Hasil untuk "Microscopy"

P. Bindu, Sabu Thomas

ZnO nanoparticles were synthesized from chitosan and zinc chloride by a precipitation method. The synthesized ZnO nanoparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction peak profile analysis, Scanning electron microscopy, Transmission electron microscopy and Photoluminescence. The X-ray diffraction results revealed that the sample was crystalline with a hexagonal wurtzite phase. We have investigated the crystallite development in ZnO nanoparticles by X-ray peak profile analysis. The Williamson–Hall analysis and size–strain plot were used to study the individual contributions of crystallite sizes and lattice strain ϵ on the peak broadening of ZnO nanoparticles. The parameters including strain, stress and energy density value were calculated for all the reflection peaks of X-ray diffraction corresponding to wurtzite hexagonal phase of ZnO lying in the range 20°–80° using the modified form of Williamson–Hall plots and size–strain plot. The results showed that the crystallite size estimated from Scherrer’s formula, Williamson–Hall plots and size–strain plot, and the particle size estimated from Transmission electron microscopy analysis are very much inter-correlated. Both methods, the X-ray diffraction and Transmission electron microscopy, provide less deviation between crystallite size and particle size in the present case.

D. Paganin, S. Mayo, T. Gureyev et al.

R. Amann, L. Krumholz, D. A. Stahl

Eyram Kuma Hanu, Felix Dolla Dimado, Benjamin Tetteh Hansen et al.

Abstract Background Scabies is an underreported neglected tropical disease in Ghana, with outbreaks often occurring in rural communities where overcrowding and limited access to primary care facilitate transmission. On 19 May 2025, a suspected cluster of pruritic skin lesions was reported from Tapa Appiakrom, a farming village in Biakoye District. We conducted an investigation to confirm the outbreak, determine its magnitude, and implement control measures. Methods A descriptive epidemiological investigation was conducted from 20 to 24 May 2025. Active case finding was performed through house-to-house visits, clinical examinations, and interviews. Suspected, probable, and confirmed case definitions were applied. Skin scraping was performed for the index case and examined by microscopy. Data were analysed by person, place, and time. Control measures included ivermectin administration for cases and contacts and community sensitization. Results Nine cases were identified across three compounds (attack rate: 15.0% among examined residents [9/60] and 3.0% of the estimated village population [9/300]). The epidemic curve showed a propagated pattern of transmission consistent with person-to-person spread within households. Following ivermectin administration and brief health education delivered to approximately 60 residents, no new cases were detected two weeks after the intervention. Conclusion A scabies outbreak affecting nine individuals was confirmed in Tapa Appiakrom. Early event-based reporting by a community volunteer facilitated rapid detection. Prompt ivermectin treatment and community sensitization successfully contained the outbreak. Strengthening community surveillance and incorporating routine skin examinations into Community-based Health Planning and Services outreach could improve early detection and prevention of similar outbreaks in rural Ghana.

M. Horisberger, J. Rosset

J. Spence

Prisyazhnyuk Anastasia, Vorontsov Victor

Municipal solid waste poses significant environmental challenges due to its wide range and po-tential contaminating impact. Finding sustainable solutions for its disposal is imperative. Moreover, certain types of municipal solMunicipal solid waste poses significant environmental challenges due to its wide range and potential contaminating impact. Finding sustainable solutions for its disposal is imperative. Moreover, certain types of municipal solid waste can serve as valuable resources in the construction sector. This study introduces a novel non-firing binder, devoid of cement, crafted from cullet, caustic alkali, water, and a plasticizing additive. These constituents undergo collaborative wet grinding in a ball mill, achieving a specific surface area of 500–550 m2/kg. Concurrently during milling, glass particles are ground, and amorphous silica is leached with an alkaline solution, yielding a viscous-fluid adhesive mass enriched with siliceous compounds. This mass fills metal mold cells; upon attaining stripping strength, samples undergo heat treatment (drying) up to 90ºC. During this process, sols transform into polysilicic acid gels, which, after 5–6 hours, partially crystallize, achieving requisite strength. The resulting binder, produced without firing, boasts a compressive strength of approximately 25 MPa and a water resistance coefficient of 0.89. Suitable for low-grade concrete production (including glass concrete, fine-grained concrete, and foam concrete), its microstructure was analyzed via scanning electron microscopy, affirming the effective utilization of cullet in construction materials.id waste can serve as valuable resources in the con-struction sector. This study introduces a novel non-firing binder, devoid of cement, crafted from cullet, caustic alkali, water, and a plasticizing additive. These constituents undergo col-laborative wet grinding in a ball mill, achieving a specific surface area of 500–550 m2/kg. Concurrently during milling, glass particles are ground, and amorphous silica is leached with an alkaline solution, yielding a viscous-fluid adhesive mass enriched with siliceous compounds. This mass fills metal mold cells; upon attaining stripping strength, samples undergo heat treatment (drying) up to 90ºC. During this process, sols transform into polysilicic acid gels, which, after 5–6 hours, partially crystallize, achieving requisite strength. The resulting binder, produced without firing, boasts a compressive strength of approximately 25 MPa and a water resistance coefficient of 0.89. Suitable for low-grade concrete production (including glass con-crete, fine-grained concrete, and foam concrete), its microstructure was analyzed via scanning electron microscopy, affirming the effective utilization of cullet in construction materials.

