the main inflow tract for gastric varices: (1) 37 patients in the left gastric vein (LGV) group with an LGV width of more than 3.55 mm, and (2) 13 patients in the non-LGV group who had short gastric vein or posterior gastric vein. Moreover, treatment outcomes were retrospectively analyzed. Results: LGV width (p < 0.01) was the major risk factor for the deterioration of esophageal varices post BRTO. In addition, LGV was the most common inflow tract, and the LGV group contained 74% (37/50) of patients. The exacerbation rates of esophageal varices at 1, 2, 3, and 4 years post BRTO were 40%, 62%, 65%, and 68%, respectively. The comparison of the exacerbation rates for esophageal varices following BRTO according to inflow tract showed that the exacerbation rates were significantly higher in the LGV group than those of the non-LGV group (p = 0.03). In more than half of the subjects, LGV was the main inflow tract for gastric varices, and this group experienced more frequent exacerbations of esophageal varices following BRTO compared to patients with different inflow tract sources. Conclusion: Careful attention should be paid to the LGV width when BRTO is performed for gastric varices.
Short Term Results of Early Treatment of Developmental Dysplasia of the Hip or Luxation with Pavlik Harness in Human Position
Authors: Gahleitner Manuel , Hochgatterer Rainer , Großbötzl Gerhard , Pisecky Lorenz , Klotz Matthias , Gotterbarm Tobias , Hipmair Günter
Published: January 2022

Background and Objectives: This study shows a sufficient treatment with the Pavlik harness for all patients through all phases of developmental dysplasia of the hip (DDH) if there is a strict regime. Materials and Methods: There was an ultrasound measurement stage of IIc or worse (D, IIIa/b, IVa/b) in 159 out of 7372 newborns between 1995 and 2006 (2.15%). This is an indication for treatment with the Pavlik harness. Overall, 203 dysplastic hips were treated initially with our regime. After detection, we started the application of the Pavlik harness immediately in the ‘human position’. There were appointments every 10–14 days to check the setting combined with ultrasound controls. The treatment stopped if a mature, well-developed picture of both hips was seen when compared to Graf type Ia/b. Afterwards, an X-ray control was carried out at about one year of age. Results: 159 newborns with 203 dislocated hips were treated. The distribution following Graf’s classification was as follows: 150 type IIc (73.9%), 18 type D (8.9%), 31 type IIIa/b (15, 3%) and 4 type IV (1.9%). To summarize, there were 150 (73.9%) type IIc hips at risk of developing a dislocation but also 53 hips (26.1%) which were already dislocated at the moment of birth. There was a loss to follow-up in three patients (1.8%), and the therapy had to be changed in six cases. There was no degradation in our study population during therapy. Conclusion: The treatment with the Pavlik harness of DDH at every stage in newborns was possible and showed good results in 189 hips.
Simulation Model for Prediction of Gas Separation in Membrane Contactor Process
Authors: Yeom Choongkyun , Kim Jiwon , Park Heeyoung , Lee Jiwoong , Park Seong Eun , Gu Boram
Published: January 2022

The purpose of this study is to establish a practical simulation model based on mass balance, mass transport equations and equilibrium equation between gas and liquid phases across a porous membrane in membrane contactor process in order to predict the separation behavior by the gassing process of gas mixture in membrane contactor. The established simulation model was verified by comparison between the simulated values and real process values in the separation of CH4/CO2 mixture, showing an excellent agreement between them. The parameter R-value in the model, which is a kind of the permeability of permeant across porous membrane, has been determined by fitting a numerical solution of the model equation to the experimental data to obtain a practical value of the parameter. A parametric study on the gassing process of N2/CO2 mixture in membrane contactor was made with the help of the practical simulation model to investigate the effects of operation parameters on separation performance and to characterize the separation behavior of membrane contactor process. A series of simulations of the separation of N2/CO2 mixture in membrane contactor were conducted, and the optimization on the membrane process was discussed to maximize the separation performance in terms of N2 recovery percent in retentate and CO2 permeation rate. It was observed from the analysis of the result of the simulation that liquid flow rate has a negative effect on N2 recovery percent in retentate but a positive effect on the separation of CO2, while R-value affects the separation performance in the other way. It is confirmed in this study that the developed simulation can be used as a tool to optimize the parameters, i.e., feed gas pressure, liquid flow rate and R-value to maximize the separation performance.
ZIF-8 Nanoparticles Based Electrochemical Sensor for Non-Enzymatic Creatinine Detection
Authors: Chakraborty Titisha , Das Munmun , Lin Chan-Yu , Su Yen , Yuan Bing , Kao Chyuan-Haur
Published: January 2022

