Agar Research Articles

P-196. Differences in Clostridioides difficile Molecular Epidemiology and Antimicrobial Susceptibility at Two Veterans Affairs Hospitals

Abstract Background Clostridioides difficile infections (CDI) are caused by a diverse group of strains with differences in prevalence and differing antimicrobial susceptibilities. Over the past 20 years the C. difficile (CD) molecular epidemiology has changed as the prevalence of the epidemic strain recognized as PCR-Ribotype group (RT) 027 has decreased. The objective of this study was to determine the current molecular epidemiology and antimicrobial susceptibility patterns of CD at two Veteran Affairs hospitals.Figure 1.PCR-Ribotyping of Clostridioides difficile isolates collected from the Hines VA and Cleveland VA from 7/2022 - 6/2023 Methods We determined the molecular epidemiology and antimicrobial susceptibility of CD at the Edwards Hines Jr., VA hospital and the Louis Stokes Cleveland VA hospital from 7/2022 – 6/2023 from clinically relevant stool specimens. Available stools were cultured and recovered CD isolates underwent PCR-RT (n=194). In vitro minimum inhibitory concentration (MIC) was determined by agar gel dilution for 9 antibiotics known to precipitate CDI. Geometric mean MIC was compared between hospitals by Wilcoxon rank sum test and Kruskal-Wallis was used to compare MICs across PCR-RT groups. Results From 7/2022 – 6/2023, RT106 was the most prevalent strain accounting for 23.5% (16/68) and 15.1% (19/128) of isolates at the Hines VA and Cleveland VA, respectively. (Figure 1) RT002 and RT014/020 were the next most common strains, while RT027 accounted for only 4.1% (8/194) of all isolates. The Hines VA isolates had a higher geometric mean MIC for cefepime (208.15 µg/ml vs 155.13 µg/ml, p< 0.01), clindamycin (9.91 µg/ml vs 5.3 µg/ml, p< 0.01), and piperacillin/tazobactam (9.46 µg/ml vs 7.36 µg/ml, p=0.03). The Cleveland isolates had a higher doxycycline geometric mean MIC (0.08 µg/ml vs 0.05 µg/ml, p< 0.01). (Table 1) The clindamycin geometric mean MIC was elevated for RT255 (9.33 µg/ml) and RT027 (49.35 µg/ml) when compared to other groups (p< 0.01). The doxycycline geometric mean MIC was elevated for RT078/126 (1.17 µg/ml) when compared to other groups (p< 0.01). (Table 2) Conclusion The once epidemic strain RT027 has been supplanted by three different strain groups at both VA hospitals. Further research is needed to correlate local antibiotic usage patterns with the differing strain prevalence and antimicrobial susceptibilities noted. Disclosures Andrew M. Skinner, MD, BioK plus: Advisor/Consultant|Ferring Pharmaceuticals: Advisor/Consultant|Recursion pharmaceutical: Advisor/Consultant Larry K. Kociolek, MD, MSCI, Merck: Grant/Research Support Curtis Donskey, MD, Clorox: Grant/Research Support|Pfizer: Grant/Research Support Dale N. Gerding, MD, AstraZeneca: Advisor/Consultant|Destiny Pharma: Advisor/Consultant|Destiny Pharma: Licensed IP to Destiny|Sebela: Advisor/Consultant|Sebela: Licensed IP Stuart Johnson, M.D., Acurx Pharmaceuticals: Advisor/Consultant|Bio-K Plus International: Advisor/Consultant|Ferring Phamraceuticals: Advisor/Consultant

Changes in fetal hemoglobin levels in patients with liver cirrhosis with type 2 hepatorenal syndrome and chronic kidney disease

