bluuebunny/crossref_metadata_2025 huggingface dataset:
Multifunctional Therapeutic Potential of Phytocomplexes and Natural Extracts for Antimicrobial Properties
Authors: Rahman Md. Mominur , Rahaman Md. Saidur , Islam Md. Rezaul , Hossain Md. Emon , Mannan Mithi Faria , Ahmed Muniruddin , Saldías Marianela , Akkol Esra Küpeli , Sobarzo-Sánchez Eduardo
Published: September 2021

Natural products have been known for their antimicrobial factors since time immemorial. Infectious diseases are a worldwide burden that have been deteriorating because of the improvement of species impervious to various anti-infection agents. Hence, the distinguishing proof of antimicrobial specialists with high-power dynamic against MDR microorganisms is central to conquer this issue. Successful treatment of infection involves the improvement of new drugs or some common source of novel medications. Numerous naturally occurring antimicrobial agents can be of plant origin, animal origin, microbial origin, etc. Many plant and animal products have antimicrobial activities due to various active principles, secondary metabolites, or phytochemicals like alkaloids, tannins, terpenoids, essential oils, flavonoids, lectins, phagocytic cells, and many other organic constituents. Phytocomplexes’ antimicrobial movement frequently results from a few particles acting in cooperative energy, and the clinical impacts might be because of the direct effects against microorganisms. The restorative plants that may furnish novel medication lead the antimicrobial movement. The purpose of this study is to investigate the antimicrobial properties of the phytocomplexes and natural extracts of the plants that are ordinarily being utilized as conventional medications and then recommended the chance of utilizing them in drugs for the treatment of multiple drug-resistant disease.
Oleanolic Acid Nanofibers Attenuated Particulate Matter-Induced Oxidative Stress in Keratinocytes
Authors: Fu Hsuan , Yen Feng-Lin , Huang Pao-Hsien , Yang Chun-Yin , Yen Chia-Hung
Published: September 2021

Airborne particulate matter (PM) is one of the indicators of air pollution, and it is also the main factor causing oxidative stress in the skin. Oleanolic acid (OA), a natural terpenoid compound, effectively inhibited PM-induced skin aging; however, OA has poor water solubility and skin absorption, which limit its application in medicines and cosmetics. The aim of this study was to prepare oleanolic acid nanofibers (OAnf) and evaluate the effects of OA and OAnf in PM-treated keratinocytes. The results showed that OA dissolved in dissolved in dimethyl sulfoxide (DMSO) attenuated PM-induced reactive oxygen species overproduction, stress-activated protein kinase/Jun-amino-terminal kinase (SAPK/JNK) activation, and the expressions of inflammatory and skin-aging-related proteins. In addition, the nanofiber process of OA effectively improved the water solubility of OA more than 99,000-fold through changing its physicochemical properties, including a surface area increase, particle size reduction, amorphous transformation, and hydrogen bonding formation with excipients. The skin penetration ability of OAnf was consistently over 10-fold higher than that of OA. Moreover, when dissolved in PBS, OAnf displayed superior antioxidant, anti-inflammatory, and anti-skin aging activities in PM-treated keratinocytes than OA. In conclusion, our findings suggest that OAnf could be a topical antioxidant formulation to attenuate skin problems caused by PM.
Fruit of Gardenia jasminoides Induces Mitochondrial Activation and Non-Shivering Thermogenesis through Regulation of PPARγ
Authors: Park Woo Yong , Song Gahee , Park Ja Yeon , Kim Kwan-Il , Ahn Kwang Seok , Kwak Hyun Jeong , Leem Jungtae , Um Jae-Young , Park Jinbong
Published: September 2021

The extract of the Gardenia jasminoides fruit (GJFE) can been consumed as an herbal tea or used as a yellow dye. Recently, studies report that GFJE exerts inhibitory effects on lipid accumulation and adipogenesis in white adipocytes. We evaluated the thermogenic actions of GJFE by focusing on mitochondrial activation and studying the underlying mechanisms. To investigate the role of GJFE on thermogenesis in mice, we used an acute cold exposure model. After 2 weeks of feeding, the cold tolerance of GJFE-fed mice was notably increased compared to PBS-fed mice. This was due to an increase in thermogenic proteins in the inguinal white adipose tissue of the cold-exposed mice. Moreover, GJFE significantly increased thermogenic factors such as peroxisome proliferator-activated receptor gamma (PPARγ), uncoupling protein 1 (UCP1), and PPARγ coactivator 1 alpha (PGC1α) in vitro as well. Factors related to mitochondrial abundance and functions were also induced by GJFE in white and beige adipocytes. However, the treatment of PPARγ inhibitor abolished the GJFE-induced changes, indicating that activation of PPARγ is critical for the thermogenic effect of GJFE. In conclusion, GJFE induces thermogenic action by activating mitochondrial function via PPARγ activation. Through these findings, we suggest GJFE as a potential anti-obesity agent with a novel mechanism involving thermogenic action in white adipocytes.
Serum Vitamin D Is Associated with Antioxidant Potential in Peri-Parturient Cows
Authors: Strickland Jaimie M. , Wisnieski Lauren , Mavangira Vengai , Sordillo Lorraine M.
Published: September 2021

