bluuebunny/crossref_metadata_2025 huggingface dataset:
ADORA2A rs5760423 and CYP1A2 rs762551 Polymorphisms as Risk Factors for Parkinson’s Disease
Authors: Siokas Vasileios , Aloizou Athina-Maria , Tsouris Zisis , Liampas Ioannis , Liakos Panagiotis , Calina Daniela , Docea Anca Oana , Tsatsakis Aristidis , Bogdanos Dimitrios P. , Hadjigeorgiou Georgios M. , Dardiotis Efthimios
Published: January 2021

Background: Parkinson’s disease (PD) is the second commonest neurodegenerative disease. The genetic basis of PD is indisputable. Both ADORA2A rs5760423 and CYP1A2 rs762551 have been linked to PD, to some extent, but the exact role of those polymorphisms in PD remains controversial. Objective: We assessed the role of ADORA2A rs5760423 and CYP1A2 rs762551 on PD risk. Methods: We genotyped 358 patients with PD and 358 healthy controls for ADORA2A rs5760423 and CYP1A2 rs762551. We also merged and meta-analyzed our data with data from previous studies, regarding these two polymorphisms and PD. Results: No significant association with PD was revealed (p > 0.05), for either ADORA2A rs5760423 or CYP1A2 rs762551, in any of the examined genetic model of inheritance. In addition, results from meta-analyses yield negative results. Conclusions: Based on our analyses, it appears rather unlikely that ADORA2A rs5760423 or CYP1A2 rs762551 is among the major risk factors for PD, at least in Greek patients with PD.
Do-(Not-)Mechanical-Circulatory-Support Orders: Should We Ask All Cardiac Surgery Patients for Informed Consent for Post-Cardiotomy Extracorporeal Life Circulatory Support?
Authors: Simons Jorik , Suverein Martje , van Mook Walther , Caliskan Kadir , Soliman Osama , van de Poll Marcel , Delnoij Thijs , Maessen Jos , Mees Barend , Lorusso Roberto
Published: January 2021

Post-cardiotomy extracorporeal life support (PC-ECLS) has seen a substantial increase in use over the past 10 years. PC-ECLS can be a life-saving procedure and is mostly applied in the presence of unexpected, severe cardio-respiratory complication. Despite PC-ECLS being critical in allowing for organ recovery, it is unfortunately closely connected with an unpredictable outcomes, high morbidity, and, even in the case of cardiac function improvement, potential sustained disabilities that have a life-changing impact for the patient and his or her family. Since the decision to start PC-ECLS is made in an acute setting, there is often only limited or no time for self-determined choices. Due to the major impact of the intervention, it would be highly desirable to obtain informed consent before starting PC-ECLS, since the autonomy of the patient and shared-decision making are two of the most important ethical values in modern medicine. Recent developments regarding awareness of the impacts of a prolonged intensive care stay make this a particularly relevant topic. Therefore, it would be desirable to develop a structural strategy that takes into account the likelihood of such an intervention and the wishes and preferences of the patient, and thus the related autonomy of the patient. This article proposes key points for such a strategy in the form of a PC-ECLS informed consent, a do-(not-)mechanical-circulatory-support order (D(N)MCS), and specific guidelines to determine the extent of the shared decision making. The concept presented in this article could be a starting point for improved and ethical PC-ECLS treatment and application.
Accuracy of Guided Implant Surgery in the Edentulous Jaw Using Desktop 3D-Printed Mucosal Supported Guides
Authors: D’haese Rani , Vrombaut Tom , Hommez Geert , De Bruyn Hugo , Vandeweghe Stefan
Published: January 2021

Purpose: The aim of this in vitro study is to evaluate the accuracy of implant position using mucosal supported surgical guides, produced by a desktop 3D printer. Methods: Ninety implants (Bone Level Roxolid, 4.1 mm × 10 mm, Straumann, Villerat, Switzerland) were placed in fifteen mandibular casts (Bonemodels, Castellón de la Plana, Spain). A mucosa-supported guide was designed and printed for each of the fifteen casts. After placement of the implants, the location was assessed by scanning the cast and scan bodies with an intra-oral scanner (Primescan®, Dentsply Sirona, York, PA, USA). Two comparisons were performed: one with the mucosa as a reference, and one where only the implants were aligned. Angular, coronal and apical deviations were measured. Results: The mean implant angular deviation for tissue and implant alignment were 3.25° (SD 1.69°) and 2.39° (SD 1.42°) respectively, the coronal deviation 0.82 mm (SD 0.43 mm) and 0.45 mm (SD 0.31 mm) and the apical deviation 0.99 mm (SD 0.45 mm) and 0.71 mm (SD 0.43 mm). All three variables were significantly different between the tissue and implant alignment (p < 0.001). Conclusion: Based on the results of this study, we conclude that guided implant surgery using desktop 3D printed mucosa-supported guides has a clinically acceptable level of accuracy. The resilience of the mucosa has a negative effect on the guide stability and increases the deviation in implant position.
A Study on the Effectiveness of the Heading Control on the Mooring Line Tension and Position Offset for an Arctic Floating Structure under Complex Environmental Loads
Authors: Kang Hyun Hwa , Lee Dae-Soo , Lim Ji-Su , Lee Seung Jae , Jang Jinho , Jung Kwang Hyo , Lee Jaeyong
Published: January 2021

