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1.
Microorganisms ; 12(2)2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38399672

RESUMO

Cytomegalovirus (CMV), in addition to other agents, is part of the TORCH complex (Toxoplasma gondii, Rubella virus, Cytomegalovirus, Herpes simplex viruses, and other agents). CMV infection is the most frequent cause of congenital malformations. This study aimed to establish the variation of prevalence of anti-CMV antibodies in pregnant women from the South-West region of Romania, according to demographic factors, such as age and area of residence, in two separate time periods (2013-2016 and 2019-2022). We collected from the hospital records the age, place of residence, and anti-CMV antibody test results using immune electrochemiluminescence and chemiluminescence. This study found that the seroprevalence of anti-CMV IgM antibodies increased slightly from 2013-2016 to 2019-2022, from 1.92% to 2.26%, and for IgG antibodies from 93.68% to 94.96%. In both groups was observed a descending trend of anti-CMV IgM seroprevalence with an increase in age, showing a decrease in seroprevalence from 3.57% to 1.09% in pregnant women from rural areas in the 31-35 years age group, while in urban areas, we observed a decrease in seroprevalence from 11.11% to 3.06% in the <20 years age group. The IgG seroprevalence showed an increase both in rural areas (from 93.97% to 95.52%) and urban areas (from 93.52% to 94.27%). In both groups, seroprevalence was higher in rural areas compared to urban regions. These results show a high rate of immunization against CMV in pregnant women in South-West Romania, which led to a low risk of acquiring the primary infection during pregnancy. However, the increase in the rate of primary CMV infections in pregnancy suggests the need for prioritizing screening programs and improving the existing protocols to enhance maternal and child healthcare.

2.
Microorganisms ; 11(8)2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37630617

RESUMO

Toxoplasmosis, caused by the obligate intracellular protozoan parasite Toxoplasma gondii (T. gondii), is a globally prevalent zoonotic disease with potentially severe implications for immunocompromised individuals, pregnant women, and their fetuses/children. This study examined the prevalence of anti-T. gondii IgM and IgG antibodies in two groups of childbearing age women, including 653 participants in Group 1 (2013-2016) and 3221 participants in Group 2 (2019-2022). Our results revealed a decrease in the overall positivity rate of anti-T. gondii IgM antibodies from 2.32% to 1.06%, suggesting improved public health interventions over time. However, there were variations among different age groups and between rural and urban environments, with a significant decrease in urban areas across all age groups from Group 1 to Group 2. Regarding anti-T. gondii IgG antibodies, we did not observe a significant change in the seropositivity rate between the two groups. In the rural population with an age group over 35 years, we observed the highest positivity rate in Group 2. This study provided information on the risk factors and burden of toxoplasmosis in women of childbearing age with data that can be valuable to public health policies and the planning of healthcare measures for effective toxoplasmosis management.

3.
Microorganisms ; 11(8)2023 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-37630680

RESUMO

Maternal-fetal infectious pathology-notably the TORCH panel (Toxoplasma gondii, rubella, Cytomegalovirus, and herpes simplex viruses)-critically impacts maternal and neonatal health. This review collates data on the seroprevalence of IgG and IgM antibodies against TORCH agents in Romanian women, aiming to discern regional and population differences and identify risk factors. Twenty studies were included in the review, revealing variable seroprevalence rates across the country. Regions such as Moldavia and Banat showed higher anti-T. gondii IgG seroprevalence rates than Bihor, with notable declines in Banat. Rural, older, and multiparous women showed elevated T. gondii IgG rates. Anti-rubella vaccine introduction significantly reduced the prevalence of anti-rubella IgG antibodies, but recent vaccination coverage decreases raise concerns. CMV and HSV seroprevalence varied geographically, with rural areas generally showing higher CMV rates and HSV influenced by factors like education level and number of sexual partners. Concurrent seroprevalence of multiple TORCH components in some cases underscores potential common risk factors. This study highlights the importance of continuous monitoring and preventive measures such as vaccinations and awareness campaigns to mitigate the health impact on the pregnant population.

