bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical and Epidemiological Profile of Patients with Invasive Aspergillosis from a Fourth Level Hospital in Bogota, Colombia: A Retrospective Study
Authors: Goyeneche-García Ana , Rodríguez-Oyuela Juan , Sánchez Guillermo , Firacative Carolina
Published: December 2021

Invasive aspergillosis (IA) is a severe mycosis caused by Aspergillus species. The infection mainly affects immunocompromised patients with a significant clinical burden. This study aimed to determine the clinical and epidemiological characteristics of patients diagnosed with IA in a fourth level hospital in Colombia, as these data are scarce in the country. A retrospective, observational study, from a single center was conducted with 34 male and 32 female patients, between 1 month- and 90-year-old, diagnosed with proven (18.2%), probable (74.2%) and possible (7.6%) IA, during a 21-year period. The most frequent underlying conditions for IA were chemotherapy (39.4%) and corticosteroid use (34.8%). The lung was the most common affected organ (92.4%). Computed tomography (CT) imaging findings were mainly nodules (57.6%) and consolidation (31.8%). A low positive correlation was found between serum galactomannan and hospitalization length. Aspergillus fumigatus prevailed (73.3%) in sputum and bronchoalveolar lavage cultures. Most patients were hospitalized in general wards (63.6%) and treated with voriconazole (80.3%). Mortality rate was 15.2%. Common risk factors for IA were identified in the Colombian cohort, including medications and underlying diseases. However, their frequency differs from other countries, reinforcing the idea that local surveillance is essential and at-risk patients should be carefully monitored.
Phylogenetic Reassessment, Taxonomy, and Biogeography of Codinaea and Similar Fungi
Authors: Réblová Martina , Kolařík Miroslav , Nekvindová Jana , Réblová Kamila , Sklenář František , Miller Andrew N. , Hernández-Restrepo Margarita
Published: December 2021

The genus Codinaea is a phialidic, dematiaceous hyphomycete known for its intriguing morphology and turbulent taxonomic history. This polyphasic study represents a new, comprehensive view on the taxonomy, systematics, and biogeography of Codinaea and its relatives. Phylogenetic analyses of three nuclear loci confirmed that Codinaea is polyphyletic. The generic concept was emended; it includes four morphotypes that contribute to its morphological complexity. Ancestral inference showed that the evolution of some traits is correlated and that these traits previously used to delimit taxa at the generic level occur in species that were shown to be congeneric. Five lineages of Codinaea-like fungi were recognized and introduced as new genera: Codinaeella, Nimesporella, Stilbochaeta, Tainosphaeriella, and Xyladelphia. Dual DNA barcoding facilitated identification at the species level. Codinaea and its segregates thrive on decaying plants, rarely occurring as endophytes or plant pathogens. Environmental ITS sequences indicate that they are common in bulk soil. The geographic distribution found using GlobalFungi database was consistent with known data. Most species are distributed in either the Holarctic realm or tropical geographic regions. The ancestral climatic zone was temperate, followed by transitions to the tropics; these fungi evolved primarily in Eurasia and Americas, with subsequent transitions to Africa and Australasia.
Enhanced Virulence of Candida albicans by Staphylococcus aureus: Evidence in Clinical Bloodstream Infections and Infected Zebrafish Embryos
Authors: Wu Yen-Mu , Huang Po-Yen , Cheng Yi-Chuan , Lee Chih-Hua , Hsu Meng-Chieh , Lu Jang-Jih , Wang Shao-Hung
Published: December 2021

Coinfection with Candida and Staphylococcus results in higher mortality in animal studies. However, the pathogenesis and interplay between C. albicans and S. aureus in bloodstream infections (BSIs) is unclear. This study determines the clinical features and outcomes of mixed C. albicans/S. aureus (CA/SA) BSIs and biofilm formation on pathogenesis during coinfection. Demographics and outcomes for mixed BSIs and monomicrobial candidemia were compared. Compared to 115 monomicrobial C. albicans BSIs, 22 patients with mixed CA/SA BSIs exhibited a significantly higher mortality rate and shorter survival time. In vitro and in vivo biofilm analysis showed that C. albicans accounted for the main biofilm architecture, and S. aureus increased its amount. Antibiotic tolerance in S. aureus, which adhered to Candida hyphae observed by scanning electron microscope, was demonstrated by the presence of wild-type C. albicans co-biofilm. Upregulation in exotoxin genes of S. aureus was evidenced by quantitative RT-PCR when a co-biofilm was formed with C. albicans. Mixed CA/SA BSIs result in a higher mortality rate in patients and in vivo surrogate models experiments. This study demonstrates that the virulence enhancement of C. albicans and S. aureus during co-biofilm formation contributes to the high mortality rate.
Precision Medicine in Aortic Anastomosis: A Numerical and Experimental Study of a Novel Double-Sided Needle
Authors: Manolesou Danae G. , Korompili Georgia , Davazoglou Dimitris , Lazaris Andreas M. , Schizas Dimitrios , Sanoudou Despina , Liakakos Theodore , Tsioufis Constantinos , Papaioannou Theodore G.
Published: December 2021

