bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Toxicological In Vitro and In Ovo Screening of Different Orthodontic Implants Currently Used in Dentistry
Authors: Szuhanek Camelia A. , Watz Claudia G. , Avram Ștefana , Moacă Elena-Alina , Mihali Ciprian V. , Popa Adelina , Campan Andrada A. , Nicolov Mirela , Dehelean Cristina A.
Published: December 2020

Selecting the most biocompatible orthodontic implant available on the market may be a major challenge, given the wide array of orthodontic devices currently available on the market. The latest scientific data have suggested that in vitro evaluations using oral cell lines provide reliable data regarding the toxicity of residual particles released by different types of orthodontic devices. In this regard, the in vitro biocompatibility of three different commercially available implants (stainless steel and titanium-based implants) was assessed. Methods: As an in vitro model, human gingival fibroblasts (HGFs) were employed to evaluate the cellular morphology, cell viability, and cytotoxicity by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays at 24 h and 72 h post-exposure to test implants. Results: The results correlate the composition and topography of the implant surface with biological experimental evaluations related to directly affected cells (gingival fibroblasts) and toxicological results on blood vessels (hen’s egg test-chorioallantoic membrane (HET-CAM) assay). The stainless steel implant exhibits a relative cytotoxicity against HGF cells, while the other two samples induced no significant alterations of HGF cells. Conclusion: Among the three test orthodontic implants, the stainless steel implant induced slight cytotoxic effects, thus increased vigilance is required in their clinical use, especially in patients with high sensitivity to nickel.
Fabrication of Anti-Reflective Surface with Superhydrophobicity/High Oleophobicity and Enhanced Mechanical Durability via Nanosecond Laser Surface Texturing
Authors: Wang Huixin , Zhuang Jian , Yu Jiangtao , Qi Hongyan , Ma Yunhai , Wang Hubiao , Guo Zhijun
Published: December 2020

In this work, anti-reflective surface with superhydrophobicity/oleophobicity and enhanced abrasion resistance was fabricated on steel alloy surface. Two different surface patterns (i.e., parallel microgrooves and spot arrays) were created by nanosecond laser ablation and chemical immersion. The surface micro/nanostructure, spectral reflectance, wettability, and abrasion resistance of all the samples were determined. The experimental results showed that the laser-chemical treated surfaces exhibited much lower spectral reflectance and significantly enhanced surface integrities compared with the untreated surface. Firstly, the contact angles of water, glycerol, and engine oil on the laser-chemical treated surfaces were increased up to 158.9°, 157.2°, and 130.0° respectively, meaning the laser-chemical treated surfaces achieved both superhydrophobicity and high oleophobicity. Secondly, the laser-chemical treated surface showed enhanced abrasion resistance. The experimental results indicated that the spectral reflectance of the laser-chemical treated surfaces remained almost unchanged, while the laser-chemical treated surface patterned with parallel microgrooves sustained superhydrophobicity with a water contact angle of 150.2° even after more than one hundred abrasion cycles, demonstrating the superior mechanical durability. Overall, this fabrication method has shown its effectiveness for fabrication of multifunctional metal surface integrating the surface functionalities of anti-reflectivity, superhydrophobicity/high oleophobicity, and enhanced abrasion resistance.
Analysis of Long-Term Impact of Maintenance Policy on Maintenance Capacity Using a Time-Driven Activity-Based Life-Cycle Costing
Authors: Durán Orlando , Afonso Paulo , Minatogawa Vinicius
Published: December 2020

In capital-intensive industries, physical assets and maintenance activities play a relevant and strategic role in terms of providing operational continuity and business sustainability. As a result, maintenance support structures are highly complex and sophisticated. Therefore, maintenance capacity planning must be addressed using reliable techniques to assure the adequate service levels and availabilities of critical assets at the minimum opportunity cost. There has been relatively limited research on how to determine and optimize the maintenance support structure (human resources) in such organizations. This paper proposes a novel technique for dimensioning and optimizing maintenance capacity that combines Time-Driven Activity-Based Costing and Life-Cycle Costing with the Weibull function-based reliability model. Following the main principles of the Design Science Research we propose a sophisticated but simple artifact. Through this model, it is possible to compute maintenance costs and assess both used and idle capacities, considering the behavior over time of the failure rates and the reliability of critical assets within a plant. To demonstrate how the proposed methodology addresses the problem, the model was applied in a real medium-sized Chilean comminution plant and a sensitivity analysis was performed, particularly, to evaluate the relevance of appropriate maintenance workforce planning.
Using Parameter Elimination to Solve Discrete Linear Chebyshev Approximation Problems
Authors: Krivulin Nikolai
Published: December 2020

We consider discrete linear Chebyshev approximation problems in which the unknown parameters of linear function are fitted by minimizing the least maximum absolute deviation of errors. Such problems find application in the solution of overdetermined systems of linear equations that appear in many practical contexts. The least maximum absolute deviation estimator is used in regression analysis in statistics when the distribution of errors has bounded support. To derive a direct solution of the problem, we propose an algebraic approach based on a parameter elimination technique. As a key component of the approach, an elimination lemma is proved to handle the problem by reducing it to a problem with one parameter eliminated, together with a box constraint imposed on this parameter. We demonstrate the application of the lemma to the direct solution of linear regression problems with one and two parameters. We develop a procedure to solve multidimensional approximation (multiple linear regression) problems in a finite number of steps. The procedure follows a method that comprises two phases: backward elimination and forward substitution of parameters. We describe the main components of the procedure and estimate its computational complexity. We implement symbolic computations in MATLAB to obtain exact solutions for two numerical examples.
Incorporating Outsourcing Strategy and Quality Assurance into a Multiproduct Manufacturer–Retailer Coordination Replenishing Decision
Authors: Chiu Yuan-Shyi Peter , Chiu Victoria , Yeh Tsu-Ming , Wu Hua-Yao
Published: December 2020