There is a consistent demand for developing highly sensitive, stable, cost-effective, and easy-to-fabricate creatinine sensors as creatinine is a reliable indicator of kidney and muscle-related disorders. Herein, we reported a highly sensitive and selective non-enzymatic electrochemical creatinine sensor via modifying poly(3,4 ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) coated indium tin oxide (ITO) substrate by zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs). The topography, crystallinity, and composition of the sensing electrode were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The peroxidase-like activity of ZIF-8 nanoparticles enabled it to detect creatinine forming a zinc-creatinine composite. The electrochemical behavior and sensing performance were evaluated by amperometric and impedimetric analysis. The sensor obtained a sufficiently low limit of detection (LOD) of 30 µM in a clinically acceptable linear range (0.05 mM–2.5 mM). The interference study demonstrated high selectivity of the sensor for creatinine concerning other similar biomolecules. The sensing performance of the creatinine sensor was verified in the actual human serum, which showed excellent recovery rates. Hence, the magnificent performance of ZIF-8 based non-enzymatic creatinine sensor validated it as a responsible entity for other complicated renal markers detection.
Effects of Cold Rolling Deformation and Solution Treatment on Microstructural, Mechanical, and Corrosion Properties of a Biocompatible Ti-Nb-Ta-Zr Alloy
Authors: Angelescu Mariana Lucia , Dan Alexandru , Ungureanu Elena , Zarnescu-Ivan Nicoleta , Galbinasu Bogdan Mihai
Published: January 2022

One of the most important requirements for a metallic biomaterial is the mechanical biocompatibility, which means excellent mechanical properties—high strength and fatigue strength, but low elastic modulus, to be mechanically harmonized with hard tissues. In order to improve the mechanical and biocompatible performance of the Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy, the influence of cold plastic deformation and solution treatment on its properties were investigated. The Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy was fabricated by melting in a cold crucible furnace (in levitation) and then subjected to several treatment schemes, which include cold rolling and different solution treatments. Microstructural and mechanical characteristics of specimens in as-cast and thermo-mechanically processed condition were determined by SEM microscopy and tensile testing, for different structural states: initial as-cast/as-received, cold rolled and solution treated at different temperatures (800, 900, and 1000 °C) and durations (5, 10, 15, and 20 min), with water quenching. It was concluded that both cold rolling and solution treatment have important positive effects on structural and mechanical properties of the biomaterial, increasing mechanical strength and decreasing the elastic modulus. Samples in different structural states were also corrosion tested and the results provided important information on determining the optimal processing scheme to obtain a high-performance biomaterial. The final processing route chosen consists of a cold rolling deformation with a total deformation degree of 60%, followed by a solution heat treatment at 900 °C with maintenance duration of 5 min and water quenching. By applying this thermo-mechanical processing scheme, the Ti-25.5Nb-4.5Ta-8.0Zr wt% alloy showed an elastic modulus of 56 GPa (5% higher than in the as-cast state), an ultimate tensile strength of 1004 MPa (41.8% higher than in the as-cast state), a yield strength of 718 MPa (40.6% higher than in the as-cast state), and increased corrosion resistance (the corrosion rate decreased by 50% compared to the as-cast state).
Gallic Acid as a Potential Green Corrosion Inhibitor for Aluminum in Acidic Solution
Authors: Kwolek Przemysław , Dychtoń Kamil , Kościelniak Barbara , Obłój Andrzej , Podborska Agnieszka , Wojnicki Marek
Published: January 2022

