bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehensive Phytochemical Analysis and Bioactivity Evaluation of Padina boergesenii: Unveiling Its Prospects as a Promising Cosmetic Component
Authors: Kalasariya Haresh S. , Pereira Leonel , Patel Nikunj B.
Published: June 2023

Marine macroalgae, such as Padina boergesenii, are gaining recognition in the cosmetics industry as valuable sources of natural bioactive compounds. This study aimed to investigate the biochemical profile of P. boergesenii and evaluate its potential as a cosmetic ingredient. Fourier-transform infrared (FTIR), gas chromatography–mass spectrometry (GCMS), and high-resolution liquid chromatography–mass spectrometry quadrupole time-of-flight (HRLCMS QTOF) analyses were employed to assess the functional groups, phycocompounds, and beneficial compounds present in P. boergesenii. Pigment estimation, total phenol and protein content determination, DPPH antioxidant analysis, and tyrosinase inhibition assay were conducted to evaluate the extracts’ ability to counteract oxidative stress and address hyperpigmentation concerns. Elemental composition and amino acid quantification were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES) and HRLCMS, respectively. FTIR spectroscopy confirmed diverse functional groups, including halo compounds, alcohols, esters, amines, and acids. GCMS analysis identified moisturizing, conditioning, and anti-aging compounds such as long-chain fatty alcohols, fatty esters, fatty acids, and hydrocarbon derivatives. HRLCMS QTOF analysis revealed phenolic compounds, fatty acid derivatives, peptides, terpenoids, and amino acids with antioxidant, anti-inflammatory, and skin-nourishing properties. Elemental analysis indicated varying concentrations of elements, with silicon (Si) being the most abundant and copper (Cu) being the least abundant. The total phenol content was 86.50 µg/mL, suggesting the presence of antioxidants. The total protein content was 113.72 µg/mL, indicating nourishing and rejuvenating effects. The ethanolic extract exhibited an IC50 value of 36.75 μg/mL in the DPPH assay, indicating significant antioxidant activity. The methanolic extract showed an IC50 value of 42.784 μg/mL. Furthermore, P. boergesenii extracts demonstrated 62.14% inhibition of tyrosinase activity. This comprehensive analysis underscores the potential of P. boergesenii as an effective cosmetic ingredient for enhancing skin health. Given the increasing use of seaweed-based bioactive components in cosmetics, further exploration of P. boergesenii’s potential in the cosmetics industry is warranted to leverage its valuable properties.
Peptidomics Analysis Reveals the Buccal Gland of Jawless Vertebrate Lamprey as a Source of Multiple Bioactive Peptides
Authors: Wang Yaocen , Sun Feng , Wang Zhuoying , Duan Xuyuan , Li Qingwei , Pang Yue , Gou Meng
Published: June 2023

Various proteins with antibacterial, anticoagulant, and anti-inflammatory properties have been identified in the buccal glands of jawless blood-sucking vertebrate lampreys. However, studies on endogenous peptides in the buccal gland of lampreys are limited. In this study, 4528 endogenous peptides were identified from 1224 precursor proteins using peptidomics and screened for bioactivity in the buccal glands of the lamprey, Lethenteron camtschaticum. We synthesized four candidate bioactive peptides (VSLNLPYSVVRGEQFVVQA, DIPVPEVPILE, VVQLPPVVLGTFG, and VPPPPLVLPPASVK), calculated their secondary structures, and validated their bioactivity. The results showed that the peptide VSLNLPYSVVRGEQFVVQA possessed anti-inflammatory activity, which significantly increased the expression of anti-inflammatory factors and decreased the expression of inflammatory factors in THP-1 cells. The peptide VVQLPPVVLGTFG showed antibacterial activity against some gram-positive bacteria. The peptide VSLNLPYSVVRGEQFVQA possessed good ACE inhibitory activity at low concentrations, but no dose-related correlation was observed. Our study revealed that the buccal glands of the jawless vertebrate lamprey are a source of multiple bioactive peptides, which will provide new insights into the blood-sucking mechanism of lamprey.
Synthesis of Cystine-Stabilised Dicarba Conotoxin EpI: Ring-Closing Metathesis of Sidechain Deprotected, Sulfide-Rich Sequences
Authors: Thomson Amy L. , Robinson Andrea J. , Belgi Alessia
Published: June 2023

Recombinant peptide synthesis allows for large-scale production of peptides with therapeutic potential. However, access to dicarba peptidomimetics via sidechain-deprotected sequences becomes challenging with exposed Lewis basicity presented by amine and sulfur-containing residues. Presented here is a combination of strategies which can be used to deactivate coordinative residues and achieve high-yielding Ru-catalyzed ring-closing metathesis. The chemistry is exemplified using α-conotoxin EpI, a native bicyclic disulfide-containing sequence isolated from the marine conesnail Conus episcopatus. Replacement of the loop I disulfide with E/Z–dicarba bridges was achieved with high conversion via solution-phase ring-closing metathesis of the unprotected linear peptide after simple chemoselective oxidation and ion-exchange masking of problematic functionality. Metathesis was also attempted in green solvent choices to further improve the sustainability of dicarba peptide synthesis.
Cervical Cancer and Human Papillomavirus Awareness among Women in Antigua and Barbuda
Authors: Honnavar Prasanna , Mansoor Edmond , Tulloch Cherie , Udayan Uttam , Cosmello Isabella , Patel Purva , Bersma Ashley
Published: June 2023