This study explores the multiproduct manufacturer-retailer coordination replenishing decision featuring outsourcing strategy and product quality assurance. Globalization has generated enormous opportunities. Consequently, transnational firms now face tough competition in global markets. To stay competitive, a firm should meet the client’s multi-item and quality requirements under capacity constraints and optimize the intra-supply chain system to allow the timely distribution of finished goods under minimum system cost. The outsourcing option is considered to release machine loadings and reduce cycle time effectively. All items fabricated are screened for quality, and reworkable and scrap items are separated. Any reworked items that fail the quality reassurance screening are discarded, whereas all outsourced products are quality-guaranteed by the provider. A fixed-quantity multi-shipment plan is used when the whole finished lot is quality-ensured to help present-day transnational firms gain competitive advantage by making efficient and cost-effective multiproduct manufacturing and delivering decisions. Mathematical modeling is built to portray the system’s characteristics, and conventional differential calculus is used to solve and derive the optimal operating policy for the proposed problem. Simultaneously, we find the optimal delivery frequency and common cycle time for the problem mentioned above. A simulated numerical example and sensitivity analysis demonstrate the research result’s capability and applicability. Our precise analytical model can reveal/highlight the impact of deviations in quality- and outsourcing-related features on the optimal operating policy and several performance indicators that help managerial decision-making.
Assessing Blockchain Investments through the Learning Option: An Application to the Automotive and Aerospace Industry
Authors: Sánchez Pérez Ana María , Tarifa Fernández Jorge , Cruz Rambaud Salvador
Published: December 2020

Blockchain technology has demonstrated huge potential in providing simplicity and efficiency for different industries. However, its implementation in the automotive and aerospace industry is quite slow because of its difficulty to show value creation. Real option methodology, specifically the learning option, is an assessment tool which fits the conditions under which investment in blockchain technology is carried out. Thus, its application can help managers to wisely invest in this technology despite the complexity of this industry. This study offers a suitable tool to assess the strategic value of an investment in blockchain technology from a conservative position by using the real option approach, particularly the learning option. Specifically, this paper provides the mathematical expression to obtain the value of a project which includes the learning option for n periods. Likewise, it tries to raise awareness among managers of the importance to gather relevant information before making irreversible decisions. The results show that, despite the high profitability of the analyzed sector and the strategic value added by the learning option to the investment, the value of this option remains constant over the project lifespan. This indicates that the blockchain investment has to be implemented as soon as possible given that it is a highly profitable project whose value increases very slowly by waiting to get more new information. In this way, the immediate investment in blockchain technology in the automotive and aerospace industry is recommended to reap the competitive advantages offered by digital technologies.
Ethical Challenges in Health Care Policy during COVID-19 Pandemic in Italy
Authors: Ferorelli Davide , Mandarelli Gabriele , Solarino Biagio
Published: December 2020

Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, Italy has proven to be one of the countries with the highest coronavirus-linked death rate. To reduce the impact of SARS-CoV-2 coronavirus, the Italian Government decision-makers issued a series of law decrees that imposed measures limiting social contacts, stopped non-essential production activities, and restructured public health care in order to privilege assistance to patients infected with SARS-CoV-2. Health care services were substantially limited including planned hospitalization and elective surgeries. These substantial measures were criticized due to their impact on individual rights including freedom and autonomy, but were justified by the awareness that hospitals would have been unable to cope with the surge of infected people who needed treatment for COVID-19. The imbalance between the need to guarantee ordinary care and to deal with the pandemic, in a context of limited health resources, raises ethical concerns as well as clinical management issues. The emergency scenario caused by the COVID-19 pandemic, especially in the lockdown phase, led the Government and health care decision-makers to prioritize community safety above the individuals’ rights. This new community-centered approach to clinical care has created tension among the practitioners and exposed health workers to malpractice claims. Reducing the morbidity and mortality rates of the COVID-19 pandemic is the priority of every government, but the legitimate question remains whether the policy that supports this measure could be less harmful for the health care system.
Contrast-Enhanced Ultrasound (CEUS) for the Evaluation of Bosniak III Complex Renal Cystic Lesions—A 10-Year Specialized European Single-Center Experience with Histopathological Validation
Authors: Schwarze Vincent , Rübenthaler Johannes , Čečatka Saša , Marschner Constantin , Froelich Matthias Frank , Sabel Bastian Oliver , Staehler Michael , Knösel Thomas , Geyer Thomas , Clevert Dirk-André
Published: December 2020