4.
Int J Mol Sci ; 24(8)2023 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-37108531

RESUMO

The aim of this study was to prepare and characterize the glasses made of x(Fe2O3∙V2O5)∙(100 - x)[P2O5∙CaO] with x ranging of 0-50%. The contribution of Fe2O3 and V2O5 amount on the structure of P2O5·CaO matrix was investigated. The vitreous materials were characterized by XRD (X-ray diffraction analysis), EPR (Electron Paramagnetic Resonance) spectroscopy, and magnetic susceptibility measurements. A hyperfine structure typical for isolated V4+ ions was noticed to all spectra containing low amount of V2O5. The XRD spectra show the amorphous nature of samples, apart x = 50%. An overlap of the EPR spectrum of a broad line without the hyperfine structure characteristic of clustered ions was observed with increasing V2O5 content. The results of magnetic susceptibility measurements explain the antiferromagnetic or ferromagnetic interactions expressed between the iron and vanadium ions in the investigated glass.


Assuntos
Ferro , Vanádio , Vanádio/química , Cálcio/química , Fosfatos de Cálcio/química , Fenômenos Magnéticos , Vidro/química
5.
Clin Pract ; 14(1): 52-68, 2023 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-38248430

RESUMO

Surgical site infections persist as a substantial concern within the realm of hospital-acquired infections. This enduring issue is further compounded by the mounting challenge of antibiotic resistance, a surge in surgical interventions, and the presence of comorbidities among patients. Thus, a comprehensive exploration of all discernible risk factors, as well as proactive preventive and prophylactic strategies, becomes imperative. Moreover, the prevalence of multidrug-resistant microorganisms has reached alarming proportions. Consequently, there is an acute need to investigate and scrutinize all potential therapeutic interventions to counter this burgeoning threat. Consequently, the primary objective of this review is to meticulously assess the origins and risk elements intertwined with surgical site infections across a diverse spectrum of surgical procedures. As the medical landscape continues to evolve, this critical analysis seeks to provide a nuanced understanding of the multi-faceted factors contributing to surgical site infections, with the overarching aim of facilitating more effective management and mitigation strategies. By exploring these dimensions comprehensively, we endeavor to enhance patient safety and the quality of surgical care in this era of evolving healthcare challenges.

6.
Nanomaterials (Basel) ; 12(24)2022 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-36558348

RESUMO

The paper considers the new effects of the nanoscale state of matter, which open up prospects for the development of electronic devices using new physical principles. The contacts of chemically homogeneous nanoparticles of yttrium-stabilized zirconium oxide (ZrO2­x mol% Y2O3, x = 0, 3, 4, 8; YSZ) with different sizes of 7.5 nm and 9 nm; 7.5 nm and 11 nm; and 7.5 nm and 14 nm, respectively, was studied on direct current using nanostructured objects in the form of compacts obtained by high-hydrostatic pressure (HP-compacts of 300MPa). A unique size effect of the nonlinear (rectifying-type contact) dependence of the electrical properties (in the region U < 2.5 V, I ≤ 2.7 mA) of the contact of different-sized YSZ nanoparticles of the same chemical composition is revealed, which indicates the possibility of creating semiconductor structures of a new type (homogeneous electronics). The electronic structure of the near-surface regions of nanoparticles of studied oxide materials and the possibility of obtaining specifically rectifying properties of the contacts were studied theoretically. Models of surface states of the Tamm-type are constructed considering the Coulomb long-range action. The discovered energy variance and its dependence on the curvature of the surface of nanoparticles made it possible to study the conditions for the formation of a contact potential difference in cases of nanoparticles of the same radius (synergistic effect), different radii (doped and undoped variants), as well as to discover the possibility of describing a group of powder particles within the Anderson model. The determined effect makes it possible to solve the problem of diffusion instability of semiconductor heterojunctions and opens up prospects for creating electronic devices with a fundamentally new level of properties for use in various fields of the economy and breakthrough critical technologies.