Liver cirrhosis (LC) is highly prevalent in the modern population and is the leading cause of death among all gastrointestinal tract diseases. The course of cirrhosis can be aggravated by a number of conditions that makes the management of patients with this pathology even more challenging. One of these conditions is hepatorenal syndrome (HRS) type 2. This condition is a special form of chronic kidney disease (CKD), in which it is believed that changes in the kidneys are largely functional and reversible. Diagnosis and treatment of HRS type 2 in LC require special approaches.The purpose of the study. To establish possible differences in fetal hemoglobin (HbF) indicators in patients with structural damage to kidney tissue in CKD and renal dysfunction associated with the development of type 2 HRS in patients with LC.Materials and methods. Participants were recruited among patients of the therapeutic and gastroenterological departments of the State Healthcare Institution of the Astrakhan Regional Clinical Hospital in Astrakhan. The study included 40 patients with Child-Pugh B, C LC without signs of HRS, 21 with LC and HRS type 2, 92 with CKD of stages 3, 4, 5, and 43 healthy donors in the control group (CG). HbF analysis was performed by rocket electrophoresis in agar gel with sodium dodecyl sulfate using pure HbF preparations and the author's monospecific antisera to Hb F. Results. To identify additional criteria for the differential diagnosis of HRS type 2 and CKD, a study of the HbF level was conducted in these groups of patients, as well as their comparison by this indicator LC without HRS and CG. The study revealed a statistically significant decrease in HbF in the CKD group compared to patients with LC with type 2 HRS, LC without HRS, and GC.Conclusion. The identified changes allow using quantitative determination of the HbF level for differential diagnostics of organic kidney damage, characteristic of CKD, from renal dysfunction in type 2 HRS in patients with cirrhosis. The presence of CKD in a patient is indicated by a reliable decrease in HbF parameters, compared with the norm, while in cirrhosis with type 2 HRS they exceed normal values.

Exploring Potential of a Remote Plasma Electrolysis System (RPES) for Fruit Surface Sterilization

This study investigates the potential of remote plasma electrolysis systems (RPES) for eliminating microorganisms on fruit surfaces. A plasma electrolysis reactor generated long-lived reactive oxygen and nitrogen species (RONS), including hydrogen peroxide (H2O2), nitrite (NO2-), nitrate (NO3-), nitrous acid (HNO2), and nitric acid (HNO3), which were introduced into a treatment chamber through airflow. The spatial distribution of these reactive species was visualized using a KI-starch agar gel reagent. The antimicrobial efficacy of RPES was tested in vitro against methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli). Following optimization, the system was applied to sterilize 1.0 kg samples of rambutans and grapes, with a treatment time of 10 minutes. After treatment, aerobic bacteria on rambutan surfaces decreased by 98.3%, and yeasts and molds level dropped by 50.1%. On grape surfaces, RPES completely eliminated aerobic bacteria, yeasts, and molds. These findings demonstrate RPES’s effectiveness in inactivating surface pathogens on fruits, highlighting its potential for broader applications in fruit sterilization.

<b>Clinical insights on paratuberculosis in Arabian camels (<i>Camelus dromedarius</i>): A review</b>

Paratuberculosis (PTB) is a long-standing granulomatous infectious disease of both domesticated and wild ruminants. It is caused by Mycobacterium avium subsp. paratuberculosis (MAP). This review emphasizes the clinical, hematobiochemical, sonographic and pathologic findings as well as therapeutic and control measures in dromedary camels infected with PTB. The clinical signs include intermittent and/or chronic diarrhea, decreased milk yield, emaciation, submandibular edema, dehydration, irregular and weak rumen contractions and abdominal pain. Hematological changes include leukocytosis, neutrophilia and decreased erythrocytes, hematocrit percent and hemoglobin concentration. Biochemical alterations included hypoalbuminemia, hypoproteinemia, hyperglobulinemia, hypomagnesemia, hypoglycemia and increased alanine aminotransferase and aspartate aminotransferase activity and increased concentration of magnesium and calcium. Sonographically, the intestinal wall is either mildly, moderately or severely thickened along with mesenteric lymph nodes (LN) enlargement. The LN capsule is either anechoic or echoic and the contents are either echogenic, anechoic or heterogenous. Other sonographic findings include bright hepatic parenchyma, aggregation of echogenic materials separated with fluids among the intestines and pleural and pericardial effusions. The typical pathological lesions are corrugation of the small intestinal mucosa especially that of the ileum, and the colonic mucosa are folded. Mesenteric and ileocecal LNs are edematous, congested and granular. Other necropsy findings include fatty liver, and peritoneal, pericardial and pleural effusions. Histologically, proliferative enteritis and lepromatous granulomas are detected. Clusters of acid-fast bacilli are usually found in the intestinal mucosa and lamina propria. Accurate diagnosis of PTB depends on culture and identification of the causative organism MAP from tissue or feces. Herd screening is also performed through complement fixation, agar gel immunodiffusion, competitive enzyme linked immunosorbent assay, Ziehl-Neelsen staining of tissue or feces, histologic pattern of a granulomatous reaction, DNA probes and polymerase chain reaction. A trial for treatment of PTB in dromedary camels was carried out through IM injection of rifampin and streptomycin for 10 weeks. The diarrhea resolved within one week of treatment, and MAP disappeared from rectal scraping 5-9 weeks after treatment. In conclusion, early detection and eradication procedures of PTB should be more implemented for the control and prevention PTB in dromedary camels. More research should be directed towards vaccination program in those species.

