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1.
Opt Lett ; 49(13): 3664-3667, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38950235

RESUMEN

A bandgap in the continuum spectrum of photons in addition to its basic physical significance has strong potential for applications. Analogous to semiconductor crystals for electrons, periodic dielectric structures named photonic crystals were proposed to control photon flux propagation. In our search for low refractive index (RI) structures with a photonic bandgap, initial research efforts were focused on photonic crystal design, while aperiodic structures allow lower values of refractive index contrast to sustain a photonic bandgap. Here, we report on a two-dimensional quasicrystalline structure designed as a set of one-dimensional lattices merged into a single binary structure made of two materials with refractive index contrast 2|n1 - n2|/(n1 + n2) = 0.16 and even less in theory. We confirmed the theoretical prediction of bandgap exciting by measuring the radiation suppression of a dipole source placed in the center of the quasicrystalline structure. The full-wave numerical simulations and the experimental study appear to be in good agreement with the theoretical model.

2.
Pharmaceutics ; 15(3)2023 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-36986782

RESUMEN

In this study, a water-soluble form of haloperidol was obtained by coaggregation with calix[4]resorcinol bearing viologen groups on the upper rim and decyl chains on the lower rim to form vesicular nanoparticles. The formation of nanoparticles is achieved by the spontaneous loading of haloperidol into the hydrophobic domains of aggregates based on this macrocycle. The mucoadhesive and thermosensitive properties of calix[4]resorcinol-haloperidol nanoparticles were established by UV-, fluorescence and CD spectroscopy data. Pharmacological studies have revealed low in vivo toxicity of pure calix[4]resorcinol (LD50 is 540 ± 75 mg/kg for mice and 510 ± 63 mg/kg for rats) and the absence of its effect on the motor activity and psycho-emotional state of mice, which opens up a possibility for its use in the design of effective drug delivery systems. Haloperidol formulated with calix[4]resorcinol exhibits a cataleptogenic effect in rats both when administered intranasally and intraperitoneally. The effect of the intranasal administration of haloperidol with macrocycle in the first 120 min is comparable to the effect of commercial haloperidol, but the duration of catalepsy was shorter by 2.9 and 2.3 times (p < 0.05) at 180 and 240 min, respectively, than that of the control. There was a statistically significant reduction in the cataleptogenic activity at 10 and 30 min after the intraperitoneal injection of haloperidol with calix[4]resorcinol, then there was an increase in the activity by 1.8 times (p < 0.05) at 60 min, and after 120, 180 and 240 min the effect of this haloperidol formulation was at the level of the control sample.

3.
Artículo en Inglés | MEDLINE | ID: mdl-36786303

RESUMEN

Graphene-based materials are of interest in electrochemical biosensing due to their unique properties, such as high surface areas, unique electrochemical properties, and biocompatibility. However, the scalable production of graphene electrodes remains a challenge; it is typically slow, expensive, and inefficient. Herein, we reported a simple, fast, and maskless method for large-scale, low-cost reduced graphene oxide electrode fabrication; using direct writing (laser scribing and inkjet printing) coupled with a stamp-transferring method. In this process, graphene oxide is simultaneously reduced and patterned with a laser, before being press-stamped onto polyester sheets. The transferred electrodes were characterized by SEM, XPS, Raman, and electrochemical methods. The biosensing utility of the electrodes was demonstrated by developing an electrochemical test for Escherichia coli. These biosensors exhibited a wide dynamic range (917-2.1 × 107 CFU/mL) of low limits of detection (283 CFU/mL) using just 5 µL of sample. The test was also verified in spiked artificial urine, and the sensor was integrated into a portable wireless system driven and measured by a smartphone. This work demonstrates the potential to use these biosensors for real-world, point-of-care applications. Hypothetically, the devices are suitable for the detection of other pathogenic bacteria.