7.
Antibiotics (Basel) ; 11(7)2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35884159

RESUMO

BACKGROUND: Rhizobium (Agrobacterium) species are plant aerobic bacteria, which in some cases can produce endophthalmitis in humans after corneal trauma. CASE PRESENTATION: A 42-year-old female patient presented in the Emergency Department of the Emergency County Hospital of Craiova, Romania, reporting pain, epiphora, and blurry vision in her right eye for about five days. This initial infectious keratitis episode was successfully resolved, but after 20 days she presented again after trauma with a leaf with corneal abscess. In the conjunctival secretion, R. radiobacter was identified. Despite antibiotherapy, the patient's state did not improve, and ultimately the eye was eviscerated. METHODS: A search was performed in the ProQuest, PubMed, and ScienceDirect databases for the terms Agrobacterium, Rhizobium, radiobacter, and eye. We eliminated non-human studies, editorials and commentaries, and non-relevant content, and excluded the duplicates. RESULTS: In total, 138 studies were initially obtained, and then we selected 26 studies for retrieval. After the selection process, we ended up including 17 studies in our analysis. Most studies reported R. radiobacter endophthalmitis after ocular surgical procedures or outdoor activities that involve exposure to soil. CONCLUSION: R. radiobacter is a rare cause of endophthalmitis after eye trauma that generally responds well to usual antibiotherapy, but occasionally can evolve to severe, leading to the loss of the eye.

8.
Nanomaterials (Basel) ; 12(11)2022 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-35683639

RESUMO

The dimensional effect of electric charge storage with a density of up to 270 µF/g by the hydrated ZrO2-nanoparticles system was determined. It was found that the place of localization of different charge carriers is the generalized heterophase boundary-nanoparticles surface. The supposed mechanism of the effect was investigated using the theory of dispersed systems, the band theory, and the theory of contact phenomena in semiconductors, which consists of the formation of localized electronic states in the nanoparticle material due to donor-acceptor interaction with the adsorption ionic atmosphere. The effect is relevant for modern nanoelectronics, microsystem technology, and printed electronics because it allows overcoming the basic physical restrictions on the size, temperature, and operation frequency of the device, caused by leakage currents.

9.
Life (Basel) ; 12(5)2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35629397

RESUMO

The crystallographic texture of the whole valves of bivalve mollusks from the family Unionidae Unio pictorum Linnaeus, 1758 and Anodonta cygnea Linnaeus, 1758 is studied using pole figures measured using neutron diffraction. The use of neutron diffraction, in contrast to X-rays, makes it possible to study the valves without destroying them. Thus, we can discuss the study of the global texture of the entire valve. It was revealed that the pole figures of aragonite in the valves repeat their shape. The pole density maxima for U. pictorum from the Danube Delta and the Gulf of Finland in the Baltic Sea, living at different salinities and temperatures, differs by 0.41 mrd. The maximum value of the crystallographic texture for A. cygnea from the Danube Delta was also measured (5.07 mrd). In terms of texture sharpness, it surpasses the shell of marine bivalve mollusks, which are partially or completely composed of aragonite. Although U. pictorum and Mya arenaria Linnaeus, 1758 have different microstructures, their pole figures are very similar in isolines pattern, but differ in pole density maxima. No relationship was found between the crystallographic texture and the microstructure in U. pictorum. In addition, we report good qualitative agreement between aragonite X-ray pole figures of Sinanodonta woodiana Lea, 1834 from the Czech river Luznice, and neutron pole figures of U. pictorum from the Danube Delta.