Background: Hand-sewn anastomosis is a crucial part of aortic reconstruction surgery and significantly affects its outcome. The present study presents a novel, bidirectional surgical needle aimed to improve aortic anastomosis in terms of speed and ease of use. Our objective was to assess the efficacy of the new design in comparison with the conventional needle. Methods: A series of simulations were conducted with COMSOL software in order to perform a fatigue comparative analysis between the new and the conventional needle design. Ease of penetration into a piece of polydimethylsiloxane was evaluated. Lastly, the prototype was tested under in-vitro conditions in comparison with the conventional needle. Results: Based on fatigue analysis, the new needle design improves durability, provided the two tips are equally used. The polytetrafluoroethylene coating improves penetration into the tissue by 7% to 17%, while electropolishing improves penetration up to 19%. When using the novel needle design, the average anastomotic task completion time was significantly reduced by 22% and the overall distance of hand movements was significantly reduced by 20%. Conclusions: The proposed design exhibited a shorter anastomotic time and seems promising in relation to ease of use and simplicity of the anastomotic technique it introduces.
COVID-19 Vaccinations and the Volatility of Energy Companies in International Markets
Authors: Demir Ender , Kizys Renatas , Rouatbi Wael , Zaremba Adam
Published: December 2021

The COVID-19 pandemic has elevated both the risk and volatility of energy companies. Can mass vaccinations restore stability within this sector? To answer this question, we investigate stock market data from fifty-eight countries from January 2020 to April 2021. We document that vaccination programs assist in decreasing the volatility of energy stocks around the world. The drop in volatility is statistically and economically significant and robust to many considerations. The observed phenomenon survives a broad battery of control variables; it is also independent of the employed regression model or the volatility measurement approach. Moreover, the effect is not driven by the dynamics of the pandemic itself or the associated government interventions. Finally, we find the influence of vaccinations on energy stock volatility to be more pronounced in developed markets rather than in emerging ones. Our findings bear clear practical implications: policy makers around the world should consider the essential role of vaccinations in the energy sector.
Inflation Co-Movement Dynamics: A Cross-Country Investigation Using a Continuous Wavelet Approach
Authors: Tiwari Aviral Kumar , Abakah Emmanuel Joel Aikins , Gil-Alana Luis A. , Abakah Moses Kenneth
Published: December 2021

The economic literature provides evidence that inflation rates can co-move across nations because of a host of reasons, ranging from low frequency changes in monetary policy to similar high frequency shocks. Hence, this paper investigates inflation rate co-movements between nine (9) African countries and their bilateral linkages with five (5) developed economies using continuous wavelets at different time scales or frequencies. Specifically, we examine the coherency and the phase relationship in time-frequency space in inflation rates of the selected countries. Several findings are documented. First, inflation rates co-movements in the nine African countries are time varying, multi-scale, and characterized by structural breaks. In addition, we find that inflation co-movements across countries in the Africa sub-region is weak at low frequencies. Furthermore, we find evidence of inflation co-movement between Africa and developed economies, suggesting that central banks and policy-makers in Africa need to monitor international price developments, and analyze their implications for their domestic economies. Second, we find that inflation rates in the selected African countries explain, on average, almost 80% of their own inflation variance over the whole sample period. Spillover analysis reveals that China and Canada account for a greater percentage of inflation variation in Africa.
A Bayesian Semiparametric Realized Stochastic Volatility Model
Authors: Liu Jia
Published: December 2021

This paper proposes a semiparametric realized stochastic volatility model by integrating the parametric stochastic volatility model utilizing realized volatility information and the Bayesian nonparametric framework. The flexible framework offered by Bayesian nonparametric mixtures not only improves the fitting of asymmetric and leptokurtic densities of asset returns and logarithmic realized volatility but also enables flexible adjustments for estimation bias in realized volatility. Applications to equity data show that the proposed model offers superior density forecasts for returns and improved estimates of parameters and latent volatility compared with existing alternatives.
Inflation and Hyperinflation Countries in 2018–2020: Risks of Different Assets and Foreign Trade
Authors: Hilmola Olli-Pekka
Published: December 2021

Since the global financial crisis (2008–2009), central banks and governments in developed countries have relied upon loose monetary and financial policy. In the coronavirus pandemic era, these policies were taken even more to the extreme. In 2021, countries around the world started to experience product availability issues, and inflation in some cases was extremely high. There has been debate about the possibility of persistent high inflation. However, risks to assets and foreign trade in this new situation are unknown as all important hyperinflation cases are from decades to century-old. It is important to know what kind of implications high inflation has on modern economies. Therefore, in this study, 10 countries with the highest inflation were selected to be examined in the period of 2018–2020. In these countries, currencies lost a considerable amount of their value against US dollar in 2018–2020. Stock market indexes in many cases provided very high returns in local currency terms; however, against the US dollar, the index yield changed for the substantially negative. Apartment prices in general declined as well. In foreign trade, imports generally declined, while exports were mixed or even increased. However, it should be noted that all of these observations are influenced by the pandemic era and special circumstances of a particular country.
Photobiomodulation Therapy Applied after 6 Months for the Management of a Severe Inferior Alveolar Nerve Injury
Authors: El Mobadder Marwan , Nammour Samir , Ortega Marlin , Grzech-Leśniak Kinga
Published: December 2021