Silica hydrogels as a carbon-free solid media for the culture of diverse organisms.

Bacteriological agar plates are commonly used to carry out experiments for the selective growth of microorganisms and the isolation of single-strain colonies. However, the presence of agar itself may be a confounding factor since it may serve as a source of carbon and energy. Moreover, there have been ongoing constraints on the production and sourcing of agar. These concerns have led to an interest in the development of agar substitutes. Silica hydrogels are entirely inorganic carbon-free polymeric materials that lack any source of micronutrients. Herein, a revised method for the preparation of silica hydrogels as a solid culture medium is reported. These gels can be formulated with a range of nutrient-rich or minimal media supplemented with various carbon sources, and can be manipulated in the same manner as agar gels. Their use for the culture and isolation of diverse microorganisms, including both Gram-positive and Gram-negative bacteria, yeast, and filamentous fungi is demonstrated. These silica hydrogels supplemented with either antibiotics or other molecules of interest can also be used for microbial selection experiments.

POSITIVITY FOR BRUCELLA CANIS IN SERUM FROM DOGS LOCATED IN TERESINA (PI, BRAZIL)

Brucellosis is an infectious, contagious, cosmopolitan disease that affects domestic and wild animals and humans, which is why it is considered a zoonose. Brucellosis has not yet been diagnosed in dogs in Piauí (Brazil). For this reason, a study was carried out with serum from animals of reproductive age in the municipality of Teresina, capital of the State of Piauí (Brazil) with serum from dogs from the routine care of the Veterinary Hospital of the Federal University of Piauí, as well as from private clinics in the said city. Blood was collected from all animals for serological tests to detect anti-Brucella canis antibodies. 591 serum samples from non-castrated animals between one and seven years of age were used, without distinction of sex or breed. The samples were submitted to the serological test of immunodiffusion in agar gel using antigen extracted from the cell wall of Brucella ovis. Among the selected dogs, 44 animals were positive for Brucella canis, which represents a frequency of 7.44%. Most dogs were asymptomatic. Among symptomatic patients, lymphadenopathy was the most frequent finding. It was concluded that Brucellosis is present in the canine population of Teresina, but it has not yet been correctly diagnosed by veterinarians, which puts public health at risk.

Magnetically Controlled Transport of Nanoparticles in Solid Tumor Tissues and Porous Media Using a Tumor-on-a-Chip Format.

This study addresses issues in developing spatially controlled magnetic fields for particle guidance, synthesizing biocompatible and chemically stable MNPs and enhancing their specificity to pathological cells through chemical modifications, developing personalized adjustments, and highlighting the potential of tumor-on-a-chip systems, which can simulate tissue environments and assess drug efficacy and dosage in a controlled setting. The research focused on two MNP types, uncoated magnetite nanoparticles (mMNPs) and carboxymethyl dextran coated superparamagnetic nanoparticles (CD-SPIONs), and evaluated their transport properties in microfluidic systems and porous media. The original uncoated mMNPs of bimodal size distribution and the narrow size distribution of the fractions (23 nm and 106 nm by radii) were demonstrated to agglomerate in magnetically driven microfluidic flow, forming a stable stationary web consisting of magnetic fibers within 30 min. CD-SPIONs were demonstrated to migrate in agar gel with the mean pore size equal to or slightly higher than the particle size. The migration velocity was inversely proportional to the size of particles. No compression of the gel was observed under the magnetic field gradient of 40 T/m. In the brain tissue, particles of sizes 220, 350, 820 nm were not penetrating the tissue, while the compression of tissue was observed. The particles of 95 nm size penetrated the tissue at the edge of the sample, and no compression was observed. For all particles, movement through capillary vessels was observed.

Mucin Promotes Bacterial Swarming by Making the Agar Surface More Slippery.