4.
J Mol Graph Model ; 118: 108338, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36201878

RESUMEN

We report a novel model of the selective binding mechanism of adenosine-specific DNA aptamer. Our theoretical investigations of AMP (Adenosine monophosphate) dissociation from aptamer-AMP complexes reveals new details of aptamer molecular specificity and stabilisation factors. Umbrella sampling MD calculations using parmbsc1 force field shows that the disordered structure of the internal loop of the unbound aptamer hairpin has a characteristic packing of guanines, which prevents barrier-free penetration of ligands into the site cavity. Also, this disordered structure of the unbound aptamer has a network of hydrogen bonds stabilising the cavity near the target guanines within the binding sites during the whole binding process. We suggested that the first AMP molecule binds to the disordered structure of the site closest to the aptamer hairpin stem and spends some free energy on ordering of the internal loop. Then the second AMP molecule binds to the ordered site closest to the aptamer hairpin loop with a lower energy gain. As a result, the induced-fit binding model is the most applicable for this aptamer and does not contradict the modern experimental NMR and calorimetry data.


Asunto(s)
Aptámeros de Nucleótidos , Aptámeros de Nucleótidos/química , Adenosina , Conformación de Ácido Nucleico , Muestreo , Adenosina Monofosfato/química , Sitios de Unión
5.
Langmuir ; 38(50): 15776-15781, 2022 12 20.
Artículo en Inglés | MEDLINE | ID: mdl-36473190

RESUMEN

The attachment of functional DNA to gold nanoparticles via polyadenine adsorption is a well-established technology. This approach was mainly viewed through the lens of changing the DNA charge in order to reduce the electrostatic barrier created by a similarly charged gold surface. However, altering the DNA charge results in the loss of its functionality. This work considers the adsorption process of polyadenines by force that artificially brings them closer to the surface. As a force source, we used the hybridization of a DNA strand carrying polyadenines with a complementary strand already attached to the surface. It was shown that the hybridization forces facilitated the adsorption of polyadenines. We believe that this approach is applicable in various areas where it is essential to preserve the functionality of DNA during conjugation with nanoparticles.


Asunto(s)
Nanopartículas del Metal , Nanopartículas , Oro , Adsorción , ADN , Propiedades de Superficie
6.
Phys Chem Chem Phys ; 24(41): 25307-25315, 2022 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-36226548

RESUMEN

The interaction between diphenylacetylene and dichlorophenylphosphine under various conditions is a simple method for the preparation of pentaphenylphosphole derivatives exhibiting fluorescence properties. Depending on the electronic state of the various centers of the phospholic structure, it was possible to obtain molecules with fluorescence, as in the blue area for 1,2,3,4,5-pentaphenyl-2,5-dihydro-phosphole-1-oxide (H2PPPO), in the yellow area for 1,2,3,4,5-pentaphenylphosphole-1-oxide (PPPO) and in the cyan area for 1,2,3,4,5-pentaphenylphosphole (PPP). The effect of the structure and π-conjugation on the optical properties of these compounds was studied using PPP derivatives as examples. Unusual changes in the optical properties of PPP derivatives in solution and in the crystalline state are explained. In the case of agglomeration of PPPO and PPP molecules, the effect of aggregation-induced emission (AIE) was observed to have weak fluorescence in solution and strong fluorescence in the aggregated state. However, for H2PPPO, the AIE effect remains mild. With the help of experimental studies, supported by theoretical calculations, the main mechanism of the optical properties of pentaphenylphosphole derivatives has been revealed. It was observed that the intramolecular motions of PPPO and PPP are more limited in the solid state than the motions of H2PPPO, which is associated with less conjugation of the phenyl rotors of H2PPPO. The analysis of the structure and distribution of electron density showed why hydrogenation of the phosphole ring leads to a sharp change in the optical properties of pentaphenylphosphole derivatives, while the oxidation of phosphorus does not lead to the disappearance of the AIE effect and to a lesser extent affects the change in the fluorescence wavelength. Thus, it was shown how the regulation of various structural features of the phospholic ring helps to control the optical properties of such compounds.