Background and objectives: Cervical cancer is the fourth leading cause of cancer-related deaths in women. Human papilloma virus (HPV) is known to cause cervical cancer. The incidence and mortality of cervical cancer has drastically reduced due to effective vaccination against HPV in developed countries. The projected rise in cervical cancer cases in Latin American and Caribbean countries necessitates a study to evaluate awareness about HPV, cervical cancer, the HPV vaccine, and prevention among women in Antigua and Barbuda. Materials and methods: This was an observational, cross-sectional study. The participants were women aged between 18 and 65 years, residing in Antigua and Barbuda. The study was conducted over the period of February to April 2023. After taking informed consent electronically, sociodemographic and behavioral data was collected through questionnaires sent out as links and QR-codes and were analyzed by QualtricsXM. The association between the demographic groups and awareness about HPV, cervical cancer, the HPV vaccine, and prevention was analyzed by a Chi-square test. Results: In total, 467 women were included in the study. The percentage of participants aware of HPV was 91.6% (n = 412). A total of 70.7% (n = 318) and 56.7% (n = 255) women were aware that cervical cancer is caused by HPV and is sexually transmitted, respectively. Although 70.6% (n = 315) of participants were aware that the vaccine protects against HPV, only 12.8% (n = 57) were vaccinated. Of the participants, 49.7% (n = 192) were willing to get vaccinated. The percentage of participants aware of the Papanicolaou (Pap) smear procedure was 98.9% (n = 435) and 87.8% (n = 382) had a Pap smear within the last 10 years while 12.2% (n = 53) never had a Pap smear screening. The willingness to know more information about HPV and the HPV vaccine among the participants was 77% (n = 335). Conclusions: The overall awareness among women in Antigua and Barbuda about HPV, cervical cancer, the HPV vaccine, and prevention was high. We recommend a national health education program and vaccine drive to complement our findings.
Antimicrobial Prescribing Preparedness of Croatian Medical Students—Did It Change between 2015 and 2019?
Authors: Palčevski Dora , Belančić Andrej , Mikuličić Ivan , Oštarijaš Eduard , Likić Robert , Dyar Oliver , Vlahović-Palčevski Vera
Published: June 2023

Background: Antimicrobials are some of the most prescribed drugs by junior doctors, but studies suggest most medical graduates feel unprepared for their future prescribing tasks. The aim of the present study was to compare the self-reported preparedness to prudently prescribe antimicrobials of final-year medical students in Croatia in 2015 and 2019. Methods: The same self-reported web-based survey on the preparedness to prescribe antibiotics was used in both 2015 and 2019. All final-year students at all four medical schools in Croatia (Osijek, Rijeka, Split, and Zagreb) were invited to participate in both 2015 and 2019. Preparedness scores were divided into “topic preparedness scores” and “global preparedness scores”. Topic preparedness scores represented the percentage of students at a medical school who felt sufficiently prepared for each topic. They were first established at a medical school level and then at the national level. Global preparedness scores were determined for each student separately and then calculated at the medical school and national levels. Results: The country’s global preparedness score, representing the average proportion of topics in which students felt sufficiently prepared, was slightly higher in 2015 compared with the 2019 results (62.7% vs. 56.5%; p = 0.191). Croatian students reported higher preparedness in 2015 than in 2019 for 25 out of 27 topics included in the survey. The majority of students reported a need for more education on antibiotic use both in 2015 and 2019 (78.0% vs. 83.0%; p = 0.199). Conclusions: Despite increasing antimicrobial stewardship activities in various healthcare settings, medical students who are about to start prescribing antibiotics on their own do not feel sufficiently prepared to do so. Antimicrobial stewardship programs should be designed to incorporate undergraduate medical student education, for instance, as a specific, mandatory course or integrated into other courses, such as clinical pharmacology.
Building Asymmetric Lipid Bilayers for Molecular Dynamics Simulations: What Methods Exist and How to Choose One?
Authors: Chaisson Emily H. , Heberle Frederick A. , Doktorova Milka
Published: June 2023

The compositional asymmetry of biological membranes has attracted significant attention over the last decade. Harboring more differences from symmetric membranes than previously appreciated, asymmetric bilayers have proven quite challenging to study with familiar concepts and techniques, leaving many unanswered questions about the reach of the asymmetry effects. One particular area of active research is the computational investigation of composition- and number-asymmetric lipid bilayers with molecular dynamics (MD) simulations. Offering a high level of detail into the organization and properties of the simulated systems, MD has emerged as an indispensable tool in the study of membrane asymmetry. However, the realization that results depend heavily on the protocol used for constructing the asymmetric bilayer models has sparked an ongoing debate about how to choose the most appropriate approach. Here we discuss the underlying source of the discrepant results and review the existing methods for creating asymmetric bilayers for MD simulations. Considering the available data, we argue that each method is well suited for specific applications and hence there is no single best approach. Instead, the choice of a construction protocol—and consequently, its perceived accuracy—must be based primarily on the scientific question that the simulations are designed to address.
Rosacea Meibomian Gland Dysfunction Posterior Blepharitis May Be a Marker for Earlier Associated Dyslipidaemia and Inflammation Detection and Treatment with Statins
Authors: Ooi Kenneth G. , Watson Stephanie L.
Published: June 2023