When inoculated on the surface of soft agar containing nutrients, many species of motile bacteria can grow into a dense population and spread across the surface by a form of motility called swarming. We study the swarming behavior of Enterobacter sp. SM3, a species of bacteria that exhibits a swarm-dependent reduction in symptoms associated with inflammatory bowel disease (IBD). In this report, we focus on how incorporating mucin into agar gels affects the swarming motility of SM3. We found that mucin enhances SM3's swarm rate, defined as the rate at which bacteria cover an agar surface. We show that mucin promotes wetting of aqueous droplets by inhibiting the pinning of the contact line, which is caused by structural or chemical inhomogeneity. This effect results in a more slippery agar surface. As a macromolecular biosurfactant, mucin promotes an increase in the bacterial swarm rate on agar by masking surface inhomogeneities, thereby inhibiting contact line pinning and allowing for better spreading of an expanding bacterial swarm.

Detection of antibodies against H5 subtype highly pathogenic avian influenza viruses in multiple raccoons in Tokachi District, Hokkaido, Japan, from 2022 to 2023.

In recent years, infection cases of H5 subtype highly pathogenic avian influenza viruses (HPAIVs) in wild mammals have increased globally. To obtain recent epidemiological information regarding influenza A virus (IAV) infection in raccoons (Procyon lotor), the prevalence of anti-IAV antibodies in sera was analyzed among raccoons captured in Tokachi District, Hokkaido, Japan, from 2019 to 2023. Screening of serum samples using enzyme-linked immunosorbent assay and agar gel precipitation test detected anti-IAV antibodies in 5 of 114 (4.4%) raccoons. All positive sera were from raccoons captured from 2022 to 2023. The hemagglutination inhibition test revealed that all five serum samples contained anti-H5 subtype HPAIV antibodies, and one also contained anti-H1 subtype antibodies. The neuraminidase inhibition test revealed that all five sera contained anti-N1 subtype antibodies, and one also contained anti-N8 subtype antibodies. In the virus neutralization test, these five sera showed stronger neutralization activity against the H5 subtype clade 2.3.4.4b HPAIV strain recently circulating worldwide compared to the old H5 HPAIV strain isolated in Japan in 2007. Findings suggested that raccoons could be involved in the circulation of H5 HPAIVs in nature.

Field determination of trace concentrations of hazardous metals in waters by portable EDXRF.

A new effective method has been developed for field determination of trace concentrations of cadmium, arsenic, zinc, copper, nickel, chromium, and lead in waters (e.g., surface and wastewater) using an energy dispersive X-ray fluorescence (EDXRF) analyzer. Trace concentrations cannot be determined by EDXRF without preconcentration. Agar was used for the preconcentration of these potentially toxic elements (PTE). Metals are trapped in the three-dimensional network of agar gel. Subsequent swelling of the gel leads to more effective preconcentration. The swollen gels with PTE were analyzed by a portable energy dispersive X-ray fluorescence analyzer Delta Professional X (pXRF). The preconcentration factors for each PTE were determined. With pXRF, the detection limits were 7, 5, 6, 7, 9, 47, and 22 µg/L for Cr, Ni, Cu, Zn, As, Cd, and Pb, respectively. A reference material was used to assess the methodology performance, and it has a very good agreement. The optimized and verified methodology was tested in practice at the special chemical unit of the Fire Rescue Service of the Czech Republic. PTE were determined by pXRF in a mobile chemical laboratory in field analysis. The measured values were compared with those determined via inductively coupled plasma mass spectrometry (ICP-MS) and were in good agreement. Our method was applied to real wastewater samples collected during after a fire of accumulation batteries of domestic photovoltaic power plants, allowing accurate real-time estimation of PTE concentrations. Obtaining reliable data during an ecological accident has a very important role in minimizing the subsequent environmental impact of the accident.

Dyadobacter helix sp. nov. and Dyadobacter linearis sp. nov., from drinking water.

The purpose of this study is to better characterize and complete the classification of two bacterial strains, CECT 9275T and CECT 9623T, isolated from drinking water systems and affiliated to the genus Dyadobacter by partial 16S rRNA gene sequence comparison. Hence, we report here the phenotypic, genomic and phylogenetic characterization performed on these strains. Both strains grow on R2A agar forming mucous, bright yellow colonies, developing at 26 °C in 48 h. They produce flexirubin and are oxidase and catalase positive, mesophilic and non-halophilic. The cells of strain CECT 9275T are curved rods mainly associated in pairs, forming nearly closed rings or resembling the shape of the number three, to long spirals resembling a corkscrew. Its draft genome has an estimated size of 7.23 Mbp (G+C content 45.4%). Strain CECT 9623T appeared on wet mounts as straight rods, mostly in pairs, sometimes forming long filaments (up to 20 µm). Its draft genome is shorter, with an estimated size of 6.45 Mbp (G+C content is 46.1%). Overall genome relatedness indexes clearly define them as separate organisms, so based on all the data collected, we propose the species Dyadobacter helix sp. nov. with type strain AB1T (=CECT 9275T=LMG 32341T) and Dyadobacter linearis sp. nov. with type strain AB67T (=CECT 9623T=LMG 32342T).