10.
Antibiotics (Basel) ; 11(4)2022 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-35453254

RESUMO

BACKGROUND: CTX-M betalactamases have shown a rapid spread in the recent years among Enterobacteriaceae and have become the most prevalent Extended Spectrum Beta-Lactamases (ESBLs) in many parts of the world. The introduction and dissemination of antibiotic-resistant genes limits options for treatment, increases mortality and morbidity in patients, and leads to longer hospitalization and expensive costs. We aimed to identify the beta-lactamases circulating encoded by the genes blaCTX-M-15, blaSHV-1 and blaTEM-1 in Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) strains. Furthermore, we established the associated resistance phenotypes among patients hospitalized in the Intensive Care Unit (ICU) from County Clinical Emergency Hospital of Craiova, Romania. METHODS: A total of 46 non-duplicated bacterial strains (14 strains of E. coli and 32 strains of K. pneumoniae), which were resistant to ceftazidime (CAZ) and cefotaxime (CTX) by Kirby-Bauer disk diffusion method, were identified using the automated VITEK2 system. Detection of ESBL-encoding genes and other resistance genes was carried out by PCR. RESULTS: E. coli strains were resistant to 3rd generation cephalosporins and moderately resistant to quinolones, whereas K. pneumoniae strains were resistant to penicillins, cephalosporins, and sulfamides, and moderately resistant to quinolones and carbapenems. Most E. coli strains harbored blaCTX-M-15 gene (13/14 strains), a single strain had the blaSHV-1 gene, but 11 strains harbored blaTEM-1 gene. The mcr-1 gene was not detected. We detected tet(A) gene in six strains and tet(B) in one strain. In K. pneumoniae strains we detected blaCTX-M-15 in 23 strains, blaSHV-1 in all strains and blaTEM-1 in 14 strains. The colistin resistance gene mcr-1 was not detected. The tetracycline gene tet(A) was detected in 11 strains, but the gene tet(B) was not detected in any strains. CONCLUSIONS: The development in antibiotic resistance highlights the importance of establishing policies to reduce antibiotic use and improving the national resistance surveillance system in order to create local antibiotic therapy guidelines.

11.
Rom J Morphol Embryol ; 63(4): 645-652, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36808200

RESUMO

Uveal malignant melanoma is a rare malignant tumor comprising less than 5% of melanoma cases. It is nevertheless the intraocular tumor with the highest incidence in adults, that arises from the melanocytes in the uveal tract. The authors present the case of a patient with locally advanced choroidal melanoma: from presentation to diagnosis, treatment, and prognosis. A 63-year-old female patient presented in the Ambulatory of the Emergency County Hospital, Craiova, Romania, on the February 1, 2021, accusing visual acuity drop and photophobia in her left eye for about three weeks. Pathology examination in Hematoxylin-Eosin (HE) staining reveals a dense cell proliferation, with small and medium spindle cells and pigment production. The following immunohistochemical markers were used in our study: human melanoma black 45 (HMB45), Ki67, cyclin D1, B-cell lymphoma 2 (Bcl2), S100, Wilms' tumor 1 (WT1), p16, and p53. Uveal melanoma is a malignant tumor that can arise in all the uveal components: iris, ciliary body, and choroid. Out of the three components, iris melanomas have the best prognosis, while ciliary body melanomas have the worst prognosis. It is mandatory for the patient to respect the follow-up schedule, as follow-ups can provide early diagnosis of eventual metastasis.


Assuntos
Neoplasias da Coroide , Melanoma , Neoplasias Uveais , Humanos , Adulto , Feminino , Pessoa de Meia-Idade , Neoplasias Uveais/química , Neoplasias Uveais/diagnóstico , Neoplasias Uveais/patologia , Neoplasias da Coroide/patologia , Melanoma/patologia , Olho/patologia
12.
Discoveries (Craiova) ; 9(3): e135, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34816003

RESUMO

Multiple sclerosis (MS) is a progressive and irreversible disease which affects the central nervous system (CNS) with still unknown etiology. Our study aimes to establish the homocysteine pattern that can predict the MS diseases progression and to identify a potential disease progression marker that can be easy to perform and non-invasive, in order to predict the diseases outcome. In order to achieve this goal, we included 10 adult RRMS subjects, 10 adult SPMS subjects and 10 age-matched healthy subjects. The homocysteine plasma level was measured using automated latex enhanced immunoassay and the cobalamin and folate measurements were performed using automated chemiluminescence immunoassay (CLIA). HCR was calculated by dividing the homocysteine plasma level by cobalamin plasma level. We found that the homocysteine level in plasma of both RRMS patients and SPMS group are significantly increased compared with the control group. There is a significantly higher concentration of homocysteine in SPMS group compared with the RRMS group. In addition, the HCR is significantly increased in SPMS compared with the RRMS group and is a very good index of disease severity.

