Diffusion Screening Research Articles

Magnetic coupling through flux branching of adjacent type-I and -II superconductors in a neutron star

Abstract The inner and outer cores of neutron stars are believed to contain type-I and -II proton superconductors, respectively. The type-I superconductor exists in an intermediate state, comprising macroscopic flux-free and flux-containing regions, while the type-II superconductor is flux-free, except for microscopic, quantized flux tubes. Here, we show that the inner and outer cores are coupled magnetically, when the macroscopic flux tubes subdivide dendritically into quantized flux tubes, a phenomenon called flux branching. An important implication is that up to ∼1012(r1/106 cm) erg of energy are required to separate a quantized flux tube from its progenitor macroscopic flux tube, where r1 is the length of the macroscopic flux tube. Approximating the normal-superconducting boundary as sharp, we calculate the magnetic coupling energy between a quantized and macroscopic flux tube due to flux branching as a function of, f1, the radius of the type-I inner core divided by the radius of the type-II outer core. Strong coupling delays magnetic field decay in the type-II superconductor. For an idealised inner core containing only a type-I proton superconductor and poloidal flux, and in the absence of ambipolar diffusion and diamagnetic screening, the low magnetic moments (≲ 1027 G cm3) of recycled pulsars imply f1 ≲ 10−1.5.

Therapeutic potential activity of quercetin complexes against Streptococcus pneumoniae

This study investigates quercetin complexes as potential synergistic agents against the important respiratory pathogen Streptococcus pneumoniae. Six quercetin complexes (QCX1–6) were synthesized by reacting quercetin with various metal salts and boronic acids and characterized using FTIR spectroscopy. Their antibacterial activity alone and in synergism with antibiotics was evaluated against S. pneumoniae ATCC 49619 using disc diffusion screening, broth microdilution MIC determination, and checkerboard assays. Complexes QCX-3 and QCX-4 demonstrated synergy when combined with levofloxacin via fractional inhibitory concentration indices ≤ 0.5 as confirmed by time-kill kinetics. Molecular docking elucidated interactions of these combinations with virulence enzymes sortase A and sialidase. A biofilm inhibition assay found the synergistic combinations more potently reduced biofilm formation versus monotherapy. Additionally, gene–gene interaction networks, biological activity predictions and in-silico toxicity profiling provided insights into potential mechanisms of action and safety.

Antimicrobial secondary metabolites and antioxidant activities of fungal endophytes associated with Ziziphus spina-christi (L.) Desf. (Nabq) leaves

A total of 20 endophytic fungi were isolated (ZSEFL1-ZSEFL20) from Ziziphus spina-christi (L.) Desf. (Nabq) leaves. Four isolates A2/ZSEFL2, Alternaria alternata, D/ZSEFL14, Aspergillus niger, E/ZSEFL15, Epicoccum nigrum, and S/ZSEFL19, Penicillium crustosum were found to show the most promising antimicrobial activities either in plug or disc diffusion screening assays against Gram-positive, Gram-negative bacteria and pathogenic fungi. Antimicrobial activity was tested against Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, Serratia marcescens ATCC 14764, Klebsiella pneumoniae ATCC 700603, Candida albicans ATCC 10231, and Fusarium oxysporum ATCC417. In vitro antioxidant activity assay was conducted using the ABTS [2,2′-Azino-bis (3-Ethylbenzthiazoline-6-Sulfonic Acid)] free radical scavenging method. EtOAc extracts of all isolated endophytic fungi showed antioxidant activities. This study would be one of the first reports to measure the antioxidant activity of Z. spina-christi (L.) Desf. endophytic fungi. Therefore, these isolated endophytic fungi can provide additional information for medicinal sources of natural antioxidants and antimicrobial agents.