Even though interest in developing the Arctic region is increasing continuously, the standard procedure to be used to analyze the station-keeping performance of a floater considering ice loads has not been established yet. In this paper, the effectiveness of heading control with a dynamic positioning system is analyzed to evaluate the improvement of the performance of the station-keeping system in the ice conditions. Complex environmental loads with ice-induced forces were generated and applied to a ship type floater with dynamic positioning and mooring systems. Three-hour time-domain simulations were conducted for the two different station-keeping systems with mooring only and mooring with a dynamic positioning system. Position offsets and mooring line tensions for the two scenarios were compared with maximum values and most probable maxima (MPM) values. The results of the simulation showed that the heading control can reduce 8.2% of MPM values for the mooring lines and improve the station-keeping performance by about 16.3%. The validity of the station-keeping system that was designed was confirmed, and it is expected that the specification of mooring lines can be relaxed with the heading control.
Significant Differences in Intestinal Microbial Communities in Aquatic Animals from an Aquaculture Area
Authors: Sun Fulin , Xu Zhantang
Published: January 2021

While much attention has been given to the role of animal intestinal microbes, few studies have focused on microbial communities and associated functions in cultured aquatic animals. In this study, high–throughput sequencing was used to analyze intestinal microbial communities and functions in fish, shrimp, crab and razor clams. Alpha diversity analyses showed significant differences in intestinal microbial diversity amongst these aquatic animals, and that shrimp intestines harbored the highest diversity and species numbers. T–test analyses (p < 0.05) showed significant differences in dominant microbial operational taxonomic units (OTUs) between all aquatic animals. Predominant intestinal bacteria included; Gammaproteobacteria, Fusobacteria, Mollicutes, Spirochaetia, Cyanobacteria, Bacteroidia and Bacilli. Similarly, anaerobic bacteria were highly diverse in animal intestines and included; Vibrio, Photobacterium, Cetobacterium, Propionigenium, Candidatus Hepatoplasma, Paraclostridium, and Lactobacillus. Principal co–ordinate analysis indicated that the distribution characteristics of intestinal microbes varied with animal species; in particular, we observed a high variability among shrimp intestinal samples. This variability indicated these genera had suitability for the different intestinal environment. Function prediction analysis indicated significant differences amongst different animals in the major functional groups, and that microbial functional profiles were strongly shaped by the intestinal environment. Thus, this study provides an important reference for future studies investigating crosstalk between aquatic animal hosts and their intestinal microbiota.
Does the Design of Stablecoins Impact Their Volatility?
Authors: Jarno Klaudia , Kołodziejczyk Hanna
Published: January 2021

In this paper, we shall compare the average volatility that characterises the main stablecoin design types with a view to answering the question of whether all stablecoin designs accomplish the goal of minimising their price fluctuations to the same degree. Our research is motivated by the lack of rigorous studies comparing volatility of different stablecoin types stressed in the literature as well as the practical importance of such a comparison from the investors’ viewpoint. We opted for a standard volatility measure, i.e., standard deviation of return rates, corrected it for autocorrelation, and detected differences between distributions of the measure in three stablecoin groups using various non-parametric tests, i.e., the Kruskal–Wallis test, the bootstrap F-test, post-hoc tests and non-parametric contrasts. We proved that stablecoins do not deliver equally on the promise to provide stable market value with tokenised funds being leaders. Tokenised funds design involves complete coverage of the stablecoin supply in units of the currency of reference as well as great dependence on the trusted third-party acting as a trustee for the collateral. Our study reveals that existing complex stablecoins designs hardly compete with this simple design in terms of volatility.
CdS Dots, Rods and Platelets—How to Obtain Predefined Shapes in a One-Pot Synthesis of Nanoparticles
Authors: Woznica Hanna , Banski Mateusz , Podhorodecki Artur
Published: January 2021

In recent years, numerous protocols for nanoplatelet synthesis have been developed. Here, we present a facile, one-pot method for controlling cadmium sulfide (CdS) nanoparticles’ shape that allows for obtaining zero-dimensional, one-dimensional, or two-dimensional structures. The proposed synthesis protocol is a simple heating-up approach and does not involve any inconvenient steps such as injection and/or pouring the precursors at elevated temperatures. Because of this, the synthesis protocol is highly repeatable. A gradual increase in the zinc acetate concentration causes the particles’ shape to undergo a transition from isotropic quantum dots through rods to highly anisotropic nanoplatelets. We identified conditions at which synthesized platelets were purely five monolayers thick. All samples acquired during different stages of the reaction were characterized via optical spectroscopy, which allowed for the identification of the presence of high-temperature, magic-size clusters prior to the platelets’ formation.
Carbon Monoxide Oxidation over Gold Nanoparticles Deposited onto Alumina Film Grown on Mo(110) Substrate: An Effect of Charge Tunneling through the Oxide Film
Authors: Magkoev Tamerlan
Published: January 2021

