External Surface Research Articles

Investigating the effect of external surface layer on high pressure phase evolution in a single crystal: A mechanics-based phase field study

Investigating the effect of external surface layer on high pressure phase evolution in a single crystal: A mechanics-based phase field study

Effect of Temperature on Nestmate Recognition in the Ant Odontomachus chelifer

Cuticular hydrocarbons play multiple roles in social insects. Their primary function is to waterproof the external surface of the body of individuals in order to prevent desiccation, however, they also act as a chemical signature in social insects, unique to each colony, through which individuals recognize themselves as nestmates. These compounds may undergo changes due to exogenous factors, aiming to maintain the integrity of the cuticle. However, changes in cuticular chemical composition may impair recognition among nestmates. Thus, this study tested the hypothesis that nestmates of the ant Odontomachus chelifer, when submitted to different temperature conditions, may undergo changes in their normal pattern of recognition. To do this, groups of workers were kept under two different temperatures, 15 and 30 °C, during a period of 24 hours, and then submitted to induced encounters with workers who remained for this same period at a temperature of 25 °C. As a form of control, the same type of encounter was performed between ants that remained isolated, but at the same temperature and also between ants from different colonies. The results show that ants that remain for 24 hours under different temperature conditions, present some level of difficulty in recognizing themselves as nestmates, performing more aggressive behaviors and taking longer touching themselves (antennation) than in the control condition.

Targeting plasmid-encoded proteins that contain immunoglobulin-like domains to combat antimicrobial resistance

Antimicrobial resistance (AMR) poses a significant threat to human health. Although vaccines have been developed to combat AMR, it has proven challenging to associate specific vaccine antigens with AMR. Bacterial plasmids play a crucial role in the transmission of AMR. Our recent research has identified a group of bacterial plasmids (specifically, IncHI plasmids) that encode large molecular mass proteins containing bacterial immunoglobulin-like domains. These proteins are found on the external surface of the bacterial cells, such as in the flagella or conjugative pili. In this study, we show that these proteins are antigenic and can protect mice from infection caused by an AMR Salmonella strain harboring one of these plasmids. Furthermore, we successfully generated nanobodies targeting these proteins, that were shown to interfere with the conjugative transfer of IncHI plasmids. Considering that these proteins are also encoded in other groups of plasmids, such as IncA/C and IncP2, targeting them could be a valuable strategy in combating AMR infections caused by bacteria harboring different groups of AMR plasmids. Since the selected antigens are directly linked to AMR itself, the protective effect extends beyond specific microorganisms to include all those carrying the corresponding resistance plasmids.

Targeting plasmid-encoded proteins that contain immunoglobulin-like domains to combat antimicrobial resistance.

Antimicrobial resistance (AMR) poses a significant threat to human health. Although vaccines have been developed to combat AMR, it has proven challenging to associate specific vaccine antigens with AMR. Bacterial plasmids play a crucial role in the transmission of AMR. Our recent research has identified a group of bacterial plasmids (specifically, IncHI plasmids) that encode large molecular mass proteins containing bacterial immunoglobulin-like domains. These proteins are found on the external surface of the bacterial cells, such as in the flagella or conjugative pili. In this study, we show that these proteins are antigenic and can protect mice from infection caused by an AMR Salmonella strain harboring one of these plasmids. Furthermore, we successfully generated nanobodies targeting these proteins, that were shown to interfere with the conjugative transfer of IncHI plasmids. Considering that these proteins are also encoded in other groups of plasmids, such as IncA/C and IncP2, targeting them could be a valuable strategy in combating AMR infections caused by bacteria harboring different groups of AMR plasmids. Since the selected antigens are directly linked to AMR itself, the protective effect extends beyond specific microorganisms to include all those carrying the corresponding resistance plasmids.

