Thermoresponsive electrospun scaffolds based on poly(N-isopropylacrylamide) (PNIPAM) copolymers exhibit morphology-dependent structural disintegration upon cooling to the temperature of the coil-to-globule transition. This behavior does not coincide directly with the classical lower critical solution temperature (LCST) or volume phase transition temperature (VPTT) due to the specific fiber architecture formed by electrospinning. In this study, the Scaffold Disintegration Temperature (SDT) is introduced as an operational descriptor corresponding to the onset of reproducible morphological collapse in fibrous PNIPAM networks. SDT is used as a comparative metric to assess how the macromolecular architecture and processing conditions relate to the scaffold-level stability. Using viscosity-matched statistical and graft copolymers with distinct topologies, architecture-dependent differences in the disintegration behavior were identified. These differences correlate with variations in network morphology and orientational coherence. Scaffolds based on graft copolymers bearing rigid (PLA) or flexible (PCL) side chains exhibited earlier structural disintegration during cooling and reduced network coherence, whereas the statistical P(NIPAM-co-NtBA) system maintained structural integrity over a broader temperature interval and showed greater mechanical robustness under comparable conditions. A variation of the nozzle-to-collector distance further modulated the architecture-dependent differences in the fiber morphology, porosity, and mechanical performance but did not override the dominant influence of macromolecular topology. These results establish SDT as a network-level, morphology-dependent parameter that complements LCST in describing the thermal behavior of electrospun PNIPAM-based materials.

This study examines the local transmission of normal and pathological corneal tissues when exposed to coherent collimated near-infrared (NIR) radiation with a wavelength of 1061 nm, highlighting its potential advantages over ultraviolet (UV) radiation for antimicrobial photodynamic therapy (PDT). The proposed measurement method, which employs an original experimental setup with a collimated NIR laser source and a probe fiber for direct layer-by-layer depth profiling, allows for determining the transmission values at specific depths within the cornea. Considering that the affected areas are localized within 1/3 to 1/2 of the corneal thickness, the residual power of the NIR radiation in the posterior part of the affected zone (at a depth of 250-400 µm) does not exceed 20%. However, the residual power of the NIR radiation at the posterior epithelium of the affected cornea, after passing through its entire thickness, does not exceed 10%. Current UV-based antimicrobial corneal PDT suffers from limited depth penetration and low specificity, hindering effective treatment and requiring photoprotectors to shield the non-regenerating posterior epithelium. NIR-based PDT, using selective photosensitizers, offers a promising alternative. The results of our NIR corneal transmittance measurements are crucial for the development of more targeted, effective, and safer therapies.

Multicellular structures, including cell sheets, are actively used as model systems to study intercellular interactions and can be applied in different areas of regenerative medicine. In this paper, we present a novel approach for measuring mechanical properties of cell sheets based on a simple experimental setup and numerical simulations. The advantage of the present approach is the relative ease of the sample preparation, while previous systems for the tensile tests required specialized and sensitive equipment. With the developed approach, the cell sheet on a polymer membrane is mounted in the holder on one side, and then deflection of the free end of the membrane is measured. The deflection of this cantilever-like construction depends on the elastic modulus of the membrane (which is known) and cell sheet, and also from the traction force generated by the cell sheet. By involving an experimental step with relaxing the traction force and by conducting finite element simulations, both traction force and elastic properties of the cell sheet can be estimated. We performed such measurements on cell sheets from keratocytes from corneal explants and confirmed that the developed approach is applicable for measurement of both traction force and elastic modulus of cell sheets.

A significant (up to 4 times) photoluminescence enhancement of single InP/InAsP/InP nanowires transferred onto a silicon oxide-covered silver layer on silicon substrate with a metal surface roughness level of less than 1 nm and a dielectric thickness of 5 nm has been demonstrated. This phenomenon is explained by the interaction of electron-hole pairs in the semiconductor with surface plasmon polaritons. The photoluminescence kinetics and results of modeling confirm the indicated enhancement mechanism.

This review compares data from scientific studies on the microbial community of the ocular surface (OS) in conditionally healthy individuals using cultural methods (including culture-dependent diagnostic tests), microscopic and molecular genetic methods, and assesses the influence of research methods and sample preparation on the results. Concordance and discordance of the sets of identified microorganisms were analyzed using overlapping and non-overlapping methods of studying the microbial community of a healthy OS. The article presents tables showing the names of microorganisms that were identified in different sources. Cross-verification in taxa of different ranks helped confirm the following most frequently found microorganisms on healthy OS: coccomorphic microorganisms of the genera Staphylococcus, Micrococcus, Kocuria, Streptococcus, Enterococcus; gram-positive spore-forming bacilli of the genera Bacillus and Paenibacillus; gram-positive non-spore-forming rod-shaped bacteria, including Corynebacterium, but excluding Propionibacterium and Microbacterium; gram-negative non-spore-forming rod-shaped microorganisms of the genera Moraxella and Serratia. The study also assessed the effect of wearing soft contact lenses on the composition of the microbial community of the OS.