Despite its significant negative impact on the quality of life, the methods for the management of the inferior alveolar nerve (IAN) injury are still limited. In this case report, the patient did not show any improvement from the day of the iatrogenic accident until 6 months. A significant improvement of the symptoms started to appear only at 6 months when PBMT was applied. A total of 42 sessions of PBMT took place. The application zone included intraoral and extraoral areas. The parameters were: Delivery power of 0.1 W, for 40 s, continuous wave (CW), contact mode, and delivered energy of 4 J. The delivered energy density related to the fiber diameter was 1415 J/cm2. Each treated point was considered to be 1 cm2 of diameter. At the end of the treatment, all of the symptoms disappeared except for an abnormal sensation on touching the mucosa and gingiva of the concerned area. No side effects were noted. This case report shows that PBMT can be a very promising approach for the management of severe cases that are not improving with conventional methods.
Pillars and Gaps of S-Nitrosylation-Dependent Epigenetic Regulation in Physiology and Cancer
Authors: Salvatori Luisa , Spallotta Francesco , Gaetano Carlo , Illi Barbara
Published: December 2021

Nitric oxide (NO) is a diffusible signaling molecule produced by three isoforms of nitric oxide synthase, which release NO during the metabolism of the amino acid arginine. NO participates in pathophysiological responses of many different tissues, inducing concentration-dependent effect. Indeed, while low NO levels generally have protective effects, higher NO concentrations induce cytotoxic/cytostatic actions. In recent years, evidences have been accumulated unveiling S-nitrosylation as a major NO-dependent post-translational mechanism ruling gene expression. S-nitrosylation is a reversible, highly regulated phenomenon in which NO reacts with one or few specific cysteine residues of target proteins generating S-nitrosothiols. By inducing this chemical modification, NO might exert epigenetic regulation through direct effects on both DNA and histones as well as through indirect actions affecting the functions of transcription factors and transcriptional co-regulators. In this light, S-nitrosylation may also impact on cancer cell gene expression programs. Indeed, it affects different cell pathways and functions ranging from the impairment of DNA damage repair to the modulation of the activity of signal transduction molecules, oncogenes, tumor suppressors, and chromatin remodelers. Nitrosylation is therefore a versatile tool by which NO might control gene expression programs in health and disease.
Enhanced Conformational Sampling of Nanobody CDR H3 Loop by Generalized Replica-Exchange with Solute Tempering
Authors: Higashida Ren , Matsunaga Yasuhiro
Published: December 2021

The variable domains of heavy-chain antibodies, known as nanobodies, are potential substitutes for IgG antibodies. They have similar affinities to antigens as antibodies, but are more heat resistant. Their small size allows us to exploit computational approaches for structural modeling or design. Here, we investigate the applicability of an enhanced sampling method, a generalized replica-exchange with solute tempering (gREST) for sampling CDR-H3 loop structures of nanobodies. In the conventional replica-exchange methods, temperatures of only a whole system or scaling parameters of a solute molecule are selected for temperature or parameter exchange. In gREST, we can flexibly select a part of a solute molecule and a part of the potential energy terms as a parameter exchange region. We selected the CDR-H3 loop and investigated which potential energy term should be selected for the efficient sampling of the loop structures. We found that the gREST with dihedral terms can explore a global conformational space, but the relaxation to the global equilibrium is slow. On the other hand, gREST with all the potential energy terms can sample the equilibrium distribution, but the structural exploration is slower than with dihedral terms. The lessons learned from this study can be applied to future studies of loop modeling.
Building the E-Commerce Supply Chain of the Future: What Influences Consumer Acceptance of Alternative Places of Delivery on the Last-Mile
Authors: Asdecker Björn
Published: December 2021

Background: To cope with the expected further growth in e-commerce and to be able to continue delivering at low costs, new concepts for the last-mile are needed. This paper reviews the literature and qualitatively investigates which factors influence the acceptance of four alternative place-of-delivery innovations in a business-to-consumer (B2C) context: (1) parcel lockers, (2) reception boxes, (3) trunk delivery, and (4) home access systems; Methods: The available literature was reviewed. Furthermore, 37 interviews were conducted and analyzed using the deductive category development method. In the following, abductive reasoning can derive detailed research models that may form the basis for future confirmative studies; Results: The research gains more detailed insights into how consumers perceive innovative last-mile place-of-delivery concepts. The study provides a clearer picture of what factors influence the intention to use such alternative services; Conclusions: The results can be used by logistics service providers and e-tailers through targeted communication efforts and lay the groundwork for further confirmatory research.
Serum Fibroblast Growth Factor 21 Levels in Children and Adolescents with Hashimoto’s Thyroiditis before and after l-Thyroxin Medication: A Prospective Study
Authors: Drongitis Pavlos , Kotanidou Eleni P , Serbis Anastasios , Tsinopoulou Vasiliki Rengina , Gerou Spyridon , Galli-Tsinopoulou Assimina
Published: December 2021