Isolation and Diagnosis of Parasites from Domestic Cockroach Periplaneta americana in Mosul city, Iraq

Cockroaches are the greatest potential mechanical vector of various pathogenic microorganisms, some of which cause serious diseases in humans and domestic animals. The high prevalence of human pathogens carried by the cockroach has been reported in many countries. This study aimed to determine the prevalence of internal and external parasites parasitizing the American cockroach, Periplaneta americana, the effect of the sex of the cockroach and the area of sample collection on The type, number and types of parasites isolated, The current study was conducted for the period from July 2023 until April 2024, A samples of 111 male Periplaneta americana cockroaches were collected from some homes and schools in the city of Mosul. After the samples arrived at the laboratory, by placing them in clean, sterilized tubes in a refrigerator set at -4°C for 10 minutes Subsequently, 10 ml of normal saline solution was added to each tube. The tubes were then vigorously shaken for 5 minutes to dislodge parasites a salt solution was added to centrifuge tubes, which were spun at 2000 rotations per minute for 5 minutes. This mixture was shaken for 5 minutes and then, Cockroaches were dissected to isolate internal parasites The contents of the digestive tract were taken, and the solution was filtered through a mesh. Each sample was prepared by placing a drop of sediment on a glass slide, adding Lugol's iodine dye, and examining it under a microscope. The majority of the samples were infected with one or more types of parasites on their body surfaces and within their digestive tracts, infection rate of 96.40 %. This study involved the isolation and diagnosis of 19 parasitic species, including five types of worms: Ancylostoma duodenale, Leidynema, Strongyloides stercoralis, Hammerschmidtiella male, and Thelastoma. and six types of protozoan parasites, including both active and Nyctotherus ovalis cyst, active and cyst stages of Lophmonas, cyst stage of Entamoeba coli, and Gregarine. and Seven types of eggs, comprising eggs of each of Ancylostoma duodenale, Thelastoma, Leidynema, Strongyloides stercoralis, Hammerschmidtiella , Gryllophila, and in addition to the external parasitic Mite, The highest infection rate was recorded in worms, with 91 out of 111 samples i.e. (81.98% ). This was followed by protozoa, with a rate of 72% out of 80 samples. Finally, external mites, 52 samples i.e. (46.84%). In this study, it was observed that the number of parasites harbored by cockroaches in their digestive tracts exceeds more than that found on their external surfaces. Cockroaches collected from households were found to harbor a greater number of parasites compared to those collected from schools, underscoring the necessity of raising awareness about the dangers of cockroach presence in homes and keeping them away from food sources due to the parasites they carry, which may cause various diseases.

Impact of Calcined Natural Clinoptilolite Zeolite on Hydration Kinetics and Shrinkage of Cementitious Materials

Abstract Previous literature has provided contradictory results, so we present the current investigation to provide additional information to assess the suitability of using soak calcination as a pretreatment method to increase the performance of calcined zeolite when used as the supplementary cementitious material. In this study, natural clinoptilolite zeolite was calcined for three hours at 200°C, 400°C, 600°C, 800°C, and 1,000°C, and the effects of calcination on different physical and chemical properties were observed using a range of experimental tests. The impacts of calcined zeolite were investigated in the hydrated system with the replacement of portland cement up to 20 % by mass on hydration kinetics (i.e., heat of hydration, setting time, chemical shrinkage, degree of hydration), drying shrinkage, and compressive strength. Results revealed that calcination minorly decreased the crystallinity, particle size, and peak pore size of the zeolite, leading to a slightly increased external specific surface area, whereas it increased the rate of moisture absorption and pH of zeolite particles. In the hydrated cementitious system, calcined zeolite reduced the workability and heat of hydration and retarded the initial setting time. The calcined zeolite particles absorbed a part of the water from the fresh mixture and expanded volumetrically, which led to a negative volume of chemical shrinkage up to the final setting time and increased the drying shrinkage. As the dosages of calcined zeolite increased, the compressive strength substantially decreased because of the lower degree of hydration. Overall, soak calcination pretreatment decreased the reactivity of clinoptilolite zeolite particles and impacted the performance of calcined zeolite in the blended system.

Study of Heat Flow at Substrate during Sputtering of Copper-Titanium Sandwich Target.