Viscoelastic hydrogels based on animal tissue extracts are considered promising biomimetics of the extracellular matrix (ECM) due to their proven effectiveness for stimulating the regeneration of the liver, pancreas and articular cartilage. Cryostructuring is an approach that makes it possible to give polymer scaffolds macroporosity and provide mechanical strength. preparation of a new macroporous cryogenically structured biomimetic of ECM based on a commercially available concentrated collagen-containing solution and evaluation of the possibilities of its application in tissue engineering. The target spongy collagen-containing material was obtained by sequential freezing of a concentrated collagen-containing solution, its subsequent lyophilization and chemical tanning by treatment with an alcohol solution of carbodiimide. The morphology of the cryostructured multicomponent collagen-containing material was studied using optical and scanning electron microscopy (SEM) using lanthanide contrast. The cytotoxicity of the scaffold was studied on the culture of human adipose-derived stem cells (hADSCs). Adhesion and proliferation of hADSCs on the scaffold surface were studied on the 7th day of cultivation. The compression modulus of elasticity of the obtained collagen–containing material in the swollen state in water was 35,3 ± 2,2 kPa, the total water-holding capacity of the material was 45.80 ± 0.46 ml/g of polymer, and the degree of swelling of the walls of macropores was 3.99 ± 0.31 ml/g. During SEM examination and histological staining with hematoxylin and eosin, a broad-pored structure was observed on the surface and cross-section of the disc. The pores in the upper part are larger (the average diameter is not less than ~ 30 µm) than the pores in the lower part of the sponge (the average diameter is not more than ~ 30 µm) due to the occurrence of a vertical temperature gradient. The matrix did not have cytotoxicity relative to the hADSCs. In the sample, active proliferation of hADSCs was observed on the surface of the scaffold. It was shown that the developed cryostructurates based on a concentrated collagen-containing solution had supermacroporosity and a compression modulus of elasticity of 35.3 ± 2.2 kPa. The absence of cytotoxicity and the ability to maintain adhesion and proliferation of hADSCs indicate the possibility of using cryogenically structured biomimetic of the extracellular matrix in tissue engineering and regenerative medicine.

PURPOSE. To explore the potential for predicting the hypotensive effectiveness of glaucoma surgeries based on the parameters of the filtering bleb (FB) measured using optical coherence tomography (OCT).METHODS. The study included 15 patients (15 eyes) with uncontrolled primary open-angle glaucoma, who underwent standard glaucoma surgery: sinus trabeculectomy with basal iridectomy. Objective assessment of the FB was performed using OCT on postoperative day 2, and then at 7 days, 1 month, and 3 months after surgery. Based on the OCT scans, a three-dimensional model of the FB was constructed, and its volume was calculated.RESULTS. In 3 patients, by the end of the observation period, the FB volume was less than 5.7 mm³, which was associated with an unsuccessful surgical outcome and an increase in intraocular pressure (IOP) to 22.1±3.2 mm Hg. These patients were prescribed hypotensive therapy to achieve target IOP levels. In the other 12 patients, the IOP remained below 14 mm Hg throughout the observation period, with an average IOP of 11.7±2.3 mm Hg. The FB in these patients was diffuse, and its volume exceeded 5.7 mm³. The successful outcome of the surgery allowed for these patients to avoid the need for additional hypotensive therapy.CONCLUSION. Long-term success of glaucoma surgery can be predicted using the threshold filtering bleb volume of 5.7 mm³.

Poly(vinyl alcohol) (PVA) physical cryogels that contained the additives of o-, m-, and p-bis-phenols or phenol were prepared, and their physico-chemical characteristics and macroporous morphology and the solute release dynamics were evaluated. These phenolic additives caused changes in the viscosity of initial PVA solutions before their freeze–thaw processing and facilitated the growth in the rigidity of the resultant cryogels, while their heat endurance decreased. The magnitude of the effects depended on the interposition of phenolic hydroxyls in the molecules of the used additives and was stipulated by their H-bonding with PVA OH-groups. Subsequent rinsing of such “primary” cryogels with pure water led to the lowering of their rigidity. The average size of macropores inside these heterophase gels also depended on the additive type. It was found also that the release of phenolic substances from the additive-containing cryogels occurred via virtually a free diffusion mechanism; therefore, drug delivery systems such as PVA cryogels loaded with either pyrocatechol, resorcinol, hydroquinone, or phenol, upon the in vitro agar diffusion tests, exhibited antibacterial activity typical of these phenols. The promising biomedical potential of the studied nanocomposite gel materials is supposed.