7.
Membranes (Basel) ; 12(9)2022 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-36135859

RESUMEN

The development of post-lithium current sources, such as sodium-ion batteries with improved energy characteristics and an increased level of safety, is one of the key issues of modern energy. It requires the search and study of materials (including electrolytes) for these devices. Polyelectrolytes with unipolar cationic conductivity based on Nafion® membranes are promising. In this work, the effect of swelling conditions of the Nafion® 115 membrane in Na+-form with mixtures of aprotic solvents such as ethylene carbonate and sulfolane on its physicochemical and electrotransport properties was studied. Nafion-Na+ membranes were swollen in a mixture of solvents at temperatures of 40, 60, and 80 °C. The results were obtained using methods of impedance spectroscopy, simultaneous thermal analysis, and IR spectroscopy. The best conductivity was observed for a membrane swelling at 80 °C in a mixture with a mass fraction of ethylene carbonate of 0.5, which reaches 10-4 S cm-1 at 30 °C and retains rather high values down to -60 °C (10-6 S cm-1). Thus, it is possible to expand the operating temperature range of a sodium battery by varying the composition of the polymer electrolyte and the conditions for its preparation.

8.
Inorg Chem ; 61(23): 8670-8684, 2022 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-35650511

RESUMEN

Imidoylamidinate-based heteroleptic bis(2-phenylbenzothiazole)iridium(III) and -rhodium(III) complexes [(bt)2M(N∩N)] (bt = 2-phenylbenzothiazole, N∩N = N'-(benzo[d]thiazol-2-yl)acetimidamidyl (Ir1 and Rh1), N'-(6-fluorobenzo[d]thiazol-2-yl)acetimidamidyl (Ir2), N'-(benzo[d]oxazol-2-yl)acetimidamidyl (Ir3), N'-(1-methyl-1H-benzo[d]imidazol-2-yl)acetimidamidyl (Ir4); yields 70-84%) were obtained by the reaction of the in situ-generated solvento-complex [(bt)2M(NCMe)2]NO3 and benzo[d]thia/oxa/N-methylimidozol-2-amines in the presence of NaOMe. Complexes Ir1-4 exhibited intense orange photoluminescence, reaching 37% at room temperature quantum yields, being immobilized in a poly(methyl methacrylate) matrix. A photophysical study of these species in a CH2Cl2 solution, neat powder, and frozen (77 K) MeOC2H4OH-EtOH glass matrix─along with density-functional theory (DFT), ab initio methods, and spin-orbit coupling time-dependent DFT calculations─verified the effects of substitution in the imidoylamidinate ligands on the excited-state properties. Electrochemical (cyclic voltammetry and differential pulse voltammetry) and theoretical DFT studies demonstrated noninnocent behavior of the imidoylamidinate ligands in Ir1-4 and Rh1 complexes due to the significant contribution coming from these ligands in the HOMO of the complexes. The iridium(III) species exhibit a ligand (L, 2-phenylbenzothiazole)-centered (3LC), metal-to-ligand (L', imidoylamidinate) charge-transfer (3ML'CT,3MLCT) character of their emission. The imidoylamidinate-based iridium(III) species were proved to be effective as the emissive dopant in an organic light-emitting diode device, fabricated in the framework of this study.

9.
Nanomaterials (Basel) ; 12(12)2022 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-35745324

RESUMEN

The combined method of treating malignant neoplasms using photodynamic therapy and chemotherapy is undoubtedly a promising and highly effective treatment method. The development and establishment of photodynamic cancer therapy is closely related to the creation of sensitizers based on porphyrins. The present study is devoted to the investigation of the spectroscopic, aggregation, and solubilization properties of the supramolecular system based on 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TSPP) and lanthanum-containing surfactant (LaSurf) in an aqueous medium. The latter is a complex of lanthanum nitrate and two cationic amphiphilic molecules of 4-aza-1-hexadecylazoniabicyclo[2.2.2]octane bromide. The mixed TSPP-LaSurf complexes can spontaneously assemble into various nanostructures capable of binding the anticancer drug cisplatin. Morphological behavior, stability, and ability to drug binding of nanostructures can be tailored by varying the molar ratio and the concentration of components. The guest binding is shown to be additional factor controlling structural rearrangements and properties of the supramolecular TSPP-LaSurf complexes.