13.
Nanomaterials (Basel) ; 11(10)2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34685114

RESUMO

Herein, we investigated the influence of two types of nanoparticle fillers, i.e., amorphous SiO2 and crystalline ZrO2, on the structural properties of their nanocomposites with high-density polyethylene (HDPE). The composite films were prepared by melt-blending with a filler content that varied from 1% to 20% v/v. The composites were characterized by small- and wide-angle x-ray scattering (SAXS and WAXS), small-angle neutron scattering (SANS), Raman spectroscopy, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). For both fillers, the nanoaggregates were evenly distributed in the polymer matrix and their initial state in the powders determined their surface roughness and fractal character. In the case of the nano-ZrO2 filler, the lamellar thickness and crystallinity degree remain unchanged over a broad range of filler concentrations. SANS and SEM investigation showed poor interfacial adhesion and the presence of voids in the interfacial region. Temperature-programmed SANS investigations showed that at elevated temperatures, these voids become filled due to the flipping motions of polymer chains. The effect was accompanied by a partial aggregation of the filler. For nano-SiO2 filler, the lamellar thickness and the degree of crystallinity increased with increasing the filler loading. SAXS measurements show that the ordering of the lamellae is disrupted even at a filler content of only a few percent. SEM images confirmed good interfacial adhesion and integrity of the SiO2/HDPE composite. This markedly different impact of both fillers on the composite structure is discussed in terms of nanoparticle surface properties and their affinity to the HDPE matrix.

14.
Int J Mol Sci ; 22(13)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34210014

RESUMO

Human serum transferrin (HST) is a glycoprotein involved in iron transport that may be a candidate for functionalized nanoparticles to bind and target cancer cells. In this study, the effects of the simple and doped with cobalt (Co) and copper (Cu) ferrihydrite nanoparticles (Fh-NPs, Cu-Fh-NPs, and Co-Fh-NPs) were studied by spectroscopic and molecular approaches. Fluorescence spectroscopy revealed a static quenching mechanism for all three types of Fh-NPs. All Fh-NPs interacted with HST with low affinity, and the binding was driven by hydrogen bonding and van der Waals forces for simple Fh-NPs and by hydrophobic interactions for Cu-Fh-NPs and Co-Fh-NPs binding, respectively. Of all samples, simple Fh-NPs bound the most to the HST binding site. Fluorescence resonance energy transfer (FRET) allowed the efficient determination of the energy transfer between HST and NPs and the distance at which the transfer takes place and confirmed the mechanism of quenching. The denaturation of the HST is an endothermic process, both in the case of apo HST and HST in the presence of the three types of Fh-NPs. Molecular docking studies revealed that Fh binds with a low affinity to HST (Ka = 9.17 × 103 M-1) in accord with the fluorescence results, where the interaction between simple Fh-NPs and HST was described by a binding constant of 9.54 × 103 M-1.


Assuntos
Cobalto/química , Compostos Férricos/síntese química , Transferrina/química , Transferrina/metabolismo , Cobre/química , Compostos Férricos/química , Transferência Ressonante de Energia de Fluorescência , Humanos , Ligação de Hidrogênio , Modelos Moleculares , Simulação de Acoplamento Molecular , Nanopartículas , Ligação Proteica , Conformação Proteica , Espectrometria de Fluorescência , Termodinâmica
15.
Rom J Morphol Embryol ; 62(2): 369-383, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35024725