Plant extracts are intensively studied as green corrosion inhibitors of aluminum. Because these extracts are complex systems, the influence of their individual constituents on the corrosion of aluminum should be determined. In this work, gallic acid was tested for the first time as a corrosion inhibitor of aluminum in orthophosphoric acid aqueous solution. So far, its potential inhibiting properties in acidic solutions were only suggested based on promising results obtained for various plant extracts. Evaluation of the potential inhibiting properties of gallic acid was performed using electrochemical methods. The corrosion potential, polarization curves, and impedance spectra of aluminum in 0.5 M orthophosphoric acid, at T = 303 K, were determined. The corrosion potential, corrosion current density, and corrosion rate of aluminum in orthophosphoric acid were equal to −1.151 V vs. Ag|AgCl (3M KCl) reference electrode, 36 μA∙cm−2 and 0.39 mm∙year−1, respectively. These values did not change with the addition of gallic acid. The results obtained show that gallic acid does not inhibit aluminum corrosion. UV-Vis absorption spectra of gallic acid solutions and quantum mechanical calculations show that this organic compound did not adsorb onto the aluminum surface under the studied conditions.
Microstructure and Mechanical Properties of CoWB Based Composites Produced by Crystallization of Ni-Co-Zr-Ta-W-B Bulk Metallic Glass
Authors: Hitit Aytekin , Yazici Ziya Ozgur , Şahin Hakan , Öztürk Pelin , Eryeşil Buğrahan , Barut Nusrettin
Published: January 2022

CoWB based composites were produced by annealing Ni33.6Co23.2Zr0.5Ta4W23.7B15 bulk metallic glass above the crystallization temperature. The effect of annealing on the microstructure of the composites was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microhardness (Hv) and indentation fracture toughness (KC) of the composites were also measured. Microstructural examinations revealed that the first precipitated phase as a result of annealing is a nickel solid solution. As the annealing time is increased, CoWB and the nickel solid solution begins to precipitate. If the annealing time is increased further, the CoWB remains stable, while the nickel solid solution transforms into Ni3Ta. The microhardness of the as-cast alloy was determined to be 1190 HV. As a result of annealing, composites with a microhardness of around 1400 HV were obtained due to the precipitation of CoWB. KC of the composite with the maximum hardness was determined to be ~3 MPa.m1/2. The effect of microstructure on the mechanical properties of the composites is discussed.
Si-Al-N-O Multi-Layer Coatings with Increased Corrosion Resistance Deposited on Stainless Steel by Magnetron Sputtering
Authors: Dorofeeva Tamara , Gubaidulina Tatiana , Sergeev Victor , Fedorischeva Marina
Published: January 2022

This work studies single-layer (Al-Si-N) and multi-layer (Al-Si-N-O/Al-Si-O) coatings deposited by magnetron sputtering on stainless steel specimens (AISI 321), which can be used under aggressive conditions. The multi-layer coating consists of six alternating layers of Al-Si-N-O and Al-Si-O with a thickness of 0.9 µm and 0.2 µm, respectively. The structural-phase state and the chemical composition of the coatings were studied by transmission and scanning electron microscopy and XPS analysis. It was revealed that single-layer coatings are nanocrystalline and contain AlN and α-Si3N4 phases. Multi-layer coatings (Al-Si-N-O/Al-Si-O) are amorphous in each of the layers. The corrosion properties of substrate and coated specimens were investigated using a potentiostat in the 3.5 mg/l sea salt solution. It was found that corrosion resistance of stainless steel specimens with multi-layer coating is substantially (tenfold) higher compared with substrates and the specimens with single-layer coating.
Controllable Melting and Flow of Ag in Self-Formed Amorphous Carbonaceous Shell for Nanointerconnection
Authors: Yu Zhiqiang , Shi Qing , Wang Huaping , Shang Junyi , Huang Qiang , Fukuda Toshio
Published: January 2022