A Non-Prescription Nitric Oxide Releasing Gel Demonstrates In Vitro Anti-fungal Activity and Supports Nail Clearance in Patients with Onychomycosis

Background: Onychomycosis is a common fungal nail infection. Nitric oxide has broad-spectrum antifungal activity; NO releasing formulations are in development to support nail wellness. Objective: to examine antifungal properties of NO releasing formulations liquid (NORS) and gel (NORS-gel) to support nail clearance in onychomycosis. Methods: NORS In Vitro antifungal testing: Minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) were used to compare NORS with efinaconazole. Trichophyton tonsurans, Trichophyton mentagrophytes, and Epidermophyton floccosum were selected and MFC was performed. Cidal activity: ≥ 99.9% reduction in CFUs/mL from baseline; Static activity: <99.9% reduction from baseline CFU/mL. (CFU: colony forming units). NORS keratin binding: Six tubes were prepared with 1 mL + 107 conidia/mL of T. mentagrophytes strain (37035) + sterilized cadaver nail; six treatment tubes included: NORS, NORS+Keratin (50mg/mL), Terbinafine (0.002 µg/mL)+keratin (50 mg/mL), Terbinafine (0.002 µg/mL), Growth control (T. mentagrophytes+saline). After 15-min, tubes were centrifuged, supernatant decanted, and pellets resuspended in sterile saline; 10-fold serial dilutions were plated (triplicate). Ex-Vivo in Onychomycosis: Toenail samples from patients with suspected onychomycosis were shredded and either placed onto agar plates incubated at 30°C for 1-month, or, treated with 1.5mL NORS-gel to 50mL tube, placing the clippings onto the gel and then overlaying another 1.5mL NORS-gel, samples were stored in the dark at room temperature for 8-hours, washed, dried, plated and incubated at 25°Cx7days Nail penetration: Underside of cadaver toenails were inoculated with T. mentagrophytes 107 conidia/mL and placed on inert gel agar. A bead of NORS-gel (approx. 0.125mL), control gel and Terbinafine 0.002 µg/mL were spread to cover the topside of the nail. Covered petri dishes were placed for 15-minutes and 8-hours; the nail was removed, washed 3x in sterile saline, and pulverized; serial dilutions with plated samples incubated at 25°Cx7days. Statistics: Log CFU ± standard deviation, analyzed by t-test, p ≤ 0.05. Human Volunteers: Three individuals with confirmed onychomycosis applied daily NORS-gel to infected nails (covered overnight), for one month. Photographs were taken at baseline, day 1 after application, and 4-5 months post-application. Volunteers self-reported nail appearance. Results: NORS In Vitro antifungal testing: NORS showed potent antifungal activity against dermatophytes, including those less susceptible to efinaconazole. NORS keratin binding: NORS with and without keratin demonstrated the lowest fungal burdens with average log CFUs/mL ± SD of 0 ± 0, and 2.45 ± 0.5, respectively, demonstrating significant activity vs control, and terbinafine (P-values < 0.0001). Ex Vivo: NORS-gel demonstrated significant fungicidal activity as indicated by the absence of fungal growth on petri dishes. Nail penetration: NORS-gel treated nail showed no fungal growth (average log CFUs/g ± SD of 0 ± 0) vs. terbinafine–burden of 3.58 ± 0.2 average log CFU/g, at 8 hrs. NORS-gel significantly reduced fungal burden vs. terbinafine and control (P-value < 0.05). (preliminary results; methodology undergoing refinement.) Human Volunteers: Daily application of NORS-gel for one-month improved nail clarity in volunteers with confirmed onychomycosis. Temporary discoloration was observed during treatment. Conclusions: NORS and NORS-gel demonstrated antifungal activity; NORS-gel supported nail clearance and was well tolerated in individuals with onychomycosis.