Formation of gold nanosized particles supported by aluminum oxide film grown on Mo(110) substrate and oxidation of carbon monoxide molecules on their surface have been in-situ studied in ultra-high vacuum by means of Auger electron spectroscopy (AES), reflection-absorption infrared spectroscopy (RAIRS), low energy electron diffraction (LEED), atomic force microscopy (AFM), temperature-programmed desorption (TPD), and work function measurements. The main focus was to follow how the thickness of the alumina film influences the efficiency of CO oxidation in an attempt to find out evidence of the possible effect of electron tunneling between the metal substrate and the Au particle through the oxide interlayer. Providing the largest degree of surface identity of the studied metal/oxide system at different thicknesses of the alumina film (two, four, six, and eight monolayers), it was found that the CO oxidation efficiency, defined as CO2 to CO TPD peaks intensity ratio, exponentially decays with the oxide film thickness growth. Taking into account the known fact that the CO oxidation efficiency depends on the amount of excess charge acquired by Au particle, the latter suggests that electron tunneling adds efficiency to the oxidation process, although not significantly.
Case Report: Massive Spontaneous Pneumothorax—A Rare Form of Presentation for Severe COVID-19 Pneumonia
Authors: Marza Adina Maria , Petrica Alina , Buleu Florina Nicoleta , Mederle Ovidiu Alexandru
Published: January 2021

Background and Objectives: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a viral disease that is spreading worldwide and became a pandemic. Although most of the time, the symptoms of the infection are flu like, a percentage of patients develop severe forms, along with severe complications. Many of them are known among front-line health workers, but the number of uncommon presentations and complications has increased. This case report aims to alert healthcare workers on less common forms of presentation, and to introduce this differential diagnosis in the evaluation of patients with COVID-19, given the increasing occurrence of pneumothorax in patients who are not mechanical ventilated. Case presentation: A 57-year-old female patient came to the Emergency Department (ED) by ambulance, with acute respiratory failure. She had SpO2 (peripheral O2 saturation ) = 43% on room air at home, and 86% on admission in ED after oxygen delivery (on a reservoir mask). SARS-CoV-2 infection was suspected based on symptoms that started three days ago (fever, dry cough, dyspnea, and fatigability). Blood was taken for lab tests, pharyngeal and nasal swabs for the reverse transcription–PCR (RT-PCR) test, and native computed tomography (CT) was scheduled. The thoracic CT scan showed massive right pneumothorax, partially collapsed lung, multiple bilateral lung infiltrates with a ground glass aspect and the RT-PCR test came back positive for SARS-CoV-2 infection. Despite the prompt diagnosis and treatment of pneumothorax (thoracostomy was performed and the drain tube was placed), the patient died after a long hospitalization in the intensive care unit. Conclusion: Secondary spontaneous pneumothorax (SSP), as a complication in severe forms of COVID-19 pneumonia, especially in female patients without risk factors is rare, and early diagnosis and treatment are essential for increasing the survival chances of these patients.
The Role of Complement System and the Immune Response to Tuberculosis Infection
Authors: Jagatia Heena , Tsolaki Anthony G.
Published: January 2021

The complement system orchestrates a multi-faceted immune response to the invading pathogen, Mycobacterium tuberculosis. Macrophages engulf the mycobacterial bacilli through bacterial cell surface proteins or secrete proteins, which activate the complement pathway. The classical pathway is activated by C1q, which binds to antibody antigen complexes. While the alternative pathway is constitutively active and regulated by properdin, the direct interaction of properdin is capable of complement activation. The lectin-binding pathway is activated in response to bacterial cell surface carbohydrates such as mannose, fucose, and N-acetyl-d-glucosamine. All three pathways contribute to mounting an immune response for the clearance of mycobacteria. However, the bacilli can reside, persist, and evade clearance by the immune system once inside the macrophages using a number of mechanisms. The immune system can compartmentalise the infection into a granulomatous structure, which contains heterogenous sub-populations of M. tuberculosis. The granuloma consists of many types of immune cells, which aim to clear and contain the infection whilst sacrificing the affected host tissue. The full extent of the involvement of the complement system during infection with M. tuberculosis is not fully understood. Therefore, we reviewed the available literature on M. tuberculosis and other mycobacterial literature to understand the contribution of the complement system during infection.
MEMS Membranes with Nanoscale Holes for Analytical Applications
Authors: Bagolini Alvise , Correale Raffaele , Picciotto Antonino , Di Lorenzo Maurizio , Scapinello Marco
Published: January 2021

Micro-electro-mechanical membranes having nanoscale holes were developed, to be used as a nanofluidic sample inlet in novel analytical applications. Nanoscopic holes can be used as sampling points to enable a molecular flow regime, enhancing the performance and simplifying the layout of mass spectrometers and other analytical systems. To do this, the holes must be placed on membranes capable of consistently withstanding a pressure gradient of 1 bar. To achieve this goal, a membrane-in-membrane structure was adopted, where a larger and thicker membrane is microfabricated, and smaller sub-membranes are then realized in it. The nanoscopic holes are opened in the sub-membranes. Prototype devices were fabricated, having hole diameters from 300 to 600 nm, a membrane side of 80 μm, and a simulated maximum displacement of less than 150 nm under a 1 bar pressure gradient. The obtained prototypes were tested in a dedicated vacuum system, and a method to calculate the effective orifice diameter using gas flow measurements at different pressure gradients was implemented. The calculated diameters were in good agreement with the target diameter sizes. Micro-electro-mechanical technology was successfully used to develop a novel micromembrane with nanoscopic holes, and the fabricated prototypes were successfully used as a gas inlet in a vacuum system for mass spectrometry and other analytical systems.
Prediction of Microstructure Constituents’ Hardness after the Isothermal Decomposition of Austenite
Authors: Smokvina Hanza Sunčana , Smoljan Božo , Štic Lovro , Hajdek Krunoslav
Published: January 2021