Nanointerconnection has been selected as a promising method in the post-Moore era to realize device miniaturization and integration. Even with many advances, the existing nanojoining methods still need further developments to meet the three-dimensional nanostructure construction requirements of the next-generation devices. Here, we proposed an efficient silver (Ag)-filled nanotube fabrication method and realized the controllable melting and ultrafine flow of the encapsulated silver at a subfemtogram (0.83 fg/s) level, which presents broad application prospects in the interconnection of materials in the nanometer or even subnanometer. We coated Ag nanowire with polyvinylpyrrolidone (PVP) to obtain core–shell nanostructures instead of the conventional well-established nanotube filling or direct synthesis technique, thus overcoming obstacles such as low filling rate, discontinuous metalcore, and limited filling length. Electromigration and thermal gradient force were figured out as the dominant forces for the controllable flow of molten silver. The conductive amorphous carbonaceous shell formed by pyrolyzing the insulative PVP layer was also verified by energy dispersive spectroscopy (EDS), which enabled the continued outflow of the internal Ag. Finally, a reconfigurable nanointerconnection experiment was implemented, which opens the way for interconnection error correction in the fabrication of nanoelectronic devices.
Acknowledgment to Reviewers of Microbiology Research in 2021
Authors:   Microbiology Research Editorial Office
Published: January 2022

Rigorous peer-reviews are the basis of high-quality academic publishing [...]
Biliary Diseases from the Microbiome Perspective: How Microorganisms Could Change the Approach to Benign and Malignant Diseases
Authors: Binda Cecilia , Gibiino Giulia , Coluccio Chiara , Sbrancia Monica , Dajti Elton , Sinagra Emanuele , Capurso Gabriele , Sambri Vittorio , Cucchetti Alessandro , Ercolani Giorgio , Fabbri Carlo
Published: January 2022

Recent evidence regarding microbiota is modifying the cornerstones on pathogenesis and the approaches to several gastrointestinal diseases, including biliary diseases. The burden of biliary diseases, indeed, is progressively increasing, considering that gallstone disease affects up to 20% of the European population. At the same time, neoplasms of the biliary system have an increasing incidence and poor prognosis. Framing the specific state of biliary eubiosis or dysbiosis is made difficult by the use of heterogeneous techniques and the sometimes unwarranted invasive sampling in healthy subjects. The influence of the microbial balance on the health status of the biliary tract could also account for some of the complications surrounding the post-liver-transplant phase. The aim of this extensive narrative review is to summarize the current evidence on this topic, to highlight gaps in the available evidence in order to guide further clinical research in these settings, and, eventually, to provide new tools to treat biliary lithiasis, biliopancreatic cancers, and even cholestatic disease.
Molecular Detection of Integrons, Colistin and β-lactamase Resistant Genes in Salmonella enterica Serovars Enteritidis and Typhimurium Isolated from Chickens and Rats Inhabiting Poultry Farms
Authors: Ramatla Tsepo , Mileng Kealeboga , Ndou Rendani , Mphuti Nthabiseng , Syakalima Michelo , Lekota Kgaugelo E. , Thekisoe Oriel M.M.
Published: January 2022

The rapid growth of multidrug-resistant Salmonella is a global public health concern. The aim of this study was to detect integrons, colistin and β-lactamase resistance genes in Salmonella enteritidis and typhimurium. A total of 63 isolates of S. enteritidis (n = 18) and S. typhimurium (n = 45) from fecal samples of layers and rats at chicken farms were screened for antibiotic resistant genes. Conventional PCR was performed for the detection of integrons (classes 1, 2, and 3), colistin (mcr-1-5) and β-lactamase (blaCTX-M, blaCTX-M-1, blaCTX-M-2, blaCTX-M-9, blaCTX-M-15, blaTEM, blaSHV, and blaOXA) resistant genes. Of these isolates, 77% and 27% of S. typhimurium and S. enteritidis harboured the mcr-4 encoded gene for colistin, respectively. The prevalence of class 1 integrons for S. typhimurium and S. enteritidis was 100% for each serovar, while for class 2 integrons of S. typhimurium and S. enteritidis it was 49% and 33% respectively, while class 3 integron genes was not detected. Our study also detected high levels of β-lactamase encoding genes (bla gene), namely blaCTX-M, blaCTX-M-1, blaCTX-M-9 and blaTEM from both S. typhimurium and S. enteritidis. This, to our knowledge, is the first report of mcr-4 resistance gene detection in Salmonella serovars in South Africa. This study also highlights the importance of controlling rats at poultry farms in order to reduce the risk of transmission of antibiotic resistance to chickens and eventually to humans.
Genomic Analyses of Weissella cibaria W25, a Potential Bacteriocin-Producing Strain Isolated from Pasture in Campos das Vertentes, Minas Gerais, Brazil
Authors: Teixeira Camila Gonçalves , Rodrigues Rafaela da Silva , Yamatogi Ricardo Seiti , Lucau-Danila Anca , Drider Djamel , Nero Luís Augusto , de Carvalho Antônio Fernandes
Published: January 2022

