Non-treated Samples Research Articles

The response of 316 L steel manufactured by selective laser melting route to high-temperature oxidation behaviour: The role of microstructure modification

The current work examines the effect of 316 L steel's microstructure, which is modified through varying scanning angles with the sample surface (HNS (0°), INS (45°), and VNS (90°)) in the selective laser melting (SLM) method and through surface mechanical attrition treatment (SMAT), on its high-temperature oxidation behaviour (at 600–800 °C) is investigated. We have obtained a deeper understanding of the steel's oxidation behaviour by applying various characterisation techniques. The SMATed steel has a ∼ 1000 μm thick deformed layer containing a gradient microstructure, and its topmost layer contains fine twins and nanograins (∼30 nm). The hardness of this surface is ∼1.65 times the non-treated steel's hardness. All samples follow a parabolic rate law during oxidation. The VNS sample unveils the slowest oxidation rate amid the non-treated samples. SMAT increases the activation energy of oxidation. The distribution of elements across the oxidised samples' cross-section shows discontinuous Cr spreading within the oxide layer on the non-treated samples; however, the deformed samples show uniform distribution. Unlike non-SMATed samples, a minute decline in Cr and Mn content is observed underneath the oxide layer on the SMATed samples, confirming their enhanced outward diffusion. The oxide layer on SMATed samples has more Cr- and Mn-rich oxides. These oxides occupy the grain boundaries of the oxidised non-SMATed surfaces, where the micro-pores and cracks are present. Conversely, oxidised SMATed surfaces display uniform, defect-free Cr- and Mn-rich oxides with finer grains. Moreover, the SMATed layer remains reasonably stable during high-temperature oxidation (hardness drop ranges between ∼9 and ∼ 30%).

Comparison of the effect of organic acid mixture on quality parameters of red deer meat and beef

AbstractThis study investigates the effect of 2% lactic acid and 2% ascorbic acid mixture on the quality parameters of red deer meat and beef. After treatment samples were stored at 4 ± 1 °C. The following meat quality parameters were evaluated: pH, color, and microbiological count on days 1, 7, 14, and 21. The results showed that at the end of the experiment, the pH of the treated samples was slightly higher than the non-treated samples, indicating that the lactic acid and ascorbic acid mixture had a mild acidifying effect on the meat. The color of the treated and non-treated samples did not show any significant difference. However, the microbiological count in the treated samples was lower than the non-treated samples. These findings suggest that an acid mixture could be used as a natural preservative to enhance the microbial safety of red deer meat and beef.

Utilization of Ionic Organic Polymer to Improve Performance and Properties of Problematic Soils

Problematic soils with high compressibility and low shear strength are often treated with traditional chemical stabilizing additives such as cement and lime to improve their engineering properties. Polymers were employed to improve and reinforce a variety of material qualities in a wide range of applications. The use of polymer SBS (stabilizer base stabilizer) to improve the characteristics of problematic soils is discussed in this research. Two types of soils were used. The first type, "soil A Burj," is collapsible soil and was collected from Burj El-Arab city, while the second type, "soil B Dam," is fine sand and was obtained from Damietta city. The untreated and treated samples were subjected to sieve analysis, hydrometer, liquid limits, standard compaction, collapse potential (CP), direct shear, California Bearing Ratio (CBR) testing, and SEM, TEM, chemical, and microstructural analysis tests. Three different polymer SBS concentrations in water were used (1:300, 1:150, and 1:10). The results showed that by adding the polymer SBS, LL and OWC decreased exhibiting more plastic behavior compared to the non-treated samples. Also, the CP decreased with adding the polymer SBS, and the degree of collapsibility was enhanced from trouble to moderate trouble condition. The shear strength, internal friction angle, and CBR value were also improved. In summary, the best results were produced when a polymer ratio of 1:150 was used and a curing time of at least 28 days was provided. Doi: 10.28991/CEJ-2023-09-12-05 Full Text: PDF

Effect of Three Different Preservatives on the Microbiota of Shalgam, a Traditional Lactic Acid Fermented Beverage.