Alfonso J Carrillo, María Balaguer, Cecilia Solís et al.

Nanoparticle exsolution is a powerful technique for functionalizing redox oxides in energy applications, particularly at high temperatures. It shows promise for solid oxide fuel cells and electrolyzers. However, exsolution of other chemistries like metal oxides is not well studied, and the mechanism is poorly understood. This work explores oxide exsolution in PrBa _1− _x Co _2 O _6− _δ ( x = 0, 0.05, 0.1, 0.15) double perovskites, practiced electrodes in proton ceramic fuel cells and electrolyzers. Oxide exsolution in PrBa _1− _x Co _2 O _6− _δ aimed at boosting the electrocatalytic activity and was evaluated by varying intrinsic materials-related properties, viz. A-site deficiency and external parameters (temperature, under fixed time, and p O _2 = 10 ^−5 atm conditions). The materials were analyzed with conventional characterization tools and synchrotron-based small-angle x-ray scattering. Unlike metal-nanoparticle exsolution, increasing the A-site deficiency did not enhance the extent of oxide-nanoparticle exsolution, whereas larger nanoparticles were obtained by increasing the exsolution temperature. Combined Raman spectroscopy and electron microscopy analysis revealed that BaCoO _3 , Co _3 O _4 , and amorphous BaCO _3 nanoparticles were formed on the surface of the double perovskites after the reductive treatments. The present results demonstrate the complexity of oxide-nanoparticle exsolution in comparison with metal-nanoparticle exsolution. Further materials screening and mechanistic studies are needed to enhance our understanding of this method for functionalizing proton ceramic electrochemical cells (PCEC) electrodes.

Pooja Singh, Lokendra Singh, Sameer Yadav et al.

A serious worldwide health concern, tuberculosis (TB) necessitates creative methods for quick and precise diagnosis. This paper presents the detection of Mycobacterium tuberculosis (mTB) using a two-way approach utilizing refractive index (RI) sensors and machine learning (ML) techniques. The approach is validated by adopting a Fano resonance (FR) sensor which consists of freshly prepared cerium oxide nanostructures (CNS) covered sensing slots. The CNS is prepared by using combustion technique and characterized through transmission electron microscopy (TEM) and x-ray diffraction (XRD). The RI values sensed through the sensor yield a high sensitivity and autocorrelation coefficient of 163 nm RIU ^−1 and ${R}^{2}=92.37\, \% $ , respectively. The microscopic sputum smear examination is used to detect mTB through five different ML classifiers. Among all, the random forest classifier provides the highest accuracy of 96%. According to preliminary findings, the suggested system provides a quick, affordable, and non-invasive diagnostic option with excellent accuracy, sensitivity, and specificity. The approach addresses important TB diagnostic problems and is more suitable for low-resource environments. This hybrid strategy can transform TB detection, enhance patient outcomes, and support TB control initiatives.

Fumihiro Ishikawa, Kanji Takahashi, Akiko Takaya et al.

P. Hansma, V. Elings, O. Marti et al.

Ana Alice Venancio Correia, Luís André de Almeida Campos, Hanne Lazla Rafael de Queiroz Macêdo et al.

