bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multidimensional Principal Component Analysis via the C-Product Golub–Kahan–SVD for Classification and Face Recognition
Authors: Hached Mustapha , Jbilou Khalide , Koukouvinos Christos , Mitrouli Marilena
Published: May 2021

Face recognition and identification are very important applications in machine learning. Due to the increasing amount of available data, traditional approaches based on matricization and matrix PCA methods can be difficult to implement. Moreover, the tensorial approaches are a natural choice, due to the mere structure of the databases, for example in the case of color images. Nevertheless, even though various authors proposed factorization strategies for tensors, the size of the considered tensors can pose some serious issues. Indeed, the most demanding part of the computational effort in recognition or identification problems resides in the training process. When only a few features are needed to construct the projection space, there is no need to compute a SVD on the whole data. Two versions of the tensor Golub–Kahan algorithm are considered in this manuscript, as an alternative to the classical use of the tensor SVD which is based on truncated strategies. In this paper, we consider the Tensor Tubal Golub–Kahan Principal Component Analysis method which purpose it to extract the main features of images using the tensor singular value decomposition (SVD) based on the tensor cosine product that uses the discrete cosine transform. This approach is applied for classification and face recognition and numerical tests show its effectiveness.
On Fourier Coefficients of the Symmetric Square L-Function at Piatetski-Shapiro Prime Twins
Authors: Han Xue , Yan Xiaofei , Zhang Deyu
Published: May 2021

Let Pc(x)={p≤x|p,[pc]areprimes},c∈R+∖N and λsym2f(n) be the n-th Fourier coefficient associated with the symmetric square L-function L(s,sym2f). For any A>0, we prove that the mean value of λsym2f(n) over Pc(x) is ≪xlog−A−2x for almost all c∈ε,(5+3)/8−ε in the sense of Lebesgue measure. Furthermore, it holds for all c∈(0,1) under the Riemann Hypothesis. Furthermore, we obtain that asymptotic formula for λf2(n) over Pc(x) is ∑p,qprimep≤x,q=[pc]λf2(p)=xclog2x(1+o(1)), for almost all c∈ε,(5+3)/8−ε, where λf(n) is the normalized n-th Fourier coefficient associated with a holomorphic cusp form f for the full modular group.
Recombinant Expression of Thrombolytic Agent Reteplase in Marine Microalga Tetraselmis subcordiformis (Chlorodendrales, Chlorophyta)
Authors: Wu Chunhui , Zheng Caiyun , Wang Jinxia , Jiang Peng
Published: May 2021

Tetraselmis subcordiformis, a unicellular marine green alga, is used widely in aquaculture as an initial feeding for fish, bivalve mollusks, penaeid shrimp larvae, and rotifers because of its rich content of amino acids and fatty acids. A stable nuclear transformation system using the herbicide phosphinothricin (PPT) as a selective reagent was established previously. In this research, the recombinant expression in T. subcordiformis was investigated by particle bombardment with the rt-PA gene that encodes the recombinant human tissue-type plasminogen activator (Reteplase), which is a thrombolytic agent for acute myocardial infarction treatment. Transgenic algal strains were selected by their resistance to PPT, and expression of rt-PA was validated by PCR, Southern blotting, and Western blotting, and bioactivity of rt-PA was confirmed by the fibrin agarose plate assay for bioactivity. The results showed that rt-PA was integrated into the genome of T. subcordiformis, and the expression product was bioactive, indicating proper post-transcriptional modification of rt-PA in T. subcordiformis. This report contributes to efforts that take advantage of marine microalgae as cell factories to prepare recombinant drugs and in establishing a characteristic pathway of oral administration in aquaculture.
Improving Microalgae Research and Marketing in the European Atlantic Area: Analysis of Major Gaps and Barriers Limiting Sector Development
Authors: Rumin Judith , Gonçalves de Oliveira Junior Raimundo , Bérard Jean-Baptiste , Picot Laurent
Published: May 2021

Microalgae and cyanobacteria represent a diverse renewable resource with significant potential for the industrial production of goods and services with high added value. However, scientific, technical/technological, legislative and market gaps and barriers still limit the growth of these markets in Europe and the number of exploited species. We conducted an in-depth survey of European microalgae researchers, experts and stakeholders to identify these limitations and to discuss strategies, recommendations and guidelines to overcome these barriers. Here, we present the findings of this study which detail the main promising markets for microalgae and cyanobacteria in the coming decades, an updated SWOT analysis of the sector, the current opportunities, limitations, risks and threats for microalgae research and market sectors in Europe, a traffic light analysis for a quick assessment of market opportunities for each microalgae sector and detailed recommendations/guidelines for overcoming the scientific, technical/technological, legislative and market gaps and barriers.
Risk Factors for Cerebral Palsy in Moldova
Authors: Bufteac Gincota Ecaterina , Jahnsen Reidun , Spinei Larisa , Andersen Guro L.
Published: May 2021