RESUMO

Condyloma acuminatum (CA) is a pathology caused by the human papillomavirus (HPV). It is manifested by the appearance of warts in the vulvar, pubic, and anorectal regions, but can occur in other areas. It is a common disease that can be prevented by using measures such as condoms or vaccine. Topical, local, pharmacological, surgical, and excisional therapy options are available for this pathology. Macroscopically, it appears as a vegetative tumor, with a single implantation base that branches towards the periphery, with a cauliflower appearance. CA is defined microscopically by acanthosis, parakeratosis, papillomatosis and koilocytosis. Immunohistochemical studies can detect the presence of various HPV strains or viral antigens and can emphasize certain specific characteristics; e.g., in the case presented in this study, we observed that the tumor had a fulminant evolution due to a strong vascular base identified with anti-cluster of differentiation (CD) 34 antibody, by the existence of epithelial cells with a high degree of cell proliferation, as evidenced by the anti-Ki67 antibody, the inactivation of the tumor suppressor gene and the appearance of immunolabeling for the anti-p53 antibody, by the strong immunoreactivity for p63 which reveals the existence of cells with dysplastic and neoplastic transformation potential, but also by detecting the immunolabeling for p16INK4a that is associated with the existence of HPV. Also, the tumor was immunoreactive for cytokeratin (CK) AE1∕AE3, partially immunoreactive for CK5∕6 in the basal layer and negative for CK7, which demonstrates the squamous epithelial origin of the described tumor. Subepithelial cells of the inflammatory system have been identified, such as macrophages immunolabeled with anti-CD68 antibody, T-lymphocytes immunolabeled with anti-CD3 antibody and rare B-lymphocytes immunolabeled with anti-CD20 antibody, which demonstrates the strong cellular response to remove the virus from the structure. Surgical and excisional treatment was helpful for the patient, because she was able to resume normal sexual activity and defecation, and on the other hand, microscopic studies showed the potential for malignant transformation of CA.


Assuntos
Condiloma Acuminado , Inibidor p16 de Quinase Dependente de Ciclina , Feminino , Humanos , Imuno-Histoquímica , Papillomaviridae
16.
Rom J Morphol Embryol ; 62(2): 481-489, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35024736

RESUMO

The aim of the study was to observe, using scanning electron microscopy (SEM), the ratio of bacterial biofilm coverage of adenoidal tissue in children diagnosed with chronic rhinosinusitis (CR), compared to the ratio of adenoid bacterial biofilm coverage in children diagnosed with obstructive sleep apnea (OSA). We also performed histopathological and immunohistochemical tests to correlate the results with the images obtained from SEM. We estimated, using an image analysis program, the coverage ratio with bacterial biofilm on the surface of the lymphatic tissue. Adenoid vegetation extracted from children with CR had a higher percentage of bacterial biofilm coverage compared to the group diagnosed with OSA. In the nasopharynx of children with CR, the bacterial biofilm had a constant role of infection generator, and adenoidectomy was the only effective therapeutic procedure to relieve the symptoms. Allergy tests were performed in all children to establish a link between CR, OSA and allergic rhinitis.


Assuntos
Tonsila Faríngea , Sinusite , Apneia Obstrutiva do Sono , Adenoidectomia , Biofilmes , Criança , Humanos
17.
Saudi J Biol Sci ; 27(12): 3365-3375, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33304144

RESUMO

Colloidal suspensions of silver nanoparticles (AgNPs) with surface modified by capping with citrate ions were synthesized by chemical reduction method. Transmission and Scanning Electron Microscopy as well as darkfield Optical Microscopy provided information on the nanoparticle morphology, with fine symmetrical grains and log-normal fitted size distribution. Small Angle X-ray Scattering method allowed theoretical confirmation of colloidal silver nanoparticle fine granularity, based on measurements in the native fluid sample. UV-Vis spectrophotometry allowed studying the Localized Surface Plasmon Resonance band versus the stability of the citrate-AgNP sample after storage and after UV-C exposure. The colloidal AgNP impact on Phanerochaete chrysosporium environmental microorganisms was studied by specific biochemical investigations. Silver released from the colloidal suspension of AgNPs was supposed to induce changes in some antioxidant enzymes and in some enzymes of Krebs' cycle. Catalase activity was moderately changed (an increase with over 50%) as well as superoxide dismutase activity, while the diminution of the activities of four dehydrogenases synthesized in the fungus mycelium was emphasized also: a decrease with about 60% for malate dehydrogenase, with over 50% for isocitrate dehydrogenase and succinate dehydrogenase and with about 40% for alpha-ketoglutarate dehydrogenase. These findings suggested the nano-toxicological issues of citrate-AgNPs impact on the environmental beneficial microorganisms.