BACKGROUND: Frequent early postoperative complication of hemorrhoidectomy is thrombosis and edema of mucocutaneous “bridges.” OBJECTIVE: We investigated the efficacy of micronized purified flavonoid fraction in preventing complications following elective hemorrhoidectomy. DESIGN: Prospective unicentral open-label randomized controlled trial. SETTINGS: 2021-2022 Clinic of Colorectal and Minimally Invasive Surgery Sechenov University (Moscow, Russia). PATIENTS: Patients after hemorrhoidectomy, which was done for grade III-IV hemorrhoids INTERVENTIONS: After hemorrhoidectomy, patients were randomly allocated either to standard treatment (peroral non-steroid anti-inflammatory drugs and local anesthetics, topical steroids, psyllium, warm sitz baths, nifedipine gel) – control group, or to standard treatment with micronized purified flavonoid fraction (study group) and followed for 60 days. MAIN OUTCOME MEASURES: Thrombosis or edema of mucocutaneous bridges and pain intensity on a visual analogue scale оn 1st-7th, 14th , 21st and 30th postoperative day; quality of life and patient-assessed treatment effect оn 1st, 3rd, 7th, 21st and 30th postoperative day; perianal skin tags оn 60th postoperative day. RESULTS: The data from 50 patients were analyzed (25 in each group). Visual analogue scale demonstrated nо differences between groups in each follow-up point. Compared to control group, the patients in study group had significantly higher patient-assessed treatment effect оn 1st, 3rd, 7th, 21st and 30th post operative days, significantly lower rate of thrombosis or edema of mucocutaneous bridges оn 1st-7th, and 14th days. Patients in the study group had significantly lower rates of perianal skin tags. LIMITATIONS: Unicenter open-label design. CONCLUSIONS: Micronized purified flavonoid fraction in the post-hemorrhoidectomy period is an effective adjunct to standard treatment that helps reduce the rate of thrombosis and edema of mucocutaneous bridges, improves patient-assessed treatment effect, and prevents postoperative perianal skin tags formation. Micronized purified flavonoid fraction in the post-hemorrhoidectomy period is not associated with additional pain relief in comparison with non-micronized purified flavonoid fraction standard treatment. See Video Abstract .

A new occurrence of phosphate mineralization – named Shankinka – has been explored in the mouth of the Fed’kovskaya river in the Ruza District of the Moscow region, of which, the most common mineral phases include delvauxite, mitridatite, fluorapatite and crandallite. It has been established that all the Fe-Ca-Al phosphates occurrences in the region are associated with the Bajocian-Bathonian paleovalleys embedded in the Carboniferous rocks and partially filled with Callovian sediments. The structural features of the phosphatization zone as well as its enrichment with Co, Ni, Zn, Cu, and REE indicate a possible link between the Oxfordian organic-rich sediment and phosphate mineralization. It can be assumed that epigenetic phosphate mineralization was a result of the seepage of phosphorus-rich pore waters released from the Oxfordian organic-rich sediment into the underlying Callovian permeable rocks rich in iron minerals.

Standard bacteriological examinations, which involve culturing microorganisms at 37 °C, are commonly used in clinical practice for diagnosing infectious diseases. However, the growth temperature of microorganisms on the ocular surface (OS) during infectious keratitis (IK) may not coincide with the laboratory standard, which is due to the characteristic features of heat exchange in the eye. PURPOSE:This exploratory study examines the distribution and properties of OS microorganisms isolated under different temperature cultivation conditions in patients with IK and healthy volunteers without ophthalmic pathology. MATERIAL AND METHODS:Fifteen participants were divided into two groups. Group 1 (n=10) consisted of patients with signs of unilateral infectious keratitis, while group 2 (n=5) served as the control group. A novel microbiological method was employed to isolate pure cultures of microorganisms. This method involved cultivating microorganisms at two temperature regimes (37 °C and 24 °C) and subsequently identifying them using biochemical, immunological, and physicochemical techniques, including mass spectrometry. Scanning electron microscopy (SEM) with lanthanide staining used as the reference method. The temperature status of the ocular surface was assessed using non-contact infrared thermography. RESULTS:The study demonstrated the presence of psychrotolerant microorganisms on the ocular surface, which exhibited growth at a relatively low temperature of 24 °C. These psychrotolerant microorganisms were found to be isolated from the ocular surface displaying signs of temperature dysregulation. Among such microorganisms are Acinetobacter lwoffii, Achromobacter xylosoxidans, Bacillus licheniformis, Enterococcus faecalis, Klebsiella oxytoca, Klebsiella pneumoniae, Micrococcus luteus, Pseudomonas luteola, Streptococcus spp. CONCLUSION:When identifying the causative agent of infectious keratitis, it is crucial to consider the divergence of growth temperature of ocular surface microorganisms. The presence of psychrotolerant microorganisms on the ocular surface, which can effectively grow at room temperature, should be taken into account, especially in cases of temperature dysregulation.