Posterior blepharitis and dry eye are common disorders with meibomian gland dysfunction (MGD), a principal driver of their pathophysiology. Meibomian gland dysfunction is increasingly prevalent in older populations with contributory hormonal imbalances. The abnormal meibum in MGD has been documented to have an excess of cholesterol with a resultant disruption of the lipid layer of the tear film. This leads to tear film instability due to the inadequate trapping of the aqueous portion of the tear film with resultant evaporative dry eye. Significant morbidity may follow MGD with ocular surface inflammation disrupting both social and work function. Rosacea is a common chronic inflammatory condition of the central face but can have ocular and systemic inflammatory associations. It is especially prevalent in North European populations and can have onset at any age, but commonly presents between thirty and fifty years of age. In ocular rosacea, MGD is a recognised manifestation as is dyslipidaemia. Ocular rosacea can predate cutaneous disease. As yet, there is no directly reported evidence of the efficacy of the early identification and treatment of ocular rosacea with associated dyslipidaemia and systemic inflammation. We posit that MGD in ocular rosacea sufferers may be a marker for dysregulated cholesterol synthesis and inflammation, and that statins maybe a potential therapy. This article introduces potential strategies to utilise ocular rosacea MGD as a possible marker for ophthalmologists, cardiologists, and primary healthcare physicians to treat rosacea-associated dyslipidaemia and systemic inflammation. This could aid in overall cardiovascular morbidity and mortality control for rosacea sufferers, potentially at an earlier age, while also addressing their tear film de-stabilisation through cholesterol lowering and inflammation reduction.
An Effective Resistive-Type Alcohol Vapor Sensor Using One-Step Facile Nanoporous Anodic Alumina
Authors: Chung Chen-Kuei , Ku Chin-An
Published: June 2023

With the increases in work environment regulations restricting alcohol to 1000 ppm, and in drink-driving laws, testing for alcohol with a simple method is a crucial issue. Conventional alcohol sensors based on sulfide, metal oxide, boron nitride or graphene oxide have a detection limit in the range of 50–1000 ppm but have disadvantages of complicated manufacture and longer processing times. A recent portable alcohol meter based on semiconductor material using conductivity or chemistry measurements still has the problem of a complex and lengthy manufacturing process. In this paper, a simple and effective resistive-type alcohol vapor sensor using one-step anodic aluminum oxide (AAO) is proposed. The nanoporous AAO was produced in one-step by anodizing low-purity AA1050 at room temperature of 25 °C, which overcame the traditional high-cost and lengthy process at low temperature of anodization and etching from high-purity aluminum. The highly specific surface area of AAO has benefits for good sensing performance, especially as a humidity or alcohol vapor sensor. With the resistance measurement method, alcohol vapor concentration of 0, 100, 300, 500, 700 and 1000 ppm correspond to mean resistances of 8524 Ω, 8672 Ω, 9121 Ω, 9568 Ω, 10,243 Ω, and 11,045 Ω, respectively, in a linear relationship. Compared with other materials for detecting alcohol vapor, the AAO resistive sensor has advantages of fast and simple manufacturing with good detection limits for practical applications. The resistive-type alcohol vapor-sensing mechanism is described with respect to the resistivity of the test substance and the pore morphology of AAO. In a human breath test, the AAO sensor can quickly distinguish whether the subject is drinking, with normal breath response of −30% to −40% and −20% to −30% response after drinking 50 mL of wine of 25% alcohol.
Deep Learning for Microfluidic-Assisted Caenorhabditis elegans Multi-Parameter Identification Using YOLOv7
Authors: Zhang Jie , Liu Shuhe , Yuan Hang , Yong Ruiqi , Duan Sixuan , Li Yifan , Spencer Joseph , Lim Eng Gee , Yu Limin , Song Pengfei
Published: June 2023

The Caenorhabditis elegans (C. elegans) is an ideal model organism for studying human diseases and genetics due to its transparency and suitability for optical imaging. However, manually sorting a large population of C. elegans for experiments is tedious and inefficient. The microfluidic-assisted C. elegans sorting chip is considered a promising platform to address this issue due to its automation and ease of operation. Nevertheless, automated C. elegans sorting with multiple parameters requires efficient identification technology due to the different research demands for worm phenotypes. To improve the efficiency and accuracy of multi-parameter sorting, we developed a deep learning model using You Only Look Once (YOLO)v7 to detect and recognize C. elegans automatically. We used a dataset of 3931 annotated worms in microfluidic chips from various studies. Our model showed higher precision in automated C. elegans identification than YOLOv5 and Faster R-CNN, achieving a mean average precision (mAP) at a 0.5 intersection over a union (mAP@0.5) threshold of 99.56%. Additionally, our model demonstrated good generalization ability, achieving an mAP@0.5 of 94.21% on an external validation set. Our model can efficiently and accurately identify and calculate multiple phenotypes of worms, including size, movement speed, and fluorescence. The multi-parameter identification model can improve sorting efficiency and potentially promote the development of automated and integrated microfluidic platforms.
Effect of Solder Layer Void Damage on the Temperature of IGBT Modules
Authors: Xu Pengpeng , Liu Peisheng , Yan Lei , Zhang Zhao
Published: June 2023