Background and objectives: The aim of the present retrospective single-center study is to evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) for assessing Bosniak III complex renal cystic lesions with histopathological validation. Materials and Methods: 49 patients with CEUS-categorized Bosniak III renal cystic lesions were included in this retrospective study. All patients underwent native B-mode, Color Doppler, contrast-enhanced ultrasound (CEUS) between 2010–2020. Eight and five patients underwent computed tomography (CT) and magnetic resonance imaging (MRI), respectively. Twenty-nine underwent (partial) nephrectomy allowing for histopathological analysis. The applied contrast agent for CEUS was a second-generation blood pool agent. Ultrasonography examinations were performed and interpreted by a single experienced radiologist with more than 15 years of experience (EFSUMB Level 3). Results: CEUS examinations were successfully performed in all included patients without registering any adverse effects. The malignancy rate of CEUS-categorized Bosniak III renal lesions accounted for 66%. Initially, cystic complexity was visualized in native B-mode. In none of the renal lesions hypervascularization was detected in Color Doppler. CEUS allowed for detection of contrast enhancement patterns in all included Bosniak III renal lesions. Delayed wash-out could be detected in 6/29 renal lesions. In two cases of histopathologically confirmed clear-cell RCC, appropriate up-grading from Bosniak IIF to III was achieved by CEUS. Conclusions: CEUS depicts a promising imaging modality for the precise diagnostic workup and stratification of renal cystic lesions according to the Bosniak classification system, thereby helping guidance of adequate clinical management in the future.
Assessment of the Relationship between Mortality and Troponin I Levels in Hospitalized Patients with the Novel Coronavirus (COVID-19)
Authors: Özyılmaz Sinem , Ergün Alış Esra , Ermiş Emrah , Allahverdiyev Samir , Uçar Hakan
Published: December 2020

Background and Objectives: This study aimed to evaluate the relationship between mortality and cardiac laboratory findings in patients who were hospitalized after a positive PCR for COVID-19 infection. Materials and Methods: This study included patients who were admitted to or referred to the hospital between 20 March and 20 June 2020, diagnosed with COVID-19 via a positive RT-PCR from nasal and pharyngeal swab samples. The troponin I level was measured from each patient. Medical records of patients were retrospectively reviewed and analyzed. Results: A hundred and five patients who were diagnosed with COVID-19 and hospitalized, or who died in the hospital due to COVID-19, were included in this study. There was a statistically significant difference between the troponin I high and low level groups in terms of age (years), BMI, shortness of breath (SB), oxygen saturation (%), hypertension, length of stay in the ICU; and for mortality, C-reactive protein, the neutrophil-to-lymphocyte ratio, hemoglobin, lactate dehydrogenase, ferritin, D-dimer, creatine kinase-MB, prothrombin time, calcium, and 25-hydroxy vitamin 25(OH)D3 (all p < 0.05). In the logistic analyses, a significant association was noted between troponin I and the adjusted risk of mortality. A ROC curve analysis identified troponin I values > 7.8 pg/mL as an effective cut-off point in mortality for patients with COVID-19. A troponin I value of higher than 7.8 pg/mL yielded a sensitivity of 78% and a specificity of 86%. Conclusions: The hospital mortality rate was higher among patients diagnosed with COVID-19 accompanied by troponin levels higher than 7.8 pg/mL. Therefore, in patients diagnosed with COVID-19, elevated troponin I levels >7.8 pg/mL can be considered an independent risk factor for mortality.
Chemotherapy Drugs Based on Solid Lipid Nanoparticles for Breast Cancer Treatment
Authors: Ashtari Atefeh , Niazvand Firoozeh , Khorsandi Layasadat
Published: December 2020

Cancer is a group of diseases that include uncontrolled cell division and cell migration, as well as resistance to cell death [...]
Graphene Oxide Incorporated Polysulfone Substrate for Flat Sheet Thin Film Nanocomposite Pressure Retarded Osmosis Membrane
Authors: Idris Siti Nur Amirah , Jullok Nora , Lau Woei Jye , Ong Hui Lin , Dong Cheng-Di
Published: December 2020

This study focuses on the development of flat sheet thin film nanocomposite (TFN) pressure retarded osmosis (PRO) membranes for the enhancement of osmotic power generation by the incorporation of laboratory-synthesised graphene oxide (GO) into the polysulfone (PSf) polymer matrix. A series of membranes containing different weight percent of GO (0, 0.1, 0.25, 0.5 and 1.0 wt%) were fabricated via a phase inversion method with polyethylene glycol (PEG) as the pore forming agent. The results show that the TFN-0.25GO membrane has excellent water flux, salt reverse flux, high porosity and an enhanced microvoids morphology compared to the control membrane. The highest power density was achieved when TFN-0.25GO was used is 8.36 Wm−2 at pressure >15 bar. It was found that the incorporation of GO into the polymer matrix has significantly improved the intrinsic and mechanical properties of the membrane.
Improvement of Component Flux Estimating Model for Pervaporation Processes
Authors: Szilagyi Botond , Toth Andras Jozsef
Published: December 2020