10.
Vaccines (Basel) ; 10(6)2022 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-35746546

RESUMEN

Mass vaccination campaigns against COVID-19 affected more than 90% of the population in most developed countries. The new epidemiologic wave of COVID-19 has been ongoing since the end of 2021. It is caused by a virus variant B.1.1.529, also known as "Omicron" and its descendants. The effectiveness of major vaccines against Omicron is not known. The purpose of this study is to evaluate the efficacy of the Sputnik V vaccine. The main goal is to assess its protection against hospitalization in the period of Omicron dominance. We conducted our study based on a large clinical center in Moscow (Russia) where 1112 patients were included. We used the case-population method to perform the calculations. The data we obtained indicate that the Omicron variant causes at least 90% of infections in the studied cohort. The effectiveness of protection against hospitalization with COVID-19 in our study was 85.9% (95% CI 83.0-88.0%) for those who received more than one dose. It was 87.6% (95% CI 85.4-89.5%) and 97.0% (95% CI 95.9-97.8%) for those who received more than two or three doses. The effectiveness in cases of more severe forms was higher than for less severe ones. Thus, present study indicates the high protective efficacy of vaccination against hospitalization with COVID-19 in case of Omicron lineage.

11.
EClinicalMedicine ; 46: 101360, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35340627

RESUMEN

Background: HIV-infection is known to aggravate the course of many infectious diseases, including COVID-19. International guidance recommends vaccination of HIV+ individuals against SARS-CoV-2. There is a paucity of data on epidemiological efficacy assessment of COVID-19 vaccines among HIV+. This paper provides a preliminary assessment of Sputnik V vaccine effectiveness in HIV+ patients on antiretroviral therapy (ART). Methods: We performed a retrospective cohort study to assess the effectiveness of the standard Sputnik V vaccination regimen in 24,423 HIV+ Moscow residents during spring - summer 2021, that included dominance of delta variant, with estimation of hospitalization and severe illness rates in vaccinated and unvaccinated patients. Data were extracted from the Moscow anti-COVID-19 vaccination and COVID-19 incidence Registries. Findings: The data obtained indicate that Sputnik V epidemiological efficiency in the entire cohort of HIV+ on ART was 76·33%; in HIV+ with CD4+ ≥ 350 cells/µl, vaccine efficiency was 79·42%, avoiding hospitalization in 90·12% cases and protecting from the development of moderate or severe disease in 97·06%. For delta variant in this group the efficiency was 65·35%, avoiding the need for hospitalization in 75·77% cases and protecting from the development of moderate or severe disease in 93·05% of patients. There was a trend, although not statistically significant, of declining vaccine efficiency in immune-compromised individuals (CD4+ < 350 cells/µl). Interpretation: The study suggested epidemiological efficiency of immunization with Sputnik V in HIV+ ART-treated patients for the original and delta SARS-CoV-2 variants. Funding: Ministry of Health of Russia and Moscow Healthcare Department.

12.
ACS Appl Mater Interfaces ; 13(47): 56366-56374, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-34784712

RESUMEN

Ti2Nb2O9 with a tunnel-type structure is considered as a perspective negative electrode material for Li-ion batteries (LIBs) with theoretical capacity of 252 mAh g-1 corresponding to one-electron reduction/oxidation of Ti and Nb, but only ≈160 mAh g-1 has been observed practically. In this work, highly reversible capacity of 200 mAh g-1 with the average (de)lithiation potential of 1.5 V vs Li/Li+ is achieved for Ti2Nb2O9 with pseudo-2D layered morphology obtained via thermal decomposition of the NH4TiNbO5 intermediate prepared by K+→ H+→ NH4+ cation exchange from KTiNbO5. Using operando synchrotron powder X-ray diffraction (SXPD), single-phase (de)lithiation mechanism with 4.8% unit cell volume change is observed. Operando X-ray absorption near-edge structure (XANES) experiment revealed simultaneous Ti4+/Ti3+ and Nb5+/Nb4+ reduction/oxidation within the whole voltage range. Li+ migration barriers for Ti2Nb2O9 along [010] direction derived from density functional theory (DFT) calculations are within the 0.15-0.4 eV range depending on the Li content that is reflected in excellent C-rate capacity retention. Ti2Nb2O9 synthesized via the ion-exchange route appears as a strong contender to widely commercialized Ti-based negative electrode material Li4Ti5O12 in the next generation of high-performance LIBs.