The purpose of this work is to study the kinetics of the heat flow heating the substrate, which is generated by a two-layer sandwich magnetron target when sputtered in argon. Its novelty resides in the application of the COMSOL Multiphysics to study the kinetics of thermal processes during sputtering of a target of the new type. The analysis was performed for a sandwich target with internal copper and external titanium plates when the discharge power varied in the range of 400-1200 W. The heating of the external target plate is described by a two-dimensional homogeneous Fourier equation. The solution to the equation reveals how the kinetics of the external plate's surface temperature distribution depends on the discharge power. To study the heat flow heating the substrate, the external plate is presented in the form of an additive set of small-sized surface heat sources. Previously unknown features of the thermal process are established. It is shown that numerical modeling adequately describes the experimental results.

Detection and genetic characterization of chicken astrovirus and avian nephritis virus from hatchery to farm

ABSTRACT Astroviruses are an emerging hazard in hatchery management, and they are responsible for great economic losses in poultry farms worldwide. Chicken astrovirus (CAstV) and avian nephritis virus (ANV) are involved in decreased hatching rate, mainly due to embryo deaths, and pale and runted chicks too weak to hatch. Hatchery diseases occur through direct egg infection or vertical transmission. However, the specific role of astroviruses in these diseases is still largely unknown. To elucidate this a high-quality Piedmont hatchery (Italy) was selected based on farm clinical signs and the astrovirus serological positivity in the breeder farm. The viral dynamics were followed from the hatchery to the farm. The presence of both CAstV and ANV was monitored by evaluating the viral load in environmental and bird samples. Interestingly, both viruses were detected in chick yolk sacs at 18 days of incubation, and in the gut contents of 1-day chicks, whereas in the hatchery environmental samples, the eggs' external surfaces and the embryos’ intestinal contents were negative. The CAstV copy number was higher in bird tissues from the hatchery, while a greater ANV load was detected in bird tissues from the farm. Moreover, our data suggest vertical transmission of both viruses. Frequent co-infection was also observed in samples from both the hatchery and the farm. Lastly, the first Italian full-length genome and molecular characterization of ANV was obtained. RESEARCH HIGHLIGHTS Identified the role of the hatchery in astrovirus transmission. Sequenced the avian nephritis virus complete genome. Investigated tissue distribution of astrovirus from egg to chicks. Demonstrated co-infection of ANV/CAstV.

A geometrical theory of gliding motility based on cell shape and surface flow

Gliding motility proceeds with little changes in cell shape and often results from actively driven surface flows of adhesins binding to the extracellular environment. It allows for fast movement over surfaces or through tissue, especially for the eukaryotic parasites from the phylum apicomplexa, which includes the causative agents of the widespread diseases malaria and toxoplasmosis. We have developed a fully three-dimensional active particle theory which connects the self-organized, actively driven surface flow over a fixed cell shape to the resulting global motility patterns. Our analytical solutions and numerical simulations show that straight motion without rotation is unstable for simple shapes and that straight cell shapes tend to lead to pure rotations. This suggests that the curved shapes of Plasmodium sporozoites and Toxoplasma tachyzoites are evolutionary adaptations to avoid rotations without translation. Gliding motility is also used by certain myxo- or flavobacteria, which predominantly move on flat external surfaces and with higher control of cell surface flow through internal tracks. We extend our theory for these cases. We again find a competition between rotation and translation and predict the effect of internal track geometry on overall forward speed. While specific mechanisms might vary across species, in general, our geometrical theory predicts and explains the rotational, circular, and helical trajectories which are commonly observed for microgliders. Our theory could also be used to design synthetic microgliders.

Tarnished jewellery and skin - a subtle external marker indicating exposure to hydrogen sulfide.

A 39-year-old woman was found lying in the rear of a car at her home address. A smell of rotten eggs was noted and bottles of brick, tile and paver cleaner and lime sulfur were found in the rear of the vehicle. Suicide notes were found in the house. At autopsy there was no evidence of significant trauma with black tarnishing of a silver-coloured ring and a silver-coloured necklace noted with staining of the underlying skin, in keeping with a chemical reaction between hydrogen sulfide and silver. Internally the most significant finding was unusual greenish discolouration of the gray matter of the external and cut surfaces of the cerebral hemispheres, cerebellum and brain stem. No other organs had this discoloration. Death was attributed to hydrogen sulfide poisoning. Skin discoloration from silver jewellery may represent a subtle external marker for lethal or non-lethal hydrogen sulfide exposure.