Background and Objectives: This is the first study assessing risk factors for cerebral palsy (CP) among children born in Moldova. The aim of this study was to identify and describe risk factors for cerebral palsy (CP) among children born in Moldova, which is one of the low-middle income countries in Europe. Materials and Methods: We identified 351 children with CP born during 2009 and 2010 in Moldova. Detailed information on 417 children without CP served as a reference group. Logistic regression analyses were applied to the calculate crude and adjusted odds ratios (OR) for CP with 95% confidence intervals (CI) in addition to attributable fraction (AF). Results: Among children with CP (40.5% girls), 26% had spastic unilateral, 54% bilateral, 13% dyskinetic, 5% ataxic and 2% unclassified CP. Significant risk factors for CP included maternal alcohol consumption during pregnancy (OR 1.7, p = 0.002), maternal hypertension (OR 2.0, p < 0.001), children born to mothers from the rural areas (OR 1.6, p < 0.001), maternal age ≥35 years (OR 0.6, p = 0.018), maternal epilepsy (OR 4.3, p < 0.001), breech delivery (OR 3.1, p = 0.001), home births (OR 6.3, p = 0.001), umbilical cord around neck (OR 2.2, p < 0.001), AVD (OR 3.1, p < 0.001), male gender (OR 1.3, p < 0.001), SGA (OR 1.3, p = 0.027), multiple gestations (OR 1.7, p < 0.001) and hyperbilirubinemia (OR 4.5, p < 0.001). Multivariable analyses showed that the AF of CP was 64% for rural residence (OR 2.8, p = 0.002), 87% for home birth (7.6, p = 0.005), 79% for pre-labor rupture of membrane (OR 4.9, p = 0.001), 66% for breech delivery (OR 2.9, p = 0.002) and 81% for hyperbilirubinemia (OR 5.4, p < 0.001). Conclusions: A combination of factors related to the mother, the delivery and the child were risk factors for CP in Moldova, many of them possibly avoidable. Improved pregnancy and maternity care would potentially reduce the risk of CP. A national CP registry in Moldova is suggested as an opportunity to follow up on these findings.
Medical School Education on Myalgic Encephalomyelitis
Authors: Muirhead Nina , Muirhead John , Lavery Grace , Marsh Ben
Published: May 2021

Background and objectives: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex multi-system disease with a significant impact on the quality of life of patients and their families, yet the majority of ME/CFS patients go unrecognised or undiagnosed. For two decades, the medical education establishment in the UK has been challenged to remedy these failings, but little has changed. Meanwhile, there has been an exponential increase in biomedical research and an international paradigm shift in the literature, which defines ME/CFS as a multisystem disease, replacing the psychogenic narrative. This study was designed to explore the current UK medical school education on ME/CFS and to identify challenges and opportunities relating to future ME/CFS medical education. Materials and methods: A questionnaire, developed under the guidance of the Medical Schools Council, was sent to all 34 UK medical schools to collect data for the academic year 2018–2019. Results: Responses were provided by 22 out of a total of 34 medical schools (65%); of these 13/22 (59%) taught ME/CFS, and teaching was led by lecturers from ten medical specialties. Teaching delivery was usually by lecture; discussion, case studies and e-learning were also used. Questions on ME/CFS were included by seven schools in their examinations and three schools reported likely clinical exposure to ME/CFS patients. Two-thirds of respondents were interested in receiving further teaching aids in ME/CFS. None of the schools shared details of their teaching syllabus, so it was not possible to ascertain what the students were being taught. Conclusions: This exploratory study reveals inadequacies in medical school teaching on ME/CFS. Many medical schools (64% of respondents) acknowledge the need to update ME/CFS education by expressing an appetite for further educational materials. The General Medical Council (GMC) and Medical Schools Council (MSC) are called upon to use their considerable influence to bring about the appropriate changes to medical school curricula so future doctors can recognise, diagnose and treat ME/CFS. The GMC is urged to consider creating a registered specialty encompassing ME/CFS, post-viral fatigue and long Covid.
Immune Modulation in Critically Ill Septic Patients
Authors: Cutuli Salvatore Lucio , Carelli Simone , Grieco Domenico Luca , De Pascale Gennaro
Published: May 2021

Sepsis is triggered by infection-induced immune alteration and may be theoretically improved by pharmacological and extracorporeal immune modulating therapies. Pharmacological immune modulation may have long lasting clinical effects, that may even worsen patient-related outcomes. On the other hand, extracorporeal immune modulation allows short-term removal of inflammatory mediators from the bloodstream. Although such therapies have been widely used in clinical practice, the role of immune modulation in critically ill septic patients remains unclear and little evidence supports the role of immune modulation in this clinical context. Accordingly, further research should be carried out by an evidence-based and personalized approach in order to improve the management of critically ill septic patients.
Silica Fouling in Reverse Osmosis Systems–Operando Small-Angle Neutron Scattering Studies
Authors: Pipich Vitaliy , Starc Thomas , Buitenhuis Johan , Kasher Roni , Petry Winfried , Oren Yoram , Schwahn Dietmar
Published: May 2021

We present operando small-angle neutron scattering (SANS) experiments on silica fouling at two reverse osmose (RO) membranes under almost realistic conditions of practiced RO desalination technique. To its realization, two cells were designed for pressure fields and tangential feed cross-flows up to 50 bar and 36 L/h, one cell equipped with the membrane and the other one as an empty cell to measure the feed solution in parallel far from the membrane. We studied several aqueous silica dispersions combining the parameters of colloidal radius, volume fraction, and ionic strength. A relevant result is the observation of Bragg diffraction as part of the SANS scattering pattern, representing a crystalline cake layer of simple cubic lattice structure. Other relevant parameters are silica colloidal size and volume fraction far from and above the membrane, as well as the lattice parameter of the silica cake layer, its volume fraction, thickness, and porosity in comparison with the corresponding permeate flux. The experiments show that the formation of cake layer depends to a large extent on colloidal size, ionic strength and cross-flow. Cake layer formation proved to be a reversible process, which could be dissolved at larger cross-flow. Only in one case we observed an irreversible cake layer formation showing the characteristics of an unstable phase transition. We likewise observed enhanced silica concentration and/or cake formation above the membrane, giving indication of a first order liquid–solid phase transformation.
Extracorporeal Membrane Oxygenation Use in Thoracic Surgery
Authors: Suk Pavel , Šrámek Vladimír , Čundrle Ivan
Published: May 2021