Backgrounds and Objectives: Fibroblast growth factor 21 (FGF-21) is a complex hormone, sharing common sites of action with thyroid hormones. We investigated the association among FGF-21 levels, resting metabolic rate (RMR), and l-thyroxin (LT4) treatment in children and adolescents with Hashimoto’s thyroiditis. Materials and Methods: A total of 60 youngsters with chronic autoimmune thyroiditis (AIT) (30 with subclinical hypothyroidism, 30 with euthyroidism) and 30 age and sex-matched healthy participants (5–18 years old) were enrolled in the study. Anthropometric, biochemical parameters, and RMR levels were assessed in all participants; serum FGF-21 levels were measured in the control group and the group with subclinical hypothyroidism before and six months after medication with LT4. Results: FGF-21 levels were lower in the treatment group compared with the healthy ones, but this difference was not statistically significant (p > 0.05); despite the increase in FGF-21 levels after six months of LT4 treatment, this difference was not statistically significant (p > 0.05). Free thyroxin (FT4) levels correlated well with FGF-21 levels (r = 0.399, p < 0.01), but further analysis revealed no interaction between these two variables. Both patient groups presented elevated triglyceride (TG) levels compared to controls (p < 0.05). LT4 treatment had no impact on RMR and lipid or liver or glycaemic parameters. An increase in fat mass and fat-free mass were reported, independently of FGF-21 levels. Conclusions: In youngsters with subclinical hypothyroidism due to Hashimoto’s thyroiditis, the serum FGF-21 levels are not significantly lower than in healthy individuals and increase after treatment with LT4 without a statistical significance. Further studies with a large number of young patients and severe hypothyroidism are recommended to confirm our results.
Effects of Antiviral Therapy and Glucocorticoid Therapy on Fever Duration in Pediatric Patients with Influenza
Authors: Han Ji Yoon , Yang Eun Ae , Rhim Jung-Woo , Han Seung Beom
Published: December 2021

Background and Objectives: Considering developing resistance against neuraminidase inhibitors (NAIs) and their adverse reactions, restricted use of NAIs and use of alternative drugs should be considered for treating influenza. Although glucocorticoids (GCs) have been used for severe influenza, their effects on non-severe influenza have rarely been evaluated. This study aimed to evaluate the clinical responses to NAI therapy and GC therapy in pediatric patients with non-severe influenza. Materials and Methods: A total of 601 pediatric patients (<19 years of age) diagnosed with non-severe influenza were retrospectively recruited to evaluate the effects of NAI therapy and GC therapy. Post-admission fever duration and hospitalization duration were compared among four patient groups divided by the administered treatment: No therapy (n = 52), NAI therapy (n = 154), GC therapy (n = 123), and Both therapies (n = 272). Results: In a multivariate analysis with adjustment for confounding variables, the post-admission fever duration was not significantly different among the four patient groups. The post-admission fever duration tended to shorten with increasing age, longer pre-admission fever duration, and incidence of influenza A virus infection and lower respiratory tract infection. The type of administered treatment showed no significant effects on the post-admission fever duration in any subgroups according to patient age, pre-admission fever duration, influenza virus subtype, and clinical diagnosis. Conclusions: Symptomatic treatment rather than antiviral or GC therapy seems to be sufficient for patients with non-severe influenza, although the effects of NAI therapy and GC therapy according to their administered time and dose should be further evaluated.
Preclinical Trial of Traditional Plant Remedies for the Treatment of Complications of Gestational Malaria
Authors: Amadi Peter Uchenna , Agomuo Emmanuel Nnabugwu , Ukaga Chinyere Nneka , Njoku Uche Chinedu , Amadi Joy Adaku , Nwaekpe Chinweuba Godswill
Published: December 2021

Background: Most pregnant women living in high malaria endemic regions of Nigeria use herbal remedies for the management of malaria-in-pregnancy, rather than the commonly prescribed drugs. Remedies common to this area involve a suspension of A. indica (AI) leaves and in some cases, a suspension containing a mixture of AI and D.edulis (PS). Aim: This study examined the therapeutic efficacies of AI, PS, or a combination of AI and PS in a pregnant rat model for exoerythrocytic stages of Plasmodium falciparum parasite. Method: A predetermined sample size of 30 dams was used (for a power level and confidence interval of 95%), and divided equally into six groups made up of non-malarous dams, untreated malarous dams, and malarous dams either treated exclusively with 1 mL of 3000 mg/kg b.w AI, 1000 mg/kg b.w PS, AI + PS (50% v/v), or 25 mg/kg b.w CQ. Result: No maternal mortality was recorded. AI significantly improved maternal weight gain from 32.4 to 82.2 g and placental weight from 0.44 to 0.53 g. In the curative test, AI and AI + PS significantly reduced the average percentage parasitemia (APP) in the pregnant rats from >80% to <20%. No significant difference in the APP was found between the pregnant rats treated with any of CQ or AI during the suppressive test. Results for the prophylactic test of the study groups showed that the APP was significantly reduced from 24.69% to 3.90% when treated with AI and 3.67% when combined with PS. AI + PS reduced diastolic blood pressure from 89.0 to 81.0 mm/Hg and compared with that of the non malarous dams. AI or AI + PS significantly increased the platelet counts (103 µL) from 214.1 to 364.5 and 351.2, respectively. AI and AI + PS improved birth weight from 2.5 to 3.9 g and crown rump length from 2.6 to 4.1 cm. For biomarkers of preeclampsia, combining AI and PS led to the reversal of the altered levels of creatine kinase, lactate dehydrogenase, cardiac troponin, soluble Fms-Like Tyrosine Kinase-1, and placental growth factor. Conclusions: This study validates the use of A. indica for the treatment of gestational malaria due to its antiplasmodial and related therapeutic effects and in combination with pear seeds for the management of malaria-in-pregnancy-induced preeclampsia.
Antibacterial Ferroelectric Hybrid Membranes Fabricated via Electrospinning for Wound Healing
Authors: Lukiev Ivan V. , Antipina Ludmila S. , Goreninskii Semen I. , Tverdokhlebova Tamara S. , Vasilchenko Dmitry V. , Nemoykina Anna L. , Goncharova Daria A. , Svetlichnyi Valery A. , Dambaev Georgiy T. , Bouznik Vyacheslav M. , Bolbasov Evgeny N.
Published: December 2021