The Horizons of Medical Mineralogy: Structure-Bioactivity Relationship and Biomedical Applications of Halloysite Nanoclay.

Medical mineralogy explores the interactions between natural minerals and living organisms such as cells, tissues, and organs and develops therapeutic and diagnostic applications in drug delivery, medical devices, and healthcare materials. Many minerals (especially clays) have been recognized for pharmacological activities and therapeutic potential. Halloysite clay (Chinese medicine name: Chishizhi), manifested as one-dimensional aluminum silicate nanotubes (halloysite nanotubes, HNTs), has gained applications in hemostasis, wound repair, gastrointestinal diseases, tissue engineering, detection and sensing, cosmetics, and daily chemicals formulations. Various biomedical applications of HNTs are derived from hollow tubular structures, high mechanical strength, good biocompatibility, bioactivity, and unique surface characteristics. This natural nanomaterial is safe, abundantly available, and may be processed with environmentally safe green chemistry methods. This review describes the structure and physicochemical properties of HNTs relative to bioactivity. We discuss surface area, porosity and surface defects, hydrophilicity, heterogeneity and charge of external and internal surfaces, as well as biosafety. The paper provides comprehensive guidance for the development of this tubule nanoclay and its advanced biomedical applications for clinical diagnosis and therapy.

ROS-responsive charge reversal mesoporous silica nanoparticles as promising drug delivery system for neovascular retinal diseases

Intravitreal injection of biodegradable implant drug carriers shows promise in reducing the injection frequency for neovascular retinal diseases. However, current intravitreal ocular devices have limitations in adjusting drug release rates for individual patients, thereby affecting treatment effectiveness. Accordingly, we developed mesoporous silica nanoparticles (MSNs) featuring a surface that reverse its charge in response to reactive oxygen species (ROS) for efficient delivery of humanin peptide (HN) to retinal epithelial cells (ARPE-19). The MSN core, designed with a pore size of 2.8 nm, ensures a high HN loading capacity 64.4% (w/w). We fine-tuned the external surface of the MSNs by incorporating 20% Acetyl-L-arginine (Ar) to create a partial positive charge, while 80% conjugated thioketal (TK) methoxy polyethylene glycol (mPEG) act as ROS gatekeeper. Ex vivo experiments using bovine eyes revealed the immobilization of Ar-MSNs-TK-PEG (mean zeta potential: 2 mV) in the negatively charged vitreous. However, oxidative stress reversed the surface charge to −25 mV by mPEG loss, facilitating the diffusion of the nanoparticles impeded with HN. In vitro studies showed that ARPE-19 cells effectively internalize HN-loaded Ar-MSNs-TK, subsequently releasing the peptide, which offered protection against oxidative stress-induced apoptosis, as evidenced by reduced TUNEL and caspase3 activation. The inhibition of retinal neovascularization was further validated in an in vivo oxygen-induced retinopathy (OIR) mouse model.

Electrochemical Anion Sensing Using Conductive Metal-Organic Framework Nanocrystals with Confined Pores.

Anion sensing technology is motivated by the widespread and critical roles played by anions in biological systems and the environment. Electrochemical approaches comprise a major portion of this field but so far have relied on redox-active molecules appended to electrodes that often lack the ability to produce mixtures of distinct signatures from mixtures of different anions. Here, nanocrystalline films of the conductive metal-organic framework (MOF) Cr(1,2,3-triazolate)2 are used to differentiate anions based on size, which consequently affect the reversible oxidation of the MOF. During framework oxidation, the intercalation of larger charge-balancing anions (e.g., ClO4-, PF6-, and OTf-) gives rise to redox potentials shifted anodically by hundreds of mV due to the additional work of solvent reorganization and anion desolvation. Smaller anions (e.g., BF4-) may enter partially solvated, while larger ansions (e.g., OTf-) intercalate with complete desolvation. As a proof-of-concept, we leverage this "nanoconfinement" approach to report an electrochemical ClO4- sensor in aqueous media that is recyclable, reusable, and sensitive to sub-100-nM concentrations. Taken together, these results exemplify an unusual combination of distinct external versus internal surface chemistry in MOF nanocrystals and the interfacial chemistry they enable as a novel supramolecular approach for redox voltammetric anion sensing.