Weissella is a genus containing Gram-positive, heterofermentative bacteria belonging to the lactic acid bacteria (LAB) group. These bacteria are endowed with promising technological and antimicrobial attributes. Weissella cibaria W25 was isolated from a dairy environment where raw milk cheeses are produced. Therefore, we sequenced and assembled the W25 draft genome sequence, which consists of 41 contigs totaling ~2.4 Mbp, with a G + C content of 45.04%. Then we carried out a comprehensive comparative genomic analysis with W. cibaria 110, known to produce the weissellicin 110 bacteriocin, and four other non-bacteriocin-producing W. cibaria strains.
From Middle Neoproterozoic Extension to Paleozoic Accretion and Collision of the Eastern Tiklik Belt (the Western Kunlun Orogen, NW China)
Authors: Sang Miao , Xiao Wenjiao , Windley Brian F. , Mao Qigui , Zhang Zhiyong , Wang Hao , Yang He , Ao Songjian , Song Dongfang , Gan Jingmin , Zhang Zhixin , Li Liang
Published: January 2022

The eastern Tiklik belt is mainly composed of meta-sedimentary rocks of the Ailiankate and Sailajiazitage Groups that were previously interpreted as Palaeoproterozoic, Mesoproterozic and Neoproterozoic stratigraphic units, which are part of the Tarim Precambrian basement. Our new detrital (U-Pb) zircon ages yield a dominant single peak with a major range between ca. 700 Ma and 800 Ma for meta-sedimentary rocks from both the Ailiankate and Sailajiazitage Groups, which demonstrates that they were mainly derived from an independent Neoproterozoic terrane. There are several ages of 444–659 Ma, of which, the youngest has an age of 444 ± 6 Ma, indicating that the time of deposition of the meta-sedimentary rocks could have been in the Early Silurian. The porphyritic granite sample has a weighted mean crystallization age of 442 ± 2 Ma. The adakite-like geochemical characteristics of the porphytitic granite suggest derivation from the melting of the oceanic slab and formation in a subduction, arc-related tectonic setting. After integration with relevant published data, our work suggests that the Ailiankate and Sailajiazitage Groups belong to a tectonic mosaic that contains Middle Neoproterozoic extensional and Paleozoic accretionary and collisional complexes, rather than the Paleoproterozoic or Mesoproterozoic basement, as previously regarded. We propose a new tectonic model for the eastern Tiklik belt that started with a Middle Neoproterozoic extension and ended with Paleozoic continuous accretion and collision in a Paleo-Tethys archipelago, which contributed to the considerable continental growth of the southern Tarim Block.
Recently Discovered Secondary Metabolites from Streptomyces Species
Authors: Lacey Heather J. , Rutledge Peter J.
Published: January 2022

The Streptomyces genus has been a rich source of bioactive natural products, medicinal chemicals, and novel drug leads for three-quarters of a century. Yet studies suggest that the genus is capable of making some 150,000 more bioactive compounds than all Streptomyces secondary metabolites reported to date. Researchers around the world continue to explore this enormous potential using a range of strategies including modification of culture conditions, bioinformatics and genome mining, heterologous expression, and other approaches to cryptic biosynthetic gene cluster activation. Our survey of the recent literature, with a particular focus on the year 2020, brings together more than 70 novel secondary metabolites from Streptomyces species, which are discussed in this review. This diverse array includes cyclic and linear peptides, peptide derivatives, polyketides, terpenoids, polyaromatics, macrocycles, and furans, the isolation, chemical structures, and bioactivity of which are appraised. The discovery of these many different compounds demonstrates the continued potential of Streptomyces as a source of new and interesting natural products and contributes further important pieces to the mostly unfinished puzzle of Earth’s myriad microbes and their multifaceted chemical output.
Guggulsterone Mediated JAK/STAT and PPAR-Gamma Modulation Prevents Neurobehavioral and Neurochemical Abnormalities in Propionic Acid-Induced Experimental Model of Autism
Authors: Khera Rishabh , Mehan Sidharth , Bhalla Sonalika , Kumar Sumit , Alshammari Abdulrahman , Alharbi Metab , Sadhu Satya Sai
Published: January 2022