Solder layer void is one of the main failure causes of power semiconductor devices, which will seriously affect the reliability of the devices. In this study, a 3D model of IGBT (Insulated Gate Bipolar Transistor) packaging was built by DesignModeler. Based on ANSYS Workbench, the influence of void size, location, solder layer type, and thickness on the temperature distribution of the IGBT module was simulated. The results show that the larger the void radius, the higher the temperature of the IGBT module. The closer the void is to the center of the solder layer, the higher the temperature of the module. The void on the top corner of the solder layer had the greatest impact on the junction temperature of the IGBT module, and the shape of the void is also one of the factors that affect the temperature of the module. The denser the void distribution, the higher the temperature of the module. The temperature of the IGBT module was reduced from 62.656 °C to 59.697 °C by using nanosilver solder paste, and the overall heat dissipation performance of the module was improved by 5%. The temperature of the module increased linearly with the increase in solder layer thickness, and the temperature increased by 0.8 °C for every 0.025 mm increase in solder layer thickness. The simulation results have a guiding significance for improving the thermal stability of IGBT modules.
Numerical Solution of the Electric Field and Dielectrophoresis Force of Electrostatic Traveling Wave System
Authors: Yu Yue , Luo Yao , Cilliers Jan , Hadler Kathryn , Starr Stanley , Wang Yanghua
Published: June 2023

Electrostatic traveling wave (ETW) methods have shown promising performance in dust mitigation of solar panels, particle transport and separation in in situ space resource utilization, cell manipulation, and separation in biology. The ETW field distribution is required to analyze the forces applied to particles and to evaluate ETW design parameters. This study presents the numerical results of the ETW field distribution generated by a parallel electrode array using both the charge simulation method (CSM) and the boundary element method (BEM). A low accumulated error of the CSM is achieved by properly arranging the positions and numbers of contour points and fictitious charges. The BEM can avoid the inconvenience of the charge position required in the CSM. The numerical results show extremely close agreement between the CSM and BEM. For simplification, the method of images is introduced in the implementation of the CSM and BEM. Moreover, analytical formulas are obtained for the integral of Green’s function along boundary elements. For further validation, the results are cross-checked using the finite element method (FEM). It is found that discrepancies occur at the ends of the electrode array. Finally, analyses are provided of the electric field and dielectrophoretic (DEP) components. Emphasis is given to the regions close to the electrode surfaces. These results provide guidance for the fabrication of ETW systems for various applications.
Investigation of Cutting Force and the Material Removal Mechanism in the Ultrasonic Vibration-Assisted Scratching of 2D-SiCf/SiC Composites
Authors: Lin Hao , Zhou Ming , Wang Haotao , Bai Sutong
Published: June 2023

Ultrasonic-assisted grinding (UAG) is widely used in the manufacture of hard and brittle materials. However, the process removal mechanism was never elucidated and its potential is yet to be fully exploited. In this paper, the mechanism of material removal is analyzed by ultrasonic-assisted scratching. Three distinct surfaces (S1, S2, and S3) were selected on the basis of the braided and laminated structure of fiber bundles. The ultrasonic-assisted scratching experiment is carried out under different conditions, and the scratching force (SF) of the tested surface will fluctuate periodically. Under the conditions of different feed speeds, depths, and ultrasonic amplitudes, the normal scratching force (SFn) is greater than the tangential scratching force (SFt), and the average scratching force on the three surfaces is generally S3 > S2 >S1. Among the three processing parameters, the speed has the most significant influence on the scratching force, while the scratching depth has little influence on the scratching force. Under the same conditions and surface cutting mode, the ultrasonic vibration-assisted scratching force is slightly lower than the conventional scratching force. The scratching force decreases first and then increases with the amplitude of ultrasonic vibration. Because the fiber undergoes a brittle fracture in the ultrasonic-assisted scratching process, the matrix is torn, and the surface residues are discharged in time; therefore, the surface roughness is improved.
Review of Visual Measurement Methods for Metal Vaporization Processes in Laser Powder Bed Fusion
Authors: Liu Jiaqi , Wei Bin , Chang Hongjie , Li Jie , Yang Guang
Published: June 2023

Laser powder bed fusion (LPBF) is of great importance for the visual measurement and analysis of the metallization process, which is the process of solid, liquid, and gas phase transformations of metal powders under high-energy laser irradiation due to the low boiling point/high saturated vapor pressure. Since the evaporation of metals involves the interaction of driving forces such as vapor back pressure, surface tension, and gravity, the movement of the melt pool is not stable. At the same time, it also produces vaporization products such as vapor plumes and sprays, which cause defects such as bubbles, porosity, lack of fusion, inclusions, etc., during the manufacturing process of the parts, affecting the performance and manufacturing quality of the parts. More and more researchers are using imaging technologies, such as high-speed X-ray, high-speed visible light cameras, and high-speed schlieren imaging, to perform noncontact visual measurements and analyses of the melt pool, vapor plume, and spatter during the metal evaporation process, and the results show that the metal evaporation process can be suppressed by optimizing the process parameters and changing the processing atmosphere, thereby reducing part defects and improving part performance and built part quality. This paper reviews the research on metal evaporation mechanisms and visual measurement methods of metal evaporation, then discusses the measures of metal evaporation, and finally summarizes and prospects the future research hotspots of LPBF technology, according to the existing scholars’ research on numerical simulation analysis and visual measurement methods of the metal evaporation process.
Simplified Phenomenological Model for Ferroelectric Micro-Actuator
Authors: Nguyen Binh Huy , Torri Guilherme Brondani , Zunic Maja , Rochus Véronique
Published: June 2023