A novel theory for rapid localization of the transverse-sigmoid sinus junction and “keyhole” in the retrosigmoid keyhole approach: micro-anatomical study, technique nuances, and clinical application

To determine a rapid and accurate method for locating the keypoint and “keyhole” in the suboccipital retrosigmoid keyhole approach. (1) Twelve adult skull specimens were selected to locate the anatomical landmarks on the external surface of the skull.The line between the infraorbital margin and superior margin of the external acoustic meatus was named the baseline. A coordinate system was established using the baseline and its perpendicular line through the top point of diagastric groove.The perpendicular distance (x), and the horizontal distance (y) between the central point of the “keyhole” and the top point of the digastric groove in that coordinate system were measured. The method was applied to fresh cadaveric specimens and 53 clinical cases to evaluate its application value. (1) x and y were 14.20 ± 2.63 mm and 6.54 ± 1.83 mm, respectively (left) and 14.95 ± 2.53 mm and 6.65 ± 1.61 mm, respectively (right). There was no significant difference between the left and right sides of the skull (P > 0.05). (2) The operative area was satisfactorily exposed in the fresh cadaveric specimens, and no venous sinus injury was observed. (3) In clinical practice, drilling did not cause injury to venous sinuses, the mean diameter of the bone windows was 2.0–2.5 cm, the mean craniotomy time was 26.01 ± 3.46 min, and the transverse and sigmoid sinuses of 47 patients were well-exposed. We propose a “one point, two lines, and two distances” for “keyhole” localization theory, that is we use the baseline between the infraorbital margin and superior margin of the external acoustic meatus and the perpendicular line to the baseline through the top point of the digastric groove to establish a coordinate system. And the drilling point was 14.0 mm above and 6.5 mm behind the top point of the digastric groove in the coordinate system.

Oxygen corrosion of reboiler tube served in production of dilution steam from heat exchanger of petrochemical refinery

This paper reports the oxygen corrosion of heat exchanger tubes serviced in dilute steam generation system. The floating head heat exchanger employed in a petrochemical industry underwent remnant corrosion failures particularly at lower passes of tube bundle. Initially remote field eddy current inspection technique was employed for tube bundle conditional assessment and further, root cause of degradation of tube had been analyzed. Comprehensive experimental techniques including visual examination, tube chemistry analysis, external tube surface morphological analysis, elemental mapping, scanning electron microscopy, light microscopy and x-ray diffraction studies were employed. The tube surface at the degraded position with its cross sectional examination was rigorously evaluated as well. Moreover, actual steam parameters such as pH, conductivity and iron & chloride concentration have been monitored in the petrochemical facility. The detailed analysis concluded that dissolved oxygen in boiler feed water (BFW) was the root cause for corrosion failure. Several other foreign elements were detected and source of each element was discussed in the context of actual heat exchanger operating conditions. Simulated conditions of BFW service have electrochemically been evaluated in two different dissolved oxygen concentrations at 7.5 ppm and 12.7 ppm, respectively. Even small increase of dissolved oxygen in BFW could lead to promotion of oxygen reduction reaction. Theoretically SA179 tubes operated at pH of 9.75 could lead to formation of bicarbonate and it could protect the tube in absence of dissolved oxygen as evaluated by Molecular Dynamics simulation. However, according to obtained results, tube has been degraded due to presence of dissolved oxygen in BFW. Various contributing factors such as external paint/coat removal, absence of de-aerator system in BFW treatment and improper corrosion inhibitor programme were discussed. Several practical countermeasures have been suggested to mitigate oxygen corrosion failure in petrochemical refineries.