Dairy cows experience increased oxidative stress during periods of transition such as at the cessation of lactation and around the periparturient period, thus increasing disease risk. Despite routine supplementation of transition cow diets with certain vitamins in an attempt to mitigate oxidative stress, there is no currently available data directly linking vitamin supplementation with antioxidant potential (AOP) in transition cows. The objective of this study was to determine the association between serum vitamins and biomarkers of oxidative stress in healthy cows. Blood samples were collected from 240 cows at dry off (DO), close up (CU), and 2–10 days post-calving (DIM2-10). Blood samples were analyzed for vitamins (A, D, E), β-carotene, reactive oxygen species (ROS), and AOP. Spearman correlations and mixed linear regression models were used to assess associations between vitamins and measures of oxidant status. Vitamin D concentrations were positively associated with AOP at the CU and DIM2-10. Based on the positive association with AOP, additional in-vitro studies were conducted that showed vitamin D mitigated barrier integrity loss in endothelial cells during oxidative stress. These results indicate for the first time that vitamin D may have a role in promoting antioxidant potential in transition dairy cows.
Multiple-Input Convolutional Neural Network Model for Large-Scale Seismic Damage Assessment of Reinforced Concrete Frame Buildings
Authors: Xiong Chen , Zheng Jie , Xu Liangjin , Cen Chengyu , Zheng Ruihao , Li Yi
Published: September 2021

This study introduces a multiple-input convolutional neural network (MI-CNN) model for the seismic damage assessment of regional buildings. First, ground motion sequences together with building attribute data are adopted as inputs of the proposed MI-CNN model. Second, the prediction accuracy of MI-CNN model is discussed comprehensively for different scenarios. The overall prediction accuracy is 79.7%, and the prediction accuracies for all scenarios are above 77%, indicating a good prediction performance of the proposed method. The computation efficiency of the proposed method is 340 times faster than that of the nonlinear multi-degree-of-freedom shear model using time history analysis. Third, a case study is conducted for reinforced concrete (RC) frame buildings in Shenzhen city, and two seismic scenarios (i.e., M6.5 and M7.5) are studied for the area. The simulation results of the area indicate a good agreement between the MI-CNN model and the benchmark model. The outcomes of this study are expected to provide a useful reference for timely emergency response and disaster relief after earthquakes.
Grid-Scale Battery Energy Storage for Arbitrage Purposes: A Colombian Case
Authors: Peñaranda Andrés F. , Romero-Quete David , Cortés Camilo A.
Published: September 2021

This study seeks to determine a suitable arbitrage strategy that allows a battery energy storage system (BESS) owner to obtain the maximum economic benefits when participating in the Colombian electricity market. A comparison of different arbitration strategies from the literature, such as seasonal, statistical, and neural networks-based models, is performed. To determine BESS’s optimal operation, a Mixed Integer Linear Programming (MILP) optimization problem is formulated, including a battery degradation model based on an upper piecewise linear approximation method. A financial evaluation of the different arbitrage strategies is carried out, resulting, for all the analyzed cases, in a negative net present value (NPV); thus, the results show that the income obtained from BESS when only performing energy arbitrage in the Colombian market do not compensate the investment costs. Results have also shown that strategies based on statistical and prediction models have a better performance than seasonal strategies, especially in atypical circumstances such as COVID-19.
Enhancement of Polyphenols Recovery from Rosa canina, Calendula officinalis and Castanea sativa Using Pulsed Electric Field
Authors: Lakka Achillia , Bozinou Eleni , Stavropoulos Giorgos , Samanidis Iordanis , Athanasiadis Vassilis , Dourtoglou Vassilis G. , Makris Dimitris P. , Lalas Stavros I.
Published: September 2021

The current study evaluates the Pulsed Electric Field (PEF) technique for the extraction of polyphenols from the plants Rosa canina, Calendulaofficinalis and Castanea sativa. These plants are traditionally used both for the preparation of therapeutic decoctions and the aromatization of beverages (alcoholic or not). Pulses of 10 μs duration were used to apply electric field intensities ranging from 1.2 to 2.0 kV cm−1. The period of the phenomenon was set to 1 ms, with a total extraction time of 20 min. The total polyphenol content as well as the identified polyphenolic compounds of the extracts were determined for monitoring and evaluation. To estimate the PEF effect, control extracts were prepared using the same process as PEF extracts but without the application of electric field. For all the three plant materials studied, the PEF technique appeared to be successful in increasing polyphenols extraction. The application of a moderate to high electric field, up to 1.4 kV cm−1, resulted in increased total and individual polyphenols recovery, reaching 63.79% and 84%, respectively, in the case of Rosa canina fruits.
Intermittent Sequential Pneumatic Compression Improves Coupling between Cerebral Oxyhaemoglobin and Arterial Blood Pressure in Patients with Cerebral Infarction
Authors: Li Wenhao , Xu Gongcheng , Huo Congcong , Xie Hui , Lv Zeping , Zhao Haihong , Li Zengyong
Published: September 2021