13.
Materials (Basel) ; 14(20)2021 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-34683581

RESUMEN

The electrical conductivity of La0.5-xSr0.5FeO3-δ, investigated as a function of the nominal cation deficiency in the A-sublattice, x, varying from 0 to 0.02, has demonstrated a nonlinear dependence. An increase in the x value from 0 to 0.01 resulted in a considerable increase in electrical conductivity, which was shown to be attributed mainly to an increase in the mobility of the charge carriers. A combined analysis of the defect equilibrium and the charge transport in La0.5-xSr0.5FeO3-δ revealed the increase in the mobility of oxygen ions, electrons, and holes by factors of ~1.5, 1.3, and 1.7, respectively. The observed effect is assumed to be conditioned by a variation in the oxide structure under the action of the cationic vacancy formation. It was found that the cation deficiency limit in La0.5-xSr0.5FeO3-δ did not exceed 0.01. A small overstep of this limit was shown to result in the formation of (Sr,La)Fe12O19 impurity, which even in undetectable amounts reduced the conductivity of the material. The presence of (Sr,La)Fe12O19 impurity was revealed by X-ray diffraction on the ceramic surface after heat treatment at 1300 °C. It is most likely that the formation of traces of the liquid phase under these conditions is responsible for the impurity migration to the ceramic surface. The introduction of a cation deficiency of 0.01 into the A-sublattice of La0.5-xSr0.5FeO3-δ can be recommended as an effective means to enhance both the oxygen ion and the electron conductivity and improve ceramic sinterability.

14.
Colloids Surf B Biointerfaces ; 208: 112089, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34500201

RESUMEN

The mucus layer acts as a selective diffusion barrier that has an important effect on the efficiency of drug delivery systems in the human body. In this regard, currently the drug nanocarriers of various sizes and compositions are being widely developed to study their mucoadhesive properties i.e., the ability to interact with mucin. However, the effective interaction of drug composition with mucin does not guarantee the success due to the fact that there is a further barrier in the form of epithelial cells retained by calcium ions under the mucus layer. In this work, the interaction of mucin (porcine gastric mucin) with calixarenes is considered for the first time. The study of interaction between calixarenes, mucin and calcium ions by a complex of physicochemical methods showed that effective interaction with mucin requires cationic fragments, and binding with calcium is realized due to anionic fragments in the calixarene structure. Therefore, the combination of different chemical groups in the structure of drug nanocarrier plays an important role in successful mucosal drug delivery. Taking into account the wide possibilities of synthetic modification of the macrocyclic platform, calixarenes can find the application in the drug delivery across mucous barriers.


Asunto(s)
Mucinas , Resorcinoles , Acetatos , Animales , Sistemas de Liberación de Medicamentos , Humanos , Porcinos , Viológenos
15.
J Vis Exp ; (171)2021 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-34096916