An increase in technical requirements related to the prediction of mechanical properties of steel engineering components requires a deep understanding of relations which exist between microstructure, chemical composition and mechanical properties. This paper is dedicated to the research of the relation between steel hardness with the microstructure, chemical composition and temperature of isothermal decomposition of austenite. When setting the equations for predicting the hardness of microstructure constituents, it was assumed that: (1) The pearlite hardness depends on the carbon content in a steel and on the undercooling below the critical temperature, (2) the martensite hardness depends primarily on its carbon content, (3) the hardness of bainite can be between that of untempered martensite and pearlite in the same steel. The equations for estimation of microstructure constituents’ hardness after the isothermal decomposition of austenite have been proposed. By the comparison of predicted hardness using a mathematical model with experimental results, it can be concluded that hardness of considered low-alloy steels could be successfully predicted by the proposed model.
Additive Manufactured 316L Stainless-Steel Samples: Microstructure, Residual Stress and Corrosion Characteristics after Post-Processing
Authors: Santa-aho Suvi , Kiviluoma Mika , Jokiaho Tuomas , Gundgire Tejas , Honkanen Mari , Lindgren Mari , Vippola Minnamari
Published: January 2021

Additive manufacturing (AM) is a relatively new manufacturing method that can produce complex geometries and optimized shapes with less process steps. In addition to distinct microstructural features, residual stresses and their formation are also inherent to AM components. AM components require several post-processing steps before they are ready for use. To change the traditional manufacturing method to AM, comprehensive characterization is needed to verify the suitability of AM components. On very demanding corrosion atmospheres, the question is does AM lower or eliminate the risk of stress corrosion cracking (SCC) compared to welded 316L components? This work concentrates on post-processing and its influence on the microstructure and surface and subsurface residual stresses. The shot peening (SP) post-processing levelled out the residual stress differences, producing compressive residual stresses of more than −400 MPa in the AM samples and the effect exceeded an over 100 µm layer below the surface. Post-processing caused grain refinement and low-angle boundary formation on the sample surface layer and silicon carbide (SiC) residue adhesion, which should be taken into account when using the components. Immersion tests with four-point-bending in the heated 80 °C magnesium chloride solution for SCC showed no difference between AM and reference samples even after a 674 h immersion.
Study on the Dissolution and Precipitation Behavior of Self-Designed (NbTi)C Nanoparticles Addition in 1045 Steel
Authors: Zhu Hongwei , Li Haonan , Xiao Furen , Gao Zhixiang
Published: January 2021

Self-designed (NbTi)C nanoparticles were obtained by mechanical alloying, predispersed in Fe powder, and then added to 1045 steel to obtain modified cast steels. The microstructure of cast steels was investigated by an optical microscope, scanning electron microscope, X-ray diffraction, and a transmission electron microscope. The results showed that (NbTi)C particles can be added to steels and occur in the following forms: original ellipsoidal morphology nanoparticles with uniform dispersion in the matrix, cuboidal nanoparticles in the grain, and microparticles in the grain boundary. Calculations by Thermo-Calc software and solubility formula show that cuboidal (NbTi)C nanoparticles were precipitated in the grain, while the (NbTi)C microparticles were formed by eutectic transformation. The results of the tensile strength of steels show that the strength of modified steels increased and then declined with the increase in the addition amount. When the addition amount was 0.16 wt.%, the modified steel obtained the maximum tensile strength of 759.0 MPa, which is an increase of 52% compared with to that with no addition. The hardness of the modified steel increased with the addition of (NbTi)C nanoparticles. The performance increase was mainly related to grain refinement and the particle strengthening of (NbTi)C nanoparticles, and the performance degradation was related to the increase in eutectic (NbTi)C.
A Second-Generation Voltage-Conveyor-Based Interface for Ultrasonic PVDF Sensors
Authors: Pullano Salvatore A. , Fiorillo Antonino S. , Barile Gianluca , Stornelli Vincenzo , Ferri Giuseppe
Published: January 2021

Exploiting the transmission and reception of low frequency ultrasounds in air is often associated with the innate echolocating abilities of some mammals, later emulated with sophisticated electronic systems, to obtain information about unstructured environments. Here, we present a novel approach for the reception of ultrasounds in air, which exploits a piezopolymer broadband sensor and an electronic interface based on a second-generation voltage conveyor (VCII). Taking advantage of its capability to manipulate both voltage and current signals, in this paper, we propose an extremely simple interface that presents a sensitivity level of about −100 dB, which is in line with commercially available references. The presented results are obtained without any filtration stage. The second-generation voltage conveyor active device is implemented through a commercially available AD844, with a supply voltage of ±15 V.
Bacillus thuringiensis Cells Selectively Captured by Phages and Identified by Surface Enhanced Raman Spectroscopy Technique
Authors: Almaviva Salvatore , Palucci Antonio , Aruffo Eleonora , Rufoloni Alessandro , Lai Antonia
Published: January 2021