Autism spectrum disorder is a neurodevelopmental disorder marked by repetitive behaviour, challenges in verbal and non-verbal communication, poor socio-emotional health, and cognitive impairment. An increased level of signal transducer and activator of transcription 3 (STAT3) and a decreased level of peroxisome proliferator-activated receptor (PPAR) gamma have been linked to autism pathogenesis. Guggulsterone (GST) has a neuroprotective effect on autistic conditions by modulating these signalling pathways. Consequently, the primary objective of this study was to examine potential neuroprotective properties of GST by modulating JAK/STAT and PPAR-gamma levels in intracerebroventricular propionic acid (ICV PPA) induced experimental model of autism in adult rats. In this study, the first 11 days of ICV-PPA injections in rats resulted in autism-like behavioural, neurochemical, morphological, and histopathological changes. The above modifications were also observed in various biological samples, including brain homogenate, CSF, and blood plasma. GST was also observed to improve autism-like behavioural impairments in autistic rats treated with PPA, including locomotion, neuromuscular coordination, depression-like behaviour, spatial memory, cognition, and body weight. Prolonged GST treatment also restored neurochemical deficits in a dose-dependent manner. Chronic PPA administration increased STAT3 and decreased PPAR gamma in autistic rat brain, CSF, and blood plasma samples, which were reversed by GST. GST also restored the gross and histopathological alterations in PPA-treated rat brains. Our results indicate the neuroprotective effects of GST in preventing autism-related behavioural and neurochemical alterations.
A New Protocol for Ash Wood Modification: Synthesis of Hydrophobic and Antibacterial Brushes from the Wood Surface
Authors: Macior Angelika , Zaborniak Izabela , Chmielarz Paweł , Smenda Joanna , Wolski Karol , Ciszkowicz Ewa , Lecka-Szlachta Katarzyna
Published: January 2022

The article presents the modification of ash wood via surface initiated activators regenerated by electron transfer atom transfer radical polymerization mediated by elemental silver (Ag0 SI-ARGET ATRP) at a diminished catalyst concentration. Ash wood is functionalized with poly(methyl methacrylate) (PMMA) and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) to yield wood grafted with PMMA-b-PDMAEMA-Br copolymers with hydrophobic and antibacterial properties. Fourier transform infrared (FT-IR) spectroscopy confirmed the covalent incorporation of functional ATRP initiation sites and polymer chains into the wood structure. The polymerization kinetics was followed by the analysis of the polymer grown in solution from the sacrificial initiator by proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The polymer layer covalently attached to the wood surface was observed by scanning electron microscopy (SEM). The hydrophobic properties of hybrid materials were confirmed by water contact angle measurements. Water and sodium chloride salt aqueous solution uptake tests confirmed a significant improvement in resistance to the absorption of wood samples after modification with polymers. Antibacterial tests revealed that wood-QPDMAEMA-Br, as well as wood-PMMA-b-QPDMAEMA-Br, exhibited higher antibacterial activity against Gram-positive bacteria (Staphylococcus aureus) in comparison with Gram-negative bacteria (Escherichia coli). The paper presents an economic concept with ecological aspects of improving wood properties, which gives great opportunities to use the proposed approach in the production of functional hybrid materials for industry and high quality sports equipment, and in furniture production.
Spin Orbit Coupling in Orthogonal Charge Transfer States: (TD-)DFT of Pyrene—Dimethylaniline
Authors: Bissesar Shivan , van Raamsdonk Davita M. E. , Gibbons Dáire J. , Williams René M.
Published: January 2022