Shalgam is a traditional Turkish beverage derived from the natural fermentation of purple carrots (Daucus carota) that boasts valuable antioxidant and prebiotic properties. These features of shalgam increase efforts to enhance its shelf life and ensure safe consumption. In this study, the effects of three different preservatives (sodium benzoate, potassium sorbate, or natamycin) on the physicochemical and microbiological properties of shalgam produced at laboratory scale and stored at room temperature for six months were investigated. Each preservative was used in four different concentrations (25, 100, 400, and 800 mg/L) to assess their impacts on the population of lactic acid bacteria (LAB) and yeast. After determining the total acidity and pH of the samples, colorimetric measurements were performed. The isolated LAB were defined using the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) method. The addition of preservatives did not significantly affect the pH of the shalgam samples (3.44-3.52) compared to the control sample (3.43). However, a slight increase was observed in the total acidity of preservative-treated samples, with the highest level (5.61 g/L lactic acid) recorded in samples containing 100 mg/L sodium benzoate. Lacticaseibacillus paracasei subsp. paracasei, which has the potential to impart probiotic properties to shalgam, was the predominant LAB species in both non-treated and preservative-treated samples. The use of preservatives significantly reduced the total number of yeasts, which may cause spoilage in shalgam. The results indicate that using sodium benzoate at a concentration of 100 mg/L is the optimum method for shalgam production, resulting in the highest total acidity value obtained. Overall, the findings provide a significant contribution to prolonging the shelf life of shalgam, a beverage with immense production and consumption potential worldwide.

Effects of ultrasound and microwave pretreatments of carrot slices before drying on the color indexes and drying rate

The aim of this study was to examine the impacts of microwave pretreatment (MWP) and ultrasonic pretreatment (USP) on drying time (DT), mass transfer kinetics, effective water diffusivity (Deff), rehydration rate, color index (L*, a*, b*), and the surface shrinkage of carrot slices when dried in a hot air dryer (70 °C). The microwave process was performed for 0, 15, 30, 45, and 60 s before drying of carrot slices. In addition, the ultrasound process was performed in an ultrasonic bath (40 kHz and 150 W) for 0, 5, 10, 15, and 20 min. The results confirmed that the MWP and USP decreased the DT (higher water loss) of carrot slices. Deff values for microwave-pretreated slices were considerably higher than those for nontreated carrot slices (p < 0.05). The Deff calculated by Fick's second law was increased from 8.69 × 10−10 to 10.96 × 10−10 m2 s−1, and from 7.56 × 10−10 to 9.39 × 10−10 m2 s−1, for samples pretreated by microwave and ultrasound, respectively. The empirical value for the drying curves were fitted to the common thin film-equations, and Page's equation was the most suitable to describe the dehydration rate of carrot slices. The average rehydration ratio of nontreated, microwave-treated, and ultrasound-treated carrot slices were 432.3 %, 449.2 %, and 360.9 %, respectively. The redness, yellowness, and surface shrinkage parameters of pretreated samples by microwave were higher than the nontreated slices. The lightness and redness parameters of pretreated carrot slices by ultrasound were higher than the nontreated samples under all conditions.

Control of Escherichia coli in Fresh-Cut Mixed Vegetables Using a Combination of Bacteriophage and Carvacrol.