Separating non-ideal mixtures by pervaporation (hence PV) is a competitive alternative to most traditional methods, such as distillation, which are based on the vapour–liquid equilibrium (VLE). It must be said, in many cases, accurate VLE data are already well known in the literature. They make the method of PV modelling a lot more complicated, and most of the viable models are (semi)empirical and focus on component flux (Ji) estimation. The pervaporation model of Mizsey and Valentinyi, which is based on Rautenbach’s works, is further improved in this work and tested rigorously by statistical means. Until now, this type of exponential modelling was only used for alcohol–water mixtures, but in this work, it was extended to an ethyl acetate–water binary mixture as well. Furthermore, a flowchart of modelling is presented for the first time in the case of an exponential pervaporation model. The results of laboratory-scale experiments were used as the basis of the study and least squares approximation was used to compare them to the different model’s estimations. According to our results, Valentinyi’s model (Model I) and the alternative model (Model III) appear to be the best methods for PV modelling, and there is no significant difference between the models, mainly in organophilic cases. In the case of the permeation component, Model I, which better follows the exponential function, is recommended. It is important to emphasize that our research confirms that the exponential type model seems to be universally feasible for most organic–water binary mixtures. Another novelty of the work is that after PDMS and PVA-based membranes, the accuracy of the semiempirical model for the description of water flux on a PEBA-based membrane was also proved, in the organophilic case.
Catalytic Degradability of p-Nitrophenol Using Ecofriendly Silver Nanoparticles
Authors: Shimoga Ganesh , Palem Ramasubba Reddy , Lee Soo-Hong , Kim Sang-Youn
Published: December 2020

In an effort to produce non-toxic and economically viable “green” protocols for waste water treatment, researchers are actively involved to develop versatile and effective silver nanoparticles (SNPs) as nano-catalyst from bio-based techniques. Since, p-nitrophenol (PNP) is one of the anthropogenic contaminants, considerable attention has been focused in catalytic degradability of PNP in wastewater treatment by curtailing serious effect on aquatic fauna. Ingestion of contaminants by aquatic organisms will not only affect the aquatic species but is also a potential threat to human health, especially if the toxic contaminants are involved in food chain. In this short report, we provided a comprehensive insight on few remarkable nanocatalysts especially based on SNPs and its biopolymer composites synthesized via ecofriendly “green” route. The beneficiality and catalytic performance of these silver nanocatalysts are concisely documented on standard model degradation reduction of PNP to p-aminophenol (PAP) in the presence of aqueous sodium borohydride. The catalytic degradation of PNP to PAP using SNPs follows pseudo first order kinetics involving six-electrons with lower activation energy. Furthermore, we provided a list of highly effective, recoverable, and economically viable SNPs, which demonstrated its potential as nanocatalysts by focusing its technical impact in the area of water remediation.
Integration of Lipidomics and Transcriptomics Reveals Reprogramming of the Lipid Metabolism and Composition in Clear Cell Renal Cell Carcinoma
Authors: Lucarelli Giuseppe , Ferro Matteo , Loizzo Davide , Bianchi Cristina , Terracciano Daniela , Cantiello Francesco , Bell Lauren N. , Battaglia Stefano , Porta Camillo , Gernone Angela , Perego Roberto A. , Maiorano Eugenio , de Cobelli Ottavio , Castellano Giuseppe , Vincenti Leonardo , Ditonno Pasquale , Battaglia Michele
Published: December 2020

Clear cell renal cell carcinoma (ccRCC) is fundamentally a metabolic disease. Given the importance of lipids in many cellular processes, in this study we delineated a lipidomic profile of human ccRCC and integrated it with transcriptomic data to connect the variations in cancer lipid metabolism with gene expression changes. Untargeted lipidomic analysis was performed on 20 ccRCC and 20 paired normal tissues, using LC-MS and GC-MS. Different lipid classes were altered in cancer compared to normal tissue. Among the long chain fatty acids (LCFAs), significant accumulations of polyunsaturated fatty acids (PUFAs) were found. Integrated lipidomic and transcriptomic analysis showed that fatty acid desaturation and elongation pathways were enriched in neoplastic tissue. Consistent with these findings, we observed increased expression of stearoyl-CoA desaturase (SCD1) and FA elongase 2 and 5 in ccRCC. Primary renal cancer cells treated with a small molecule SCD1 inhibitor (A939572) proliferated at a slower rate than untreated cancer cells. In addition, after cisplatin treatment, the death rate of tumor cells treated with A939572 was significantly greater than that of untreated cancer cells. In conclusion, our findings delineate a ccRCC lipidomic signature and showed that SCD1 inhibition significantly reduced cancer cell proliferation and increased cisplatin sensitivity, suggesting that this pathway can be involved in ccRCC chemotherapy resistance.
Marine Bacteria Display Different Escape Mechanisms When Facing Their Protozoan Predators
Authors: Guillonneau Richard , Baraquet Claudine , Molmeret Maëlle
Published: December 2020

Free-living amoeba are members of microbial communities such as biofilms in terrestrial, fresh, and marine habitats. Although they are known to live in close association with bacteria in many ecosystems such as biofilms, they are considered to be major bacterial predators in many ecosystems. Little is known on the relationship between protozoa and marine bacteria in microbial communities, more precisely on how bacteria are able survive in environmental niches where these bacterial grazers also live. The objective of this work is to study the interaction between the axenized ubiquitous amoeba Acanthamoeba castellanii and four marine bacteria isolated from immersed biofilm, in order to evaluate if they would be all grazed upon by amoeba or if they would be able to survive in the presence of their predator. At a low bacteria-to-amoeba ratio, we show that each bacterium is phagocytized and follows a singular intracellular path within this host cell, which appears to delay or to prevent bacterial digestion. In particular, one of the bacteria was found in the amoeba nucleolar compartment whereas another strain was expelled from the amoeba in vesicles. We then looked at the fate of the bacteria grown in a higher bacteria-to-amoeba ratio, as a preformed mono- or multi-species biofilm in the presence of A. castellanii. We show that all biofilms were subjected to detachment from the surface in the presence of the amoeba or its supernatant. Overall, these results show that bacteria, when facing the same predator, exhibit a variety of escape mechanisms at the cellular and population level, when we could have expected a simple bacterial grazing. Therefore, this study unravels new insights into the survival of environmental bacteria when facing predators that they could encounter in the same microbial communities.
The Amino Acid Changes T55A, A273P and R277C in the Beta-Lactamase CTX-M-14 Render E. coli Resistant to the Antibiotic Nitrofurantoin, a First-Line Treatment of Urinary Tract Infections
Authors: Edowik Yasir , Caspari Thomas , Williams Hugh Merfyn
Published: December 2020