The conformational dependence of the matrix element for spin–orbit coupling and of the electronic coupling for charge separation are determined for an electron donor–acceptor system containing a pyrene acceptor and a dimethylaniline donor. Different kinetic and energetic aspects that play a role in the spin–orbit charge transfer intersystem crossing (SOCT-ISC) mechanism are discussed. This includes parameters related to initial charge separation and the charge recombination pathways using the Classical Marcus Theory of electron transfer. The spin–orbit coupling, which plays a significant role in charge recombination to the triplet state, can be probed by (TD)-DFT, using the latter as a tool to understand and predict the SOCT-ISC mechanism. The matrix elements for spin–orbit coupling for acetone and 4-thio-thymine are used for benchmarking. (Time Dependent-) Density Functional Theory (DFT and TD-DFT) calculations are applied using the quantum chemical program Amsterdam Density Functional (ADF).
Characterization of Labeled Gold Nanoparticles for Surface-Enhanced Raman Scattering
Authors: Aldosari Fahad M. M.
Published: January 2022

Noble metal nanoparticles (NP) such as gold (AuNPs) and silver nanoparticles (AgNPs) can produce ultrasensitive surface-enhanced Raman scattering (SERS) signals owing to their plasmonic properties. AuNPs have been widely investigated for their biocompatibility and potential to be used in clinical diagnostics and therapeutics or combined for theranostics. In this work, labeled AuNPs in suspension were characterized in terms of size dependency of their localized surface plasmon resonance (LSPR), dynamic light scattering (DLS), and SERS activity. The study was conducted using a set of four Raman labels or reporters, i.e., small molecules with large scattering cross-section and a thiol moiety for chemisorption on the AuNP, namely 4-mercaptobenzoic acid (4-MBA), 2-naphthalenethiol (2-NT), 4-acetamidothiophenol (4-AATP), and biphenyl-4-thiol (BPT), to investigate their viability for SERS tagging of spherical AuNPs of different size in the range 5 nm to 100 nm. The results showed that, when using 785 nm laser excitation, the SERS signal increases with the increasing size of AuNP up to 60 or 80 nm. The signal is highest for BPT labelled 80 nm AuNPs followed by 4-AATP labeled 60 nm AuNPs, making BPT and 4-AATP the preferred candidates for Raman labelling of spherical gold within the range of 5 nm to 100 nm in diameter.
Applicability of Ash Wastes for Reducing Trace Element Content in Zea mays L. Grown in Eco-Diesel Contaminated Soil
Authors: Wyszkowski Mirosław , Wyszkowska Jadwiga , Kordala Natalia , Borowik Agata
Published: January 2022

Among the large group of xenobiotics released into the environment, petroleum derivatives are particularly dangerous, especially given continuing industrial development and the rising demand for fuel. As increasing amounts of fly ash and sewage sludge are released, it becomes necessary to explore new methods of reusing these types of waste as reclamation agents or nutrient sources. The present study examined how soil contamination with Eco-Diesel oil (0; 10; 20 cm3 kg−1 soil) affected the trace-element content in the aerial parts of maize. Coal and sludge ashes were used as reclamation agents. Our study revealed that diesel oil strongly affected the trace-element content in the aerial parts of maize. In the non-amended group, Eco-Diesel oil contamination led to higher accumulation of the trace elements in maize (with the exception of Pb and Ni), with Cu and Mn content increasing the most. The ashes incorporated into the soil performed inconsistently as a reclamation agent. Overall, the amendment reduced Mn and Fe in the aerial parts of maize while increasing average Cd and Cu levels. No significant effect was noted for the other elements.
Investigating the Role of Obesity in Prostate Cancer and Identifying Biomarkers for Drug Discovery: Systems Biology and Deep Learning Approaches
Authors: Yeh Shan-Ju , Chung Yun-Chen , Chen Bor-Sen
Published: January 2022