Regenerative cooling in hybrid rocket engines based on Self-Pressurized liquid nitrous oxide

An experimental investigation of the reliability and feasibility of a regenerative cooling system in hybrid rocket engines based on saturated nitrous oxide is presented. The novelty of the work consists in the use of a cooling system based on saturated liquid nitrous oxide, wrapping the external surface of a COTS graphite nozzle. The detrimental heat fluxes developed at the throat are handled with a slight increase in assembly complexity. Ten firing tests are performed with an incremental logic of the mass flow rate from 9 to 45 g/s, which is controlled by cavitating the fluid through orifices with different diameters upstream of the cooling system. The tests have been performed at different ambient temperatures in different seasons. The multiphase state of the coolant is evaluated by measuring pressure and temperature upstream and downstream of the cavitation orifice and cooling channels. The test with the smallest mass flow rate developed the highest vapour fraction downstream of the orifice and cooling channels at 0.458 and 0.481, respectively. The cooling performance is indirectly evaluated by measuring the nozzle temperature at 3, 5, and 8.5 mm from the throat internal surface. The results show that steady temperatures are achieved inside the nozzle, with throat temperatures included between 700 and 1200 K in a chamber pressure range between 5 and 30 bar. Nozzle erosion never occurs in the entire experimental campaign, and the nozzles are totally reusable for more ignitions. The coolant heat transfer coefficient increased from 3912 to 21181 W/(m2∙K) by increasing the flow rate per channel from around 3 to 15 g/s. Compared to cryogenic oxygen, liquid nitrous oxide displays higher cooling performance. Finally, the cavitation orifice is moved downstream of the cooling system, showing worse performance of the overall propulsion system.

Properties of encapsulated raspberry powder and its efficacy for improving the pH, colour quality and shelf life of modified atmosphere packaged chicken nuggets

ABSTRACT 1. Recent research has shown that encapsulated raspberry powder (RP) is a natural colourant for foodstuffs. However, no research has been conducted on its use in chicken nuggets. In addition, the effect of RP on products with and without phosphate addition is unknown. This study assessed the effects of RP (control, 0.5%, 1.0%) and phosphate (0.0%, 0.3%) on the pH and colour quality properties of nuggets. 2. In the production of RP, red raspberry (Rubus ideaus L.) juices were encapsulated using maltodextrin in a spray-dryer. Antioxidant activity, total anthocyanin, total phenolics, colour, moisture and pH analyses of the RP were performed. 3. Nuggets were packaged in modified atmosphere packaging (MAP; 40%CO2 + 60%N2) and were stored at 2.0 ± 0.5°C for 120 d. The pH and external and internal surface colour (L*, a*, b*, C* and h) values were measured on d 0, 15, 30, 45, 60, 75, 90, 105 and 120 of storage. 4. The addition of phosphate increased the pH in the samples, while these decreased with the addition of RP (p < 0.05). During storage, the highest pH were seen in the phosphate samples and the lowest in the nuggets with 1.0% RP addition (p < 0.05). 5. With the addition of phosphate, the external surface a* value of nuggets increased (p < 0.05). Depending on the level of RP added to the nuggets, the external surface L* value decreased and a* and b* values increased (p < 0.05). After d 30 of storage, the a* value increased in the samples with RP addition and this increase was higher in the with phosphate nuggets (p < 0.05). 6. The internal surface a* value increased with the addition of RP during nugget production (p < 0.05). The increase in a* value was greater in samples with added phosphate (p < 0.05). During storage, the highest a* values were seen in nuggets treated with phosphate + 0.1% RP (p < 0.05). The addition of RP to chicken nugget emulsion improved redness, colour stability and shelf life.