The antibiotic nitrofurantoin is a furan flanked by a nitro group and a hydantoin ring. It is used to treat lower urinary tract infections (UTIs) that have a lifetime incidence of 50−60% in adult women. UTIs are typically caused by uropathogenic Escherichia coli (UPEC), which are increasingly expressing extended-spectrum beta-lactamases (ESBL), rendering them multi-drug resistant. Nitrofurantoin is a first-line treatment for gram-negative ESBL-positive UTI patients, given that resistance to it is still rare (0% to 4.4%). Multiplex PCR of β-lactamase genes of the blaCTX-M groups 1, 2, 9 and 8/25 from ESBL-positive UTI patients treated at three referral hospitals in North Wales (UK) revealed the presence of a novel CTX-M-14-like gene harbouring the missense mutations T55A, A273P and R277C. While R277 is close to the active site, T55 and A273 are both located in external loops. Recombinant expression of CTX-M-14 and the mutated CTX-M-14 in the periplasm of E. coli revealed a significant increase in the Minimum Inhibitory Concentration (MIC) for nitrofurantoin from ≥6 μg/mL (CTX-M-14) to ≥512 μg/mL (mutated CTX-M-14). Consistent with this finding, the mutated CTX-M protein hydrolysed nitrofurantoin in a cell-free assay. Detection of a novel nitrofurantoin resistance gene indicates an emerging clinical problem in the treatment of gram-negative ESBL-positive UTI patients.
Post-Vaccination Streptococcus pneumoniae Carriage and Virulence Gene Distribution among Children Less Than Five Years of Age, Cape Coast, Ghana
Authors: Mills Richael O. , Abdullah Mohammed R. , Akwetey Samuel A. , Sappor Dorcas C. , Cole Isaac , Baffuor-Asare Michael , Bolivar Johan A. , Gámez Gustavo , van der Linden Mark P. G. , Hammerschmidt Sven
Published: December 2020

In 2012, Ghana introduced PCV13 into its childhood immunization program. To monitor the pneumococcus after PCV13 vaccination, we analyzed serotypes, antibiotic resistance, and virulence genes of pneumococcal carriage isolates among children under five years of age. We obtained nasopharyngeal swabs from 513 children from kindergartens and immunization centers in Cape Coast, Ghana. Pneumococcal serotypes were determined by multiplex-PCR and Quellung reaction. Antibiotic resistance and virulence genes prevalence were determined by disc diffusion and PCR respectively. Overall, carriage prevalence was 29.4% and PCV13 coverage was 38.4%. Over 60% of the isolates were non-PCV13 serotypes and serotype 23B was the most prevalent. One isolate showed full resistance to penicillin, while 35% showed intermediate resistance. Resistance to erythromycin and clindamycin remained low, while susceptibility to ceftriaxone, levofloxacin and vancomycin remained high. Penicillin resistance was associated with PCV13 serotypes. Forty-three (28.5%) strains were multidrug-resistant. Virulence genes pavB, pcpA, psrP, pilus-1, and pilus-2 were detected in 100%, 87%, 62.9%, 11.9%, and 6.6% of the strains, respectively. The pilus islets were associated with PCV13 and multidrug-resistant serotypes. PCV13 vaccination had impacted on pneumococcal carriage with a significant increase in non-PCV13 serotypes and lower penicillin resistance. Including PcpA and PsrP in pneumococcal protein-based vaccines could be beneficial to Ghanaian children.
Ore Mineralogy, Trace Element Geochemistry and Geochronological Constraints at the Mollehuaca and San Juan de Chorunga Au-Ag Vein Deposits in the Nazca-Ocoña Metallogenic Belt, Arequipa, Peru
Authors: Crespo Jorge , Holley Elizabeth , Pfaff Katharina , Guillen Madeleine , Huamani Roberto
Published: December 2020

The Mollehuaca and San Juan de Chorunga deposits are hosted in the poorly explored gold and copper trends of the Nazca-Ocoña metallogenic belt in Arequipa, Perú, which extends from Trujillo (9 °S) to Nazca-Ocoña (14 °S). The aim of this study is to characterize the age, occurrence, and distribution of quartz vein-hosted Au-Ag mineralization and associated trace elements (e.g., Hg, Pb, Cu, Zn, and Bi) in these deposits. Here, we present geological mapping, geochemical whole rock inductively coupled plasma (ICP)-MS data of the veins, petrographic observations, backscattered electron images, quantitative SEM-based automated mineralogy, and electron microprobe analyses (EMPA). Despite the fact that there are numerous small-scale gold mines in the Nazca-Ocoña metallogenic belt, there have been few studies that document the origin and geological evolution of these deposits or the implications for decision-making in exploration, metallurgical processing, and environmental management. In this research, we document the host rock age of the mineralized veins (129.2 ± 1.0 Ma; U-Pb in zircon), the mineralization age (95.86 ± 0.05 Ma; 40Ar/39Ar in secondary biotite), the occurrence and distribution of Au-Ag in the veins, the mineral zonation present in the vein system, and the zircon geochemistry, in order to provide tools for natural resource management in the metallogenic belt.
Geochemical Data and Fluid Inclusion Study of the Middle Miocene Halite from Deep Borehole Huwniki-1, Situated in the Inner Zone of the Carpathian Foredeep in Poland
Authors: Bukowski Krzysztof , Galamay Anatoliy , Krzywiec Piotr , Maksym Andrzej
Published: December 2020