The present study aimed to evaluate the in vitro antibacterial and antibiofilm activity of bacterial cellulose hydrogel produced by <i>Zoogloea</i> sp. (HYDROGEL) containing vancomycin (VAN) against bacterial strains that cause wound infections, such as multidrug-resistant (MDR) <i>Staphylococcus aureus</i> and <i>Staphylococcus epidermidis</i>. Initially, HYDROGEL was obtained from sugar cane molasses, and scanning electron microscopy (SEM) was performed to determine morphological characteristics. Then, VAN was incorporated into HYDROGEL (VAN-HYDROGEL). The antibacterial activity of VAN, HYDROGEL, and VAN-HYDROGEL was assessed using the broth microdilution method to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) against methicillin-sensitive <i>S. aureus</i> (MSSA) ATCC 25923, methicillin-resistant <i>S. aureus</i> (MRSA) ATCC 33591, <i>S. epidermidis</i> INCQS 00016 (ATCC 12228), five clinical isolates of MRSA, and nine clinical isolates of methicillin-resistant <i>S. epidermidis</i>, following the Clinical and Laboratory Standards Institute (CLSI) guidelines. Additionally, the antibacterial activity of VAN, HYDROGEL, and VAN-HYDROGEL was studied using the time-kill assay. Subsequently, the antibiofilm activity of VAN, HYDROGEL, and VAN-HYDROGEL was evaluated using crystal violet and Congo red methods, as well as SEM analysis. VAN and VAN-HYDROGEL showed bacteriostatic and bactericidal activity against MRSA and methicillin-resistant <i>S. epidermidis</i> strains. HYDROGEL did not show any antibacterial activity. Analysis of the time-kill assay indicated that HYDROGEL maintained the antibacterial efficacy of VAN, highlighting its efficiency as a promising carrier. Regarding antibiofilm activity, VAN and HYDROGEL inhibited biofilm formation but did not demonstrate biofilm eradication activity against methicillin-resistant <i>S. aureus</i> and <i>S. epidermidis</i> strains. However, it was observed that the biofilm eradication potential of VAN was enhanced after incorporation into HYDROGEL, a result also proven through images obtained by SEM. From the methods carried out in this study, it was possible to observe that HYDROGEL preserved the antibacterial activity of vancomycin, aside from exhibiting antibiofilm activity and enhancing the antibiofilm effect of VAN. In conclusion, this study demonstrated the potential of HYDROGEL as a candidate and/or vehicle for antibiotics against MDR bacteria that cause wound infections.

Hugo Caetano, Luís Vilhena, Amílcar Ramalho et al.

Steel structures are vulnerable to fire due to the degradation of their mechanical properties at high temperatures, making it necessary to protect them when exposed to high temperatures. This paper presents the results of an experimental research work to characterise the mechanical properties of gypsum-based fire-resistant mortars with and without nano and micro silica particles by destructive and non-destructive tests at ambient temperature. Five compositions were studied: one commercial composition was used as a reference and four were developed in the laboratory. Two were based on gypsum with perlite or vermiculite, and the other two included nano and micro silica particles. Twenty specimens underwent ultrasonic pulse velocity, flexural, and compression tests, while five specimens were tested by the impulse excitation of vibration. Young’s modulus, shear modulus, and Poisson’s ratio were assessed by non-destructive tests, and the flexural and compression strengths were assessed by destructive tests. Additional tests included density and porosity assessments, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. Results indicated that adding nano and micro silica particles posed challenges to the mechanical and physical properties. Despite this, vermiculite compositions showcased superior or similar properties to the commercial composition, while perlite compositions exhibited slightly lower properties.

Haohan Wang, Lei Zhou, Zheming Zhu et al.

Rock mass may be exposed to high temperature and cooled by water in fire, geothermal resource exploitation and deep underground engineering, which affects the safety of these engineering. In this study, cracked straight through Brazilian disc (CSTBD) specimen was used to study the fracture properties of granite treated with different water-cooling time from 25 °C to 800 °C. A camera was used to record the fracture process of the specimen, the evolution of strain at the specimen surface was obtained by using digital image correlation technology, and the morphological characteristics of fracture surface were observed by using scanning electron microscopy. The results show that water-cooling time has some effects on fracture properties of granite, but its effect is less than the temperature. With the increase of water-cooling time, the mode I fracture toughness decreases first, then increases and finally decreases at the same temperature, and the fracture toughness ranges from 0.419 MPa m1/2 to 0.567 MPa m1/2 at 400 °C. The crack tip opening displacement (CTOD), crack propagation path and fracture surface are related to the energy released during the specimen failure. When the temperature is 25 °C or 200 °C, the energy released is large and the fracture surface is relatively flat with irregular sharp edges, the main cracks are straight lines. At 600 °C, the main crack is zigzag, the CTOD and the maximum principal strain in order can reach 0.143 mm and 0.731 %. This study can help to understand the effect of water-cooling time on engineering rock mass.