A high-performance flexible biopolymer-based Ce oxide composite electrolyte for lithium-ion battery dendrite reduction

We propose a novel solid-state composite polymer electrolyte (CPE) that includes Li7La2.5Ce0.5Zr2O12 (Ce-LLZO), chitosan (CS)/agar-agar (AA) polymer, polyethylene glycol (PEG) plasticizer, and LiClO4 salt. At 25 °C, the CPE3 formulation, consisting of 15 wt% Ce-LLZO, 60 wt% CS-AA, 15 wt% PEG, and 10 wt% LiClO4, demonstrated exceptional lithium (Li)-ion conductivity of 5.18 × 10-3 S cm−1 and an optimal transference number (TLi+) of 0.937. We assessed the electrochemical stability of CPE3 using linear sweep voltammetry, which revealed a maximum stability limit of 4.1 V (versus Li/Li+). In addition, the coin cell made with the Li||CPE3||NMC configuration had an amazing discharge capacity of 163 mAhg-1 and stayed stable for up to 100 cycles at 0.1 °C in room temperature. Conversely, when subjected to Li-plating/stripping cycles, the symmetric Li||CPE3||Li cell exhibited stability for 550 h and maintained a current density of 2.0 mA cm−2. Compared to Li-metal, the proposed material exhibited reduced overpotential while simultaneously enhancing electrochemical stability.

DIFFERENTIATED IN VITRO LYSOZYME ACTIVITY IN AVES AND MAMMALIA IN RESPONSE TO SEABUCKTHORN (HIPPOPHAE RHAMNOIDES) STIMULATION

Lysozyme, an intrinsic component of the immune system, is a naturally occurring enzyme with antimicrobial activity (Khorshidian et al., 2022), by hydrolyzing the muramyl dipeptide in the bacteria cell wall. Considered to be an endogenous antibiotic, it differs by species (Ferraboschi et al., 2021). Some of the medicinal plants were cited to inhibit the anti-lysozyme activity and biofilm formation by bacteria (Bukharin et al., 2003). The aim of this research was to evaluate the differences in the in vitro activity of lysozyme between the classes Aves and Mammalia when treated with a protein-carotenoid extract of Hypopphae rhamnoides compared to well-known immune modulating preparations (selenium or selenium and copper compounds). The investigations were carried out on serum samples from: a) commercial broiler chickens aged 34 days (n = 19) and b) 5-month-old Supercunirom breed male rabbits (n = 19). The agar gel radial immune diffusion method and the Micrococcus lysodeicticus test strain were used to define the in vitro lysozyme activity. The sera were mixed with serial dilutions (1:2, 1:4, etc.) of the tested compounds. The groups were compared by Student’s t test for statistical significance of the results. He increase in activity (%) versus control were calculated. Sea buckthorn extract significantly (t= 7.22, p < 0.001) decreased the in vitro activity of lysozyme at both dilutions used (1:2, 1:4). The concentration of serum lysozyme was higher in rabbits than in chickens and its lytic activity was enhanced by selenium and copper combinations in chickens (183.69 ± 37.91%) and less in rabbits (128.45 ± 84.10%) in a dose dependent manner. At lower dilutions (3:4), the lysozyme activity remained below that of the control treated with saline. The protein-carotenoid extract of sea buckthorn acted inhibiting on lysozyme activity, proving the need for tailored extraction and treatment protocols depending on the bacteria and host species.

Improvement of Adsorption Capacity by Refined Encapsulating Method of Activated Carbon into the Hollow-Type Spherical Bacterial Cellulose Gels for Oral Absorbent.

To reduce the risk of adsorption of granular activated carbon (AC) in the gastrointestinal tract, we successfully prepared a hollow-type spherical bacterial cellulose gel encapsulated with AC (ACEG) and evaluated its pH tolerance and adsorption capacity. The bacterial cellulose gel membrane of ACEG features a three-dimensional mesh structure of cellulose fibers, allowing the selective permeation of substances based on their size. In this study, the preparation method of ACEGs was investigated, and the indole saturation adsorption capacity of the obtained gel was measured. We modified the gel culture nucleus gel from calcium alginate gel to agar gel, facilitating the encapsulation of previously challenging particles. The new preparation method used sodium hydroxide solution for sterilization and dissolution to remove the debris of Komagataeibacter xylinus, which was feared to remain in the bacterial cellulose membrane. This treatment was also confirmed to have no effect on the adsorption capacity of the AC powder. Therefore, this new preparation method is expected not only to improve the performance of ACEGs but also to be applied to a wide range of adsorbent-encapsulated hollow-type bacterial cellulose gels.