Purpose. To demonstrate the possibility of using electron microscopy in the diagnosis of chronic postoperative endophthalmitis of fungal etiology using a clinical example. Material and methods. A clinical case of chronic postoperative endophthalmitis of fungal etiology is presented in the diagnosis of which light electron microscopy (SEM) was crucial. Results and discussion. The correct diagnosis of fungal chronic endophthalmitis was achieved based on the results of SEM, after which etiotropic treatment was prescribed with a positive clinical result. Conclusion. SEM can act as an additional method for diagnosing chronic postoperative endophthalmitis. Keywords: vitrectomy, endophthalmitis, intravitreal injection of antibiotics, electron microscopy, bacteriological examination

A comprehensive understanding of intercellular and cell-matrix interactions is essential for advancing our knowledge of cell biology. Existing techniques, such as fluorescence microscopy and electron microscopy, face limitations in resolution and sample preparation. Supravital lanthanoid staining provides new opportunities for detailed visualization of cellular metabolism and intercellular interactions. This study aims to describe the structure, elemental chemical, and probable origin of zones of extreme lanthanoid (neodymium) accumulation that form during preparation for scanning electron microscopy (SEM) analysis in corneal fibroblasts filopodia. The results identified three morphological patterns of neodymium staining in fibroblast filopodia, each exhibiting asymmetric staining within a thin, sharp, and extremely bright barrier zone, located perpendicular to the filopodia axis. Semi-quantitative chemical analyses showed neodymium-labeled non-linear phosphorus distribution within filopodia, potentially indicating varying phosphate anion concentrations and extreme phosphate accumulation at a physical or physicochemical barrier. Phosphorus zones labeled with neodymium did not correspond to mitochondrial clusters. During apoptosis, the number of filopodia with extreme and asymmetric phosphorus accumulation increases. Supravital lanthanoid staining coupled with SEM allows detailed visualization of intercellular and cell-matrix interactions with high contrast and resolution. These results enhance our understanding of phosphate anion accumulation and transfer mechanisms in cells under normal conditions and during apoptosis.

The thermal conductivity of natural monoliths of calcite, dolomite marble, and limestone from various deposits was measured using the absolute stationary method of longitudinal heat flow in the temperature range of 50–300 K and the dynamic method in the range of 323–573 K. A majority of calcite marbles were inferior in thermal conductivity to dolomite marbles. At room temperature, the thermal conductivity coefficients of all studied samples were lower k = 5 W/(m K). The obtained data were compared with the literature data. The diversity of experimental data from different authors on the thermal conductivity of carbonates is associated with qualitative differences in the samples studied

To assess the dynamic viscosity of the lacrimal sac wall in patients with various origins of lacrimal duct obstruction. The study was performed in 35 cases: 21 cases with primary nasolacrimal duct obstruction (PANDO) and 14 cases with secondary nasolacrimal duct obstruction after radioiodine therapy (SALDO). The study of biomechanical properties of the lacrimal sac was carried out using a test bench. The principle of the study was to indent the sample at a given speed and record the data obtained from the sensor of the force transmitted to the sample. The area under the curve (AUC) and the peak viscosity were calculated. A qualitative characteristic of the obtained curve was given. Median AUC in patients with PANDO was 17 × 106 [6 × 106; 19 × 106] N/m2 × s, in patients with SALDO 21 × 106 [13 × 106; 25 × 106] N/m2 × s. Intergroup differences were statistically significant (p = 0,048). The median peak viscosity in PANDO patients was 29 × 106 [25 × 106; 35 × 106] N/m2, in patients with SALDO 32 × 106 [21 × 106; 41 × 106] N/m2. The qualitative characteristics of the obtained curves differed. Biomechanical properties of the lacrimal sac may vary depending on the cause of obliteration of the lacrimal ducts. The integrated dynamic viscosity is significantly higher in SALDO patients due to exposure to radioiodine compared to that in PANDO patients.