This narrative review is focused on the application of extracorporeal membrane oxygenation (ECMO) in thoracic surgery, exclusive of lung transplantation. Although the use of ECMO in this indication is still rare, it allows surgery to be performed in patients where conventional ventilation is not feasible—especially in single lung patients, sleeve lobectomy or pneumonectomy and tracheal or carinal reconstructions. Comparisons with other techniques, various ECMO configurations, the management of anticoagulation, anesthesia, hypoxemia during surgery and the use of ECMO in case of postoperative respiratory failure are reviewed and supported by two cases of perioperative ECMO use, and an overview of published case series.
What Does HR Manage? Workforce Measurement and Control
Authors: Clardy Alan
Published: May 2021

According to the long-standing axiom of management, one cannot manage what cannot be measured. Two questions emerge that are applicable to the Human Resource (HR) function. What does it manage? What should it measure? Prior answers recommend that HR should manage its functional activities, the organization’s human capital, or certain strategically important factors in a balanced scorecare, none of which are fully satisfactory. This paper argues that the HR function should manage the organization’s workforce. To do that, one must measure aspects of that workforce. This paper provides a generic framework of measures for that purpose. The foundation measures focus on the structure of jobs in the organization, the demographic characteristics of the workforce, their attitudes, the flow of personnel, and certain moderating variables. Measures for special segments of the workforce, such as sales and service personnel and leaders, are also noted.
High Temperature Behavior of Al-7Si-0.4Mg Alloy with Er and Zr Additions
Authors: Gariboldi Elisabetta , Confalonieri Chiara , Colombo Marco
Published: May 2021

In recent years, many efforts have been devoted to the development of innovative Al-based casting alloys with improved high temperature strength. Research is often oriented to the investigation of the effects of minor element additions to widely diffused casting alloys. The present study focuses on Al-7Si-0.4Mg (A356) alloy with small additions of Er and Zr. Following previous scientific works on the optimization of heat treatment and on tensile strength, creep tests were carried out at 300 °C under applied stress of 30 MPa, a reference condition for creep characterization of innovative high-temperature Al alloys. The alloys containing both Er and Zr displayed a lower minimum creep strain rate and a longer time to rupture. Fractographic and microstructural analyses on crept and aged specimens were performed to understand the role played by eutectic silicon, by the coarse intermetallics and by α-Al matrix ductility. The creep behavior in tension of the three alloys has been discussed by comparing them to tension and compression creep curves available in the literature for Al-7Si-0.4Mg improved by minor elemental additions.
Corrosion Behavior of L245N Standard Steel in CO2 Saturated Brine under Flow Condition
Authors: Hu Ying , Xin Long , Liu Tingguang , Lu Yonghao
Published: May 2021

The corrosion behavior of oilfield used L245N standard steel was tested in simulated oilfield solution by dynamic high-temperature autoclave. The corrosion products were characterized by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Electrochemical impedance spectroscopy (EIS) respectively. In addition, the corrosion rates and surface morphological characteristics of the steels after different exposure times were studied. The results showed that the corrosion rate decreased sharply and then increased with time in the high salinity flow solution, which was related to the formation of corrosion scale and the remaining cementite within it. At the beginning of the exposure time, the formed corrosion scale became thicker, resulting in a significant decrease of the corrosion rate. While with increasing time, on the one hand, the increased remaining cementite within corrosion scale facilitated the corrosion by the galvanic corrosion between the remaining cementite and the ferrite within the metal. On the other hand, the protective effect of corrosion scale formed on the remaining cementite skeleton declined due to the formation of large amounts of FexCa1−xCO3, which also promoted the corrosion rate of the steels, both these ways contributed to a slow increase of corrosion rate.
Characteristics of Microstructure Evolution during FAST Joining of the Tungsten Foil Laminate
Authors: Tan Xiaoyue , Wang Wujie , Chen Xiang , Mao Yiran , Litnovsky Andrey , Klein Felix , Bittner Pawel , Coenen Jan Willem , Linsmeier Christian , Liu Jiaqin , Luo Laima , Wu Yucheng
Published: May 2021

The tungsten (W) foil laminate is an advanced material concept developed as a solution for the low temperature brittleness of W. However, the deformed W foils inevitably undergo microstructure deterioration (crystallization) during the joining process at a high temperature. In this work, joining of the W foil laminate was carried out in a field-assisted sintering technology (FAST) apparatus. The joining temperature was optimized by varying the temperature from 600 to 1400 °C. The critical current for mitigating the microstructure deterioration of the deformed W foil was evaluated by changing the sample size. It is found that the optimal joining temperature is 1200 °C and the critical current density is below 418 A/cm2. According to an optimized FAST joining process, the W foil laminate with a low microstructure deterioration and good interfacial bonding can be obtained. After analyzing these current profiles, it was evident that the high current density (sharp peak current) is the reason for the significant microstructure deterioration. An effective approach of using an artificial operation mode was proposed to avoid the sharp peak current. This study provides the fundamental knowledge of FAST principal parameters for producing advanced materials.
Understanding the Links between the Composition-Processing-Properties in New Formulations of HEAs Sintered by SPS
Authors: Alvaredo-Olmos Paula , Molina-Aldareguía Jon , Vaz-Romero Alvaro , Prieto Estela , González-Julián Jesús , Monclús Miguel Alberto
Published: May 2021