Commercial Versus Natural Activated Carbon Fabricated Sheets: Applied to Dyes Removal Application

AbstractIndustrial dyes are considered one of the main causes of increased water pollution of water. Many businesses, such as steel and paper, are located along riverbanks because they require large amounts of water in their manufacturing processes, and their wastes, which contain acids, alkalis, dyes, and other chemicals, are dumped and poured into rivers as effluents. For example, chemical enterprises producing aluminum emit a significant quantity of fluoride into the air and effluents into water bodies. Fertilizer facilities produce a lot of ammonia, whereas steel plants produce cyanide. Many nations consider employing wastewater treatment plants using physical, biological, and chemical methods to clean the wastewater to address environmental crises. The treated water can be used for targeting the irrigation systems in its majority, as it is biologically acceptable for that specific use, industrial dyes are considered one of the leading causes of increased water pollution of water. Many businesses, such as steel and paper, are located along riverbanks because they require large amounts of water in their manufacturing processes, and their wastes, which contain acids, alkalis, dyes, and other chemicals, are dumped and poured into rivers as effluents. For example, chemical enterprises producing aluminum emit a significant quantity of fluoride into the air and effluents into water bodies. Fertilizer facilities produce much ammonia, whereas steel plants produce cyanide. Chromium salts are used in. Many nations consider employing wastewater treatment plants using physical, biological, and chemical methods to clean the wastewater to address environmental crises. The treated water can target the majority of irrigation systems, as it is biologically acceptable for that specific use, which economizes the use of freshwater sources for municipal use. This study presents a novel method for fabricating an efficient adsorbent sheet for wastewater treatment. The sheets are fabricated by combining sugarcane bagasse pulp as a scaffold with commercial, naturally activated carbon, and bimetallic‐prepared adsorbents. Sugarcane bagasse is utilized in producing activated carbon because of its high carbon contents, availability, and low cost. The prepared composite sheets are synthesized and investigated for pollutants removal of crystal violet (CV), methyl orange (MO), and Chromium (CI) dyes. Different weight ratios of activated carbon are used to form a bio‐composite mixed sheet. The formed sheets’ morphology is performed via a high scanning electron microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). To determine the adsorption mechanism, the intra‐particle diffuse screening experiment is used to test the experimental data. All the prepared sheets can retain the pollutants, with the best removal efficiency of 98% for methyl orange adsorption onto the bio‐composite mixed sheet. The results of the parameter (time, concentration, and dose) sets provided valuable proof that the adsorption of methyl orange onto the bio‐composite sheet mixed with naturally activated carbon is an endothermic phenomenon involving physical adsorption.

Spatial Nonlinear Conversion of Structured Light for Machine Learning Based Ultra‐Accurate Information Networks

AbstractStructured light can be encoded to carry information for free‐space optical communications with an extended degree of freedom to increase the capacity, however, the accuracy issue along with capacity increase is one of the biggest challenges that prevent practical applications. To achieve high accuracy with high capacity by a simple method, they propose the spatial nonlinear conversion of structured light into a communication network, especially, realizing an ultra‐high‐accuracy point‐to‐multipoint (PtoMP) information transmission link. A series of coherently superposed spatial modes and their spatial nonlinear conversion states are used as information carriers to replace the prior orbital angular momentum beams and greatly expand channel capacity within quite low spatial mode order. Through the spatial nonlinear conversion of simple dual‐mode superposition and a very basic neural network for machine learning‐based recognition, as high as 99.5% accuracy for more than 500 modes is obtained. By a combination of diffuse reflection screens and multiple CCDs, the large observation angle PtoMP information transmission is also proved to be feasible. This work paves the way for practical large‐scale multi‐party information networks using structured light.

Methicillin, β-lactams, and Clindamycin Resistance Profiles of Staphylococcus aureus Strains Isolated from Patients with UTI in Bechar Province (Algeria)