Factors influencing the geochemical migration of elements during the development of artificial phytocenoses on industrially polluted peat soil with a high level of copper and nickel content using serpentine-containing materials are considered. Monitoring of the remediation sites during a four-year field experiment showed that the grass cover is capable of sustainable functioning by neutralizing the acidity of peat soil, reducing the toxicity of soil solutions, and eliminating the imbalance of macronutrients. Serpentine minerals act as an alkaline barrier, reducing the intensity of migration of copper and nickel compounds.

A relevant and highly demanded modern medicine problem in many of its areas is the timely detection and recognition of pathogenic microorganisms and microbial communities in the patient’s tissues for the speedy prescription and correct use of medicines from mutually exclusive tactics. The transition to a new level in the speed of visualization of the samples’ contents taken and the accuracy of diagnostics is possible because of the use of lanthanide staining in combination with scanning electron microscopy to retrieve a series of high-resolution images with subsequent automatic labelling and classification of microbiological objects. This paper presents the results of using the YOLOv5 neural network model to detect 15 different most common opportunistic classes of bacteria in 380 images. As a result, a 71.5% average accuracy and 69.8% recall were achieved by using the YOLOv5 base model without freezing layers.

PURPOSE:This study provides a detailed analysis of the bioinorganic chemical composition of lens substance in patients with senile cataract using classical and spatial statistics methods. MATERIAL AND METHODS:The study included 30 isolated human lenses. The light scattering ability (LSA) of the lens substance was evaluated using an original method. Additionally, distribution of chemical elements in the lens substance was analyzed using a scanning electron microscope with energy dispersive spectrometer (SEM/EDS). Measurements by all methods were carried out in a single coordinate space, which made it possible to compare the spatial correlation of different parameters. RESULTS:Small-angle light scattering of the lens substance has been quantitatively characterized for the first time. In contrast to the conventional norm, in senile cataract the accumulation fields of the majority of ion-forming elements (including Na, P, K, Cl) are distributed along the lines repeating the geometry of the lens capsule. At the same time, the light scattering ability of certain areas of the lens is significantly correlated with changes in the concentrations of Na, P, K, Ca in these areas. In particular, one ion-forming element can be distinguished - Na: spatial change of its concentration in senile cataract is strongly associated with a local change in LSA of the lens with opacities clustering of any degree. Thus, a change in the nature of the Na accumulation in the lens volume can be considered the main marker of senile cataract formation. CONCLUSION:The distribution pattern of ion-forming elements indicates that the loss of barrier properties in the capsule plays a significant role in the development of senile cataract.

PURPOSE:The study attempted to experimentally substantiate the possibility of using the laser activation of scleral hydropermeability (LASH) technique in glaucoma treatment by morphological evaluation of treatment outcomes.MATERIAL AND METHODS:The pulsed-periodic radiation from an Er-glass fiber laser (λ=1.56 μm) was used. The model experiment consisted of evaluating ultrafiltration of fluid through the tissues of human sclera autopsy specimen according to the original technique using neodymium chloride-based labeling agent and scanning electron microscopy. The clinical part of the study consisted of optical coherence tomography (OCT) and laser confocal microscopy of the sclera and conjunctiva (CMSC) performed in vivo immediately after laser treatment in the laser application sites in 5 patients (5 eyes) aged 57 to 68 years with uncompensated advanced (IIIb-c) stage of glaucoma who had previously underwent LASH surgery.RESULTS:Results of morphological evaluation after LASH revealed structural changes indicating increased transscleral ultrafiltration: increased intrastromal hyporeflective areas in the sclera, thinning of collagen fibers, formation of porous structures. Using an original technique involving neodymium chloride-based labeling agent and scanning electron microscopy, we were able to prove the enhancement of transscleral ultrafiltration. The results of the experiment were confirmed by in vivo OCT images of the sclera and CMSC performed in 5 patients with advanced glaucoma after LASH surgery, in which tissue decompaction in the laser-exposed areas was clearly visualized.CONCLUSION:The revealed structural changes indicate the possibility of reducing intraocular pressure after LASH by the means of forming scleral porous structures and increasing transscleral ultrafiltration. Experimentally selected optimal mode of laser exposure (0.66 W with total exposure time of 6 seconds) during LASH helps avoid gross destructive changes in the eye tissues, making the proposed intervention a sparing approach to the treatment of glaucoma.