This study aims to explore the effect of intermittent sequential pneumatic compression (ISPC) intervention on the coupling relationship between arterial blood pressure (ABP) and changes in oxyhaemoglobin (Δ [O2Hb]). The coupling strength between the two physiological systems was estimated using a coupling function based on dynamic Bayesian inference. The participants were 22 cerebral infarction patients and 20 age- and sex-matched healthy controls. Compared with resting state, the coupling strength from ABP to Δ [O2Hb] oscillations was significantly lower in the bilateral prefrontal cortex (PFC), sensorimotor cortex (SMC), and temporal lobe cortex (TLC) during the ISPC intervention in cerebral infarction patients in interval II. Additionally, the coupling strength was significantly lower in the bilateral SMC in both groups in interval III. These findings indicate that ISPC intervention may facilitate cerebral circulation in the bilateral PFC, SMC, and TLC in cerebral infarction patients. ISPC may promote motor function recovery through its positive influences on motor-related networks. Furthermore, the coupling between Δ [O2Hb] and ABP allows non-invasive assessments of autoregulatory function to quantitatively assess the effect of rehabilitation tasks and to guide therapy in clinical situations.
Carbonic Anhydrase IX and Survivin in Colorectal Adenocarcinoma Cells: Slovakian Population Study
Authors: Kováčová Zuzana , Hodorová Ingrid
Published: September 2021

The aim of this study was to detect carbonic anhydrase IX (CAIX) and survivin in the colorectal adenocarcinoma cells of the Slovakian population. We used an indirect three-step immunohistochemical method with DAB staining for the localization of the proteins and investigation their expression. We compared their expression with expression in healthy colorectal tissue. In 74 tissues of colorectal adenocarcinomas, 42% showed CAIX positivity and 20% showed survivin positivity. Brown membrane immunostaining was visible in CAIX-positive tumors. Survivin-positive tumors had strong brown cytoplasmic immunostaining. Co-expression of both proteins was present in five specimens (7%). The samples of normal colorectal tissue (without carcinoma) were CAIX-negative and survivin-negative. We also applied the Chi-squared test for evaluation statistically significant association between the expression of proteins and selected clinical and histopathological parameters. We did not find any statistically significant correlations between CAIX or survivin expression and sex of patients, the grade of the tumor, nodal status and presence of metastasis (p > 0.05). The fact that all samples of normal colorectal tissue were CAIX- and survivin-negative could lead to the possibility of using these two proteins as potential tumor diagnostic markers. On the basic of the available publications and data, we suggest that CAIX and survivin could be negative independent prognostic markers of colorectal cancer, which could affect response to therapy.
Second-Generation Neuroendocrine Immunohistochemical Markers: Reflections from Clinical Implementation
Authors: Juhlin Carl Christofer
Published: September 2021

When analyzing tumors by histopathology, endocrine pathologists have traditionally been restricted to a few key immunohistochemical markers related to secretory vesicles in order to pinpoint neuroendocrine differentiation—most notably Chromogranin A (CGA) and Synaptophysin (SYP). Although proven of great clinical utility, these markers sometimes exhibit tissue-specific patterns depending on tumor origin, and non-neuroendocrine tumors might sometimes display focal expression. Moreover, CGA and SYP might be partially or totally absent in highly proliferative neuroendocrine carcinomas, making the diagnosis particularly challenging on small biopsies of metastatic lesions with unknown location of the primary tumor. The advent of second-generation neuroendocrine markers ISL LIM Homeobox 1 (ISL1), INSM Transcriptional Repressor 1 (INSM1) and Secretagogin (SECG) have expanded the pathology toolbox considerably, constituting markers that often retain expression even in poorly differentiated neuroendocrine carcinomas. As non-neuroendocrine tumors seldom express these antigens, the specificity of ISL1, INSM1 and SECG make them welcome additions to clinical practice. In this commentary, recent advances of this field as well as initial clinical experiences from a tertiary neuroendocrine center are discussed.
Effect of Strain Rate on Single Tau, Dimerized Tau and Tau-Microtubule Interface: A Molecular Dynamics Simulation Study
Authors: Khan Md Ishak , Gilpin Kathleen , Hasan Fuad , Mahmud Khandakar Abu Hasan Al , Adnan Ashfaq
Published: September 2021

Microtubule-associated protein (MAP) tau is a cross-linking molecule that provides structural stability to axonal microtubules (MT). It is considered a potential biomarker for Alzheimer’s disease (AD), dementia, and other neurological disorders. It is also a signature protein for Traumatic Brain Injury (TBI) assessment. In the case of TBI, extreme dynamic mechanical energies can be felt by the axonal cytoskeletal members. As such, fundamental understandings of the responses of single tau protein, polymerized tau protein, and tau-microtubule interfaces under high-rate mechanical forces are important. This study attempts to determine the high-strain rate mechanical behavior of single tau, dimerized tau, and tau-MT interface using molecular dynamics (MD) simulation. The results show that a single tau protein is a highly stretchable soft polymer. During deformation, first, it significantly unfolds against van der Waals and electrostatic bonds. Then it stretches against strong covalent bonds. We found that tau acts as a viscoelastic material, and its stiffness increases with the strain rate. The unfolding stiffness can be ~50–500 MPa, while pure stretching stiffness can be >2 GPa. The dimerized tau model exhibits similar behavior under similar strain rates, and tau sliding from another tau is not observed until it is stretched to >7 times of original length, depending on the strain rate. The tau-MT interface simulations show that very high strain and strain rates are required to separate tau from MT suggesting Tau-MT bonding is stronger than MT subunit bonding between themselves. The dimerized tau-MT interface simulations suggest that tau-tau bonding is stronger than tau-MT bonding. In summary, this study focuses on the structural response of individual cytoskeletal components, namely microtubule (MT) and tau protein. Furthermore, we consider not only the individual response of a component, but also their interaction with each other (such as tau with tau or tau with MT). This study will eventually pave the way to build a bottom-up multiscale brain model and analyze TBI more comprehensively.
The Multiple Roles of Sphingomyelin in Parkinson’s Disease
Authors: Signorelli Paola , Conte Carmela , Albi Elisabetta
Published: September 2021