The geochemical data and the study of fluid inclusions in primary halite are invaluable sources of saline basin information. Most of the previous analyses of salt from the Carpathian area have been obtained by studying the halite samples collected from depths not exceeding 1000 m (i.e., from salt mine outcrops or boreholes). In this article, for the first time, we present the results of samples obtained from a deep well where salt occurs below the frontal orogenic wedge at a depth of ~5000 m. The salt core’s petrological studies showed, quite unexpectedly, the presence of the chevron relics, typical for primary halite. Their geochemical data and fluid inclusion study can be used to reconstruct the environment of the salt sedimentation. The bromine, strontium, and rubidium content values indicated that primary brines were of marine origin, and salts may have undergone partial dissolution and redeposition under lower salinity water inflows. The main ions’ (K, Mg, SO4) ratios in the fluid inclusions were typical for those of the Badenian brines collected from the Carpathian Foredeep’s eastern part. Compared with modern seawater’s chemical composition, this brine contained a slightly lower content of sulfate ions. This was associated with evolutionary changes occurring in the contents of sulfate ions during the Cenozoic.
Self-Healing Biogeopolymers Using Biochar-Immobilized Spores of Pure- and Co-Cultures of Bacteria
Authors: Doctolero Jadin Zam S. , Beltran Arnel B. , Uba Marigold O. , Tigue April Anne S. , Promentilla Michael Angelo B.
Published: December 2020

A sustainable solution for crack maintenance in geopolymers is necessary if they are to be the future of modern green construction. This study aims to develop self-healing biogeopolymers that could potentially rival bioconcrete. First, a suitable healing agent was selected from Bacillus subtilis, Bacillus sphaericus, and Bacillus megaterium by directly adding their spores in the geopolymers and subsequently exposing them to a precipitation medium for 14 days. Scanning electron microscope with energy-dispersive X-ray (SEM-EDX) analysis revealed the formation of mineral phases for B. subtilis and B. sphaericus. Next, the effect of biochar-immobilization and co-culturing (B. sphaericus and B. thuringiensis) on the healing efficiencies of the geopolymers were tested and optimized by measuring their ultrasonic pulse velocities weekly over a 28-day healing period. The results show that using co-cultured bacteria significantly improved the observed efficiencies, while biochar-immobilization had a weak effect, but yielded an optimum response between 0.3–0.4 g/mL. The maximum crack width sealed was 0.65 mm. Through SEM-EDX and FTIR analyses, the precipitates in the cracks were identified to be mainly CaCO3. With that, there is potential in developing self-healing biogeopolymers using biochar-immobilized spores of bacterial cultures.
Post-Magmatic Fluids Dominate the Mineralization of Dolomite Carbonatitic Dykes Next to the Giant Bayan Obo REE Deposit, Northern China
Authors: Hu Le , Li Yike , Chuan Maoshan , Li Ruiping , Ke Changhui , Wu Zhongjian
Published: December 2020

The Bayan Obo rare earth element (REE) deposit in Inner Mongolia, northern China, is the largest REE deposit in the world, whose mineralization process remains controversial. There are dozens of carbonatite dykes that are tightly related to the deposit. Here we report the petrological and mineralogical characteristics of a typical dolomite carbonatite dyke near the deposit. The dolomite within the dyke experienced intense post-emplacement fluids metasomatism as evidenced by the widespread hydrothermal REE-bearing minerals occurring along the carbonate mineral grains. REE contents of bulk rocks and constituent dolomite minerals (>90 vol.%) are 1407–4184 ppm and 63–152 ppm, respectively, indicating that dolomite is not the dominant mineral controlling the REE budgets of the dyke. There are three types of apatite in the dyke: Type 1 apatite is the primary apatite and contains REE2O3 at 2.35–4.20 wt.% and SrO at 1.75–2.19 wt.%; Type 2 and Type 3 apatites are the products of replacement of primary apatite. The REE2O3 (6.10–8.21 wt.%) and SrO (2.83–3.63 wt.%) contents of Type 2 apatite are significantly elevated for overprinting of REE and Sr-rich fluids derived from the carbonatite. Conversely, Type 3 apatite has decreased REE2O3 (1.17–2.35 wt.%) and SrO (1.51–1.99 wt.%) contents, resulting from infiltration of fluids with low REE and Na concentrations. Our results on the dyke suggest that post-magmatic fluids expelled from the carbonatitic melts dominated the REE mineralization of the Bayan Obo deposit, and a significant fluid disturbance occurred but probably provided no extra REEs to the deposit.
Design, Synthesis and Fungicidal Activity of New 1,2,4-Triazole Derivatives Containing Oxime Ether and Phenoxyl Pyridinyl Moiety
Authors: Bai Hui , Liu Xuelian , Chenzhang Pengfei , Xiao Yumei , Fu Bin , Qin Zhaohai
Published: December 2020