The continual emergence of antibiotic-resistant bacteria and the slow development of new antibiotics has driven the resurgent interest in the potential application of bacteriophages as antimicrobial agents in different medical and industrial sectors. In the present study, the potential of combining phage biocontrol and a natural plant compound (carvacrol) in controlling Escherichia coli on fresh-cut mixed vegetable was evaluated. Four coliphages, designated Escherichia phage SUT_E420, Escherichia phage SUT_E520, Escherichia phage SUT_E1520 and Escherichia phage SUT_E1620, were isolated from raw sewage. Biological characterization revealed that all four phages had a latent period of 20-30 min and a burst size ranging from 116 plaque-forming units (PFU)/colony forming units (CFU) to 441 PFU/CFU. The phages effectively inhibited the growth of respective host bacteria in vitro, especially when used at a high multiplicity of infection (MOI). Based on transmission electron microscopy analysis, all phages were classified as tailed phages in the class of Caudoviricetes. Additionally, next generation sequencing indicated that none of the selected coliphages contained genes encoding virulence or antimicrobial resistance factors, highlighting the suitability of isolated phages as biocontrol agents. When a phage cocktail (~109 PFU/mL) was applied alone onto fresh-cut mixed vegetables artificially contaminated with E. coli, no bacteria were recovered from treated samples on Day 0, followed by a gradual increase in the E. coli population after 24 h of incubation at 8 °C. On the other hand, no significant differences (p < 0.05) were observed between treated and non-treated samples in terms of E. coli viable counts when carvacrol at the minimum inhibitory concentration (MIC) of 6.25 μL/mL was applied alone. When a phage cocktail at an MOI of ~1000 and MIC carvacrol were applied in combination, no E. coli were recovered from treated samples on Day 0 and 1, followed by a slight increase in the E. coli population to approximately 1.2-1.3 log CFU/mL after 48 h of incubation at 8 °C. However, total elimination of E. coli was observed in samples treated with a phage cocktail at a higher MOI of ~2000 and carvacrol at MIC, with a reduction of approximately 4 log CFU/mL observed at the end of Day 3. The results obtained in this study highlight the potential of combined treatment involving phage biocontrol and carvacrol as a new alternative method to reduce E. coli contamination in minimally processed ready-to-eat foods.

High temperature behavior of sodium and potassium volcanic ashes-based alkali-activated materials (Mt. Etna, Italy)

Thermal performances at 1000 °C of volcanic ash-based alkali-activated materials by both sodium or potassium solutions have been tested. Once defined the feasibility for the potassium set, a multidisciplinary characterization including spectroscopic, thermal, mechanical, diffractometric before and after treatment and dilatometric analyses was applied. The formation kinetics of different networks was evaluated. A correlation between the high mechanical properties and the least amount of water was observed in non-treated samples. Treated samples at 1000 °C showed higher compressive strengths due to the crystallization of wollastonite, leucite and nepheline. Thermal stability was observed increased with the solid content in the potassium-based formulations.

Development of Non-Spherical Platinum Nanoparticles on Carbon Supports for Oxygen Reduction Reaction

Proton exchange membrane fuel cells are anticipated to play an important role in decarbonizing the global energy system, but the performance of platinum (Pt) catalysts must be improved to make this technology more economical. Studies have identified non-spherical Pt nanoparticles on carbon supports as promising approaches to address this challenge. However, to realize the full benefits of these strategies, the catalyst synthesis procedures must be successfully simplified and scaled up, and the catalyst must perform well in half and full-cell tests. In this study, a surfactant-free one-pot method is developed to synthesize non-spherical Pt nanoparticles on Ketjen Black carbon, which is either non-treated (Pt/KB), acid-treated (Pt/KB-O), or nitrogen-doped (Pt/KB-N). The catalysts are synthesized in both small and large batches to determine the effect of scaling up the synthesis procedure. The nitrogen-doped carbon support shows a nearly identical morphological structure with uniform distribution of non-spherical Pt nanoparticles for both small and large batches’ synthesis compared with non-treated and acid-treated carbon samples. The comparative oxygen reduction reaction (ORR) activity shows that the Pt/KB-N prepared in small and large batches has better ORR activity, which is likely caused by uniformly distributed non-spherical Pt nanoparticles on the nitrogen-doped carbon support. All three catalysts show similar ORR durability, testing from 0.5–1.0 V, while Pt/KB-O displays slightly better durability from 1.0–1.5 V for carbon corrosion. These results will help inform the implementation of shape-controlled Pt catalysts on modified carbon supports in large scale.