Advances over the past decade have improved our understanding of the role of sphingolipid in the onset and progression of Parkinson’s disease. Much attention has been paid to ceramide derived molecules, especially glucocerebroside, and little on sphingomyelin, a critical molecule for brain physiopathology. Sphingomyelin has been proposed to be involved in PD due to its presence in the myelin sheath and for its role in nerve impulse transmission, in presynaptic plasticity, and in neurotransmitter receptor localization. The analysis of sphingomyelin-metabolizing enzymes, the development of specific inhibitors, and advanced mass spectrometry have all provided insight into the signaling mechanisms of sphingomyelin and its implications in Parkinson’s disease. This review describes in vitro and in vivo studies with often conflicting results. We focus on the synthesis and degradation enzymes of sphingomyelin, highlighting the genetic risks and the molecular alterations associated with Parkinson’s disease.
Combination of Stem Cells and Rehabilitation Therapies for Ischemic Stroke
Authors: Berlet Reed , Anthony Stefan , Brooks Beverly , Wang Zhen-Jie , Sadanandan Nadia , Shear Alex , Cozene Blaise , Gonzales-Portillo Bella , Parsons Blake , Salazar Felipe Esparza , Lezama Toledo Alma R. , Monroy Germán Rivera , Gonzales-Portillo Joaquín Vega , Borlongan Cesario V.
Published: September 2021

Stem cell transplantation with rehabilitation therapy presents an effective stroke treatment. Here, we discuss current breakthroughs in stem cell research along with rehabilitation strategies that may have a synergistic outcome when combined together after stroke. Indeed, stem cell transplantation offers a promising new approach and may add to current rehabilitation therapies. By reviewing the pathophysiology of stroke and the mechanisms by which stem cells and rehabilitation attenuate this inflammatory process, we hypothesize that a combined therapy will provide better functional outcomes for patients. Using current preclinical data, we explore the prominent types of stem cells, the existing theories for stem cell repair, rehabilitation treatments inside the brain, rehabilitation modalities outside the brain, and evidence pertaining to the benefits of combined therapy. In this review article, we assess the advantages and disadvantages of using stem cell transplantation with rehabilitation to mitigate the devastating effects of stroke.
Carbon Nanofibers versus Silver Nanoparticles: Time-Dependent Cytotoxicity, Proliferation, and Gene Expression
Authors: Salesa Beatriz , Assis Marcelo , Andrés Juan , Serrano-Aroca Ángel
Published: September 2021

Carbon nanofibers (CNFs) are one-dimensional nanomaterials with excellent physical and broad-spectrum antimicrobial properties characterized by a low risk of antimicrobial resistance. Silver nanoparticles (AgNPs) are antimicrobial metallic nanomaterials already used in a broad range of industrial applications. In the present study these two nanomaterials were characterized by Raman spectroscopy, transmission electron microscopy, zeta potential, and dynamic light scattering, and their biological properties were compared in terms of cytotoxicity, proliferation, and gene expression in human keratinocyte HaCaT cells. The results showed that both AgNPs and CNFs present similar time-dependent cytotoxicity (EC50 of 608.1 µg/mL for CNFs and 581.9 µg/mL for AgNPs at 24 h) and similar proliferative HaCaT cell activity. However, both nanomaterials showed very different results in the expression of thirteen genes (superoxide dismutase 1 (SOD1), catalase (CAT), matrix metallopeptidase 1 (MMP1), transforming growth factor beta 1 (TGFB1), glutathione peroxidase 1 (GPX1), fibronectin 1 (FN1), hyaluronan synthase 2 (HAS2), laminin subunit beta 1 (LAMB1), lumican (LUM), cadherin 1 CDH1, collagen type IV alpha (COL4A1), fibrillin (FBN), and versican (VCAN)) treated with the lowest non-cytotoxic concentrations in the HaCaT cells after 24 h. The AgNPs were capable of up-regulating only two genes (SOD1 and MMP1) while the CNFs were very effective in up-regulating eight genes (FN1, MMP1, CAT, CDH1, COL4A1, FBN, GPX1, and TGFB1) involved in the defense mechanisms against oxidative stress and maintaining and repairing tissues by regulating cell adhesion, migration, proliferation, differentiation, growth, morphogenesis, and tissue development. These results demonstrate CNF nanomaterials’ unique great potential in biomedical applications such as tissue engineering and wound healing.
Novel Mutations Detection with Next-Generation Sequencing and Its Association with Clinical Outcome in Unilateral Primary Aldosteronism
Authors: Wu Che-Hsiung , Peng Kang-Yung , Hwang Daw-Yang , Lin Yen-Hung , Wu Vin-Cent , Chueh Jeff S.
Published: September 2021