A series of novel 1,2,4-triazole derivatives containing oxime ether and phenoxy pyridine moiety were designed and synthesized. The new compounds were identified by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HRMS). Compound (Z)-1-(6-(4-nitrophenoxy)pyridin-3-yl)-2-(1H-1,2,4-triazol-1-yl)ethan-1-one O-methyl oxime (5a18) was further confirmed by X-ray single crystal diffraction. Their antifungal activities were evaluated against eight phytopathogens. The in vitro bioassays indicated that most of the title compounds displayed moderate to high fungicidal activities. Compound (Z)-1-(6-(4-bromo-2-chlorophenoxy)pyridin-3-yl)-2-(1H-1,2,4-triazol-1-yl)ethan-1-one O-methyl oxime (5a4) exhibited a broad-spectrum antifungal activities with the EC50 values of 1.59, 0.46, 0.27 and 11.39 mg/L against S. sclerotiorum, P. infestans, R. solani and B. cinerea, respectively. Compound (Z)-1-(6-(2-chlorophenoxy)pyridin-3-yl)-2-(1H-1,2,4-triazol-1-yl)ethan-1-one O-benzyl oxime (5b2) provided the lowest EC50 value of 0.12 mg/L against S. sclerotiorum, which were comparable to the commercialized difenoconazole. Moreover, homologous modeling and molecular docking disclosed possible binding modes of compounds 5a4 and 5b2 with CYP51. This work provided useful guidance for the discovery of new 1,2,4-triazole fungicides.
Simulating Absorption Spectra of Flavonoids in Aqueous Solution: A Polarizable QM/MM Study
Authors: Skoko Sulejman , Ambrosetti Matteo , Giovannini Tommaso , Cappelli Chiara
Published: December 2020

We present a detailed computational study of the UV/Vis spectra of four relevant flavonoids in aqueous solution, namely luteolin, kaempferol, quercetin, and myricetin. The absorption spectra are simulated by exploiting a fully polarizable quantum mechanical (QM)/molecular mechanics (MM) model, based on the fluctuating charge (FQ) force field. Such a model is coupled with configurational sampling obtained by performing classical molecular dynamics (MD) simulations. The calculated QM/FQ spectra are compared with the experiments. We show that an accurate reproduction of the UV/Vis spectra of the selected flavonoids can be obtained by appropriately taking into account the role of configurational sampling, polarization, and hydrogen bonding interactions.
Panax quinquefolius (North American Ginseng) Polysaccharides as Immunomodulators: Current Research Status and Future Directions
Authors: Ghosh Rajarshi , Bryant Daniel L. , Farone Anthony L.
Published: December 2020

Panax quinquefolius (North American ginseng, NAG) is a popular medicinal plant used widely in traditional medicine. NAG products are currently available in various forms such as roots, extracts, nutraceuticals, dietary supplements, energy drinks, etc. NAG polysaccharides are recognized as one of the major bioactive ingredients. However, most NAG reviews are focused on ginsenosides with little information on polysaccharides. NAG polysaccharides have demonstrated a therapeutic activity in numerous studies, in which many of the bioactivities involve regulation of the immune response. The purpose of this review is to summarize the structural features and the immunomodulatory properties of crude, partially purified, and pure polysaccharides isolated from NAG. Receptors of the innate immune system that potentially bind to NAG polysaccharides and the respective signal transduction pathways initiated by these compounds are discussed. Major challenges, recent innovations, and future directions in NAG polysaccharide research are also summarized.
Cytotoxic Plant Extracts towards Insect Cells: Bioactivity and Nanoencapsulation Studies for Application as Biopesticides
Authors: Lopes Ana I. F. , Monteiro Mariana , Araújo Ana R. L. , Rodrigues Ana Rita O. , Castanheira Elisabete M. S. , Pereira David M. , Olim Pedro , Fortes A. Gil , Gonçalves M. Sameiro T.
Published: December 2020

The potential of plant extracts as bioinsecticides has been described as a promising field of agricultural development. In this work, the extracts of Punica granatum (pomegranate), Phytolacca americana (American pokeweed), Glandora prostrata (shrubby gromwell), Ulex europaeus (gorce), Tagetes patula (French marigold), Camellia japonica red (camellia), Ruta graveolens (rue or herb-of-grace) were obtained, purified, and their activity against Spodoptera frugiperda (Sf9) insect cells was investigated. From the pool of over twenty extracts obtained, comprising different polarities and vegetable materials, less polar samples were shown to be more toxic towards the insect cell line Sf9. Among these, a dichloromethane extract of R. graveolens was capable of causing a loss of viability of over 50%, exceeding the effect of the commercial insecticide chlorpyrifos. This extract elicited chromatin condensation and the fragmentation in treated cells. Nanoencapsulation assays of the cytotoxic plant extracts in soybean liposomes and chitosan nanostructures were carried out. The nanosystems exhibited sizes lower or around 200 nm, low polydispersity, and generally high encapsulation efficiencies. Release assays showed that chitosan nanoemulsions provide a fast and total extract release, while liposome-based systems are suitable for a more delayed release. These results represent a proof-of-concept for the future development of bioinsecticide nanoformulations based on the cytotoxic plant extracts.
Intestinal Population in Host with Metabolic Syndrome during Administration of Chitosan and Its Derivatives
Authors: Yan Chen , Zhang Cuili , Cao Xuejiao , Feng Bin , Li Xinli
Published: December 2020