Nonlinear fourth-order elastic characterization of the cornea using torsional wave elastography

Measuring the mechanical nonlinear properties of the cornea remains challenging due to the lack of consensus in the methodology and in the models that effectively predict its behaviour. This study proposed developing a procedure to reconstruct nonlinear fourth-order elastic properties of the cornea based on a mathematical model derived from the theory of Hamilton et al. and using the torsional wave elastography (TWE) technique. In order to validate its diagnostic capability of simulated pathological conditions, two different groups were studied, non-treated cornea samples (n=7), and ammonium hydroxide (NH4OH\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$NH_4OH$$\\end{document}) treated samples (n=7). All the samples were measured in-plane by a torsional wave device by increasing IOP from 5 to 25 mmHg with 5 mmHg steps. The results show a nonlinear variation of the shear wave speed with the IOP, with higher values for higher IOPs. Moreover, the shear wave speed values of the control group were higher than those of the treated group. The study also revealed significant differences between the control and treated groups for the Lamé parameter μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mu$$\\end{document} (25.9–6.52 kPa), third-order elastic constant A (215.09–44.85 kPa), and fourth-order elastic constant D (523.5–129.63 kPa), with p-values of 0.010, 0.024, and 0.032, respectively. These findings demonstrate that the proposed procedure can distinguish between healthy and damaged corneas, making it a promising technique for detecting diseases associated with IOP alteration, such as corneal burns, glaucoma, or ocular hypertension.

The efficiency of UV light-emitting diodes (UV-LED) in decontaminating Campylobacter and Salmonella and natural microbiota in chicken breast, compared to a UV pilot-plant scale device

This study investigated the combined effect of Ultraviolet (UV) light-emitting diode (LED) technology treatment with refrigerated storage of chicken breast meat over 7 days on Campylobacter jejuni, Salmonella enterica serovar Typhimurium, total viable counts (TVC) and total Enterobacteriaceae counts (TEC). An optimised UV-LED treatment at 280 nm for 6 min decreased inoculated S. Typhimurium and C. jejuni populations by 0.6–0.64 log CFU/g, and TVC and TEC population by 1–1.2 log CFU/g in chicken samples. During a 7-day storage at 4 °C, a 0.73 log reduction in C. jejuni was achieved compared with non-treated samples. Moreover, the UV-LED effectiveness to reduce TVC and TEC during refrigerated storage was compared with a conventional UV lamp and a similar efficiency was observed. The impact of UV-LED and UV lamp devices on the microbial community composition of chicken meat during storage was further examined using 16 S rRNA gene amplicon sequencing. Although similar bacterial reductions were observed for both technologies, the microbial communities were impacted differently. Treatment with the UV conventional lamp increased the proportion of Brochothrix spp. In meat samples, whilst Photobacterium spp. Levels were reduced.

High-Pressure Processing of Traditional Hardaliye Drink: Effect on Quality and Shelf-Life Extension.

Hardaliye, as one of the oldest and lesser known traditional beverages, is produced using red grape pomace from wine production. This drink production is achieved through lactic acid fermentation, with the addition of sour cherry leaves and mustard seeds-either heat-treated, grinded, or whole-in various concentrations. Hardaliye has a very short shelf life; thus, efforts have recently been made to process hardaliye with novel processing technologies in order to achieve shelf-life extension. Therefore, the high-hydrostatic-pressure (HHP) processing of hardaliye was performed to determine its impact on important properties, including in microbial inactivation and shelf-life extension, with respect to a Box-Behnken experimental design. Maximum log reductions of 5.38 ± 0.6, 5.10 ± 0.0, 5.05 ± 0.2, and 4.21 ± 0.0 with HHP were obtained for Brettanomyces bruxellensis, total mesophilic aerobic bacteria, Lactobacillus brevis, and total mold and yeast, respectively. The processing parameters of 490 MPa and 29 °C for 15 min were found as the optimal conditions, with the response variables of an optical density at 520 nm and the inactivation of L. brevis. The samples processed at the optimal conditions were stored at both 4 and 22 °C for 228 d. While the non-treated control samples at 4 and 22 °C were spoiled at 15 and 3 d, the HHP-treated samples were spoiled after 228 and 108 d at 4 and 22 °C, respectively.