Somatic mutations have been identified in adrenal tissues of unilateral primary aldosteronism (uPA). The spectrum of somatic mutations in uPAs was investigated using a customized and targeted next-generation sequencing (cNGS) approach. We also assessed whether cNGS or Sanger sequencing-identified mutations have an association with clinical outcomes in uPA. Adrenal tumoral tissues of uPA patients who underwent adrenalectomy were obtained. Conventional somatic mutation hotspots in 240 extracted DNA samples were initially screened using Sanger sequencing. A total of 75 Sanger-negative samples were further investigated by sequencing the entire coding regions of the known aldosterone-driver genes by our cNGS gene panel. Somatic mutations in aldosterone-driver genes were detected in 21 (28%) of these samples (8.8% of all samples), with 9 samples, including mutations in CACNA1D gene (12%), 5 in CACNA1H (6.6%), 3 in ATP2B3 (4%), 2 in CLCN2 (2.6%), 1 in ATP1A1 (1.3%), and 1 in CTNNB1 (1.3%). Via combined cNGS and Sanger sequencing aldosterone-driver gene mutations were detected in altogether 186 of our 240 (77.5%) uPA samples. The complete clinical success rate of patients containing cNGS-identified mutations was higher than those without mutations (odds ratio (OR) = 10.9; p = 0.012). Identification of somatic mutations with cNGS or Sanger sequencing may facilitate the prediction of complete clinical success after adrenalectomy in uPA patients.
Recent Advances in Exosome-Based Drug Delivery for Cancer Therapy
Authors: Kim Hyosuk , Jang Hochung , Cho Haeun , Choi Jiwon , Hwang Kwang Yeon , Choi Yeonho , Kim Sun Hwa , Yang Yoosoo
Published: September 2021

Exosomes are a class of extracellular vesicles, with a size of about 100 nm, secreted by most cells and carrying various bioactive molecules such as nucleic acids, proteins, and lipids, and reflect the biological status of parent cells. Exosomes have natural advantages such as high biocompatibility and low immunogenicity for efficient delivery of therapeutic agents such as chemotherapeutic drugs, nucleic acids, and proteins. In this review, we introduce the latest explorations of exosome-based drug delivery systems for cancer therapy, with particular focus on the targeted delivery of various types of cargoes.
Single Nanowire Gas Sensor Able to Distinguish Fish and Meat and Evaluate Their Degree of Freshness
Authors: Tonezzer Matteo
Published: September 2021

A non-invasive, small, and fast device is needed for food freshness monitoring, as current techniques do not meet these criteria. In this study, a resistive sensor composed of a single semiconductor nanowire was used at different temperatures, combining the responses and processing them with multivariate statistical analysis techniques. The sensor, very sensitive to ammonia and total volatile basic nitrogen, proved to be able to distinguish samples of fish (marble trout, Salmo trutta marmoratus) and meat (pork, Sus scrofa domesticus), both stored at room temperature and 4 °C in the refrigerator. Once separated, the fish and meat samples were classified by the degree of freshness/degradation with two different classifiers. The sensor classified the samples (trout and pork) correctly in 95.2% of cases. The degree of freshness was correctly assessed in 90.5% of cases. Considering only the errors with repercussions (when a fresh sample was evaluated as degraded, or a degraded sample was evaluated as edible) the accuracy increased to 95.2%. Considering the size (less than a square millimeter) and the speed (less than a minute), this type of sensor could be used to monitor food production and distribution chains.
Clinical Characteristics and Underlying Factors Related to Recovery from Severe Pneumonia in Under-Five Children with or without Malnutrition Treated at Health Care Facilities in Bangladesh
Authors: Huq K. A. T. M. Ehsanul , Moriyama Michiko , Matsuyama Ryota , Chisti Mohammod Jobayer , Rahman Md Moshiur , Alam Nur Haque
Published: September 2021

Severe pneumonia with co-morbidity of malnutrition is one of the leading causes of death among children younger than five years of age. We aimed to compare the clinical features related to recovery from severe pneumonia in malnourished and well-nourished under-five children. A significantly lesser proportion of malnourished children compared to well-nourished recovered from rapid breathing (86.5% vs. 90.2%; p = 0.035), chest wall in-drawing (90.5% vs. 93.9%; p = 0.019), and fever (92.2% vs. 95.2%; p = 0.021) on day six after admission to health-care facilities. Malnourished children with severe pneumonia had significantly more rapid breathing (Adjusted Odds Ratio (AOR)) 1.636, 95% Confidence interval (CI) 1.150–2.328 p = 0.006), chest wall in-drawing (AOR 1.698, 95% CI 1.113–2.590, p = 0.014), and fever (AOR 1.700, 95% CI 1.066–2.710, p = 0.026) compared to those in well-nourished children. The study results suggested the lesser disappearance of clinical features among the malnourished children in Bangladesh underscores their vulnerability to severe pneumonia.
COVID-19 and Inherited Metabolic Disorders: One-Year Experience of a Referral Center
Authors: Tummolo Albina , Paterno Giulia , Dicintio Annamaria , Stefanizzi Pasquale , Melpignano Livio , Aricò Maurizio
Published: September 2021