18.
Int J Biol Macromol ; 164: 3559-3567, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32890566

RESUMO

The binding between the enzyme lactate dehydrogenase (LDH) and ferrihydrite nanoparticles (Fh-NPs) was investigated by means of small-angle neutron scattering (SANS), Fourier-transform infrared (FTIR) spectroscopy, fluorescence and Förster resonance energy transfer (FRET) and molecular docking. Fh-NPs - LDH compounds of dimensions under 100 nm are formed. The conformational changes and the mechanism of interaction between LDH and Fh-NPs simple and doped with Cu and Co, and the effect of these NPs on the thermal denaturation of LDH were monitored. The quenching mechanism is static, the binding occurring with moderate affinity, being mainly driven by hydrogen bonding and van der Waals forces. FRET occurs at a minimal distance of 2.55 nm. Thermal denaturation of LDH in the presence of simple and doped Fh-NPs shows that the thermodynamic parameters of protein unfolding are significantly changed with temperature. The denaturation temperature of LDH shifts to higher values in the presence of all Fh-NPs, than in the case of simple LDH. The docking approach estimates the energy corresponding to the best fit of the ferrihydrite in the LDH binding site near Trp. These results have direct implications on the uses of the complex of LDH with Fh-NPs in various biochemical, biological, or clinical applications.


Assuntos
Compostos Férricos/química , L-Lactato Desidrogenase/química , Nanopartículas/química , Algoritmos , Fenômenos Químicos , Descoberta de Drogas , Modelos Teóricos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Estrutura Molecular , Ligação Proteica , Análise Espectral , Relação Estrutura-Atividade , Termodinâmica
19.
Materials (Basel) ; 13(2)2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31952236

RESUMO

Titanium-based composites-titanium and silver (TiAg) and titanium and carbon (TiC)-were synthesized by the Thermionic Vacuum Arc (TVA) method on substrates especially for gear wheels and camshaft coating as mechanical components of irrigation pumps. The films were characterized by surface morphology, microstructure, and roughness through X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Small-Angle Neutron Scattering (SANS). The silver (Ag) films crystallized into a cubic system with lattice a = 4.0833 Å at room temperature, indexed as cubic Ag group Fm3m. The crystallites were oriented in the [111] direction, and mean grain size was 111 = 265 Å. The TiC structure revealed a predominant cubic TiC phase, with a = 0.4098 as a lattice parameter determined by Cohen's method. Average roughness (Ra) was 8 nm for the as-grown 170 nm thick TiAg film, and 1.8 nm for the as-grown 120 nm thick TiC film. Characteristic SANS contribution was detected from the TiAg layer deposited on a substrate of high-quality stainless steel with 0.45% carbon (OLC45) in the range of 0.015 Å-1 ≤ Q ≤ 0.4 Å-1, revealing the presence of sharp surfaces and an averaged triaxial ellipsoidal core-shell object.

20.
Int J Mol Sci ; 21(24)2020 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-33419335

RESUMO

In the last few years, a great amount of attention has been given to nanoparticles research due to their physicochemical properties that allow their use in analytical instruments or in promising imaging applications on biological systems. The use of ferrihydrite nanoparticles (Fh-NPs) in practical applications implies a particular control of their magnetic properties, stability, biocompatibility, interaction with the surface of the target, and low toxicity. In this study, the formation and organization of human serum albumin (HSA) molecules around the simple Fh-NPs and Fh-NPs doped with Co and Cu were examined by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) in terms of morphology and particle size. The topology of all Fh-NPs shows an organized area of HSA around each type of Fh-NP. Molecular docking studies were used in order to determine the probable location of the ferrihydrite in the HSA structure. The thermal stability of these nanohybrids was further investigated by fluorimetry, using 214-Trp residue from HSA as a spectral sensor. The denaturation temperature (Tm) was determined, and stabilization of the HSA structure in the presence of Fh-NPs was discussed. This study could be a starting point for the development of different applications targeting the structure and stability of Fh-NPs complexes with proteins.


Assuntos
Compostos Férricos/química , Nanopartículas Metálicas/química , Albumina Sérica/química , Cobalto/química , Cobre/química , Humanos , Nanopartículas Metálicas/ultraestrutura , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Simulação de Acoplamento Molecular , Tamanho da Partícula , Albumina Sérica/ultraestrutura
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