Encapsulated Zataria multiflora's essential oil inhibited the growth of Aspergillus flavus and reduced aflatoxins levels in contaminated pistachio nut

The essential oil of Zataria multiflora Boiss. (ZEO) was prepared using a British Pharmacopeia-type hydrodistillation apparatus. The ZEO was encapsulated with a natural polymer, chitosan (CS) by oil-in-water emulsification, and ionic cross-linking techniques. The shape and size range of the encapsulated particles were evaluated by Atomic-Force Microscopy (AFM) and Dynamic Light Scattering (DLS) and FT-IR spectroscopy. The AFM analysis of the ZEO encapsulated nano-particles (CS-ZEO) showed spherical shape particles with inner cavities. The mean size of CS-ZEO particles was 293 ± 17 nm according to DLS analysis. The chemical constituent of the oil was analyzed by GC-MS and thymol acetate (32.4%), carvacrol acetate (19.0%), γ-terpinene (18.5%), and ρ-cymene (14.5%) were reported as its major constituents. The non-encapsulated ZEO in the synthesis process was determined to calculate the encapsulation efficiency and loading capacity of the prepared CS-ZEO which were 87.4% and 6%; respectively. In vitro antifungal activity of ZEO and CS-ZEO in growth media against Aspergillus flavus was evaluated with the decrease in fungal mycelial mass. On the other hand, the HPLC results showed the reduction of aflatoxins B1 levels by 95% and 92% at concentrations of 0.8 mg/mL of ZEO and 6.7 mg/mL of CS-ZEO, respectively. The above-mentioned effective concentrations of the ZEO and CS-ZEO, were applied to pistachio samples, which reduced 90.5% and 99.0%, of the aflatoxin B1 levels, respectively compared to non-treated samples. Therefore, we suggest here, the CS-ZEO as a possible natural fungicide with an effective mechanism of lowering aflatoxins production in the contaminated pistachio.

Effect of atmospheric plasma treatment on Mode-I and Mode-II fracture toughness properties of adhesively bonded carbon fiber/PEKK composite joints

This study aims to assess the influence of peel-ply (PP), mechanical abrasion (MA), and atmospheric plasma activation (APA) treatments on Mode-I and Mode-II fracture toughness of carbon fiber/ poly-ether-ketone-ketone (CF/PEKK) composite joints. A comprehensive examination of the topography and wettability of the adherend surfaces is conducted using various methods. The CF/PEKK adherends are produced through an automated fiber placement (AFP) process, and the CF/PEKK bonded joints are prepared using two different structural adhesive films, one of which has a lower strength, while the other has a higher strength. To evaluate their fracture toughness properties, double cantilever beam (DCB) and end-notched flexure (ENF) tests are carried out in accordance with ASTM standards. Acoustic emission sensors are used to monitor the test specimens during DCB tests, allowing for an in-depth evaluation of the failure modes and damage propagations in the joints. The results show that the GIC and GIIC values of the APA-treated CF/PEKK bonded joints are remarkably higher than those of the untreated ones, with a range of improvement of 34.0–84.8 times and 7.5–17.4 times, respectively. Adhesive failure is the dominant failure mode on the surfaces of non-treated (NT) and PP samples, while cohesive failure is more prominent in those treated with MA and APA. The failure modes of the treated samples varied depending on the adhesive used, with APA-treated samples always exhibiting a cohesive failure. It is observed that the AE counts increase more slowly in APA-treated samples compared to MA-treated joints as delamination progresses more slowly with cohesive failure dominant, which leads to a lower release of AE energy.

Evaluating the effect of different physical pretreatments and cooking methods on nutritional (starch digestibility) and physicochemical properties of white rice grains (Fajr cultivar)

The effects of physical pretreatments including steaming, dry heating and a combination thereof (performed at different times) were evaluated on the content of resistant starch (RS), slowly digestible starch (SDS), and rapidly digestible starch (RDS), morphology, crystalline structure, and some other physicochemical properties of uncooked Iranian rice grains (Fajr cultivar). The grains were then subjected to cooking by various methods (i.e., boiling, rinsing, and steam-cooking) to investigate the effect of cooking on the nutritional properties obtained after applying physical pretreatments. Generally, reaction constant (k), hydrolysis index (HI), and estimated glycemic index (eGI) decreased after pretreatments. Physical pretreatments increased R1047/1022. Pretreated and cooked grains had significantly higher RS content (5–20%) than non-treated cooked samples. Morphology and crystalline structure were affected by pretreatments. Cooking by rinsing method is suggested for patients with type 2 diabetes mellitus because of lowering the HI (30%) and eGI (18%). Steam-cooking method is recommended for preparing a dietary rice meal due to the higher RS and SDS content. Pretreatment by steaming and cooking by boiling are suitable for people suffering from chewing problems. In conclusion, applying physical pretreatments and choosing appropriate cooking method can increase RS content, decrease eGI, and hence improve nutritional characteristics of rice grains.