Understanding the potential risks of patients with inherited metabolic disorder (IMD) exposed to the COVID-19 pandemic is an unmet need for those involved in their management. Here, we report on the incidence of COVID-19 in a cohort of patients with IMD treated at a children’s hospital and compare them with a matched control group. Among the total number of 272 patients actively followed at a referral center, 19 (7%) tested positive for SARS-CoV-2 between March 2020 and March 2021. Their median age was 16.2 years (range 1.4–32.8 years). In two-thirds of the cases, the source of infection was a family member; 12/19 patients (63%) were asymptomatic, only one required hospitalization, and none of them died. In our single-center experience, COVID-19 had a moderate impact on a relatively large cohort of patients with IMD, including children and young adults. The clinical course was very mild in all but one case. The proportion of symptomatic cases and the clinical course were comparable in patients with IMD and in a group of matched, non-IMD COVID-19 controls from the general population.
Corrosion Behavior of NiTi Alloys Fabricate by Selective Laser Melting Subjected to Femtosecond Laser Shock Peening
Authors: Ma Long , Li Wanqing , Yang Yongzhi , Ma Yuanxue , Luo Kai , Jia Bochao , Xu Zezhou , Yu Zhenglei
Published: September 2021

NiTi alloys are commonly used in many fields such as aerospace, mechanical engineering due to their excellent mechanical properties and shape memory effect. In recent years, the emergence of selective laser melting (SLM) technology provides a new method for the preparation of NiTi parts. But the surface corrosion failure of SLM-NiTi is the most common problem. This paper mainly focuses on the research of femtosecond laser shock peening of the surface of SLM-NiTi alloy to improve the corrosion resistance. Selecting different scanning space (1 μm, 3 μm, 5 μm, 10 μm), and analyze the surface morphology of the material through the OM, SEM, EDS and white light interferometer, and investigate the surface nanohardness and corrosion resistance through nanoindentation and electrochemical testing. The research results show that part of the TiO2 is formed under different scanning spaces, and part of NiO is formed when the scanning space is 1μm. At the same time, it is found that the sample under the condition of 10 μm has the most excellent corrosion resistance and nanohardness. The nanohardness reaches 1303 ± 40 HV and the corrosion current density reaches 1.45 ± 0.1 × 10−9 A·cm−2. Proper femtosecond laser treatment can effectively improve the surface strength and corrosion resistance of the NiTi alloys.
Performance of the Boost Converter Controlled with ZAD to Regulate DC Signals
Authors: Trujillo Simeón Casanova , Candelo-Becerra John E. , Hoyos Fredy E.
Published: September 2021

This paper presents the performance of a boost converter controlled with a zero average dynamics technique to regulate direct current signals. The boost converter is modeled in a compact form, and a variable change is performed to depend only on the γ parameter. A new sliding surface is proposed, where it is possible to regulate both the voltage and the current with low relative errors with respect to the reference signals. It is analytically demonstrated that the approximation of the switching surface by a piecewise linear technique is efficient in controlling the system. It is shown numerically that for certain operating conditions, the system is evolved into a chaotic attractor. The zero average dynamics technique implemented in the boost converter has good regulation, due to the presence of zones in the bi-parametric space. Furthermore, the zero average dynamics technique regulates the voltage well and presents a chaotic attractor with low steady-state error.
Plaintext-Related Dynamic Key Chaotic Image Encryption Algorithm
Authors: Wu Zeming , Pan Ping , Sun Chunyang , Zhao Bing
Published: September 2021

To address the problems of the high complexity and low security of the existing image encryption algorithms, this paper proposes a dynamic key chaotic image encryption algorithm with low complexity and high security associated with plaintext. Firstly, the RGB components of the color image are read, and the RGB components are normalized to obtain the key that is closely related to the plaintext, and then the Arnold transform is used to stretch and fold the RGB components of the color image to change the position of the pixel points in space, so as to destroy the correlation between the adjacent pixel points of the image. Next, the generated sequences are independently encrypted with the Arnold-transformed RGB matrix. Finally, the three encrypted images are combined to obtain the final encrypted image. Since the key acquisition of this encryption algorithm is related to the plaintext, it is possible to achieve one key per image, so the key acquisition is dynamic. This encryption algorithm introduces chaotic mapping, so that the key space size is 10180. The key acquisition is closely related to the plaintext, which makes the ciphertext more random and resistant to differential attacks, and ensures that the ciphertext is more secure after encryption. The experiments show that the algorithm can encrypt the image effectively and can resist attack on the encrypted image.
Moodle Quizzes as a Continuous Assessment in Higher Education: An Exploratory Approach in Physical Chemistry
Authors: López-Tocón Isabel
Published: September 2021

The use of Moodle quizzes as a continuous assessment and an integral part of the educational methodology in higher education has been analyzed in a case study of physical chemistry subject. Two types of quiz designed with different item types and different settings, called basic quiz (BQ) and thematic block quiz (TBQ), were elaborated making use of a question bank with more than 450 items. BQ has true/false items, while TBQ has randomly mixed items (multiple choice, numerical and matching). The effect of the type of quiz on the student scores is analyzed according to statistical and psychometric data such as the degree of participation, the facility index and the discrimination index of each item, and the average score, calculated according to the classical test theory. This allows us to discern which type of quiz has an enough quality to use it as an assessment tool. Moreover, the effect of this educational activity, developed during the last six academic years from 2014 to 2020, just before of the pandemic situation, is evaluated considering the scores of the students in the Ordinary Calls of exams and comparing them with previous courses taught with a traditional education based on master classes. The statistic results indicate that TBQs are more discriminative than BQs and could be used as an assessment tool, while BQs could be only useful as formative activity. Moodle quizzes turn out to be a reliable strategy for learning of contents in scientific matter, with a high participation in the knowledge tests, with good marks in the average score and a greater number of pass degrees in the Ordinary Calls.
Exploring the Relationship between Saber Pro Test Outcomes and Student Teacher Characteristics in Colombia: Recommendations for Improving Bachelor’s Degree Education
Authors: Sáenz-Castro Paola , Vlachopoulos Dimitrios , Fàbregues Sergi
Published: September 2021