In this work, the results on the detection and identification of Bacillus thuringiensis (Bt) cells by using surface-enhanced Raman spectroscopy (SERS) are presented. Bt has been chosen as a harmless surrogate of the pathogen Bacillus anthracis (Ba) responsible for the deadly Anthrax disease, because of their genetic similarities. Drops of 200 μL of Bt suspensions, with concentrations 102 CFU/mL, 104 CFU/mL, 106 CFU/mL, were deposited on a SERS chip and sampled after water evaporation. To minimize the contribution to the SERS data given by naturally occurring interferents present in a real scenario, the SERS chip was functionalized with specific phage receptors BtCS33, that bind Bt (or Ba) cells to the SERS surface and allow to rinse the chip removing unwanted contaminants. Different chemometric approaches were applied to the SERS data to classify spectra from Bt-contaminated and uncontaminated areas of the chip: Principal Component Regression (PCR), Partial Least Squares Regression (PLSR) and Data Driven Soft Independent Modeling of Class Analogy (DD-SIMCA). The first two was tested and trained by using data from both contaminated and un-contaminated chips, the last was trained by using data from un-contaminated chips only and tested with all the available data. All of them were able to correctly classify the SERS spectra with great accuracy, the last being suitable for an automated recognition procedure.
Taxonomic and Functional Diversity of Heterotrophic Protists (Cercozoa and Endomyxa) from Biological Soil Crusts
Authors: Khanipour Roshan Samira , Dumack Kenneth , Bonkowski Michael , Leinweber Peter , Karsten Ulf , Glaser Karin
Published: January 2021

Biological soil crusts (biocrusts) accommodate diverse communities of phototrophic and heterotrophic microorganisms. Heterotrophic protists have critical roles in the microbial food webs of soils, with Cercozoa and Endomyxa often being dominant groups. Still, the diversity, community composition, and functions of Cercozoa and Endomyxa in biocrusts have been little explored. In this study, using a high-throughput sequencing method with taxon-specific barcoded primers, we studied cercozoan and endomyxan communities in biocrusts from two unique habitats (subarctic grassland and temperate dunes). The communities differed strongly, with the grassland and dunes being dominated by Sarcomonadea (69%) and Thecofilosea (43%), respectively. Endomyxa and Phytomyxea were the minor components in dunes. Sandonidae, Allapsidae, and Rhogostomidae were the most abundant taxa in both habitats. In terms of functionality, up to 69% of the grassland community was constituted by bacterivorous Cercozoa. In contrast, cercozoan and endomyxan communities in dunes consisted of 31% bacterivores, 25% omnivores, and 20% eukaryvores. Facultative and obligate eukaryvores mostly belonged to the families Rhogostomidae, Fiscullidae, Euglyphidae, Leptophryidae, and Cercomonadidae, most of which are known to feed mainly on algae. Biocrust edaphic parameters such as pH, total organic carbon, nitrogen, and phosphorus did not have any significant influence on shaping cercozoan communities within each habitat, which confirms previous results from dunes.
Multicenter Evaluation of an ELISA for the Detection of Cryptosporidium spp. Antigen in Clinical Human Stool Samples
Authors: Razakandrainibe Romy , Mérat Célia , Kapel Nathalie , Sautour Marc , Guyot Karine , Gargala Gilles , Ballet Jean-Jacques , Le Pape Patrice ,   French Cryptosporidiosis Network, Dalle Frédéric , Favennec Loïc
Published: January 2021

Human cryptosporidiosis remains underdiagnosed, and rapid/accurate diagnosis is of clinical importance. Diagnosis of the Cryptosporidium oocyst in stool samples by conventional microscopy is labor-intensive, time-consuming, and requires skillful experience. Thus, we aimed to evaluate the usefulness of a coproantigen enzyme-linked immunosorbent assay (ELISA) test in detecting Cryptosporidium spp. from fecal specimens. For this aim, we evaluated the performances of a commercial ELISA (CoproELISA Cryptosporidium kit, Savyon Diagnostics, Israel) for the detection of Cryptosporidium spp. in random clinical stool samples through a multicenter study. The sensitivity and specificity for coproantigen ELISA were 98.86% and 94.32%, respectively. The coproantigen ELISA results indicate that the simple, rapid, reliable, and standardized immunoassay test is sensitive and specific for routine diagnosis, and may be useful for large-scale epidemiological studies of cryptosporidiosis.
Single Cell Analysis of Bistable Expression of Pathogenicity Island 1 and the Flagellar Regulon in Salmonella enterica
Authors: Sánchez-Romero María Antonia , Casadesús Josep
Published: January 2021

Bistable expression of the Salmonella enterica pathogenicity island 1 (SPI-1) and the flagellar network (Flag) has been described previously. In this study, simultaneous monitoring of OFF and ON states in SPI-1 and in the flagellar regulon reveals independent switching, with concomitant formation of four subpopulations: SPI-1OFF FlagOFF, SPI-1OFF FlagON, SPI-1ON FlagOFF, and SPI-1ON FlagON. Invasion assays upon cell sorting show that none of the four subpopulations is highly invasive, thus raising the possibility that FlagOFF cells might contribute to optimal invasion as previously proposed for SPI-1OFF cells. Time lapse microscopy observation indicates that expression of the flagellar regulon contributes to the growth impairment previously described in SPI-1ON cells. As a consequence, growth resumption in SPI-1ON FlagON cells requires switching to both SPI-1OFF and FlagOFF states.
Sr, S, and O Isotope Compositions of Evaporites in the Lanping–Simao Basin, China
Authors: Shen Lijian , Wang Licheng , Liu Chenglin , Zhao Yanjun
Published: January 2021