In the present study, wound healing ferroelectric membranes doped with zinc oxide nanoparticles were fabricated from vinylidene fluoride-tetrafluoroethylene copolymer and polyvinylpyrrolidone using the electrospinning technique. Five different ratios of vinylidene fluoride-tetrafluoroethylene to polyvinylpyrrolidone were used to control the properties of the membranes at a constant zinc oxide nanoparticle content. It was found that an increase of polyvinylpyrrolidone content leads to a decrease of the spinning solution conductivity and viscosity, causing a decrease of the average fiber diameter and reducing their strength and elongation. By means of X-ray diffraction and infrared spectroscopy, it was revealed that increased polyvinylpyrrolidone content leads to difficulty in crystallization of the vinylidene fluoride-tetrafluoroethylene copolymer in the ferroelectric β-phase in membranes. Changing the ratio of vinylidene fluoride-tetrafluoroethylene copolymer and polyvinylpyrrolidone with a constant content of zinc oxide nanoparticles is an effective approach to control the antibacterial properties of membranes towards Staphylococcus aureus. After carrying out in vivo experiments, we found that ferroelectric hybrid membranes, containing from five to ten mass percent of PVP, have the greatest wound-healing effect for the healing of purulent wounds.
Separation Iron(III)-Manganese(II) via Supported Liquid Membrane Technology in the Treatment of Spent Alkaline Batteries
Authors: Alguacil Francisco J. , Lopez Félix A.
Published: December 2021

In this paper, the transport of iron(III) from iron(III)-manganese(II)-hydrochloric acid mixed solutions, coming from the treatment of spent alkaline batteries through a flat-sheet supported liquid membrane, is investigated (the carrier phase being of Cyanex 923 (commercially available phosphine oxide extractant) dissolved in Solvesso 100 (commercially available diluent)). Iron(III) transport is studied as a function of hydrodynamic conditions, the concentration of manganese and HCl in the feed phase, and the carrier concentration in the membrane phase. A transport model is derived that describes the transport mechanism, consisting of diffusion through a feed aqueous diffusion layer, a fast interfacial chemical reaction, and diffusion of the iron(III) species-Cyanex 923 complex across the membrane phase. The membrane diffusional resistance (Δm) and feed diffusional resistance (Δf) are calculated from the model, and their values are 145 s/cm and 361 s/cm, respectively. It is apparent that the transport of iron(III) is mainly controlled by diffusion through the aqueous feed boundary layer, this being the thickness of this layer calculated as 2.9 × 10−3 cm. Since manganese(II) is not transported through the membrane phase, the present system allows the purification of these manganese-bearing solutions.
Recent Progress on Nanomaterial-Based Membranes for Water Treatment
Authors: Khraisheh Majeda , Elhenawy Salma , AlMomani Fares , Al-Ghouti Mohammad , Hassan Mohammad K. , Hameed Bassim H.
Published: December 2021

Nanomaterials have emerged as the new future generation materials for high-performance water treatment membranes with potential for solving the worldwide water pollution issue. The incorporation of nanomaterials in membranes increases water permeability, mechanical strength, separation efficiency, and reduces fouling of the membrane. Thus, the nanomaterials pave a new pathway for ultra-fast and extremely selective water purification membranes. Membrane enhancements after the inclusion of many nanomaterials, including nanoparticles (NPs), two-dimensional (2-D) layer materials, nanofibers, nanosheets, and other nanocomposite structural materials, are discussed in this review. Furthermore, the applications of these membranes with nanomaterials in water treatment applications, that are vast in number, are highlighted. The goal is to demonstrate the significance of nanomaterials in the membrane industry for water treatment applications. It was found that nanomaterials and nanotechnology offer great potential for the advancement of sustainable water and wastewater treatment.
Identification of a Spatio-Temporal Temperature Model for Laser Metal Deposition
Authors: Kahl Matthias , Schramm Sebastian , Neumann Max , Kroll Andreas
Published: December 2021