RESUMEN

Mouse models have contributed significantly to understanding genetic and physiological factors involved in healthy cardiac function, how perturbations result in pathology, and how myocardial diseases may be treated. Cardiovascular magnetic resonance imaging (CMR) has become an indispensable tool for a comprehensive in vivo assessment of cardiac anatomy and function. This protocol shows detailed measurements of mouse heart left ventricular function, myocardial strain, and hemodynamic forces using 7-Tesla CMR. First, animal preparation and positioning in the scanner are demonstrated. Survey scans are performed for planning imaging slices in various short- and long-axis views. A series of prospective ECG-triggered short-axis (SA) movies (or CINE images) are acquired covering the heart from apex to base, capturing end-systolic and end-diastolic phases. Subsequently, single-slice, retrospectively gated CINE images are acquired in a midventricular SA view, and in 2-, 3-, and 4-chamber views, to be reconstructed into high-temporal resolution CINE images using custom-built and open-source software. CINE images are subsequently analyzed using dedicated CMR image analysis software. Delineating endomyocardial and epicardial borders in SA end-systolic and end-diastolic CINE images allows for the calculation of end-systolic and end-diastolic volumes, ejection fraction, and cardiac output. The midventricular SA CINE images are delineated for all cardiac time frames to extract a detailed volume-time curve. Its time derivative allows for the calculation of the diastolic function as the ratio of the early filling and atrial contraction waves. Finally, left ventricular endocardial walls in the 2-, 3-, and 4-chamber views are delineated using feature-tracking, from which longitudinal myocardial strain parameters and left ventricular hemodynamic forces are calculated. In conclusion, this protocol provides detailed in vivo quantification of the mouse cardiac parameters, which can be used to study temporal alterations in cardiac function in various mouse models of heart disease.


Asunto(s)
Ventrículos Cardíacos , Imagen por Resonancia Cinemagnética , Función Ventricular Izquierda , Animales , Ventrículos Cardíacos/diagnóstico por imagen , Hemodinámica , Imagen por Resonancia Magnética , Ratones , Contracción Miocárdica , Valor Predictivo de las Pruebas , Estudios Prospectivos , Reproducibilidad de los Resultados , Estudios Retrospectivos , Volumen Sistólico
16.
Polymers (Basel) ; 13(7)2021 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-33916722

RESUMEN

The use of dipolar aprotic solvents to swell lithiated Nafion ionomer membranes simultaneously serving as electrolyte and separator is of great interest for lithium battery applications. This work attempts to gain an insight into the physicochemical nature of a Li-Nafion ionomer material whose phase-separated nanostructure has been enhanced with a binary plasticiser comprising non-volatile high-boiling ethylene carbonate (EC) and sulfolane (SL). Gravimetric studies evaluating the influence both of mixing temperature (25 to 80 °C) and plasticiser composition (EC/SL ratio) on the solvent uptake of Li-Nafion revealed a hysteresis between heating and cooling modes. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) revealed that the saturation of a Nafion membrane with such a plasticiser led to a re-organisation of its amorphous structure, with crystalline regions remaining practically unchanged. Regardless of mixing temperature, the preservation of crystallites upon swelling is critical due to ionomer crosslinking provided by crystalline regions, which ensures membrane integrity even at very high solvent uptake (≈200% at a mixing temperature of 80 °C). The physicochemical properties of a swollen membrane have much in common with those of a chemically crosslinked polymer gel. The conductivity of ≈10-4 S cm-1 demonstrated by Li-Nafion membranes saturated with EC/SL at room temperature is promising for various practical applications.

17.
Nanotechnology ; 32(4): 045604, 2021 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-33045696

RESUMEN

Nanostructures synthesized using DNA-conjugated gold nanoparticles have a wide range of applications in the field of biosensorics. The stability of the DNA duplex plays a critical role as it determines the final geometry of these nanostructures. The main way to control DNA stability is to maintain a high ionic strength of the buffer solution; at the same time, high salt concentrations lead to an aggregation of nanoparticles. In this study, by means of the instrumentality of DNA-bridged seeds using tris(hydroxymethyl)aminomethane as a soft reducing agent the dumbbell-like gold nanoparticles up to 35 nm were synthesized with a high concentration of sodium ions of up to 100 mM and magnesium ions up to 1 mM. We also examined at the atomic level the details of the effect of the gold nanoparticle surface, as well as Na+ and Mg2+ ions, on the stability of nucleotide pairs located in close proximity to the grafting site.