Evaporites are widely distributed within continental “red beds” in the Lanping–Simao Basin, west Yunnan, China. Sr (Strontium), S (Sulfur), and O (Oxygen) isotope compositions have been measured on 54 sulfate or/and sulfate-bearing samples collected from Lanping, Nuodeng, Jinggu, Mengyejing, Baozang throughout the Lanping–Simao Basin. The 87Sr/86Sr ratios of all samples (0.708081 to 0.710049) are higher than those of contemporaneous seawater, indicating a significant continental contribution to the drainage basin. Sulfates in the Lanping Basin have higher 87Sr/86Sr ratios (0.709406 to 0.710049) than those (0.708081 to 0.709548) in the Simao Basin. Nevertheless, the δ34S values of gypsums (13.4‰ to 17.6‰) in Lanping and Baozang fall within the range of Cretaceous seawater. Gypsums from a single section in Baozang have trends of decreasing δ34S values and increasing 87Sr/86Sr ratios from base to top, indicating continental input played an increasingly significant role with the evaporation of brines. High δ34S values (20.5‰ to 20.7‰) of celestites in Lanping are probably caused by bacterial sulfate reduction (BSR) process in which 34S were enriched in residual sulfates and/or recycling of Triassic evaporites. The reduced δ34S values of gypsums (9.5‰ to 10.4‰) in Nuodeng could have been caused by oxidation of sulfides weathered from Jinding Pb-Zn deposit. The complex O isotope compositions indicate that sulfates in the Lanping–Simao Basin had undergone sulfate reduction, re-oxidation, reservoir effects, etc. In conclusion, the formation of continental evaporites was likely derived from seawater due to marine transgression during the Cretaceous period. Meanwhile, non-marine inflows have contributed to the basin significantly.
Simultaneous Determination of Cortisol, Cortisone, and Multiple Illicit Drugs in Hair among Female Drug Addicts with LC-MS/MS
Authors: Duan Cailing , Wu Yan , Yang Jin , Chen Shenghuo , Pu Yun , Deng Huihua
Published: January 2021

Long-term dependence of illicit drugs impairs the function of the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the secretion of endogenous steroids, cortisol, and cortisone. Thus, the present study aimed to develop a sensitive method for simultaneous determination of the multiple illicit drugs and two steroids in hair to monitor the status of illicit drug exposure and the physiological and psychological health of drug addicts. The target analytes were extracted from hair by incubation with 1 mL methanol for 24 h at 40 °C and then determined with LC-APCI+-MS/MS. The validated method showed acceptable linearity (R2 > 0.99) in the range of 1.25–250 pg/mg for cortisol and cortisone, 2.5–125 pg/mg for heroin, 2.5–1250 pg/mg for ketamine, 2.5–5000 pg/mg for methamphetamine (MAM), 2.5–250 pg/mg for 3, 4-methylenedioxymethamphetamine (MDMA), morphine, and 6-monoacetylmorphine (6-AM). Limits of quantification were 1.6, 1.2, 1.6, 1.0, 1.4, 0.3, 2.1, and 1.2 pg/mg for cortisol, cortisone, heroin, ketamine, MAM, MDMA, morphine, and 6-AM, respectively. Method recoveries were from 90–115% for all analytes. Inter-day and intra-day coefficients of variation were within 10%. Finally, this method was successfully applied to detect the aforementioned analytes in hair among female drug addicts who self-reported to be MAM abuser, heroin abuser, ketamine abuser, and abuser of mixture drugs of MAM and heroin. MAM abusers with current MAM use showed significantly higher concentrations of cortisol, MAM, and MDMA than controls with drug withdrawal.
Orientation-Dependent Conversion of VLS-Grown Lead Iodide Nanowires into Organic-Inorganic Hybrid Perovskites
Authors: Shim Hyewon , Hwang Yunjeong , Kang Sung Gu , Shin Naechul
Published: January 2021

In this study, we demonstrate Sn-assisted vapor-liquid-solid (VLS) growth of lead iodide (PbI2) nanowires with van der Waals layered crystal structure and subsequent vapor-phase conversion into methylammonium lead iodide (CH3NH3PbI3) perovskites. Our systematic microscopic investigations confirmed that the VLS-grown PbI2 nanowires display two major growth orientations of [0001] and [1¯21¯0], corresponding to the stacking configurations of PbI2 layers to the nanowire axis (transverse for [0001] vs. parallel for [1¯21¯0]). The resulting difference in the sidewall morphologies was correlated with the perovskite conversion, where [0001] nanowires showed strong localized conversion at top and bottom, as opposed to [1¯21¯0] nanowires with an evenly distributed degree of conversion. An ab initio energy calculation suggests that CH3NH3I preferentially diffuses and intercalates into (112¯0) sidewall facets parallel to the [1¯21¯0] nanowire axis. Our results underscore the ability to control the crystal structures of van der Waals type PbI2 in nanowire via the VLS technique, which is critical for the subsequent conversion process into perovskite nanostructures and corresponding properties.
Fluorescence Signal Enhancement in Antibody Microarrays Using Lightguiding Nanowires
Authors: Verardo Damiano , Liljedahl Leena , Richter Corinna , Agnarsson Björn , Axelsson Ulrika , Prinz Christelle N. , Höök Fredrik , Borrebaeck Carl A. K. , Linke Heiner
Published: January 2021