Prostate cancer (PCa) is the second most frequently diagnosed cancer for men and is viewed as the fifth leading cause of death worldwide. The body mass index (BMI) is taken as a vital criterion to elucidate the association between obesity and PCa. In this study, systematic methods are employed to investigate how obesity influences the noncutaneous malignancies of PCa. By comparing the core signaling pathways of lean and obese patients with PCa, we are able to investigate the relationships between obesity and pathogenic mechanisms and identify significant biomarkers as drug targets for drug discovery. Regarding drug design specifications, we take drug–target interaction, drug regulation ability, and drug toxicity into account. One deep neural network (DNN)-based drug–target interaction (DTI) model is trained in advance for predicting drug candidates based on the identified biomarkers. In terms of the application of the DNN-based DTI model and the consideration of drug design specifications, we suggest two potential multiple-molecule drugs to prevent PCa (covering lean and obese PCa) and obesity-specific PCa, respectively. The proposed multiple-molecule drugs (apigenin, digoxin, and orlistat) not only help to prevent PCa, suppressing malignant metastasis, but also result in lower production of fatty acids and cholesterol, especially for obesity-specific PCa.
Medicine-Food Herbs against Alzheimer’s Disease: A Review of Their Traditional Functional Features, Substance Basis, Clinical Practices and Mechanisms of Action
Authors: Guo Pengfei , Zhang Baoyue , Zhao Jun , Wang Chao , Wang Zhe , Liu Ailin , Du Guanhua
Published: January 2022

Alzheimer’s disease (AD) is a progressive, neurodegenerative disorder that currently has reached epidemic proportions among elderly populations around the world. In China, available traditional Chinese medicines (TCMs) that organically combine functional foods with medicinal values are named “Medicine Food Homology (MFH)”. In this review, we focused on MFH varieties for their traditional functional features, substance bases, clinical uses, and mechanisms of action (MOAs) for AD prevention and treatment. We consider the antiAD active constituents from MFH species, their effects on in vitro/in vivo AD models, and their drug targets and signal pathways by summing up the literature via a systematic electronic search (SciFinder, PubMed, and Web of Science). In this paper, several MFH plant sources are discussed in detail from in vitro/in vivo models and methods, to MOAs. We found that most of the MFH varieties exert neuroprotective effects and ameliorate cognitive impairments by inhibiting neuropathological signs (Aβ-induced toxicity, amyloid precursor protein, and phosphorylated Tau immunoreactivity), including anti-inflammation, antioxidative stress, antiautophagy, and antiapoptosis, etc. Indeed, some MFH substances and their related phytochemicals have a broad spectrum of activities, so they are superior to simple single-target drugs in treating chronic diseases. This review can provide significant guidance for people’s healthy lifestyles and drug development for AD prevention and treatment.
Screening Wild Yeast Isolated from Cocoa Bean Fermentation Using Volatile Compounds Profile
Authors: Sandoval-Lozano Claudia Johanna , Caballero-Torres David , López-Giraldo Luis Javier
Published: January 2022

Yeasts are one of the main ingredients responsible for flavor precursors production associated with sensorial characteristics in chocolate. Using wild yeast isolated from cocoa beans fermentation is emerging as a strategy for developing starter cultures. However, the volatile compounds (VCs) produced by yeasts are not yet known. This study aimed to select wild yeasts with the potential to produce volatile compounds associated with desirable flavor attributes. A total of 150 wild yeasts strains were isolated from the spontaneous cocoa beans fermentation, of which 40 were identified by morphology and physiological features. VCs produced were identified and quantified using SPME-GC-MS and GC-FID and profiles were evaluated statistically by PCA and cluster analysis for the compounds that had a high odor threshold value. Thirty-six VCs produced by these yeasts were identified into six main families, namely esters, alcohols, acids, aldehydes, ketones, and pyrazines. PCA showed the separation of the yeasts into two main clusters. Strains, Y195 and Y246, belong to the first cluster and are the highest producers of alcohols related to floral perceptions. In the second cluster, thirty-three yeasts were grouped by their ability to produce esters. Of all of them, Y110MRS stood out for producing 2-phenyl ethyl acetate and isoamyl acetate associated with fruity perceptions. This screening allowed us to identify yeasts that produced VCs of technological interest and which could be used to develop a starter culture.