Laser-based additive manufacturing enables the production of complex geometries via layer-wise cladding. Laser metal deposition (LMD) uses a scanning laser source to fuse in situ deposited metal powder layer by layer. However, due to the excessive number of influential factors in the physical transformation of the metal powder and the highly dynamic temperature fields caused by the melt pool dynamics and phase transitions, the quality and repeatability of parts built by this process is still challenging. In order to analyze and/or predict the spatially varying and time dependent thermal behavior in LMD, extensive work has been done to develop predictive models usually by using finite element method (FEM). From a control-oriented perspective, simulations based on these models are computationally too expensive and are thus not suitable for real-time control applications. In this contribution, a spatio-temporal input–output model based on the heat equation is proposed. In contrast to other works, the parameters of the model are directly estimated from measurements of the LMD process acquired with an infrared (IR) camera during processing specimens using AISI 316 L stainless steel. In order to deal with noisy data, system identification techniques are used taking different disturbing noise into account. By doing so, spatio-temporal models are developed, enabling the prediction of the thermal behavior by means of the radiance measured by the IR camera in the range of the considered processing parameters. Furthermore, in the considered modeling framework, the computational effort for thermal prediction is reduced compared to FEM, thus enabling the use in real-time control applications.
The Evolution of Intermetallic Compounds in High-Entropy Alloys: From the Secondary Phase to the Main Phase
Authors: Liu Junqi , Wang Xiaopeng , Singh Ajit , Xu Hui , Kong Fantao , Yang Fei
Published: December 2021

High-performance structural materials are critical to the development of transportation, energy, and aerospace. In recent years, newly developed high-entropy alloys with a single-phase solid-solution structure have attracted wide attention from researchers due to their excellent properties. However, this new material also has inevitable shortcomings, such as brittleness at ambient temperature and thermodynamic instability at high temperature. Efforts have been made to introduce a small number of intermetallic compounds into single-phase solid-solution high-entropy alloys as a secondary phase to their enhance properties. Various studies have suggested that the performance of high-entropy alloys can be improved by introducing more intermetallic compounds. At that point, researchers designed an intermetallic compound-strengthened high-entropy alloy, which introduced a massive intermetallic compound as a coherent strengthening phase to further strengthen the matrix of the high-entropy alloy. Inspired from this, Fantao obtained a new alloy—high-entropy intermetallics—by introducing different alloying elements to multi-principalize the material in a previous study. This new alloy treats the intermetallic compound as the main phase and has advantages of both structural and functional materials. It is expected to become a new generation of high-performance amphibious high-entropy materials across the field of structure and function. In this review, we first demonstrate the inevitability of intermetallic compounds in high-entropy alloys and explain the importance of intermetallic compounds in improving the properties of high-entropy alloys. Secondly, we introduce two new high-entropy alloys mainly from the aspects of composition design, structure, underlying mechanism, and performance. Lastly, the high-entropy materials containing intermetallic compound phases are summarized, which lays a theoretical foundation for the development of new advanced materials.
Comparative Metabolomics Reveals Two Metabolic Modules Affecting Seed Germination in Rice (Oryza sativa)
Authors: Guo Hao , Lyv Yuanyuan , Zheng Weikang , Yang Chenkun , Li Yufei , Wang Xuyang , Chen Ridong , Wang Chao , Luo Jie , Qu Lianghuan
Published: December 2021

The process of seed germination is crucial not only for the completion of the plant life cycle but also for agricultural production and food chemistry; however, the underlying metabolic regulation mechanism involved in this process is still far from being clearly revealed. In this study, one indica variety (Zhenshan 97, with rapid germination) and one japonica variety (Nipponbare, with slow germination) in rice were used for in-depth analysis of the metabolome at different germination stages (0, 3, 6, 9, 12, 24, 36, and 48 h after imbibition, HAI) and exploration of key metabolites/metabolic pathways. In total, 380 annotated metabolites were analyzed by using a high-performance liquid chromatography (HPLC)-based targeted method combined with a nontargeted metabolic profiling method. By using bioinformatics and statistical methods, the dynamic changes in metabolites during germination in the two varieties were compared. Through correlation analysis, coefficient of variation analysis and differential accumulation analysis, 74 candidate metabolites that may be closely related to seed germination were finally screened. Among these candidates, 29 members belong to the ornithine–asparagine–polyamine module and the shikimic acid–tyrosine–tryptamine–phenylalanine–flavonoid module. As the core member of the second module, shikimic acid’s function in the promotion of seed germination was confirmed by exogenous treatment. These results told that nitrogen flow and antioxidation/defense responses are potentially crucial for germinating seeds and seedlings. It deepens our understanding of the metabolic regulation mechanism of seed germination and points out the direction for our future research.
Obesogens in Children—An Uncharted Territory
Authors: Močnik Mirjam , Marčun Varda Nataša
Published: December 2021

Obesogens are exogenous chemicals belonging to the group of endocrine-disrupting chemicals and are believed to interfere in obesity development. In children, several chemicals are under investigation, most commonly bisphenol A, phthalates, perfluorinated alkyl substances, and persistent organic pollutants, including organochlorinated pesticides, tributyltin, polychlorinated biphenyls and dioxins. Several associations have been studied between chemical exposure in utero and postnatally. Current opinion among researchers indicates that the obesogen theory is very likely; however, limited published studies show inconsistent support for the obesogenic effects of most substances in children and are limited by difficulty in providing the exact mechanisms of action, nor is their mutual effect in humans known, let alone in children. Existing data indicate that we have only scratched the surface and have much more to learn about obesogens. Hopefully, in the future, more information will provide an opportunity for policy makers to take action and protect public health.
Plasma Acylcarnitines during Pregnancy and Neonatal Anthropometry: A Longitudinal Study in a Multiracial Cohort
Authors: Song Yiqing , Lyu Chen , Li Ming , Rahman Mohammad L. , Chen Zhen , Zhu Yeyi , Hinkle Stefanie N. , Chen Liwei , Mitro Susanna D. , Li Ling-Jun , Weir Natalie L. , Tsai Michael Y. , Zhang Cuilin
Published: December 2021