Asunto(s)
ADN/química , Oro/química , Magnesio/química , Nanopartículas del Metal/química , Sodio/química , ADN/análisis , Concentración Osmolar
18.
Preprint en Inglés | medRxiv | ID: ppmedrxiv-20181396

RESUMEN

The use of computed tomography (CT) for the diagnostics of COVID-19 in the Russian Federation led to significant changes in the structure of X-ray diagnostics and levels of medical exposure of the patients. This study was aimed at the preliminary operative assessment of changes in the structure and collective dose from CT examinations in several representative hospitals, regions and on the level of the Russian Federation. The results of the study indicate that during the transformation of hospitals from general medical practice into dedicated COVID-19 facilities, the number of CT examinations increased up to 30%; the collective dose from CT exams increased up to a factor of 1.5. During a partial transformation of a medical facility into the hospital with separate COVID-19 departments, the increase in the number of CT examinations in the facility was more significant (up to a factor of 2 or more). These numbers correspond to 1.5 - 2.5 chest CT examinations (from 1 to 6) per patient admitted to hospital with COVID-19 diagnosis; and 1.2 chest CT examinations per patient in outpatient facilities, including a mandatory CT scan for the staging of COVID-19. The collective dose from CT examinations in the Russian Federation for March-June period of 2020 increased by the factor of 2 (from 16k man-Sv to 32k man-Sv); the collective dose of COVID-19 patients was about 12k man-Sv. For a more detailed and reliable assessment of the dynamics of changes in the structure of diagnostic radiology and levels of radiation exposure of patients in the Russian Federation, data collection in the regions of the Russian Federation and individual medical facilities will continue.

19.
Bioprocess Biosyst Eng ; 43(3): 549-567, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31786664

RESUMEN

The hollow fiber membrane bioreactor (HFMB) has been investigated for the cultivation of mammalian Chinese hamster ovary cell expansion. The experiments were carried out in Petri's dishes and in the hollow fiber membrane bioreactor having 20 fibers (S2025 from FiberCell Systems). The approach to HFMB modelling which combines the model of cell growth kinetics and hydrodynamics has been proposed. The hydrodynamic model is made using ANSYS Fluent software. The mathematical model of HFMB was developed, allowing the study of the hydrodynamics into the lumen and the extracapillary spaces, the filtration through the membrane fiber with the cell expansion on outer membrane surface. The direct nutrient medium flow variant into the extracapillary space was suggested. Based on the numerical simulations, the optimal parameters were selected for daily changes in the medium flow-rate into the lumen space. The HFMB scaling up was performed for the larger size HFMB (60 fibers).


Asunto(s)
Reactores Biológicos , Técnicas de Cultivo de Célula , Membranas Artificiales , Modelos Teóricos , Animales , Células CHO , Cricetinae , Cricetulus
20.
Mol Pharm ; 17(1): 40-49, 2020 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-31746611

RESUMEN

The addition of specific chemical groups in a macrocycle structure influences its functional properties and, consequently, can provide new possibilities, among which are aggregation properties, water solubility, biocompatibility, stimuli response, biological activity, etc. Herein, we report synthesis of new resorcin[4]arene with N-methyl-d-glucamine groups on the upper rim and n-decyl chains on the lower rim, an investigation of its self-assembly behavior in aqueous media, and its use as a building block for the formation of drug nanocontainer. N-methyl-d-glucamine fragments in the resorcin[4]arene structure promote higher stability in solutions, simplification of self-aggregation, and increased biological activity. Antimicrobial and hemolytic activity assessment revealed that this resorcin[4]arene obtained is nontoxic. The study of cell penetration was carried out with both free and encapsulated doxorubicin (DOX). Surprisingly, DOX-loaded macrocycle aggregates are more efficient in causing apoptosis in human cancer cell line. Conceivably, this knowledge will help in the rational design of DOX combination for novel drug-administration strategies in cancer treatment.


Asunto(s)
Apoptosis/efectos de los fármacos , Calixarenos/química , Portadores de Fármacos/química , Nanopartículas/química , Antibióticos Antineoplásicos/administración & dosificación , Calixarenos/síntesis química , Línea Celular Tumoral , Doxorrubicina/administración & dosificación , Hepatocitos/efectos de los fármacos , Humanos , Microscopía Electrónica de Transmisión , Nanopartículas/ultraestructura , Solubilidad
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