This work presents two new compositions of high entropy alloys (HEAs) that were designed with the aim of obtaining a body-centered cubic (BCC) phase with high hardness values and a moderate density. Sintering was performed using Spark Plasma Sintering (SPS) with different heating rates to determine the influence of the processing parameters on the phase formation. The microstructural study revealed that the presence of Ni in the composition promoted phase separation, and the mechanical study confirmed a clear influence on the mechanical properties of both the composition and heating rate. The combination of microscopy with compression and nanoindentation tests at room and high temperature made it possible to advance our understanding of the relationships between the composition, processing, and properties of this emerging group of alloys.
Multi-Objective Optimization of Process Parameters to Enhance Efficiency in the Shoe-Type Centerless Grinding Operation for Internal Raceway of Ball Bearings
Authors: Tuan Nguyen Anh
Published: May 2021

In this article, new research on the multi-objective optimization of the process parameters applied to enhance the efficiency in the shoe-type centerless grinding operation for the inner ring raceway of the ball bearing made from SUJ2 alloy steel is presented. The four important input parameters for this process, which included the normal feed rate of fine grinding (Snf), the speed of the workpiece (Vw), the cutting depth of fine grinding (af), and the number of ground parts (Np), were investigated. The aim of the study was to find the most appropriate value set of process parameters in order to, simultaneously minimize the grindstone wear (Gw), maximize the material removal rate (MRR) and the total number of ground parts in a grinding cycle (N’p), while guaranteeing other technology requirements such as surface roughness Ra ≤ 0.5 (µm), oval level Op ≤ 3 (µm), etc. In order to solve the problem, based on the experimental data, in which the grindstone wear was measured online by a measuring system consisting of two pneumatic probes, the optimization of the target functions of Gw, N’p, and MRR and mathematical models that express the dependencies of outcome parameters Gw, Ra, Op, MRR, etc. on the process parameters were determined. Therefore, a global optimal solution of such a discrete and nonlinear multi-objective optimization problem was solved by using a genetic algorithm, presenting the most appropriate process parameters as follows: Snf = 15.38 (µm/s), Vw = 6.00 (m/min), af = 11.76 (µm), and Np = 20 (parts/cycle). In addition, the impact of the four process parameters (Snf, Vw, af, Np) on the wear of the grinding wheel (Gw), the oval level of parts (Op), and the surface roughness of parts (Ra) was evaluated. The discovered technology mode has been applied to the real machining process for the inner ring raceway of the 6208_ball bearing made from SUJ2 alloy steel, and the outcome showed a much better result in comparison with default setting modes, while still ensuring the technology requirements. The difference between the predicted values and the real values of the parameters Gw, Ra, Op, and MRR were controlled within 5% of the ranges.
Synthesis of θ-Al2O3 Whiskers with Twins
Authors: Liao Nan , Su Xiaojia , Zhang Haiwen , Feng Qingguo , Grasso Salvatore , Hu Chunfeng
Published: May 2021

In this work, θ-Al2O3 whiskers with twins were successfully fabricated by a hydrothermal method followed by annealing at 1000 °C in argon atmosphere using Al2(SO4)3·18H2O, CO(NH2)2 and PEG2000 as initial materials. It is confirmed that precursor of AlO(OH) whiskers is suitable to be used for preparing alumina whiskers when the molar ratio of Al3+:CO(NH2)2 is selected to be 1:6. The mean length of obtained whiskers is 1.5 μm and the average width is 0.1 μm. Interestingly, it is found that the as-prepared θ-Al2O3 whiskers consist of twins with (100) plane as the twin surface, which is ascribed to the phase transformation from tetragonal phase (δ-Al2O3) to monoclinic phase (θ-Al2O3) during the annealing. Additionally, the specific surface area of θ-Al2O3 whiskers is measured to be 38.2 m2/g.
Dysregulated Metabolites Serve as Novel Biomarkers for Metabolic Diseases Caused by E-Cigarette Vaping and Cigarette Smoking
Authors: Wang Qixin , Ji Xiangming , Rahman Irfan
Published: May 2021