Fluorescence-based detection assays play an essential role in the life sciences and medicine. To offer better detection sensitivity and lower limits of detection (LOD), there is a growing need for novel platforms with an improved readout capacity. In this context, substrates containing semiconductor nanowires may offer significant advantages, due to their proven light-emission enhancing, waveguiding properties, and increased surface area. To demonstrate and evaluate the potential of such nanowires in the context of diagnostic assays, we have in this work adopted a well-established single-chain fragment antibody-based assay, based on a protocol previously designed for biomarker detection using planar microarrays, to freestanding, SiO2-coated gallium phosphide nanowires. The assay was used for the detection of protein biomarkers in highly complex human serum at high dilution. The signal quality was quantified and compared with results obtained on conventional flat silicon and plastic substrates used in the established microarray applications. Our results show that using the nanowire-sensor platform in combination with conventional readout methods, improves the signal intensity, contrast, and signal-to-noise by more than one order of magnitude compared to flat surfaces. The results confirm the potential of lightguiding nanowires for signal enhancement and their capacity to improve the LOD of standard diagnostic assays.
Au/CdS Core-Shell Sensitized Actinomorphic Flower-Like ZnO Nanorods for Enhanced Photocatalytic Water Splitting Performance
Authors: Li Ying , Liu Tie , Feng Shuang , Yang Wenshu , Zhu Ying , Zhao Yingying , Liu Zhiyan , Yang Haibin , Fu Wuyou
Published: January 2021

Herein, a novel actinomorphic flower-like ZnO/Au/CdS nanorods ternary composite photocatalyst is prepared to extend the light-responsive range, reduce the photogenerated charge carriers recombination, and ultimately improve the water splitting performance. Flower-like ZnO nanorods are synthesized by a chemical bath method and the CdS nanoparticles are sensitized by successive ionic layer adsorption and reaction method. Then the Au nanoparticles as co-catalysts are introduced by the photodeposition method to modify the interface of ZnO/CdS for reducing the photogenerated electron recombination rate and further improving the performance of water splitting. Detailed characterizations and measurements are employed to analyse the crystallinity, morphology, composition, and optical properties of the flower-like ZnO/Au/CdS nanorods samples. As a result, the flower-like ZnO/Au/CdS nanorod samples present significantly enhanced water splitting performance with a high gas evolution rate of 502.2 μmol/g/h, which is about 22.5 and 1.5 times higher than that of the pure ZnO sample and ZnO/CdS sample. The results demonstrate that the flower-like ZnO/Au/CdS nanorods ternary composite materials have great application potential in photocatalytic water splitting for the hydrogen evolution field.
Stabilization of Calcium Oxalate Precursors during the Pre- and Post-Nucleation Stages with Poly(acrylic acid)
Authors: Díaz-Soler Felipe , Rodriguez-Navarro Carlos , Ruiz-Agudo Encarnación , Neira-Carrillo Andrónico
Published: January 2021

In this work, calcium oxalate (CaOx) precursors were stabilized by poly(acrylic acid) (PAA) as an additive under in vitro crystallization assays involving the formation of pre-nucleation clusters of CaOx via a non-classical crystallization (NCC) pathway. The in vitro crystallization of CaOx was carried out in the presence of 10, 50 and 100 mg/L PAA by using automatic calcium potentiometric titration experiments at a constant pH of 6.7 at 20 °C. The results confirmed the successful stabilization of amorphous calcium oxalate II and III (ACOII and ACO III) nanoparticles formed after PNC in the presence of PAA and suggest the participation and stabilization of polymer-induced liquid-precursor (PILP) in the presence of PAA. We demonstrated that PAA stabilizes CaOx precursors with size in the range of 20–400 nm. PAA additive plays a key role in the in vitro crystallization of CaOx stabilizing multi-ion complexes in the pre-nucleation stage, thereby delaying the nucleation of ACO nanoparticles. Indeed, PAA additive favors the formation of more hydrated and soluble phase of ACO nanoparticles that are bound by electrostatic interactions to carboxylic acid groups of PAA during the post-nucleation stage. These findings may help to a better understanding of the pathological mineralization resulting in urolithiasis in mammals.
Construction of Inorganic Bulks through Coalescence of Particle Precursors
Authors: Mu Zhao , Tang Ruikang , Liu Zhaoming
Published: January 2021

Bulk inorganic materials play important roles in human society, and their construction is commonly achieved by the coalescence of inorganic nano- or micro-sized particles. Understanding the coalescence process promotes the elimination of particle interfaces, leading to continuous bulk phases with improved functions. In this review, we mainly focus on the coalescence of ceramic and metal materials for bulk construction. The basic knowledge of coalescent mechanism on inorganic materials is briefly introduced. Then, the properties of the inorganic precursors, which determine the coalescent behaviors of inorganic phases, are discussed from the views of particle interface, size, crystallinity, and orientation. The relationships between fundamental discoveries and industrial applications are emphasized. Based upon the understandings, the applications of inorganic bulk materials produced by the coalescence of their particle precursors are further presented. In conclusion, the challenges of particle coalescence for bulk material construction are presented, and the connection between recent fundamental findings and industrial applications is highlighted, aiming to provide an insightful outlook for the future development of functional inorganic materials.
Reduction of the Diazo Functionality of α-Diazocarbonyl Compounds into a Methylene Group by NH3BH3 or NaBH4 Catalyzed by Au Nanoparticles
Authors: Kidonakis Marios , Stratakis Manolis
Published: January 2021