Aqueous polyacrylate latex nanodispersions used as consolidation agents to improve mechanical properties of Prague sandstone

This investigation aims at assessing the potential of polyacrylate latex nanodispersions as consolidation agents for sandstones. Four different latex types, implementing polymer fluorination and chemical crosslinking, have been synthesized at the scope and fully characterized. The Prague sandstone employed in this study has been selected as an example of highly porous stones used as building materials for many historical monuments. Two different concentration levels of nanodispersions have been adopted. The consolidated stone samples have been tested using a combination of physical-mechanical tests and microscopic observations. Compared to the non-treated samples, significant increments of mechanical properties (e.g. up to 3.3 times higher bending strength) have been detected after the consolidation treatment with concentrated products. Moreover, when 10 times diluted latex nanodispersions have been applied, the improvement of mechanical properties has still been significant, while moisture transport properties, such as water absorption, have been found to be comparable with those of the untreated sample. Fluorinated polymers imparted better hydrophobic properties with a contact angle above 100°. Observations using a scanning electron microscope revealed the good filling and bridging capacity of the applied consolidation agents. As demonstrated, by acting on the polymer structure, that is, by tuning the degree of crosslinking, polymer fluorination and gel content, the properties of these novel polyacrylate latex nanodispersions can be tailored to the specific stone and type of decay in order to improve the effectiveness of the treatments and obtain the desired final properties. The flexibility of their chemistry offers new opportunities for preserving objects of cultural heritage that are also at risk due to the ongoing climate change.

Wnt/β-Catenin Signaling Activation Induces Differentiation in Human Limbal Epithelial Stem Cells Cultured Ex Vivo.

Human limbal epithelial stem cells (hLESCs) continuously replenish lost or damaged human corneal epithelial cells. The percentage of stem/progenitor cells in autologous ex vivo expanded tissue is essential for the long-term success of transplantation in patients with limbal epithelial stem cell deficiency. However, the molecular processes governing the stemness and differentiation state of hLESCs remain uncertain. Therefore, we sought to explore the impact of canonical Wnt/β-catenin signaling activation on hLESCs by treating ex vivo expanded hLESC cultures with GSK-3 inhibitor LY2090314. Real-time qRT-PCR and microarray data reveal the downregulation of stemness (TP63), progenitor (SOX9), quiescence (CEBPD), and proliferation (MKI67, PCNA) genes and the upregulation of genes for differentiation (CX43, KRT3) in treated- compared to non-treated samples. The pathway activation was shown by AXIN2 upregulation and enhanced levels of accumulated β-catenin. Immunocytochemistry and Western blot confirmed the findings for most of the above-mentioned markers. The Wnt/β-catenin signaling profile demonstrated an upregulation of WNT1, WNT3, WNT5A, WNT6, and WNT11 gene expression and a downregulation for WNT7A and DKK1 in the treated samples. No significant differences were found for WNT2, WNT16B, WIF1, and DKK2 gene expression. Overall, our results demonstrate that activation of Wnt/β-catenin signaling in ex vivo expanded hLESCs governs the cells towards differentiation and reduces proliferation and stem cell maintenance capability.

Effect of high pressure processing on the inactivation of foodborne pathogens in egg salad.

The objectives of this study were to determine the effect of high pressure processing (HPP) on the survival of Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157: H7 in egg salad, and to evaluate the number of sub-lethally injured cells based on treatment conditions. HPP at 500MPa for 30s was sufficient for the complete inactivation of L. monocytogenes and S. Typhimurium directly plated on selective agar or plated after resuscitation, while 2min treatment was required for E. coli O157: H7. HPP at 600MPa for 30s completely inactivated L. monocytogenes and S. Typhimurium, while 1min treatment was needed for E. coli O157: H7. HPP at 400‒500MPa injured a large number of pathogenic bacteria. No significant changes (p> 0.05) in pH and color of egg salad were observed between HPP-treated and non-treated samples during 28 days of storage at refrigerated temperature. Our findings could be useful in predicting the HPP-mediated inactivation patterns of foodborne pathogens in egg salad for practical applications.