Introduction: Staphylococcus aureus is a bacterial pathogen responsible for many dis-eases. Multidrug resistance in S aureus has become common worldwide and is a serious clinical issue in the treatment and care of S. aureus-infected patients. S. aureus uropathogenic strains isolated from patients with UTI in Bechar province (Algeria) were phenotypically identified and evaluated for multiple drug resistance (MDR) patterns against recommended antimicrobial drugs. Methods: Through selective media, the uropathogenic S. aureus strains were isolated by analyzing a total of 211 urine samples, then subjected to various biochemical identification tests. Multidrug resistance pattern (MRSA, MLSB, and β-lactamase production) among Staphylococcus aureus uropathogenic strains was performed using phenotypic tests. : A total of 50 S. aureus strains were isolated, i.e., 40,48% of all the isolated uropathogenic agents estimated at 126 isolates. More than 69% of the women had a urinary tract infection, i.e., a sex ratio (SR) of 0,43. The susceptibility test results showed that the isolated S. aureus strains were resistant to various antibiotics of the β-lactams class (penicillin, cefoxitin, and oxacillin) and were susceptible to gentamicin, chloramphenicol, co-trimoxazole, vancomycin, ofloxacin, and ciprofloxacin. Cefoxitin disk diffusion and agar screening tests showed that all the isolated S. aureus strains were qualified as MRSA at the rate of 100% (50/50), whereas a rate of 74% (37/50) was granted to MRSA using oxacillin disk diffusion test. The highest percentage of MDR-MRSA was observed in class three of antibiotics 12 (24%). The lowest percentage was observed in classes 8 and 9 of antibiotics 1 (2%). For MDR-MRSA, the MAR index ranged from 0,27 to 1,0. Results:: Penicillin disk diffusion (DD) and DDST (PI/PIT) tests showed a production rate of β-lactamase in the range of 94% and 80%, respectively. 85,1% (40/50) of penicillin-resistant strains were positive for DDST. Thus, the D-test among MRSA strains shows a rate of 38% (19/50) of cMLSB and no strain attributed to the iMLSB phenotype. Conclusion: This is an alarming rate, confirming the concern that is still being discussed within the medical teams of the national health sector as well as the Algerian antimicrobial resistance network, which requires prompt intervention to update a new strategy to fight antimicrobial re-sistance.

Bioactivity of crude extract produced by endophytic fungi isolated from Ziziphus spina-christi (Nabq) leaves for antimicrobial evaluation as well as optimization of culture medium conditions

Twenty fungal endophytes were isolated from Nabq, and plug diffusion screening revealed four of those isolates to be promising. These isolates were identified molecularly as Aspergillus sp. of Sect. Flavi (ZSEFL2) and Sec. Niger (ZSEFL14), and Penicillium spp. closest related to Penicillum crustosum (ZSEFL15, 19). Investigations were conducted to determine the effects of culture parameters, such as the type of culture medium, incubation temperature, initial pH and agitation, on the production of antimicrobial metabolites in a culture filtrate extract. Using the disk diffusion technique, antimicrobial metabolite synthesis was evaluated. In comparison to the other three distinct culture media (PDB-y, rice, and Cz), PDB demonstrated to be the best culture medium for the four tested fungal endophytes, exhibiting high levels of the Antimicrobial Index (AI). Also, a restricted range of incubation temperatures resulted in the formation of bioactive metabolites, but raising the incubation temperatures from 25 to 30 °C increased the amount of bioactive metabolites produced. Moreover, the best initial hydrogen concentration typically ranged from pH 5 to 6. Finally, when the conditions changed from stationary to shaking, the bioactive secondary metabolite's antimicrobial efficacy reduced. The behavior of the four examined fungal isolates was consistent, and they all required the same conditions to produce the most bioactive metabolites. Moreover, ethyl acetate extract's MIC values against the investigated bacterial and fungal human pathogens ranged from 0.19 to 6.25 mg/mL.

Anti-fungal bioactive terpenoids in the bioenergy crop switchgrass (Panicum virgatum) may contribute to ecotype-specific microbiome composition