As smart structures are becoming increasingly ubiquitous in our daily life, the need for efficient modeling electromechanical coupling devices is also rapidly advancing. Smart structures are often made of piezoelectric materials such as lead zirconate titanate (PZT), which exhibits strong nonlinear behavior known as hysteresis effect under a large applied electric field. There have been numerous modeling techniques that are able to capture such an effect; some techniques are suitable for obtaining physical insights into the micro-structure of the material, while other techniques are better-suited to practical structural analyses. In this paper, we aim to achieve the latter. We propose a simplified phenomenological macroscopic model of a nonlinear ferroelectric actuator. The assumption is based on the direct relation between the irreversible strain and irreversible electric field, and the consequently irreversible polarization. The proposed model is then implemented in a finite element framework, in which the main features such as local return mapping and the tangent moduli are derived. The outcomes of the model are compared and validated with experimental data. Therefore, the development presented in this paper can be a useful tool for the modeling of nonlinear ferroelectric actuators.
Development and Performance Evaluation of Integrated Hybrid Power Module for Three-Phase Servo Motor Applications
Authors: Cheng Hsien-Chie , Liu Yan-Cheng , Lin Hsin-Han , Chiou Shian-Chiau , Tzeng Chih-Ming , Chang Tao-Chih
Published: June 2023

This study aims to develop a 30 kHz/12 kW silicon carbide (SiC)/Si integrated hybrid power module (iHPM) for variable frequency drive applications, particularly industrial servo motor control, and, additionally, to theoretically and experimentally assess its dynamic characteristics and efficiency during operation. This iHPM integrates a brake circuit, a three-phase Si rectifier, and a three-phase SiC inverter within a single package to achieve a minimal current path. A space-vector pulse width modulation (SVPWM) scheme is used to control the inverter power switches. In order to reduce parasitic inductance and power loss, an inductance cancellation design is implemented in the Si rectifier and SiC inverter. The switching transients and their parasitic effects during a three-phase operation are assessed through an electromagnetic-circuit co-simulation model, by which the power loss and efficiency of the iHPM are estimated. The modeled parasitic inductance of the inverter is validated through inductance measurement, and the effectiveness of the simulated results in terms of switching transients and efficiency is verified using the experimental results of the double pulse test and open-loop inverter operation, respectively. In addition, the power loss and efficiency of the SiC MOSFET inverter are experimentally compared against those of a commercial Si IGBT inverter.
The Truman Show for Human Helminthic Parasites: A Review of Recent Advances in In Vitro Cultivation Platforms
Authors: Sutrave Smita , Richter Martin Heinrich
Published: June 2023

Throughout history, parasites and parasitic diseases have been humankind’s constant companions, as evidenced by the findings of tapeworm eggs in ancient, mummified remains. Helminths are responsible for causing severe, long-term, and debilitating infectious diseases worldwide, especially affecting economically challenged nations due to prevailing deficits in access to sanitation, proper hygiene practices, and healthcare infrastructure. Socio-ecological drivers, such as poverty, migration, and climate change, continue to contribute to parasites and their disease vectors being spread beyond known endemic zones. The study of parasitic diseases has had a fair amount of success leading to the development of new chemotherapeutic agents and the implementation of parasite eradication programs. However, further progress in this direction has been hampered by the challenges of culturing some of these parasites in in vitro systems for efficient availability, basic life cycle, infection studies, and effectiveness of novel treatment strategies. The complexity of the existing models varies widely, depending on the parasite and its life cycle, ranging from basic culture methods to advanced 3D systems. This review aims to highlight the research conducted so far in culturing and maintaining parasites in an in vitro setting, thereby contributing to a better understanding of pathogenicity and generating new insights into their lifecycles in the hopes of leading to effective treatments and prevention strategies. This work is the first comprehensive outline of existing in vitro models for highly transmissible helminth diseases causing severe morbidity and mortality in humans globally.
A Tale about Shigella: Evolution, Plasmid, and Virulence
Authors: Haidar-Ahmad Nathaline , Manigat France Ourida , Silué Navoun , Pontier Stéphanie M. , Campbell-Valois François-Xavier
Published: June 2023

Shigella spp. cause hundreds of millions of intestinal infections each year. They target the mucosa of the human colon and are an important model of intracellular bacterial pathogenesis. Shigella is a pathovar of Escherichia coli that is characterized by the presence of a large invasion plasmid, pINV, which encodes the characteristic type III secretion system and icsA used for cytosol invasion and cell-to-cell spread, respectively. First, we review recent advances in the genetic aspects of Shigella, shedding light on its evolutionary history within the E. coli lineage and its relationship to the acquisition of pINV. We then discuss recent insights into the processes that allow for the maintenance of pINV. Finally, we describe the role of the transcription activators VirF, VirB, and MxiE in the major virulence gene regulatory cascades that control the expression of the type III secretion system and icsA. This provides an opportunity to examine the interplay between these pINV-encoded transcriptional activators and numerous chromosome-encoded factors that modulate their activity. Finally, we discuss novel chromosomal genes icaR, icaT, and yccE that are regulated by MxiE. This review emphasizes the notion that Shigella and E. coli have walked the fine line between commensalism and pathogenesis for much of their history.
Immunostimulatory Activity of Lactococcus lactis subsp. lactis CAB701 Isolated from Jeju Cabbage
Authors: Jeong Huijin , Kim Suin , Hwang Un-Sik , Choi Hyukjoon , Park Young-Seo
Published: June 2023