Effects of casein on flammability and mechanical characteristics of medium density fibreboards based on formaldehyde-free resin system

As one of the major milk proteins, casein has mainly been used in food and medical industries. Its applications have also been expanded to other areas, including its use as a textile fibre, coating material and as an adhesive. However, more recently, casein has shown great potential as an alternative flame retardant (FR) because it is non-toxic and biodegradable. Nevertheless, there are limited studies to investigate the effects of casein on flame retardant and mechanical properties of wood-based panels. In this research, we have set up a manufacturing process to fabricate fire resistant medium density fibreboards (MDFs). Casein is used as an FR compound to explore its effects on the fire and mechanical performance of wood-based MDF panels. Moreover, a soy flour-based resin system is selected as a replacement for the commonly used toxic formaldehyde-based resin. Two approaches are employed for the casein incorporation during the MDF manufacturing process: one is to spray casein solutions and another is to add pulverized casein particles. The spraying method with casein solution improves the flexure strength by approximately 48% compared to that of non-treated MDF samples, while the flexure strengths of MDF panels with ground casein particles dropped by nearly 26%. The addition of casein also reduced the heat release rate of the panel with a more compact char structure. The research clearly indicates the possibility of manufacturing fire-retardant casein-based MDF panels for their use in fire-prone areas.

Imaging and photodynamic therapy of prostate cancer using a theranostic PSMA-targeting ligand

PurposeIncomplete resection of prostate cancer (PCa) results in increased risk of disease recurrence. Combined fluorescence-guided surgery with tumor-targeted photodynamic therapy (tPDT) may help to achieve complete tumor eradication. We developed a prostate-specific membrane antigen (PSMA) ligand consisting of a DOTA chelator for 111In labeling and a fluorophore/photosensitizer IRDye700DX (PSMA-N064). We evaluated the efficacy of PSMA-tPDT using PSMA-N064 in cell viability assays, a mouse xenograft model and in an ex vivo incubation study on fresh human PCa tissue.MethodsIn vitro, therapeutic efficacy of PSMA-N064 was evaluated using PSMA-positive LS174T cells and LS174T wild-type cells. In vivo, PSMA-N064-mediated tPDT was tested in immunodeficient BALB/c mice-bearing PSMA-positive LS174T xenografts. Tumor growth and survival were compared to control mice that received either NIR light or ligand injection only. Ex vivo tPDT efficacy was evaluated in excised fresh human PCa tissue incubated with PSMA-N064.ResultsIn vitro, tPDT led to a PSMA-specific light- and ligand dose-dependent loss in cell viability. In vivo, tPDT-induced tumor cell apoptosis, delayed tumor growth, and significantly improved survival (p = 0.004) of the treated PSMA-positive tumor-bearing mice compared with the controls. In fresh ex vivo human PCa tissue, apoptosis was significantly increased in PSMA-tPDT-treated samples compared to non-treated control samples (p = 0.037).ConclusionThis study showed the feasibility of PSMA-N064-mediated tPDT in cell assays, a xenograft model and excised fresh human PCa tissue. This paves the way to investigate the impact of in vivo PSMA-tPDT on surgical outcome in PCa patients.

Surface Alloying of Tool Steels with Ytterbium Pulse Fiber Laser

The present research shows the possibility of using an ytterbium nanosecond pulsed fiber laser for wear resistance improvement of carbon and alloy steels. The wear test was performed in accordance with the block-on-ring scheme with dry sliding friction on a friction machine. Surface dispersing/alloying was carried out from a boron carbide paste. This leads to a significant wear resistance improvement of steels. It was revealed that the mass loss during wear test reduced by several times after laser treatment compared to the non-treated samples. The wear mechanism differs depending on the type of steel and largely refers to their microstructure and composition. The tribo-oxide layer forms during the wear test.