Plant derived bioactive small molecules have attracted attention of scientists across fundamental and applied scientific disciplines. We seek to understand the influence of these phytochemicals on rhizosphere and root-associated fungi. We hypothesize that – consistent with accumulating evidence that switchgrass genotype impacts microbiome assembly – differential terpenoid accumulation contributes to switchgrass ecotype-specific microbiome composition. An initial in vitro Petri plate-based disc diffusion screen of 18 switchgrass root derived fungal isolates revealed differential responses to upland- and lowland-isolated metabolites. To identify specific fungal growth-modulating metabolites, we tested fractions from root extracts on three ecologically important fungal isolates – Linnemania elongata, Trichoderma sp. and Fusarium sp. Saponins and diterpenoids were identified as the most prominent antifungal metabolites. Finally, analysis of liquid chromatography-purified terpenoids revealed fungal inhibition structure – activity relationships (SAR). Saponin antifungal activity was primarily determined by the number of sugar moieties – saponins glycosylated at a single core position were inhibitory whereas saponins glycosylated at two core positions were inactive. Saponin core hydroxylation and acetylation were also associated with reduced activity. Diterpenoid activity required the presence of an intact furan ring for strong fungal growth inhibition. These results inform future breeding and biotechnology strategies for crop protection with reduced pesticide application.

Diatom-Based Nanomedicine for Colorectal Cancer Treatment: New Approaches for Old Challenges.

Colorectal cancer is among the most prevalent and lethal cancers globally. To address this emergency, countries have developed diffuse screening programs and innovative surgical techniques with a consequent decrease in mortality rates in non-metastatic patients. However, five years after diagnosis, metastatic CRC is still characterized by less than 20% survival. Most patients with metastatic CRC cannot be surgically treated. For them, the only option is treatment with conventional chemotherapies, which cause harmful side effects in normal tissues. In this context, nanomedicine can help traditional medicine overcome its limits. Diatomite nanoparticles (DNPs) are innovative nano-based drug delivery systems derived from the powder of diatom shells. Diatomite is a porous biosilica largely found in many areas of the world and approved by the Food and Drug Administration (FDA) for pharmaceutical and animal feed formulations. Diatomite nanoparticles with a size between 300 and 400 nm were shown to be biocompatible nanocarriers capable of delivering chemotherapeutic agents against specific targets while reducing off-target effects. This review discusses the treatment of colorectal cancer with conventional methods, highlighting the drawbacks of standard medicine and exploring innovative options based on the use of diatomite-based drug delivery systems. Three targeted treatments are considered: anti-angiogenetic drugs, antimetastatic drugs, and immune checkpoint inhibitors.

Teicoplanin-Resistant Coagulase-Negative Staphylococci: Do the Current Susceptibility Testing Methods Reliably Detect This Elusive Phenotype?

Coagulase-negative staphylococci (CoNS), members of the skin commensal microbiota, are increasingly associated with local or systemic infections due to a shift in patient populations in recent decades. Subsequently, more CoNS strains have been subjected to antibiotic susceptibility testing (AST), thus leading to the increased detection of teicoplanin resistance. However, data concerning teicoplanin resistance among CoNS strains remain limited, heterogeneous, and inconclusive. We collected 162 consecutive CoNS strains identified using Vitek-2 as teicoplanin-resistant and tested them with a range of AST methods. The results of standard and high inoculum broth microdilution (sBMD; hBMD), agar dilution (AD) after 24 h and 48 h incubation, standard and macrogradient diffusion strip (sGDT, MET), screening agar, and disc diffusion were compared to assess their robustness and to establish a diagnostic algorithm to detect teicoplanin resistance. sBMD was used as the reference method, and the lowest number of strains were teicoplanin-resistant using this method. sGDT and disc diffusion generated similar results to sBMD. Compared with sBMD, AD-24 h generated the lowest number of false teicoplanin-resistant strains, followed by hBMD, AD-48 h, and Vitek-2. sGDT, a fast, easy, affordable method in diagnostic settings, generated the highest rate of false teicoplanin-susceptible strains. Vitek-2 testing produced the highest number of teicoplanin-resistant strains. Only in two strains was the initial Vitek-2 teicoplanin resistance confirmed using five other AST methods. In conclusion, the different antibiotic susceptibility testing methods generated inconsistent, inconclusive, and discrepant results, thus making it difficult to establish a diagnostic algorithm for suspected teicoplanin resistance. Teicoplanin testing proved to be challenging and easily influenced by technical factors. This study aimed not only to raise awareness of teicoplanin resistance testing but also of the need for future studies focusing on the clinical efficacy of teicoplanin in relation to its susceptibility results.