This study explored the potential of Lactococcus lactis subsp. lactis CAB701 as a probiotic strain, focusing on its immunostimulatory properties. Despite adverse conditions in the gastrointestinal environment, this strain exhibited remarkable survivability, as evidenced by its tolerance to acid, bile, and pancreatin, coupled with its impressive ability to adhere to Caco-2 cells. It also exhibited significant antioxidant activity, similar to the established probiotic Lacticaseibacillus rhamnosus GG (LGG). Our research elucidates the potent immunostimulatory effects of L. lactis subsp. lactis CAB701. This strain significantly enhanced nitric oxide production in RAW 264.7, far exceeding that obtained with LGG. An in-depth examination revealed elevated expression of key inflammatory mediators, including inducible nitric oxide synthase, tumor necrosis factor-alpha, cyclooxygenase-2, interleukin (IL)-1 beta, and IL-6. L. lactis subsp. lactis CAB701 increases the expression of critical signaling proteins in the mitogen-activated protein kinase pathway. This prompted a substantial increase in the expression of phosphorylated c-Jun N-terminal kinases and extracellular signal-regulated kinases, suggesting their role in modulating these immune-related pathways. Overall, these findings demonstrate the significant immunostimulatory capacity of L. lactis subsp. lactis CAB701, positioning it as a potential candidate for probiotic use, especially in applications that enhance immune responses.
Novel Insights into the Mechanisms of Microbial Transcription and Translation
Authors: Sarin L. Peter
Published: June 2023

For the better part of the century, microbes have been a treasure trove for deciphering the inner workings of the cell, from early insights into DNA replication and restriction-enzyme-mediated antiviral responses, to unravelling the complexities of metabolic pathways and understanding gene expression and its regulatory mechanisms [...]
Use of an Innovative Silage of Agro-Industrial Waste By-Products in Pig Nutrition: A Pilot Study of Its Effects on the Pig Gastrointestinal Microbiota
Authors: Skoufos Ioannis , Nelli Aikaterini , Venardou Brigkita , Lagkouvardos Ilias , Giannenas Ilias , Magklaras Georgios , Zacharis Christos , Jin Lizhi , Wang Jin , Gouva Evangelia , Skoufos Stylianos , Bonos Eleftherios , Tzora Athina
Published: June 2023

The aim of this study was to evaluate whether dietary supplementation with an innovative silage (IS) created using 60% olive mill waste, 20% grape pomace, and 20% deproteinised feta cheese waste solids can modulate the composition of the intestinal microbiota in weaned (Exp. 1) and finishing (Exp. 2) pigs. In Exp. 1 (40 day supplementation), forty-five crossbred weaned pigs were randomly assigned to the 0% (Control), 5%, or 10% IS groups (15 replicates/experimental diet). In Exp. 2 (60 day supplementation), eighteen finishing pigs from Exp. 1 were fed the control diet for 8 weeks before being re-assigned to their original experimental groups and fed with the 0% (Control), 5%, or 10% IS diets (six replicates/experimental diet). Performance parameters were recorded. Ileal and caecal digesta and mucosa were collected at the end of each experiment for microbiota analysis using 16S rRNA gene sequencing (five pigs/experimental diet for Exp. 1 and six pigs/experimental diet for Exp. 2). No significant effects on pig growth parameters were observed in both experiments. In Exp. 1, 5% IS supplementation increased the relative abundance of the Prevotellaceae family, Coprococcus genus, and Alloprevotella rava (OTU_48) and reduced the relative abundance of Lactobacillus genus in the caecum compared to the control and/or 10% IS diets (p < 0.05). In Exp. 2, 5% IS supplementation led to compositionally more diverse and different ileal and caecal microbiota compared to the control group (p < 0.05; p = 0.066 for β-diversity in ileum). Supplementation with the 5% IS increased the relative abundance of Clostridium celatum/disporicum/saudiense (OTU_3) in the ileum and caecum and Bifidobacterium pseudolongum (OTU_17) in the caecum and reduced the relative abundance of Streptococcus gallolyticus/alactolyticus (OTU_2) in the caecum compared to the control diet (p < 0.05). Similar effects on C. celatum/disporicum/saudiense and S. gallolyticus/alactolyticus were observed with the 10% IS diet in the caecum (p < 0.05). IS has the potential to beneficially alter the composition of the gastrointestinal microbiota in pigs.
Clinoptilolite—An Efficient Carrier for Catalytically Active Nano Oxide Particles
Authors: Pavlović Jelena , Rajić Nevenka
Published: June 2023