Prevalence and antimicrobial susceptibility patterns of bacteria colonizing the external ocular surfaces of patients undergoing ocular surgeries at Bugando Medical Center in Mwanza, Tanzania

ObjectiveUnderstanding microbiota colonizing ocular surfaces is key to expedite antibiotic prophylactic options for ocular surgeries, and therefore, prevent subsequent surgical site infections (SSIs). To fill this critical gap, we aimed at determining the prevalence and antibiotic susceptibility patterns of bacteria colonizing the external ocular surfaces of 224 patients undergoing ocular surgeries at Bugando Medical Centre (BMC) in Mwanza, Tanzania between May and August 2023.ResultsThe study participants had a median age of 62.5 (interquartile range: 39.5–75.0) years. A total of 78.1% (175/224) ocular swabs were culture positive yielding 196 bacterial isolates. Staphylococcus epidermidis [43.4% (n = 85)], Staphylococcus aureus [21.9% (n = 43)] and Pseudomonas aeruginosa [14.3% (n = 28)] were the most common bacteria. There were low proportions of resistance among predominant Gram-positive and Gram-negative bacteria to gentamicin (≤ 25.0%), and similarly, low resistance among Gram negative bacteria was observed against 3rd generation cephalosporins (≤ 25.0%) and piperacillin-tazobactam (0.0%). Variable resistance profiles were notable to the most commonly used antibiotics (ciprofloxacin and tetracycline: 0.0–66.7%). Our findings underscore an urgent need to revisit antibiotic prophylactic guidelines for ocular surgeries in this tertiary hospital, and calls for prospective evaluation of incident SSIs post-ocular surgeries to guide specific management.

Quinizarin-based photoactive porous polymers from emulsion templates: Monoliths versus membranes in photobactericidal applications

The increasing challenge of antimicrobial resistance and the persistent threat of infectious diseases are strong incentives for development of novel materials that effectively and sustainably combat bacterial proliferation. Macroporous materials contribute to this endeavor, but the reported antibacterial porous polymers rely on the release of antibacterial agents, which carries the risk that their efficacy will diminish over time. This work reports a facile synthesis by emulsion templating polymerization of innovative photo-bactericidal macroporous polymers functionalized by a quinizarin photosensitizer that generates antibacterial reactive oxygen species under visible light. In brief, a monomethacrylated quinizarin (QMA) derivative, known for its ability to generate bactericidal singlet oxygen upon visible light irradiation, is copolymerized with a bio-based acrylated epoxidized soybean oil (AESO) under high internal phase emulsion (HIPE) conditions, resulting in 3D-interconnected quinizarin-functionalized macroporous monoliths. The QMA-functionalized polyHIPEs are also structured into membranes by photocuring thin layers of HIPEs to increase their external surface and promote interaction with light. Photobleaching tests show the ability of these materials to generate bactericidal singlet oxygen. Antibacterial tests also demonstrate the sustained antibacterial efficacy of the QMA-based porous membranes, providing a promising avenue for the development of next-generation antibacterial materials.

Recent Trends in Tailoring External Acidity in Zeolites for Catalysis.

Zeolites are crystalline aluminosilicates with well-defined microporous structures that have found several applications in catalysis. In recent years, great effort has been devoted to defining strategies aimed at tuning structural and acidity properties to improve the catalytic performance of zeolites. Depending on the zeolitic structure, the acid sites located inside the crystals catalyze reactions by exploiting the internal channel shape-selectivity. In contrast, strong acid sites located on the external surface do not offer the possibility to control the size of molecules involved in the reactions. This aspect generally leads to a loss of selectivity toward desired products and to the uncontrolled production of coke. Passivating surface acidity is a promising way to overcome deactivation issues and to enhance the catalytic performance of zeolites. This Mini-Review aims to provide, for the first time, a complete overview of the techniques employed in recent years to neutralize strong external acid sites. Both chemical and liquid vapor deposition of silicates have been widely employed to passivate the external surface acidity of zeolites. In recent years, the epitaxial growth of layers of aluminum-free zeolite, e.g., silicalite-1, over the surface of the acidic zeolite has been proposed as a new approach to neutralize strong external acid sites controlling diffusional phenomena. NH3-TPD, FT-IR, SEM-EDX, and other techniques have been used to provide information about the level of control of the external strong acidity of passivated zeolites. In this Mini-Review, both passivation treatments and characterization techniques are compared and advantages and disadvantages deeply discussed to elucidate the effect of passivation procedures on physical features and especially the catalytic behavior.