Nada M. Al‐Ananzeh, Khalid Bani‐Melhem, Hussam Elddin Khasawneh et al.

Abstract Jordan's energy sector faces significant challenges due to rising fuel prices, making the exploration of local energy resources crucial. The abundant oil shale deposits in Wadi Thamad present a promising opportunity. Since Wadi Thamad oil shale has never been studied before, this research focuses on the Wadi Thamad basin near Madaba, Jordan, aiming to comprehensively characterize its oil shale using advanced analytical techniques. Using X‐ray diffraction, Fourier transform infrared spectroscopy, X‐ray fluorescence, scanning electron microscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry, this study assesses the mineralogical, chemical, and thermal properties of Wadi Thamad oil shale. The findings reveal calcite and quartz as the primary minerals, with significant aliphatic, CO2, hydroxyl, and carboxyl groups. Elemental analysis highlights essential oxides, such as CaO and SiO2. Fischer assay results indicate an oil content of 5.3–10.1 wt%, a gross‐calorific value of 4.56–7.69 MJ/kg, and a sulfur content of 1.77–2.10 wt%. The peak pyrolysis temperature is 432.4°C from TGA. This research's novelty lies in its comprehensive approach to characterizing the underexplored Wadi Thamad oil shale basin. The findings enhance the understanding of Wadi Thamad's geological composition and underscore its potential as a local energy resource, contributing valuable data to Jordan's energy portfolio and offering economic benefits.

D. Sarid

Davood Rahmatabadi, Kianoosh Soltanmohammadi, Mohammad Aberoumand et al.

Abstract Unmodified polyvinyl chloride (PVC) has low thermal stability and high hardness. Therefore, using plasticizers as well as thermal stabilizers is inevitable, while it causes serious environmental and health issues. In this work, for the first time, pure food‐grade PVC with potential biomedical applications is processed and 3D printed. Samples are successfully 3D printed using different printing parameters, including velocity, raster angle, nozzle diameter, and layer thickness, and their mechanical properties are investigated in compression, bending, and tension modes. Scanning electron microscopy is also used to evaluate the bonding and microstructure of the printed layers. Among the mentioned printing parameters, raster angle and printing velocity influence the mechanical properties significantly, whereas the layer thickness and nozzle diameter has a little effect. Images from scanning electron microscopy  also reveal that printing velocity greatly affects the final part's quality regarding defective voids and rasters’ bonding. The maximum tensile strength of 88.55 MPa is achieved, which implies the superiority of 3D‐printed PVC mechanical properties compared to other commercial filaments. This study opens an avenue to additively manufacture PVC that is the second most‐consumed polymer with cost‐effective and high‐strength features.

Bin Qiao, Tao Lv

Titanium and its alloys have been widely adopted in dental prosthetics due to their excellent biocompatibility, light weight, high resilience and good corrosion resistance. The human oral cavity is the second largest microbial host system after the human intestine, with a large number of microbial species. This complex environment of multiple groups of microorganisms promotes the formation of biofilms on the surface of oral implant titanium materials, leading to possible peri-implant inflammation which accelerates the surface corrosion of the titanium implant material. Candida albicans is a common fungus, and the study of the interaction between Candida albicans and titanium alloys is of great importance for the later systematic study of the corrosion effect of the fungus on the metal. In this study, fluorescence microscopy, scanning electron microscopy and electrochemical analysis techniques were adopted to systematically study the formation of microbial films of Candida albicans on the surface of titanium-nickel alloy. The electrochemical behavior of the corrosion of titanium-nickel alloy by Candida albicans were investigated with open circuit potential, potentiodynamic polarization curves and electrochemical impedance spectroscopy. The combined action of metabolites produced by Candida albicans, the extracellular polymer matrix and the formation of microbial film led to the changes in the corrosion electrochemistry of titanium-nickel alloy.

J. Pringle, R. Preston, A. Adams et al.

C. Putman, K. V. D. Werf, B. G. Grooth et al.