Metabolites are essential intermediate products in metabolism, and metabolism dysregulation indicates different types of diseases. Previous studies have shown that cigarette smoke dysregulated metabolites; however, limited information is available with electronic cigarette (e-cig) vaping. We hypothesized that e-cig vaping and cigarette smoking alters systemic metabolites, and we propose to understand the specific metabolic signature between e-cig users and cigarette smokers. Plasma from non-smoker controls, cigarette smokers, and e-cig users was collected, and metabolites were identified by UPLC-MS (ultra-performance liquid chromatography mass spectrometer). Nicotine degradation was activated by e-cig vaping and cigarette smoking with increased concentrations of cotinine, cotinine N-oxide, (S)-nicotine, and (R)-6-hydroxynicotine. Additionally, we found significantly decreased concentrations in metabolites associated with tricarboxylic acid (TCA) cycle pathways in e-cig users versus cigarette smokers, such as d-glucose, (2R,3S)-2,3-dimethylmalate, (R)-2-hydroxyglutarate, O-phosphoethanolamine, malathion, d-threo-isocitrate, malic acid, and 4-acetamidobutanoic acid. Cigarette smoking significant upregulated sphingolipid metabolites, such as d-sphingosine, ceramide, N-(octadecanoyl)-sphing-4-enine, N-(9Z-octadecenoyl)-sphing-4-enine, and N-[(13Z)-docosenoyl]-sphingosine, versus e-cig vaping. Overall, e-cig vaping dysregulated TCA cycle-related metabolites while cigarette smoking altered sphingolipid metabolites. Both e-cig and cigarette smoke increased nicotinic metabolites. Therefore, specific metabolic signatures altered by e-cig vaping and cigarette smoking could serve as potential systemic biomarkers for early pathogenesis of cardiopulmonary diseases.
Metabolomics in the Identification of Biomarkers of Asthma
Authors: Villaseñor Alma , Eguiluz-Gracia Ibon , Moreira André , Wheelock Craig E. , Escribese María M
Published: May 2021

Asthma is a major non-communicable disease characterized by recurrent attacks of breathlessness and wheezing [...]
LC-MS Based Platform Simplifies Access to Metabolomics for Peroxisomal Disorders
Authors: Klemp Henry Gerd , Kettwig Matthias , Streit Frank , Gärtner Jutta , Rosewich Hendrik , Krätzner Ralph
Published: May 2021

Peroxisomes are central hubs for cell metabolism and their dysfunction is linked to devastating human disorders, such as peroxisomal biogenesis disorders and single peroxisomal enzyme/protein deficiencies. For decades, biochemical diagnostics have been carried out using classical markers such as very long-chain fatty acids (VLCFA), which can be inconspicuous in milder and atypical cases. Holistic metabolomics studies revealed several potentially new biomarkers for peroxisomal disorders for advanced laboratory diagnostics including atypical cases. However, establishing these new markers is a major challenge in routine diagnostic laboratories. We therefore investigated whether the commercially available AbsoluteIDQ p180 kit (Biocrates Lifesciences), which utilizes flow injection and liquid chromatography mass spectrometry, may be used to reproduce some key results from previous global metabolomics studies. We applied it to serum samples from patients with mutations in peroxisomal target genes PEX1, ABCD1, and the HSD17B4 gene. Here we found various changes in sphingomyelins and lysophosphatidylcholines. In conclusion, this kit can be used to carry out extended diagnostics for peroxisomal disorders in routine laboratories, even without access to a metabolomics unit.
Analysis of Sirtuin 1 and Sirtuin 3 at Enzyme and Protein Levels in Human Breast Milk during the Neonatal Period
Authors: Hase Kristina , Stahmer Laura , Shammas Hadeel , Peter Corinna , Bohnhorst Bettina , Das Anibh Martin
Published: May 2021

Breast feeding is regarded as the preferred nutrition modality for children during the first few months of life. It not only furthers growth and development but also is supposed to impact later life. The first 1000 days are regarded as a critical window for development, even beyond infancy. The physiological basis underlying this beneficial effect is not clear. Sirtuins are important regulatory proteins of metabolism and are supposed to play a critical role in ageing and longevity as well as in diseases. In the present study, we developed novel methods to assay sirtuin 1 and sirtuin 3 at enzyme activity (via fluorometry) and protein levels (by Western blot) in the aqueous phase and in the cell pellet of human breast milk and assessed the impact of ongoing lactation during the neonatal period. Sirtuin activities in the aqueous phase were negatively correlated with the duration of lactation in the neonatal period. There was no correlation of sirtuin activities in the cell pellet with the duration of lactation. The amounts of sirtuin 1 and sirtuin 3 measured by Western blot were negatively correlated with the lactation period.
In Situ Vitrification of Lung Cancer Organoids on a Microwell Array
Authors: Liu Qiang , Zhao Tian , Wang Xianning , Chen Zhongyao , Hu Yawei , Chen Xiaofang
Published: May 2021

Three-dimensional cultured patient-derived cancer organoids (PDOs) represent a powerful tool for anti-cancer drug development due to their similarity to the in vivo tumor tissues. However, the culture and manipulation of PDOs is more difficult than 2D cultured cell lines due to the presence of the culture matrix and the 3D feature of the organoids. In our other study, we established a method for lung cancer organoid (LCO)-based drug sensitivity tests on the superhydrophobic microwell array chip (SMAR-chip). Here, we describe a novel in situ cryopreservation technology on the SMAR-chip to preserve the viability of the organoids for future drug sensitivity tests. We compared two cryopreservation approaches (slow freezing and vitrification) and demonstrated that vitrification performed better at preserving the viability of LCOs. Next, we developed a simple procedure for in situ cryopreservation and thawing of the LCOs on the SMAR-chip. We proved that the on-chip cryopreserved organoids can be recovered successfully and, more importantly, showing similar responses to anti-cancer drugs as the unfrozen controls. This in situ vitrification technology eliminated the harvesting and centrifugation steps in conventional cryopreservation, making the whole freeze–thaw process easier to perform and the preserved LCOs ready to be used for the subsequent drug sensitivity test.
A Piezoelectric and Electromagnetic Hybrid Galloping Energy Harvester with the Magnet Embedded in the Bluff Body
Authors: Li Xia , Bi Cheng , Li Zhiyuan , Liu Benxue , Wang Tingting , Zhang Sanchuan
Published: May 2021