Supported Au nanoparticles on TiO2 (1 mol%) are capable of catalyzing the reduction of the carbene-like diazo functionality of α-diazocarbonyl compounds into a methylene group [C=(N2) → CH2] by NH3BH3 or NaBH4 in methanol as solvent. The Au-catalyzed reduction that occurs within a few minutes at room temperature formally requires one hydride equivalent (B-H) and one proton that originates from the protic solvent. This pathway is in contrast to the Pt/CeO2-catalyzed reaction of α-diazocarbonyl compounds with NH3BH3 in methanol, which leads to the corresponding hydrazones instead. Under our stoichiometric Au-catalyzed reaction conditions, the ketone-type carbonyls remain intact, which is in contrast to the uncatalyzed conditions where they are selectively reduced by the boron hydride reagent. It is proposed that the transformation occurs via the formation of chemisorbed carbenes on Au nanoparticles, having proximally activated the boron hydride reagent. This protocol is the first general example of catalytic transfer hydrogenation of the carbene-like α -ketodiazo functionality.
Electrochemical Sensors Based on Conducting Polymers for the Aqueous Detection of Biologically Relevant Molecules
Authors: Terán-Alcocer Álvaro , Bravo-Plascencia Francisco , Cevallos-Morillo Carlos , Palma-Cando Alex
Published: January 2021

Electrochemical sensors appear as low-cost, rapid, easy to use, and in situ devices for determination of diverse analytes in a liquid solution. In that context, conducting polymers are much-explored sensor building materials because of their semiconductivity, structural versatility, multiple synthetic pathways, and stability in environmental conditions. In this state-of-the-art review, synthetic processes, morphological characterization, and nanostructure formation are analyzed for relevant literature about electrochemical sensors based on conducting polymers for the determination of molecules that (i) have a fundamental role in the human body function regulation, and (ii) are considered as water emergent pollutants. Special focus is put on the different types of micro- and nanostructures generated for the polymer itself or the combination with different materials in a composite, and how the rough morphology of the conducting polymers based electrochemical sensors affect their limit of detection. Polypyrroles, polyanilines, and polythiophenes appear as the most recurrent conducting polymers for the construction of electrochemical sensors. These conducting polymers are usually built starting from bifunctional precursor monomers resulting in linear and branched polymer structures; however, opportunities for sensitivity enhancement in electrochemical sensors have been recently reported by using conjugated microporous polymers synthesized from multifunctional monomers.
TiO2 Nanowires with Doped g-C3N4 Nanoparticles for Enhanced H2 Production and Photodegradation of Pollutants
Authors: Jiang Liushan , Zeng Fanshan , Zhong Rong , Xie Yu , Wang Jianli , Ye Hao , Ling Yun , Guo Ruobin , Zhao Jinsheng , Li Shiqian , Hu Yuying
Published: January 2021

With the rapid consumption of fossil fuels, along with the ever-increasing environmental pollution, it is becoming a top priority to explore efficient photocatalysts for the production of renewable hydrogen and degradation of pollutants. Here, we fabricated a composite of g-C3N4/TiO2 via an in situ growth method under the conditions of high-temperature calcination. In this method, TiO2 nanowires with a large specific surface area could provide enough space for loading more g-C3N4 nanoparticles to obtain C3N4/TiO2 composites. Of note, the g-C3N4/TiO2 composite could effectively photocatalyze both the degradation of several pollutants and production of hydrogen, both of which are essential for environmental governance. Combining multiple characterizations and experiments, we found that the heterojunction constructed by the TiO2 and g-C3N4 could increase the photocatalytic ability of materials by prompting the separation of photogenerated carriers. Furthermore, the photocatalytic mechanism of the g-C3N4/TiO2 composite was also clarified in detail.
Antimicrobial Activity of Zinc Oxide Nano/Microparticles and Their Combinations against Pathogenic Microorganisms for Biomedical Applications: From Physicochemical Characteristics to Pharmacological Aspects
Authors: Jin Su-Eon , Jin Hyo-Eon
Published: January 2021

Zinc oxide (ZnO) nano/microparticles (NPs/MPs) have been studied as antibiotics to enhance antimicrobial activity against pathogenic bacteria and viruses with or without antibiotic resistance. They have unique physicochemical characteristics that can affect biological and toxicological responses in microorganisms. Metal ion release, particle adsorption, and reactive oxygen species generation are the main mechanisms underlying their antimicrobial action. In this review, we describe the physicochemical characteristics of ZnO NPs/MPs related to biological and toxicological effects and discuss the recent findings of the antimicrobial activity of ZnO NPs/MPs and their combinations with other materials against pathogenic microorganisms. Current biomedical applications of ZnO NPs/MPs and combinations with other materials are also presented. This review will provide the better understanding of ZnO NPs/MPs as antibiotic alternatives and aid in further development of antibiotic agents for industrial and clinical applications.
Nanoscale Soft Wetting Observed in Co/Sapphire during Pulsed Laser Irradiation
Authors: Choi Jung Won , Ham Daseul , Han Seonghyun , Noh Do Young , Kang Hyon Chol
Published: January 2021

Liquid drops on deformable soft substrates exhibit quite complicated wetting behavior as compared to those on rigid solid substrates. We report on a soft wetting behavior of Co nanoparticles (NPs) on a sapphire substrate during pulsed laser-induced dewetting (PLID). Co NPs produced by PLID wetted the sapphire substrate with a contact angle near 70°, which is in contrast to typical dewetting behavior of metal thin films exhibiting contact angles greater than 90°. In addition, a nanoscale γ-Al2O3 wetting ridge about 15 nm in size and a thin amorphous Al2O3 interlayer were observed around and beneath the Co NP, respectively. The observed soft wetting behavior strongly indicates that the sapphire substrate became soft and deformable during PLID. Moreover, the soft wetting was augmented under PLID in air due to the formation of a CoO shell, resulting in a smaller contact angle near 30°.