A modular, human body-mimicking phantom with active thermoregulation capabilities for validation and verification of convective hyperthermia devices

Objectives This study aims to design and fabricate a modular phantom for hyperthermia applications, addressing interpatient variability in thermal regulation mechanisms like sweating rate, metabolic heat production, and blood redistribution. Materials & methods The phantom can be constructed in various weights and dimensions by connecting identical units. Each unit consists of an agar-based block, an ethyl cellulose-based top layer, a heat source, deep and superficial water circulation, and a sweating mechanism. Agar and ethyl cellulose gels mimic the thermal properties of human tissues and fat respectively. The blocks are wrapped in PVC foil to prevent water evaporation. A heating wire, coiled around an embedded aluminum tubing simulates metabolic heat production. A superficial water circulation mimics skin capillaries. A water pump ensures a steady flow rate throughout the tubing system. Sweat production is simulated using a water pump and perforated tubing. A programmed controller maintains core temperature in a normal operating mode and simulates an anesthetized patient in anesthesia mode. Results Temperature uniformity and regulation were assessed under varying environmental conditions. The phantom effectively regulated its core temperature at 37.0 °C +/- 0.7 °C with an ambient temperature ranging between 21 °C and 30 °C. Activating the water circulation reduced the maximum temperature gradient within the phantom from 4.70 °C to 1.92 °C. Conclusion The versatile phantom successfully models heat exchange processes. Its thermal properties, dimensions, and heat exchange rates can be tuned to mimic different patient models. These are promising results as an effective tool for hyperthermia device validation and verification, representing human physiological responses.

Gel Cleaning in Heritage: Comparison of the Water Release among Gels and Traditional Pads.

Water release is a crucial aspect when considering cleaning effects on water-sensitive materials. In conservation practice, a water-based cleaning method which limits water release is very often needed. Unfortunately, this is not accompanied by an appropriate measure of the effectively released water. In this paper, water release has been measured by comparing traditional cleaning formulations, such as paper pulp and sepiolite, with several gar gel formulations, used by both Italian and European conservators. The assessment has been carried out by the gravimetric method, using three different stone material specimens as reference: Noto calcarenite, Manciano sandstone and Black Bergamo limestone, whose porosity values and distributions are known. Moreover, water distribution has been evaluated by portable NMR tests. Different commercial agar gel products (Bresciani, CTS, Sigma), having different concentrations (3, 4, and 5%), application modes (rigid at room T or fluid warm gels, with and without inserting Japanese tissue paper), and geometry (horizontal in gravity force direction or vertical), have been compared to obtain a full scenario among different water release mechanisms present in real conservation works. The paper faces the important issue of preparing reproducible chemical or water pads as well, useful for further research aimed at comparing cleaning effects in heritage conservation. The most interesting quantitative results can be summarized as follows. The water release measured from paper pulp and sepiolite was found to be 2 to 4 times higher than from any tested agar gel. Water release decreases by increasing agar concentration; an increase in the agar concentration by 1% induces a decrease in water release in the range 16.98-66.88 g depending on the stone; the increase from 4% to 5% is more obvious with respect to that from 3% to 4%. It is possible to assess the effect of the presence of Japanese paper, which is able to reduce the water release from 18 to 76%, depending on the stone and on the agar used. The gravimetric results were also used in the preliminary calibration tests of a contact probe named System Unit Salinity Index (SUSI), recently patented and useful in providing humidity and salinity indexes in a given porous material.

Magnetoactive elastomer-based dynamic urethral support device for stress urinary incontinence