As surrogate readouts reflecting mitochondrial dysfunction, elevated levels of plasma acylcarnitines have been associated with cardiometabolic disorders, such as obesity, gestational diabetes, and type 2 diabetes. This study aimed to examine prospective associations of acylcarnitine profiles across gestation with neonatal anthropometry, including birthweight, birthweight z score, body length, sum of skinfolds, and sum of body circumferences. We quantified 28 acylcarnitines using electrospray ionization tandem mass spectrometry in plasma collected at gestational weeks 10–14, 15–26, 23–31, and 33–39 among 321 pregnant women from the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singletons. A latent-class trajectory approach was applied to identify trajectories of acylcarnitines across gestation. We examined the associations of individual acylcarnitines and distinct trajectory groups with neonatal anthropometry using weighted generalized linear models adjusting for maternal age, race/ethnicity, education, parity, gestational age at blood collection, and pre-pregnancy body mass index (BMI). We identified three distinct trajectory groups in C2, C3, and C4 and two trajectory groups in C5, C10, C5–DC, C8:1, C10:1, and C12, respectively. Women with nonlinear decreasing C12 levels across gestation (5.7%) had offspring with significantly lower birthweight (−475 g; 95% CI, −942, −6.79), birthweight z score (−0.39, −0.71, −0.06), and birth length (−1.38 cm, −2.49, −0.27) than those with persistently stable C12 levels (94.3%) (all nominal p value < 0.05). Women with consistently higher levels of C10 (6.1%) had offspring with thicker sum of skinfolds (4.91 mm, 0.85, 8.98) than did women with lower levels (93.9%) during pregnancy, whereas women with lower C10:1 levels (12.6%) had offspring with thicker sum of skinfolds (3.23 mm, 0.19, 6.27) than did women with abruptly increasing levels (87.4%) (p < 0.05). In conclusion, this study suggests that distinctive trajectories of C10, C10:1, and C12 acylcarnitine levels throughout pregnancy were significantly associated with neonatal anthropometry.
Individual Microparticle Manipulation Using Combined Electroosmosis and Dielectrophoresis through a Si3N4 Film with a Single Micropore
Authors: Lyu Chenang , Lou Leo , Powell-Palm Matthew J. , Ukpai Gideon , Li Xing , Rubinsky Boris
Published: December 2021

Porous dielectric membranes that perform insulator-based dielectrophoresis or electroosmotic pumping are commonly used in microchip technologies. However, there are few fundamental studies on the electrokinetic flow patterns of single microparticles around a single micropore in a thin dielectric film. Such a study would provide fundamental insights into the electrokinetic phenomena around a micropore, with practical applications regarding the manipulation of single cells and microparticles by focused electric fields. We have fabricated a device around a silicon nitride film with a single micropore (2–4 µm in diameter) which has the ability to locally focus electric fields on the micropore. Single microscale polystyrene beads were used to study the electrokinetic flow patterns. A mathematical model was developed to support the experimental study and evaluate the electric field distribution, fluid motion, and bead trajectories. Good agreement was found between the mathematic model and the experimental data. We show that the combination of electroosmotic flow and dielectrophoretic force induced by direct current through a single micropore can be used to trap, agglomerate, and repel microparticles around a single micropore without an external pump. The scale of our system is practically relevant for the manipulation of single mammalian cells, and we anticipate that our single-micropore approach will be directly employable in applications ranging from fundamental single cell analyses to high-precision single cell electroporation or cell fusion.
Microfluidic Chip with Two-Stage Isothermal Amplification Method for Highly Sensitive Parallel Detection of SARS-CoV-2 and Measles Virus
Authors: Huang Qin , Shan Xiaohui , Cao Ranran , Jin Xiangyu , Lin Xue , He Qiurong , Zhu Yulei , Fu Rongxin , Du Wenli , Lv Wenqi , Xia Ying , Huang Guoliang
Published: December 2021

A two-stage isothermal amplification method, which consists of a first-stage basic recombinase polymerase amplification (RPA) and a second-stage fluorescence loop-mediated isothermal amplification (LAMP), as well as a microfluidic-chip-based portable system, were developed in this study; these enabled parallel detection of multiplex targets in real time in around one hour, with high sensitivity and specificity, without cross-contamination. The consumption of the sample and the reagent was 2.1 μL and 10.6 μL per reaction for RPA and LAMP, respectively. The lowest detection limit (LOD) was about 10 copies. The clinical amplification of about 40 nasopharyngeal swab samples, containing 17 SARS-CoV-2 (severe acute respiratory syndrome coronavirus) and 23 measles viruses (MV), were parallel tested by using the microfluidic chip. Both clinical specificity and sensitivity were 100% for MV, and the clinical specificity and sensitivity were 94.12% and 95.83% for SARS-CoV-2, respectively. This two-stage isothermal amplification method based on the microfluidic chip format offers a convenient, clinically parallel molecular diagnostic method, which can identify different nucleic acid samples simultaneously and in a timely manner, and with a low cost of the reaction reagent. It is especially suitable for resource-limited areas and point-of-care testing (POCT).
Production Methods for Regular Aggregates and Innovative Developments in Poland
Authors: Gawenda Tomasz
Published: December 2021