This explanatory sequential mixed methods study explores the perceptions of academic and administrative managers responsible for teacher training at a public university in Colombia, as well as their views on improving such training after learning about the performance of teachers student teachers in the 2019 Saber Pro test, the differences in their test scores, and the relationships and statistical correlations between these outcomes and the students’ personal, family, socioeconomic and academic characteristics. Our findings show significant differences in the student teachers’ mean scores and performance when data are grouped according to personal, socioeconomic and academic conditions; a significant relationship between performance and student teacher characteristics; and correlations between critical reading scores and the other competencies assessed. Our data also highlight the lack of knowledge among academic and administrative managers about students’ life circumstances and the diversity of factors that may impact their performance; the importance of correlational data; the difference between expected and true outcomes; the inequity under which students seem to pursue their education; the limitations in access to resources; the training required for teachers to be able to analyze quantitative data and use specific software; the impact of teachers’ critical reading skills on student outcomes; the importance of data-driven decision-making; and the need for teachers to engage in quantitative research practices.
The Importance of First Semester Seminars for At-Risk First-Year Students: Analysis of Student Skills and Time Spent on Class Preparation
Authors: Reed David E. , Jones Guinevere Z.
Published: September 2021

The high-school-to-college transition can be difficult as students are adapting to a multitude of academic and social changes simultaneously. The University of Wyoming has created a first-semester program targeted at development of student skills for at-risk students using paired first-year seminar classes. Using student survey data from both pre- and post-course series, students were asked how important they thought academic and non-academic skills were as well as how much preparation time they were spending outside of class. Results from this work show large changes in the importance of skills and time spent studying during the transition from high school to college. This highlights the need to focus specifically on teaching skills to help students through the transition and suggests that not all skills are equal and data shows that students take longer than one semester to match their expected and actual amounts of time they spend outside of class studying.
Analyzing Socially Shared Regulation of Learning during Cooperative Learning and the Role of Equal Contribution: A Grounded Theory Approach
Authors: Hogenkamp Loes , van Dijk Alieke M. , Eysink Tessa H. S.
Published: September 2021

Although cooperative learning is an effective instructional method, it cannot be taken for granted that students will gain new knowledge when engaging in a cooperative activity. Even if cooperative learning is effectively designed, problems might arise regarding cognitive, behavioral and motivational aspects of learning. For students to gain knowledge, cognition, metacognition, behavior and motivation should be collectively regulated by the group, which is called the socially shared regulation of learning (SSRL). However, up until now, there has been no consensus about how SSRL is manifested during cooperative learning. This study investigated how SSRL is manifested during cooperative learning by means of a grounded theory approach. This was done to identify what is necessary for effective SSRL and what its consequences are. A theoretical model was built based on the data in order to portray these prerequisites and consequences of SSRL. This study also investigated whether equal participation fostered SSRL. In this study, participants were students from the fourth, fifth and sixth grades of elementary school, working together in groups of four (n = 104). The data indicated that SSRL is a rare process, the absence of which caused less structured collaboration in groups who were not prompted to participate equally.
Discrete Pseudo-Fractional Fourier Transform and Its Fast Algorithm
Authors: Majorkowska-Mech Dorota , Cariow Aleksandr
Published: September 2021

In this article, we introduce a new discrete fractional transform for data sequences whose size is a composite number. The main kernels of the introduced transform are small-size discrete fractional Fourier transforms. Since the introduced transformation is not, in the generally known sense, a classical discrete fractional transform, we call it discrete pseudo-fractional Fourier transform. We also provide a generalization of this new transform, which depends on many fractional parameters. A fast algorithm for computing the introduced transform is developed and described.
Fault-Tolerant FPGA-Based Nanosatellite Balancing High-Performance and Safety for Cryptography Application
Authors: Gantel Laurent , Berthet Quentin , Amri Emna , Karlov Alexandre , Upegui Andres
Published: September 2021

With the growth of the nano-satellites market, the usage of commercial off-the-shelf FPGAs for payload applications is also increasing. Due to the fact that these commercial devices are not radiation-tolerant, it is necessary to enhance them with fault mitigation mechanisms against Single Event Upsets (SEU). Several mechanisms such as memory scrubbing, triple modular redundancy (TMR) and Dynamic and Partial Reconfiguration (DPR), can help to detect, isolate and recover from SEU faults. In this paper, we introduce a dynamically reconfigurable platform equipped with configuration memory scrubbing and TMR mechanisms. We study their impacts when combined with DPR, providing three different execution modes: low-power, safe and high-performance mode. The fault detection mechanism permits the system to measure the radiation level and to estimate the risk of future faults. This enables the possibility of dynamically selecting the appropriate execution mode in order to adopt the best trade-off between performance and reliability. The relevance of the platform is demonstrated in a nano-satellite cryptographic application running on a Zynq UltraScale+ MPSoC device. A fault injection campaign has been performed to evaluate the impact of faulty configuration bits and to assess the efficiency of the proposed mitigation and the overall system reliability.
Optimized Polar Codes as Forward Error Correction Coding for Digital Video Broadcasting Systems
Authors: El-Abbasy Karim , Taki Eldin Ramy , El Ramly Salwa , Abdelhamid Bassant
Published: September 2021