To meet the needs of low-power microelectronic devices for on-site self-supply energy, a galloping piezoelectric–electromagnetic energy harvester (GPEEH) is proposed. It consists of a galloping piezoelectric energy harvester (GPEH) and an electromagnetic energy harvester (EEH), which is installed inside the bluff body of the GPEH. The vibration at the end of the GPEH cantilever drives the magnet to vibrate, so that electromagnetic energy can be captured by cutting off the induced magnetic field lines. The coupling structure is a two-degree-of-freedom motion, which improves the output power of the energy harvester. Based on Hamilton’s variational principle and quasi-static hypothesis, the piezoelectric–electromagnetic vibrated coupling equation is established, and the output characteristics of GPEEH are obtained by the method of numerical simulation. Using the method of numerical simulation, studies a series of parameters on the output performance. when the wind speed is 9 m/s, the effective output power of the GPEEH is compared with the classical galloping piezoelectric energy harvester (CGPEH) who is no magnet. It is found that the output power of GPEEH 121% higher than the output power of CGPEH. Finally, set up an experimental platform, and test and verify. The experimental analysis results show that the simulated output parameter curves are basically consistent with the experimental drawing curves. In addition, when the wind speed is 9 m/s, under the same parameters, the effective output power of the GPEEH is 112.5% higher than that of the CGPEH. The correctness of the model is verified.
Dry Film Resist Laminated Microfluidic System for Electrical Impedance Measurements
Authors: Cao Yuan , Floehr Julia , Ingebrandt Sven , Schnakenberg Uwe
Published: May 2021

In micro-electrical-mechanical systems (MEMS), thick structures with high aspect ratios are often required. Dry film photoresist (DFR) in various thicknesses can be easily laminated and patterned using standard UV lithography. Here, we present a three-level DFR lamination process of SUEX for a microfluidic chip with embedded, vertically arranged microelectrodes for electrical impedance measurements. To trap and fix the object under test to the electrodes, an aperture is formed in the center of the ring-shaped electrodes in combination with a microfluidic suction channel underneath. In a proof-of-concept, the setup is characterized by electrical impedance measurements with polystyrene and ZrO2 spheres. The electrical impedance is most sensitive at approximately 2 kHz, and its magnitudes reveal around 200% higher values when a sphere is trapped. The magnitude values depend on the sizes of the spheres. Electrical equivalent circuits are applied to simulate the experimental results with a close match.
Innovative Implementation of an Alternative Tetrathiafulvene Derivative for Flexible Indium Phthalocyanine Chloride-Based Solar Cells
Authors: Hamui Leon , Sánchez-Vergara María Elena
Published: May 2021

Herein, we present the photovoltaic properties of an indium phthalocyanine chloride (InClPc)-based flexible planar heterojunction device, introducing the tetrathiafulvene derivative 4,4′-Dimethyl-5,5′-diphenyltetrathiafulvalene (DMDP-TTF) as the electron donor layer. UV-vis spectroscopy is widely used to characterize the electronic behavior of the InClPc/DMDP-TTF active layer. The interactions between the DMDP-TTF and phthalocyanine are predominantly intermolecular and the result of the aggregation of InClPc. Tauc bands were obtained at 1.41 and 2.8 eV; these energy peaks can result in a charge transfer ascribed to the transition from the DMDP-TTF to π-orbitals that are associated with the phthalocyanine ring or even with the same indium metal center. Conductive carbon (CC) was used for the cathode. Finally, an indium tin oxide (ITO)/InClPc/DMDP-TTF/CC device was fabricated by high-vacuum thermal evaporation onto a flexible substrate and the photovoltaic properties were evaluated. A diode type I-V curve behavior was observed with a photovoltaic response under illumination. A generated photocurrent of 2.25 × 10−2 A/cm2 was measured. A conductivity reduction with the incident photon energy from 1.61 × 10−7 S/cm to 1.43 × 10−7 S/cm is observed. The diode resistance presents two different behaviors with the applied voltage. A VTFL of 5.39 V, trap concentration of 7.74 × 1016 cm−3, and carrier mobility values of ~10−6 cm2/V s were calculated, showing improved characteristics via the innovative implementation of an alternative TTF-derivative, indicating that the DMDP-TTF has a strong interaction at the junction where free available states are increased, thus inducing higher mobilities due to the large number of π-orbitals, which indicates the feasibility of its use in solar cells technology.
Self-Assembled Monolayers of Alkanethiols on Nickel Insert: Characterization of Friction and Analysis on Demolding Quality in Microinjection Molding
Authors: Chen Jiachen , Yang Jin , Zhou Mingyong , Weng Can
Published: May 2021