Curved Computer-Generated Integral Imaging Based on Backward Ray-Tracing Technique

In traditional computer-generated integral imaging (CGII) methods, the generated elemental image array (EIA) is flat, and it doesn't fit for curved integral imaging (II) systems. Here, a curved CGII method was proposed for curved II system. In the proposed method, multiple virtual camera arrays (VCAs) were built up to determine the origins and directions of the traced rays. Combined with the backward ray-tracing (BRT) technique, a curved EIA was generated, and the rendering time was the same as the BRT-CGII of flat II system. A curved II system consisting of a curved organic light emitting diode display screen, a curved lens array and a curved optical diffuser screen was built up in the experiment. The proposed curved CGII method generated correct curved EIA for the curved II system, and the system presented vivid 3D images with the viewing angle as wide as 80° × 50°.

Evaluation of Cefoxitin Disc Diffusion and Chromogenic Agar in the Detection of Methicillin Resistant Staphylococcus aureus

Methicillin resistant Staphylococcus aureus (MRSA) has a worldwide distribution and is an important cause of clinical and epidemiological problems. The aim of this study was to evaluate the usefulness of some phenotypic methods for the detection of methicillin resistant S. aureus in clinical laboratories. The study is cross sectional. A total of 93 S. aureus isolates were tested using cefoxitin disk diffusion (CDD) and oxacillin resistance screening agar base (ORSAB) with reference to mecA gene PCR. Of the 93 isolates, CDD test showed 34 were MRSA, while ORSAB recorded 42. MecA gene was detected by PCR in 34 of the isolates. The CDD showed 97.1% sensitivity and 98.3% specificity and therefore superior to ORSAB with sensitivity 97.1% and specificity 84.7%. The cefoxitin disk test required no special test conditions and can improve the reliability of routine tests for the detection of MRSA. CDD test can thus be used as a cheap and reliable alternative to PCR for the detection of MRSA in resources limited settings.

Antibacterial Effect of 16 Essential Oils and Modulation of mex Efflux Pumps Gene Expression on Multidrug-Resistant Pseudomonas aeruginosa Clinical Isolates: Is Cinnamon a Good Fighter?

The purpose of the study was to describe the antimicrobial activity of 16 common essential oils (EOs) on multidrug-resistant (MDR) Pseudomonas aeruginosa clinical isolates, including the determination of the effects on mex efflux pumps gene expression. Seventy-two clinical isolates of P. aeruginosa collected between 2020-2022 were screened for susceptibility to EOs using Kirby-Bauer disk diffusion to identify potential candidates for future alternative therapies. The minimal inhibitory concentration (MIC) was further determined for the EO that proved antibacterial activity following the disk diffusion screening. Positive and negative controls were also used for method validation. Since cinnamon EO exhibited the best antimicrobial activity, it was further used to evaluate its influence on mex A, B, C, E, and X efflux pumps gene expression using real-time RT-PCR. Cinnamon EO inhibited all P. aeruginosa strains, followed by thyme EO (37.5%, n = 27) and lavender EO (12.5%, n = 9). The other EOs were less efficient. The MIC detection showed that cinnamon at a concentration of 0.05% v/v inhibited all MDR P. aeruginosa isolates. Thyme, turmeric, peppermint, basil, clove, and lavender EOs presented various results, most of them having activity at concentrations higher than 12.5% v/v. By studying the activity of cinnamon EO on mex efflux pumps, it was found that mexA and mexB (66.5%) were generally under-expressed. The remarkable results produced using the very low concentrations of cinnamon EO, with 100% antimicrobial activity against multi-, extended-, and pan- drug-resistant (MDR, XDR, PDR) P. aeruginosa clinical isolates, completed with the severe alteration of the RNA messaging system, supports its potential to be used as adjuvant treatment, with impact on therapeutic results.