The aim of this article is to present possibilities of producing aggregates with an increased content of regular particles in some well-known examples, as well as to present previously unused methods of aggregate production. Traditional aggregate production systems require the use of three or four grinding stages (depending on the particle size of the feed), but fine fractions contain approximately 10% irregular grains on average. The conducted research has shown that in innovative patented technological systems, it is possible to obtain regular aggregates with a share of irregular grains below 3%. The separated irregular aggregates can be crushed again or used for other purposes. The advantages of such inventions include less grinding stages, reduced dust, and lower energy consumption. Regular aggregates also have benefits compared to typical ones. The analyzed aggregate products from various mines showed that regular aggregates have better properties, for example, higher resistance to grinding and abrasion. This article also describes the advantages of using such aggregates for concrete or other applications.
Problems of Estimating the Resources of Accompanying Elements: A Case Study from the Cu-Ag Rudna Deposit (Legnica-Głogów Copper District, Poland)
Authors: Auguścik-Górajek Justyna , Mucha Jacek , Wasilewska-Błaszczyk Monika , Kaczmarek Wojciech
Published: December 2021

As a result of the exploitation of ore deposits, in addition to the main elements, the accompanying elements are also partially recovered. Some of them increase the profitability of exploitation, while others reduce it because they hinder the recovery of the main elements and thus increase the costs of the recovery process. A comprehensive economic calculation to assess the profitability of ore mining depends on an appropriately accurate estimation of the resources of both the main and associated elements. This issue was analyzed with the example of the Cu-Ag Rudna ore deposit (LGCD, Poland). The subject of the assessment was the resources prediction accuracy of the main element (Cu) and four (4) accompanying elements (Co, Ni, Pb, and V) using geostatistical estimation method, in particular the ordinary kriging after the estimation of the relative variograms for describing the spatial variability structures of elements abundance. It was found that the standard kriging errors (deviations) in accompanying elements resources that are scheduled for exploitation within a one-year period in some parts of deposits are drastically greater (2 to 5 times) than the estimation errors of the main element resources. This is due to the sparse sampling pattern for their determinations and/or the high variability (among others nugget effect) of their abundance. In this situation, without additional sampling and a denser sampling pattern, the possibilities of a reliable assessment of the influence of accompanying elements on the economic consequences of exploitation are very limited.
Coal Ash Content Measurement Based on Pseudo-Dual Energy X-ray Transmission
Authors: Zhang Xiufeng , Liang Long , Li Taiyou , Tan Jiakun , Liang Xingguo , Xie Guangyuan
Published: December 2021

The real-time ash content measurement is the fundamental condition for the timely adjustment and intelligent control of operation parameters in coal production and utilization industry. In the present work, a real-time ash content analyzer based on the pseudo-dual energy X-ray transmission was developed. The feasibility of this X-ray ash content analyzer was validated by the linear relationship between ash content and five characteristic parameters of X-ray. The conditions of wave filter, tube voltage, and tube current were optimized. The comparison between the ash contents measured by muffle furnace and the X-ray ash content analyzer was conducted in laboratory and industry. It was found that the absolute error was smaller than 1% for clean coal with ash content of approximately 10%, and the possibility of the absolute error smaller than 0.5% was higher than 85%.
Enhanced Flotation Recovery of Fine Molybdenite Particles Using a Coal Tar-Based Collector
Authors: Chao Yande , Li Shulei , Gao Lihui , Sun Lijuan , Li Lingni , Chai Na , Cao Yijun
Published: December 2021

Low flotation efficiency has always been a problem in the separation of low-grade molybdenum ores because of the finely disseminated nature and crystal anisotropy of molybdenite. In this study, a novel kerosene–coal tar collector (KCTC) was prepared and used to explore the feasibility of improving the recovery of fine molybdenite particles. The results showed that KCTC achieved better attaching performance than that shown by kerosene, and the surface coverage and attaching rate constant were improved significantly, especially for finer particles of −38 + 20 μm. Compared with kerosene, KCTC showed more affinity for molybdenite particles and greater adsorbed amounts of KCTC on molybdenite particles were achieved. Moreover, the composite collector was shown to float single molybdenite particles of different sizes, and it was found that the recovery of molybdenite particles of different sizes, particularly in the case of those at −20 μm, was improved dramatically by KCTC. The flotation results of actual molybdenum ores further confirmed that KCTC was beneficial to flotation recovery and the selectivity of molybdenite. This indicated that KCTC is a potential collector for the effective flotation of low-grade deposits of molybdenum ores, and more studies should be conducted on further use in industrial practice.