When the part geometry scaling down from macro to microscale level, the size-induced surface effect becomes significant in the injection molding process. The adhesion between polymer and nickel (Ni) mold insert during the process can lead to defects in necking, warping and deformation of microstructure. In this study, the self-assembled monolayers (SAMs) with low surface energy were deposited on the Ni surface to reduce the adhesion and further improve the demolding quality of the microstructure. Results show that the alkyl mercaptan SAMs with chemical bonds and close alignment can be successfully deposited on the surface of Ni by the solution deposition method. The contact angle, surface free energy, and friction coefficient before and after anti-adhesion treatment on the surface of mold insert were measured. In addition, the anti-adhesion properties of different alkyl mercaptan materials and the correspondingly replication quality of microstructure parts after injection molding were analyzed. It is found that the Ni mold insert treated by the perfluorodecanethiol has the best wear resistance and still shows good reproducibility at the 100th demolding cycle.
The Effect of Nitrogen Incorporation on the Optical Properties of Si-Rich a-SiCx Films Deposited by VHF PECVD
Authors: Li Hongliang , Lin Zewen , Guo Yanqing , Song Jie , Huang Rui , Lin Zhenxu
Published: May 2021

The influence of N incorporation on the optical properties of Si-rich a-SiCx films deposited by very high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) was investigated. The increase in N content in the films was found to cause a remarkable enhancement in photoluminescence (PL). Relative to the sample without N incorporation, the sample incorporated with 33% N showed a 22-fold improvement in PL. As the N content increased, the PL band gradually blueshifted from the near-infrared to the blue region, and the optical bandgap increased from 2.3 eV to 5.0 eV. The enhancement of PL was suggested mainly from the effective passivation of N to the nonradiative recombination centers in the samples. Given the strong PL and wide bandgap of the N incorporated samples, they were used to further design an anti-counterfeiting label.
A Magnetorheological Fluids-Based Robot-Assisted Catheter/Guidewire Surgery System for Endovascular Catheterization
Authors: Zhang Linshuai , Gu Shuoxin , Guo Shuxiang , Tamiya Takashi
Published: May 2021

A teleoperated robotic catheter operating system is a solution to avoid occupational hazards caused by repeated exposure radiation of the surgeon to X-ray during the endovascular procedures. However, inadequate force feedback and collision detection while teleoperating surgical tools elevate the risk of endovascular procedures. Moreover, surgeons cannot control the force of the catheter/guidewire within a proper range, and thus the risk of blood vessel damage will increase. In this paper, a magnetorheological fluid (MR)-based robot-assisted catheter/guidewire surgery system has been developed, which uses the surgeon’s natural manipulation skills acquired through experience and uses haptic cues to generate collision detection to ensure surgical safety. We present tests for the performance evaluation regarding the teleoperation, the force measurement, and the collision detection with haptic cues. Results show that the system can track the desired position of the surgical tool and detect the relevant force event at the catheter. In addition, this method can more readily enable surgeons to distinguish whether the proximal force exceeds or meets the safety threshold of blood vessels.
Fabrication of Graphene Nanomesh FET Terahertz Detector
Authors: Zhai Yuan , Xiang Yi , Yuan Weiqing , Chen Gang , Shi Jinliang , Liang Gaofeng , Wen Zhongquan , Wu Ying
Published: May 2021

High sensitivity detection of terahertz waves can be achieved with a graphene nanomesh as grating to improve the coupling efficiency of the incident terahertz waves and using a graphene nanostructure energy gap to enhance the excitation of plasmon. Herein, the fabrication process of the FET THz detector based on the rectangular GNM (r-GNM) is designed, and the THz detector is developed, including the CVD growth and the wet-process transfer of high quality monolayer graphene films, preparation of r-GNM by electron-beam lithography and oxygen plasma etching, and the fabrication of the gate electrodes on the Si3N4 dielectric layer. The problem that the conductive metal is easy to peel off during the fabrication process of the GNM THz device is mainly discussed. The photoelectric performance of the detector was tested at room temperature. The experimental results show that the sensitivity of the detector is 2.5 A/W (@ 3 THz) at room temperature.
Salmonella Bacterin Vaccination Decreases Shedding and Colonization of Salmonella Typhimurium in Pigs
Authors: Moura Eduarda Alexandra Gonçalves de Oliveira , Silva Daniela Gomes da , Turco Caio Henrique , Sanches Thainara Vitoria Carnevalli , Storino Gabriel Yuri , Almeida Henrique Meiroz de Souza , Mechler-Dreibi Marina Lopes , Rabelo Isabela Peixoto , Sonalio Karina , Oliveira Luís Guilherme de
Published: May 2021

Since the occurrence of swine salmonellosis has increased over time and control strategies other than biosecurity are highly recommended, the present study aimed to evaluate the efficacy of vaccination with Salmonella Choleraesuis and Salmonella Typhimurium bacterins in pigs. Two experimental groups were formed: G1, animals immunized with two doses of a commercial vaccine (n = 20); G2, control group (n = 20). After vaccination, all pigs were orally challenged (D0) with 108 CFU of Salmonella Typhimurium and evaluated for 40 days. Every 10 days after D0, five piglets from each experimental group were euthanized and submitted to the necroscopic examination, when organ samples were collected. Blood samples and rectal swabs were collected before the first dose of the vaccine (D−42), before the second dose (D−21), before the challenge (D0), and thereafter, every three days until D39. Blood count, serum IgG measurement by ELISA, and the excretion of Salmonella Typhimurium in feces were evaluated. While the results from blood count and serum IgG concentration did not differ, the detection and excretion of Salmonella between G1 and G2 differed (p < 0.05). Therefore, it was observed that this vaccine partially protected the animals against experimental infection with Salmonella Typhimurium, reducing the excretion of bacteria in feces.
Studying Microbial Communities through Co-Occurrence Network Analyses during Processes of Waste Treatment and in Organically Amended Soils: A Review
Authors: Siles José A. , García-Sánchez Mercedes , Gómez-Brandón María
Published: May 2021