Chitosan and its derivatives can alleviate metabolic syndrome by different regulation mechanisms, phosphorylation of AMPK (AMP-activated kinase) and Akt (also known as protein kinase B), suppression of PPAR-γ (peroxisome proliferator-activated receptor-γ) and SREBP-1c (sterol regulatory element–binding proteins), and translocation of GLUT4 (glucose transporter-4), and also the downregulation of fatty-acid-transport proteins, fatty-acid-binding proteins, fatty acid synthetase (FAS), acetyl-CoA carboxylase (acetyl coenzyme A carboxylase), and HMG-CoA reductase (hydroxy methylglutaryl coenzyme A reductase). The improved microbial profiles in the gastrointestinal tract were positively correlated with the improved glucose and lipid profiles in hosts with metabolic syndrome. Hence, this review will summarize the current literature illustrating positive correlations between the alleviated conditions in metabolic syndrome hosts and the normalized gut microbiota in hosts with metabolic syndrome after treatment with chitosan and its derivatives, implying that the possibility of chitosan and its derivatives to serve as therapeutic application will be consolidated. Chitosan has been shown to modulate cardiometabolic symptoms (e.g., lipid and glycemic levels, blood pressure) as well as gut microbiota. However, the literature that summarizes the relationship between such metabolic modulation of chitosan and prebiotic-like effects is limited. This review will discuss the connection among their structures, biological properties, and prebiotic effects for the treatment of metabolic syndrome. Our hope is that future researchers will consider the prebiotic effects as significant contributors to the mitigation of metabolic syndrome.
DFT Study on the Mechanism of Iron-Catalyzed Diazocarbonylation
Authors: Kégl Tímea R. , Kollár László , Kégl Tamás
Published: December 2020

The mechanism of the carbonylation of diazomethane in the presence of iron–carbonyl–phosphine catalysts has been investigated by means of DFT calculations at the M06/def-TZVP//B97D3/def2-TZVP level of theory, in combination with the SMD solvation method. The reaction rate is determined by the formation of the coordinatively unsaturated doublet-state Fe(CO)3(P) precursor followed by the diazoalkane coordination and the N2 extrusion. The free energy of activation is predicted to be 18.5 and 28.2 kcal/mol for the PF3 and PPh3 containing systems, respectively. Thus, in the presence of less basic P-donor ligands with stronger π-acceptor properties, a significant increase in the reaction rate can be expected. According to energy decomposition analysis combined with natural orbitals of chemical valence (EDA–NOCV) calculations, diazomethane in the Fe(CO)3(phosphine)(η1-CH2N2) adduct reveals a π-donor–π-acceptor type of coordination.
Exploring Free Energy Profiles of Enantioselective Organocatalytic Aldol Reactions under Full Solvent Influence
Authors: Weiß Moritz , Brehm Martin
Published: December 2020

We present a computational study on the enantioselectivity of organocatalytic proline-catalyzed aldol reactions between aldehydes in dimethylformamide (DMF). To explore the free energy surface of the reaction, we apply two-dimensional metadynamics on top of ab initio molecular dynamics (AIMD) simulations with explicit solvent description on the DFT level of theory. We avoid unwanted side reactions by utilizing our newly developed hybrid AIMD (HyAIMD) simulation scheme, which adds a simple force field to the AIMD simulation to prevent unwanted bond breaking and formation. Our condensed phase simulation results are able to nicely reproduce the experimental findings, including the main stereoisomer that is formed, and give a correct qualitative prediction of the change in syn:anti product ratio with different substituents. Furthermore, we give a microscopic explanation for the selectivity. We show that both the explicit description of the solvent and the inclusion of entropic effects are vital to a good outcome—metadynamics simulations in vacuum and static nudged elastic band (NEB) calculations yield significantly worse predictions when compared to the experiment. The approach described here can be applied to a plethora of other enantioselective or organocatalytic reactions, enabling us to tune the catalyst or determine the solvent with the highest stereoselectivity.
Grindstone Chemistry: Design, One-Pot Synthesis, and Promising Anticancer Activity of Spiro[acridine-9,2′-indoline]-1,3,8-trione Derivatives against the MCF-7 Cancer Cell Line
Authors: Gobinath Perumal , Packialakshmi Ponnusamy , Daoud Ali , Alarifi Saud , Idhayadhulla Akbar , Radhakrishnan Surendrakumar
Published: December 2020

In this study, the synthesis of one-pot 10-phenyl-3,4,6,7-tetrahydro-1H-spiro [acridine-9,2′-indoline]-1,3,8-trione derivatives was achieved via a four-component cyclocondensation reaction, which was carried out in solvent-free conditions, and using p-toluenesulfonic acid (p-TSA) as a catalyst. The product was confirmed by FT-IR, 1H-NMR, 13C-NMR, mass spectra, and elemental analysis. Furthermore, the anticancer activity was screened for all compounds. Among these compounds, compound 1c was more effective (GI50 0.01 µm) against MCF-7 cancer cell lines than standard and other compounds. Therefore, the objective of this study was achieved with a few promising molecules having been demonstrated to be potential anticancer agents.