Integral imaging-based tabletop light field 3D display with large viewing angle

Light field 3D display technology is considered a revolutionary technology to address the critical visual fatigue issues in the existing 3D displays. Tabletop light field 3D display provides a brand-new display form that satisfies multi-user shared viewing and collaborative works, and it is poised to become a potential alternative to the traditional wall and portable display forms. However, a large radial viewing angle and correct radial perspective and parallax are still out of reach for most current tabletop light field 3D displays due to the limited amount of spatial information. To address the viewing angle and perspective issues, a novel integral imaging-based tabletop light field 3D display with a simple flat-panel structure is proposed and developed by applying a compound lens array, two spliced 8K liquid crystal display panels, and a light shaping diffuser screen. The compound lens array is designed to be composed of multiple three-piece compound lens units by employing a reverse design scheme, which greatly extends the radial viewing angle in the case of a limited amount of spatial information and balances other important 3D display parameters. The proposed display has a radial viewing angle of 68.7° in a large display size of 43.5 inches, which is larger than the conventional tabletop light field 3D displays. The radial perspective and parallax are correct, and high-resolution 3D images can be reproduced in large radial viewing positions. We envision that this proposed display opens up possibility for redefining the display forms of consumer electronics.

Multifunctional Medical Grade Resin with Enhanced Mechanical and Antibacterial Properties: The Effect of Copper Nano-Inclusions in Vat Polymerization (VPP) Additive Manufacturing.

Vat photopolymerization (VPP) is an additive manufacturing process commonly used in medical applications. This work aims, for the first time in the literature, to extend and enhance the performance of a commercial medical-grade resin for the VPP process, with the development of nanocomposites, using Copper (Cu) nanoparticles as the additive at two different concentrations. The addition of the Cu nanoparticles was expected to enhance the mechanical properties of the resin and to enable biocidal properties on the nanocomposites since Cu is known for its antibacterial performance. The effect of the Cu concentration was investigated. The nanocomposites were prepared with high-shear stirring. Specimens were 3D printed following international standards for mechanical testing. Their thermal and spectroscopic response was also investigated. The morphological characteristics were examined. The antibacterial performance was evaluated with an agar well diffusion screening process. The experimental results were analyzed with statistical modeling tools with two control parameters (three levels each) and eleven response parameters. Cu enhanced the mechanical properties in all cases studied. 0.5 wt.% Cu nanocomposite showed the highest improvement (approximately 11% in tensile and 10% in flexural strength). The antibacterial performance was sufficient against S. aureus and marginal against E. coli.

Trilateral Multi-Functional Polyamide 12 Nanocomposites with Binary Inclusions for Medical Grade Material Extrusion 3D Printing: The Effect of Titanium Nitride in Mechanical Reinforcement and Copper/Cuprous Oxide as Antibacterial Agents.

In this work, for the first time, polyamide 12 (PA12) nanocomposites with binary inclusions in material extrusion (MEX) 3D printing were developed. The aim was to achieve an enhanced mechanical response with the addition of titanium nitride (TiN) and antibacterial performance with the addition of copper (Cu) or cuprous oxide (Cu2O), towards the development of multi-functional nanocomposite materials, exploiting the 3D printing process benefits. The prepared nanocomposites were fully characterized for their mechanical properties. The thermal properties were also investigated. Morphological characterization was performed with atomic force microscopy (AFM) and scanning electron microscopy (SEM). The antibacterial performance was investigated with an agar-well diffusion screening process. Overall, the introduction of these nanofillers induced antibacterial performance in the PA12 matrix materials, while at the same time, the mechanical performance was significantly increased. The results of the study show high potential for expanding the areas in which 3D printing can be used.