Many efforts have been devoted to produce green materials and technology to prevent and minimize the adverse effects on the environment and human health caused primarily by population growth and industrial progress. Over the past years, the use of zeolites has attracted considerable attention as both an economically and environmentally friendly option. Zeolites are crystalline, hydrated aluminosilicates with an open-framework structure. Unique structural features make them very useful ion-changers, adsorbents and catalysts. The catalytic use of zeolites has expanded from traditional use in the petrochemical industry and refineries to use in the catalytic degradation of various environmental pollutants and the synthesis of fine chemicals. In recent times, progress on the use of zeolites has been achieved in biomass conversion to fuels and valuable industrial bio-based chemicals. This review highlights the recent advances in the catalytic application of clinoptilolite (CLI), the most abundant and explored natural zeolite. The main goal of the review is to give the current state of CLI applications and insights into CLI catalytic performance, which opens possibilities for a variety of applications.
Study of the Mechanism of Dearsenification of Arsenopyrite Enhanced by Mechanically Modified Pyrite and Bacteria
Authors: Chen Yajing , Yang Hongying , Chen Guomin , Tong Linlin , Zhang Shuo
Published: June 2023

This study investigated the impact of mechanically modified pyrite on the dearsenification of arsenopyrite through bacterial oxidation. Pyrite was mechanically modified using a planetary high-energy ball mill, and the resulting changes in the crystal structure were characterized using particle size analysis, specific surface area measurements, scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD). Pearson correlation analysis was employed to examine the relationship between the crystal structure of modified pyrite and the bacterial oxidation of arsenopyrite. The study also investigated the mechanism of arsenic removal using pyrite with varying degrees of mechanical modification during arsenopyrite bio-oxidation. The key findings are as follows: (1) The maximum extent of arsenopyrite dearsenification by bacteria was achieved at a pyrite modification degree of 400 r·min−1 and reached 96.01%, which was 14.49% higher than that for unmodified pyrite and 24.13% higher than that in the absence of pyrite. At this degree, the modified pyrite exhibited a median diameter of 1.33 μm (minimum) and a specific surface area of 3123 m2·kg−1 (maximum). (2) Pearson correlation analysis revealed a significant negative correlation between the extent of arsenopyrite dearsenification and the particle size and grain size of pyrite, and a significant positive correlation with the specific surface area and the amorphous degree of pyrite. A smaller particle size and grain size, larger specific surface area, and a higher amorphous degree were associated with a higher extent of dearsenification. (3) The mechanism of enhanced arsenopyrite dearsenification using mechanically modified pyrite was attributed to autocatalytic dissolution. The galvanic effect directly enhanced dearsenification, while the mechanical modification facilitated the direct oxidation of pyrite by bacteria, releasing a significant amount of Fe3+ and indirectly enhancing the dearsenification of arsenopyrite.
Three-Dimensional Electromagnetic Imaging of Geothermal System in Gonghe Basin
Authors: Yang Yi , Wang Xuben , Liang Mingxing , Jiang Zhengzhong , Ou Yang , Tang Xianchun , Li Xufeng , Qiu Liquan , Liang Meng , Liu Dongming , Zhang Jie
Published: June 2023

To better understand the geothermal system of the Gonghe Basin, we deployed 471 magnetotelluric survey points with an average distance of 2~3 km, covering the eastern and southern areas of the Basin. We used ModEM inversion software to carry out 3D inversion of 431 survey points and established a 3D-electrical model at a depth of 50 km in the area. The resistivity model shows that the low resistivity in the shallow part of the basin is related to the Cenozoic loose sedimentary cover, while the resistivity values of the mountains around the basin and the magmatic rock uplift zone are higher. The electrical model also shows that the high-conductivity layer is widely distributed in the middle and lower crust (15~35 km) of the basin, and direction of the high-conductivity layer is consistent with that of NW–SE fault in the basin. These high-conductivity layers may be the principal reason for the high heat flow values in the Gonghe Basin. Our resistivity model also shows that there is an obvious discontinuity between high- and low-resistivity blocks at different depths in the middle and upper crust. These discontinuities are consistent with the faults observed on the surface, which are related to the strong topographic relief. Our electrical model shows that these faults in the middle and upper crust are connected with the high-conductivity layer as the channel of heat transfer to the shallow part. Finally, the heat energy is enriched in the Triassic granite to form dry hot rock (HDR). The 3D-magnetotelluric imaging results depict the 3D-distribution characteristics of the geothermal system in the eastern and southern parts of the Gonghe Basin.
Tomographic Imaging of Bauxite Grains Leached Using Hydrochloric Acid
Authors: Razavi Anita , Stein Alena , Quirmbach Peter
Published: June 2023

X-ray computer tomography (XRT) is a three-dimensional, nondestructive, and thus reproducible examination method that allows for the investigation of internal and external structures of objects. Due to its characteristics, the XRT technique has increasingly established itself as an alternative examination method and is also applied in the field of mineral processing. Within this work, XRT is used to investigate the influence of hydrochloric acid leaching of iron-rich bauxites on grain composition. Acid leaching is a promising method for the beneficiation of iron-rich bauxites for refractories. Many studies have already established that leaching with hydrochloric acid can reduce the Fe2O3 content in bauxites. However, apart from the influence of the leaching process on the composition of the bauxites, aspects such as the influence of the acid on the exact grain constitution or the porosity behavior have rarely been considered so far. To address these open questions, XRT analysis was used to examine and characterize various bauxites. By comparing identical grains before and after leaching, it was observed that in gibbsite bauxites the acid penetration is deeper, and the volume decreases significantly. In diasporic and boehmitic bauxites, clear leaching edges can be seen in which the iron content has been reduced.
Structural and Thermodynamic Properties of Magnesium-Rich Liquids at Ultrahigh Pressure
Authors: González-Cataldo Felipe , Militzer Burkhard
Published: June 2023