Polar codes are featured by their low encoding/decoding complexity for symmetric binary input-discrete memoryless channels. Recently, flexible generic Successive Cancellation List (SCL) decoders for polar codes were proposed to provide different throughput, latency, and decoding performances. In this paper, we propose to use polar codes with flexible fast-adaptive SCL decoders in Digital Video Broadcasting (DVB) systems to meet the growing demand for more bitrates. In addition, they can provide more interactive services with less latency and more throughput. First, we start with the construction of polar codes and propose a new mathematical relation to get the optimized design point for the polar code. We prove that our optimized design point is too close to the one that achieves minimum Bit Error Rate (BER). Then, we compare the performance of polar and Low-Density Parity Check (LDPC) codes in terms of BER, encoder/decoder latencies, and throughput. The results show that both channel coding techniques have comparable BER. However, polar codes are superior to LDPC in terms of decoding latency, and system throughput. Finally, we present the possible performance enhancement of DVB systems in terms of decoding latency and complexity when using optimized polar codes as a Forward Error Correction (FEC) technique instead of Bose Chaudhuri Hocquenghem (BCH) and LDPC codes that are currently adopted in DVB standards.
Co-Simulation Analysis for Performance Prediction of Synchronous Reluctance Drives
Authors: Varvolik Vasyl , Prystupa Dmytro , Buticchi Giampaolo , Peresada Sergei , Galea Michael , Bozhko Serhiy
Published: September 2021

To improve the design of electric drives and to better predict the system performance, numerical simulation has been widely employed. Whereas in the majority of the approaches, the machines and the power electronics are designed and simulated separately, to improve the fidelity, a co-simulation should be performed. This paper presents a complete coupled co-simulation model of synchronous reluctance machine (SynRel) drive, which includes the finite element model of the SynRel, the power electronics inverter, the control system, and application examples. The model of SynRel is based on a finite element model (FEM) using Simcenter MagNet. The power electronics inverter is built using PLECS Blockset, and the drive control model is built in Simulink environment, which allows for coupling between MagNet and PLECS. The proposed simulation model provides high accuracy thanks to the complete FEA-based model fed by actual inverter voltage. The comparison of the simulation results with experimental measurements shows good correspondence.
Accurate Realtime Motion Estimation Using Optical Flow on an Embedded System
Authors: Ammar Anis , Fredj Hana Ben , Souani Chokri
Published: September 2021

Motion estimation has become one of the most important techniques used in realtime computer vision application. There are several algorithms to estimate object motions. One of the most widespread techniques consists of calculating the apparent velocity field observed between two successive images of the same scene, known as the optical flow. However, the high accuracy of dense optical flow estimation is costly in run time. In this context, we designed an accurate motion estimation system based on the calculation of the optical flow of a moving object using the Lucas–Kanade algorithm. Our approach was applied on a local treatment region implemented into Raspberry Pi 4, with several improvements. The efficiency of our accurate realtime implementation was demonstrated by the experimental results, showing better performance than with the conventional calculation.
Ultra-Wideband Reconfigurable X-Band and Ku-Band Metasurface Beam-Steerable Reflector for Satellite Communications
Authors: Rotshild David , Abramovich Amir
Published: September 2021

A continuously reconfigurable metasurface reflector based on unit cell mushroom geometry that was integrated with a varactor diode is presented in this paper. The unit cell of the metasurface was designed and optimized to operate in the X-band and Ku-band, improving satellite communication’s quality of service. The losses mechanisms of continuous control over the unit cell phase reflection in beam steering resolution are considered and the analysis results are presented. The unit cell design parameters were analyzed with an emphasis on losses and dynamic reflection phase range. The unit cell magnitude and phase reflection are shown in the wide frequency bandwidth and showed a good agreement between all the measurements and the simulations. This metasurface enabled a high dynamic range in the unit cell resonant frequency range from 7.8 to 15 GHz. In addition, the reflection phase and absorption calibration are demonstrated for multiple operating frequencies, namely, 11 GHz, 12 GHz, and 13.5 GHz. Furthermore, design trade-offs and manufacturing limitations were considered. Finally, a beam-steering simulation using the designed metasurface is shown and discussed.
Breaking KASLR Using Memory Deduplication in Virtualized Environments
Authors: Kim Taehun , Kim Taehyun , Shin Youngjoo
Published: September 2021

Recent operating systems (OSs) have adopted a defense mechanism called kernel page table isolation (KPTI) for protecting the kernel from all attacks that break the kernel address space layout randomization (KASLR) using various side-channel analysis techniques. In this paper, we demonstrate that KASLR can still be broken, even with the latest OSs where KPTI is applied. In particular, we present a novel memory-sharing-based side-channel attack that breaks the KASLR on KPTI-enabled Linux virtual machines. The proposed attack leverages the memory deduplication feature on a hypervisor, which provides a timing channel for inferring secret information regarding the victim. By conducting experiments on KVM and VMware ESXi, we show that the proposed attack can obtain the kernel address within a short amount of time. We also present several countermeasures that can prevent such an attack.