Stress urinary incontinence (SUI) is the involuntary leakage of urine in response to increased intra-abdominal pressure during episodes of exertion. A common treatment method for SUI is sling implantation underneath the urethra to provide support. Most current sling procedures, however, cannot adjust urethral tension postoperatively. To address this limitation, we designed a soft magnetoactive elastomer (MAE) device capable of changing shape in response to moderate magnetic fields. To ensure shape change after fibrotic scar tissue encapsulation, MAE devices were embedded in agar gels with different stiffnesses, and their shape change was studied in response to up to 200 mT magnetic fields. A simple in vitro model of the lower urinary tract was designed to study device performance. Flow time was measured as a function of pressure in the simulated bladder as the model system leaked before and after activating sling with a hand-held magnet. MAE devices embedded in agar gel (100 kPa) in hammock-like configuration achieved 4.7% ± 1.1% change in height. Devices with silica-coated magnetic particles showed minimal loss in mass after two weeks in accelerated oxidative (2.36% ± 1.55%) and hydrolytic (0.58% ± 0.25%) conditions. Placing a sling under the model urethra provided urethral support; thus, increasing its resistance to flow. Normalized flow time significantly reduced from 1.56 ± 0.18 to 1.11 ± 0.16 when magnetic field was applied, indicating urethral support modulation at 60 cm-H2O. This dynamic sling, powered externally with physiologically safe magnetic fields, allowed for urethral support modulation in a model of the lower urinary tract. Statement of significanceStress urinary incontinence (SUI) affects up to half the adult women during their lifetime, and slings are commonly used to treat severe cases. While sling implantation is minimally invasive and offers moderate to high cure rates, long-term sling complications, such as urine retention, remain a significant concern. Available adjustable SUI devices often require invasive surgeries, implantable electronics, and multiple mechanical components, increasing the overall invasiveness. Here, we report a proof of concept for using shape-morphing biomaterials to fabricate a dynamic device that can provide continence support and be triggered to change shape, enabling complete voiding. Such a dynamic device may prevent many complications associated with traditional slings and improve quality of life for women suffering from severe SUI.

Biotoxicity Evaluation of Biodegradable Polymeric Particles: Exploring the Possible Adverse Impacts on Biological Systems

ABSTRACTThis study aimed to investigate the impact of plastic particles on cell viability and tissue toxicity. The cells were subjected to incubation with plastic particles immobilized in agar gels, resulting in minimal cell death and cytotoxicity. Furthermore, direct exposure of various cell types to suspended plastic particles showed negligible effects on cell viability, with no observed lysis or growth inhibition. Staining techniques revealed minimal plastic particle‐induced cell death, with the majority of cells remaining viable. However, histological evaluations of mouse tissues demonstrated that the nondegradable low‐density poly(ethylene) (LDPE) groups exhibited severe irritation, characterized by an excessive presence of macrophages, neutrophils, fibrosis, fat infiltration, and increased blood vessel formation in subcutaneous tissue. In contrast, biodegradable neat poly(butylene succinate) (KRICT‐PBS) and cellulose nanocrystals/PBS nanocomposite (CNC‐PBS) groups induced minimal toxicity. Interestingly, the intravenous injection of KRICT‐PBS and CNC‐PBS degradate solutions in mice exhibited mild toxicity, suggesting no significant damage to normal kidney and liver function.

Make it a standard? The creation and variability assessment of a consensus standard protocol for Tenebrio molitor larvae feeding trials

Abstract Interest in the nutrition of the yellow mealworm (Tenebrio molitor L.) larvae is on the rise, leading to an increase in publications on this topic. The absence of a standard protocol and resulting differences in experimental designs reduces comparability among studies and impedes research on mealworm nutrition. To address this, a consensus standardised protocol was developed specifically for the evaluation of mealworm larval growth and performance in feeding trials. The efficacy of this protocol was evaluated through an international ring test involving seven partners using two wheat brans as dry feed (a standard bran and a local bran) at 27 °C and 60% relative humidity. As experimental units, plastic crates filled with 2.1 kg of bran and 10,000 4-week-old larvae were used with six replicates. Agar gel was provided as wet feed ad libitum. The mean individual larval weight and the number of larvae per crate were determined weekly until either three or more replicates ran out of feed or pupation exceeded 10%. At harvest, the total larval fresh biomass and amount of frass was determined. Larval samples were taken for chemical analysis. To assess the protocol, the within (repeatability) and between (reproducibility) laboratory variability was calculated for each parameter. The repeatability was good (limit at 12% (standard) and 14% (local)). The reproducibility was poorer with a limit 2.7 times higher for the standard feed (36%) and 3.8 times higher for the local feed (55%). For both feeds, the total larval fresh harvest, amount of frass and the larval protein concentration were the most consistent both within and among laboratories. The highest variability was observed at the early life stages and for the larvae ash content. The detailed consensus standard protocol and repeatability/reproducibility estimates can be used as basis for future mealworm feeding trials, comparing results and future improvements.