We explore the structural properties of Mg, MgO, and MgSiO3 liquids from ab initio computer simulations at conditions that are relevant for the interiors of giant planets, stars, shock compression measurements, and inertial confinement fusion experiments. Using path-integral Monte Carlo and density functional theory molecular dynamics, we derive the equation of state of magnesium-rich liquids in the regime of condensed and warm dense matter, with densities ranging from 0.32 to 86.11 g cm−3 and temperatures from 20,000 K to 5 × 108 K. We study the electronic structure of magnesium as a function of density and temperature and the correlations of the atomic motion, finding an unexpected local maximum in the pair correlation functions that emerges at high densities which decreases the coordination number of elemental magnesium and reveals a higher packing. This phenomenon is not observed in other magnesium liquids, which maintain a rather constant coordination number.
Trade Networks in the Neighbouring Roman Provinces of Aquitania-Tarraconensis on the Bay of Biscay: Evidence from Petrographic and Chemical Analyses of Common Coarse Ware Pottery
Authors: Alonso-Olazabal Ainhoa , Zuluaga Maria Cruz , Martínez-Salcedo Ana , Esteban-Delgado Milagros , Izquierdo-Marculeta Maria Teresa , Rechin François , Ortega Luis Ángel
Published: June 2023

Common non-wheel-thrown Roman pottery from the southern Aquitania and north-eastern of Tarraconensis provinces (CNT-AQTA) of the Early and Later Roman Empire (1st to 5th centuries AD) has been studied. Petrological, mineralogical, and chemical analyses were conducted to contrast with the archaeological study of the pottery. The chemical composition of many pottery samples displays different patterns of burial chemical modification, limiting their use for provenance and diffusion studies. Particular emphasis has been paid to the petrographic features of the fabrics, as they do not change during burial, reflecting the nature of the raw material and making it possible to identify the provenance areas of the raw materials. Around the Bay of Biscay, the same pottery tradition continued in the neighbouring provinces during Roman times. Petrographic studies make it possible to determine the distribution of pottery and the changes in trade networks during the Roman period across the area of the Bay of Biscay being studied.
Experimental Verification for the Graphitization of Inertinite
Authors: Liu Zhifei , Cao Daiyong , Chen Gaojian , Bi Zhongwei , Chen Qingtong
Published: June 2023

In order to explore the graphitization of inertinite, this paper conducted high-temperature thermal simulation experiments (HTT) and high-temperature high-pressure simulation experiments (HTHP) on isolated samples enriched in inertinite. X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM) were used to analyze the graphitization process of inertinite. ① Results of HTT: the graphitization of inertinite has a “threshold condition” with the temperature threshold ranging between 2100 °C and 2400 °C. Below this threshold, the d002 value of the samples remains above 0.342 nm. ② Results of HTHP: (i) External forces have a significant positive effect on the graphitization of inertinite. Compared to the HTT, the addition of external forces significantly reduces the temperature required for inertinite graphitization. (ii) Proper combinations of temperature and pressure conditions are crucial for efficiently promoting the graphitization of inertinite. Changes in pressure, either increasing or decreasing from the optimal pressure, have a suppressive effect on the graphitization of inertinite. ③ The mechanism of external forces on the graphitization of inertinite was analyzed. Shear stress promotes the rotation and orientation of aromatic layers, while static hydrostatic pressure contributes to the contraction and reduction of interlayer spacing in carbon layers.
S-Ethyl-Isothiocitrullin-Based Dipeptides and 1,2,4-Oxadiazole Pseudo-Dipeptides: Solid Phase Synthesis and Evaluation as NO Synthase Inhibitors
Authors: Mauchauffée Elodie , Leroy Jérémy , Chamcham Jihanne , Ejjoummany Abdelaziz , Maurel Manon , Nauton Lionel , Ramassamy Booma , Mezghenna Karima , Boucher Jean-Luc , Lajoix Anne-Dominique , Hernandez Jean-François
Published: June 2023

We previously reported dipeptidomimetic compounds as inhibitors of neuronal and/or inducible NO synthases (n/iNOS) with significant selectivity against endothelial NOS (eNOS). They were composed of an S-ethylisothiocitrullin-like moiety linked to an extension through a peptide bond or a 1,2,4-oxadiazole link. Here, we developed two further series where the extension size was increased to establish more favorable interactions in the NOS substrate access channel. The extension was introduced on the solid phase by the reductive alkylation of an amino-piperidine moiety or an aminoethyl segment in the case of dipeptide-like and 1,2,4-oxadiazole compounds, respectively, with various benzaldehydes. Compared to the previous series, more potent inhibitors were identified with IC50 in the micromolar to the submicromolar range, with significant selectivity toward nNOS. As expected, most compounds did not inhibit eNOS, and molecular modeling was carried out to characterize the reasons for the selectivity toward nNOS over eNOS. Spectral studies showed that compounds were interacting at the heme active site. Finally, selected inhibitors were found to inhibit intra-cellular iNOS and nNOS expressed in RAW264.7 and INS-1 cells, respectively.