Bacillus velezensis suppression on the growth of Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease in marine shrimp

ABSTRACT This study evaluated the inhibitory function of probiotics isolated from three commercial products used in shrimp farming management. Five species of probiotics were isolated from the commercial products, which were B. subtilis, B. megaterium, B. velezensis, B. licheniformis, and B. amyloliquefaciens. The inhibitory function of the isolated probiotics on the growth of an acute hepatopancreatic necrosis disease (AHPND)-causing V. parahaemolyticus (VPAHPND), nonpathogenic V. parahaemolyticus, and Vibrio spp. isolated from shrimp farming samples were examined by disc diffusion and bacteriocin-like inhibitory substance test. Disc diffusion and bacteriocin-like inhibitory substance screening indicated that only B. velezensis could inhibit all Vibrio spp. Inhibitory efficiency of B. velezensis was further evaluated in the liquid media using the co-culture technique. With the assistance of a growth curve-monitoring system, we could examine multiple co-culture factors that affected the probiotic efficiency in the same experiment. The results demonstrated that the inhibitory efficiency of B. velezensis was increased with its concentration. The inhibitory efficiency of B. velezensis incubating in tryptic soy broth at pH 7.4 with 2% NaCl (TSB+) and Luria-Bertani broth at pH 7.4 with 1% NaCl (LB) was better than in alkaline peptone water broth at pH 8 with 2% NaCl (APW).

Multi-functional polyamide 12 (PA12)/ multiwall carbon nanotube 3D printed nanocomposites with enhanced mechanical and electrical properties

ABSTRACT Inducing electrical properties in thermoplastic materials and enhancing their mechanical properties with the addition of nanofiller in Fused Filament Fabrication (FFF) is the main purpose of the study. Multiwall carbon nanotubes (MWCNT) at different weight percentage (wt.%) loadings (0.1%, 0.5%, 1.0%, 2.5%, 5.0%, 10.0%) were incorporated into the Polyamide 12 (PA12) matrix. Melt mixing followed by filament extrusion was applied. Filaments were employed to 3D print specimens. A thorough study on the electrically Conductive Polymeric Composites (CPCs) electrical percolation threshold was carried out. Mechanical and thermomechanical response investigations were also conducted. Scanning Electron Microscopy (SEM) was employed to study the morphology of the 3D printed samples. The results showed a mechanical and thermomechanical properties enhancement for 5.0 wt.% filler’s ratio. The electrical conductivity increased by increasing the filler loading. The 10% wt.% PA12/MWCNT nanocomposite additionally exhibited an electrothermal Joule-heating behavior. The antibacterial behavior was also tested with the agar well diffusion screening method, for gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus). A mild antimicrobial performance was observed. It can be concluded that the multi-functional PA12/MWCNT 3D printed lightweight CPCs developed herein could be applied in various applications, e.g. joule-heating devices, flexible conductors, and anti-static enclosures.

Methodology Of Imaging Photometric Device Using In Museum

A method of using a digital imaging luminance meters (ILMD) for noncontact measurement of the illumination distribution over the surface of paintings is proposed. These measurements require a digital imaging luminance meters, an auxiliary diffuse reflection screen, and a ILMD software. The estimation of uncertainty of proposed method is fulfilled.

Medical-Grade Polyamide 12 Nanocomposite Materials for Enhanced Mechanical and Antibacterial Performance in 3D Printing Applications.

During the COVID-19 pandemic, wide use of 3D printing technologies has been enabled. Fused filament fabrication (FFF) is the most widely used technique in 3D printing communities worldwide for the fabrication of medical components such as face shields and respiratory valves. In the current study, the potential of Polyamide 12 (PA12) silver-doped antibacterial nanopowder (AgDANP) nanocomposites is evaluated for everyday FFF usage. Filling loadings of 1.0-2.0-3.0 and 4.0 wt.% were selected for nanocomposite preparation. Mechanical performance analysis was conducted on the basis of tensile, flexural, impact, and Vickers microhardness measurements in FFF 3D-printed specimens. Scanning Electron Microscopy (SEM) images were used for morphology and processing evaluation, as well as thermal performance measurements, conducted by Thermogravimetric Analysis (TGA) tests. Finally, the antibacterial performance was tested using the agar-well diffusion screening method, and the shape effect of the specimens was also investigated. The addition of 2.0 wt.% AgDANPs resulted in an enhancement of approximately 27% for both tensile and flexural stresses, while the antibacterial performance was sufficiently high among the nanocomposites tested. The shape effect exhibited the potential for antibacterial performance at low filling ratios, while the effect was diminished with increasing filler of AgDANPs.