Organic wastes have the potential to be used as soil organic amendments after undergoing a process of stabilization such as composting or as a resource of renewable energy by anaerobic digestion (AD). Both composting and AD are well-known, eco-friendly approaches to eliminate and recycle massive amounts of wastes. Likewise, the application of compost amendments and digestate (the by-product resulting from AD) has been proposed as an effective way of improving soil fertility. The study of microbial communities involved in these waste treatment processes, as well as in organically amended soils, is key in promoting waste resource efficiency and deciphering the features that characterize microbial communities under improved soil fertility conditions. To move beyond the classical analyses of metataxonomic data, the application of co-occurrence network approaches has shown to be useful to gain insights into the interactions among the members of a microbial community, to identify its keystone members and modelling the environmental factors that drive microbial network patterns. Here, we provide an overview of essential concepts for the interpretation and construction of co-occurrence networks and review the features of microbial co-occurrence networks during the processes of composting and AD and following the application of the respective end products (compost and digestate) into soil.
Identification of Homologous Polyprenols from Thermophilic Bacteria
Authors: Gharwalová Lucia , Palyzová Andrea , Marešová Helena , Kolouchová Irena , Kyselová Lucie , Řezanka Tomáš
Published: May 2021

Sixteen strains of five genera of thermophilic bacteria, i.e., Alicyclobacillus, Brevibacillus, Geobacillus, Meiothermus, and Thermus, were cultivated at a temperature from 42 to 70 °C. Twelve strains were obtained from the Czech Collection of Microorganisms, while four were directly isolated and identified by 16S rRNA gene sequencing from the hot springs of the world-famous Carlsbad spa (Czech Republic). Polyprenol homologs from C40 to C65 as well as free undecaprenol (C55), undecaprenyl phosphate, and undecaprenyl diphosphate were identified by shotgun analysis and RP-HPLC/MS-ESI+ (reverse phase high-performance liquid chromatography–high-resolution positive electrospray ionization mass spectrometry). The limit of detection (50 pM) was determined for individual homologs and free polyprenols and their phosphates. Thus, it has been shown that at least some thermophilic bacteria produce not just the major C55 polyprenol as previously described, but a mixture of homologs.
Further Studies on the 3-Ketosteroid 9α-Hydroxylase of Rhodococcus ruber Chol-4, a Rieske Oxygenase of the Steroid Degradation Pathway
Authors: Baldanta Sara , Navarro Llorens Juana María , Guevara Govinda
Published: May 2021

The biochemistry and genetics of the bacterial steroid catabolism have been extensively studied during the last years and their findings have been essential to the development of biotechnological applications. For instance, metabolic engineering of the steroid-eater strains has allowed to obtain intermediaries of industrial value. However, there are still some drawbacks that must be overcome, such as the redundancy of the steroid catabolism genes in the genome and a better knowledge of its genetic regulation. KshABs and KstDs are key enzymes involved in the aerobic breakage of the steroid nucleus. Rhodococcus ruber Chol-4 contains three kshAs genes, a single kshB gene and three kstDs genes within its genome. In the present work, the growth of R. ruber ΔkshA strains was evaluated on different steroids substrates; the promoter regions of these genes were analyzed; and their expression was followed by qRT-PCR in both wild type and ksh mutants. Additionally, the transcription level of the kstDs genes was studied in the ksh mutants. The results show that KshA2B and KshA1B are involved in AD metabolism, while KshA3B and KshA1B contribute to the cholesterol metabolism in R. ruber. In the kshA single mutants, expression of the remaining kshA and kstD genes is re-organized to survive on the steroid substrate. These data give insight into the fine regulation of steroid genes when several isoforms are present.
Experimental Assessment of Possible Factors Associated with Tick-Borne Encephalitis Vaccine Failure
Authors: Tuchynskaya Ksenia , Volok Viktor , Illarionova Victoria , Okhezin Egor , Polienko Alexandra , Belova Oxana , Rogova Anastasia , Chernokhaeva Liubov , Karganova Galina
Published: May 2021

Currently the only effective measure against tick-borne encephalitis (TBE) is vaccination. Despite the high efficacy of approved vaccines against TBE, rare cases of vaccine failures are well documented. Both host- and virus-related factors can account for such failures. In this work, we studied the influence of mouse strain and sex and the effects of cyclophosphamide-induced immunosuppression on the efficacy of an inactivated TBE vaccine. We also investigated how an increased proportion of non-infectious particles in the challenge TBE virus would affect the protectivity of the vaccine. The vaccine efficacy was assessed by mortality, morbidity, levels of viral RNA in the brain of surviving mice, and neutralizing antibody (NAb) titers against the vaccine strain and the challenge virus. Two-dose vaccination protected most animals against TBE symptoms and death, and protectivity depended on strain and sex of mice. Immunosuppression decreased the vaccine efficacy in a dose-dependent manner and changed the vaccine-induced NAb spectrum. The vaccination protected mice against TBE virus neuroinvasion and persistence. However, viral RNA was detected in the brain of some asymptomatic animals at 21 and 42 dpi. Challenge with TBE virus enriched with non-infectious particles led to lower NAb titers in vaccinated mice after the challenge but did not affect the protective efficacy.